[PATCH 1/8] kernel/exit.c: make sure current's nsproxy != NULL while checking caps

[PATCH 1/8] kernel/exit.c: make sure current's nsproxy != NULL while checking caps

[Lukasz Pawelczyk]

There is a rare case where current's nsproxy might be NULL but we are
required to check for credentials and capabilities. It sometimes happens
during an exit_group() syscall while destroying user's session (logging
out).

My understanding is that while we have to lock the task to get task's
nsproxy and check whether it's NULL, for the 'current' we don't have to
and it's expected not to be NULL. There is a code in the kernel
currently that does current->nsproxy->user_ns without any checks.
And include/linux/nsproxy.h confirms that:

2. when accessing (i.e. reading) current task's namespaces - no
   precautions should be taken - just dereference the pointers

There seem to be no crash currently because of this, but with accessing
nsproxy from LSM hooks there is. This is the backtrace:

0  smk_tskacc (task=0xffff88003b0b92e0, obj_known=0x2 <irq_stack_union+2>, mode=2, a=0xffff88003be53dd8) at security/smack/smack_access.c:261
1  0xffffffff8130e2aa in smk_curacc (obj_known=<optimized out>, mode=<optimized out>, a=<optimized out>) at security/smack/smack_access.c:318
2  0xffffffff8130a50d in smack_task_kill (p=0xffff88003b0b92e0, info=<optimized out>, sig=<optimized out>, secid=<optimized out>) at security/smack/smack_lsm.c:2071
3  0xffffffff812ea4f6 in security_task_kill (p=<optimized out>, info=<optimized out>, sig=<optimized out>, secid=<optimized out>) at security/security.c:952
4  0xffffffff8109ac80 in check_kill_permission (sig=15, info=0x0 <irq_stack_union>, t=0xffff88003b0b8000) at kernel/signal.c:796
5  0xffffffff8109d3ab in group_send_sig_info (sig=15, info=0x0 <irq_stack_union>, p=0xffff88003b0b8000) at kernel/signal.c:1296
6  0xffffffff8108e527 in forget_original_parent (father=<optimized out>) at kernel/exit.c:575
7  exit_notify (group_dead=<optimized out>, tsk=<optimized out>) at kernel/exit.c:606
8  do_exit (code=<optimized out>) at kernel/exit.c:775
9  0xffffffff8108ec0f in do_group_exit (exit_code=0) at kernel/exit.c:891
10 0xffffffff8108ec84 in SYSC_exit_group (error_code=<optimized out>) at kernel/exit.c:902
11 SyS_exit_group (error_code=<optimized out>) at kernel/exit.c:900

This backtrace clearly shows that there is an LSM hook task_kill() that
happens during an exit_group() syscall and that this happens after
exit_task_namespaces(). LSM hooks with namespaces might need nsproxy to
be able to check for capabilities. At this point this is impossible. The
current's nsproxy is already NULL/destroyed.

This is the case because exit_task_namespaces() is called before the
exit_notify() where all of the above happens. This patch changes their
order.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 kernel/exit.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 22fcc05..da1bb18 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -742,7 +742,6 @@ void do_exit(long code)
 	exit_fs(tsk);
 	if (group_dead)
 		disassociate_ctty(1);
-	exit_task_namespaces(tsk);
 	exit_task_work(tsk);
 	exit_thread();
 
@@ -763,6 +762,13 @@ void do_exit(long code)
 
 	TASKS_RCU(tasks_rcu_i = __srcu_read_lock(&tasks_rcu_exit_srcu));
 	exit_notify(tsk, group_dead);
+
+	/*
+	 * This should be after all things that potentially require
+	 * process's namespaces (e.g. capability checks).
+	 */
+	exit_task_namespaces(tsk);
+
 	proc_exit_connector(tsk);
 #ifdef CONFIG_NUMA
 	task_lock(tsk);
-- 
2.1.0

[PATCH 2/8] user_ns: 3 new hooks for LSM namespace operations

[Lukasz Pawelczyk]

This commit implements 3 new LSM hooks that provide the means for LSMs
to embed their own security context within user namespace, effectively
creating some sort of a user_ns related security namespace.

The first one to take advantage of this mechanism is Smack.

The hooks has been documented in the in the security.h below.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 include/linux/lsm_hooks.h      | 28 ++++++++++++++++++++++++++++
 include/linux/security.h       | 23 +++++++++++++++++++++++
 include/linux/user_namespace.h |  4 ++++
 kernel/user.c                  |  3 +++
 kernel/user_namespace.c        | 18 ++++++++++++++++++
 security/security.c            | 28 ++++++++++++++++++++++++++++
 6 files changed, 104 insertions(+)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index f014f25..b6e0c3d 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1260,6 +1260,23 @@
  *	audit_rule_init.
  *	@rule contains the allocated rule
  *
+ * @userns_create:
+ *	Allocates and fills the security part of a new user namespace.
+ *	@ns points to a newly created user namespace.
+ *	Returns 0 or an error code.
+ *
+ * @userns_free:
+ *	Deallocates the security part of a user namespace.
+ *	@ns points to a user namespace about to be destroyed.
+ *
+ * @userns_setns:
+ *	Run during a setns syscall to add a process to an already existing
+ *	user namespace. Returning failure here will block the operation
+ *	requested from userspace (setns() with CLONE_NEWUSER).
+ *	@nsproxy contains a nsproxy to which the user namespace will be assigned.
+ *	@ns contains user namespace that is to be incorporated to the nsproxy.
+ *	Returns 0 or an error code.
+ *
  * @inode_notifysecctx:
  *	Notify the security module of what the security context of an inode
  *	should be.  Initializes the incore security context managed by the
@@ -1611,6 +1628,12 @@ union security_list_options {
 				struct audit_context *actx);
 	void (*audit_rule_free)(void *lsmrule);
 #endif /* CONFIG_AUDIT */
+
+#ifdef CONFIG_SECURITY
+	int (*userns_create)(struct user_namespace *ns);
+	void (*userns_free)(struct user_namespace *ns);
+	int (*userns_setns)(struct nsproxy *nsproxy, struct user_namespace *ns);
+#endif /* CONFIG_SECURITY */
 };
 
 struct security_hook_heads {
@@ -1822,6 +1845,11 @@ struct security_hook_heads {
 	struct list_head audit_rule_match;
 	struct list_head audit_rule_free;
 #endif /* CONFIG_AUDIT */
+#ifdef CONFIG_SECURITY
+	struct list_head userns_create;
+	struct list_head userns_free;
+	struct list_head userns_setns;
+#endif /* CONFIG_SECURITY */
 };
 
 /*
diff --git a/include/linux/security.h b/include/linux/security.h
index 8c8175d..ec17ae1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1583,6 +1583,29 @@ static inline void security_audit_rule_free(void *lsmrule)
 #endif /* CONFIG_SECURITY */
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_SECURITY
+int security_userns_create(struct user_namespace *ns);
+void security_userns_free(struct user_namespace *ns);
+int security_userns_setns(struct nsproxy *nsproxy, struct user_namespace *ns);
+
+#else
+
+static inline int security_userns_create(struct user_namespace *ns)
+{
+	return 0;
+}
+
+static inline void security_userns_free(struct user_namespace *ns)
+{ }
+
+static inline int security_userns_setns(struct nsproxy *nsproxy,
+					struct user_namespace *ns)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SECURITY */
+
 #ifdef CONFIG_SECURITYFS
 
 extern struct dentry *securityfs_create_file(const char *name, umode_t mode,
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 8297e5b..a9400cc 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -39,6 +39,10 @@ struct user_namespace {
 	struct key		*persistent_keyring_register;
 	struct rw_semaphore	persistent_keyring_register_sem;
 #endif
+
+#ifdef CONFIG_SECURITY
+	void *security;
+#endif
 };
 
 extern struct user_namespace init_user_ns;
diff --git a/kernel/user.c b/kernel/user.c
index b069ccb..ce5419e 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -59,6 +59,9 @@ struct user_namespace init_user_ns = {
 	.persistent_keyring_register_sem =
 	__RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem),
 #endif
+#ifdef CONFIG_SECURITY
+	.security = NULL,
+#endif
 };
 EXPORT_SYMBOL_GPL(init_user_ns);
 
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 4109f83..cadffb6 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -22,6 +22,7 @@
 #include <linux/ctype.h>
 #include <linux/projid.h>
 #include <linux/fs_struct.h>
+#include <linux/security.h>
 
 static struct kmem_cache *user_ns_cachep __read_mostly;
 static DEFINE_MUTEX(userns_state_mutex);
@@ -108,6 +109,15 @@ int create_user_ns(struct cred *new)
 
 	set_cred_user_ns(new, ns);
 
+#ifdef CONFIG_SECURITY
+	ret = security_userns_create(ns);
+	if (ret) {
+		ns_free_inum(&ns->ns);
+		kmem_cache_free(user_ns_cachep, ns);
+		return ret;
+	}
+#endif
+
 #ifdef CONFIG_PERSISTENT_KEYRINGS
 	init_rwsem(&ns->persistent_keyring_register_sem);
 #endif
@@ -143,6 +153,9 @@ void free_user_ns(struct user_namespace *ns)
 #ifdef CONFIG_PERSISTENT_KEYRINGS
 		key_put(ns->persistent_keyring_register);
 #endif
+#ifdef CONFIG_SECURITY
+		security_userns_free(ns);
+#endif
 		ns_free_inum(&ns->ns);
 		kmem_cache_free(user_ns_cachep, ns);
 		ns = parent;
@@ -969,6 +982,7 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
 {
 	struct user_namespace *user_ns = to_user_ns(ns);
 	struct cred *cred;
+	int err;
 
 	/* Don't allow gaining capabilities by reentering
 	 * the same user namespace.
@@ -986,6 +1000,10 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
 	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
 		return -EPERM;
 
+	err = security_userns_setns(nsproxy, user_ns);
+	if (err)
+		return err;
+
 	cred = prepare_creds();
 	if (!cred)
 		return -ENOMEM;
diff --git a/security/security.c b/security/security.c
index bd4c5f6..e902f3b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -25,6 +25,7 @@
 #include <linux/mount.h>
 #include <linux/personality.h>
 #include <linux/backing-dev.h>
+#include <linux/user_namespace.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -1541,6 +1542,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
 }
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_SECURITY
+
+int security_userns_create(struct user_namespace *ns)
+{
+	return call_int_hook(userns_create, 0, ns);
+}
+
+void security_userns_free(struct user_namespace *ns)
+{
+	call_void_hook(userns_free, ns);
+}
+
+int security_userns_setns(struct nsproxy *nsproxy, struct user_namespace *ns)
+{
+	return call_int_hook(userns_setns, 0, nsproxy, ns);
+}
+
+#endif /* CONFIG_SECURITY */
+
 struct security_hook_heads security_hook_heads = {
 	.binder_set_context_mgr =
 		LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr),
@@ -1885,4 +1905,12 @@ struct security_hook_heads security_hook_heads = {
 	.audit_rule_free =
 		LIST_HEAD_INIT(security_hook_heads.audit_rule_free),
 #endif /* CONFIG_AUDIT */
+#ifdef CONFIG_SECURITY
+	.userns_create =
+		LIST_HEAD_INIT(security_hook_heads.userns_create),
+	.userns_free =
+		LIST_HEAD_INIT(security_hook_heads.userns_free),
+	.userns_setns =
+		LIST_HEAD_INIT(security_hook_heads.userns_setns),
+#endif /* CONFIG_SECURITY */
 };
-- 
2.1.0

[PATCH 3/8] smack: extend capability functions and fix 2 checks

[Lukasz Pawelczyk]

This patch extends smack capability functions to a full list to those
equivalent in the kernel

has_ns_capability -> smack_has_ns_privilege
has_capability    -> smack_has_privilege
ns_capable        -> smack_ns_privileged
capable           -> smack_privileged

It also puts the smack related part to a common function:
smack_capability_allowed()

Those functions will be needed for capability checks in the upcoming
Smack namespace patches.

Additionally there were 2 smack capability checks that used generic
capability functions instead of specific Smack ones effectively ignoring
the onlycap rule. This has been fixed now with the introduction of those
new functions.

This has implications on the Smack namespace as well as the additional
Smack checks in smack_capability_allowed() will be extended beyond the
onlycap rule. Not using Smack specific checks in those 2 places could
mean breaking the Smack label namespace separation.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h     | 63 +++++++++++++++++++++++++++++++++++++++++++---
 security/smack/smack_lsm.c |  4 +--
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index b8c1a86..fa8fa87 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -332,21 +332,76 @@ static inline struct smack_known *smk_of_current(void)
 }
 
 /*
+ * Internal smack capability check complimentary to the
+ * set of kernel capable() and has_capability() functions
+ *
+ * For a capability in smack related checks to be effective it needs to:
+ * - have empty onlycap or the current label be the same as onlycap
+ * - be in the initial user ns
+ */
+static inline int smack_capability_allowed(struct smack_known *skp,
+					   struct user_namespace *user_ns)
+{
+	if (user_ns != &init_user_ns)
+		return 0;
+
+	if (smack_onlycap != NULL && smack_onlycap != skp)
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Is the task privileged in a namespace and allowed to be privileged
+ * by additional smack rules.
+ */
+static inline int smack_has_ns_privilege(struct task_struct *task,
+					 struct user_namespace *user_ns,
+					 int cap)
+{
+	struct smack_known *skp = smk_of_task_struct(task);
+
+	if (!has_ns_capability(task, user_ns, cap))
+		return 0;
+	if (smack_capability_allowed(skp, user_ns))
+		return 1;
+	return 0;
+}
+
+/*
  * Is the task privileged and allowed to be privileged
- * by the onlycap rule.
+ * by additional smack rules.
  */
-static inline int smack_privileged(int cap)
+static inline int smack_has_privilege(struct task_struct *task, int cap)
+{
+	return smack_has_ns_privilege(task, &init_user_ns, cap);
+}
+
+/*
+ * Is the current task privileged in a namespace and allowed to be privileged
+ * by additional smack rules.
+ */
+static inline int smack_ns_privileged(struct user_namespace *user_ns, int cap)
 {
 	struct smack_known *skp = smk_of_current();
 
-	if (!capable(cap))
+	if (!ns_capable(user_ns, cap))
 		return 0;
-	if (smack_onlycap == NULL || smack_onlycap == skp)
+	if (smack_capability_allowed(skp, user_ns))
 		return 1;
 	return 0;
 }
 
 /*
+ * Is the current task privileged and allowed to be privileged
+ * by additional smack rules.
+ */
+static inline int smack_privileged(int cap)
+{
+	return smack_ns_privileged(&init_user_ns, cap);
+}
+
+/*
  * logging functions
  */
 #define SMACK_AUDIT_DENIED 0x1
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a143328..ee7bb63 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -403,7 +403,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
 			rc = -EACCES;
-		else if (capable(CAP_SYS_PTRACE))
+		else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
 			rc = 0;
 		else
 			rc = -EACCES;
@@ -1646,7 +1646,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 	skp = file->f_security;
 	rc = smk_access(skp, tkp, MAY_WRITE, NULL);
 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc);
-	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
+	if (rc != 0 && smack_has_privilege(tsk, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
-- 
2.1.0

[PATCH 4/8] smack: abstraction layer for 2 common Smack operations

[Lukasz Pawelczyk]

This patch adds two new functions that provide an abstraction layer for
two common internal Smack operations:

smk_find_label_name() - returns a label name (char*) from a struct
                        smack_known pointer
smk_get_label()       - either finds or imports a label from a raw label
                        name (char*) and returns struct smack_known point

This patch also simplifies some pieces of code due to addition of those
2 functions (e.g. smack_inode_post_setxattr, smk_fill_rule,
smk_write_revoke_subj).

It is meant as a preparation for namespaces patches. Those 2 functions
will serve as entry points for namespace operations.

This patch should not change the Smack behaviour in any way.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h        |   2 +
 security/smack/smack_access.c |  40 ++++++++++++
 security/smack/smack_lsm.c    |  76 ++++++++++++-----------
 security/smack/smackfs.c      | 137 ++++++++++++++++++++++--------------------
 4 files changed, 155 insertions(+), 100 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index fa8fa87..fa32495 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -249,6 +249,8 @@ int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 struct smack_known *smk_import_entry(const char *, int);
 void smk_insert_entry(struct smack_known *skp);
 struct smack_known *smk_find_entry(const char *);
+char *smk_find_label_name(struct smack_known *skp);
+struct smack_known *smk_get_label(const char *string, int len, bool import);
 
 /*
  * Shared data.
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 408e20b..3bf4cad 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -617,3 +617,43 @@ struct smack_known *smack_from_secid(const u32 secid)
 	rcu_read_unlock();
 	return &smack_known_invalid;
 }
+
+/**
+ * smk_find_label_name - A helper to get a string value of a label
+ * @skp: a label we want a string value from
+ *
+ * Returns a pointer to a label name or NULL if label name not found.
+ */
+char *smk_find_label_name(struct smack_known *skp)
+{
+	return skp->smk_known;
+}
+
+/**
+ * smk_get_label - A helper to get the smack_known value from a string using
+ *                 either import or find functions if it already exists
+ * @string: a name of a label we look for or want to import
+ * @len: the string size, or zero if it is NULL terminated
+ * @import: whether we should import the label if not found
+ *
+ * Returns a smack_known label that is either imported or found.
+ * NULL if label not found (only when import == false).
+ * Error code otherwise.
+ */
+struct smack_known *smk_get_label(const char *string, int len, bool import)
+{
+	struct smack_known *skp;
+	char *cp;
+
+	if (import) {
+		skp = smk_import_entry(string, len);
+	} else {
+		cp = smk_parse_smack(string, len);
+		if (IS_ERR(cp))
+			return ERR_CAST(cp);
+
+		skp = smk_find_entry(cp);
+	}
+
+	return skp;
+}
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index ee7bb63..4a197b6 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -608,7 +608,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
 			op += strlen(SMK_FSHAT);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_hat = skp;
@@ -616,7 +616,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
 			op += strlen(SMK_FSFLOOR);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_floor = skp;
@@ -625,7 +625,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		} else if (strncmp(op, SMK_FSDEFAULT,
 				   strlen(SMK_FSDEFAULT)) == 0) {
 			op += strlen(SMK_FSDEFAULT);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_default = skp;
@@ -633,7 +633,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
 			op += strlen(SMK_FSROOT);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -641,7 +641,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
 			op += strlen(SMK_FSTRANS);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -1125,7 +1125,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 		rc = -EPERM;
 
 	if (rc == 0 && check_import) {
-		skp = size ? smk_import_entry(value, size) : NULL;
+		skp = size ? smk_get_label(value, size, true) : NULL;
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else if (skp == NULL || (check_star &&
@@ -1159,6 +1159,7 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 				      const void *value, size_t size, int flags)
 {
 	struct smack_known *skp;
+	struct smack_known **skpp = NULL;
 	struct inode_smack *isp = d_backing_inode(dentry)->i_security;
 
 	if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
@@ -1166,27 +1167,21 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 		return;
 	}
 
-	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
-		skp = smk_import_entry(value, size);
-		if (!IS_ERR(skp))
-			isp->smk_inode = skp;
-		else
-			isp->smk_inode = &smack_known_invalid;
-	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
-		skp = smk_import_entry(value, size);
-		if (!IS_ERR(skp))
-			isp->smk_task = skp;
-		else
-			isp->smk_task = &smack_known_invalid;
-	} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
-		skp = smk_import_entry(value, size);
+	if (strcmp(name, XATTR_NAME_SMACK) == 0)
+		skpp = &isp->smk_inode;
+	else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0)
+		skpp = &isp->smk_task;
+	else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
+		skpp = &isp->smk_mmap;
+
+	if (skpp) {
+		skp = smk_get_label(value, size, true);
+
 		if (!IS_ERR(skp))
-			isp->smk_mmap = skp;
+			*skpp = skp;
 		else
-			isp->smk_mmap = &smack_known_invalid;
+			*skpp = &smack_known_invalid;
 	}
-
-	return;
 }
 
 /**
@@ -1280,15 +1275,17 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	struct socket *sock;
 	struct super_block *sbp;
 	struct inode *ip = (struct inode *)inode;
-	struct smack_known *isp;
-	int ilen;
+	struct smack_known *isp = NULL;
 	int rc = 0;
 
-	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
+	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0)
 		isp = smk_of_inode(inode);
-		ilen = strlen(isp->smk_known);
-		*buffer = isp->smk_known;
-		return ilen;
+
+	if (isp) {
+		*buffer = smk_find_label_name(isp);
+		if (*buffer == NULL)
+			*buffer = smack_known_huh.smk_known;
+		return strlen(*buffer);
 	}
 
 	/*
@@ -1311,10 +1308,11 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	else
 		return -EOPNOTSUPP;
 
-	ilen = strlen(isp->smk_known);
 	if (rc == 0) {
-		*buffer = isp->smk_known;
-		rc = ilen;
+		*buffer = smk_find_label_name(isp);
+		if (*buffer == NULL)
+			*buffer = smack_known_huh.smk_known;
+		rc = strlen(*buffer);
 	}
 
 	return rc;
@@ -3270,7 +3268,10 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	cp = kstrdup(skp->smk_known, GFP_KERNEL);
+	cp = smk_find_label_name(skp);
+	if (cp == NULL)
+		cp = smack_known_huh.smk_known;
+	cp = kstrdup(cp, GFP_KERNEL);
 	if (cp == NULL)
 		return -ENOMEM;
 
@@ -3314,7 +3315,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	skp = smk_import_entry(value, size);
+	skp = smk_get_label(value, size, true);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
 
@@ -4042,7 +4043,10 @@ static int smack_key_getsecurity(struct key *key, char **_buffer)
 		return 0;
 	}
 
-	copy = kstrdup(skp->smk_known, GFP_KERNEL);
+	copy = smk_find_label_name(skp);
+	if (copy == NULL)
+		copy = smack_known_huh.smk_known;
+	copy = kstrdup(copy, GFP_KERNEL);
 	if (copy == NULL)
 		return -ENOMEM;
 	length = strlen(copy) + 1;
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 3e42426..5ec1e8e 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -345,36 +345,17 @@ static int smk_fill_rule(const char *subject, const char *object,
 				struct smack_parsed_rule *rule, int import,
 				int len)
 {
-	const char *cp;
-	struct smack_known *skp;
-
-	if (import) {
-		rule->smk_subject = smk_import_entry(subject, len);
-		if (IS_ERR(rule->smk_subject))
-			return PTR_ERR(rule->smk_subject);
-
-		rule->smk_object = smk_import_entry(object, len);
-		if (IS_ERR(rule->smk_object))
-			return PTR_ERR(rule->smk_object);
-	} else {
-		cp = smk_parse_smack(subject, len);
-		if (IS_ERR(cp))
-			return PTR_ERR(cp);
-		skp = smk_find_entry(cp);
-		kfree(cp);
-		if (skp == NULL)
-			return -ENOENT;
-		rule->smk_subject = skp;
-
-		cp = smk_parse_smack(object, len);
-		if (IS_ERR(cp))
-			return PTR_ERR(cp);
-		skp = smk_find_entry(cp);
-		kfree(cp);
-		if (skp == NULL)
-			return -ENOENT;
-		rule->smk_object = skp;
-	}
+	rule->smk_subject = smk_get_label(subject, len, import);
+	if (IS_ERR(rule->smk_subject))
+		return PTR_ERR(rule->smk_subject);
+	if (rule->smk_subject == NULL)
+		return -ENOENT;
+
+	rule->smk_object = smk_get_label(object, len, import);
+	if (IS_ERR(rule->smk_object))
+		return PTR_ERR(rule->smk_object);
+	if (rule->smk_object == NULL)
+		return -ENOENT;
 
 	rule->smk_access1 = smk_perm_from_str(access1);
 	if (access2)
@@ -605,6 +586,9 @@ static void smk_seq_stop(struct seq_file *s, void *v)
 
 static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 {
+	char *sbj;
+	char *obj;
+
 	/*
 	 * Don't show any rules with label names too long for
 	 * interface file (/smack/load or /smack/load2)
@@ -618,9 +602,13 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	if (srp->smk_access == 0)
 		return;
 
-	seq_printf(s, "%s %s",
-		   srp->smk_subject->smk_known,
-		   srp->smk_object->smk_known);
+	sbj = smk_find_label_name(srp->smk_subject);
+	obj = smk_find_label_name(srp->smk_object);
+
+	if (sbj == NULL || obj == NULL)
+		return;
+
+	seq_printf(s, "%s %s", sbj, obj);
 
 	seq_putc(s, ' ');
 
@@ -811,6 +799,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
 	char sep = '/';
+	char *cp;
 	int i;
 
 	/*
@@ -824,7 +813,11 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	if (strlen(skp->smk_known) >= SMK_LABELLEN)
 		return 0;
 
-	seq_printf(s, "%s %3d", skp->smk_known, skp->smk_netlabel.attr.mls.lvl);
+	cp = smk_find_label_name(skp);
+	if (cp == NULL)
+		return 0;
+
+	seq_printf(s, "%s %3d", cp, skp->smk_netlabel.attr.mls.lvl);
 
 	for (i = netlbl_catmap_walk(cmp, 0); i >= 0;
 	     i = netlbl_catmap_walk(cmp, i + 1)) {
@@ -913,7 +906,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 	 */
 	mutex_lock(&smack_cipso_lock);
 
-	skp = smk_import_entry(rule, 0);
+	skp = smk_get_label(rule, 0, true);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -1002,9 +995,14 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
 	char sep = '/';
+	char *cp;
 	int i;
 
-	seq_printf(s, "%s %3d", skp->smk_known, skp->smk_netlabel.attr.mls.lvl);
+	cp = smk_find_label_name(skp);
+	if (cp == NULL)
+		return 0;
+
+	seq_printf(s, "%s %3d", cp, skp->smk_netlabel.attr.mls.lvl);
 
 	for (i = netlbl_catmap_walk(cmp, 0); i >= 0;
 	     i = netlbl_catmap_walk(cmp, i + 1)) {
@@ -1087,11 +1085,15 @@ static int netlbladdr_seq_show(struct seq_file *s, void *v)
 	unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
 	int maskn;
 	u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
+	char *label = smk_find_label_name(skp->smk_label);
+
+	if (label == NULL)
+		return 0;
 
 	for (maskn = 0; temp_mask; temp_mask <<= 1, maskn++);
 
 	seq_printf(s, "%u.%u.%u.%u/%d %s\n",
-		hp[0], hp[1], hp[2], hp[3], maskn, skp->smk_label->smk_known);
+		hp[0], hp[1], hp[2], hp[3], maskn, label);
 
 	return 0;
 }
@@ -1237,7 +1239,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	 * If smack begins with '-', it is an option, don't import it
 	 */
 	if (smack[0] != '-') {
-		skp = smk_import_entry(smack, 0);
+		skp = smk_get_label(smack, 0, true);
 		if (IS_ERR(skp)) {
 			rc = PTR_ERR(skp);
 			goto free_out;
@@ -1566,6 +1568,7 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
 	ssize_t rc;
+	char *cp;
 	int asize;
 
 	if (*ppos != 0)
@@ -1576,12 +1579,14 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 	 */
 	mutex_lock(&smack_ambient_lock);
 
-	asize = strlen(smack_net_ambient->smk_known) + 1;
+	cp = smk_find_label_name(smack_net_ambient);
+	if (cp == NULL)
+		cp = smack_known_huh.smk_known;
+
+	asize = strlen(cp) + 1;
 
 	if (cn >= asize)
-		rc = simple_read_from_buffer(buf, cn, ppos,
-					     smack_net_ambient->smk_known,
-					     asize);
+		rc = simple_read_from_buffer(buf, cn, ppos, cp, asize);
 	else
 		rc = -EINVAL;
 
@@ -1619,7 +1624,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 		goto out;
 	}
 
-	skp = smk_import_entry(data, count);
+	skp = smk_get_label(data, count, true);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -1663,8 +1668,11 @@ static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
 	if (*ppos != 0)
 		return 0;
 
-	if (smack_onlycap != NULL)
-		smack = smack_onlycap->smk_known;
+	if (smack_onlycap != NULL) {
+		smack = smk_find_label_name(smack_onlycap);
+		if (smack == NULL)
+			smack = smack_known_huh.smk_known;
+	}
 
 	asize = strlen(smack) + 1;
 
@@ -1719,7 +1727,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_import_entry(data, count);
+	skp = smk_get_label(data, count, true);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -1760,8 +1768,11 @@ static ssize_t smk_read_unconfined(struct file *filp, char __user *buf,
 	if (*ppos != 0)
 		return 0;
 
-	if (smack_unconfined != NULL)
-		smack = smack_unconfined->smk_known;
+	if (smack_unconfined != NULL) {
+		smack = smk_find_label_name(smack_unconfined);
+		if (smack == NULL)
+			smack = smack_known_huh.smk_known;
+	}
 
 	asize = strlen(smack) + 1;
 
@@ -1808,7 +1819,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_import_entry(data, count);
+	skp = smk_get_label(data, count, true);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -2205,7 +2216,6 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
 	char *data = NULL;
-	const char *cp = NULL;
 	struct smack_known *skp;
 	struct smack_rule *sp;
 	struct list_head *rule_list;
@@ -2230,13 +2240,11 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 		goto free_out;
 	}
 
-	cp = smk_parse_smack(data, count);
-	if (IS_ERR(cp)) {
-		rc = PTR_ERR(cp);
+	skp = smk_get_label(data, count, false);
+	if (IS_ERR(skp)) {
+		rc = PTR_ERR(skp);
 		goto free_out;
 	}
-
-	skp = smk_find_entry(cp);
 	if (skp == NULL)
 		goto free_out;
 
@@ -2252,7 +2260,6 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 
 free_out:
 	kfree(data);
-	kfree(cp);
 	return rc;
 }
 
@@ -2315,23 +2322,25 @@ static const struct file_operations smk_change_rule_ops = {
 static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
-	struct smack_known *skp;
 	ssize_t rc = -EINVAL;
+	char *cp;
 	int asize;
 
 	if (*ppos != 0)
 		return 0;
 
 	if (smack_syslog_label == NULL)
-		skp = &smack_known_star;
-	else
-		skp = smack_syslog_label;
+		cp = smack_known_star.smk_known;
+	else {
+		cp = smk_find_label_name(smack_syslog_label);
+		if (cp == NULL)
+			cp = smack_known_huh.smk_known;
+	}
 
-	asize = strlen(skp->smk_known) + 1;
+	asize = strlen(cp) + 1;
 
 	if (cn >= asize)
-		rc = simple_read_from_buffer(buf, cn, ppos, skp->smk_known,
-						asize);
+		rc = simple_read_from_buffer(buf, cn, ppos, cp, asize);
 
 	return rc;
 }
@@ -2362,7 +2371,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (copy_from_user(data, buf, count) != 0)
 		rc = -EFAULT;
 	else {
-		skp = smk_import_entry(data, count);
+		skp = smk_get_label(data, count, true);
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else
-- 
2.1.0

[PATCH 5/8] smack: misc cleanups in preparation for a namespace patch

[Lukasz Pawelczyk]

This patch does some small miscellaneous cleanups and additions that
should not change the code behaviour in any way. Its only purpose is to
shape the code in a way that the smack namespace patches would be
smaller and easier to understand.

Changes:
- two small functions added
- one macro has been moved to a header
- minor code reformatting in several places for readability
- unnecessarily increasing string size has been fixed

This patch should not change the behaviour of the Smack in any way.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h        | 25 ++++++++++++++++++-
 security/smack/smack_access.c | 18 +++++++++-----
 security/smack/smack_lsm.c    | 58 ++++++++++++++++---------------------------
 3 files changed, 58 insertions(+), 43 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index fa32495..3818d19 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -229,6 +229,7 @@ struct smk_audit_info {
 	struct smack_audit_data sad;
 #endif
 };
+
 /*
  * These functions are in smack_lsm.c
  */
@@ -240,7 +241,7 @@ struct inode_smack *new_inode_smack(struct smack_known *);
 int smk_access_entry(char *, char *, struct list_head *);
 int smk_access(struct smack_known *, struct smack_known *,
 	       int, struct smk_audit_info *);
-int smk_tskacc(struct task_smack *, struct smack_known *,
+int smk_tskacc(struct task_struct *, struct smack_known *,
 	       u32, struct smk_audit_info *);
 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 struct smack_known *smack_from_secid(const u32);
@@ -287,6 +288,7 @@ extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 static inline int smk_inode_transmutable(const struct inode *isp)
 {
 	struct inode_smack *sip = isp->i_security;
+
 	return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 }
 
@@ -296,10 +298,31 @@ static inline int smk_inode_transmutable(const struct inode *isp)
 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 {
 	struct inode_smack *sip = isp->i_security;
+
 	return sip->smk_inode;
 }
 
 /*
+ * Present a pointer to the smack label entry in an inode blob for an exec.
+ */
+static inline struct smack_known *smk_of_exec(const struct inode *isp)
+{
+	struct inode_smack *sip = isp->i_security;
+
+	return sip->smk_task;
+}
+
+/*
+ * Present a pointer to the smack label entry in an inode blob for an mmap.
+ */
+static inline struct smack_known *smk_of_mmap(const struct inode *isp)
+{
+	struct inode_smack *sip = isp->i_security;
+
+	return sip->smk_mmap;
+}
+
+/*
  * Present a pointer to the smack label entry in an task blob.
  */
 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 3bf4cad..47a9c92 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -167,6 +167,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 		if (subject == &smack_known_hat)
 			goto out_audit;
 	}
+
 	/*
 	 * Beyond here an explicit relationship is required.
 	 * If the requested access is contained in the available
@@ -183,6 +184,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 		rc = -EACCES;
 		goto out_audit;
 	}
+
 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 	/*
 	 * Return a positive value if using bringup mode.
@@ -225,10 +227,10 @@ out_audit:
  * non zero otherwise. It allows that the task may have the capability
  * to override the rules.
  */
-int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
+int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
 	       u32 mode, struct smk_audit_info *a)
 {
-	struct smack_known *sbj_known = smk_of_task(tsp);
+	struct smack_known *sbj_known = smk_of_task_struct(task);
 	int may;
 	int rc;
 
@@ -237,13 +239,19 @@ int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
 	 */
 	rc = smk_access(sbj_known, obj_known, mode, NULL);
 	if (rc >= 0) {
+		struct task_smack *tsp;
+
 		/*
 		 * If there is an entry in the task's rule list
 		 * it can further restrict access.
 		 */
+		rcu_read_lock();
+		tsp = __task_cred(task)->security;
 		may = smk_access_entry(sbj_known->smk_known,
 				       obj_known->smk_known,
 				       &tsp->smk_rules);
+		rcu_read_unlock();
+
 		if (may < 0)
 			goto out_audit;
 		if ((mode & may) == mode)
@@ -280,9 +288,7 @@ out_audit:
 int smk_curacc(struct smack_known *obj_known,
 	       u32 mode, struct smk_audit_info *a)
 {
-	struct task_smack *tsp = current_security();
-
-	return smk_tskacc(tsp, obj_known, mode, a);
+	return smk_tskacc(current, obj_known, mode, a);
 }
 
 #ifdef CONFIG_AUDIT
@@ -456,7 +462,7 @@ char *smk_parse_smack(const char *string, int len)
 	int i;
 
 	if (len <= 0)
-		len = strlen(string) + 1;
+		len = strlen(string);
 
 	/*
 	 * Reserve a leading '-' as an indicator that
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4a197b6..bb74ca9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -383,8 +383,6 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 {
 	int rc;
 	struct smk_audit_info ad, *saip = NULL;
-	struct task_smack *tsp;
-	struct smack_known *tracer_known;
 
 	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
 		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
@@ -392,13 +390,12 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 		saip = &ad;
 	}
 
-	rcu_read_lock();
-	tsp = __task_cred(tracer)->security;
-	tracer_known = smk_of_task(tsp);
 
 	if ((mode & PTRACE_MODE_ATTACH) &&
 	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
 	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
+		struct smack_known *tracer_known = smk_of_task_struct(tracer);
+
 		if (tracer_known->smk_known == tracee_known->smk_known)
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
@@ -406,22 +403,18 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 		else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
 			rc = 0;
 		else
-			rc = -EACCES;
+			rc = -EPERM;
 
 		if (saip)
 			smack_log(tracer_known->smk_known,
 				  tracee_known->smk_known,
 				  0, rc, saip);
 
-		rcu_read_unlock();
 		return rc;
 	}
 
 	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
-	rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
-
-	rcu_read_unlock();
-	return rc;
+	return smk_tskacc(tracer, tracee_known, smk_ptrace_mode(mode), saip);
 }
 
 /*
@@ -440,9 +433,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
  */
 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 {
-	struct smack_known *skp;
-
-	skp = smk_of_task_struct(ctp);
+	struct smack_known *skp = smk_of_task_struct(ctp);
 
 	return smk_ptrace_rule_check(current, skp, mode, __func__);
 }
@@ -457,13 +448,9 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
  */
 static int smack_ptrace_traceme(struct task_struct *ptp)
 {
-	int rc;
-	struct smack_known *skp;
-
-	skp = smk_of_task(current_security());
+	struct smack_known *skp = smk_of_current();
 
-	rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
-	return rc;
+	return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
 }
 
 /**
@@ -1529,13 +1516,14 @@ static int smack_mmap_file(struct file *file,
 	if (file == NULL)
 		return 0;
 
+	tsp = current_security();
+	skp = smk_of_task(tsp);
 	isp = file_inode(file)->i_security;
-	if (isp->smk_mmap == NULL)
-		return 0;
 	mkp = isp->smk_mmap;
 
-	tsp = current_security();
-	skp = smk_of_current();
+	if (mkp == NULL)
+		return 0;
+
 	rc = 0;
 
 	rcu_read_lock();
@@ -3348,11 +3336,13 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 static int smack_unix_stream_connect(struct sock *sock,
 				     struct sock *other, struct sock *newsk)
 {
-	struct smack_known *skp;
-	struct smack_known *okp;
 	struct socket_smack *ssp = sock->sk_security;
 	struct socket_smack *osp = other->sk_security;
 	struct socket_smack *nsp = newsk->sk_security;
+	struct smack_known *skp_out = ssp->smk_out;
+	struct smack_known *okp_out = osp->smk_out;
+	struct smack_known *skp_in = ssp->smk_in;
+	struct smack_known *okp_in = osp->smk_in;
 	struct smk_audit_info ad;
 	int rc = 0;
 #ifdef CONFIG_AUDIT
@@ -3360,19 +3350,15 @@ static int smack_unix_stream_connect(struct sock *sock,
 #endif
 
 	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
-		skp = ssp->smk_out;
-		okp = osp->smk_in;
 #ifdef CONFIG_AUDIT
 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
 		smk_ad_setfield_u_net_sk(&ad, other);
 #endif
-		rc = smk_access(skp, okp, MAY_WRITE, &ad);
-		rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
+		rc = smk_access(skp_out, okp_in, MAY_WRITE, &ad);
+		rc = smk_bu_note("UDS connect", skp_out, okp_in, MAY_WRITE, rc);
 		if (rc == 0) {
-			okp = osp->smk_out;
-			skp = ssp->smk_in;
-			rc = smk_access(okp, skp, MAY_WRITE, &ad);
-			rc = smk_bu_note("UDS connect", okp, skp,
+			rc = smk_access(okp_out, skp_in, MAY_WRITE, &ad);
+			rc = smk_bu_note("UDS connect", okp_out, skp_in,
 						MAY_WRITE, rc);
 		}
 	}
@@ -3381,8 +3367,8 @@ static int smack_unix_stream_connect(struct sock *sock,
 	 * Cross reference the peer labels for SO_PEERSEC.
 	 */
 	if (rc == 0) {
-		nsp->smk_packet = ssp->smk_out;
-		ssp->smk_packet = osp->smk_out;
+		nsp->smk_packet = skp_out;
+		ssp->smk_packet = okp_out;
 	}
 
 	return rc;
-- 
2.1.0

[PATCH 6/8] smack: namespace groundwork

[Lukasz Pawelczyk]

This commit introduces several changes to Smack to prepare it for
namespace implementation. All the changes are related to namespaces.

Overview of the changes:
- Adds required data structures for mapped labels and functions to
  operate on them.
- Implements the proc interface /proc/$PID/smack_map that can be used for
  remapping of labels for a specific namespace. Also for checking the map.
- Modifies handling of special built-in labels. Detects them on import
  and assigns the same char* pointer regardless whether it's used in a
  normal or a mapped label. This way we can always compare them by ==
  instead of strcmp().
- Adds User namespace hooks implementation

This patch introduces both internal and user-space visible APIs to
handle namespaced labels and Smack namespaces but the behaviour of Smack
should not be changed. The APIs are there, but they have no impact yet.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 fs/proc/base.c                 |  57 ++++++
 include/linux/user_namespace.h |   5 +
 security/smack/Kconfig         |  10 +
 security/smack/Makefile        |   1 +
 security/smack/smack.h         |  42 +++-
 security/smack/smack_access.c  |  46 ++++-
 security/smack/smack_lsm.c     |  76 ++++++++
 security/smack/smack_ns.c      | 432 +++++++++++++++++++++++++++++++++++++++++
 8 files changed, 662 insertions(+), 7 deletions(-)
 create mode 100644 security/smack/smack_ns.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 093ca14..22dde1c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2529,6 +2529,57 @@ static const struct file_operations proc_setgroups_operations = {
 };
 #endif /* CONFIG_USER_NS */
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+static int proc_smack_map_open(struct inode *inode, struct file *file)
+{
+	struct user_namespace *ns = NULL;
+	struct task_struct *task;
+	struct seq_file *seq;
+	int ret = -EINVAL;
+
+	task = get_proc_task(inode);
+	if (task) {
+		rcu_read_lock();
+		ns = get_user_ns(task_cred_xxx(task, user_ns));
+		rcu_read_unlock();
+		put_task_struct(task);
+	}
+	if (!ns)
+		goto err;
+
+	ret = seq_open(file, &proc_smack_map_seq_operations);
+	if (ret)
+		goto err_put_ns;
+
+	seq = file->private_data;
+	seq->private = ns;
+
+	return 0;
+
+err_put_ns:
+	put_user_ns(ns);
+err:
+	return ret;
+}
+
+static int proc_smack_map_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+
+	put_user_ns(ns);
+	return seq_release(inode, file);
+}
+
+static const struct file_operations proc_smack_map_operations = {
+	.open		= proc_smack_map_open,
+	.write		= proc_smack_map_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_smack_map_release,
+};
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
 				struct pid *pid, struct task_struct *task)
 {
@@ -2637,6 +2688,9 @@ static const struct pid_entry tgid_base_stuff[] = {
 	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
 	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
 #endif
+#ifdef CONFIG_SECURITY_SMACK_NS
+	REG("smack_map",    S_IRUGO|S_IWUSR, proc_smack_map_operations),
+#endif
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	REG("timers",	  S_IRUGO, proc_timers_operations),
 #endif
@@ -2982,6 +3036,9 @@ static const struct pid_entry tid_base_stuff[] = {
 	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
 	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
 #endif
+#ifdef CONFIG_SECURITY_SMACK_NS
+	REG("smack_map",    S_IRUGO|S_IWUSR, proc_smack_map_operations),
+#endif
 };
 
 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index a9400cc..a8941a5 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -76,6 +76,11 @@ extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t,
 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 extern int proc_setgroups_show(struct seq_file *m, void *v);
 extern bool userns_may_setgroups(const struct user_namespace *ns);
+#ifdef CONFIG_SECURITY_SMACK_NS
+extern const struct seq_operations proc_smack_map_seq_operations;
+ssize_t proc_smack_map_write(struct file *file, const char __user *buf,
+			     size_t size, loff_t *ppos);
+#endif /* CONFIG_SECURITY_SMACK_NS */
 #else
 
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
diff --git a/security/smack/Kconfig b/security/smack/Kconfig
index 271adae..b19a7fb 100644
--- a/security/smack/Kconfig
+++ b/security/smack/Kconfig
@@ -40,3 +40,13 @@ config SECURITY_SMACK_NETFILTER
 	  This enables security marking of network packets using
 	  Smack labels.
 	  If you are unsure how to answer this question, answer N.
+
+config SECURITY_SMACK_NS
+	bool "Smack namespace"
+	depends on SECURITY_SMACK
+	depends on USER_NS
+	help
+	  This enables Smack namespace that makes it possible to map
+	  specific labels within user namespace (analogously to mapping
+	  UIDs) and to gain MAC capabilities over them.
+	  If you are unsure how to answer this question, answer N.
diff --git a/security/smack/Makefile b/security/smack/Makefile
index ee2ebd5..5faebd7 100644
--- a/security/smack/Makefile
+++ b/security/smack/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_SECURITY_SMACK) := smack.o
 
 smack-y := smack_lsm.o smack_access.o smackfs.o
 smack-$(CONFIG_SECURITY_SMACK_NETFILTER) += smack_netfilter.o
+smack-$(CONFIG_SECURITY_SMACK_NS) += smack_ns.o
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 3818d19..a53623a 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -21,6 +21,7 @@
 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/lsm_audit.h>
+#include <linux/user_namespace.h>
 
 /*
  * Smack labels were limited to 23 characters for a long time.
@@ -59,8 +60,36 @@ struct smack_known {
 	struct netlbl_lsm_secattr	smk_netlabel;	/* on wire labels */
 	struct list_head		smk_rules;	/* access rules */
 	struct mutex			smk_rules_lock;	/* lock for rules */
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct list_head		smk_mapped;	/* namespaced labels */
+	struct mutex			smk_mapped_lock;
+#endif /* CONFIG_SECURITY_SMACK_NS */
 };
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+
+/*
+ * User namespace security pointer content.
+ */
+struct smack_ns {
+	struct list_head		smk_mapped;	/* namespaced labels */
+	struct mutex			smk_mapped_lock;
+};
+
+/*
+ * A single entry for a namespaced/mapped label.
+ */
+struct smack_known_ns {
+	struct list_head	smk_list_known;
+	struct list_head	smk_list_ns;
+	struct user_namespace	*smk_ns;
+	char			*smk_mapped;
+	struct smack_known	*smk_unmapped;
+	bool			smk_allocated;
+};
+
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 /*
  * Maximum number of bytes for the levels in a CIPSO IP option.
  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
@@ -245,7 +274,7 @@ int smk_tskacc(struct task_struct *, struct smack_known *,
 	       u32, struct smk_audit_info *);
 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 struct smack_known *smack_from_secid(const u32);
-char *smk_parse_smack(const char *string, int len);
+char *smk_parse_smack(const char *string, int len, bool *allocated);
 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 struct smack_known *smk_import_entry(const char *, int);
 void smk_insert_entry(struct smack_known *skp);
@@ -254,6 +283,17 @@ char *smk_find_label_name(struct smack_known *skp);
 struct smack_known *smk_get_label(const char *string, int len, bool import);
 
 /*
+ * These functions are in smack_ns.c
+ */
+#ifdef CONFIG_SECURITY_SMACK_NS
+struct user_namespace *smk_find_mapped_ns(struct user_namespace *ns);
+struct smack_known_ns *smk_find_mapped(struct smack_known *skp,
+				       struct user_namespace *ns);
+struct smack_known *smk_find_unmapped(const char *string, int len,
+				      struct user_namespace *ns);
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
+/*
  * Shared data.
  */
 extern int smack_enabled;
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 47a9c92..c4d90d2 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -452,13 +452,16 @@ struct smack_known *smk_find_entry(const char *string)
 /**
  * smk_parse_smack - parse smack label from a text string
  * @string: a text string that might contain a Smack label
- * @len: the maximum size, or zero if it is NULL terminated.
+ * @len: the maximum size, or zero if it is NULL terminated
+ * @allocated: (out) indicates whether the return string has been
+ *             allocated and has to be freed with kfree() later
+ *             (built-in labels returned are not allocated)
  *
  * Returns a pointer to the clean label or an error code.
  */
-char *smk_parse_smack(const char *string, int len)
+char *smk_parse_smack(const char *string, int len, bool *allocated)
 {
-	char *smack;
+	char *smack = NULL;
 	int i;
 
 	if (len <= 0)
@@ -480,11 +483,33 @@ char *smk_parse_smack(const char *string, int len)
 	if (i == 0 || i >= SMK_LONGLABEL)
 		return ERR_PTR(-EINVAL);
 
+	/*
+	 * Look for special labels. This way we guarantee that we can compare
+	 * special labels in mapped entries by ==, without strcmp().
+	 */
+	if (len == 1 && !strcmp(string, smack_known_huh.smk_known))
+		smack = smack_known_huh.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_hat.smk_known))
+		smack = smack_known_hat.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_star.smk_known))
+		smack = smack_known_star.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_floor.smk_known))
+		smack = smack_known_floor.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_web.smk_known))
+		smack = smack_known_web.smk_known;
+
+	if (smack) {
+		*allocated = false;
+
+		return smack;
+	}
+
 	smack = kzalloc(i + 1, GFP_KERNEL);
 	if (smack == NULL)
 		return ERR_PTR(-ENOMEM);
 
 	strncpy(smack, string, i);
+	*allocated = true;
 
 	return smack;
 }
@@ -540,8 +565,9 @@ struct smack_known *smk_import_entry(const char *string, int len)
 	char *smack;
 	int slen;
 	int rc;
+	bool allocated;
 
-	smack = smk_parse_smack(string, len);
+	smack = smk_parse_smack(string, len, &allocated);
 	if (IS_ERR(smack))
 		return ERR_CAST(smack);
 
@@ -577,6 +603,10 @@ struct smack_known *smk_import_entry(const char *string, int len)
 	if (rc >= 0) {
 		INIT_LIST_HEAD(&skp->smk_rules);
 		mutex_init(&skp->smk_rules_lock);
+#ifdef CONFIG_SECURITY_SMACK_NS
+		INIT_LIST_HEAD(&skp->smk_mapped);
+		mutex_init(&skp->smk_mapped_lock);
+#endif /* CONFIG_SECURITY_SMACK_NS */
 		/*
 		 * Make sure that the entry is actually
 		 * filled before putting it on the list.
@@ -590,7 +620,8 @@ struct smack_known *smk_import_entry(const char *string, int len)
 	kfree(skp);
 	skp = ERR_PTR(rc);
 freeout:
-	kfree(smack);
+	if (allocated)
+		kfree(smack);
 unlockout:
 	mutex_unlock(&smack_known_lock);
 
@@ -649,16 +680,19 @@ char *smk_find_label_name(struct smack_known *skp)
 struct smack_known *smk_get_label(const char *string, int len, bool import)
 {
 	struct smack_known *skp;
+	bool allocated;
 	char *cp;
 
 	if (import) {
 		skp = smk_import_entry(string, len);
 	} else {
-		cp = smk_parse_smack(string, len);
+		cp = smk_parse_smack(string, len, &allocated);
 		if (IS_ERR(cp))
 			return ERR_CAST(cp);
 
 		skp = smk_find_entry(cp);
+		if (allocated)
+			kfree(cp);
 	}
 
 	return skp;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index bb74ca9..4ae9a9a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -41,6 +41,7 @@
 #include <linux/msg.h>
 #include <linux/shm.h>
 #include <linux/binfmts.h>
+#include <linux/user_namespace.h>
 #include "smack.h"
 
 #define TRANS_TRUE	"TRUE"
@@ -4165,6 +4166,53 @@ static void smack_audit_rule_free(void *vrule)
 
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+
+static inline int smack_userns_create(struct user_namespace *ns)
+{
+	struct smack_ns *snsp;
+
+	snsp = kzalloc(sizeof(*snsp), GFP_KERNEL);
+	if (snsp == NULL)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&snsp->smk_mapped);
+	mutex_init(&snsp->smk_mapped_lock);
+
+	ns->security = snsp;
+	return 0;
+}
+
+static inline void smack_userns_free(struct user_namespace *ns)
+{
+	struct smack_ns *snsp = ns->security;
+	struct smack_known *skp;
+	struct smack_known_ns *sknp, *n;
+
+	list_for_each_entry_safe(sknp, n, &snsp->smk_mapped, smk_list_ns) {
+		skp = sknp->smk_unmapped;
+
+		mutex_lock(&skp->smk_mapped_lock);
+		list_del_rcu(&sknp->smk_list_known);
+		if (sknp->smk_allocated)
+			kfree(sknp->smk_mapped);
+		kfree(sknp);
+		mutex_unlock(&skp->smk_mapped_lock);
+
+		list_del(&sknp->smk_list_ns);
+	}
+
+	kfree(snsp);
+}
+
+static inline int smack_userns_setns(struct nsproxy *nsproxy,
+				     struct user_namespace *ns)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 /**
  * smack_ismaclabel - check if xattr @name references a smack MAC label
  * @name: Full xattr name to check.
@@ -4376,6 +4424,13 @@ struct security_hook_list smack_hooks[] = {
 	LSM_HOOK_INIT(audit_rule_free, smack_audit_rule_free),
 #endif /* CONFIG_AUDIT */
 
+ /* Namespace hooks */
+#ifdef CONFIG_SECURITY_SMACK_NS
+	LSM_HOOK_INIT(userns_create, smack_userns_create),
+	LSM_HOOK_INIT(userns_free, smack_userns_free),
+	LSM_HOOK_INIT(userns_setns, smack_userns_setns),
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 	LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
 	LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
 	LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
@@ -4388,6 +4443,27 @@ struct security_hook_list smack_hooks[] = {
 
 static __init void init_smack_known_list(void)
 {
+#ifdef CONFIG_SECURITY_SMACK_NS
+	/*
+	 * Initialize mapped list locks
+	 */
+	mutex_init(&smack_known_huh.smk_mapped_lock);
+	mutex_init(&smack_known_hat.smk_mapped_lock);
+	mutex_init(&smack_known_floor.smk_mapped_lock);
+	mutex_init(&smack_known_star.smk_mapped_lock);
+	mutex_init(&smack_known_invalid.smk_mapped_lock);
+	mutex_init(&smack_known_web.smk_mapped_lock);
+	/*
+	 * Initialize mapped lists
+	 */
+	INIT_LIST_HEAD(&smack_known_huh.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_hat.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_star.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_floor.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_invalid.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_web.smk_mapped);
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 	/*
 	 * Initialize rule list locks
 	 */
diff --git a/security/smack/smack_ns.c b/security/smack/smack_ns.c
new file mode 100644
index 0000000..141a836
--- /dev/null
+++ b/security/smack/smack_ns.c
@@ -0,0 +1,432 @@
+/*
+ * Copyright (C) 2014 Samsung Electronics.
+ *
+ * Smack namespaces
+ *
+ * Author(s):
+ *    Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
+ *
+ * This program is free software, you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/file.h>
+#include <linux/ctype.h>
+#include <linux/rculist.h>
+#include <linux/seq_file.h>
+#include <linux/user_namespace.h>
+#include "smack.h"
+
+/**
+ * smk_find_mapped_ns - Finds a first namespace from this one through
+ * its parrents that has a map. This map is the effective map in this
+ * namespace.
+ * @ns: a user namespace for which we search for a mapped ns
+ *
+ * Returns a namespace that has a non-NULL map, or NULL if there is
+ * no mapped namespace.
+ *
+ * Can be effectively used to answer a question: "is there a Smack
+ * map for this namespace?"
+ */
+struct user_namespace *smk_find_mapped_ns(struct user_namespace *ns)
+{
+	struct user_namespace *user_ns = ns;
+
+	do {
+		struct smack_ns *sns = user_ns->security;
+
+		if (sns && !list_empty(&sns->smk_mapped))
+			break;
+
+		user_ns = user_ns->parent;
+	} while (user_ns);
+
+	return user_ns;
+}
+
+/**
+ * __smk_find_mapped - an internal version of smk_find_mapped
+ *                     that doesn't use smk_find_mapped_ns, but
+ *                     operates directly on the passed one.
+ */
+static struct smack_known_ns *__smk_find_mapped(struct smack_known *skp,
+						struct user_namespace *ns)
+{
+	struct smack_known_ns *sknp;
+
+	if (ns == NULL)
+		return NULL;
+
+	list_for_each_entry_rcu(sknp, &skp->smk_mapped, smk_list_known)
+		if (sknp->smk_ns == ns)
+			return sknp;
+
+	return NULL;
+}
+
+/**
+ * smk_find_mapped - Finds a mapped label on the smack_known's mapped list
+ * @skp: a label which mapped label we look for
+ * @ns: a user namespace the label we search for is assigned to
+ *
+ * Returns a pointer to the mapped label if one exists that is
+ * assigned to the specified user namespace or NULL if not found.
+ */
+struct smack_known_ns *smk_find_mapped(struct smack_known *skp,
+				       struct user_namespace *ns)
+{
+	struct user_namespace *user_ns = smk_find_mapped_ns(ns);
+
+	return __smk_find_mapped(skp, user_ns);
+}
+
+/**
+ * __smk_find_unmapped - an internal version of smk_find_unmapped
+ *                       that doesn't use smk_find_mapped_ns, but
+ *                       operates directly on the passed one.
+ */
+static struct smack_known *__smk_find_unmapped(const char *string, int len,
+					       struct user_namespace *ns)
+{
+	struct smack_ns *snsp;
+	struct smack_known *skp = NULL;
+	struct smack_known_ns *sknp;
+	char *smack;
+	bool allocated = false;
+
+	if (ns == NULL)
+		return NULL;
+
+	snsp = ns->security;
+
+	smack = smk_parse_smack(string, len, &allocated);
+	if (IS_ERR(smack))
+		return ERR_CAST(smack);
+
+	list_for_each_entry_rcu(sknp, &snsp->smk_mapped, smk_list_ns) {
+		if (strcmp(smack, sknp->smk_mapped) == 0) {
+			skp = sknp->smk_unmapped;
+			break;
+		}
+	}
+
+	if (allocated)
+		kfree(smack);
+	return skp;
+}
+
+/**
+ * smk_find_unmapped - Finds an original label by a mapped label string
+ *                     and the namespace it could be mapped in
+ * @string: a name of a mapped label we look for
+ * @len: the string size, or zero if it is NULL terminated.
+ * @ns: a namespace the looked for label should be mapped in
+ *
+ * Returns a smack_known label that is mapped as 'string' in 'ns',
+ * NULL if not found or an error code.
+ */
+struct smack_known *smk_find_unmapped(const char *string, int len,
+				      struct user_namespace *ns)
+{
+	struct user_namespace *user_ns = smk_find_mapped_ns(ns);
+
+	return __smk_find_unmapped(string, len, user_ns);
+}
+
+/**
+ * smk_import_mapped - Imports a mapped label effectively creating a mapping.
+ * @skp: a label we map
+ * @ns: a user namespace this label will be mapped in
+ * @string: a text string of the mapped label
+ * @len: the maximum size, or zero if it is NULL terminanted
+ *
+ * Returns a pointer to the mapped label entry or an error code.
+ *
+ * The mapped label will be added to 2 lists:
+ *   - a list of mapped labels of skp
+ *   - a list of labels mapped in ns
+ */
+static struct smack_known_ns *smk_import_mapped(struct smack_known *skp,
+						struct user_namespace *ns,
+						const char *string, int len)
+{
+	struct smack_ns *snsp = ns->security;
+	struct smack_known_ns *sknp;
+	char *mapped;
+	bool allocated;
+
+	/* Mapping init_user_ns is against the design and pointless */
+	if (ns == &init_user_ns)
+		return ERR_PTR(-EBADR);
+
+	mapped = smk_parse_smack(string, len, &allocated);
+	if (IS_ERR(mapped))
+		return ERR_CAST(mapped);
+
+	mutex_lock(&skp->smk_mapped_lock);
+
+	/*
+	 * Don't allow one<->many mappings in namespace, rename.
+	 * This code won't get triggered for now as trying to assign
+	 * a duplicate is forbidden in proc_smack_map_write().
+	 * Leaving this as this function might be also used elsewhere.
+	 */
+	sknp = smk_find_mapped(skp, ns);
+	if (sknp != NULL) {
+		if (sknp->smk_allocated)
+			kfree(sknp->smk_mapped);
+		sknp->smk_mapped = mapped;
+		sknp->smk_allocated = allocated;
+		goto unlockout;
+	}
+
+	sknp = kzalloc(sizeof(*sknp), GFP_KERNEL);
+	if (sknp == NULL) {
+		sknp = ERR_PTR(-ENOMEM);
+		if (allocated)
+			kfree(mapped);
+		goto unlockout;
+	}
+
+	sknp->smk_ns = ns;
+	sknp->smk_mapped = mapped;
+	sknp->smk_allocated = allocated;
+	sknp->smk_unmapped = skp;
+	list_add_rcu(&sknp->smk_list_known, &skp->smk_mapped);
+
+	mutex_lock(&snsp->smk_mapped_lock);
+	list_add_rcu(&sknp->smk_list_ns, &snsp->smk_mapped);
+	mutex_unlock(&snsp->smk_mapped_lock);
+
+unlockout:
+	mutex_unlock(&skp->smk_mapped_lock);
+
+	return sknp;
+}
+
+static void *proc_smack_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct smack_known *skp;
+	struct user_namespace *ns = seq->private;
+	loff_t counter = *pos;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(skp, &smack_known_list, list)
+		if (smk_find_mapped(skp, ns) && counter-- == 0)
+			return skp;
+
+	return NULL;
+}
+
+static void proc_smack_map_seq_stop(struct seq_file *seq, void *v)
+{
+	rcu_read_unlock();
+}
+
+static void *proc_smack_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct smack_known *skp = v;
+	struct user_namespace *ns = seq->private;
+
+	list_for_each_entry_continue_rcu(skp, &smack_known_list, list) {
+		if (smk_find_mapped(skp, ns)) {
+			(*pos)++;
+			return skp;
+		}
+	}
+
+	return NULL;
+}
+
+static int proc_smack_map_seq_show(struct seq_file *seq, void *v)
+{
+	struct smack_known *skp = v;
+	struct user_namespace *ns = seq->private;
+	struct smack_known_ns *sknp;
+
+	/*
+	 * QUESTION: linux-api
+	 * What to print when in init_map_ns where the map is empty
+	 * effectively meaning identity? Unfortunately it's impossible
+	 * to show identity in this syntax without printing all the labels.
+	 */
+	if (smk_find_mapped_ns(ns) == NULL) {
+		seq_puts("This namespace is not mapped.\n");
+	} else {
+		sknp = smk_find_mapped(skp, ns);
+		if (sknp)
+			seq_printf(seq, "%s -> %s\n",
+				   skp->smk_known, sknp->smk_mapped);
+	}
+
+	return 0;
+}
+
+const struct seq_operations proc_smack_map_seq_operations = {
+	.start = proc_smack_map_seq_start,
+	.stop = proc_smack_map_seq_stop,
+	.next = proc_smack_map_seq_next,
+	.show = proc_smack_map_seq_show,
+};
+
+static DEFINE_MUTEX(smk_map_mutex);
+
+static bool mapping_permitted(const struct file *file,
+			      struct user_namespace *user_ns)
+{
+	/*
+	 * Do not allow mapping own label. This is in contrast to user
+	 * namespace where you can always map your own UID. In Smack having
+	 * administrative privileges over your own label (which Smack
+	 * namespace effectively gives you) is not equivalent to user
+	 * namespace. E.g. things like setting exec/transmute labels that
+	 * otherwise would be denied. Hence no own_label param here.
+	 */
+
+	/*
+	 * Adjusting namespace settings requires capabilities on the target.
+	 */
+	if (!file_ns_capable(file, user_ns, CAP_MAC_ADMIN))
+		return false;
+
+	/*
+	 * And it requires capabilities in the parent.
+	 *
+	 * If the Smack namespace was properly hierarchical the user_ns to
+	 * check against could be 'user_ns->parent'. Right now because of
+	 * security concerns only privileged initial namespace is allowed
+	 * to fill the map. For a hierarchical namespaces one would
+	 * implement mapping (in the child namespaces) of only mapped labels
+	 * (in parent namespace) and change '&init_user_ns' to
+	 * 'user_ns->parent'. This will be added in the future.
+	 */
+	if (smack_ns_privileged(&init_user_ns, CAP_MAC_ADMIN) &&
+	    file_ns_capable(file, &init_user_ns, CAP_MAC_ADMIN))
+		return true;
+
+	return false;
+}
+
+ssize_t proc_smack_map_write(struct file *file, const char __user *buf,
+			     size_t size, loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	struct user_namespace *seq_ns = seq_user_ns(seq);
+	struct smack_known *skp;
+	struct smack_known_ns *sknp;
+	unsigned long page = 0;
+	char *kbuf, *pos, *next_line, *tok[2];
+	ssize_t ret;
+	int i;
+
+	/* Mapping labels for the init ns makes no sense */
+	if (ns == &init_user_ns)
+		return -EBADR;
+
+	if ((seq_ns != ns) && (seq_ns != ns->parent))
+		return -EPERM;
+
+	mutex_lock(&smk_map_mutex);
+
+	ret = -EPERM;
+	if (!mapping_permitted(file, ns))
+		goto out;
+
+	/* Get a buffer */
+	ret = ENOMEM;
+	page = __get_free_page(GFP_TEMPORARY);
+	if (!page)
+		goto out;
+	kbuf = (char *)page;
+
+	/* Only allow <= page size writes at the beginning of the file */
+	ret = -EINVAL;
+	if ((*ppos != 0) || (size >= PAGE_SIZE))
+		goto out;
+
+	/* Slurp in the user data */
+	ret = -EFAULT;
+	if (copy_from_user(kbuf, buf, size))
+		goto out;
+	kbuf[size] = '\0';
+
+	/* Parse the user data */
+	pos = kbuf;
+
+	for (; pos; pos = next_line) {
+		ret = -EINVAL;
+
+		/* Find the end of line and ensure I don't look past it */
+		next_line = strchr(pos, '\n');
+		if (next_line) {
+			*next_line = '\0';
+			next_line++;
+			if (*next_line == '\0')
+				next_line = NULL;
+		}
+
+		/* Find tokens in line */
+		for (i = 0; i < 2; ++i) {
+			while (isspace(*pos))
+				*(pos++) = '\0';
+
+			/* unexpected end of file */
+			if (*pos == '\0')
+				goto out;
+
+			tok[i] = pos;
+
+			/* find the end of the token */
+			while (*pos != '\0' && !isspace(*pos))
+				++pos;
+		}
+
+		/* NUL terminate the last token if not EOL */
+		while (isspace(*pos))
+			*(pos++) = '\0';
+
+		/* there should not be any trailing data */
+		if (*pos != '\0')
+			goto out;
+
+		/* do not allow to map 2 different labels to one name */
+		skp = __smk_find_unmapped(tok[1], 0, ns);
+		if (IS_ERR(skp)) {
+			ret = PTR_ERR(skp);
+			goto out;
+		}
+		if (skp != NULL) {
+			ret = -EEXIST;
+			goto out;
+		}
+
+		skp = smk_import_entry(tok[0], 0);
+		if (IS_ERR(skp)) {
+			ret = PTR_ERR(skp);
+			goto out;
+		}
+
+		/* do not allow remapping */
+		ret = -EEXIST;
+		if (__smk_find_mapped(skp, ns))
+			goto out;
+
+		sknp = smk_import_mapped(skp, ns, tok[1], 0);
+		if (IS_ERR(sknp)) {
+			ret = PTR_ERR(sknp);
+			goto out;
+		}
+	}
+
+	ret = size;
+
+out:
+	mutex_unlock(&smk_map_mutex);
+	if (page)
+		free_page(page);
+
+	return ret;
+}
-- 
2.1.0

[PATCH 7/8] smack: namespace implementation

[Lukasz Pawelczyk]

This commit uses all the changes introduced in "namespace groundwork"
and previous preparation patches and makes smack aware of its namespace
and mapped labels.

It modifies the following functions to be namespace aware:
- smk_access
- smk_find_label_name
- smk_get_label

And all functions that use them (e.g. smk_tskacc).

It also adds another function that is used throughout Smack LSM hooks:
- smk_labels_valid - it checks whether both, subject and object labels
  are properly mapped in a namespace where they are to be used. This
  function is used mostly together with a capability check when there is
  no proper access check that usually checks for that.

All the Smack LSM hooks have been adapted to be namespace aware.

The capabilities (CAP_MAC_ADMIN, CAP_MAC_OVERRIDE) has been allowed in
the namespace for few cases. Check the documentation for the details.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h        |  61 ++++++-
 security/smack/smack_access.c |  99 ++++++++++--
 security/smack/smack_lsm.c    | 358 ++++++++++++++++++++++++++++++------------
 security/smack/smack_ns.c     |  41 ++++-
 security/smack/smackfs.c      |  57 ++++---
 5 files changed, 474 insertions(+), 142 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index a53623a..b8ed852 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -104,6 +104,7 @@ struct superblock_smack {
 	struct smack_known	*smk_floor;
 	struct smack_known	*smk_hat;
 	struct smack_known	*smk_default;
+	struct user_namespace	*smk_ns;
 	int			smk_initialized;
 };
 
@@ -111,6 +112,7 @@ struct socket_smack {
 	struct smack_known	*smk_out;	/* outbound label */
 	struct smack_known	*smk_in;	/* inbound label */
 	struct smack_known	*smk_packet;	/* TCP peer label */
+	struct user_namespace	*smk_ns;	/* user namespace */
 };
 
 /*
@@ -131,6 +133,14 @@ struct task_smack {
 	struct mutex		smk_rules_lock;	/* lock for the rules */
 };
 
+/*
+ * Used for IPC objects (sem, shm, etc)
+ */
+struct ipc_smack {
+	struct smack_known	*smk_known;	/* label for access control */
+	struct user_namespace	*smk_ns;	/* user namespace */
+};
+
 #define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */
 #define	SMK_INODE_TRANSMUTE	0x02	/* directory is transmuting */
 #define	SMK_INODE_CHANGED	0x04	/* smack was transmuted */
@@ -269,18 +279,20 @@ struct inode_smack *new_inode_smack(struct smack_known *);
  */
 int smk_access_entry(char *, char *, struct list_head *);
 int smk_access(struct smack_known *, struct smack_known *,
-	       int, struct smk_audit_info *);
+	       struct user_namespace *, int, struct smk_audit_info *);
 int smk_tskacc(struct task_struct *, struct smack_known *,
+	       struct user_namespace *, u32, struct smk_audit_info *);
+int smk_curacc(struct smack_known *, struct user_namespace *,
 	       u32, struct smk_audit_info *);
-int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 struct smack_known *smack_from_secid(const u32);
 char *smk_parse_smack(const char *string, int len, bool *allocated);
 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 struct smack_known *smk_import_entry(const char *, int);
 void smk_insert_entry(struct smack_known *skp);
 struct smack_known *smk_find_entry(const char *);
-char *smk_find_label_name(struct smack_known *skp);
-struct smack_known *smk_get_label(const char *string, int len, bool import);
+char *smk_find_label_name(struct smack_known *skp, struct user_namespace *ns);
+struct smack_known *smk_get_label(const char *string, int len, bool import,
+				  struct user_namespace *ns);
 
 /*
  * These functions are in smack_ns.c
@@ -291,6 +303,15 @@ struct smack_known_ns *smk_find_mapped(struct smack_known *skp,
 				       struct user_namespace *ns);
 struct smack_known *smk_find_unmapped(const char *string, int len,
 				      struct user_namespace *ns);
+bool smk_labels_valid(struct smack_known *sbj, struct smack_known *obj,
+		      struct user_namespace *ns);
+#else
+static inline bool smk_labels_valid(struct smack_known *sbj,
+				    struct smack_known *obj,
+				    struct user_namespace *ns)
+{
+	return true;
+}
 #endif /* CONFIG_SECURITY_SMACK_NS */
 
 /*
@@ -397,18 +418,48 @@ static inline struct smack_known *smk_of_current(void)
 }
 
 /*
+ * Present a pointer to the user namespace entry in an task blob.
+ */
+static inline
+struct user_namespace *ns_of_task_struct(const struct task_struct *t)
+{
+	struct user_namespace *ns;
+
+	rcu_read_lock();
+	ns = __task_cred(t)->user_ns;
+	rcu_read_unlock();
+
+	return ns;
+}
+
+/*
+ * Present a pointer to the user namespace entry in the current task blob.
+ */
+static inline struct user_namespace *ns_of_current(void)
+{
+	return current->cred->user_ns;
+}
+
+/*
  * Internal smack capability check complimentary to the
  * set of kernel capable() and has_capability() functions
  *
  * For a capability in smack related checks to be effective it needs to:
  * - have empty onlycap or the current label be the same as onlycap
- * - be in the initial user ns
+ * - be in the initial user ns or have a filled map in the child ns
  */
 static inline int smack_capability_allowed(struct smack_known *skp,
 					   struct user_namespace *user_ns)
 {
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct smack_ns *sns = user_ns->security;
+
+	if (user_ns != &init_user_ns && list_empty(&sns->smk_mapped))
+		return 0;
+#else
 	if (user_ns != &init_user_ns)
 		return 0;
+#endif /* CONFIG_SECURITY_SMACK_NS */
 
 	if (smack_onlycap != NULL && smack_onlycap != skp)
 		return 0;
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index c4d90d2..600e95c 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
+#include <linux/user_namespace.h>
 #include "smack.h"
 
 struct smack_known smack_known_huh = {
@@ -113,6 +114,7 @@ int smk_access_entry(char *subject_label, char *object_label,
  * smk_access - determine if a subject has a specific access to an object
  * @subject: a pointer to the subject's Smack label entry
  * @object: a pointer to the object's Smack label entry
+ * @ns: user namespace to check against (usually subject's)
  * @request: the access requested, in "MAY" format
  * @a : a pointer to the audit data
  *
@@ -123,10 +125,34 @@ int smk_access_entry(char *subject_label, char *object_label,
  * Smack labels are shared on smack_list
  */
 int smk_access(struct smack_known *subject, struct smack_known *object,
-	       int request, struct smk_audit_info *a)
+	       struct user_namespace *ns, int request, struct smk_audit_info *a)
 {
 	int may = MAY_NOT;
 	int rc = 0;
+	char *subject_label = subject->smk_known;
+	char *object_label = object->smk_known;
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct smack_known_ns *sknp;
+	struct smack_known_ns *oknp;
+
+	/*
+	 * For the namespaced case we need to check whether the labels
+	 * are mapped. If not, refuse. If yes check the builtin rules
+	 * on the mapped label strings so the builtin labels can
+	 * work properly inside the namespace.
+	 */
+	if (smk_find_mapped_ns(ns)) {
+		sknp = smk_find_mapped(subject, ns);
+		oknp = smk_find_mapped(object, ns);
+		if (!sknp || !oknp) {
+			rc = -EACCES;
+			goto out_audit;
+		}
+
+		subject_label = sknp->smk_mapped;
+		object_label = oknp->smk_mapped;
+	}
+#endif
 
 	/*
 	 * Hardcoded comparisons.
@@ -134,7 +160,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	/*
 	 * A star subject can't access any object.
 	 */
-	if (subject == &smack_known_star) {
+	if (subject_label == smack_known_star.smk_known) {
 		rc = -EACCES;
 		goto out_audit;
 	}
@@ -143,18 +169,19 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	 * Tasks cannot be assigned the internet label.
 	 * An internet subject can access any object.
 	 */
-	if (object == &smack_known_web || subject == &smack_known_web)
+	if (object_label == smack_known_web.smk_known ||
+	    subject_label == smack_known_web.smk_known)
 		goto out_audit;
 	/*
 	 * A star object can be accessed by any subject.
 	 */
-	if (object == &smack_known_star)
+	if (object_label == smack_known_star.smk_known)
 		goto out_audit;
 	/*
 	 * An object can be accessed in any way by a subject
 	 * with the same label.
 	 */
-	if (subject->smk_known == object->smk_known)
+	if (subject_label == object_label)
 		goto out_audit;
 	/*
 	 * A hat subject can read or lock any object.
@@ -162,9 +189,9 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	 */
 	if ((request & MAY_ANYREAD) == request ||
 	    (request & MAY_LOCK) == request) {
-		if (object == &smack_known_floor)
+		if (object_label == smack_known_floor.smk_known)
 			goto out_audit;
-		if (subject == &smack_known_hat)
+		if (subject_label == smack_known_hat.smk_known)
 			goto out_audit;
 	}
 
@@ -174,6 +201,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	 * access (e.g. read is included in readwrite) it's
 	 * good. A negative response from smk_access_entry()
 	 * indicates there is no entry for this pair.
+	 * For this check we need real, not mapped labels.
 	 */
 	rcu_read_lock();
 	may = smk_access_entry(subject->smk_known, object->smk_known,
@@ -219,6 +247,7 @@ out_audit:
  * smk_tskacc - determine if a task has a specific access to an object
  * @tsp: a pointer to the subject's task
  * @obj_known: a pointer to the object's label entry
+ * @obj_ns: an object's namespace to check the caps against
  * @mode: the access requested, in "MAY" format
  * @a : common audit data
  *
@@ -228,16 +257,18 @@ out_audit:
  * to override the rules.
  */
 int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
-	       u32 mode, struct smk_audit_info *a)
+	       struct user_namespace *obj_ns, u32 mode,
+	       struct smk_audit_info *a)
 {
 	struct smack_known *sbj_known = smk_of_task_struct(task);
+	struct user_namespace *sbj_ns = ns_of_task_struct(task);
 	int may;
 	int rc;
 
 	/*
 	 * Check the global rule list
 	 */
-	rc = smk_access(sbj_known, obj_known, mode, NULL);
+	rc = smk_access(sbj_known, obj_known, sbj_ns, mode, NULL);
 	if (rc >= 0) {
 		struct task_smack *tsp;
 
@@ -261,8 +292,10 @@ int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
 
 	/*
 	 * Allow for priviliged to override policy.
+	 * Either in init_ns or when both labels are mapped.
 	 */
-	if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
+	if (rc != 0 && smk_labels_valid(sbj_known, obj_known, sbj_ns)
+	    && smack_has_ns_privilege(task, obj_ns, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 out_audit:
@@ -277,6 +310,7 @@ out_audit:
 /**
  * smk_curacc - determine if current has a specific access to an object
  * @obj_known: a pointer to the object's Smack label entry
+ * @obj_ns: an object's namespace to check the caps against
  * @mode: the access requested, in "MAY" format
  * @a : common audit data
  *
@@ -285,10 +319,10 @@ out_audit:
  * non zero otherwise. It allows that current may have the capability
  * to override the rules.
  */
-int smk_curacc(struct smack_known *obj_known,
+int smk_curacc(struct smack_known *obj_known, struct user_namespace *obj_ns,
 	       u32 mode, struct smk_audit_info *a)
 {
-	return smk_tskacc(current, obj_known, mode, a);
+	return smk_tskacc(current, obj_known, obj_ns, mode, a);
 }
 
 #ifdef CONFIG_AUDIT
@@ -656,14 +690,32 @@ struct smack_known *smack_from_secid(const u32 secid)
 }
 
 /**
- * smk_find_label_name - A helper to get a string value of a label
+ * smk_find_label_name - A helper to get a string value of either a label or a
+ *                       mapped label when inside a namespace
  * @skp: a label we want a string value from
+ * @ns: namespace against which we want to get the value
  *
  * Returns a pointer to a label name or NULL if label name not found.
  */
-char *smk_find_label_name(struct smack_known *skp)
+char *smk_find_label_name(struct smack_known *skp, struct user_namespace *ns)
 {
-	return skp->smk_known;
+	char *name = NULL;
+
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct smack_known_ns *sknp;
+
+	if (smk_find_mapped_ns(ns)) {
+		sknp = smk_find_mapped(skp, ns);
+		if (sknp != NULL)
+			name = sknp->smk_mapped;
+	} else {
+		name = skp->smk_known;
+	}
+#else
+	name = skp->smk_known;
+#endif
+
+	return name;
 }
 
 /**
@@ -672,17 +724,32 @@ char *smk_find_label_name(struct smack_known *skp)
  * @string: a name of a label we look for or want to import
  * @len: the string size, or zero if it is NULL terminated
  * @import: whether we should import the label if not found
+ * @ns: a namespace the looked for label should be in
  *
  * Returns a smack_known label that is either imported or found.
  * NULL if label not found (only when import == false).
  * Error code otherwise.
  */
-struct smack_known *smk_get_label(const char *string, int len, bool import)
+struct smack_known *smk_get_label(const char *string, int len, bool import,
+				  struct user_namespace *ns)
 {
 	struct smack_known *skp;
 	bool allocated;
 	char *cp;
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+	if (smk_find_mapped_ns(ns)) {
+		skp = smk_find_unmapped(string, len, ns);
+
+		/* Label not found but we can't import in namespaces */
+		if (skp == NULL && import)
+			skp = ERR_PTR(-EBADR);
+
+		/* will also return error codes from smk_find_unmapped() */
+		return skp;
+	}
+#endif
+
 	if (import) {
 		skp = smk_import_entry(string, len);
 	} else {
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4ae9a9a..af0a5fd 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -373,6 +373,7 @@ static inline unsigned int smk_ptrace_mode(unsigned int mode)
  * smk_ptrace_rule_check - helper for ptrace access
  * @tracer: tracer process
  * @tracee_known: label entry of the process that's about to be traced
+ * @tracee_ns: a tracee's namespace to check the caps against
  * @mode: ptrace attachment mode (PTRACE_MODE_*)
  * @func: name of the function that called us, used for audit
  *
@@ -380,6 +381,7 @@ static inline unsigned int smk_ptrace_mode(unsigned int mode)
  */
 static int smk_ptrace_rule_check(struct task_struct *tracer,
 				 struct smack_known *tracee_known,
+				 struct user_namespace *tracee_ns,
 				 unsigned int mode, const char *func)
 {
 	int rc;
@@ -391,21 +393,28 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 		saip = &ad;
 	}
 
-
 	if ((mode & PTRACE_MODE_ATTACH) &&
 	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
 	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
 		struct smack_known *tracer_known = smk_of_task_struct(tracer);
+		struct user_namespace *tracer_ns = ns_of_task_struct(tracer);
+
+		if (!smk_labels_valid(tracer_known, tracee_known, tracer_ns)) {
+			rc = -EACCES;
+			goto out;
+		}
 
 		if (tracer_known->smk_known == tracee_known->smk_known)
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
 			rc = -EACCES;
-		else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
+		else if (smack_has_ns_privilege(tracer, tracee_ns,
+						CAP_SYS_PTRACE))
 			rc = 0;
 		else
 			rc = -EPERM;
 
+out:
 		if (saip)
 			smack_log(tracer_known->smk_known,
 				  tracee_known->smk_known,
@@ -415,7 +424,8 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 	}
 
 	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
-	return smk_tskacc(tracer, tracee_known, smk_ptrace_mode(mode), saip);
+	return smk_tskacc(tracer, tracee_known, tracee_ns,
+			  smk_ptrace_mode(mode), saip);
 }
 
 /*
@@ -435,8 +445,9 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 {
 	struct smack_known *skp = smk_of_task_struct(ctp);
+	struct user_namespace *ns = ns_of_task_struct(ctp);
 
-	return smk_ptrace_rule_check(current, skp, mode, __func__);
+	return smk_ptrace_rule_check(current, skp, ns, mode, __func__);
 }
 
 /**
@@ -450,8 +461,10 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 static int smack_ptrace_traceme(struct task_struct *ptp)
 {
 	struct smack_known *skp = smk_of_current();
+	struct user_namespace *ns = ns_of_current();
 
-	return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
+	return smk_ptrace_rule_check(ptp, skp, ns, PTRACE_MODE_ATTACH,
+				     __func__);
 }
 
 /**
@@ -498,6 +511,7 @@ static int smack_sb_alloc_security(struct super_block *sb)
 	sbsp->smk_default = &smack_known_floor;
 	sbsp->smk_floor = &smack_known_floor;
 	sbsp->smk_hat = &smack_known_hat;
+	sbsp->smk_ns = get_user_ns(&init_user_ns);
 	/*
 	 * smk_initialized will be zero from kzalloc.
 	 */
@@ -513,6 +527,9 @@ static int smack_sb_alloc_security(struct super_block *sb)
  */
 static void smack_sb_free_security(struct super_block *sb)
 {
+	struct superblock_smack *sbsp = sb->s_security;
+
+	put_user_ns(sbsp->smk_ns);
 	kfree(sb->s_security);
 	sb->s_security = NULL;
 }
@@ -579,6 +596,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 	struct superblock_smack *sp = sb->s_security;
 	struct inode_smack *isp;
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	char *op;
 	char *commap;
 	int transmute = 0;
@@ -596,7 +614,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
 			op += strlen(SMK_FSHAT);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_hat = skp;
@@ -604,7 +622,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
 			op += strlen(SMK_FSFLOOR);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_floor = skp;
@@ -613,7 +631,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		} else if (strncmp(op, SMK_FSDEFAULT,
 				   strlen(SMK_FSDEFAULT)) == 0) {
 			op += strlen(SMK_FSDEFAULT);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_default = skp;
@@ -621,7 +639,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
 			op += strlen(SMK_FSROOT);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -629,7 +647,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
 			op += strlen(SMK_FSTRANS);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -638,7 +656,12 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		}
 	}
 
-	if (!smack_privileged(CAP_MAC_ADMIN)) {
+	/*
+	 * Check for non-privileged case. If current is inside the namespace
+	 * and the it has privileges the validity of labels has already been
+	 * checked during smk_get_label()
+	 */
+	if (!smack_ns_privileged(ns, CAP_MAC_ADMIN)) {
 		/*
 		 * Unprivileged mounts don't get to specify Smack values.
 		 */
@@ -651,6 +674,13 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		sp->smk_root = skp;
 		sp->smk_default = skp;
 	}
+
+	/*
+	 * Set the superblock namespace from a mounting process
+	 */
+	put_user_ns(sp->smk_ns);
+	sp->smk_ns = get_user_ns(ns);
+
 	/*
 	 * Initialize the root inode.
 	 */
@@ -685,7 +715,7 @@ static int smack_sb_statfs(struct dentry *dentry)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
+	rc = smk_curacc(sbp->smk_floor, sbp->smk_ns, MAY_READ, &ad);
 	rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
 	return rc;
 }
@@ -705,6 +735,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	struct inode *inode = file_inode(bprm->file);
 	struct task_smack *bsp = bprm->cred->security;
 	struct inode_smack *isp;
+	struct user_namespace *ns = ns_of_current();
 	int rc;
 
 	if (bprm->cred_prepared)
@@ -714,6 +745,13 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
 		return 0;
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+	/* one label version of smk_labels_valid() */
+	if (smk_find_mapped_ns(ns) &&
+	    smk_find_mapped(isp->smk_task, ns) == NULL)
+		return -EACCES;
+#endif
+
 	if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
 		struct task_struct *tracer;
 		rc = 0;
@@ -721,9 +759,8 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 		rcu_read_lock();
 		tracer = ptrace_parent(current);
 		if (likely(tracer != NULL))
-			rc = smk_ptrace_rule_check(tracer,
-						   isp->smk_task,
-						   PTRACE_MODE_ATTACH,
+			rc = smk_ptrace_rule_check(tracer, isp->smk_task,
+						   ns, PTRACE_MODE_ATTACH,
 						   __func__);
 		rcu_read_unlock();
 
@@ -864,6 +901,7 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 			    struct dentry *new_dentry)
 {
 	struct smack_known *isp;
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -871,13 +909,13 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
 
 	isp = smk_of_inode(d_backing_inode(old_dentry));
-	rc = smk_curacc(isp, MAY_WRITE, &ad);
+	rc = smk_curacc(isp, ns, MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_WRITE, rc);
 
 	if (rc == 0 && d_is_positive(new_dentry)) {
 		isp = smk_of_inode(d_backing_inode(new_dentry));
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
-		rc = smk_curacc(isp, MAY_WRITE, &ad);
+		rc = smk_curacc(isp, ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_WRITE, rc);
 	}
 
@@ -895,6 +933,7 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *ip = d_backing_inode(dentry);
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -904,7 +943,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 	/*
 	 * You need write access to the thing you're unlinking
 	 */
-	rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(ip), ns, MAY_WRITE, &ad);
 	rc = smk_bu_inode(ip, MAY_WRITE, rc);
 	if (rc == 0) {
 		/*
@@ -912,7 +951,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 		 */
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 		smk_ad_setfield_u_fs_inode(&ad, dir);
-		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(dir), ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
 	}
 	return rc;
@@ -928,6 +967,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
  */
 static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -937,7 +977,8 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 	/*
 	 * You need write access to the thing you're removing
 	 */
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), ns,
+			MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	if (rc == 0) {
 		/*
@@ -945,7 +986,7 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 		 */
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 		smk_ad_setfield_u_fs_inode(&ad, dir);
-		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(dir), ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
 	}
 
@@ -969,21 +1010,22 @@ static int smack_inode_rename(struct inode *old_inode,
 			      struct inode *new_inode,
 			      struct dentry *new_dentry)
 {
-	int rc;
 	struct smack_known *isp;
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
+	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
 
 	isp = smk_of_inode(d_backing_inode(old_dentry));
-	rc = smk_curacc(isp, MAY_READWRITE, &ad);
+	rc = smk_curacc(isp, ns, MAY_READWRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_READWRITE, rc);
 
 	if (rc == 0 && d_is_positive(new_dentry)) {
 		isp = smk_of_inode(d_backing_inode(new_dentry));
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
-		rc = smk_curacc(isp, MAY_READWRITE, &ad);
+		rc = smk_curacc(isp, ns, MAY_READWRITE, &ad);
 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_READWRITE, rc);
 	}
 	return rc;
@@ -1000,6 +1042,7 @@ static int smack_inode_rename(struct inode *old_inode,
  */
 static int smack_inode_permission(struct inode *inode, int mask)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int no_block = mask & MAY_NOT_BLOCK;
 	int rc;
@@ -1016,7 +1059,7 @@ static int smack_inode_permission(struct inode *inode, int mask)
 		return -ECHILD;
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 	smk_ad_setfield_u_fs_inode(&ad, inode);
-	rc = smk_curacc(smk_of_inode(inode), mask, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, mask, &ad);
 	rc = smk_bu_inode(inode, mask, rc);
 	return rc;
 }
@@ -1030,6 +1073,7 @@ static int smack_inode_permission(struct inode *inode, int mask)
  */
 static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -1041,7 +1085,8 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), ns,
+			MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	return rc;
 }
@@ -1055,13 +1100,14 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
  */
 static int smack_inode_getattr(const struct path *path)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	struct inode *inode = d_backing_inode(path->dentry);
 	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, *path);
-	rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, MAY_READ, &ad);
 	rc = smk_bu_inode(inode, MAY_READ, rc);
 	return rc;
 }
@@ -1083,6 +1129,9 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 {
 	struct smk_audit_info ad;
 	struct smack_known *skp;
+	struct smack_known *sbj = smk_of_current();
+	struct smack_known *obj = smk_of_inode(d_backing_inode(dentry));
+	struct user_namespace *ns = ns_of_current();
 	int check_priv = 0;
 	int check_import = 0;
 	int check_star = 0;
@@ -1109,11 +1158,12 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	} else
 		rc = cap_inode_setxattr(dentry, name, value, size, flags);
 
-	if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
+	if (check_priv && !(smk_labels_valid(sbj, obj, ns) &&
+			    smack_ns_privileged(ns, CAP_MAC_ADMIN)))
 		rc = -EPERM;
 
 	if (rc == 0 && check_import) {
-		skp = size ? smk_get_label(value, size, true) : NULL;
+		skp = size ? smk_get_label(value, size, true, ns) : NULL;
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else if (skp == NULL || (check_star &&
@@ -1125,7 +1175,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
 	if (rc == 0) {
-		rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+		rc = smk_curacc(obj, ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	}
 
@@ -1149,6 +1199,7 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 	struct smack_known *skp;
 	struct smack_known **skpp = NULL;
 	struct inode_smack *isp = d_backing_inode(dentry)->i_security;
+	struct user_namespace *ns = ns_of_current();
 
 	if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
@@ -1163,12 +1214,24 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 		skpp = &isp->smk_mmap;
 
 	if (skpp) {
-		skp = smk_get_label(value, size, true);
+		skp = smk_get_label(value, size, true, ns);
 
 		if (!IS_ERR(skp))
 			*skpp = skp;
 		else
 			*skpp = &smack_known_invalid;
+
+		/*
+		 * The label we get above might be a different than the one
+		 * kernel has already set before calling this function.
+		 * Be consistent and set the final value in the filesystem.
+		 * The cases for this are errors and labels being used
+		 * in a namespace where we want to store an unmapped
+		 * value in the filesystem.
+		 */
+		dentry->d_inode->i_op->setxattr(dentry, name,
+						(*skpp)->smk_known,
+						size, flags);
 	}
 }
 
@@ -1181,13 +1244,15 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
  */
 static int smack_inode_getxattr(struct dentry *dentry, const char *name)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_READ, &ad);
+	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), ns,
+			MAY_READ, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_READ, rc);
 	return rc;
 }
@@ -1204,6 +1269,9 @@ static int smack_inode_getxattr(struct dentry *dentry, const char *name)
 static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 {
 	struct inode_smack *isp;
+	struct smack_known *sbj = smk_of_current();
+	struct smack_known *obj = smk_of_inode(d_backing_inode(dentry));
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc = 0;
 
@@ -1213,7 +1281,8 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
 	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
 	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
-		if (!smack_privileged(CAP_MAC_ADMIN))
+		if (!smk_labels_valid(sbj, obj, ns) ||
+		    !smack_ns_privileged(ns, CAP_MAC_ADMIN))
 			rc = -EPERM;
 	} else
 		rc = cap_inode_removexattr(dentry, name);
@@ -1224,7 +1293,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+	rc = smk_curacc(obj, ns, MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	if (rc != 0)
 		return rc;
@@ -1264,13 +1333,18 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	struct super_block *sbp;
 	struct inode *ip = (struct inode *)inode;
 	struct smack_known *isp = NULL;
+	struct user_namespace *ns = ns_of_current();
 	int rc = 0;
 
 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0)
 		isp = smk_of_inode(inode);
+	else if (strcmp(name, XATTR_SMACK_EXEC) == 0)
+		isp = smk_of_exec(inode);
+	else if (strcmp(name, XATTR_SMACK_MMAP) == 0)
+		isp = smk_of_mmap(inode);
 
 	if (isp) {
-		*buffer = smk_find_label_name(isp);
+		*buffer = smk_find_label_name(isp, ns);
 		if (*buffer == NULL)
 			*buffer = smack_known_huh.smk_known;
 		return strlen(*buffer);
@@ -1297,7 +1371,7 @@ static int smack_inode_getsecurity(const struct inode *inode,
 		return -EOPNOTSUPP;
 
 	if (rc == 0) {
-		*buffer = smk_find_label_name(isp);
+		*buffer = smk_find_label_name(isp, ns);
 		if (*buffer == NULL)
 			*buffer = smack_known_huh.smk_known;
 		rc = strlen(*buffer);
@@ -1408,18 +1482,19 @@ static int smack_file_ioctl(struct file *file, unsigned int cmd,
 {
 	int rc = 0;
 	struct smk_audit_info ad;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
 
 	if (_IOC_DIR(cmd) & _IOC_WRITE) {
-		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_WRITE, &ad);
 		rc = smk_bu_file(file, MAY_WRITE, rc);
 	}
 
 	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
-		rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_READ, &ad);
 		rc = smk_bu_file(file, MAY_READ, rc);
 	}
 
@@ -1437,11 +1512,12 @@ static int smack_file_lock(struct file *file, unsigned int cmd)
 {
 	struct smk_audit_info ad;
 	int rc;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
-	rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, MAY_LOCK, &ad);
 	rc = smk_bu_file(file, MAY_LOCK, rc);
 	return rc;
 }
@@ -1463,6 +1539,7 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
 {
 	struct smk_audit_info ad;
 	int rc = 0;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	switch (cmd) {
@@ -1472,14 +1549,14 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
 	case F_SETLKW:
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
-		rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_LOCK, &ad);
 		rc = smk_bu_file(file, MAY_LOCK, rc);
 		break;
 	case F_SETOWN:
 	case F_SETSIG:
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
-		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_WRITE, &ad);
 		rc = smk_bu_file(file, MAY_WRITE, rc);
 		break;
 	default:
@@ -1509,6 +1586,7 @@ static int smack_mmap_file(struct file *file,
 	struct task_smack *tsp;
 	struct smack_known *okp;
 	struct inode_smack *isp;
+	struct user_namespace *sns;
 	int may;
 	int mmay;
 	int tmay;
@@ -1519,12 +1597,16 @@ static int smack_mmap_file(struct file *file,
 
 	tsp = current_security();
 	skp = smk_of_task(tsp);
+	sns = ns_of_current();
 	isp = file_inode(file)->i_security;
 	mkp = isp->smk_mmap;
 
 	if (mkp == NULL)
 		return 0;
 
+	if (!smk_labels_valid(skp, mkp, sns))
+		return -EACCES;
+
 	rc = 0;
 
 	rcu_read_lock();
@@ -1540,6 +1622,7 @@ static int smack_mmap_file(struct file *file,
 		 */
 		if (mkp->smk_known == okp->smk_known)
 			continue;
+
 		/*
 		 * If there is a matching local rule take
 		 * that into account as well.
@@ -1619,8 +1702,10 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 				     struct fown_struct *fown, int signum)
 {
 	struct smack_known *skp;
-	struct smack_known *tkp = smk_of_task(tsk->cred->security);
+	struct smack_known *tkp;
 	struct file *file;
+	struct user_namespace *sns;
+	struct user_namespace *tns;
 	int rc;
 	struct smk_audit_info ad;
 
@@ -1628,12 +1713,17 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 	 * struct fown_struct is never outside the context of a struct file
 	 */
 	file = container_of(fown, struct file, f_owner);
+	skp = file->f_security;
+	sns = file->f_cred->user_ns;
+
+	tkp = smk_of_task_struct(tsk);
+	tns = ns_of_task_struct(tsk);
 
 	/* we don't log here as rc can be overriden */
-	skp = file->f_security;
-	rc = smk_access(skp, tkp, MAY_WRITE, NULL);
+	rc = smk_access(skp, tkp, sns, MAY_WRITE, NULL);
 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc);
-	if (rc != 0 && smack_has_privilege(tsk, CAP_MAC_OVERRIDE))
+	if (rc != 0 && smk_labels_valid(skp, tkp, sns)
+	    && smack_has_ns_privilege(tsk, tns, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
@@ -1653,6 +1743,7 @@ static int smack_file_receive(struct file *file)
 	int rc;
 	int may = 0;
 	struct smk_audit_info ad;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	if (unlikely(IS_PRIVATE(inode)))
@@ -1668,7 +1759,7 @@ static int smack_file_receive(struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		may |= MAY_WRITE;
 
-	rc = smk_curacc(smk_of_inode(inode), may, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, may, &ad);
 	rc = smk_bu_file(file, may, rc);
 	return rc;
 }
@@ -1688,16 +1779,19 @@ static int smack_file_receive(struct file *file)
 static int smack_file_open(struct file *file, const struct cred *cred)
 {
 	struct task_smack *tsp = cred->security;
+	struct user_namespace *ns = cred->user_ns;
 	struct inode *inode = file_inode(file);
+	struct inode_smack *isp = file_inode(file)->i_security;
 	struct smk_audit_info ad;
 	int rc;
 
-	if (smack_privileged(CAP_MAC_OVERRIDE))
+	if (smk_labels_valid(tsp->smk_task, isp->smk_inode, ns) &&
+	    smack_ns_privileged(ns, CAP_MAC_OVERRIDE))
 		return 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
-	rc = smk_access(tsp->smk_task, smk_of_inode(inode), MAY_READ, &ad);
+	rc = smk_access(tsp->smk_task, smk_of_inode(inode), ns, MAY_READ, &ad);
 	rc = smk_bu_credfile(cred, file, MAY_READ, rc);
 
 	return rc;
@@ -1852,12 +1946,13 @@ static int smk_curacc_on_task(struct task_struct *p, int access,
 				const char *caller)
 {
 	struct smk_audit_info ad;
-	struct smack_known *skp = smk_of_task_struct(p);
+	struct smack_known *tkp = smk_of_task_struct(p);
+	struct user_namespace *tns = ns_of_task_struct(p);
 	int rc;
 
 	smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, p);
-	rc = smk_curacc(skp, access, &ad);
+	rc = smk_curacc(tkp, tns, access, &ad);
 	rc = smk_bu_task(p, access, rc);
 	return rc;
 }
@@ -1998,6 +2093,7 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	struct smk_audit_info ad;
 	struct smack_known *skp;
 	struct smack_known *tkp = smk_of_task_struct(p);
+	struct user_namespace *tns = ns_of_task_struct(p);
 	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
@@ -2007,7 +2103,7 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	 * can write the receiver.
 	 */
 	if (secid == 0) {
-		rc = smk_curacc(tkp, MAY_WRITE, &ad);
+		rc = smk_curacc(tkp, tns, MAY_WRITE, &ad);
 		rc = smk_bu_task(p, MAY_WRITE, rc);
 		return rc;
 	}
@@ -2017,8 +2113,10 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	 * we can't take privilege into account.
 	 */
 	skp = smack_from_secid(secid);
-	rc = smk_access(skp, tkp, MAY_WRITE, &ad);
+
+	rc = smk_access(skp, tkp, tns, MAY_WRITE, &ad);
 	rc = smk_bu_note("USB signal", skp, tkp, MAY_WRITE, rc);
+
 	return rc;
 }
 
@@ -2073,6 +2171,7 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 {
 	struct smack_known *skp = smk_of_current();
+	struct user_namespace *ns = ns_of_current();
 	struct socket_smack *ssp;
 
 	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
@@ -2082,6 +2181,7 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 	ssp->smk_in = skp;
 	ssp->smk_out = skp;
 	ssp->smk_packet = NULL;
+	ssp->smk_ns = get_user_ns(ns);
 
 	sk->sk_security = ssp;
 
@@ -2096,7 +2196,11 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
  */
 static void smack_sk_free_security(struct sock *sk)
 {
+	struct socket_smack *ssp = sk->sk_security;
+
+	put_user_ns(ssp->smk_ns);
 	kfree(sk->sk_security);
+	sk->sk_security = NULL;
 }
 
 /**
@@ -2191,6 +2295,7 @@ static int smack_netlabel(struct sock *sk, int labeled)
 static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
 {
 	struct smack_known *skp;
+	struct user_namespace *sns;
 	int rc;
 	int sk_lbl;
 	struct smack_known *hkp;
@@ -2210,7 +2315,8 @@ static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
 #endif
 		sk_lbl = SMACK_UNLABELED_SOCKET;
 		skp = ssp->smk_out;
-		rc = smk_access(skp, hkp, MAY_WRITE, &ad);
+		sns = ssp->smk_ns;
+		rc = smk_access(skp, hkp, sns, MAY_WRITE, &ad);
 		rc = smk_bu_note("IPv4 host check", skp, hkp, MAY_WRITE, rc);
 	} else {
 		sk_lbl = SMACK_CIPSO_SOCKET;
@@ -2312,6 +2418,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 	struct smk_port_label *spp;
 	struct socket_smack *ssp = sk->sk_security;
 	struct smack_known *skp;
+	struct user_namespace *sns = ssp->smk_ns;
 	unsigned short port = 0;
 	struct smack_known *object;
 	struct smk_audit_info ad;
@@ -2369,7 +2476,7 @@ auditout:
 	else
 		ad.a.u.net->v6info.daddr = address->sin6_addr;
 #endif
-	rc = smk_access(skp, object, MAY_WRITE, &ad);
+	rc = smk_access(skp, object, sns, MAY_WRITE, &ad);
 	rc = smk_bu_note("IPv6 port check", skp, object, MAY_WRITE, rc);
 	return rc;
 }
@@ -2394,12 +2501,13 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	struct inode_smack *nsp = inode->i_security;
 	struct socket_smack *ssp;
 	struct socket *sock;
+	struct user_namespace *ns = ns_of_current();
 	int rc = 0;
 
 	if (value == NULL || size > SMK_LONGLABEL || size == 0)
 		return -EINVAL;
 
-	skp = smk_import_entry(value, size);
+	skp = smk_get_label(value, size, true, ns);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
 
@@ -2584,14 +2692,14 @@ static void smack_msg_msg_free_security(struct msg_msg *msg)
 }
 
 /**
- * smack_of_shm - the smack pointer for the shm
+ * security_of_shm - the smack pointer for the shm
  * @shp: the object
  *
- * Returns a pointer to the smack value
+ * Returns a pointer to the security_smack struct
  */
-static struct smack_known *smack_of_shm(struct shmid_kernel *shp)
+static struct ipc_smack *security_of_shm(struct shmid_kernel *shp)
 {
-	return (struct smack_known *)shp->shm_perm.security;
+	return (struct ipc_smack *)shp->shm_perm.security;
 }
 
 /**
@@ -2603,9 +2711,16 @@ static struct smack_known *smack_of_shm(struct shmid_kernel *shp)
 static int smack_shm_alloc_security(struct shmid_kernel *shp)
 {
 	struct kern_ipc_perm *isp = &shp->shm_perm;
-	struct smack_known *skp = smk_of_current();
+	struct ipc_smack *ssp;
 
-	isp->security = skp;
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
+
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
+
+	isp->security = ssp;
 	return 0;
 }
 
@@ -2618,7 +2733,10 @@ static int smack_shm_alloc_security(struct shmid_kernel *shp)
 static void smack_shm_free_security(struct shmid_kernel *shp)
 {
 	struct kern_ipc_perm *isp = &shp->shm_perm;
+	struct ipc_smack *ssp = isp->security;
 
+	put_user_ns(ssp->smk_ns);
+	kfree(isp->security);
 	isp->security = NULL;
 }
 
@@ -2631,7 +2749,7 @@ static void smack_shm_free_security(struct shmid_kernel *shp)
  */
 static int smk_curacc_shm(struct shmid_kernel *shp, int access)
 {
-	struct smack_known *ssp = smack_of_shm(shp);
+	struct ipc_smack *ssp = security_of_shm(shp);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -2639,8 +2757,8 @@ static int smk_curacc_shm(struct shmid_kernel *shp, int access)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = shp->shm_perm.id;
 #endif
-	rc = smk_curacc(ssp, access, &ad);
-	rc = smk_bu_current("shm", ssp, access, rc);
+	rc = smk_curacc(ssp->smk_known, ssp->smk_ns, access, &ad);
+	rc = smk_bu_current("shm", ssp->smk_known, access, rc);
 	return rc;
 }
 
@@ -2711,14 +2829,14 @@ static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
 }
 
 /**
- * smack_of_sem - the smack pointer for the sem
+ * security_of_sem - the smack pointer for the sem
  * @sma: the object
  *
- * Returns a pointer to the smack value
+ * Returns a pointer to the ipc_smack struct
  */
-static struct smack_known *smack_of_sem(struct sem_array *sma)
+static struct ipc_smack *security_of_sem(struct sem_array *sma)
 {
-	return (struct smack_known *)sma->sem_perm.security;
+	return (struct ipc_smack *)sma->sem_perm.security;
 }
 
 /**
@@ -2730,9 +2848,16 @@ static struct smack_known *smack_of_sem(struct sem_array *sma)
 static int smack_sem_alloc_security(struct sem_array *sma)
 {
 	struct kern_ipc_perm *isp = &sma->sem_perm;
-	struct smack_known *skp = smk_of_current();
+	struct ipc_smack *ssp;
 
-	isp->security = skp;
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
+
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
+
+	isp->security = ssp;
 	return 0;
 }
 
@@ -2745,7 +2870,10 @@ static int smack_sem_alloc_security(struct sem_array *sma)
 static void smack_sem_free_security(struct sem_array *sma)
 {
 	struct kern_ipc_perm *isp = &sma->sem_perm;
+	struct ipc_smack *ssp = isp->security;
 
+	put_user_ns(ssp->smk_ns);
+	kfree(isp->security);
 	isp->security = NULL;
 }
 
@@ -2758,7 +2886,7 @@ static void smack_sem_free_security(struct sem_array *sma)
  */
 static int smk_curacc_sem(struct sem_array *sma, int access)
 {
-	struct smack_known *ssp = smack_of_sem(sma);
+	struct ipc_smack *ssp = security_of_sem(sma);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -2766,8 +2894,8 @@ static int smk_curacc_sem(struct sem_array *sma, int access)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = sma->sem_perm.id;
 #endif
-	rc = smk_curacc(ssp, access, &ad);
-	rc = smk_bu_current("sem", ssp, access, rc);
+	rc = smk_curacc(ssp->smk_known, ssp->smk_ns, access, &ad);
+	rc = smk_bu_current("sem", ssp->smk_known, access, rc);
 	return rc;
 }
 
@@ -2852,9 +2980,16 @@ static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
 static int smack_msg_queue_alloc_security(struct msg_queue *msq)
 {
 	struct kern_ipc_perm *kisp = &msq->q_perm;
-	struct smack_known *skp = smk_of_current();
+	struct ipc_smack *ssp;
+
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
+
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
 
-	kisp->security = skp;
+	kisp->security = ssp;
 	return 0;
 }
 
@@ -2867,19 +3002,22 @@ static int smack_msg_queue_alloc_security(struct msg_queue *msq)
 static void smack_msg_queue_free_security(struct msg_queue *msq)
 {
 	struct kern_ipc_perm *kisp = &msq->q_perm;
+	struct ipc_smack *ssp = kisp->security;
 
+	put_user_ns(ssp->smk_ns);
+	kfree(kisp->security);
 	kisp->security = NULL;
 }
 
 /**
- * smack_of_msq - the smack pointer for the msq
+ * security_of_msq - the smack pointer for the msq
  * @msq: the object
  *
- * Returns a pointer to the smack label entry
+ * Returns a pointer to the ipc_smack struct
  */
-static struct smack_known *smack_of_msq(struct msg_queue *msq)
+static struct ipc_smack *security_of_msq(struct msg_queue *msq)
 {
-	return (struct smack_known *)msq->q_perm.security;
+	return (struct ipc_smack *)msq->q_perm.security;
 }
 
 /**
@@ -2891,7 +3029,7 @@ static struct smack_known *smack_of_msq(struct msg_queue *msq)
  */
 static int smk_curacc_msq(struct msg_queue *msq, int access)
 {
-	struct smack_known *msp = smack_of_msq(msq);
+	struct ipc_smack *msp = security_of_msq(msq);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -2899,8 +3037,8 @@ static int smk_curacc_msq(struct msg_queue *msq, int access)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = msq->q_perm.id;
 #endif
-	rc = smk_curacc(msp, access, &ad);
-	rc = smk_bu_current("msq", msp, access, rc);
+	rc = smk_curacc(msp->smk_known, msp->smk_ns, access, &ad);
+	rc = smk_bu_current("msq", msp->smk_known, access, rc);
 	return rc;
 }
 
@@ -2994,7 +3132,7 @@ static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
  */
 static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 {
-	struct smack_known *iskp = ipp->security;
+	struct ipc_smack *isp = ipp->security;
 	int may = smack_flags_to_may(flag);
 	struct smk_audit_info ad;
 	int rc;
@@ -3003,8 +3141,8 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = ipp->id;
 #endif
-	rc = smk_curacc(iskp, may, &ad);
-	rc = smk_bu_current("svipc", iskp, may, rc);
+	rc = smk_curacc(isp->smk_known, isp->smk_ns, may, &ad);
+	rc = smk_bu_current("svipc", isp->smk_known, may, rc);
 	return rc;
 }
 
@@ -3015,9 +3153,9 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
  */
 static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
 {
-	struct smack_known *iskp = ipp->security;
+	struct ipc_smack *iskp = ipp->security;
 
-	*secid = iskp->smk_secid;
+	*secid = iskp->smk_known->smk_secid;
 }
 
 /**
@@ -3251,13 +3389,14 @@ unlockandout:
 static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 {
 	struct smack_known *skp = smk_of_task_struct(p);
+	struct user_namespace *ns = ns_of_current();
 	char *cp;
 	int slen;
 
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	cp = smk_find_label_name(skp);
+	cp = smk_find_label_name(skp, ns);
 	if (cp == NULL)
 		cp = smack_known_huh.smk_known;
 	cp = kstrdup(cp, GFP_KERNEL);
@@ -3287,6 +3426,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	struct task_smack *tsp;
 	struct cred *new;
 	struct smack_known *skp;
+	struct user_namespace *ns;
 
 	/*
 	 * Changing another process' Smack value is too dangerous
@@ -3295,7 +3435,9 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	if (p != current)
 		return -EPERM;
 
-	if (!smack_privileged(CAP_MAC_ADMIN))
+	ns = ns_of_current();
+
+	if (!smack_ns_privileged(ns, CAP_MAC_ADMIN))
 		return -EPERM;
 
 	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
@@ -3304,7 +3446,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	skp = smk_get_label(value, size, true);
+	skp = smk_get_label(value, size, true, ns);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
 
@@ -3344,23 +3486,27 @@ static int smack_unix_stream_connect(struct sock *sock,
 	struct smack_known *okp_out = osp->smk_out;
 	struct smack_known *skp_in = ssp->smk_in;
 	struct smack_known *okp_in = osp->smk_in;
+	struct user_namespace *sns = ssp->smk_ns;
+	struct user_namespace *ons = osp->smk_ns;
 	struct smk_audit_info ad;
 	int rc = 0;
 #ifdef CONFIG_AUDIT
 	struct lsm_network_audit net;
 #endif
 
-	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
+	if (!smack_ns_privileged(ons, CAP_MAC_OVERRIDE) ||
+	    !smk_labels_valid(skp_out, okp_in, sns) ||
+	    !smk_labels_valid(okp_out, skp_in, ons)) {
 #ifdef CONFIG_AUDIT
 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
 		smk_ad_setfield_u_net_sk(&ad, other);
 #endif
-		rc = smk_access(skp_out, okp_in, MAY_WRITE, &ad);
+		rc = smk_access(skp_out, okp_in, sns, MAY_WRITE, &ad);
 		rc = smk_bu_note("UDS connect", skp_out, okp_in, MAY_WRITE, rc);
 		if (rc == 0) {
-			rc = smk_access(okp_out, skp_in, MAY_WRITE, &ad);
+			rc = smk_access(okp_out, skp_in, ons, MAY_WRITE, &ad);
 			rc = smk_bu_note("UDS connect", okp_out, skp_in,
-						MAY_WRITE, rc);
+					 MAY_WRITE, rc);
 		}
 	}
 
@@ -3387,6 +3533,8 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 {
 	struct socket_smack *ssp = sock->sk->sk_security;
 	struct socket_smack *osp = other->sk->sk_security;
+	struct user_namespace *sns = ssp->smk_ns;
+	struct user_namespace *ons = osp->smk_ns;
 	struct smk_audit_info ad;
 	int rc;
 
@@ -3397,10 +3545,11 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 	smk_ad_setfield_u_net_sk(&ad, other->sk);
 #endif
 
-	if (smack_privileged(CAP_MAC_OVERRIDE))
+	if (smk_labels_valid(ssp->smk_out, osp->smk_in, sns) &&
+	    smack_ns_privileged(ons, CAP_MAC_OVERRIDE))
 		return 0;
 
-	rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
+	rc = smk_access(ssp->smk_out, osp->smk_in, sns, MAY_WRITE, &ad);
 	rc = smk_bu_note("UDS send", ssp->smk_out, osp->smk_in, MAY_WRITE, rc);
 	return rc;
 }
@@ -3640,7 +3789,7 @@ access_check:
 		 * This is the simplist possible security model
 		 * for networking.
 		 */
-		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+		rc = smk_access(skp, ssp->smk_in, ssp->smk_ns, MAY_WRITE, &ad);
 		rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
 					MAY_WRITE, rc);
 		if (rc != 0)
@@ -3662,7 +3811,7 @@ access_check:
 		ad.a.u.net->netif = skb->skb_iif;
 		ipv6_skb_to_auditdata(skb, &ad.a, NULL);
 #endif /* CONFIG_AUDIT */
-		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+		rc = smk_access(skp, ssp->smk_in, ssp->smk_ns, MAY_WRITE, &ad);
 		rc = smk_bu_note("IPv6 delivery", skp, ssp->smk_in,
 					MAY_WRITE, rc);
 #else /* CONFIG_SECURITY_SMACK_NETFILTER */
@@ -3875,7 +4024,7 @@ access_check:
 	 * Receiving a packet requires that the other end be able to write
 	 * here. Read access is not required.
 	 */
-	rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+	rc = smk_access(skp, ssp->smk_in, ssp->smk_ns, MAY_WRITE, &ad);
 	rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in, MAY_WRITE, rc);
 	if (rc != 0)
 		return rc;
@@ -3979,6 +4128,7 @@ static int smack_key_permission(key_ref_t key_ref,
 	struct key *keyp;
 	struct smk_audit_info ad;
 	struct smack_known *tkp = smk_of_task(cred->security);
+	struct user_namespace *tns = cred->user_ns;
 	int request = 0;
 	int rc;
 
@@ -4005,7 +4155,7 @@ static int smack_key_permission(key_ref_t key_ref,
 		request = MAY_READ;
 	if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
 		request = MAY_WRITE;
-	rc = smk_access(tkp, keyp->security, request, &ad);
+	rc = smk_access(tkp, keyp->security, tns, request, &ad);
 	rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
 	return rc;
 }
@@ -4022,6 +4172,7 @@ static int smack_key_permission(key_ref_t key_ref,
 static int smack_key_getsecurity(struct key *key, char **_buffer)
 {
 	struct smack_known *skp = key->security;
+	struct user_namespace *ns = ns_of_current();
 	size_t length;
 	char *copy;
 
@@ -4030,7 +4181,7 @@ static int smack_key_getsecurity(struct key *key, char **_buffer)
 		return 0;
 	}
 
-	copy = smk_find_label_name(skp);
+	copy = smk_find_label_name(skp, ns);
 	if (copy == NULL)
 		copy = smack_known_huh.smk_known;
 	copy = kstrdup(copy, GFP_KERNEL);
@@ -4208,6 +4359,11 @@ static inline void smack_userns_free(struct user_namespace *ns)
 static inline int smack_userns_setns(struct nsproxy *nsproxy,
 				     struct user_namespace *ns)
 {
+	struct smack_known *skp = smk_of_current();
+
+	if (smk_find_mapped(skp, ns) == NULL)
+		return -EACCES;
+
 	return 0;
 }
 
diff --git a/security/smack/smack_ns.c b/security/smack/smack_ns.c
index 141a836..819c490 100644
--- a/security/smack/smack_ns.c
+++ b/security/smack/smack_ns.c
@@ -206,6 +206,45 @@ unlockout:
 	return sknp;
 }
 
+/**
+ * smk_labels_valid - A helper to check whether labels are valid/mapped
+ *                    in the namespace and can be used there
+ * @sbj: a subject label to be checked
+ * @obj: an object label to be checked
+ * @ns: user namespace to check against (usually subject's)
+ *
+ * Returns true if both valid/mapped, false otherwise.
+ * This helper is mostly used while checking capabilities.
+ * The access functions check the validity of labels by themselves.
+ */
+bool smk_labels_valid(struct smack_known *sbj, struct smack_known *obj,
+		      struct user_namespace *ns)
+{
+	struct user_namespace *user_ns;
+
+	/*
+	 * labels are always valid if there is no map
+	 * (init_user_ns or unmapped descendants)
+	 */
+	user_ns = smk_find_mapped_ns(ns);
+	if (user_ns == NULL)
+		return true;
+
+	/*
+	 * If we have a map though, both labels need to be mapped.
+	 */
+	if (__smk_find_mapped(sbj, user_ns) == NULL)
+		return false;
+	if (__smk_find_mapped(obj, user_ns) == NULL)
+		return false;
+
+	return true;
+}
+
+/*
+ * proc mapping operations
+ */
+
 static void *proc_smack_map_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	struct smack_known *skp;
@@ -253,7 +292,7 @@ static int proc_smack_map_seq_show(struct seq_file *seq, void *v)
 	 * to show identity in this syntax without printing all the labels.
 	 */
 	if (smk_find_mapped_ns(ns) == NULL) {
-		seq_puts("This namespace is not mapped.\n");
+		seq_puts(seq, "This namespace is not mapped.\n");
 	} else {
 		sknp = smk_find_mapped(skp, ns);
 		if (sknp)
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 5ec1e8e..7196861 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -345,13 +345,15 @@ static int smk_fill_rule(const char *subject, const char *object,
 				struct smack_parsed_rule *rule, int import,
 				int len)
 {
-	rule->smk_subject = smk_get_label(subject, len, import);
+	struct user_namespace *ns = ns_of_current();
+
+	rule->smk_subject = smk_get_label(subject, len, import, ns);
 	if (IS_ERR(rule->smk_subject))
 		return PTR_ERR(rule->smk_subject);
 	if (rule->smk_subject == NULL)
 		return -ENOENT;
 
-	rule->smk_object = smk_get_label(object, len, import);
+	rule->smk_object = smk_get_label(object, len, import, ns);
 	if (IS_ERR(rule->smk_object))
 		return PTR_ERR(rule->smk_object);
 	if (rule->smk_object == NULL)
@@ -586,6 +588,7 @@ static void smk_seq_stop(struct seq_file *s, void *v)
 
 static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 {
+	struct user_namespace *ns = ns_of_current();
 	char *sbj;
 	char *obj;
 
@@ -594,6 +597,7 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	 * interface file (/smack/load or /smack/load2)
 	 * because you should expect to be able to write
 	 * anything you read back.
+	 * Show only fully mapped rules in a namespace (both labels mapped).
 	 */
 	if (strlen(srp->smk_subject->smk_known) >= max ||
 	    strlen(srp->smk_object->smk_known) >= max)
@@ -602,8 +606,8 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	if (srp->smk_access == 0)
 		return;
 
-	sbj = smk_find_label_name(srp->smk_subject);
-	obj = smk_find_label_name(srp->smk_object);
+	sbj = smk_find_label_name(srp->smk_subject, ns);
+	obj = smk_find_label_name(srp->smk_object, ns);
 
 	if (sbj == NULL || obj == NULL)
 		return;
@@ -798,6 +802,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	struct smack_known *skp =
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
+	struct user_namespace *ns = ns_of_current();
 	char sep = '/';
 	char *cp;
 	int i;
@@ -813,7 +818,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	if (strlen(skp->smk_known) >= SMK_LABELLEN)
 		return 0;
 
-	cp = smk_find_label_name(skp);
+	cp = smk_find_label_name(skp, ns);
 	if (cp == NULL)
 		return 0;
 
@@ -866,6 +871,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 {
 	struct smack_known *skp;
 	struct netlbl_lsm_secattr ncats;
+	struct user_namespace *ns = ns_of_current();
 	char mapcatset[SMK_CIPSOLEN];
 	int maplevel;
 	unsigned int cat;
@@ -906,7 +912,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 	 */
 	mutex_lock(&smack_cipso_lock);
 
-	skp = smk_get_label(rule, 0, true);
+	skp = smk_get_label(rule, 0, true, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -994,11 +1000,12 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
 	struct smack_known *skp =
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
+	struct user_namespace *ns = ns_of_current();
 	char sep = '/';
 	char *cp;
 	int i;
 
-	cp = smk_find_label_name(skp);
+	cp = smk_find_label_name(skp, ns);
 	if (cp == NULL)
 		return 0;
 
@@ -1085,7 +1092,8 @@ static int netlbladdr_seq_show(struct seq_file *s, void *v)
 	unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
 	int maskn;
 	u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
-	char *label = smk_find_label_name(skp->smk_label);
+	struct user_namespace *ns = ns_of_current();
+	char *label = smk_find_label_name(skp->smk_label, ns);
 
 	if (label == NULL)
 		return 0;
@@ -1182,6 +1190,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	int rc;
 	struct netlbl_audit audit_info;
 	struct in_addr mask;
+	struct user_namespace *ns = ns_of_current();
 	unsigned int m;
 	int found;
 	u32 mask_bits = (1<<31);
@@ -1239,7 +1248,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	 * If smack begins with '-', it is an option, don't import it
 	 */
 	if (smack[0] != '-') {
-		skp = smk_get_label(smack, 0, true);
+		skp = smk_get_label(smack, 0, true, ns);
 		if (IS_ERR(skp)) {
 			rc = PTR_ERR(skp);
 			goto free_out;
@@ -1567,6 +1576,7 @@ static const struct file_operations smk_mapped_ops = {
 static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
+	struct user_namespace *ns = ns_of_current();
 	ssize_t rc;
 	char *cp;
 	int asize;
@@ -1579,7 +1589,7 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 	 */
 	mutex_lock(&smack_ambient_lock);
 
-	cp = smk_find_label_name(smack_net_ambient);
+	cp = smk_find_label_name(smack_net_ambient, ns);
 	if (cp == NULL)
 		cp = smack_known_huh.smk_known;
 
@@ -1608,6 +1618,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 				 size_t count, loff_t *ppos)
 {
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	char *oldambient;
 	char *data;
 	int rc = count;
@@ -1624,7 +1635,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 		goto out;
 	}
 
-	skp = smk_get_label(data, count, true);
+	skp = smk_get_label(data, count, true, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -1664,12 +1675,13 @@ static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
 	char *smack = "";
 	ssize_t rc = -EINVAL;
 	int asize;
+	struct user_namespace *ns = ns_of_current();
 
 	if (*ppos != 0)
 		return 0;
 
 	if (smack_onlycap != NULL) {
-		smack = smk_find_label_name(smack_onlycap);
+		smack = smk_find_label_name(smack_onlycap, ns);
 		if (smack == NULL)
 			smack = smack_known_huh.smk_known;
 	}
@@ -1696,6 +1708,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 {
 	char *data;
 	struct smack_known *skp = smk_of_task(current->cred->security);
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -1727,7 +1740,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_get_label(data, count, true);
+	skp = smk_get_label(data, count, true, ns);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -1764,12 +1777,13 @@ static ssize_t smk_read_unconfined(struct file *filp, char __user *buf,
 	char *smack = "";
 	ssize_t rc = -EINVAL;
 	int asize;
+	struct user_namespace *ns = ns_of_current();
 
 	if (*ppos != 0)
 		return 0;
 
 	if (smack_unconfined != NULL) {
-		smack = smk_find_label_name(smack_unconfined);
+		smack = smk_find_label_name(smack_unconfined, ns);
 		if (smack == NULL)
 			smack = smack_known_huh.smk_known;
 	}
@@ -1796,6 +1810,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 {
 	char *data;
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -1819,7 +1834,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_get_label(data, count, true);
+	skp = smk_get_label(data, count, true, ns);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -1991,6 +2006,7 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos, int format)
 {
 	struct smack_parsed_rule rule;
+	struct user_namespace *ns = ns_of_current();
 	char *data;
 	int res;
 
@@ -2010,7 +2026,7 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf,
 	}
 
 	if (res >= 0)
-		res = smk_access(rule.smk_subject, rule.smk_object,
+		res = smk_access(rule.smk_subject, rule.smk_object, ns,
 				 rule.smk_access1, NULL);
 	else if (res != -ENOENT)
 		return res;
@@ -2220,6 +2236,7 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 	struct smack_rule *sp;
 	struct list_head *rule_list;
 	struct mutex *rule_lock;
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (*ppos != 0)
@@ -2240,7 +2257,7 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 		goto free_out;
 	}
 
-	skp = smk_get_label(data, count, false);
+	skp = smk_get_label(data, count, false, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto free_out;
@@ -2322,6 +2339,7 @@ static const struct file_operations smk_change_rule_ops = {
 static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
+	struct user_namespace *ns = ns_of_current();
 	ssize_t rc = -EINVAL;
 	char *cp;
 	int asize;
@@ -2332,7 +2350,7 @@ static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 	if (smack_syslog_label == NULL)
 		cp = smack_known_star.smk_known;
 	else {
-		cp = smk_find_label_name(smack_syslog_label);
+		cp = smk_find_label_name(smack_syslog_label, ns);
 		if (cp == NULL)
 			cp = smack_known_huh.smk_known;
 	}
@@ -2359,6 +2377,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 {
 	char *data;
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -2371,7 +2390,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (copy_from_user(data, buf, count) != 0)
 		rc = -EFAULT;
 	else {
-		skp = smk_get_label(data, count, true);
+		skp = smk_get_label(data, count, true, ns);
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else
-- 
2.1.0

[PATCH 8/8] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

Adds Documentation/smack-namespace.txt.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 Documentation/security/00-INDEX            |   2 +
 Documentation/security/Smack-namespace.txt | 231 +++++++++++++++++++++++++++++
 MAINTAINERS                                |   1 +
 security/smack/Kconfig                     |   2 +
 4 files changed, 236 insertions(+)
 create mode 100644 Documentation/security/Smack-namespace.txt

diff --git a/Documentation/security/00-INDEX b/Documentation/security/00-INDEX
index 45c82fd..c03a220 100644
--- a/Documentation/security/00-INDEX
+++ b/Documentation/security/00-INDEX
@@ -6,6 +6,8 @@ SELinux.txt
 	- how to get started with the SELinux security enhancement.
 Smack.txt
 	- documentation on the Smack Linux Security Module.
+Smack-namespace.txt
+	- documentation on the Smack namespace implementation.
 Yama.txt
 	- documentation on the Yama Linux Security Module.
 apparmor.txt
diff --git a/Documentation/security/Smack-namespace.txt b/Documentation/security/Smack-namespace.txt
new file mode 100644
index 0000000..85197ff
--- /dev/null
+++ b/Documentation/security/Smack-namespace.txt
@@ -0,0 +1,231 @@
+
+                                      "Quis custodiet ipsos custodes?"
+                                                 - Satires of Juvenal
+
+
+--- What is a Smack namespace ---
+
+Smack namespace was developed to make it possible for Smack to work
+nicely with Linux containers where there is a full operating system
+with its own init inside the namespace. Such a system working with
+Smack expects to have at least partially working SMACK_MAC_ADMIN to be
+able to change labels of processes and files. This is required to be
+able to securely start applications under the control of Smack and
+manage their access rights.
+
+It was implemented using new LSM hooks added to the user namespace
+that were developed together with Smack namespace.
+
+
+--- Design ideas ---
+
+"Smack namespace" is rather "Smack labels namespace" as not the whole
+MAC is namespaced, only the labels. There is a great analogy between
+Smack labels namespace and the user namespace part that remaps UIDs.
+
+The idea is to create a map of labels for a namespace so the namespace
+is only allowed to use those labels. Smack rules are always the same
+as in the init namespace (limited only by what labels are mapped) and
+cannot be manipulated from the child namespace. The map is actually
+only for labels' names. The underlying structures for labels remain
+the same. The filesystem also stores the "unmapped" labels from the
+init namespace.
+
+Let's say we have those labels in the init namespace:
+label1
+label2
+label3
+
+and those rules:
+label1 label2 rwx
+label1 label3 rwx
+label2 label3 rwx
+
+We create a map for a namespace:
+label1 -> mapped1
+label2 -> mapped2
+
+This means that 'label3' is completely invisible in the namespace. As if
+it didn't exist. All the rules that include it are ignored.
+
+Effectively in the namespace we have only one rule:
+mapped1 mapped2 rwx
+
+Which in reality is:
+label1 label2 rwx
+
+All requests to access an object with a 'label3' will be denied. If it
+ever comes to a situation where 'label3' would have to be printed
+(e.g. reading an exec or mmap label from a file to which we have
+access) then huh sign '?' will be printed instead.
+
+All the operations in the namespace on the remaining labels will have
+to be performed using their mapped names. Things like changing own
+process's label, changing filesystem label. Labels will also be
+printed with their mapped names.
+
+You cannot import new labels in a namespace. Every operation that
+would do so in an init namespace will return an error in the child
+namespace. You cannot assign an unmapped or not existing label to an
+object. You can only operate on labels that have been explicitly
+mapped.
+
+
+--- Capabilities ---
+
+Enabling Smack related capabilities (CAP_MAC_ADMIN and
+CAP_MAC_OVERRIDE) is main goal of Smack namespace, so it can work
+properly in the container. And those capabilities do work to some
+extent. In several places where capabilities are checked compatibility
+with Smack namespace has been introduced. Capabilities are of course
+limited to operate only on mapped labels.
+
+CAP_MAC_OVERRIDE works fully, will allow you to ignore Smack access
+rules, but only between objects that have labels mapped. So in the
+example above having this CAP will allow e.g. label2 to write to
+label1, but will not allow any access to label3.
+
+With CAP_MAC_ADMIN the following operations has been allowed inside
+the namespace:
+- setting and removing xattr on files, including the security.* ones
+- setting process's own label (/proc/self/attr/current)
+- mounting in a privileged Smack mode, which means one can specify
+  additional mount options like: smackfsdef, smackfsfloor etc.
+
+Again this is also allowed only on the mapped labels. Labels on the
+filesystem will be stored in unmapped form so they are preserved
+through reboots.
+
+Such a namespace construct allows e.g. systemd (with Smack support)
+working in a container to assign labels properly to daemons and other
+processes.
+
+
+--- Usage ---
+
+Smack namespace is written using LSM hooks inside user namespace. That
+means it's connected to it.
+
+To create a new Smack namespace you need to unshare() user namespace
+as usual. If that is all you do though, than there is no difference to
+what is now. To activate the Smack namespace you need to fill the
+labels' map. It is in a file /proc/$PID/smack_map.
+
+By default the map is empty and Smack namespaces are inactive (labels
+are taken directly from a parent namespace). It also means that the
+Smack capabilities will be inactive. After you fill the map it starts
+to take effect in the namespace and Smack capabilities (only on mapped
+labels) start to work.
+
+Due to the way Smack works only CAP_MAC_ADMIN from the parent
+namespace (init_user_ns for now, see the "Current limitations" below)
+is allowed to fill the map. That means that an unprivileged user is
+still allowed to create the user namespace but it will not be able to
+fill the labels' map (activate Smack namespace). An administrator
+intervention is required.
+
+The attr_map write format is:
+unmapped_label mapped_label
+
+When reading the file it shows an active map for a namespace the
+process in question is in in the format:
+unmapped_label -> mapped_label
+
+If the smack_map file is empty it means the namespace is not mapped
+and Smack namespace is inactive (no mappings, MAC related capabilities
+behave as they did before, meaning they are active only in
+init_user_ns). For init_user_ns the map will always be empty.
+
+Writing to the map file is not disabled after the first write as it is
+in uid_map. For Smack we have no means to map ranges of labels, hence
+it can really be advantageous to be able to expand the map later
+on. But you can only add to the map. You cannot remove already mapped
+labels. You cannot change the already existing mappings. Also mappings
+has to be 1-1. All requests to create a map where either the unmapped
+or the mapped label already exists in the map will be denied.
+
+setns() with Smack namespace active has an additional check that the
+label of a process that is calling setns() has to be already mapped in
+the target Smack namespace for the call to succeed.
+
+
+--- Special labels ---
+
+Smack is using some special labels that have built-in rules. Things
+like floor '_', dash '^', star '*', etc. Those labels are not
+automatically mapped to the namespace. Moreover, you can choose to map
+a different label from the init namespace to behave e.g. like floor
+inside the namespace.
+
+Let's say we have no rules and those labels in the init namespace:
+_
+floor_to_be
+label
+
+Both 'label' and 'floor_to_be' can read objects with '_'. But they
+have no access rights to each other.
+
+Now let's create a map like this:
+_             ordinary_label
+floor_to_be   _
+label         mapped
+
+Right now label 'mapped' can read label '_' which means that
+effectively inside this namespace label 'label' has gained read access
+to the 'floor_to_be'. The label 'ordinary_label' is exactly it, an
+ordinary label that the built-in rules no longer apply to inside the
+namespace.
+
+To sum up, special labels in the namespace behave the same as in the
+init namespace. Not the original special labels though, but the ones
+we map to specials. This is the only case where a namespace can have
+access rights the init namespace does not have (like the 'label' to
+'floor_to_be' in the example above).
+
+Of course mappings like these are perfectly legal:
+_   _
+*   *
+^   ^
+
+
+--- Current limitations ---
+
+The Smack namespace is not hierarchical yet. It is currently not
+possible to fill a smack_map of a nested user namespace (you can still
+create nested user namespace, it will just inherit its parent's map
+and won't have active Smack capabilities). When hierarchy will be
+implemented the process creating another namespace will be allowed to
+map only labels that it has permission to itself (those that it has in
+its own map).
+
+Special files inside the virtual smackfs needs to be reviewed whether
+it's beneficial to have some of their functionality namespaced as well
+(e.g. onlycap, syslog. ambient, etc). This would increase
+CAP_MAC_ADMIN privileges inside the namespace.
+
+
+--- Error codes ---
+
+While working in the namespace patches the error codes has been made
+to propagate properly from a place they occurred. New error codes has
+also been introduced for Smack in the context of namespace usage. This
+is a complete summary of error codes used throughout the Smack now:
+
+ENOMEM      and other system errors that might come from low level
+            kernel functions like memory allocations
+EOPNOTSUPP  means the underlying system operation is not
+            supported (eg. getxattr)
+EINVAL      means invalid syntax (e.g. empty label or one starting
+            with '-')
+EEXIST      when creating map means that a label is already mapped
+EBADR       is used for wrong namespace usage:
+            - trying to import a label inside a namespace (like trying
+              to use an unmapped label that would otherwise be imported)
+            - trying to create a Smack label map in the init namespace
+ENOENT      when failed to find a label we expected to exist (will not
+            be propagated to user-space)
+EPERM       means no permission to operate on an object, e.g. due to
+            insufficient capabilities or simply because the object
+	    cannot be operated on in the current context
+EACCESS     when access has been denied due to Smack access checks
+            (including object being outside of a namespace)
diff --git a/MAINTAINERS b/MAINTAINERS
index 2e5bbc0..66ab25b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9059,6 +9059,7 @@ W:	http://schaufler-ca.com
 T:	git git://git.gitorious.org/smack-next/kernel.git
 S:	Maintained
 F:	Documentation/security/Smack.txt
+F:	Documentation/security/Smack-namespace.txt
 F:	security/smack/
 
 DRIVERS FOR ADAPTIVE VOLTAGE SCALING (AVS)
diff --git a/security/smack/Kconfig b/security/smack/Kconfig
index b19a7fb..a6e0f3f 100644
--- a/security/smack/Kconfig
+++ b/security/smack/Kconfig
@@ -49,4 +49,6 @@ config SECURITY_SMACK_NS
 	  This enables Smack namespace that makes it possible to map
 	  specific labels within user namespace (analogously to mapping
 	  UIDs) and to gain MAC capabilities over them.
+	  Documentation is availabile here:
+	  Documentation/security/Smack-namespace.txt
 	  If you are unsure how to answer this question, answer N.
-- 
2.1.0

[PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

Hello,

Some time ago I sent a Smack namespace documentation and a preliminary
LSM namespace for RFC. I've been suggested that there shouldn't be a
separate LSM namespace and that it should live within user namespace.
And this version does. This is a complete set of patches required for
Smack namespace.

This was designed with a collaboration of Smack maintainer Casey
Schaufler.

Smack namespace have been implemented using user namespace hooks added
by one of the patches. To put some context to it I paste here a
documentation on what Smack namespace wants to achieve.

LSM hooks themselves are documented in the security.h file inside the
patch.

The patches are based on:
https://github.com/cschaufler/smack-next/tree/smack-for-4.2-stacked

The tree with them is avaiable here:
https://github.com/Havner/smack-namespace/tree/smack-namespace-for-4.2-stacked-v2

Changes from v1:
 - "kernel/exit.c: make sure current's nsproxy != NULL while checking
   caps" patch has been dropped
 - fixed the title of the user_ns operations patch


===================================================================

--- What is a Smack namespace ---

Smack namespace was developed to make it possible for Smack to work
nicely with Linux containers where there is a full operating system
with its own init inside the namespace. Such a system working with
Smack expects to have at least partially working SMACK_MAC_ADMIN to be
able to change labels of processes and files. This is required to be
able to securely start applications under the control of Smack and
manage their access rights.

It was implemented using new LSM hooks added to the user namespace
that were developed together with Smack namespace.


--- Design ideas ---

"Smack namespace" is rather "Smack labels namespace" as not the whole
MAC is namespaced, only the labels. There is a great analogy between
Smack labels namespace and the user namespace part that remaps UIDs.

The idea is to create a map of labels for a namespace so the namespace
is only allowed to use those labels. Smack rules are always the same
as in the init namespace (limited only by what labels are mapped) and
cannot be manipulated from the child namespace. The map is actually
only for labels' names. The underlying structures for labels remain
the same. The filesystem also stores the "unmapped" labels from the
init namespace.

Let's say we have those labels in the init namespace:
label1
label2
label3

and those rules:
label1 label2 rwx
label1 label3 rwx
label2 label3 rwx

We create a map for a namespace:
label1 -> mapped1
label2 -> mapped2

This means that 'label3' is completely invisible in the namespace. As if
it didn't exist. All the rules that include it are ignored.

Effectively in the namespace we have only one rule:
mapped1 mapped2 rwx

Which in reality is:
label1 label2 rwx

All requests to access an object with a 'label3' will be denied. If it
ever comes to a situation where 'label3' would have to be printed
(e.g. reading an exec or mmap label from a file to which we have
access) then huh sign '?' will be printed instead.

All the operations in the namespace on the remaining labels will have
to be performed using their mapped names. Things like changing own
process's label, changing filesystem label. Labels will also be
printed with their mapped names.

You cannot import new labels in a namespace. Every operation that
would do so in an init namespace will return an error in the child
namespace. You cannot assign an unmapped or not existing label to an
object. You can only operate on labels that have been explicitly
mapped.


--- Capabilities ---

Enabling Smack related capabilities (CAP_MAC_ADMIN and
CAP_MAC_OVERRIDE) is main goal of Smack namespace, so it can work
properly in the container. And those capabilities do work to some
extent. In several places where capabilities are checked compatibility
with Smack namespace has been introduced. Capabilities are of course
limited to operate only on mapped labels.

CAP_MAC_OVERRIDE works fully, will allow you to ignore Smack access
rules, but only between objects that have labels mapped. So in the
example above having this CAP will allow e.g. label2 to write to
label1, but will not allow any access to label3.

With CAP_MAC_ADMIN the following operations has been allowed inside
the namespace:
- setting and removing xattr on files, including the security.* ones
- setting process's own label (/proc/self/attr/current)
- mounting in a privileged Smack mode, which means one can specify
  additional mount options like: smackfsdef, smackfsfloor etc.

Again this is also allowed only on the mapped labels. Labels on the
filesystem will be stored in unmapped form so they are preserved
through reboots.

Such a namespace construct allows e.g. systemd (with Smack support)
working in a container to assign labels properly to daemons and other
processes.


--- Usage ---

Smack namespace is written using LSM hooks inside user namespace. That
means it's connected to it.

To create a new Smack namespace you need to unshare() user namespace
as usual. If that is all you do though, than there is no difference to
what is now. To activate the Smack namespace you need to fill the
labels' map. It is in a file /proc/$PID/smack_map.

By default the map is empty and Smack namespaces are inactive (labels
are taken directly from a parent namespace). It also means that the
Smack capabilities will be inactive. After you fill the map it starts
to take effect in the namespace and Smack capabilities (only on mapped
labels) start to work.

Due to the way Smack works only CAP_MAC_ADMIN from the parent
namespace (init_user_ns for now, see the "Current limitations" below)
is allowed to fill the map. That means that an unprivileged user is
still allowed to create the user namespace but it will not be able to
fill the labels' map (activate Smack namespace). An administrator
intervention is required.

The attr_map write format is:
unmapped_label mapped_label

When reading the file it shows an active map for a namespace the
process in question is in in the format:
unmapped_label -> mapped_label

If the smack_map file is empty it means the namespace is not mapped
and Smack namespace is inactive (no mappings, MAC related capabilities
behave as they did before, meaning they are active only in
init_user_ns). For init_user_ns the map will always be empty.

Writing to the map file is not disabled after the first write as it is
in uid_map. For Smack we have no means to map ranges of labels, hence
it can really be advantageous to be able to expand the map later
on. But you can only add to the map. You cannot remove already mapped
labels. You cannot change the already existing mappings. Also mappings
has to be 1-1. All requests to create a map where either the unmapped
or the mapped label already exists in the map will be denied.

setns() with Smack namespace active has an additional check that the
label of a process that is calling setns() has to be already mapped in
the target Smack namespace for the call to succeed.


--- Special labels ---

Smack is using some special labels that have built-in rules. Things
like floor '_', dash '^', star '*', etc. Those labels are not
automatically mapped to the namespace. Moreover, you can choose to map
a different label from the init namespace to behave e.g. like floor
inside the namespace.

Let's say we have no rules and those labels in the init namespace:
_
floor_to_be
label

Both 'label' and 'floor_to_be' can read objects with '_'. But they
have no access rights to each other.

Now let's create a map like this:
_             ordinary_label
floor_to_be   _
label         mapped

Right now label 'mapped' can read label '_' which means that
effectively inside this namespace label 'label' has gained read access
to the 'floor_to_be'. The label 'ordinary_label' is exactly it, an
ordinary label that the built-in rules no longer apply to inside the
namespace.

To sum up, special labels in the namespace behave the same as in the
init namespace. Not the original special labels though, but the ones
we map to specials. This is the only case where a namespace can have
access rights the init namespace does not have (like the 'label' to
'floor_to_be' in the example above).

Of course mappings like these are perfectly legal:
_   _
*   *
^   ^


--- Current limitations ---

The Smack namespace is not hierarchical yet. It is currently not
possible to fill a smack_map of a nested user namespace (you can still
create nested user namespace, it will just inherit its parent's map
and won't have active Smack capabilities). When hierarchy will be
implemented the process creating another namespace will be allowed to
map only labels that it has permission to itself (those that it has in
its own map).

Special files inside the virtual smackfs needs to be reviewed whether
it's beneficial to have some of their functionality namespaced as well
(e.g. onlycap, syslog. ambient, etc). This would increase
CAP_MAC_ADMIN privileges inside the namespace.


Lukasz Pawelczyk (7):
  user_ns: 3 new hooks for user namespace operations
  smack: extend capability functions and fix 2 checks
  smack: abstraction layer for 2 common Smack operations
  smack: misc cleanups in preparation for a namespace patch
  smack: namespace groundwork
  smack: namespace implementation
  smack: documentation for the Smack namespace

 Documentation/security/00-INDEX            |   2 +
 Documentation/security/Smack-namespace.txt | 231 +++++++++++++
 MAINTAINERS                                |   1 +
 fs/proc/base.c                             |  57 +++
 include/linux/lsm_hooks.h                  |  28 ++
 include/linux/security.h                   |  23 ++
 include/linux/user_namespace.h             |   9 +
 kernel/user.c                              |   3 +
 kernel/user_namespace.c                    |  18 +
 security/security.c                        |  28 ++
 security/smack/Kconfig                     |  12 +
 security/smack/Makefile                    |   1 +
 security/smack/smack.h                     | 187 +++++++++-
 security/smack/smack_access.c              | 191 ++++++++--
 security/smack/smack_lsm.c                 | 536 ++++++++++++++++++++---------
 security/smack/smack_ns.c                  | 471 +++++++++++++++++++++++++
 security/smack/smackfs.c                   | 154 +++++----
 17 files changed, 1702 insertions(+), 250 deletions(-)
 create mode 100644 Documentation/security/Smack-namespace.txt
 create mode 100644 security/smack/smack_ns.c

-- 
2.1.0

Re: [PATCH 1/8] kernel/exit.c: make sure current's nsproxy != NULL while checking caps

[Eric W. Biederman]

Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> writes:

> There is a rare case where current's nsproxy might be NULL but we are
> required to check for credentials and capabilities. It sometimes happens
> during an exit_group() syscall while destroying user's session (logging
> out).
>
> My understanding is that while we have to lock the task to get task's
> nsproxy and check whether it's NULL, for the 'current' we don't have to
> and it's expected not to be NULL. There is a code in the kernel
> currently that does current->nsproxy->user_ns without any checks.
> And include/linux/nsproxy.h confirms that:
>
> 2. when accessing (i.e. reading) current task's namespaces - no
>    precautions should be taken - just dereference the pointers
>
> There seem to be no crash currently because of this, but with accessing
> nsproxy from LSM hooks there is. This is the backtrace:
>
> 0  smk_tskacc (task=0xffff88003b0b92e0, obj_known=0x2 <irq_stack_union+2>, mode=2, a=0xffff88003be53dd8) at security/smack/smack_access.c:261
> 1  0xffffffff8130e2aa in smk_curacc (obj_known=<optimized out>, mode=<optimized out>, a=<optimized out>) at security/smack/smack_access.c:318
> 2  0xffffffff8130a50d in smack_task_kill (p=0xffff88003b0b92e0, info=<optimized out>, sig=<optimized out>, secid=<optimized out>) at security/smack/smack_lsm.c:2071
> 3  0xffffffff812ea4f6 in security_task_kill (p=<optimized out>, info=<optimized out>, sig=<optimized out>, secid=<optimized out>) at security/security.c:952
> 4  0xffffffff8109ac80 in check_kill_permission (sig=15, info=0x0 <irq_stack_union>, t=0xffff88003b0b8000) at kernel/signal.c:796
> 5  0xffffffff8109d3ab in group_send_sig_info (sig=15, info=0x0 <irq_stack_union>, p=0xffff88003b0b8000) at kernel/signal.c:1296
> 6  0xffffffff8108e527 in forget_original_parent (father=<optimized out>) at kernel/exit.c:575
> 7  exit_notify (group_dead=<optimized out>, tsk=<optimized out>) at kernel/exit.c:606
> 8  do_exit (code=<optimized out>) at kernel/exit.c:775
> 9  0xffffffff8108ec0f in do_group_exit (exit_code=0) at kernel/exit.c:891
> 10 0xffffffff8108ec84 in SYSC_exit_group (error_code=<optimized out>) at kernel/exit.c:902
> 11 SyS_exit_group (error_code=<optimized out>) at kernel/exit.c:900
>
> This backtrace clearly shows that there is an LSM hook task_kill() that
> happens during an exit_group() syscall and that this happens after
> exit_task_namespaces(). LSM hooks with namespaces might need nsproxy to
> be able to check for capabilities. At this point this is impossible. The
> current's nsproxy is already NULL/destroyed.
>
> This is the case because exit_task_namespaces() is called before the
> exit_notify() where all of the above happens. This patch changes their
> order.

Nacked-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>

current->nsproxy->user_ns does not exist,
and changing where exit_task_namespaces is fragile and I am really not
interested in messing with it right now, to solve a problem that does
not exist.

>
> Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> ---
>  kernel/exit.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/exit.c b/kernel/exit.c
> index 22fcc05..da1bb18 100644
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -742,7 +742,6 @@ void do_exit(long code)
>  	exit_fs(tsk);
>  	if (group_dead)
>  		disassociate_ctty(1);
> -	exit_task_namespaces(tsk);
>  	exit_task_work(tsk);
>  	exit_thread();
>  
> @@ -763,6 +762,13 @@ void do_exit(long code)
>  
>  	TASKS_RCU(tasks_rcu_i = __srcu_read_lock(&tasks_rcu_exit_srcu));
>  	exit_notify(tsk, group_dead);
> +
> +	/*
> +	 * This should be after all things that potentially require
> +	 * process's namespaces (e.g. capability checks).
> +	 */
> +	exit_task_namespaces(tsk);
> +
>  	proc_exit_connector(tsk);
>  #ifdef CONFIG_NUMA
>  	task_lock(tsk);

Re: [PATCH 1/8] kernel/exit.c: make sure current's nsproxy != NULL while checking caps

[Lukasz Pawelczyk]

On sob, 2015-05-23 at 12:49 -0500, Eric W. Biederman wrote:
> Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> writes:
> 
> > There is a rare case where current's nsproxy might be NULL but we are
> > required to check for credentials and capabilities. It sometimes happens
> > during an exit_group() syscall while destroying user's session (logging
> > out).
> >
> > My understanding is that while we have to lock the task to get task's
> > nsproxy and check whether it's NULL, for the 'current' we don't have to
> > and it's expected not to be NULL. There is a code in the kernel
> > currently that does current->nsproxy->user_ns without any checks.
> > And include/linux/nsproxy.h confirms that:
> >
> > 2. when accessing (i.e. reading) current task's namespaces - no
> >    precautions should be taken - just dereference the pointers
> >
> > There seem to be no crash currently because of this, but with accessing
> > nsproxy from LSM hooks there is. This is the backtrace:
> >
> > 0  smk_tskacc (task=0xffff88003b0b92e0, obj_known=0x2 <irq_stack_union+2>, mode=2, a=0xffff88003be53dd8) at security/smack/smack_access.c:261
> > 1  0xffffffff8130e2aa in smk_curacc (obj_known=<optimized out>, mode=<optimized out>, a=<optimized out>) at security/smack/smack_access.c:318
> > 2  0xffffffff8130a50d in smack_task_kill (p=0xffff88003b0b92e0, info=<optimized out>, sig=<optimized out>, secid=<optimized out>) at security/smack/smack_lsm.c:2071
> > 3  0xffffffff812ea4f6 in security_task_kill (p=<optimized out>, info=<optimized out>, sig=<optimized out>, secid=<optimized out>) at security/security.c:952
> > 4  0xffffffff8109ac80 in check_kill_permission (sig=15, info=0x0 <irq_stack_union>, t=0xffff88003b0b8000) at kernel/signal.c:796
> > 5  0xffffffff8109d3ab in group_send_sig_info (sig=15, info=0x0 <irq_stack_union>, p=0xffff88003b0b8000) at kernel/signal.c:1296
> > 6  0xffffffff8108e527 in forget_original_parent (father=<optimized out>) at kernel/exit.c:575
> > 7  exit_notify (group_dead=<optimized out>, tsk=<optimized out>) at kernel/exit.c:606
> > 8  do_exit (code=<optimized out>) at kernel/exit.c:775
> > 9  0xffffffff8108ec0f in do_group_exit (exit_code=0) at kernel/exit.c:891
> > 10 0xffffffff8108ec84 in SYSC_exit_group (error_code=<optimized out>) at kernel/exit.c:902
> > 11 SyS_exit_group (error_code=<optimized out>) at kernel/exit.c:900
> >
> > This backtrace clearly shows that there is an LSM hook task_kill() that
> > happens during an exit_group() syscall and that this happens after
> > exit_task_namespaces(). LSM hooks with namespaces might need nsproxy to
> > be able to check for capabilities. At this point this is impossible. The
> > current's nsproxy is already NULL/destroyed.
> >
> > This is the case because exit_task_namespaces() is called before the
> > exit_notify() where all of the above happens. This patch changes their
> > order.
> 
> Nacked-by: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
> 
> current->nsproxy->user_ns does not exist,
> and changing where exit_task_namespaces is fragile and I am really not
> interested in messing with it right now, to solve a problem that does
> not exist.

I must have missed the moment where current->nsproxy->user_ns was
removed. I obviously even don't use it in my patches anymore (replaced
with cred->user_ns).

Back when I started to write my patches and wanted to use
current->nsproxy->user_ns in LSM hooks the problem was real.

Fortunately current->cred->user_ns does not exhibit the same issue. I'll
drop this patch.

Sorry for the confusion.


> 
> >
> > Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
> > ---
> >  kernel/exit.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/exit.c b/kernel/exit.c
> > index 22fcc05..da1bb18 100644
> > --- a/kernel/exit.c
> > +++ b/kernel/exit.c
> > @@ -742,7 +742,6 @@ void do_exit(long code)
> >  	exit_fs(tsk);
> >  	if (group_dead)
> >  		disassociate_ctty(1);
> > -	exit_task_namespaces(tsk);
> >  	exit_task_work(tsk);
> >  	exit_thread();
> >  
> > @@ -763,6 +762,13 @@ void do_exit(long code)
> >  
> >  	TASKS_RCU(tasks_rcu_i = __srcu_read_lock(&tasks_rcu_exit_srcu));
> >  	exit_notify(tsk, group_dead);
> > +
> > +	/*
> > +	 * This should be after all things that potentially require
> > +	 * process's namespaces (e.g. capability checks).
> > +	 */
> > +	exit_task_namespaces(tsk);
> > +
> >  	proc_exit_connector(tsk);
> >  #ifdef CONFIG_NUMA
> >  	task_lock(tsk);
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

[PATCH v2 1/7] user_ns: 3 new hooks for user namespace operations

[Lukasz Pawelczyk]

This commit implements 3 new LSM hooks that provide the means for LSMs
to embed their own security context within user namespace, effectively
creating some sort of a user_ns related security namespace.

The first one to take advantage of this mechanism is Smack.

The hooks has been documented in the in the security.h below.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 include/linux/lsm_hooks.h      | 28 ++++++++++++++++++++++++++++
 include/linux/security.h       | 23 +++++++++++++++++++++++
 include/linux/user_namespace.h |  4 ++++
 kernel/user.c                  |  3 +++
 kernel/user_namespace.c        | 18 ++++++++++++++++++
 security/security.c            | 28 ++++++++++++++++++++++++++++
 6 files changed, 104 insertions(+)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index f014f25..b6e0c3d 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1260,6 +1260,23 @@
  *	audit_rule_init.
  *	@rule contains the allocated rule
  *
+ * @userns_create:
+ *	Allocates and fills the security part of a new user namespace.
+ *	@ns points to a newly created user namespace.
+ *	Returns 0 or an error code.
+ *
+ * @userns_free:
+ *	Deallocates the security part of a user namespace.
+ *	@ns points to a user namespace about to be destroyed.
+ *
+ * @userns_setns:
+ *	Run during a setns syscall to add a process to an already existing
+ *	user namespace. Returning failure here will block the operation
+ *	requested from userspace (setns() with CLONE_NEWUSER).
+ *	@nsproxy contains a nsproxy to which the user namespace will be assigned.
+ *	@ns contains user namespace that is to be incorporated to the nsproxy.
+ *	Returns 0 or an error code.
+ *
  * @inode_notifysecctx:
  *	Notify the security module of what the security context of an inode
  *	should be.  Initializes the incore security context managed by the
@@ -1611,6 +1628,12 @@ union security_list_options {
 				struct audit_context *actx);
 	void (*audit_rule_free)(void *lsmrule);
 #endif /* CONFIG_AUDIT */
+
+#ifdef CONFIG_SECURITY
+	int (*userns_create)(struct user_namespace *ns);
+	void (*userns_free)(struct user_namespace *ns);
+	int (*userns_setns)(struct nsproxy *nsproxy, struct user_namespace *ns);
+#endif /* CONFIG_SECURITY */
 };
 
 struct security_hook_heads {
@@ -1822,6 +1845,11 @@ struct security_hook_heads {
 	struct list_head audit_rule_match;
 	struct list_head audit_rule_free;
 #endif /* CONFIG_AUDIT */
+#ifdef CONFIG_SECURITY
+	struct list_head userns_create;
+	struct list_head userns_free;
+	struct list_head userns_setns;
+#endif /* CONFIG_SECURITY */
 };
 
 /*
diff --git a/include/linux/security.h b/include/linux/security.h
index 8c8175d..ec17ae1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1583,6 +1583,29 @@ static inline void security_audit_rule_free(void *lsmrule)
 #endif /* CONFIG_SECURITY */
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_SECURITY
+int security_userns_create(struct user_namespace *ns);
+void security_userns_free(struct user_namespace *ns);
+int security_userns_setns(struct nsproxy *nsproxy, struct user_namespace *ns);
+
+#else
+
+static inline int security_userns_create(struct user_namespace *ns)
+{
+	return 0;
+}
+
+static inline void security_userns_free(struct user_namespace *ns)
+{ }
+
+static inline int security_userns_setns(struct nsproxy *nsproxy,
+					struct user_namespace *ns)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SECURITY */
+
 #ifdef CONFIG_SECURITYFS
 
 extern struct dentry *securityfs_create_file(const char *name, umode_t mode,
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 8297e5b..a9400cc 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -39,6 +39,10 @@ struct user_namespace {
 	struct key		*persistent_keyring_register;
 	struct rw_semaphore	persistent_keyring_register_sem;
 #endif
+
+#ifdef CONFIG_SECURITY
+	void *security;
+#endif
 };
 
 extern struct user_namespace init_user_ns;
diff --git a/kernel/user.c b/kernel/user.c
index b069ccb..ce5419e 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -59,6 +59,9 @@ struct user_namespace init_user_ns = {
 	.persistent_keyring_register_sem =
 	__RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem),
 #endif
+#ifdef CONFIG_SECURITY
+	.security = NULL,
+#endif
 };
 EXPORT_SYMBOL_GPL(init_user_ns);
 
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 4109f83..cadffb6 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -22,6 +22,7 @@
 #include <linux/ctype.h>
 #include <linux/projid.h>
 #include <linux/fs_struct.h>
+#include <linux/security.h>
 
 static struct kmem_cache *user_ns_cachep __read_mostly;
 static DEFINE_MUTEX(userns_state_mutex);
@@ -108,6 +109,15 @@ int create_user_ns(struct cred *new)
 
 	set_cred_user_ns(new, ns);
 
+#ifdef CONFIG_SECURITY
+	ret = security_userns_create(ns);
+	if (ret) {
+		ns_free_inum(&ns->ns);
+		kmem_cache_free(user_ns_cachep, ns);
+		return ret;
+	}
+#endif
+
 #ifdef CONFIG_PERSISTENT_KEYRINGS
 	init_rwsem(&ns->persistent_keyring_register_sem);
 #endif
@@ -143,6 +153,9 @@ void free_user_ns(struct user_namespace *ns)
 #ifdef CONFIG_PERSISTENT_KEYRINGS
 		key_put(ns->persistent_keyring_register);
 #endif
+#ifdef CONFIG_SECURITY
+		security_userns_free(ns);
+#endif
 		ns_free_inum(&ns->ns);
 		kmem_cache_free(user_ns_cachep, ns);
 		ns = parent;
@@ -969,6 +982,7 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
 {
 	struct user_namespace *user_ns = to_user_ns(ns);
 	struct cred *cred;
+	int err;
 
 	/* Don't allow gaining capabilities by reentering
 	 * the same user namespace.
@@ -986,6 +1000,10 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
 	if (!ns_capable(user_ns, CAP_SYS_ADMIN))
 		return -EPERM;
 
+	err = security_userns_setns(nsproxy, user_ns);
+	if (err)
+		return err;
+
 	cred = prepare_creds();
 	if (!cred)
 		return -ENOMEM;
diff --git a/security/security.c b/security/security.c
index bd4c5f6..e902f3b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -25,6 +25,7 @@
 #include <linux/mount.h>
 #include <linux/personality.h>
 #include <linux/backing-dev.h>
+#include <linux/user_namespace.h>
 #include <net/flow.h>
 
 #define MAX_LSM_EVM_XATTR	2
@@ -1541,6 +1542,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
 }
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_SECURITY
+
+int security_userns_create(struct user_namespace *ns)
+{
+	return call_int_hook(userns_create, 0, ns);
+}
+
+void security_userns_free(struct user_namespace *ns)
+{
+	call_void_hook(userns_free, ns);
+}
+
+int security_userns_setns(struct nsproxy *nsproxy, struct user_namespace *ns)
+{
+	return call_int_hook(userns_setns, 0, nsproxy, ns);
+}
+
+#endif /* CONFIG_SECURITY */
+
 struct security_hook_heads security_hook_heads = {
 	.binder_set_context_mgr =
 		LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr),
@@ -1885,4 +1905,12 @@ struct security_hook_heads security_hook_heads = {
 	.audit_rule_free =
 		LIST_HEAD_INIT(security_hook_heads.audit_rule_free),
 #endif /* CONFIG_AUDIT */
+#ifdef CONFIG_SECURITY
+	.userns_create =
+		LIST_HEAD_INIT(security_hook_heads.userns_create),
+	.userns_free =
+		LIST_HEAD_INIT(security_hook_heads.userns_free),
+	.userns_setns =
+		LIST_HEAD_INIT(security_hook_heads.userns_setns),
+#endif /* CONFIG_SECURITY */
 };
-- 
2.1.0

[PATCH v2 2/7] smack: extend capability functions and fix 2 checks

[Lukasz Pawelczyk]

This patch extends smack capability functions to a full list to those
equivalent in the kernel

has_ns_capability -> smack_has_ns_privilege
has_capability    -> smack_has_privilege
ns_capable        -> smack_ns_privileged
capable           -> smack_privileged

It also puts the smack related part to a common function:
smack_capability_allowed()

Those functions will be needed for capability checks in the upcoming
Smack namespace patches.

Additionally there were 2 smack capability checks that used generic
capability functions instead of specific Smack ones effectively ignoring
the onlycap rule. This has been fixed now with the introduction of those
new functions.

This has implications on the Smack namespace as well as the additional
Smack checks in smack_capability_allowed() will be extended beyond the
onlycap rule. Not using Smack specific checks in those 2 places could
mean breaking the Smack label namespace separation.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h     | 63 +++++++++++++++++++++++++++++++++++++++++++---
 security/smack/smack_lsm.c |  4 +--
 2 files changed, 61 insertions(+), 6 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index b8c1a86..fa8fa87 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -332,21 +332,76 @@ static inline struct smack_known *smk_of_current(void)
 }
 
 /*
+ * Internal smack capability check complimentary to the
+ * set of kernel capable() and has_capability() functions
+ *
+ * For a capability in smack related checks to be effective it needs to:
+ * - have empty onlycap or the current label be the same as onlycap
+ * - be in the initial user ns
+ */
+static inline int smack_capability_allowed(struct smack_known *skp,
+					   struct user_namespace *user_ns)
+{
+	if (user_ns != &init_user_ns)
+		return 0;
+
+	if (smack_onlycap != NULL && smack_onlycap != skp)
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Is the task privileged in a namespace and allowed to be privileged
+ * by additional smack rules.
+ */
+static inline int smack_has_ns_privilege(struct task_struct *task,
+					 struct user_namespace *user_ns,
+					 int cap)
+{
+	struct smack_known *skp = smk_of_task_struct(task);
+
+	if (!has_ns_capability(task, user_ns, cap))
+		return 0;
+	if (smack_capability_allowed(skp, user_ns))
+		return 1;
+	return 0;
+}
+
+/*
  * Is the task privileged and allowed to be privileged
- * by the onlycap rule.
+ * by additional smack rules.
  */
-static inline int smack_privileged(int cap)
+static inline int smack_has_privilege(struct task_struct *task, int cap)
+{
+	return smack_has_ns_privilege(task, &init_user_ns, cap);
+}
+
+/*
+ * Is the current task privileged in a namespace and allowed to be privileged
+ * by additional smack rules.
+ */
+static inline int smack_ns_privileged(struct user_namespace *user_ns, int cap)
 {
 	struct smack_known *skp = smk_of_current();
 
-	if (!capable(cap))
+	if (!ns_capable(user_ns, cap))
 		return 0;
-	if (smack_onlycap == NULL || smack_onlycap == skp)
+	if (smack_capability_allowed(skp, user_ns))
 		return 1;
 	return 0;
 }
 
 /*
+ * Is the current task privileged and allowed to be privileged
+ * by additional smack rules.
+ */
+static inline int smack_privileged(int cap)
+{
+	return smack_ns_privileged(&init_user_ns, cap);
+}
+
+/*
  * logging functions
  */
 #define SMACK_AUDIT_DENIED 0x1
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a143328..ee7bb63 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -403,7 +403,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
 			rc = -EACCES;
-		else if (capable(CAP_SYS_PTRACE))
+		else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
 			rc = 0;
 		else
 			rc = -EACCES;
@@ -1646,7 +1646,7 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 	skp = file->f_security;
 	rc = smk_access(skp, tkp, MAY_WRITE, NULL);
 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc);
-	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))
+	if (rc != 0 && smack_has_privilege(tsk, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
-- 
2.1.0

[PATCH v2 3/7] smack: abstraction layer for 2 common Smack operations

[Lukasz Pawelczyk]

This patch adds two new functions that provide an abstraction layer for
two common internal Smack operations:

smk_find_label_name() - returns a label name (char*) from a struct
                        smack_known pointer
smk_get_label()       - either finds or imports a label from a raw label
                        name (char*) and returns struct smack_known point

This patch also simplifies some pieces of code due to addition of those
2 functions (e.g. smack_inode_post_setxattr, smk_fill_rule,
smk_write_revoke_subj).

It is meant as a preparation for namespaces patches. Those 2 functions
will serve as entry points for namespace operations.

This patch should not change the Smack behaviour in any way.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h        |   2 +
 security/smack/smack_access.c |  40 ++++++++++++
 security/smack/smack_lsm.c    |  76 ++++++++++++-----------
 security/smack/smackfs.c      | 137 ++++++++++++++++++++++--------------------
 4 files changed, 155 insertions(+), 100 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index fa8fa87..fa32495 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -249,6 +249,8 @@ int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 struct smack_known *smk_import_entry(const char *, int);
 void smk_insert_entry(struct smack_known *skp);
 struct smack_known *smk_find_entry(const char *);
+char *smk_find_label_name(struct smack_known *skp);
+struct smack_known *smk_get_label(const char *string, int len, bool import);
 
 /*
  * Shared data.
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 408e20b..3bf4cad 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -617,3 +617,43 @@ struct smack_known *smack_from_secid(const u32 secid)
 	rcu_read_unlock();
 	return &smack_known_invalid;
 }
+
+/**
+ * smk_find_label_name - A helper to get a string value of a label
+ * @skp: a label we want a string value from
+ *
+ * Returns a pointer to a label name or NULL if label name not found.
+ */
+char *smk_find_label_name(struct smack_known *skp)
+{
+	return skp->smk_known;
+}
+
+/**
+ * smk_get_label - A helper to get the smack_known value from a string using
+ *                 either import or find functions if it already exists
+ * @string: a name of a label we look for or want to import
+ * @len: the string size, or zero if it is NULL terminated
+ * @import: whether we should import the label if not found
+ *
+ * Returns a smack_known label that is either imported or found.
+ * NULL if label not found (only when import == false).
+ * Error code otherwise.
+ */
+struct smack_known *smk_get_label(const char *string, int len, bool import)
+{
+	struct smack_known *skp;
+	char *cp;
+
+	if (import) {
+		skp = smk_import_entry(string, len);
+	} else {
+		cp = smk_parse_smack(string, len);
+		if (IS_ERR(cp))
+			return ERR_CAST(cp);
+
+		skp = smk_find_entry(cp);
+	}
+
+	return skp;
+}
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index ee7bb63..4a197b6 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -608,7 +608,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
 			op += strlen(SMK_FSHAT);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_hat = skp;
@@ -616,7 +616,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
 			op += strlen(SMK_FSFLOOR);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_floor = skp;
@@ -625,7 +625,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		} else if (strncmp(op, SMK_FSDEFAULT,
 				   strlen(SMK_FSDEFAULT)) == 0) {
 			op += strlen(SMK_FSDEFAULT);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_default = skp;
@@ -633,7 +633,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
 			op += strlen(SMK_FSROOT);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -641,7 +641,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
 			op += strlen(SMK_FSTRANS);
-			skp = smk_import_entry(op, 0);
+			skp = smk_get_label(op, 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -1125,7 +1125,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 		rc = -EPERM;
 
 	if (rc == 0 && check_import) {
-		skp = size ? smk_import_entry(value, size) : NULL;
+		skp = size ? smk_get_label(value, size, true) : NULL;
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else if (skp == NULL || (check_star &&
@@ -1159,6 +1159,7 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 				      const void *value, size_t size, int flags)
 {
 	struct smack_known *skp;
+	struct smack_known **skpp = NULL;
 	struct inode_smack *isp = d_backing_inode(dentry)->i_security;
 
 	if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
@@ -1166,27 +1167,21 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 		return;
 	}
 
-	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
-		skp = smk_import_entry(value, size);
-		if (!IS_ERR(skp))
-			isp->smk_inode = skp;
-		else
-			isp->smk_inode = &smack_known_invalid;
-	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
-		skp = smk_import_entry(value, size);
-		if (!IS_ERR(skp))
-			isp->smk_task = skp;
-		else
-			isp->smk_task = &smack_known_invalid;
-	} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
-		skp = smk_import_entry(value, size);
+	if (strcmp(name, XATTR_NAME_SMACK) == 0)
+		skpp = &isp->smk_inode;
+	else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0)
+		skpp = &isp->smk_task;
+	else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
+		skpp = &isp->smk_mmap;
+
+	if (skpp) {
+		skp = smk_get_label(value, size, true);
+
 		if (!IS_ERR(skp))
-			isp->smk_mmap = skp;
+			*skpp = skp;
 		else
-			isp->smk_mmap = &smack_known_invalid;
+			*skpp = &smack_known_invalid;
 	}
-
-	return;
 }
 
 /**
@@ -1280,15 +1275,17 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	struct socket *sock;
 	struct super_block *sbp;
 	struct inode *ip = (struct inode *)inode;
-	struct smack_known *isp;
-	int ilen;
+	struct smack_known *isp = NULL;
 	int rc = 0;
 
-	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
+	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0)
 		isp = smk_of_inode(inode);
-		ilen = strlen(isp->smk_known);
-		*buffer = isp->smk_known;
-		return ilen;
+
+	if (isp) {
+		*buffer = smk_find_label_name(isp);
+		if (*buffer == NULL)
+			*buffer = smack_known_huh.smk_known;
+		return strlen(*buffer);
 	}
 
 	/*
@@ -1311,10 +1308,11 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	else
 		return -EOPNOTSUPP;
 
-	ilen = strlen(isp->smk_known);
 	if (rc == 0) {
-		*buffer = isp->smk_known;
-		rc = ilen;
+		*buffer = smk_find_label_name(isp);
+		if (*buffer == NULL)
+			*buffer = smack_known_huh.smk_known;
+		rc = strlen(*buffer);
 	}
 
 	return rc;
@@ -3270,7 +3268,10 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	cp = kstrdup(skp->smk_known, GFP_KERNEL);
+	cp = smk_find_label_name(skp);
+	if (cp == NULL)
+		cp = smack_known_huh.smk_known;
+	cp = kstrdup(cp, GFP_KERNEL);
 	if (cp == NULL)
 		return -ENOMEM;
 
@@ -3314,7 +3315,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	skp = smk_import_entry(value, size);
+	skp = smk_get_label(value, size, true);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
 
@@ -4042,7 +4043,10 @@ static int smack_key_getsecurity(struct key *key, char **_buffer)
 		return 0;
 	}
 
-	copy = kstrdup(skp->smk_known, GFP_KERNEL);
+	copy = smk_find_label_name(skp);
+	if (copy == NULL)
+		copy = smack_known_huh.smk_known;
+	copy = kstrdup(copy, GFP_KERNEL);
 	if (copy == NULL)
 		return -ENOMEM;
 	length = strlen(copy) + 1;
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 3e42426..5ec1e8e 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -345,36 +345,17 @@ static int smk_fill_rule(const char *subject, const char *object,
 				struct smack_parsed_rule *rule, int import,
 				int len)
 {
-	const char *cp;
-	struct smack_known *skp;
-
-	if (import) {
-		rule->smk_subject = smk_import_entry(subject, len);
-		if (IS_ERR(rule->smk_subject))
-			return PTR_ERR(rule->smk_subject);
-
-		rule->smk_object = smk_import_entry(object, len);
-		if (IS_ERR(rule->smk_object))
-			return PTR_ERR(rule->smk_object);
-	} else {
-		cp = smk_parse_smack(subject, len);
-		if (IS_ERR(cp))
-			return PTR_ERR(cp);
-		skp = smk_find_entry(cp);
-		kfree(cp);
-		if (skp == NULL)
-			return -ENOENT;
-		rule->smk_subject = skp;
-
-		cp = smk_parse_smack(object, len);
-		if (IS_ERR(cp))
-			return PTR_ERR(cp);
-		skp = smk_find_entry(cp);
-		kfree(cp);
-		if (skp == NULL)
-			return -ENOENT;
-		rule->smk_object = skp;
-	}
+	rule->smk_subject = smk_get_label(subject, len, import);
+	if (IS_ERR(rule->smk_subject))
+		return PTR_ERR(rule->smk_subject);
+	if (rule->smk_subject == NULL)
+		return -ENOENT;
+
+	rule->smk_object = smk_get_label(object, len, import);
+	if (IS_ERR(rule->smk_object))
+		return PTR_ERR(rule->smk_object);
+	if (rule->smk_object == NULL)
+		return -ENOENT;
 
 	rule->smk_access1 = smk_perm_from_str(access1);
 	if (access2)
@@ -605,6 +586,9 @@ static void smk_seq_stop(struct seq_file *s, void *v)
 
 static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 {
+	char *sbj;
+	char *obj;
+
 	/*
 	 * Don't show any rules with label names too long for
 	 * interface file (/smack/load or /smack/load2)
@@ -618,9 +602,13 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	if (srp->smk_access == 0)
 		return;
 
-	seq_printf(s, "%s %s",
-		   srp->smk_subject->smk_known,
-		   srp->smk_object->smk_known);
+	sbj = smk_find_label_name(srp->smk_subject);
+	obj = smk_find_label_name(srp->smk_object);
+
+	if (sbj == NULL || obj == NULL)
+		return;
+
+	seq_printf(s, "%s %s", sbj, obj);
 
 	seq_putc(s, ' ');
 
@@ -811,6 +799,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
 	char sep = '/';
+	char *cp;
 	int i;
 
 	/*
@@ -824,7 +813,11 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	if (strlen(skp->smk_known) >= SMK_LABELLEN)
 		return 0;
 
-	seq_printf(s, "%s %3d", skp->smk_known, skp->smk_netlabel.attr.mls.lvl);
+	cp = smk_find_label_name(skp);
+	if (cp == NULL)
+		return 0;
+
+	seq_printf(s, "%s %3d", cp, skp->smk_netlabel.attr.mls.lvl);
 
 	for (i = netlbl_catmap_walk(cmp, 0); i >= 0;
 	     i = netlbl_catmap_walk(cmp, i + 1)) {
@@ -913,7 +906,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 	 */
 	mutex_lock(&smack_cipso_lock);
 
-	skp = smk_import_entry(rule, 0);
+	skp = smk_get_label(rule, 0, true);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -1002,9 +995,14 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
 	char sep = '/';
+	char *cp;
 	int i;
 
-	seq_printf(s, "%s %3d", skp->smk_known, skp->smk_netlabel.attr.mls.lvl);
+	cp = smk_find_label_name(skp);
+	if (cp == NULL)
+		return 0;
+
+	seq_printf(s, "%s %3d", cp, skp->smk_netlabel.attr.mls.lvl);
 
 	for (i = netlbl_catmap_walk(cmp, 0); i >= 0;
 	     i = netlbl_catmap_walk(cmp, i + 1)) {
@@ -1087,11 +1085,15 @@ static int netlbladdr_seq_show(struct seq_file *s, void *v)
 	unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
 	int maskn;
 	u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
+	char *label = smk_find_label_name(skp->smk_label);
+
+	if (label == NULL)
+		return 0;
 
 	for (maskn = 0; temp_mask; temp_mask <<= 1, maskn++);
 
 	seq_printf(s, "%u.%u.%u.%u/%d %s\n",
-		hp[0], hp[1], hp[2], hp[3], maskn, skp->smk_label->smk_known);
+		hp[0], hp[1], hp[2], hp[3], maskn, label);
 
 	return 0;
 }
@@ -1237,7 +1239,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	 * If smack begins with '-', it is an option, don't import it
 	 */
 	if (smack[0] != '-') {
-		skp = smk_import_entry(smack, 0);
+		skp = smk_get_label(smack, 0, true);
 		if (IS_ERR(skp)) {
 			rc = PTR_ERR(skp);
 			goto free_out;
@@ -1566,6 +1568,7 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
 	ssize_t rc;
+	char *cp;
 	int asize;
 
 	if (*ppos != 0)
@@ -1576,12 +1579,14 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 	 */
 	mutex_lock(&smack_ambient_lock);
 
-	asize = strlen(smack_net_ambient->smk_known) + 1;
+	cp = smk_find_label_name(smack_net_ambient);
+	if (cp == NULL)
+		cp = smack_known_huh.smk_known;
+
+	asize = strlen(cp) + 1;
 
 	if (cn >= asize)
-		rc = simple_read_from_buffer(buf, cn, ppos,
-					     smack_net_ambient->smk_known,
-					     asize);
+		rc = simple_read_from_buffer(buf, cn, ppos, cp, asize);
 	else
 		rc = -EINVAL;
 
@@ -1619,7 +1624,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 		goto out;
 	}
 
-	skp = smk_import_entry(data, count);
+	skp = smk_get_label(data, count, true);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -1663,8 +1668,11 @@ static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
 	if (*ppos != 0)
 		return 0;
 
-	if (smack_onlycap != NULL)
-		smack = smack_onlycap->smk_known;
+	if (smack_onlycap != NULL) {
+		smack = smk_find_label_name(smack_onlycap);
+		if (smack == NULL)
+			smack = smack_known_huh.smk_known;
+	}
 
 	asize = strlen(smack) + 1;
 
@@ -1719,7 +1727,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_import_entry(data, count);
+	skp = smk_get_label(data, count, true);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -1760,8 +1768,11 @@ static ssize_t smk_read_unconfined(struct file *filp, char __user *buf,
 	if (*ppos != 0)
 		return 0;
 
-	if (smack_unconfined != NULL)
-		smack = smack_unconfined->smk_known;
+	if (smack_unconfined != NULL) {
+		smack = smk_find_label_name(smack_unconfined);
+		if (smack == NULL)
+			smack = smack_known_huh.smk_known;
+	}
 
 	asize = strlen(smack) + 1;
 
@@ -1808,7 +1819,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_import_entry(data, count);
+	skp = smk_get_label(data, count, true);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -2205,7 +2216,6 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
 	char *data = NULL;
-	const char *cp = NULL;
 	struct smack_known *skp;
 	struct smack_rule *sp;
 	struct list_head *rule_list;
@@ -2230,13 +2240,11 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 		goto free_out;
 	}
 
-	cp = smk_parse_smack(data, count);
-	if (IS_ERR(cp)) {
-		rc = PTR_ERR(cp);
+	skp = smk_get_label(data, count, false);
+	if (IS_ERR(skp)) {
+		rc = PTR_ERR(skp);
 		goto free_out;
 	}
-
-	skp = smk_find_entry(cp);
 	if (skp == NULL)
 		goto free_out;
 
@@ -2252,7 +2260,6 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 
 free_out:
 	kfree(data);
-	kfree(cp);
 	return rc;
 }
 
@@ -2315,23 +2322,25 @@ static const struct file_operations smk_change_rule_ops = {
 static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
-	struct smack_known *skp;
 	ssize_t rc = -EINVAL;
+	char *cp;
 	int asize;
 
 	if (*ppos != 0)
 		return 0;
 
 	if (smack_syslog_label == NULL)
-		skp = &smack_known_star;
-	else
-		skp = smack_syslog_label;
+		cp = smack_known_star.smk_known;
+	else {
+		cp = smk_find_label_name(smack_syslog_label);
+		if (cp == NULL)
+			cp = smack_known_huh.smk_known;
+	}
 
-	asize = strlen(skp->smk_known) + 1;
+	asize = strlen(cp) + 1;
 
 	if (cn >= asize)
-		rc = simple_read_from_buffer(buf, cn, ppos, skp->smk_known,
-						asize);
+		rc = simple_read_from_buffer(buf, cn, ppos, cp, asize);
 
 	return rc;
 }
@@ -2362,7 +2371,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (copy_from_user(data, buf, count) != 0)
 		rc = -EFAULT;
 	else {
-		skp = smk_import_entry(data, count);
+		skp = smk_get_label(data, count, true);
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else
-- 
2.1.0

[PATCH v2 4/7] smack: misc cleanups in preparation for a namespace patch

[Lukasz Pawelczyk]

This patch does some small miscellaneous cleanups and additions that
should not change the code behaviour in any way. Its only purpose is to
shape the code in a way that the smack namespace patches would be
smaller and easier to understand.

Changes:
- two small functions added
- one macro has been moved to a header
- minor code reformatting in several places for readability
- unnecessarily increasing string size has been fixed

This patch should not change the behaviour of the Smack in any way.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h        | 25 ++++++++++++++++++-
 security/smack/smack_access.c | 18 +++++++++-----
 security/smack/smack_lsm.c    | 58 ++++++++++++++++---------------------------
 3 files changed, 58 insertions(+), 43 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index fa32495..3818d19 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -229,6 +229,7 @@ struct smk_audit_info {
 	struct smack_audit_data sad;
 #endif
 };
+
 /*
  * These functions are in smack_lsm.c
  */
@@ -240,7 +241,7 @@ struct inode_smack *new_inode_smack(struct smack_known *);
 int smk_access_entry(char *, char *, struct list_head *);
 int smk_access(struct smack_known *, struct smack_known *,
 	       int, struct smk_audit_info *);
-int smk_tskacc(struct task_smack *, struct smack_known *,
+int smk_tskacc(struct task_struct *, struct smack_known *,
 	       u32, struct smk_audit_info *);
 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 struct smack_known *smack_from_secid(const u32);
@@ -287,6 +288,7 @@ extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
 static inline int smk_inode_transmutable(const struct inode *isp)
 {
 	struct inode_smack *sip = isp->i_security;
+
 	return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
 }
 
@@ -296,10 +298,31 @@ static inline int smk_inode_transmutable(const struct inode *isp)
 static inline struct smack_known *smk_of_inode(const struct inode *isp)
 {
 	struct inode_smack *sip = isp->i_security;
+
 	return sip->smk_inode;
 }
 
 /*
+ * Present a pointer to the smack label entry in an inode blob for an exec.
+ */
+static inline struct smack_known *smk_of_exec(const struct inode *isp)
+{
+	struct inode_smack *sip = isp->i_security;
+
+	return sip->smk_task;
+}
+
+/*
+ * Present a pointer to the smack label entry in an inode blob for an mmap.
+ */
+static inline struct smack_known *smk_of_mmap(const struct inode *isp)
+{
+	struct inode_smack *sip = isp->i_security;
+
+	return sip->smk_mmap;
+}
+
+/*
  * Present a pointer to the smack label entry in an task blob.
  */
 static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 3bf4cad..47a9c92 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -167,6 +167,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 		if (subject == &smack_known_hat)
 			goto out_audit;
 	}
+
 	/*
 	 * Beyond here an explicit relationship is required.
 	 * If the requested access is contained in the available
@@ -183,6 +184,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 		rc = -EACCES;
 		goto out_audit;
 	}
+
 #ifdef CONFIG_SECURITY_SMACK_BRINGUP
 	/*
 	 * Return a positive value if using bringup mode.
@@ -225,10 +227,10 @@ out_audit:
  * non zero otherwise. It allows that the task may have the capability
  * to override the rules.
  */
-int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
+int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
 	       u32 mode, struct smk_audit_info *a)
 {
-	struct smack_known *sbj_known = smk_of_task(tsp);
+	struct smack_known *sbj_known = smk_of_task_struct(task);
 	int may;
 	int rc;
 
@@ -237,13 +239,19 @@ int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
 	 */
 	rc = smk_access(sbj_known, obj_known, mode, NULL);
 	if (rc >= 0) {
+		struct task_smack *tsp;
+
 		/*
 		 * If there is an entry in the task's rule list
 		 * it can further restrict access.
 		 */
+		rcu_read_lock();
+		tsp = __task_cred(task)->security;
 		may = smk_access_entry(sbj_known->smk_known,
 				       obj_known->smk_known,
 				       &tsp->smk_rules);
+		rcu_read_unlock();
+
 		if (may < 0)
 			goto out_audit;
 		if ((mode & may) == mode)
@@ -280,9 +288,7 @@ out_audit:
 int smk_curacc(struct smack_known *obj_known,
 	       u32 mode, struct smk_audit_info *a)
 {
-	struct task_smack *tsp = current_security();
-
-	return smk_tskacc(tsp, obj_known, mode, a);
+	return smk_tskacc(current, obj_known, mode, a);
 }
 
 #ifdef CONFIG_AUDIT
@@ -456,7 +462,7 @@ char *smk_parse_smack(const char *string, int len)
 	int i;
 
 	if (len <= 0)
-		len = strlen(string) + 1;
+		len = strlen(string);
 
 	/*
 	 * Reserve a leading '-' as an indicator that
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4a197b6..bb74ca9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -383,8 +383,6 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 {
 	int rc;
 	struct smk_audit_info ad, *saip = NULL;
-	struct task_smack *tsp;
-	struct smack_known *tracer_known;
 
 	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
 		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
@@ -392,13 +390,12 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 		saip = &ad;
 	}
 
-	rcu_read_lock();
-	tsp = __task_cred(tracer)->security;
-	tracer_known = smk_of_task(tsp);
 
 	if ((mode & PTRACE_MODE_ATTACH) &&
 	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
 	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
+		struct smack_known *tracer_known = smk_of_task_struct(tracer);
+
 		if (tracer_known->smk_known == tracee_known->smk_known)
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
@@ -406,22 +403,18 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 		else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
 			rc = 0;
 		else
-			rc = -EACCES;
+			rc = -EPERM;
 
 		if (saip)
 			smack_log(tracer_known->smk_known,
 				  tracee_known->smk_known,
 				  0, rc, saip);
 
-		rcu_read_unlock();
 		return rc;
 	}
 
 	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
-	rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
-
-	rcu_read_unlock();
-	return rc;
+	return smk_tskacc(tracer, tracee_known, smk_ptrace_mode(mode), saip);
 }
 
 /*
@@ -440,9 +433,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
  */
 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 {
-	struct smack_known *skp;
-
-	skp = smk_of_task_struct(ctp);
+	struct smack_known *skp = smk_of_task_struct(ctp);
 
 	return smk_ptrace_rule_check(current, skp, mode, __func__);
 }
@@ -457,13 +448,9 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
  */
 static int smack_ptrace_traceme(struct task_struct *ptp)
 {
-	int rc;
-	struct smack_known *skp;
-
-	skp = smk_of_task(current_security());
+	struct smack_known *skp = smk_of_current();
 
-	rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
-	return rc;
+	return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
 }
 
 /**
@@ -1529,13 +1516,14 @@ static int smack_mmap_file(struct file *file,
 	if (file == NULL)
 		return 0;
 
+	tsp = current_security();
+	skp = smk_of_task(tsp);
 	isp = file_inode(file)->i_security;
-	if (isp->smk_mmap == NULL)
-		return 0;
 	mkp = isp->smk_mmap;
 
-	tsp = current_security();
-	skp = smk_of_current();
+	if (mkp == NULL)
+		return 0;
+
 	rc = 0;
 
 	rcu_read_lock();
@@ -3348,11 +3336,13 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 static int smack_unix_stream_connect(struct sock *sock,
 				     struct sock *other, struct sock *newsk)
 {
-	struct smack_known *skp;
-	struct smack_known *okp;
 	struct socket_smack *ssp = sock->sk_security;
 	struct socket_smack *osp = other->sk_security;
 	struct socket_smack *nsp = newsk->sk_security;
+	struct smack_known *skp_out = ssp->smk_out;
+	struct smack_known *okp_out = osp->smk_out;
+	struct smack_known *skp_in = ssp->smk_in;
+	struct smack_known *okp_in = osp->smk_in;
 	struct smk_audit_info ad;
 	int rc = 0;
 #ifdef CONFIG_AUDIT
@@ -3360,19 +3350,15 @@ static int smack_unix_stream_connect(struct sock *sock,
 #endif
 
 	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
-		skp = ssp->smk_out;
-		okp = osp->smk_in;
 #ifdef CONFIG_AUDIT
 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
 		smk_ad_setfield_u_net_sk(&ad, other);
 #endif
-		rc = smk_access(skp, okp, MAY_WRITE, &ad);
-		rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
+		rc = smk_access(skp_out, okp_in, MAY_WRITE, &ad);
+		rc = smk_bu_note("UDS connect", skp_out, okp_in, MAY_WRITE, rc);
 		if (rc == 0) {
-			okp = osp->smk_out;
-			skp = ssp->smk_in;
-			rc = smk_access(okp, skp, MAY_WRITE, &ad);
-			rc = smk_bu_note("UDS connect", okp, skp,
+			rc = smk_access(okp_out, skp_in, MAY_WRITE, &ad);
+			rc = smk_bu_note("UDS connect", okp_out, skp_in,
 						MAY_WRITE, rc);
 		}
 	}
@@ -3381,8 +3367,8 @@ static int smack_unix_stream_connect(struct sock *sock,
 	 * Cross reference the peer labels for SO_PEERSEC.
 	 */
 	if (rc == 0) {
-		nsp->smk_packet = ssp->smk_out;
-		ssp->smk_packet = osp->smk_out;
+		nsp->smk_packet = skp_out;
+		ssp->smk_packet = okp_out;
 	}
 
 	return rc;
-- 
2.1.0

[PATCH v2 5/7] smack: namespace groundwork

[Lukasz Pawelczyk]

This commit introduces several changes to Smack to prepare it for
namespace implementation. All the changes are related to namespaces.

Overview of the changes:
- Adds required data structures for mapped labels and functions to
  operate on them.
- Implements the proc interface /proc/$PID/smack_map that can be used for
  remapping of labels for a specific namespace. Also for checking the map.
- Modifies handling of special built-in labels. Detects them on import
  and assigns the same char* pointer regardless whether it's used in a
  normal or a mapped label. This way we can always compare them by ==
  instead of strcmp().
- Adds User namespace hooks implementation

This patch introduces both internal and user-space visible APIs to
handle namespaced labels and Smack namespaces but the behaviour of Smack
should not be changed. The APIs are there, but they have no impact yet.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 fs/proc/base.c                 |  57 ++++++
 include/linux/user_namespace.h |   5 +
 security/smack/Kconfig         |  10 +
 security/smack/Makefile        |   1 +
 security/smack/smack.h         |  42 +++-
 security/smack/smack_access.c  |  46 ++++-
 security/smack/smack_lsm.c     |  76 ++++++++
 security/smack/smack_ns.c      | 432 +++++++++++++++++++++++++++++++++++++++++
 8 files changed, 662 insertions(+), 7 deletions(-)
 create mode 100644 security/smack/smack_ns.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 093ca14..22dde1c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2529,6 +2529,57 @@ static const struct file_operations proc_setgroups_operations = {
 };
 #endif /* CONFIG_USER_NS */
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+static int proc_smack_map_open(struct inode *inode, struct file *file)
+{
+	struct user_namespace *ns = NULL;
+	struct task_struct *task;
+	struct seq_file *seq;
+	int ret = -EINVAL;
+
+	task = get_proc_task(inode);
+	if (task) {
+		rcu_read_lock();
+		ns = get_user_ns(task_cred_xxx(task, user_ns));
+		rcu_read_unlock();
+		put_task_struct(task);
+	}
+	if (!ns)
+		goto err;
+
+	ret = seq_open(file, &proc_smack_map_seq_operations);
+	if (ret)
+		goto err_put_ns;
+
+	seq = file->private_data;
+	seq->private = ns;
+
+	return 0;
+
+err_put_ns:
+	put_user_ns(ns);
+err:
+	return ret;
+}
+
+static int proc_smack_map_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+
+	put_user_ns(ns);
+	return seq_release(inode, file);
+}
+
+static const struct file_operations proc_smack_map_operations = {
+	.open		= proc_smack_map_open,
+	.write		= proc_smack_map_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= proc_smack_map_release,
+};
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
 				struct pid *pid, struct task_struct *task)
 {
@@ -2637,6 +2688,9 @@ static const struct pid_entry tgid_base_stuff[] = {
 	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
 	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
 #endif
+#ifdef CONFIG_SECURITY_SMACK_NS
+	REG("smack_map",    S_IRUGO|S_IWUSR, proc_smack_map_operations),
+#endif
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	REG("timers",	  S_IRUGO, proc_timers_operations),
 #endif
@@ -2982,6 +3036,9 @@ static const struct pid_entry tid_base_stuff[] = {
 	REG("projid_map", S_IRUGO|S_IWUSR, proc_projid_map_operations),
 	REG("setgroups",  S_IRUGO|S_IWUSR, proc_setgroups_operations),
 #endif
+#ifdef CONFIG_SECURITY_SMACK_NS
+	REG("smack_map",    S_IRUGO|S_IWUSR, proc_smack_map_operations),
+#endif
 };
 
 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index a9400cc..a8941a5 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -76,6 +76,11 @@ extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t,
 extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
 extern int proc_setgroups_show(struct seq_file *m, void *v);
 extern bool userns_may_setgroups(const struct user_namespace *ns);
+#ifdef CONFIG_SECURITY_SMACK_NS
+extern const struct seq_operations proc_smack_map_seq_operations;
+ssize_t proc_smack_map_write(struct file *file, const char __user *buf,
+			     size_t size, loff_t *ppos);
+#endif /* CONFIG_SECURITY_SMACK_NS */
 #else
 
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
diff --git a/security/smack/Kconfig b/security/smack/Kconfig
index 271adae..b19a7fb 100644
--- a/security/smack/Kconfig
+++ b/security/smack/Kconfig
@@ -40,3 +40,13 @@ config SECURITY_SMACK_NETFILTER
 	  This enables security marking of network packets using
 	  Smack labels.
 	  If you are unsure how to answer this question, answer N.
+
+config SECURITY_SMACK_NS
+	bool "Smack namespace"
+	depends on SECURITY_SMACK
+	depends on USER_NS
+	help
+	  This enables Smack namespace that makes it possible to map
+	  specific labels within user namespace (analogously to mapping
+	  UIDs) and to gain MAC capabilities over them.
+	  If you are unsure how to answer this question, answer N.
diff --git a/security/smack/Makefile b/security/smack/Makefile
index ee2ebd5..5faebd7 100644
--- a/security/smack/Makefile
+++ b/security/smack/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_SECURITY_SMACK) := smack.o
 
 smack-y := smack_lsm.o smack_access.o smackfs.o
 smack-$(CONFIG_SECURITY_SMACK_NETFILTER) += smack_netfilter.o
+smack-$(CONFIG_SECURITY_SMACK_NS) += smack_ns.o
diff --git a/security/smack/smack.h b/security/smack/smack.h
index 3818d19..a53623a 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -21,6 +21,7 @@
 #include <linux/list.h>
 #include <linux/rculist.h>
 #include <linux/lsm_audit.h>
+#include <linux/user_namespace.h>
 
 /*
  * Smack labels were limited to 23 characters for a long time.
@@ -59,8 +60,36 @@ struct smack_known {
 	struct netlbl_lsm_secattr	smk_netlabel;	/* on wire labels */
 	struct list_head		smk_rules;	/* access rules */
 	struct mutex			smk_rules_lock;	/* lock for rules */
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct list_head		smk_mapped;	/* namespaced labels */
+	struct mutex			smk_mapped_lock;
+#endif /* CONFIG_SECURITY_SMACK_NS */
 };
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+
+/*
+ * User namespace security pointer content.
+ */
+struct smack_ns {
+	struct list_head		smk_mapped;	/* namespaced labels */
+	struct mutex			smk_mapped_lock;
+};
+
+/*
+ * A single entry for a namespaced/mapped label.
+ */
+struct smack_known_ns {
+	struct list_head	smk_list_known;
+	struct list_head	smk_list_ns;
+	struct user_namespace	*smk_ns;
+	char			*smk_mapped;
+	struct smack_known	*smk_unmapped;
+	bool			smk_allocated;
+};
+
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 /*
  * Maximum number of bytes for the levels in a CIPSO IP option.
  * Why 23? CIPSO is constrained to 30, so a 32 byte buffer is
@@ -245,7 +274,7 @@ int smk_tskacc(struct task_struct *, struct smack_known *,
 	       u32, struct smk_audit_info *);
 int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 struct smack_known *smack_from_secid(const u32);
-char *smk_parse_smack(const char *string, int len);
+char *smk_parse_smack(const char *string, int len, bool *allocated);
 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 struct smack_known *smk_import_entry(const char *, int);
 void smk_insert_entry(struct smack_known *skp);
@@ -254,6 +283,17 @@ char *smk_find_label_name(struct smack_known *skp);
 struct smack_known *smk_get_label(const char *string, int len, bool import);
 
 /*
+ * These functions are in smack_ns.c
+ */
+#ifdef CONFIG_SECURITY_SMACK_NS
+struct user_namespace *smk_find_mapped_ns(struct user_namespace *ns);
+struct smack_known_ns *smk_find_mapped(struct smack_known *skp,
+				       struct user_namespace *ns);
+struct smack_known *smk_find_unmapped(const char *string, int len,
+				      struct user_namespace *ns);
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
+/*
  * Shared data.
  */
 extern int smack_enabled;
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 47a9c92..c4d90d2 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -452,13 +452,16 @@ struct smack_known *smk_find_entry(const char *string)
 /**
  * smk_parse_smack - parse smack label from a text string
  * @string: a text string that might contain a Smack label
- * @len: the maximum size, or zero if it is NULL terminated.
+ * @len: the maximum size, or zero if it is NULL terminated
+ * @allocated: (out) indicates whether the return string has been
+ *             allocated and has to be freed with kfree() later
+ *             (built-in labels returned are not allocated)
  *
  * Returns a pointer to the clean label or an error code.
  */
-char *smk_parse_smack(const char *string, int len)
+char *smk_parse_smack(const char *string, int len, bool *allocated)
 {
-	char *smack;
+	char *smack = NULL;
 	int i;
 
 	if (len <= 0)
@@ -480,11 +483,33 @@ char *smk_parse_smack(const char *string, int len)
 	if (i == 0 || i >= SMK_LONGLABEL)
 		return ERR_PTR(-EINVAL);
 
+	/*
+	 * Look for special labels. This way we guarantee that we can compare
+	 * special labels in mapped entries by ==, without strcmp().
+	 */
+	if (len == 1 && !strcmp(string, smack_known_huh.smk_known))
+		smack = smack_known_huh.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_hat.smk_known))
+		smack = smack_known_hat.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_star.smk_known))
+		smack = smack_known_star.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_floor.smk_known))
+		smack = smack_known_floor.smk_known;
+	else if (len == 1 && !strcmp(string, smack_known_web.smk_known))
+		smack = smack_known_web.smk_known;
+
+	if (smack) {
+		*allocated = false;
+
+		return smack;
+	}
+
 	smack = kzalloc(i + 1, GFP_KERNEL);
 	if (smack == NULL)
 		return ERR_PTR(-ENOMEM);
 
 	strncpy(smack, string, i);
+	*allocated = true;
 
 	return smack;
 }
@@ -540,8 +565,9 @@ struct smack_known *smk_import_entry(const char *string, int len)
 	char *smack;
 	int slen;
 	int rc;
+	bool allocated;
 
-	smack = smk_parse_smack(string, len);
+	smack = smk_parse_smack(string, len, &allocated);
 	if (IS_ERR(smack))
 		return ERR_CAST(smack);
 
@@ -577,6 +603,10 @@ struct smack_known *smk_import_entry(const char *string, int len)
 	if (rc >= 0) {
 		INIT_LIST_HEAD(&skp->smk_rules);
 		mutex_init(&skp->smk_rules_lock);
+#ifdef CONFIG_SECURITY_SMACK_NS
+		INIT_LIST_HEAD(&skp->smk_mapped);
+		mutex_init(&skp->smk_mapped_lock);
+#endif /* CONFIG_SECURITY_SMACK_NS */
 		/*
 		 * Make sure that the entry is actually
 		 * filled before putting it on the list.
@@ -590,7 +620,8 @@ struct smack_known *smk_import_entry(const char *string, int len)
 	kfree(skp);
 	skp = ERR_PTR(rc);
 freeout:
-	kfree(smack);
+	if (allocated)
+		kfree(smack);
 unlockout:
 	mutex_unlock(&smack_known_lock);
 
@@ -649,16 +680,19 @@ char *smk_find_label_name(struct smack_known *skp)
 struct smack_known *smk_get_label(const char *string, int len, bool import)
 {
 	struct smack_known *skp;
+	bool allocated;
 	char *cp;
 
 	if (import) {
 		skp = smk_import_entry(string, len);
 	} else {
-		cp = smk_parse_smack(string, len);
+		cp = smk_parse_smack(string, len, &allocated);
 		if (IS_ERR(cp))
 			return ERR_CAST(cp);
 
 		skp = smk_find_entry(cp);
+		if (allocated)
+			kfree(cp);
 	}
 
 	return skp;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index bb74ca9..4ae9a9a 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -41,6 +41,7 @@
 #include <linux/msg.h>
 #include <linux/shm.h>
 #include <linux/binfmts.h>
+#include <linux/user_namespace.h>
 #include "smack.h"
 
 #define TRANS_TRUE	"TRUE"
@@ -4165,6 +4166,53 @@ static void smack_audit_rule_free(void *vrule)
 
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+
+static inline int smack_userns_create(struct user_namespace *ns)
+{
+	struct smack_ns *snsp;
+
+	snsp = kzalloc(sizeof(*snsp), GFP_KERNEL);
+	if (snsp == NULL)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&snsp->smk_mapped);
+	mutex_init(&snsp->smk_mapped_lock);
+
+	ns->security = snsp;
+	return 0;
+}
+
+static inline void smack_userns_free(struct user_namespace *ns)
+{
+	struct smack_ns *snsp = ns->security;
+	struct smack_known *skp;
+	struct smack_known_ns *sknp, *n;
+
+	list_for_each_entry_safe(sknp, n, &snsp->smk_mapped, smk_list_ns) {
+		skp = sknp->smk_unmapped;
+
+		mutex_lock(&skp->smk_mapped_lock);
+		list_del_rcu(&sknp->smk_list_known);
+		if (sknp->smk_allocated)
+			kfree(sknp->smk_mapped);
+		kfree(sknp);
+		mutex_unlock(&skp->smk_mapped_lock);
+
+		list_del(&sknp->smk_list_ns);
+	}
+
+	kfree(snsp);
+}
+
+static inline int smack_userns_setns(struct nsproxy *nsproxy,
+				     struct user_namespace *ns)
+{
+	return 0;
+}
+
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 /**
  * smack_ismaclabel - check if xattr @name references a smack MAC label
  * @name: Full xattr name to check.
@@ -4376,6 +4424,13 @@ struct security_hook_list smack_hooks[] = {
 	LSM_HOOK_INIT(audit_rule_free, smack_audit_rule_free),
 #endif /* CONFIG_AUDIT */
 
+ /* Namespace hooks */
+#ifdef CONFIG_SECURITY_SMACK_NS
+	LSM_HOOK_INIT(userns_create, smack_userns_create),
+	LSM_HOOK_INIT(userns_free, smack_userns_free),
+	LSM_HOOK_INIT(userns_setns, smack_userns_setns),
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 	LSM_HOOK_INIT(ismaclabel, smack_ismaclabel),
 	LSM_HOOK_INIT(secid_to_secctx, smack_secid_to_secctx),
 	LSM_HOOK_INIT(secctx_to_secid, smack_secctx_to_secid),
@@ -4388,6 +4443,27 @@ struct security_hook_list smack_hooks[] = {
 
 static __init void init_smack_known_list(void)
 {
+#ifdef CONFIG_SECURITY_SMACK_NS
+	/*
+	 * Initialize mapped list locks
+	 */
+	mutex_init(&smack_known_huh.smk_mapped_lock);
+	mutex_init(&smack_known_hat.smk_mapped_lock);
+	mutex_init(&smack_known_floor.smk_mapped_lock);
+	mutex_init(&smack_known_star.smk_mapped_lock);
+	mutex_init(&smack_known_invalid.smk_mapped_lock);
+	mutex_init(&smack_known_web.smk_mapped_lock);
+	/*
+	 * Initialize mapped lists
+	 */
+	INIT_LIST_HEAD(&smack_known_huh.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_hat.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_star.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_floor.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_invalid.smk_mapped);
+	INIT_LIST_HEAD(&smack_known_web.smk_mapped);
+#endif /* CONFIG_SECURITY_SMACK_NS */
+
 	/*
 	 * Initialize rule list locks
 	 */
diff --git a/security/smack/smack_ns.c b/security/smack/smack_ns.c
new file mode 100644
index 0000000..141a836
--- /dev/null
+++ b/security/smack/smack_ns.c
@@ -0,0 +1,432 @@
+/*
+ * Copyright (C) 2014 Samsung Electronics.
+ *
+ * Smack namespaces
+ *
+ * Author(s):
+ *    Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
+ *
+ * This program is free software, you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/file.h>
+#include <linux/ctype.h>
+#include <linux/rculist.h>
+#include <linux/seq_file.h>
+#include <linux/user_namespace.h>
+#include "smack.h"
+
+/**
+ * smk_find_mapped_ns - Finds a first namespace from this one through
+ * its parrents that has a map. This map is the effective map in this
+ * namespace.
+ * @ns: a user namespace for which we search for a mapped ns
+ *
+ * Returns a namespace that has a non-NULL map, or NULL if there is
+ * no mapped namespace.
+ *
+ * Can be effectively used to answer a question: "is there a Smack
+ * map for this namespace?"
+ */
+struct user_namespace *smk_find_mapped_ns(struct user_namespace *ns)
+{
+	struct user_namespace *user_ns = ns;
+
+	do {
+		struct smack_ns *sns = user_ns->security;
+
+		if (sns && !list_empty(&sns->smk_mapped))
+			break;
+
+		user_ns = user_ns->parent;
+	} while (user_ns);
+
+	return user_ns;
+}
+
+/**
+ * __smk_find_mapped - an internal version of smk_find_mapped
+ *                     that doesn't use smk_find_mapped_ns, but
+ *                     operates directly on the passed one.
+ */
+static struct smack_known_ns *__smk_find_mapped(struct smack_known *skp,
+						struct user_namespace *ns)
+{
+	struct smack_known_ns *sknp;
+
+	if (ns == NULL)
+		return NULL;
+
+	list_for_each_entry_rcu(sknp, &skp->smk_mapped, smk_list_known)
+		if (sknp->smk_ns == ns)
+			return sknp;
+
+	return NULL;
+}
+
+/**
+ * smk_find_mapped - Finds a mapped label on the smack_known's mapped list
+ * @skp: a label which mapped label we look for
+ * @ns: a user namespace the label we search for is assigned to
+ *
+ * Returns a pointer to the mapped label if one exists that is
+ * assigned to the specified user namespace or NULL if not found.
+ */
+struct smack_known_ns *smk_find_mapped(struct smack_known *skp,
+				       struct user_namespace *ns)
+{
+	struct user_namespace *user_ns = smk_find_mapped_ns(ns);
+
+	return __smk_find_mapped(skp, user_ns);
+}
+
+/**
+ * __smk_find_unmapped - an internal version of smk_find_unmapped
+ *                       that doesn't use smk_find_mapped_ns, but
+ *                       operates directly on the passed one.
+ */
+static struct smack_known *__smk_find_unmapped(const char *string, int len,
+					       struct user_namespace *ns)
+{
+	struct smack_ns *snsp;
+	struct smack_known *skp = NULL;
+	struct smack_known_ns *sknp;
+	char *smack;
+	bool allocated = false;
+
+	if (ns == NULL)
+		return NULL;
+
+	snsp = ns->security;
+
+	smack = smk_parse_smack(string, len, &allocated);
+	if (IS_ERR(smack))
+		return ERR_CAST(smack);
+
+	list_for_each_entry_rcu(sknp, &snsp->smk_mapped, smk_list_ns) {
+		if (strcmp(smack, sknp->smk_mapped) == 0) {
+			skp = sknp->smk_unmapped;
+			break;
+		}
+	}
+
+	if (allocated)
+		kfree(smack);
+	return skp;
+}
+
+/**
+ * smk_find_unmapped - Finds an original label by a mapped label string
+ *                     and the namespace it could be mapped in
+ * @string: a name of a mapped label we look for
+ * @len: the string size, or zero if it is NULL terminated.
+ * @ns: a namespace the looked for label should be mapped in
+ *
+ * Returns a smack_known label that is mapped as 'string' in 'ns',
+ * NULL if not found or an error code.
+ */
+struct smack_known *smk_find_unmapped(const char *string, int len,
+				      struct user_namespace *ns)
+{
+	struct user_namespace *user_ns = smk_find_mapped_ns(ns);
+
+	return __smk_find_unmapped(string, len, user_ns);
+}
+
+/**
+ * smk_import_mapped - Imports a mapped label effectively creating a mapping.
+ * @skp: a label we map
+ * @ns: a user namespace this label will be mapped in
+ * @string: a text string of the mapped label
+ * @len: the maximum size, or zero if it is NULL terminanted
+ *
+ * Returns a pointer to the mapped label entry or an error code.
+ *
+ * The mapped label will be added to 2 lists:
+ *   - a list of mapped labels of skp
+ *   - a list of labels mapped in ns
+ */
+static struct smack_known_ns *smk_import_mapped(struct smack_known *skp,
+						struct user_namespace *ns,
+						const char *string, int len)
+{
+	struct smack_ns *snsp = ns->security;
+	struct smack_known_ns *sknp;
+	char *mapped;
+	bool allocated;
+
+	/* Mapping init_user_ns is against the design and pointless */
+	if (ns == &init_user_ns)
+		return ERR_PTR(-EBADR);
+
+	mapped = smk_parse_smack(string, len, &allocated);
+	if (IS_ERR(mapped))
+		return ERR_CAST(mapped);
+
+	mutex_lock(&skp->smk_mapped_lock);
+
+	/*
+	 * Don't allow one<->many mappings in namespace, rename.
+	 * This code won't get triggered for now as trying to assign
+	 * a duplicate is forbidden in proc_smack_map_write().
+	 * Leaving this as this function might be also used elsewhere.
+	 */
+	sknp = smk_find_mapped(skp, ns);
+	if (sknp != NULL) {
+		if (sknp->smk_allocated)
+			kfree(sknp->smk_mapped);
+		sknp->smk_mapped = mapped;
+		sknp->smk_allocated = allocated;
+		goto unlockout;
+	}
+
+	sknp = kzalloc(sizeof(*sknp), GFP_KERNEL);
+	if (sknp == NULL) {
+		sknp = ERR_PTR(-ENOMEM);
+		if (allocated)
+			kfree(mapped);
+		goto unlockout;
+	}
+
+	sknp->smk_ns = ns;
+	sknp->smk_mapped = mapped;
+	sknp->smk_allocated = allocated;
+	sknp->smk_unmapped = skp;
+	list_add_rcu(&sknp->smk_list_known, &skp->smk_mapped);
+
+	mutex_lock(&snsp->smk_mapped_lock);
+	list_add_rcu(&sknp->smk_list_ns, &snsp->smk_mapped);
+	mutex_unlock(&snsp->smk_mapped_lock);
+
+unlockout:
+	mutex_unlock(&skp->smk_mapped_lock);
+
+	return sknp;
+}
+
+static void *proc_smack_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct smack_known *skp;
+	struct user_namespace *ns = seq->private;
+	loff_t counter = *pos;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(skp, &smack_known_list, list)
+		if (smk_find_mapped(skp, ns) && counter-- == 0)
+			return skp;
+
+	return NULL;
+}
+
+static void proc_smack_map_seq_stop(struct seq_file *seq, void *v)
+{
+	rcu_read_unlock();
+}
+
+static void *proc_smack_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct smack_known *skp = v;
+	struct user_namespace *ns = seq->private;
+
+	list_for_each_entry_continue_rcu(skp, &smack_known_list, list) {
+		if (smk_find_mapped(skp, ns)) {
+			(*pos)++;
+			return skp;
+		}
+	}
+
+	return NULL;
+}
+
+static int proc_smack_map_seq_show(struct seq_file *seq, void *v)
+{
+	struct smack_known *skp = v;
+	struct user_namespace *ns = seq->private;
+	struct smack_known_ns *sknp;
+
+	/*
+	 * QUESTION: linux-api
+	 * What to print when in init_map_ns where the map is empty
+	 * effectively meaning identity? Unfortunately it's impossible
+	 * to show identity in this syntax without printing all the labels.
+	 */
+	if (smk_find_mapped_ns(ns) == NULL) {
+		seq_puts("This namespace is not mapped.\n");
+	} else {
+		sknp = smk_find_mapped(skp, ns);
+		if (sknp)
+			seq_printf(seq, "%s -> %s\n",
+				   skp->smk_known, sknp->smk_mapped);
+	}
+
+	return 0;
+}
+
+const struct seq_operations proc_smack_map_seq_operations = {
+	.start = proc_smack_map_seq_start,
+	.stop = proc_smack_map_seq_stop,
+	.next = proc_smack_map_seq_next,
+	.show = proc_smack_map_seq_show,
+};
+
+static DEFINE_MUTEX(smk_map_mutex);
+
+static bool mapping_permitted(const struct file *file,
+			      struct user_namespace *user_ns)
+{
+	/*
+	 * Do not allow mapping own label. This is in contrast to user
+	 * namespace where you can always map your own UID. In Smack having
+	 * administrative privileges over your own label (which Smack
+	 * namespace effectively gives you) is not equivalent to user
+	 * namespace. E.g. things like setting exec/transmute labels that
+	 * otherwise would be denied. Hence no own_label param here.
+	 */
+
+	/*
+	 * Adjusting namespace settings requires capabilities on the target.
+	 */
+	if (!file_ns_capable(file, user_ns, CAP_MAC_ADMIN))
+		return false;
+
+	/*
+	 * And it requires capabilities in the parent.
+	 *
+	 * If the Smack namespace was properly hierarchical the user_ns to
+	 * check against could be 'user_ns->parent'. Right now because of
+	 * security concerns only privileged initial namespace is allowed
+	 * to fill the map. For a hierarchical namespaces one would
+	 * implement mapping (in the child namespaces) of only mapped labels
+	 * (in parent namespace) and change '&init_user_ns' to
+	 * 'user_ns->parent'. This will be added in the future.
+	 */
+	if (smack_ns_privileged(&init_user_ns, CAP_MAC_ADMIN) &&
+	    file_ns_capable(file, &init_user_ns, CAP_MAC_ADMIN))
+		return true;
+
+	return false;
+}
+
+ssize_t proc_smack_map_write(struct file *file, const char __user *buf,
+			     size_t size, loff_t *ppos)
+{
+	struct seq_file *seq = file->private_data;
+	struct user_namespace *ns = seq->private;
+	struct user_namespace *seq_ns = seq_user_ns(seq);
+	struct smack_known *skp;
+	struct smack_known_ns *sknp;
+	unsigned long page = 0;
+	char *kbuf, *pos, *next_line, *tok[2];
+	ssize_t ret;
+	int i;
+
+	/* Mapping labels for the init ns makes no sense */
+	if (ns == &init_user_ns)
+		return -EBADR;
+
+	if ((seq_ns != ns) && (seq_ns != ns->parent))
+		return -EPERM;
+
+	mutex_lock(&smk_map_mutex);
+
+	ret = -EPERM;
+	if (!mapping_permitted(file, ns))
+		goto out;
+
+	/* Get a buffer */
+	ret = ENOMEM;
+	page = __get_free_page(GFP_TEMPORARY);
+	if (!page)
+		goto out;
+	kbuf = (char *)page;
+
+	/* Only allow <= page size writes at the beginning of the file */
+	ret = -EINVAL;
+	if ((*ppos != 0) || (size >= PAGE_SIZE))
+		goto out;
+
+	/* Slurp in the user data */
+	ret = -EFAULT;
+	if (copy_from_user(kbuf, buf, size))
+		goto out;
+	kbuf[size] = '\0';
+
+	/* Parse the user data */
+	pos = kbuf;
+
+	for (; pos; pos = next_line) {
+		ret = -EINVAL;
+
+		/* Find the end of line and ensure I don't look past it */
+		next_line = strchr(pos, '\n');
+		if (next_line) {
+			*next_line = '\0';
+			next_line++;
+			if (*next_line == '\0')
+				next_line = NULL;
+		}
+
+		/* Find tokens in line */
+		for (i = 0; i < 2; ++i) {
+			while (isspace(*pos))
+				*(pos++) = '\0';
+
+			/* unexpected end of file */
+			if (*pos == '\0')
+				goto out;
+
+			tok[i] = pos;
+
+			/* find the end of the token */
+			while (*pos != '\0' && !isspace(*pos))
+				++pos;
+		}
+
+		/* NUL terminate the last token if not EOL */
+		while (isspace(*pos))
+			*(pos++) = '\0';
+
+		/* there should not be any trailing data */
+		if (*pos != '\0')
+			goto out;
+
+		/* do not allow to map 2 different labels to one name */
+		skp = __smk_find_unmapped(tok[1], 0, ns);
+		if (IS_ERR(skp)) {
+			ret = PTR_ERR(skp);
+			goto out;
+		}
+		if (skp != NULL) {
+			ret = -EEXIST;
+			goto out;
+		}
+
+		skp = smk_import_entry(tok[0], 0);
+		if (IS_ERR(skp)) {
+			ret = PTR_ERR(skp);
+			goto out;
+		}
+
+		/* do not allow remapping */
+		ret = -EEXIST;
+		if (__smk_find_mapped(skp, ns))
+			goto out;
+
+		sknp = smk_import_mapped(skp, ns, tok[1], 0);
+		if (IS_ERR(sknp)) {
+			ret = PTR_ERR(sknp);
+			goto out;
+		}
+	}
+
+	ret = size;
+
+out:
+	mutex_unlock(&smk_map_mutex);
+	if (page)
+		free_page(page);
+
+	return ret;
+}
-- 
2.1.0

[PATCH v2 6/7] smack: namespace implementation

[Lukasz Pawelczyk]

This commit uses all the changes introduced in "namespace groundwork"
and previous preparation patches and makes smack aware of its namespace
and mapped labels.

It modifies the following functions to be namespace aware:
- smk_access
- smk_find_label_name
- smk_get_label

And all functions that use them (e.g. smk_tskacc).

It also adds another function that is used throughout Smack LSM hooks:
- smk_labels_valid - it checks whether both, subject and object labels
  are properly mapped in a namespace where they are to be used. This
  function is used mostly together with a capability check when there is
  no proper access check that usually checks for that.

All the Smack LSM hooks have been adapted to be namespace aware.

The capabilities (CAP_MAC_ADMIN, CAP_MAC_OVERRIDE) has been allowed in
the namespace for few cases. Check the documentation for the details.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 security/smack/smack.h        |  61 ++++++-
 security/smack/smack_access.c |  99 ++++++++++--
 security/smack/smack_lsm.c    | 358 ++++++++++++++++++++++++++++++------------
 security/smack/smack_ns.c     |  41 ++++-
 security/smack/smackfs.c      |  57 ++++---
 5 files changed, 474 insertions(+), 142 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index a53623a..b8ed852 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -104,6 +104,7 @@ struct superblock_smack {
 	struct smack_known	*smk_floor;
 	struct smack_known	*smk_hat;
 	struct smack_known	*smk_default;
+	struct user_namespace	*smk_ns;
 	int			smk_initialized;
 };
 
@@ -111,6 +112,7 @@ struct socket_smack {
 	struct smack_known	*smk_out;	/* outbound label */
 	struct smack_known	*smk_in;	/* inbound label */
 	struct smack_known	*smk_packet;	/* TCP peer label */
+	struct user_namespace	*smk_ns;	/* user namespace */
 };
 
 /*
@@ -131,6 +133,14 @@ struct task_smack {
 	struct mutex		smk_rules_lock;	/* lock for the rules */
 };
 
+/*
+ * Used for IPC objects (sem, shm, etc)
+ */
+struct ipc_smack {
+	struct smack_known	*smk_known;	/* label for access control */
+	struct user_namespace	*smk_ns;	/* user namespace */
+};
+
 #define	SMK_INODE_INSTANT	0x01	/* inode is instantiated */
 #define	SMK_INODE_TRANSMUTE	0x02	/* directory is transmuting */
 #define	SMK_INODE_CHANGED	0x04	/* smack was transmuted */
@@ -269,18 +279,20 @@ struct inode_smack *new_inode_smack(struct smack_known *);
  */
 int smk_access_entry(char *, char *, struct list_head *);
 int smk_access(struct smack_known *, struct smack_known *,
-	       int, struct smk_audit_info *);
+	       struct user_namespace *, int, struct smk_audit_info *);
 int smk_tskacc(struct task_struct *, struct smack_known *,
+	       struct user_namespace *, u32, struct smk_audit_info *);
+int smk_curacc(struct smack_known *, struct user_namespace *,
 	       u32, struct smk_audit_info *);
-int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
 struct smack_known *smack_from_secid(const u32);
 char *smk_parse_smack(const char *string, int len, bool *allocated);
 int smk_netlbl_mls(int, char *, struct netlbl_lsm_secattr *, int);
 struct smack_known *smk_import_entry(const char *, int);
 void smk_insert_entry(struct smack_known *skp);
 struct smack_known *smk_find_entry(const char *);
-char *smk_find_label_name(struct smack_known *skp);
-struct smack_known *smk_get_label(const char *string, int len, bool import);
+char *smk_find_label_name(struct smack_known *skp, struct user_namespace *ns);
+struct smack_known *smk_get_label(const char *string, int len, bool import,
+				  struct user_namespace *ns);
 
 /*
  * These functions are in smack_ns.c
@@ -291,6 +303,15 @@ struct smack_known_ns *smk_find_mapped(struct smack_known *skp,
 				       struct user_namespace *ns);
 struct smack_known *smk_find_unmapped(const char *string, int len,
 				      struct user_namespace *ns);
+bool smk_labels_valid(struct smack_known *sbj, struct smack_known *obj,
+		      struct user_namespace *ns);
+#else
+static inline bool smk_labels_valid(struct smack_known *sbj,
+				    struct smack_known *obj,
+				    struct user_namespace *ns)
+{
+	return true;
+}
 #endif /* CONFIG_SECURITY_SMACK_NS */
 
 /*
@@ -397,18 +418,48 @@ static inline struct smack_known *smk_of_current(void)
 }
 
 /*
+ * Present a pointer to the user namespace entry in an task blob.
+ */
+static inline
+struct user_namespace *ns_of_task_struct(const struct task_struct *t)
+{
+	struct user_namespace *ns;
+
+	rcu_read_lock();
+	ns = __task_cred(t)->user_ns;
+	rcu_read_unlock();
+
+	return ns;
+}
+
+/*
+ * Present a pointer to the user namespace entry in the current task blob.
+ */
+static inline struct user_namespace *ns_of_current(void)
+{
+	return current->cred->user_ns;
+}
+
+/*
  * Internal smack capability check complimentary to the
  * set of kernel capable() and has_capability() functions
  *
  * For a capability in smack related checks to be effective it needs to:
  * - have empty onlycap or the current label be the same as onlycap
- * - be in the initial user ns
+ * - be in the initial user ns or have a filled map in the child ns
  */
 static inline int smack_capability_allowed(struct smack_known *skp,
 					   struct user_namespace *user_ns)
 {
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct smack_ns *sns = user_ns->security;
+
+	if (user_ns != &init_user_ns && list_empty(&sns->smk_mapped))
+		return 0;
+#else
 	if (user_ns != &init_user_ns)
 		return 0;
+#endif /* CONFIG_SECURITY_SMACK_NS */
 
 	if (smack_onlycap != NULL && smack_onlycap != skp)
 		return 0;
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index c4d90d2..600e95c 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
+#include <linux/user_namespace.h>
 #include "smack.h"
 
 struct smack_known smack_known_huh = {
@@ -113,6 +114,7 @@ int smk_access_entry(char *subject_label, char *object_label,
  * smk_access - determine if a subject has a specific access to an object
  * @subject: a pointer to the subject's Smack label entry
  * @object: a pointer to the object's Smack label entry
+ * @ns: user namespace to check against (usually subject's)
  * @request: the access requested, in "MAY" format
  * @a : a pointer to the audit data
  *
@@ -123,10 +125,34 @@ int smk_access_entry(char *subject_label, char *object_label,
  * Smack labels are shared on smack_list
  */
 int smk_access(struct smack_known *subject, struct smack_known *object,
-	       int request, struct smk_audit_info *a)
+	       struct user_namespace *ns, int request, struct smk_audit_info *a)
 {
 	int may = MAY_NOT;
 	int rc = 0;
+	char *subject_label = subject->smk_known;
+	char *object_label = object->smk_known;
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct smack_known_ns *sknp;
+	struct smack_known_ns *oknp;
+
+	/*
+	 * For the namespaced case we need to check whether the labels
+	 * are mapped. If not, refuse. If yes check the builtin rules
+	 * on the mapped label strings so the builtin labels can
+	 * work properly inside the namespace.
+	 */
+	if (smk_find_mapped_ns(ns)) {
+		sknp = smk_find_mapped(subject, ns);
+		oknp = smk_find_mapped(object, ns);
+		if (!sknp || !oknp) {
+			rc = -EACCES;
+			goto out_audit;
+		}
+
+		subject_label = sknp->smk_mapped;
+		object_label = oknp->smk_mapped;
+	}
+#endif
 
 	/*
 	 * Hardcoded comparisons.
@@ -134,7 +160,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	/*
 	 * A star subject can't access any object.
 	 */
-	if (subject == &smack_known_star) {
+	if (subject_label == smack_known_star.smk_known) {
 		rc = -EACCES;
 		goto out_audit;
 	}
@@ -143,18 +169,19 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	 * Tasks cannot be assigned the internet label.
 	 * An internet subject can access any object.
 	 */
-	if (object == &smack_known_web || subject == &smack_known_web)
+	if (object_label == smack_known_web.smk_known ||
+	    subject_label == smack_known_web.smk_known)
 		goto out_audit;
 	/*
 	 * A star object can be accessed by any subject.
 	 */
-	if (object == &smack_known_star)
+	if (object_label == smack_known_star.smk_known)
 		goto out_audit;
 	/*
 	 * An object can be accessed in any way by a subject
 	 * with the same label.
 	 */
-	if (subject->smk_known == object->smk_known)
+	if (subject_label == object_label)
 		goto out_audit;
 	/*
 	 * A hat subject can read or lock any object.
@@ -162,9 +189,9 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	 */
 	if ((request & MAY_ANYREAD) == request ||
 	    (request & MAY_LOCK) == request) {
-		if (object == &smack_known_floor)
+		if (object_label == smack_known_floor.smk_known)
 			goto out_audit;
-		if (subject == &smack_known_hat)
+		if (subject_label == smack_known_hat.smk_known)
 			goto out_audit;
 	}
 
@@ -174,6 +201,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
 	 * access (e.g. read is included in readwrite) it's
 	 * good. A negative response from smk_access_entry()
 	 * indicates there is no entry for this pair.
+	 * For this check we need real, not mapped labels.
 	 */
 	rcu_read_lock();
 	may = smk_access_entry(subject->smk_known, object->smk_known,
@@ -219,6 +247,7 @@ out_audit:
  * smk_tskacc - determine if a task has a specific access to an object
  * @tsp: a pointer to the subject's task
  * @obj_known: a pointer to the object's label entry
+ * @obj_ns: an object's namespace to check the caps against
  * @mode: the access requested, in "MAY" format
  * @a : common audit data
  *
@@ -228,16 +257,18 @@ out_audit:
  * to override the rules.
  */
 int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
-	       u32 mode, struct smk_audit_info *a)
+	       struct user_namespace *obj_ns, u32 mode,
+	       struct smk_audit_info *a)
 {
 	struct smack_known *sbj_known = smk_of_task_struct(task);
+	struct user_namespace *sbj_ns = ns_of_task_struct(task);
 	int may;
 	int rc;
 
 	/*
 	 * Check the global rule list
 	 */
-	rc = smk_access(sbj_known, obj_known, mode, NULL);
+	rc = smk_access(sbj_known, obj_known, sbj_ns, mode, NULL);
 	if (rc >= 0) {
 		struct task_smack *tsp;
 
@@ -261,8 +292,10 @@ int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
 
 	/*
 	 * Allow for priviliged to override policy.
+	 * Either in init_ns or when both labels are mapped.
 	 */
-	if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
+	if (rc != 0 && smk_labels_valid(sbj_known, obj_known, sbj_ns)
+	    && smack_has_ns_privilege(task, obj_ns, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 out_audit:
@@ -277,6 +310,7 @@ out_audit:
 /**
  * smk_curacc - determine if current has a specific access to an object
  * @obj_known: a pointer to the object's Smack label entry
+ * @obj_ns: an object's namespace to check the caps against
  * @mode: the access requested, in "MAY" format
  * @a : common audit data
  *
@@ -285,10 +319,10 @@ out_audit:
  * non zero otherwise. It allows that current may have the capability
  * to override the rules.
  */
-int smk_curacc(struct smack_known *obj_known,
+int smk_curacc(struct smack_known *obj_known, struct user_namespace *obj_ns,
 	       u32 mode, struct smk_audit_info *a)
 {
-	return smk_tskacc(current, obj_known, mode, a);
+	return smk_tskacc(current, obj_known, obj_ns, mode, a);
 }
 
 #ifdef CONFIG_AUDIT
@@ -656,14 +690,32 @@ struct smack_known *smack_from_secid(const u32 secid)
 }
 
 /**
- * smk_find_label_name - A helper to get a string value of a label
+ * smk_find_label_name - A helper to get a string value of either a label or a
+ *                       mapped label when inside a namespace
  * @skp: a label we want a string value from
+ * @ns: namespace against which we want to get the value
  *
  * Returns a pointer to a label name or NULL if label name not found.
  */
-char *smk_find_label_name(struct smack_known *skp)
+char *smk_find_label_name(struct smack_known *skp, struct user_namespace *ns)
 {
-	return skp->smk_known;
+	char *name = NULL;
+
+#ifdef CONFIG_SECURITY_SMACK_NS
+	struct smack_known_ns *sknp;
+
+	if (smk_find_mapped_ns(ns)) {
+		sknp = smk_find_mapped(skp, ns);
+		if (sknp != NULL)
+			name = sknp->smk_mapped;
+	} else {
+		name = skp->smk_known;
+	}
+#else
+	name = skp->smk_known;
+#endif
+
+	return name;
 }
 
 /**
@@ -672,17 +724,32 @@ char *smk_find_label_name(struct smack_known *skp)
  * @string: a name of a label we look for or want to import
  * @len: the string size, or zero if it is NULL terminated
  * @import: whether we should import the label if not found
+ * @ns: a namespace the looked for label should be in
  *
  * Returns a smack_known label that is either imported or found.
  * NULL if label not found (only when import == false).
  * Error code otherwise.
  */
-struct smack_known *smk_get_label(const char *string, int len, bool import)
+struct smack_known *smk_get_label(const char *string, int len, bool import,
+				  struct user_namespace *ns)
 {
 	struct smack_known *skp;
 	bool allocated;
 	char *cp;
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+	if (smk_find_mapped_ns(ns)) {
+		skp = smk_find_unmapped(string, len, ns);
+
+		/* Label not found but we can't import in namespaces */
+		if (skp == NULL && import)
+			skp = ERR_PTR(-EBADR);
+
+		/* will also return error codes from smk_find_unmapped() */
+		return skp;
+	}
+#endif
+
 	if (import) {
 		skp = smk_import_entry(string, len);
 	} else {
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4ae9a9a..af0a5fd 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -373,6 +373,7 @@ static inline unsigned int smk_ptrace_mode(unsigned int mode)
  * smk_ptrace_rule_check - helper for ptrace access
  * @tracer: tracer process
  * @tracee_known: label entry of the process that's about to be traced
+ * @tracee_ns: a tracee's namespace to check the caps against
  * @mode: ptrace attachment mode (PTRACE_MODE_*)
  * @func: name of the function that called us, used for audit
  *
@@ -380,6 +381,7 @@ static inline unsigned int smk_ptrace_mode(unsigned int mode)
  */
 static int smk_ptrace_rule_check(struct task_struct *tracer,
 				 struct smack_known *tracee_known,
+				 struct user_namespace *tracee_ns,
 				 unsigned int mode, const char *func)
 {
 	int rc;
@@ -391,21 +393,28 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 		saip = &ad;
 	}
 
-
 	if ((mode & PTRACE_MODE_ATTACH) &&
 	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
 	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
 		struct smack_known *tracer_known = smk_of_task_struct(tracer);
+		struct user_namespace *tracer_ns = ns_of_task_struct(tracer);
+
+		if (!smk_labels_valid(tracer_known, tracee_known, tracer_ns)) {
+			rc = -EACCES;
+			goto out;
+		}
 
 		if (tracer_known->smk_known == tracee_known->smk_known)
 			rc = 0;
 		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
 			rc = -EACCES;
-		else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
+		else if (smack_has_ns_privilege(tracer, tracee_ns,
+						CAP_SYS_PTRACE))
 			rc = 0;
 		else
 			rc = -EPERM;
 
+out:
 		if (saip)
 			smack_log(tracer_known->smk_known,
 				  tracee_known->smk_known,
@@ -415,7 +424,8 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 	}
 
 	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
-	return smk_tskacc(tracer, tracee_known, smk_ptrace_mode(mode), saip);
+	return smk_tskacc(tracer, tracee_known, tracee_ns,
+			  smk_ptrace_mode(mode), saip);
 }
 
 /*
@@ -435,8 +445,9 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 {
 	struct smack_known *skp = smk_of_task_struct(ctp);
+	struct user_namespace *ns = ns_of_task_struct(ctp);
 
-	return smk_ptrace_rule_check(current, skp, mode, __func__);
+	return smk_ptrace_rule_check(current, skp, ns, mode, __func__);
 }
 
 /**
@@ -450,8 +461,10 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 static int smack_ptrace_traceme(struct task_struct *ptp)
 {
 	struct smack_known *skp = smk_of_current();
+	struct user_namespace *ns = ns_of_current();
 
-	return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
+	return smk_ptrace_rule_check(ptp, skp, ns, PTRACE_MODE_ATTACH,
+				     __func__);
 }
 
 /**
@@ -498,6 +511,7 @@ static int smack_sb_alloc_security(struct super_block *sb)
 	sbsp->smk_default = &smack_known_floor;
 	sbsp->smk_floor = &smack_known_floor;
 	sbsp->smk_hat = &smack_known_hat;
+	sbsp->smk_ns = get_user_ns(&init_user_ns);
 	/*
 	 * smk_initialized will be zero from kzalloc.
 	 */
@@ -513,6 +527,9 @@ static int smack_sb_alloc_security(struct super_block *sb)
  */
 static void smack_sb_free_security(struct super_block *sb)
 {
+	struct superblock_smack *sbsp = sb->s_security;
+
+	put_user_ns(sbsp->smk_ns);
 	kfree(sb->s_security);
 	sb->s_security = NULL;
 }
@@ -579,6 +596,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 	struct superblock_smack *sp = sb->s_security;
 	struct inode_smack *isp;
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	char *op;
 	char *commap;
 	int transmute = 0;
@@ -596,7 +614,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		if (strncmp(op, SMK_FSHAT, strlen(SMK_FSHAT)) == 0) {
 			op += strlen(SMK_FSHAT);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_hat = skp;
@@ -604,7 +622,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSFLOOR, strlen(SMK_FSFLOOR)) == 0) {
 			op += strlen(SMK_FSFLOOR);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_floor = skp;
@@ -613,7 +631,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		} else if (strncmp(op, SMK_FSDEFAULT,
 				   strlen(SMK_FSDEFAULT)) == 0) {
 			op += strlen(SMK_FSDEFAULT);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_default = skp;
@@ -621,7 +639,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSROOT, strlen(SMK_FSROOT)) == 0) {
 			op += strlen(SMK_FSROOT);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -629,7 +647,7 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 
 		} else if (strncmp(op, SMK_FSTRANS, strlen(SMK_FSTRANS)) == 0) {
 			op += strlen(SMK_FSTRANS);
-			skp = smk_get_label(op, 0, true);
+			skp = smk_get_label(op, 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -638,7 +656,12 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		}
 	}
 
-	if (!smack_privileged(CAP_MAC_ADMIN)) {
+	/*
+	 * Check for non-privileged case. If current is inside the namespace
+	 * and the it has privileges the validity of labels has already been
+	 * checked during smk_get_label()
+	 */
+	if (!smack_ns_privileged(ns, CAP_MAC_ADMIN)) {
 		/*
 		 * Unprivileged mounts don't get to specify Smack values.
 		 */
@@ -651,6 +674,13 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 		sp->smk_root = skp;
 		sp->smk_default = skp;
 	}
+
+	/*
+	 * Set the superblock namespace from a mounting process
+	 */
+	put_user_ns(sp->smk_ns);
+	sp->smk_ns = get_user_ns(ns);
+
 	/*
 	 * Initialize the root inode.
 	 */
@@ -685,7 +715,7 @@ static int smack_sb_statfs(struct dentry *dentry)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(sbp->smk_floor, MAY_READ, &ad);
+	rc = smk_curacc(sbp->smk_floor, sbp->smk_ns, MAY_READ, &ad);
 	rc = smk_bu_current("statfs", sbp->smk_floor, MAY_READ, rc);
 	return rc;
 }
@@ -705,6 +735,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	struct inode *inode = file_inode(bprm->file);
 	struct task_smack *bsp = bprm->cred->security;
 	struct inode_smack *isp;
+	struct user_namespace *ns = ns_of_current();
 	int rc;
 
 	if (bprm->cred_prepared)
@@ -714,6 +745,13 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
 		return 0;
 
+#ifdef CONFIG_SECURITY_SMACK_NS
+	/* one label version of smk_labels_valid() */
+	if (smk_find_mapped_ns(ns) &&
+	    smk_find_mapped(isp->smk_task, ns) == NULL)
+		return -EACCES;
+#endif
+
 	if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
 		struct task_struct *tracer;
 		rc = 0;
@@ -721,9 +759,8 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 		rcu_read_lock();
 		tracer = ptrace_parent(current);
 		if (likely(tracer != NULL))
-			rc = smk_ptrace_rule_check(tracer,
-						   isp->smk_task,
-						   PTRACE_MODE_ATTACH,
+			rc = smk_ptrace_rule_check(tracer, isp->smk_task,
+						   ns, PTRACE_MODE_ATTACH,
 						   __func__);
 		rcu_read_unlock();
 
@@ -864,6 +901,7 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 			    struct dentry *new_dentry)
 {
 	struct smack_known *isp;
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -871,13 +909,13 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
 
 	isp = smk_of_inode(d_backing_inode(old_dentry));
-	rc = smk_curacc(isp, MAY_WRITE, &ad);
+	rc = smk_curacc(isp, ns, MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_WRITE, rc);
 
 	if (rc == 0 && d_is_positive(new_dentry)) {
 		isp = smk_of_inode(d_backing_inode(new_dentry));
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
-		rc = smk_curacc(isp, MAY_WRITE, &ad);
+		rc = smk_curacc(isp, ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_WRITE, rc);
 	}
 
@@ -895,6 +933,7 @@ static int smack_inode_link(struct dentry *old_dentry, struct inode *dir,
 static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 {
 	struct inode *ip = d_backing_inode(dentry);
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -904,7 +943,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 	/*
 	 * You need write access to the thing you're unlinking
 	 */
-	rc = smk_curacc(smk_of_inode(ip), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(ip), ns, MAY_WRITE, &ad);
 	rc = smk_bu_inode(ip, MAY_WRITE, rc);
 	if (rc == 0) {
 		/*
@@ -912,7 +951,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
 		 */
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 		smk_ad_setfield_u_fs_inode(&ad, dir);
-		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(dir), ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
 	}
 	return rc;
@@ -928,6 +967,7 @@ static int smack_inode_unlink(struct inode *dir, struct dentry *dentry)
  */
 static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -937,7 +977,8 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 	/*
 	 * You need write access to the thing you're removing
 	 */
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), ns,
+			MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	if (rc == 0) {
 		/*
@@ -945,7 +986,7 @@ static int smack_inode_rmdir(struct inode *dir, struct dentry *dentry)
 		 */
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 		smk_ad_setfield_u_fs_inode(&ad, dir);
-		rc = smk_curacc(smk_of_inode(dir), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(dir), ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(dir, MAY_WRITE, rc);
 	}
 
@@ -969,21 +1010,22 @@ static int smack_inode_rename(struct inode *old_inode,
 			      struct inode *new_inode,
 			      struct dentry *new_dentry)
 {
-	int rc;
 	struct smack_known *isp;
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
+	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, old_dentry);
 
 	isp = smk_of_inode(d_backing_inode(old_dentry));
-	rc = smk_curacc(isp, MAY_READWRITE, &ad);
+	rc = smk_curacc(isp, ns, MAY_READWRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(old_dentry), MAY_READWRITE, rc);
 
 	if (rc == 0 && d_is_positive(new_dentry)) {
 		isp = smk_of_inode(d_backing_inode(new_dentry));
 		smk_ad_setfield_u_fs_path_dentry(&ad, new_dentry);
-		rc = smk_curacc(isp, MAY_READWRITE, &ad);
+		rc = smk_curacc(isp, ns, MAY_READWRITE, &ad);
 		rc = smk_bu_inode(d_backing_inode(new_dentry), MAY_READWRITE, rc);
 	}
 	return rc;
@@ -1000,6 +1042,7 @@ static int smack_inode_rename(struct inode *old_inode,
  */
 static int smack_inode_permission(struct inode *inode, int mask)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int no_block = mask & MAY_NOT_BLOCK;
 	int rc;
@@ -1016,7 +1059,7 @@ static int smack_inode_permission(struct inode *inode, int mask)
 		return -ECHILD;
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_INODE);
 	smk_ad_setfield_u_fs_inode(&ad, inode);
-	rc = smk_curacc(smk_of_inode(inode), mask, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, mask, &ad);
 	rc = smk_bu_inode(inode, mask, rc);
 	return rc;
 }
@@ -1030,6 +1073,7 @@ static int smack_inode_permission(struct inode *inode, int mask)
  */
 static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
@@ -1041,7 +1085,8 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), ns,
+			MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	return rc;
 }
@@ -1055,13 +1100,14 @@ static int smack_inode_setattr(struct dentry *dentry, struct iattr *iattr)
  */
 static int smack_inode_getattr(const struct path *path)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	struct inode *inode = d_backing_inode(path->dentry);
 	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, *path);
-	rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, MAY_READ, &ad);
 	rc = smk_bu_inode(inode, MAY_READ, rc);
 	return rc;
 }
@@ -1083,6 +1129,9 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 {
 	struct smk_audit_info ad;
 	struct smack_known *skp;
+	struct smack_known *sbj = smk_of_current();
+	struct smack_known *obj = smk_of_inode(d_backing_inode(dentry));
+	struct user_namespace *ns = ns_of_current();
 	int check_priv = 0;
 	int check_import = 0;
 	int check_star = 0;
@@ -1109,11 +1158,12 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	} else
 		rc = cap_inode_setxattr(dentry, name, value, size, flags);
 
-	if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
+	if (check_priv && !(smk_labels_valid(sbj, obj, ns) &&
+			    smack_ns_privileged(ns, CAP_MAC_ADMIN)))
 		rc = -EPERM;
 
 	if (rc == 0 && check_import) {
-		skp = size ? smk_get_label(value, size, true) : NULL;
+		skp = size ? smk_get_label(value, size, true, ns) : NULL;
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else if (skp == NULL || (check_star &&
@@ -1125,7 +1175,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
 	if (rc == 0) {
-		rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+		rc = smk_curacc(obj, ns, MAY_WRITE, &ad);
 		rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	}
 
@@ -1149,6 +1199,7 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 	struct smack_known *skp;
 	struct smack_known **skpp = NULL;
 	struct inode_smack *isp = d_backing_inode(dentry)->i_security;
+	struct user_namespace *ns = ns_of_current();
 
 	if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
@@ -1163,12 +1214,24 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 		skpp = &isp->smk_mmap;
 
 	if (skpp) {
-		skp = smk_get_label(value, size, true);
+		skp = smk_get_label(value, size, true, ns);
 
 		if (!IS_ERR(skp))
 			*skpp = skp;
 		else
 			*skpp = &smack_known_invalid;
+
+		/*
+		 * The label we get above might be a different than the one
+		 * kernel has already set before calling this function.
+		 * Be consistent and set the final value in the filesystem.
+		 * The cases for this are errors and labels being used
+		 * in a namespace where we want to store an unmapped
+		 * value in the filesystem.
+		 */
+		dentry->d_inode->i_op->setxattr(dentry, name,
+						(*skpp)->smk_known,
+						size, flags);
 	}
 }
 
@@ -1181,13 +1244,15 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
  */
 static int smack_inode_getxattr(struct dentry *dentry, const char *name)
 {
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_READ, &ad);
+	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), ns,
+			MAY_READ, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_READ, rc);
 	return rc;
 }
@@ -1204,6 +1269,9 @@ static int smack_inode_getxattr(struct dentry *dentry, const char *name)
 static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 {
 	struct inode_smack *isp;
+	struct smack_known *sbj = smk_of_current();
+	struct smack_known *obj = smk_of_inode(d_backing_inode(dentry));
+	struct user_namespace *ns = ns_of_current();
 	struct smk_audit_info ad;
 	int rc = 0;
 
@@ -1213,7 +1281,8 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
 	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
 	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
-		if (!smack_privileged(CAP_MAC_ADMIN))
+		if (!smk_labels_valid(sbj, obj, ns) ||
+		    !smack_ns_privileged(ns, CAP_MAC_ADMIN))
 			rc = -EPERM;
 	} else
 		rc = cap_inode_removexattr(dentry, name);
@@ -1224,7 +1293,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
 
-	rc = smk_curacc(smk_of_inode(d_backing_inode(dentry)), MAY_WRITE, &ad);
+	rc = smk_curacc(obj, ns, MAY_WRITE, &ad);
 	rc = smk_bu_inode(d_backing_inode(dentry), MAY_WRITE, rc);
 	if (rc != 0)
 		return rc;
@@ -1264,13 +1333,18 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	struct super_block *sbp;
 	struct inode *ip = (struct inode *)inode;
 	struct smack_known *isp = NULL;
+	struct user_namespace *ns = ns_of_current();
 	int rc = 0;
 
 	if (strcmp(name, XATTR_SMACK_SUFFIX) == 0)
 		isp = smk_of_inode(inode);
+	else if (strcmp(name, XATTR_SMACK_EXEC) == 0)
+		isp = smk_of_exec(inode);
+	else if (strcmp(name, XATTR_SMACK_MMAP) == 0)
+		isp = smk_of_mmap(inode);
 
 	if (isp) {
-		*buffer = smk_find_label_name(isp);
+		*buffer = smk_find_label_name(isp, ns);
 		if (*buffer == NULL)
 			*buffer = smack_known_huh.smk_known;
 		return strlen(*buffer);
@@ -1297,7 +1371,7 @@ static int smack_inode_getsecurity(const struct inode *inode,
 		return -EOPNOTSUPP;
 
 	if (rc == 0) {
-		*buffer = smk_find_label_name(isp);
+		*buffer = smk_find_label_name(isp, ns);
 		if (*buffer == NULL)
 			*buffer = smack_known_huh.smk_known;
 		rc = strlen(*buffer);
@@ -1408,18 +1482,19 @@ static int smack_file_ioctl(struct file *file, unsigned int cmd,
 {
 	int rc = 0;
 	struct smk_audit_info ad;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
 
 	if (_IOC_DIR(cmd) & _IOC_WRITE) {
-		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_WRITE, &ad);
 		rc = smk_bu_file(file, MAY_WRITE, rc);
 	}
 
 	if (rc == 0 && (_IOC_DIR(cmd) & _IOC_READ)) {
-		rc = smk_curacc(smk_of_inode(inode), MAY_READ, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_READ, &ad);
 		rc = smk_bu_file(file, MAY_READ, rc);
 	}
 
@@ -1437,11 +1512,12 @@ static int smack_file_lock(struct file *file, unsigned int cmd)
 {
 	struct smk_audit_info ad;
 	int rc;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
-	rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, MAY_LOCK, &ad);
 	rc = smk_bu_file(file, MAY_LOCK, rc);
 	return rc;
 }
@@ -1463,6 +1539,7 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
 {
 	struct smk_audit_info ad;
 	int rc = 0;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	switch (cmd) {
@@ -1472,14 +1549,14 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
 	case F_SETLKW:
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
-		rc = smk_curacc(smk_of_inode(inode), MAY_LOCK, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_LOCK, &ad);
 		rc = smk_bu_file(file, MAY_LOCK, rc);
 		break;
 	case F_SETOWN:
 	case F_SETSIG:
 		smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 		smk_ad_setfield_u_fs_path(&ad, file->f_path);
-		rc = smk_curacc(smk_of_inode(inode), MAY_WRITE, &ad);
+		rc = smk_curacc(smk_of_inode(inode), ns, MAY_WRITE, &ad);
 		rc = smk_bu_file(file, MAY_WRITE, rc);
 		break;
 	default:
@@ -1509,6 +1586,7 @@ static int smack_mmap_file(struct file *file,
 	struct task_smack *tsp;
 	struct smack_known *okp;
 	struct inode_smack *isp;
+	struct user_namespace *sns;
 	int may;
 	int mmay;
 	int tmay;
@@ -1519,12 +1597,16 @@ static int smack_mmap_file(struct file *file,
 
 	tsp = current_security();
 	skp = smk_of_task(tsp);
+	sns = ns_of_current();
 	isp = file_inode(file)->i_security;
 	mkp = isp->smk_mmap;
 
 	if (mkp == NULL)
 		return 0;
 
+	if (!smk_labels_valid(skp, mkp, sns))
+		return -EACCES;
+
 	rc = 0;
 
 	rcu_read_lock();
@@ -1540,6 +1622,7 @@ static int smack_mmap_file(struct file *file,
 		 */
 		if (mkp->smk_known == okp->smk_known)
 			continue;
+
 		/*
 		 * If there is a matching local rule take
 		 * that into account as well.
@@ -1619,8 +1702,10 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 				     struct fown_struct *fown, int signum)
 {
 	struct smack_known *skp;
-	struct smack_known *tkp = smk_of_task(tsk->cred->security);
+	struct smack_known *tkp;
 	struct file *file;
+	struct user_namespace *sns;
+	struct user_namespace *tns;
 	int rc;
 	struct smk_audit_info ad;
 
@@ -1628,12 +1713,17 @@ static int smack_file_send_sigiotask(struct task_struct *tsk,
 	 * struct fown_struct is never outside the context of a struct file
 	 */
 	file = container_of(fown, struct file, f_owner);
+	skp = file->f_security;
+	sns = file->f_cred->user_ns;
+
+	tkp = smk_of_task_struct(tsk);
+	tns = ns_of_task_struct(tsk);
 
 	/* we don't log here as rc can be overriden */
-	skp = file->f_security;
-	rc = smk_access(skp, tkp, MAY_WRITE, NULL);
+	rc = smk_access(skp, tkp, sns, MAY_WRITE, NULL);
 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_WRITE, rc);
-	if (rc != 0 && smack_has_privilege(tsk, CAP_MAC_OVERRIDE))
+	if (rc != 0 && smk_labels_valid(skp, tkp, sns)
+	    && smack_has_ns_privilege(tsk, tns, CAP_MAC_OVERRIDE))
 		rc = 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
@@ -1653,6 +1743,7 @@ static int smack_file_receive(struct file *file)
 	int rc;
 	int may = 0;
 	struct smk_audit_info ad;
+	struct user_namespace *ns = ns_of_current();
 	struct inode *inode = file_inode(file);
 
 	if (unlikely(IS_PRIVATE(inode)))
@@ -1668,7 +1759,7 @@ static int smack_file_receive(struct file *file)
 	if (file->f_mode & FMODE_WRITE)
 		may |= MAY_WRITE;
 
-	rc = smk_curacc(smk_of_inode(inode), may, &ad);
+	rc = smk_curacc(smk_of_inode(inode), ns, may, &ad);
 	rc = smk_bu_file(file, may, rc);
 	return rc;
 }
@@ -1688,16 +1779,19 @@ static int smack_file_receive(struct file *file)
 static int smack_file_open(struct file *file, const struct cred *cred)
 {
 	struct task_smack *tsp = cred->security;
+	struct user_namespace *ns = cred->user_ns;
 	struct inode *inode = file_inode(file);
+	struct inode_smack *isp = file_inode(file)->i_security;
 	struct smk_audit_info ad;
 	int rc;
 
-	if (smack_privileged(CAP_MAC_OVERRIDE))
+	if (smk_labels_valid(tsp->smk_task, isp->smk_inode, ns) &&
+	    smack_ns_privileged(ns, CAP_MAC_OVERRIDE))
 		return 0;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
 	smk_ad_setfield_u_fs_path(&ad, file->f_path);
-	rc = smk_access(tsp->smk_task, smk_of_inode(inode), MAY_READ, &ad);
+	rc = smk_access(tsp->smk_task, smk_of_inode(inode), ns, MAY_READ, &ad);
 	rc = smk_bu_credfile(cred, file, MAY_READ, rc);
 
 	return rc;
@@ -1852,12 +1946,13 @@ static int smk_curacc_on_task(struct task_struct *p, int access,
 				const char *caller)
 {
 	struct smk_audit_info ad;
-	struct smack_known *skp = smk_of_task_struct(p);
+	struct smack_known *tkp = smk_of_task_struct(p);
+	struct user_namespace *tns = ns_of_task_struct(p);
 	int rc;
 
 	smk_ad_init(&ad, caller, LSM_AUDIT_DATA_TASK);
 	smk_ad_setfield_u_tsk(&ad, p);
-	rc = smk_curacc(skp, access, &ad);
+	rc = smk_curacc(tkp, tns, access, &ad);
 	rc = smk_bu_task(p, access, rc);
 	return rc;
 }
@@ -1998,6 +2093,7 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	struct smk_audit_info ad;
 	struct smack_known *skp;
 	struct smack_known *tkp = smk_of_task_struct(p);
+	struct user_namespace *tns = ns_of_task_struct(p);
 	int rc;
 
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
@@ -2007,7 +2103,7 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	 * can write the receiver.
 	 */
 	if (secid == 0) {
-		rc = smk_curacc(tkp, MAY_WRITE, &ad);
+		rc = smk_curacc(tkp, tns, MAY_WRITE, &ad);
 		rc = smk_bu_task(p, MAY_WRITE, rc);
 		return rc;
 	}
@@ -2017,8 +2113,10 @@ static int smack_task_kill(struct task_struct *p, struct siginfo *info,
 	 * we can't take privilege into account.
 	 */
 	skp = smack_from_secid(secid);
-	rc = smk_access(skp, tkp, MAY_WRITE, &ad);
+
+	rc = smk_access(skp, tkp, tns, MAY_WRITE, &ad);
 	rc = smk_bu_note("USB signal", skp, tkp, MAY_WRITE, rc);
+
 	return rc;
 }
 
@@ -2073,6 +2171,7 @@ static void smack_task_to_inode(struct task_struct *p, struct inode *inode)
 static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 {
 	struct smack_known *skp = smk_of_current();
+	struct user_namespace *ns = ns_of_current();
 	struct socket_smack *ssp;
 
 	ssp = kzalloc(sizeof(struct socket_smack), gfp_flags);
@@ -2082,6 +2181,7 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 	ssp->smk_in = skp;
 	ssp->smk_out = skp;
 	ssp->smk_packet = NULL;
+	ssp->smk_ns = get_user_ns(ns);
 
 	sk->sk_security = ssp;
 
@@ -2096,7 +2196,11 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
  */
 static void smack_sk_free_security(struct sock *sk)
 {
+	struct socket_smack *ssp = sk->sk_security;
+
+	put_user_ns(ssp->smk_ns);
 	kfree(sk->sk_security);
+	sk->sk_security = NULL;
 }
 
 /**
@@ -2191,6 +2295,7 @@ static int smack_netlabel(struct sock *sk, int labeled)
 static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
 {
 	struct smack_known *skp;
+	struct user_namespace *sns;
 	int rc;
 	int sk_lbl;
 	struct smack_known *hkp;
@@ -2210,7 +2315,8 @@ static int smack_netlabel_send(struct sock *sk, struct sockaddr_in *sap)
 #endif
 		sk_lbl = SMACK_UNLABELED_SOCKET;
 		skp = ssp->smk_out;
-		rc = smk_access(skp, hkp, MAY_WRITE, &ad);
+		sns = ssp->smk_ns;
+		rc = smk_access(skp, hkp, sns, MAY_WRITE, &ad);
 		rc = smk_bu_note("IPv4 host check", skp, hkp, MAY_WRITE, rc);
 	} else {
 		sk_lbl = SMACK_CIPSO_SOCKET;
@@ -2312,6 +2418,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 	struct smk_port_label *spp;
 	struct socket_smack *ssp = sk->sk_security;
 	struct smack_known *skp;
+	struct user_namespace *sns = ssp->smk_ns;
 	unsigned short port = 0;
 	struct smack_known *object;
 	struct smk_audit_info ad;
@@ -2369,7 +2476,7 @@ auditout:
 	else
 		ad.a.u.net->v6info.daddr = address->sin6_addr;
 #endif
-	rc = smk_access(skp, object, MAY_WRITE, &ad);
+	rc = smk_access(skp, object, sns, MAY_WRITE, &ad);
 	rc = smk_bu_note("IPv6 port check", skp, object, MAY_WRITE, rc);
 	return rc;
 }
@@ -2394,12 +2501,13 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	struct inode_smack *nsp = inode->i_security;
 	struct socket_smack *ssp;
 	struct socket *sock;
+	struct user_namespace *ns = ns_of_current();
 	int rc = 0;
 
 	if (value == NULL || size > SMK_LONGLABEL || size == 0)
 		return -EINVAL;
 
-	skp = smk_import_entry(value, size);
+	skp = smk_get_label(value, size, true, ns);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
 
@@ -2584,14 +2692,14 @@ static void smack_msg_msg_free_security(struct msg_msg *msg)
 }
 
 /**
- * smack_of_shm - the smack pointer for the shm
+ * security_of_shm - the smack pointer for the shm
  * @shp: the object
  *
- * Returns a pointer to the smack value
+ * Returns a pointer to the security_smack struct
  */
-static struct smack_known *smack_of_shm(struct shmid_kernel *shp)
+static struct ipc_smack *security_of_shm(struct shmid_kernel *shp)
 {
-	return (struct smack_known *)shp->shm_perm.security;
+	return (struct ipc_smack *)shp->shm_perm.security;
 }
 
 /**
@@ -2603,9 +2711,16 @@ static struct smack_known *smack_of_shm(struct shmid_kernel *shp)
 static int smack_shm_alloc_security(struct shmid_kernel *shp)
 {
 	struct kern_ipc_perm *isp = &shp->shm_perm;
-	struct smack_known *skp = smk_of_current();
+	struct ipc_smack *ssp;
 
-	isp->security = skp;
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
+
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
+
+	isp->security = ssp;
 	return 0;
 }
 
@@ -2618,7 +2733,10 @@ static int smack_shm_alloc_security(struct shmid_kernel *shp)
 static void smack_shm_free_security(struct shmid_kernel *shp)
 {
 	struct kern_ipc_perm *isp = &shp->shm_perm;
+	struct ipc_smack *ssp = isp->security;
 
+	put_user_ns(ssp->smk_ns);
+	kfree(isp->security);
 	isp->security = NULL;
 }
 
@@ -2631,7 +2749,7 @@ static void smack_shm_free_security(struct shmid_kernel *shp)
  */
 static int smk_curacc_shm(struct shmid_kernel *shp, int access)
 {
-	struct smack_known *ssp = smack_of_shm(shp);
+	struct ipc_smack *ssp = security_of_shm(shp);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -2639,8 +2757,8 @@ static int smk_curacc_shm(struct shmid_kernel *shp, int access)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = shp->shm_perm.id;
 #endif
-	rc = smk_curacc(ssp, access, &ad);
-	rc = smk_bu_current("shm", ssp, access, rc);
+	rc = smk_curacc(ssp->smk_known, ssp->smk_ns, access, &ad);
+	rc = smk_bu_current("shm", ssp->smk_known, access, rc);
 	return rc;
 }
 
@@ -2711,14 +2829,14 @@ static int smack_shm_shmat(struct shmid_kernel *shp, char __user *shmaddr,
 }
 
 /**
- * smack_of_sem - the smack pointer for the sem
+ * security_of_sem - the smack pointer for the sem
  * @sma: the object
  *
- * Returns a pointer to the smack value
+ * Returns a pointer to the ipc_smack struct
  */
-static struct smack_known *smack_of_sem(struct sem_array *sma)
+static struct ipc_smack *security_of_sem(struct sem_array *sma)
 {
-	return (struct smack_known *)sma->sem_perm.security;
+	return (struct ipc_smack *)sma->sem_perm.security;
 }
 
 /**
@@ -2730,9 +2848,16 @@ static struct smack_known *smack_of_sem(struct sem_array *sma)
 static int smack_sem_alloc_security(struct sem_array *sma)
 {
 	struct kern_ipc_perm *isp = &sma->sem_perm;
-	struct smack_known *skp = smk_of_current();
+	struct ipc_smack *ssp;
 
-	isp->security = skp;
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
+
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
+
+	isp->security = ssp;
 	return 0;
 }
 
@@ -2745,7 +2870,10 @@ static int smack_sem_alloc_security(struct sem_array *sma)
 static void smack_sem_free_security(struct sem_array *sma)
 {
 	struct kern_ipc_perm *isp = &sma->sem_perm;
+	struct ipc_smack *ssp = isp->security;
 
+	put_user_ns(ssp->smk_ns);
+	kfree(isp->security);
 	isp->security = NULL;
 }
 
@@ -2758,7 +2886,7 @@ static void smack_sem_free_security(struct sem_array *sma)
  */
 static int smk_curacc_sem(struct sem_array *sma, int access)
 {
-	struct smack_known *ssp = smack_of_sem(sma);
+	struct ipc_smack *ssp = security_of_sem(sma);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -2766,8 +2894,8 @@ static int smk_curacc_sem(struct sem_array *sma, int access)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = sma->sem_perm.id;
 #endif
-	rc = smk_curacc(ssp, access, &ad);
-	rc = smk_bu_current("sem", ssp, access, rc);
+	rc = smk_curacc(ssp->smk_known, ssp->smk_ns, access, &ad);
+	rc = smk_bu_current("sem", ssp->smk_known, access, rc);
 	return rc;
 }
 
@@ -2852,9 +2980,16 @@ static int smack_sem_semop(struct sem_array *sma, struct sembuf *sops,
 static int smack_msg_queue_alloc_security(struct msg_queue *msq)
 {
 	struct kern_ipc_perm *kisp = &msq->q_perm;
-	struct smack_known *skp = smk_of_current();
+	struct ipc_smack *ssp;
+
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
+
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
 
-	kisp->security = skp;
+	kisp->security = ssp;
 	return 0;
 }
 
@@ -2867,19 +3002,22 @@ static int smack_msg_queue_alloc_security(struct msg_queue *msq)
 static void smack_msg_queue_free_security(struct msg_queue *msq)
 {
 	struct kern_ipc_perm *kisp = &msq->q_perm;
+	struct ipc_smack *ssp = kisp->security;
 
+	put_user_ns(ssp->smk_ns);
+	kfree(kisp->security);
 	kisp->security = NULL;
 }
 
 /**
- * smack_of_msq - the smack pointer for the msq
+ * security_of_msq - the smack pointer for the msq
  * @msq: the object
  *
- * Returns a pointer to the smack label entry
+ * Returns a pointer to the ipc_smack struct
  */
-static struct smack_known *smack_of_msq(struct msg_queue *msq)
+static struct ipc_smack *security_of_msq(struct msg_queue *msq)
 {
-	return (struct smack_known *)msq->q_perm.security;
+	return (struct ipc_smack *)msq->q_perm.security;
 }
 
 /**
@@ -2891,7 +3029,7 @@ static struct smack_known *smack_of_msq(struct msg_queue *msq)
  */
 static int smk_curacc_msq(struct msg_queue *msq, int access)
 {
-	struct smack_known *msp = smack_of_msq(msq);
+	struct ipc_smack *msp = security_of_msq(msq);
 	struct smk_audit_info ad;
 	int rc;
 
@@ -2899,8 +3037,8 @@ static int smk_curacc_msq(struct msg_queue *msq, int access)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = msq->q_perm.id;
 #endif
-	rc = smk_curacc(msp, access, &ad);
-	rc = smk_bu_current("msq", msp, access, rc);
+	rc = smk_curacc(msp->smk_known, msp->smk_ns, access, &ad);
+	rc = smk_bu_current("msq", msp->smk_known, access, rc);
 	return rc;
 }
 
@@ -2994,7 +3132,7 @@ static int smack_msg_queue_msgrcv(struct msg_queue *msq, struct msg_msg *msg,
  */
 static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 {
-	struct smack_known *iskp = ipp->security;
+	struct ipc_smack *isp = ipp->security;
 	int may = smack_flags_to_may(flag);
 	struct smk_audit_info ad;
 	int rc;
@@ -3003,8 +3141,8 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_IPC);
 	ad.a.u.ipc_id = ipp->id;
 #endif
-	rc = smk_curacc(iskp, may, &ad);
-	rc = smk_bu_current("svipc", iskp, may, rc);
+	rc = smk_curacc(isp->smk_known, isp->smk_ns, may, &ad);
+	rc = smk_bu_current("svipc", isp->smk_known, may, rc);
 	return rc;
 }
 
@@ -3015,9 +3153,9 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
  */
 static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
 {
-	struct smack_known *iskp = ipp->security;
+	struct ipc_smack *iskp = ipp->security;
 
-	*secid = iskp->smk_secid;
+	*secid = iskp->smk_known->smk_secid;
 }
 
 /**
@@ -3251,13 +3389,14 @@ unlockandout:
 static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 {
 	struct smack_known *skp = smk_of_task_struct(p);
+	struct user_namespace *ns = ns_of_current();
 	char *cp;
 	int slen;
 
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	cp = smk_find_label_name(skp);
+	cp = smk_find_label_name(skp, ns);
 	if (cp == NULL)
 		cp = smack_known_huh.smk_known;
 	cp = kstrdup(cp, GFP_KERNEL);
@@ -3287,6 +3426,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	struct task_smack *tsp;
 	struct cred *new;
 	struct smack_known *skp;
+	struct user_namespace *ns;
 
 	/*
 	 * Changing another process' Smack value is too dangerous
@@ -3295,7 +3435,9 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	if (p != current)
 		return -EPERM;
 
-	if (!smack_privileged(CAP_MAC_ADMIN))
+	ns = ns_of_current();
+
+	if (!smack_ns_privileged(ns, CAP_MAC_ADMIN))
 		return -EPERM;
 
 	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
@@ -3304,7 +3446,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
 	if (strcmp(name, "current") != 0)
 		return -EINVAL;
 
-	skp = smk_get_label(value, size, true);
+	skp = smk_get_label(value, size, true, ns);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
 
@@ -3344,23 +3486,27 @@ static int smack_unix_stream_connect(struct sock *sock,
 	struct smack_known *okp_out = osp->smk_out;
 	struct smack_known *skp_in = ssp->smk_in;
 	struct smack_known *okp_in = osp->smk_in;
+	struct user_namespace *sns = ssp->smk_ns;
+	struct user_namespace *ons = osp->smk_ns;
 	struct smk_audit_info ad;
 	int rc = 0;
 #ifdef CONFIG_AUDIT
 	struct lsm_network_audit net;
 #endif
 
-	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
+	if (!smack_ns_privileged(ons, CAP_MAC_OVERRIDE) ||
+	    !smk_labels_valid(skp_out, okp_in, sns) ||
+	    !smk_labels_valid(okp_out, skp_in, ons)) {
 #ifdef CONFIG_AUDIT
 		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
 		smk_ad_setfield_u_net_sk(&ad, other);
 #endif
-		rc = smk_access(skp_out, okp_in, MAY_WRITE, &ad);
+		rc = smk_access(skp_out, okp_in, sns, MAY_WRITE, &ad);
 		rc = smk_bu_note("UDS connect", skp_out, okp_in, MAY_WRITE, rc);
 		if (rc == 0) {
-			rc = smk_access(okp_out, skp_in, MAY_WRITE, &ad);
+			rc = smk_access(okp_out, skp_in, ons, MAY_WRITE, &ad);
 			rc = smk_bu_note("UDS connect", okp_out, skp_in,
-						MAY_WRITE, rc);
+					 MAY_WRITE, rc);
 		}
 	}
 
@@ -3387,6 +3533,8 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 {
 	struct socket_smack *ssp = sock->sk->sk_security;
 	struct socket_smack *osp = other->sk->sk_security;
+	struct user_namespace *sns = ssp->smk_ns;
+	struct user_namespace *ons = osp->smk_ns;
 	struct smk_audit_info ad;
 	int rc;
 
@@ -3397,10 +3545,11 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 	smk_ad_setfield_u_net_sk(&ad, other->sk);
 #endif
 
-	if (smack_privileged(CAP_MAC_OVERRIDE))
+	if (smk_labels_valid(ssp->smk_out, osp->smk_in, sns) &&
+	    smack_ns_privileged(ons, CAP_MAC_OVERRIDE))
 		return 0;
 
-	rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);
+	rc = smk_access(ssp->smk_out, osp->smk_in, sns, MAY_WRITE, &ad);
 	rc = smk_bu_note("UDS send", ssp->smk_out, osp->smk_in, MAY_WRITE, rc);
 	return rc;
 }
@@ -3640,7 +3789,7 @@ access_check:
 		 * This is the simplist possible security model
 		 * for networking.
 		 */
-		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+		rc = smk_access(skp, ssp->smk_in, ssp->smk_ns, MAY_WRITE, &ad);
 		rc = smk_bu_note("IPv4 delivery", skp, ssp->smk_in,
 					MAY_WRITE, rc);
 		if (rc != 0)
@@ -3662,7 +3811,7 @@ access_check:
 		ad.a.u.net->netif = skb->skb_iif;
 		ipv6_skb_to_auditdata(skb, &ad.a, NULL);
 #endif /* CONFIG_AUDIT */
-		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+		rc = smk_access(skp, ssp->smk_in, ssp->smk_ns, MAY_WRITE, &ad);
 		rc = smk_bu_note("IPv6 delivery", skp, ssp->smk_in,
 					MAY_WRITE, rc);
 #else /* CONFIG_SECURITY_SMACK_NETFILTER */
@@ -3875,7 +4024,7 @@ access_check:
 	 * Receiving a packet requires that the other end be able to write
 	 * here. Read access is not required.
 	 */
-	rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+	rc = smk_access(skp, ssp->smk_in, ssp->smk_ns, MAY_WRITE, &ad);
 	rc = smk_bu_note("IPv4 connect", skp, ssp->smk_in, MAY_WRITE, rc);
 	if (rc != 0)
 		return rc;
@@ -3979,6 +4128,7 @@ static int smack_key_permission(key_ref_t key_ref,
 	struct key *keyp;
 	struct smk_audit_info ad;
 	struct smack_known *tkp = smk_of_task(cred->security);
+	struct user_namespace *tns = cred->user_ns;
 	int request = 0;
 	int rc;
 
@@ -4005,7 +4155,7 @@ static int smack_key_permission(key_ref_t key_ref,
 		request = MAY_READ;
 	if (perm & (KEY_NEED_WRITE | KEY_NEED_LINK | KEY_NEED_SETATTR))
 		request = MAY_WRITE;
-	rc = smk_access(tkp, keyp->security, request, &ad);
+	rc = smk_access(tkp, keyp->security, tns, request, &ad);
 	rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
 	return rc;
 }
@@ -4022,6 +4172,7 @@ static int smack_key_permission(key_ref_t key_ref,
 static int smack_key_getsecurity(struct key *key, char **_buffer)
 {
 	struct smack_known *skp = key->security;
+	struct user_namespace *ns = ns_of_current();
 	size_t length;
 	char *copy;
 
@@ -4030,7 +4181,7 @@ static int smack_key_getsecurity(struct key *key, char **_buffer)
 		return 0;
 	}
 
-	copy = smk_find_label_name(skp);
+	copy = smk_find_label_name(skp, ns);
 	if (copy == NULL)
 		copy = smack_known_huh.smk_known;
 	copy = kstrdup(copy, GFP_KERNEL);
@@ -4208,6 +4359,11 @@ static inline void smack_userns_free(struct user_namespace *ns)
 static inline int smack_userns_setns(struct nsproxy *nsproxy,
 				     struct user_namespace *ns)
 {
+	struct smack_known *skp = smk_of_current();
+
+	if (smk_find_mapped(skp, ns) == NULL)
+		return -EACCES;
+
 	return 0;
 }
 
diff --git a/security/smack/smack_ns.c b/security/smack/smack_ns.c
index 141a836..819c490 100644
--- a/security/smack/smack_ns.c
+++ b/security/smack/smack_ns.c
@@ -206,6 +206,45 @@ unlockout:
 	return sknp;
 }
 
+/**
+ * smk_labels_valid - A helper to check whether labels are valid/mapped
+ *                    in the namespace and can be used there
+ * @sbj: a subject label to be checked
+ * @obj: an object label to be checked
+ * @ns: user namespace to check against (usually subject's)
+ *
+ * Returns true if both valid/mapped, false otherwise.
+ * This helper is mostly used while checking capabilities.
+ * The access functions check the validity of labels by themselves.
+ */
+bool smk_labels_valid(struct smack_known *sbj, struct smack_known *obj,
+		      struct user_namespace *ns)
+{
+	struct user_namespace *user_ns;
+
+	/*
+	 * labels are always valid if there is no map
+	 * (init_user_ns or unmapped descendants)
+	 */
+	user_ns = smk_find_mapped_ns(ns);
+	if (user_ns == NULL)
+		return true;
+
+	/*
+	 * If we have a map though, both labels need to be mapped.
+	 */
+	if (__smk_find_mapped(sbj, user_ns) == NULL)
+		return false;
+	if (__smk_find_mapped(obj, user_ns) == NULL)
+		return false;
+
+	return true;
+}
+
+/*
+ * proc mapping operations
+ */
+
 static void *proc_smack_map_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	struct smack_known *skp;
@@ -253,7 +292,7 @@ static int proc_smack_map_seq_show(struct seq_file *seq, void *v)
 	 * to show identity in this syntax without printing all the labels.
 	 */
 	if (smk_find_mapped_ns(ns) == NULL) {
-		seq_puts("This namespace is not mapped.\n");
+		seq_puts(seq, "This namespace is not mapped.\n");
 	} else {
 		sknp = smk_find_mapped(skp, ns);
 		if (sknp)
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 5ec1e8e..7196861 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -345,13 +345,15 @@ static int smk_fill_rule(const char *subject, const char *object,
 				struct smack_parsed_rule *rule, int import,
 				int len)
 {
-	rule->smk_subject = smk_get_label(subject, len, import);
+	struct user_namespace *ns = ns_of_current();
+
+	rule->smk_subject = smk_get_label(subject, len, import, ns);
 	if (IS_ERR(rule->smk_subject))
 		return PTR_ERR(rule->smk_subject);
 	if (rule->smk_subject == NULL)
 		return -ENOENT;
 
-	rule->smk_object = smk_get_label(object, len, import);
+	rule->smk_object = smk_get_label(object, len, import, ns);
 	if (IS_ERR(rule->smk_object))
 		return PTR_ERR(rule->smk_object);
 	if (rule->smk_object == NULL)
@@ -586,6 +588,7 @@ static void smk_seq_stop(struct seq_file *s, void *v)
 
 static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 {
+	struct user_namespace *ns = ns_of_current();
 	char *sbj;
 	char *obj;
 
@@ -594,6 +597,7 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	 * interface file (/smack/load or /smack/load2)
 	 * because you should expect to be able to write
 	 * anything you read back.
+	 * Show only fully mapped rules in a namespace (both labels mapped).
 	 */
 	if (strlen(srp->smk_subject->smk_known) >= max ||
 	    strlen(srp->smk_object->smk_known) >= max)
@@ -602,8 +606,8 @@ static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
 	if (srp->smk_access == 0)
 		return;
 
-	sbj = smk_find_label_name(srp->smk_subject);
-	obj = smk_find_label_name(srp->smk_object);
+	sbj = smk_find_label_name(srp->smk_subject, ns);
+	obj = smk_find_label_name(srp->smk_object, ns);
 
 	if (sbj == NULL || obj == NULL)
 		return;
@@ -798,6 +802,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	struct smack_known *skp =
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
+	struct user_namespace *ns = ns_of_current();
 	char sep = '/';
 	char *cp;
 	int i;
@@ -813,7 +818,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	if (strlen(skp->smk_known) >= SMK_LABELLEN)
 		return 0;
 
-	cp = smk_find_label_name(skp);
+	cp = smk_find_label_name(skp, ns);
 	if (cp == NULL)
 		return 0;
 
@@ -866,6 +871,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 {
 	struct smack_known *skp;
 	struct netlbl_lsm_secattr ncats;
+	struct user_namespace *ns = ns_of_current();
 	char mapcatset[SMK_CIPSOLEN];
 	int maplevel;
 	unsigned int cat;
@@ -906,7 +912,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 	 */
 	mutex_lock(&smack_cipso_lock);
 
-	skp = smk_get_label(rule, 0, true);
+	skp = smk_get_label(rule, 0, true, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -994,11 +1000,12 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
 	struct smack_known *skp =
 		 list_entry(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
+	struct user_namespace *ns = ns_of_current();
 	char sep = '/';
 	char *cp;
 	int i;
 
-	cp = smk_find_label_name(skp);
+	cp = smk_find_label_name(skp, ns);
 	if (cp == NULL)
 		return 0;
 
@@ -1085,7 +1092,8 @@ static int netlbladdr_seq_show(struct seq_file *s, void *v)
 	unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
 	int maskn;
 	u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
-	char *label = smk_find_label_name(skp->smk_label);
+	struct user_namespace *ns = ns_of_current();
+	char *label = smk_find_label_name(skp->smk_label, ns);
 
 	if (label == NULL)
 		return 0;
@@ -1182,6 +1190,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	int rc;
 	struct netlbl_audit audit_info;
 	struct in_addr mask;
+	struct user_namespace *ns = ns_of_current();
 	unsigned int m;
 	int found;
 	u32 mask_bits = (1<<31);
@@ -1239,7 +1248,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
 	 * If smack begins with '-', it is an option, don't import it
 	 */
 	if (smack[0] != '-') {
-		skp = smk_get_label(smack, 0, true);
+		skp = smk_get_label(smack, 0, true, ns);
 		if (IS_ERR(skp)) {
 			rc = PTR_ERR(skp);
 			goto free_out;
@@ -1567,6 +1576,7 @@ static const struct file_operations smk_mapped_ops = {
 static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
+	struct user_namespace *ns = ns_of_current();
 	ssize_t rc;
 	char *cp;
 	int asize;
@@ -1579,7 +1589,7 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 	 */
 	mutex_lock(&smack_ambient_lock);
 
-	cp = smk_find_label_name(smack_net_ambient);
+	cp = smk_find_label_name(smack_net_ambient, ns);
 	if (cp == NULL)
 		cp = smack_known_huh.smk_known;
 
@@ -1608,6 +1618,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 				 size_t count, loff_t *ppos)
 {
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	char *oldambient;
 	char *data;
 	int rc = count;
@@ -1624,7 +1635,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
 		goto out;
 	}
 
-	skp = smk_get_label(data, count, true);
+	skp = smk_get_label(data, count, true, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out;
@@ -1664,12 +1675,13 @@ static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
 	char *smack = "";
 	ssize_t rc = -EINVAL;
 	int asize;
+	struct user_namespace *ns = ns_of_current();
 
 	if (*ppos != 0)
 		return 0;
 
 	if (smack_onlycap != NULL) {
-		smack = smk_find_label_name(smack_onlycap);
+		smack = smk_find_label_name(smack_onlycap, ns);
 		if (smack == NULL)
 			smack = smack_known_huh.smk_known;
 	}
@@ -1696,6 +1708,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 {
 	char *data;
 	struct smack_known *skp = smk_of_task(current->cred->security);
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -1727,7 +1740,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_get_label(data, count, true);
+	skp = smk_get_label(data, count, true, ns);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -1764,12 +1777,13 @@ static ssize_t smk_read_unconfined(struct file *filp, char __user *buf,
 	char *smack = "";
 	ssize_t rc = -EINVAL;
 	int asize;
+	struct user_namespace *ns = ns_of_current();
 
 	if (*ppos != 0)
 		return 0;
 
 	if (smack_unconfined != NULL) {
-		smack = smk_find_label_name(smack_unconfined);
+		smack = smk_find_label_name(smack_unconfined, ns);
 		if (smack == NULL)
 			smack = smack_known_huh.smk_known;
 	}
@@ -1796,6 +1810,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 {
 	char *data;
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -1819,7 +1834,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
 	 *
 	 * But do so only on invalid label, not on system errors.
 	 */
-	skp = smk_get_label(data, count, true);
+	skp = smk_get_label(data, count, true, ns);
 	if (PTR_ERR(skp) == -EINVAL)
 		skp = NULL;
 	else if (IS_ERR(skp)) {
@@ -1991,6 +2006,7 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos, int format)
 {
 	struct smack_parsed_rule rule;
+	struct user_namespace *ns = ns_of_current();
 	char *data;
 	int res;
 
@@ -2010,7 +2026,7 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf,
 	}
 
 	if (res >= 0)
-		res = smk_access(rule.smk_subject, rule.smk_object,
+		res = smk_access(rule.smk_subject, rule.smk_object, ns,
 				 rule.smk_access1, NULL);
 	else if (res != -ENOENT)
 		return res;
@@ -2220,6 +2236,7 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 	struct smack_rule *sp;
 	struct list_head *rule_list;
 	struct mutex *rule_lock;
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (*ppos != 0)
@@ -2240,7 +2257,7 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 		goto free_out;
 	}
 
-	skp = smk_get_label(data, count, false);
+	skp = smk_get_label(data, count, false, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto free_out;
@@ -2322,6 +2339,7 @@ static const struct file_operations smk_change_rule_ops = {
 static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 				size_t cn, loff_t *ppos)
 {
+	struct user_namespace *ns = ns_of_current();
 	ssize_t rc = -EINVAL;
 	char *cp;
 	int asize;
@@ -2332,7 +2350,7 @@ static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 	if (smack_syslog_label == NULL)
 		cp = smack_known_star.smk_known;
 	else {
-		cp = smk_find_label_name(smack_syslog_label);
+		cp = smk_find_label_name(smack_syslog_label, ns);
 		if (cp == NULL)
 			cp = smack_known_huh.smk_known;
 	}
@@ -2359,6 +2377,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 {
 	char *data;
 	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -2371,7 +2390,7 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (copy_from_user(data, buf, count) != 0)
 		rc = -EFAULT;
 	else {
-		skp = smk_get_label(data, count, true);
+		skp = smk_get_label(data, count, true, ns);
 		if (IS_ERR(skp))
 			rc = PTR_ERR(skp);
 		else
-- 
2.1.0

[PATCH v2 7/7] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

Adds Documentation/smack-namespace.txt.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 Documentation/security/00-INDEX            |   2 +
 Documentation/security/Smack-namespace.txt | 231 +++++++++++++++++++++++++++++
 MAINTAINERS                                |   1 +
 security/smack/Kconfig                     |   2 +
 4 files changed, 236 insertions(+)
 create mode 100644 Documentation/security/Smack-namespace.txt

diff --git a/Documentation/security/00-INDEX b/Documentation/security/00-INDEX
index 45c82fd..c03a220 100644
--- a/Documentation/security/00-INDEX
+++ b/Documentation/security/00-INDEX
@@ -6,6 +6,8 @@ SELinux.txt
 	- how to get started with the SELinux security enhancement.
 Smack.txt
 	- documentation on the Smack Linux Security Module.
+Smack-namespace.txt
+	- documentation on the Smack namespace implementation.
 Yama.txt
 	- documentation on the Yama Linux Security Module.
 apparmor.txt
diff --git a/Documentation/security/Smack-namespace.txt b/Documentation/security/Smack-namespace.txt
new file mode 100644
index 0000000..85197ff
--- /dev/null
+++ b/Documentation/security/Smack-namespace.txt
@@ -0,0 +1,231 @@
+
+                                      "Quis custodiet ipsos custodes?"
+                                                 - Satires of Juvenal
+
+
+--- What is a Smack namespace ---
+
+Smack namespace was developed to make it possible for Smack to work
+nicely with Linux containers where there is a full operating system
+with its own init inside the namespace. Such a system working with
+Smack expects to have at least partially working SMACK_MAC_ADMIN to be
+able to change labels of processes and files. This is required to be
+able to securely start applications under the control of Smack and
+manage their access rights.
+
+It was implemented using new LSM hooks added to the user namespace
+that were developed together with Smack namespace.
+
+
+--- Design ideas ---
+
+"Smack namespace" is rather "Smack labels namespace" as not the whole
+MAC is namespaced, only the labels. There is a great analogy between
+Smack labels namespace and the user namespace part that remaps UIDs.
+
+The idea is to create a map of labels for a namespace so the namespace
+is only allowed to use those labels. Smack rules are always the same
+as in the init namespace (limited only by what labels are mapped) and
+cannot be manipulated from the child namespace. The map is actually
+only for labels' names. The underlying structures for labels remain
+the same. The filesystem also stores the "unmapped" labels from the
+init namespace.
+
+Let's say we have those labels in the init namespace:
+label1
+label2
+label3
+
+and those rules:
+label1 label2 rwx
+label1 label3 rwx
+label2 label3 rwx
+
+We create a map for a namespace:
+label1 -> mapped1
+label2 -> mapped2
+
+This means that 'label3' is completely invisible in the namespace. As if
+it didn't exist. All the rules that include it are ignored.
+
+Effectively in the namespace we have only one rule:
+mapped1 mapped2 rwx
+
+Which in reality is:
+label1 label2 rwx
+
+All requests to access an object with a 'label3' will be denied. If it
+ever comes to a situation where 'label3' would have to be printed
+(e.g. reading an exec or mmap label from a file to which we have
+access) then huh sign '?' will be printed instead.
+
+All the operations in the namespace on the remaining labels will have
+to be performed using their mapped names. Things like changing own
+process's label, changing filesystem label. Labels will also be
+printed with their mapped names.
+
+You cannot import new labels in a namespace. Every operation that
+would do so in an init namespace will return an error in the child
+namespace. You cannot assign an unmapped or not existing label to an
+object. You can only operate on labels that have been explicitly
+mapped.
+
+
+--- Capabilities ---
+
+Enabling Smack related capabilities (CAP_MAC_ADMIN and
+CAP_MAC_OVERRIDE) is main goal of Smack namespace, so it can work
+properly in the container. And those capabilities do work to some
+extent. In several places where capabilities are checked compatibility
+with Smack namespace has been introduced. Capabilities are of course
+limited to operate only on mapped labels.
+
+CAP_MAC_OVERRIDE works fully, will allow you to ignore Smack access
+rules, but only between objects that have labels mapped. So in the
+example above having this CAP will allow e.g. label2 to write to
+label1, but will not allow any access to label3.
+
+With CAP_MAC_ADMIN the following operations has been allowed inside
+the namespace:
+- setting and removing xattr on files, including the security.* ones
+- setting process's own label (/proc/self/attr/current)
+- mounting in a privileged Smack mode, which means one can specify
+  additional mount options like: smackfsdef, smackfsfloor etc.
+
+Again this is also allowed only on the mapped labels. Labels on the
+filesystem will be stored in unmapped form so they are preserved
+through reboots.
+
+Such a namespace construct allows e.g. systemd (with Smack support)
+working in a container to assign labels properly to daemons and other
+processes.
+
+
+--- Usage ---
+
+Smack namespace is written using LSM hooks inside user namespace. That
+means it's connected to it.
+
+To create a new Smack namespace you need to unshare() user namespace
+as usual. If that is all you do though, than there is no difference to
+what is now. To activate the Smack namespace you need to fill the
+labels' map. It is in a file /proc/$PID/smack_map.
+
+By default the map is empty and Smack namespaces are inactive (labels
+are taken directly from a parent namespace). It also means that the
+Smack capabilities will be inactive. After you fill the map it starts
+to take effect in the namespace and Smack capabilities (only on mapped
+labels) start to work.
+
+Due to the way Smack works only CAP_MAC_ADMIN from the parent
+namespace (init_user_ns for now, see the "Current limitations" below)
+is allowed to fill the map. That means that an unprivileged user is
+still allowed to create the user namespace but it will not be able to
+fill the labels' map (activate Smack namespace). An administrator
+intervention is required.
+
+The attr_map write format is:
+unmapped_label mapped_label
+
+When reading the file it shows an active map for a namespace the
+process in question is in in the format:
+unmapped_label -> mapped_label
+
+If the smack_map file is empty it means the namespace is not mapped
+and Smack namespace is inactive (no mappings, MAC related capabilities
+behave as they did before, meaning they are active only in
+init_user_ns). For init_user_ns the map will always be empty.
+
+Writing to the map file is not disabled after the first write as it is
+in uid_map. For Smack we have no means to map ranges of labels, hence
+it can really be advantageous to be able to expand the map later
+on. But you can only add to the map. You cannot remove already mapped
+labels. You cannot change the already existing mappings. Also mappings
+has to be 1-1. All requests to create a map where either the unmapped
+or the mapped label already exists in the map will be denied.
+
+setns() with Smack namespace active has an additional check that the
+label of a process that is calling setns() has to be already mapped in
+the target Smack namespace for the call to succeed.
+
+
+--- Special labels ---
+
+Smack is using some special labels that have built-in rules. Things
+like floor '_', dash '^', star '*', etc. Those labels are not
+automatically mapped to the namespace. Moreover, you can choose to map
+a different label from the init namespace to behave e.g. like floor
+inside the namespace.
+
+Let's say we have no rules and those labels in the init namespace:
+_
+floor_to_be
+label
+
+Both 'label' and 'floor_to_be' can read objects with '_'. But they
+have no access rights to each other.
+
+Now let's create a map like this:
+_             ordinary_label
+floor_to_be   _
+label         mapped
+
+Right now label 'mapped' can read label '_' which means that
+effectively inside this namespace label 'label' has gained read access
+to the 'floor_to_be'. The label 'ordinary_label' is exactly it, an
+ordinary label that the built-in rules no longer apply to inside the
+namespace.
+
+To sum up, special labels in the namespace behave the same as in the
+init namespace. Not the original special labels though, but the ones
+we map to specials. This is the only case where a namespace can have
+access rights the init namespace does not have (like the 'label' to
+'floor_to_be' in the example above).
+
+Of course mappings like these are perfectly legal:
+_   _
+*   *
+^   ^
+
+
+--- Current limitations ---
+
+The Smack namespace is not hierarchical yet. It is currently not
+possible to fill a smack_map of a nested user namespace (you can still
+create nested user namespace, it will just inherit its parent's map
+and won't have active Smack capabilities). When hierarchy will be
+implemented the process creating another namespace will be allowed to
+map only labels that it has permission to itself (those that it has in
+its own map).
+
+Special files inside the virtual smackfs needs to be reviewed whether
+it's beneficial to have some of their functionality namespaced as well
+(e.g. onlycap, syslog. ambient, etc). This would increase
+CAP_MAC_ADMIN privileges inside the namespace.
+
+
+--- Error codes ---
+
+While working in the namespace patches the error codes has been made
+to propagate properly from a place they occurred. New error codes has
+also been introduced for Smack in the context of namespace usage. This
+is a complete summary of error codes used throughout the Smack now:
+
+ENOMEM      and other system errors that might come from low level
+            kernel functions like memory allocations
+EOPNOTSUPP  means the underlying system operation is not
+            supported (eg. getxattr)
+EINVAL      means invalid syntax (e.g. empty label or one starting
+            with '-')
+EEXIST      when creating map means that a label is already mapped
+EBADR       is used for wrong namespace usage:
+            - trying to import a label inside a namespace (like trying
+              to use an unmapped label that would otherwise be imported)
+            - trying to create a Smack label map in the init namespace
+ENOENT      when failed to find a label we expected to exist (will not
+            be propagated to user-space)
+EPERM       means no permission to operate on an object, e.g. due to
+            insufficient capabilities or simply because the object
+	    cannot be operated on in the current context
+EACCESS     when access has been denied due to Smack access checks
+            (including object being outside of a namespace)
diff --git a/MAINTAINERS b/MAINTAINERS
index 2e5bbc0..66ab25b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9059,6 +9059,7 @@ W:	http://schaufler-ca.com
 T:	git git://git.gitorious.org/smack-next/kernel.git
 S:	Maintained
 F:	Documentation/security/Smack.txt
+F:	Documentation/security/Smack-namespace.txt
 F:	security/smack/
 
 DRIVERS FOR ADAPTIVE VOLTAGE SCALING (AVS)
diff --git a/security/smack/Kconfig b/security/smack/Kconfig
index b19a7fb..a6e0f3f 100644
--- a/security/smack/Kconfig
+++ b/security/smack/Kconfig
@@ -49,4 +49,6 @@ config SECURITY_SMACK_NS
 	  This enables Smack namespace that makes it possible to map
 	  specific labels within user namespace (analogously to mapping
 	  UIDs) and to gain MAC capabilities over them.
+	  Documentation is availabile here:
+	  Documentation/security/Smack-namespace.txt
 	  If you are unsure how to answer this question, answer N.
-- 
2.1.0

Re: [PATCH v2 0/7] Smack namespace

[Stephen Smalley]

On 05/25/2015 08:32 AM, Lukasz Pawelczyk wrote:
> --- Design ideas ---
> 
> "Smack namespace" is rather "Smack labels namespace" as not the whole
> MAC is namespaced, only the labels. There is a great analogy between
> Smack labels namespace and the user namespace part that remaps UIDs.
> 
> The idea is to create a map of labels for a namespace so the namespace
> is only allowed to use those labels. Smack rules are always the same
> as in the init namespace (limited only by what labels are mapped) and
> cannot be manipulated from the child namespace. The map is actually
> only for labels' names. The underlying structures for labels remain
> the same. The filesystem also stores the "unmapped" labels from the
> init namespace.

How do you achieve that without introducing additional hooks or
reworking the current hooks in the setxattr code path?  At present, the
security module is allowed to rewrite getxattr requests on the
security.* namespace but it isn't allowed to do that for setxattr, so if
the process invokes setxattr with a mapped label, then it will be the
mapped label that gets passed to the filesystem implementation, not the
unmapped label.  The security module may internally store it in unmapped
form and may even return that upon getxattr() calls, but if you then
reboot the system and later fetch from the filesystem, it will get the
mapped label value.

> --- Usage ---
> 
> Smack namespace is written using LSM hooks inside user namespace. That
> means it's connected to it.
> 
> To create a new Smack namespace you need to unshare() user namespace
> as usual. If that is all you do though, than there is no difference to
> what is now. To activate the Smack namespace you need to fill the
> labels' map. It is in a file /proc/$PID/smack_map.

This should be /proc/$PID/attr/label_map or similar, modeled after the
existing /proc/$PID/attr/current and similar nodes.  Then it isn't
module-specific and can be reused for other modules.

> Writing to the map file is not disabled after the first write as it is
> in uid_map. For Smack we have no means to map ranges of labels, hence
> it can really be advantageous to be able to expand the map later
> on. But you can only add to the map. You cannot remove already mapped
> labels. You cannot change the already existing mappings. Also mappings
> has to be 1-1. All requests to create a map where either the unmapped
> or the mapped label already exists in the map will be denied.

Isn't it a concern that I can then add additional labels to the mapping
for which I am not authorized?  Or is this mitigated by the fact that I
cannot alter the rules?  What about the situation for the predefined
labels in Smack - are you assuming that they will always be mapped up
front in the mapping file?

Re: [PATCH v2 0/7] Smack namespace

[Casey Schaufler]

On 5/25/2015 5:32 AM, Lukasz Pawelczyk wrote:
> Hello,
>
> Some time ago I sent a Smack namespace documentation and a preliminary
> LSM namespace for RFC. I've been suggested that there shouldn't be a
> separate LSM namespace and that it should live within user namespace.
> And this version does. This is a complete set of patches required for
> Smack namespace.
>
> This was designed with a collaboration of Smack maintainer Casey
> Schaufler.
>
> Smack namespace have been implemented using user namespace hooks added
> by one of the patches. To put some context to it I paste here a
> documentation on what Smack namespace wants to achieve.
>
> LSM hooks themselves are documented in the security.h file inside the
> patch.
>
> The patches are based on:
> https://github.com/cschaufler/smack-next/tree/smack-for-4.2-stacked
>
> The tree with them is avaiable here:
> https://github.com/Havner/smack-namespace/tree/smack-namespace-for-4.2-stacked-v2
>
> Changes from v1:
>  - "kernel/exit.c: make sure current's nsproxy != NULL while checking
>    caps" patch has been dropped
>  - fixed the title of the user_ns operations patch
>
>
> ===================================================================
>
> --- What is a Smack namespace ---
>
> Smack namespace was developed to make it possible for Smack to work
> nicely with Linux containers where there is a full operating system
> with its own init inside the namespace. Such a system working with
> Smack expects to have at least partially working SMACK_MAC_ADMIN to be
> able to change labels of processes and files. This is required to be
> able to securely start applications under the control of Smack and
> manage their access rights.
>
> It was implemented using new LSM hooks added to the user namespace
> that were developed together with Smack namespace.
>
>
> --- Design ideas ---
>
> "Smack namespace" is rather "Smack labels namespace" as not the whole
> MAC is namespaced, only the labels. There is a great analogy between
> Smack labels namespace and the user namespace part that remaps UIDs.
>
> The idea is to create a map of labels for a namespace so the namespace
> is only allowed to use those labels. Smack rules are always the same
> as in the init namespace (limited only by what labels are mapped) and
> cannot be manipulated from the child namespace. The map is actually
> only for labels' names. The underlying structures for labels remain
> the same. The filesystem also stores the "unmapped" labels from the
> init namespace.
>
> Let's say we have those labels in the init namespace:
> label1
> label2
> label3
>
> and those rules:
> label1 label2 rwx
> label1 label3 rwx
> label2 label3 rwx
>
> We create a map for a namespace:
> label1 -> mapped1
> label2 -> mapped2
>
> This means that 'label3' is completely invisible in the namespace. As if
> it didn't exist. All the rules that include it are ignored.
>
> Effectively in the namespace we have only one rule:
> mapped1 mapped2 rwx
>
> Which in reality is:
> label1 label2 rwx
>
> All requests to access an object with a 'label3' will be denied. If it
> ever comes to a situation where 'label3' would have to be printed
> (e.g. reading an exec or mmap label from a file to which we have
> access) then huh sign '?' will be printed instead.
>
> All the operations in the namespace on the remaining labels will have
> to be performed using their mapped names. Things like changing own
> process's label, changing filesystem label. Labels will also be
> printed with their mapped names.
>
> You cannot import new labels in a namespace. Every operation that
> would do so in an init namespace will return an error in the child
> namespace. You cannot assign an unmapped or not existing label to an
> object. You can only operate on labels that have been explicitly
> mapped.
>
>
> --- Capabilities ---
>
> Enabling Smack related capabilities (CAP_MAC_ADMIN and
> CAP_MAC_OVERRIDE) is main goal of Smack namespace, so it can work
> properly in the container. And those capabilities do work to some
> extent. In several places where capabilities are checked compatibility
> with Smack namespace has been introduced. Capabilities are of course
> limited to operate only on mapped labels.
>
> CAP_MAC_OVERRIDE works fully, will allow you to ignore Smack access
> rules, but only between objects that have labels mapped. So in the
> example above having this CAP will allow e.g. label2 to write to
> label1, but will not allow any access to label3.
>
> With CAP_MAC_ADMIN the following operations has been allowed inside
> the namespace:
> - setting and removing xattr on files, including the security.* ones
> - setting process's own label (/proc/self/attr/current)
> - mounting in a privileged Smack mode, which means one can specify
>   additional mount options like: smackfsdef, smackfsfloor etc.
>
> Again this is also allowed only on the mapped labels. Labels on the
> filesystem will be stored in unmapped form so they are preserved
> through reboots.
>
> Such a namespace construct allows e.g. systemd (with Smack support)
> working in a container to assign labels properly to daemons and other
> processes.
>
>
> --- Usage ---
>
> Smack namespace is written using LSM hooks inside user namespace. That
> means it's connected to it.
>
> To create a new Smack namespace you need to unshare() user namespace
> as usual. If that is all you do though, than there is no difference to
> what is now. To activate the Smack namespace you need to fill the
> labels' map. It is in a file /proc/$PID/smack_map.
>
> By default the map is empty and Smack namespaces are inactive (labels
> are taken directly from a parent namespace). It also means that the
> Smack capabilities will be inactive. After you fill the map it starts
> to take effect in the namespace and Smack capabilities (only on mapped
> labels) start to work.
>
> Due to the way Smack works only CAP_MAC_ADMIN from the parent
> namespace (init_user_ns for now, see the "Current limitations" below)
> is allowed to fill the map. That means that an unprivileged user is
> still allowed to create the user namespace but it will not be able to
> fill the labels' map (activate Smack namespace). An administrator
> intervention is required.
>
> The attr_map write format is:
> unmapped_label mapped_label
>
> When reading the file it shows an active map for a namespace the
> process in question is in in the format:
> unmapped_label -> mapped_label
>
> If the smack_map file is empty it means the namespace is not mapped
> and Smack namespace is inactive (no mappings, MAC related capabilities
> behave as they did before, meaning they are active only in
> init_user_ns). For init_user_ns the map will always be empty.
>
> Writing to the map file is not disabled after the first write as it is
> in uid_map. For Smack we have no means to map ranges of labels, hence
> it can really be advantageous to be able to expand the map later
> on. But you can only add to the map. You cannot remove already mapped
> labels. You cannot change the already existing mappings. Also mappings
> has to be 1-1. All requests to create a map where either the unmapped
> or the mapped label already exists in the map will be denied.
>
> setns() with Smack namespace active has an additional check that the
> label of a process that is calling setns() has to be already mapped in
> the target Smack namespace for the call to succeed.
>
>
> --- Special labels ---
>
> Smack is using some special labels that have built-in rules. Things
> like floor '_', dash '^', star '*', etc. Those labels are not
> automatically mapped to the namespace. Moreover, you can choose to map
> a different label from the init namespace to behave e.g. like floor
> inside the namespace.
>
> Let's say we have no rules and those labels in the init namespace:
> _
> floor_to_be
> label
>
> Both 'label' and 'floor_to_be' can read objects with '_'. But they
> have no access rights to each other.
>
> Now let's create a map like this:
> _             ordinary_label
> floor_to_be   _
> label         mapped
>
> Right now label 'mapped' can read label '_' which means that
> effectively inside this namespace label 'label' has gained read access
> to the 'floor_to_be'. The label 'ordinary_label' is exactly it, an
> ordinary label that the built-in rules no longer apply to inside the
> namespace.
>
> To sum up, special labels in the namespace behave the same as in the
> init namespace. Not the original special labels though, but the ones
> we map to specials. This is the only case where a namespace can have
> access rights the init namespace does not have (like the 'label' to
> 'floor_to_be' in the example above).
>
> Of course mappings like these are perfectly legal:
> _   _
> *   *
> ^   ^
>
>
> --- Current limitations ---
>
> The Smack namespace is not hierarchical yet. It is currently not
> possible to fill a smack_map of a nested user namespace (you can still
> create nested user namespace, it will just inherit its parent's map
> and won't have active Smack capabilities). When hierarchy will be
> implemented the process creating another namespace will be allowed to
> map only labels that it has permission to itself (those that it has in
> its own map).
>
> Special files inside the virtual smackfs needs to be reviewed whether
> it's beneficial to have some of their functionality namespaced as well
> (e.g. onlycap, syslog. ambient, etc). This would increase
> CAP_MAC_ADMIN privileges inside the namespace.
>
>
> Lukasz Pawelczyk (7):
>   user_ns: 3 new hooks for user namespace operations
>   smack: extend capability functions and fix 2 checks
>   smack: abstraction layer for 2 common Smack operations
>   smack: misc cleanups in preparation for a namespace patch
>   smack: namespace groundwork
>   smack: namespace implementation
>   smack: documentation for the Smack namespace
>
>  Documentation/security/00-INDEX            |   2 +
>  Documentation/security/Smack-namespace.txt | 231 +++++++++++++
>  MAINTAINERS                                |   1 +
>  fs/proc/base.c                             |  57 +++
>  include/linux/lsm_hooks.h                  |  28 ++
>  include/linux/security.h                   |  23 ++
>  include/linux/user_namespace.h             |   9 +
>  kernel/user.c                              |   3 +
>  kernel/user_namespace.c                    |  18 +
>  security/security.c                        |  28 ++
>  security/smack/Kconfig                     |  12 +
>  security/smack/Makefile                    |   1 +
>  security/smack/smack.h                     | 187 +++++++++-
>  security/smack/smack_access.c              | 191 ++++++++--
>  security/smack/smack_lsm.c                 | 536 ++++++++++++++++++++---------
>  security/smack/smack_ns.c                  | 471 +++++++++++++++++++++++++
>  security/smack/smackfs.c                   | 154 +++++----
>  17 files changed, 1702 insertions(+), 250 deletions(-)
>  create mode 100644 Documentation/security/Smack-namespace.txt
>  create mode 100644 security/smack/smack_ns.c
>

I have reviewed these patches (again!) and don't have
any issues. I see that Mr. Smalley has some insightful
suggestions, and once those are addressed I think that
we should be lined up to sell it to the infrastructure.

Re: [PATCH v2 0/7] Smack namespace

[Eric W. Biederman]

Lukasz Pawelczyk <l.pawelczyk-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> writes:

> Hello,
>
> Some time ago I sent a Smack namespace documentation and a preliminary
> LSM namespace for RFC. I've been suggested that there shouldn't be a
> separate LSM namespace and that it should live within user namespace.
> And this version does. This is a complete set of patches required for
> Smack namespace.
>
> This was designed with a collaboration of Smack maintainer Casey
> Schaufler.
>
> Smack namespace have been implemented using user namespace hooks added
> by one of the patches. To put some context to it I paste here a
> documentation on what Smack namespace wants to achieve.
>
> LSM hooks themselves are documented in the security.h file inside the
> patch.
>
> The patches are based on:
> https://github.com/cschaufler/smack-next/tree/smack-for-4.2-stacked
>
> The tree with them is avaiable here:
> https://github.com/Havner/smack-namespace/tree/smack-namespace-for-4.2-stacked-v2
>
> Changes from v1:
>  - "kernel/exit.c: make sure current's nsproxy != NULL while checking
>    caps" patch has been dropped
>  - fixed the title of the user_ns operations patch

A have not completed a review I don't understand smack well enough to
answer some questions but I don't think I like the approach this patch
takes to get things done.

I am flattered that you are using a mapping as I did with uid map and
gid map.  Unfortunately I do not believe your mapping achieves what my
mapping of uids and gids achieved.

A technical goal is to give people the tools so that a sysadmin can set
up a system, can grant people subids and subgids, and then the user can
proceed to do what they need to do.  In particular there should be
little to no need to keep pestering the system administrator for more
identifiers.

The flip side of that was that the mapping would ensure all of the
existing permissions checks would work as expected, and the checks in
the kernel could be converted without much trouble.

Ranges of ids were choosen because they allow for a lot of possible ways
of using uids and gids in containers, are comparitively easy to
administer, are very fast to use, and don't need large data structures.

With a discreet mapping of labels I have the premonition that we now
have a large data structure that, is not as flexible in to use,
is comparatively slow and appears to require an interaction with the
system administrator for every label you use in a container.

As part of that there is added a void *security pointer in the user
namespace to apparently hang off anything anyone would like to use.
Connected to that are hooks that have failure codes (presumably memory
allocation failures), but the semantics are not clear.  My gut feel is
that I would rather extend struct user_namespace to hold the smack label
mapping table and remove all of the error codes because they would then
be unnecessary.

I am also concerned that several of the operations assume that setns
and the like are normally privileged operations and so require the
ability to perform other privileged operations.  Given that in the right
circumstances setns is not privileged that seems like a semantics
mismatch.

Or in short my gut feel says the semantics of this change are close to
something that would be very useful, but the details make this patchset
far less useful, usable and comprehensible than it should be.

Eric


> ===================================================================
>
> --- What is a Smack namespace ---
>
> Smack namespace was developed to make it possible for Smack to work
> nicely with Linux containers where there is a full operating system
> with its own init inside the namespace. Such a system working with
> Smack expects to have at least partially working SMACK_MAC_ADMIN to be
> able to change labels of processes and files. This is required to be
> able to securely start applications under the control of Smack and
> manage their access rights.
>
> It was implemented using new LSM hooks added to the user namespace
> that were developed together with Smack namespace.
>
>
> --- Design ideas ---
>
> "Smack namespace" is rather "Smack labels namespace" as not the whole
> MAC is namespaced, only the labels. There is a great analogy between
> Smack labels namespace and the user namespace part that remaps UIDs.
>
> The idea is to create a map of labels for a namespace so the namespace
> is only allowed to use those labels. Smack rules are always the same
> as in the init namespace (limited only by what labels are mapped) and
> cannot be manipulated from the child namespace. The map is actually
> only for labels' names. The underlying structures for labels remain
> the same. The filesystem also stores the "unmapped" labels from the
> init namespace.
>
> Let's say we have those labels in the init namespace:
> label1
> label2
> label3
>
> and those rules:
> label1 label2 rwx
> label1 label3 rwx
> label2 label3 rwx
>
> We create a map for a namespace:
> label1 -> mapped1
> label2 -> mapped2
>
> This means that 'label3' is completely invisible in the namespace. As if
> it didn't exist. All the rules that include it are ignored.
>
> Effectively in the namespace we have only one rule:
> mapped1 mapped2 rwx
>
> Which in reality is:
> label1 label2 rwx
>
> All requests to access an object with a 'label3' will be denied. If it
> ever comes to a situation where 'label3' would have to be printed
> (e.g. reading an exec or mmap label from a file to which we have
> access) then huh sign '?' will be printed instead.
>
> All the operations in the namespace on the remaining labels will have
> to be performed using their mapped names. Things like changing own
> process's label, changing filesystem label. Labels will also be
> printed with their mapped names.
>
> You cannot import new labels in a namespace. Every operation that
> would do so in an init namespace will return an error in the child
> namespace. You cannot assign an unmapped or not existing label to an
> object. You can only operate on labels that have been explicitly
> mapped.
>
>
> --- Capabilities ---
>
> Enabling Smack related capabilities (CAP_MAC_ADMIN and
> CAP_MAC_OVERRIDE) is main goal of Smack namespace, so it can work
> properly in the container. And those capabilities do work to some
> extent. In several places where capabilities are checked compatibility
> with Smack namespace has been introduced. Capabilities are of course
> limited to operate only on mapped labels.
>
> CAP_MAC_OVERRIDE works fully, will allow you to ignore Smack access
> rules, but only between objects that have labels mapped. So in the
> example above having this CAP will allow e.g. label2 to write to
> label1, but will not allow any access to label3.
>
> With CAP_MAC_ADMIN the following operations has been allowed inside
> the namespace:
> - setting and removing xattr on files, including the security.* ones
> - setting process's own label (/proc/self/attr/current)
> - mounting in a privileged Smack mode, which means one can specify
>   additional mount options like: smackfsdef, smackfsfloor etc.
>
> Again this is also allowed only on the mapped labels. Labels on the
> filesystem will be stored in unmapped form so they are preserved
> through reboots.
>
> Such a namespace construct allows e.g. systemd (with Smack support)
> working in a container to assign labels properly to daemons and other
> processes.
>
>
> --- Usage ---
>
> Smack namespace is written using LSM hooks inside user namespace. That
> means it's connected to it.
>
> To create a new Smack namespace you need to unshare() user namespace
> as usual. If that is all you do though, than there is no difference to
> what is now. To activate the Smack namespace you need to fill the
> labels' map. It is in a file /proc/$PID/smack_map.
>
> By default the map is empty and Smack namespaces are inactive (labels
> are taken directly from a parent namespace). It also means that the
> Smack capabilities will be inactive. After you fill the map it starts
> to take effect in the namespace and Smack capabilities (only on mapped
> labels) start to work.
>
> Due to the way Smack works only CAP_MAC_ADMIN from the parent
> namespace (init_user_ns for now, see the "Current limitations" below)
> is allowed to fill the map. That means that an unprivileged user is
> still allowed to create the user namespace but it will not be able to
> fill the labels' map (activate Smack namespace). An administrator
> intervention is required.
>
> The attr_map write format is:
> unmapped_label mapped_label
>
> When reading the file it shows an active map for a namespace the
> process in question is in in the format:
> unmapped_label -> mapped_label
>
> If the smack_map file is empty it means the namespace is not mapped
> and Smack namespace is inactive (no mappings, MAC related capabilities
> behave as they did before, meaning they are active only in
> init_user_ns). For init_user_ns the map will always be empty.
>
> Writing to the map file is not disabled after the first write as it is
> in uid_map. For Smack we have no means to map ranges of labels, hence
> it can really be advantageous to be able to expand the map later
> on. But you can only add to the map. You cannot remove already mapped
> labels. You cannot change the already existing mappings. Also mappings
> has to be 1-1. All requests to create a map where either the unmapped
> or the mapped label already exists in the map will be denied.
>
> setns() with Smack namespace active has an additional check that the
> label of a process that is calling setns() has to be already mapped in
> the target Smack namespace for the call to succeed.
>
> --- Special labels ---
>
> Smack is using some special labels that have built-in rules. Things
> like floor '_', dash '^', star '*', etc. Those labels are not
> automatically mapped to the namespace. Moreover, you can choose to map
> a different label from the init namespace to behave e.g. like floor
> inside the namespace.
>
> Let's say we have no rules and those labels in the init namespace:
> _
> floor_to_be
> label
>
> Both 'label' and 'floor_to_be' can read objects with '_'. But they
> have no access rights to each other.
>
> Now let's create a map like this:
> _             ordinary_label
> floor_to_be   _
> label         mapped
>
> Right now label 'mapped' can read label '_' which means that
> effectively inside this namespace label 'label' has gained read access
> to the 'floor_to_be'. The label 'ordinary_label' is exactly it, an
> ordinary label that the built-in rules no longer apply to inside the
> namespace.
>
> To sum up, special labels in the namespace behave the same as in the
> init namespace. Not the original special labels though, but the ones
> we map to specials. This is the only case where a namespace can have
> access rights the init namespace does not have (like the 'label' to
> 'floor_to_be' in the example above).
>
> Of course mappings like these are perfectly legal:
> _   _
> *   *
> ^   ^
>
>
> --- Current limitations ---
>
> The Smack namespace is not hierarchical yet. It is currently not
> possible to fill a smack_map of a nested user namespace (you can still
> create nested user namespace, it will just inherit its parent's map
> and won't have active Smack capabilities). When hierarchy will be
> implemented the process creating another namespace will be allowed to
> map only labels that it has permission to itself (those that it has in
> its own map).

> Special files inside the virtual smackfs needs to be reviewed whether
> it's beneficial to have some of their functionality namespaced as well
> (e.g. onlycap, syslog. ambient, etc). This would increase
> CAP_MAC_ADMIN privileges inside the namespace.
>
>
> Lukasz Pawelczyk (7):
>   user_ns: 3 new hooks for user namespace operations
>   smack: extend capability functions and fix 2 checks
>   smack: abstraction layer for 2 common Smack operations
>   smack: misc cleanups in preparation for a namespace patch
>   smack: namespace groundwork
>   smack: namespace implementation
>   smack: documentation for the Smack namespace
>
>  Documentation/security/00-INDEX            |   2 +
>  Documentation/security/Smack-namespace.txt | 231 +++++++++++++
>  MAINTAINERS                                |   1 +
>  fs/proc/base.c                             |  57 +++
>  include/linux/lsm_hooks.h                  |  28 ++
>  include/linux/security.h                   |  23 ++
>  include/linux/user_namespace.h             |   9 +
>  kernel/user.c                              |   3 +
>  kernel/user_namespace.c                    |  18 +
>  security/security.c                        |  28 ++
>  security/smack/Kconfig                     |  12 +
>  security/smack/Makefile                    |   1 +
>  security/smack/smack.h                     | 187 +++++++++-
>  security/smack/smack_access.c              | 191 ++++++++--
>  security/smack/smack_lsm.c                 | 536 ++++++++++++++++++++---------
>  security/smack/smack_ns.c                  | 471 +++++++++++++++++++++++++
>  security/smack/smackfs.c                   | 154 +++++----
>  17 files changed, 1702 insertions(+), 250 deletions(-)
>  create mode 100644 Documentation/security/Smack-namespace.txt
>  create mode 100644 security/smack/smack_ns.c

Re: [PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

On wto, 2015-05-26 at 22:13 -0500, Eric W. Biederman wrote:
> Lukasz Pawelczyk <l.pawelczyk@samsung.com> writes:
> 
> > Hello,
> >
> > Some time ago I sent a Smack namespace documentation and a preliminary
> > LSM namespace for RFC. I've been suggested that there shouldn't be a
> > separate LSM namespace and that it should live within user namespace.
> > And this version does. This is a complete set of patches required for
> > Smack namespace.
> >
> > This was designed with a collaboration of Smack maintainer Casey
> > Schaufler.
> >
> > Smack namespace have been implemented using user namespace hooks added
> > by one of the patches. To put some context to it I paste here a
> > documentation on what Smack namespace wants to achieve.
> >
> > LSM hooks themselves are documented in the security.h file inside the
> > patch.
> >
> > The patches are based on:
> > https://github.com/cschaufler/smack-next/tree/smack-for-4.2-stacked
> >
> > The tree with them is avaiable here:
> > https://github.com/Havner/smack-namespace/tree/smack-namespace-for-4.2-stacked-v2
> >
> > Changes from v1:
> >  - "kernel/exit.c: make sure current's nsproxy != NULL while checking
> >    caps" patch has been dropped
> >  - fixed the title of the user_ns operations patch
> 
> A have not completed a review I don't understand smack well enough to
> answer some questions but I don't think I like the approach this patch
> takes to get things done.
> 
> I am flattered that you are using a mapping as I did with uid map and
> gid map.  Unfortunately I do not believe your mapping achieves what my
> mapping of uids and gids achieved.
> 
> A technical goal is to give people the tools so that a sysadmin can set
> up a system, can grant people subids and subgids, and then the user can
> proceed to do what they need to do. 

This is exactly the case with Smack namespace.


> In particular there should be
> little to no need to keep pestering the system administrator for more
> identifiers.

This all depends on the use case. When you create a new namespace for a
particular purpose you could know what labels will be required there and
map them upfront. Adding new mappings is for a use case that a container
might have new software installed that requires new labels for it. You
don't create/import new labels on a normal basis all the time.


> The flip side of that was that the mapping would ensure all of the
> existing permissions checks would work as expected, and the checks in
> the kernel could be converted without much trouble.

Again, this is exactly the case with Smack namespace. There are
additional checks in place of course, but the rules are clear about
how that works.


> Ranges of ids were choosen because they allow for a lot of possible ways
> of using uids and gids in containers, are comparitively easy to
> administer, are very fast to use, and don't need large data structures.

This is Smack specific. The same way we could compare Smack with DAC
(even without talking about namespaces). Every new UID is just it, a
number. Every new label requires allocation and adds to the list.

I had an idea about mapping ranges of labels for a container by using
prefixes but this was dropped by Casey. Labels (with an exception of the
built-in ones) should not have any special meaning. This is Smack
design.

About performance, as it was originally with Smack. The list of labels
was a simple list. When the performance was not enough hashing was
added. I'd take the same approach here. If some use cases will require
so many mappings that this becomes a problem we will deal with it. I
don't want to complicate the patches now and I this was Casey's opinion
as well.


> With a discreet mapping of labels I have the premonition that we now
> have a large data structure that, is not as flexible in to use,
> is comparatively slow and appears to require an interaction with the
> system administrator for every label you use in a container.

Again, DAC vs Smack philosophy. The same way a new label appears in init
namespace (e.g. with a file/inode). Without a new rule you won't have an
access to it. This requires administrator intervention as well. This is
MAC after all.


> As part of that there is added a void *security pointer in the user
> namespace to apparently hang off anything anyone would like to use.
> Connected to that are hooks that have failure codes (presumably memory
> allocation failures), but the semantics are not clear.  My gut feel is
> that I would rather extend struct user_namespace to hold the smack label
> mapping table and remove all of the error codes because they would then
> be unnecessary.

How is this different then filling a void *security pointer for other
kernel objects (tasks, indodes, ipc, etc). The allocations can fail as
well. I don't see how the semantics are different here.

So you would have me a Smack generic pointer in user_namespace without
any LSM abstraction? How does that cope with LSM philosophy and recently
introduced (initial) LSM stacking?


> I am also concerned that several of the operations assume that setns
> and the like are normally privileged operations and so require the
> ability to perform other privileged operations.  Given that in the right
> circumstances setns is not privileged that seems like a semantics
> mismatch.

Sorry, I don't exactly know what you mean. setns remains unprivileged
operation here. The only limit is to refuse setns when adding a process
to a container would break Smack namespace rules. In theory this
limitation could be removed (I think), because a process with an
unmapped label would not be able to do anything in the namespace. This
is mostly for convenience.


> Or in short my gut feel says the semantics of this change are close to
> something that would be very useful, but the details make this patchset
> far less useful, usable and comprehensible than it should be.

This isn't much to go on for me unfortunately.
Anyway, thank you for your insight, and taking the time.


> 
> Eric
> 
> 
> > ===================================================================
> >
> > --- What is a Smack namespace ---
> >
> > Smack namespace was developed to make it possible for Smack to work
> > nicely with Linux containers where there is a full operating system
> > with its own init inside the namespace. Such a system working with
> > Smack expects to have at least partially working SMACK_MAC_ADMIN to be
> > able to change labels of processes and files. This is required to be
> > able to securely start applications under the control of Smack and
> > manage their access rights.
> >
> > It was implemented using new LSM hooks added to the user namespace
> > that were developed together with Smack namespace.
> >
> >
> > --- Design ideas ---
> >
> > "Smack namespace" is rather "Smack labels namespace" as not the whole
> > MAC is namespaced, only the labels. There is a great analogy between
> > Smack labels namespace and the user namespace part that remaps UIDs.
> >
> > The idea is to create a map of labels for a namespace so the namespace
> > is only allowed to use those labels. Smack rules are always the same
> > as in the init namespace (limited only by what labels are mapped) and
> > cannot be manipulated from the child namespace. The map is actually
> > only for labels' names. The underlying structures for labels remain
> > the same. The filesystem also stores the "unmapped" labels from the
> > init namespace.
> >
> > Let's say we have those labels in the init namespace:
> > label1
> > label2
> > label3
> >
> > and those rules:
> > label1 label2 rwx
> > label1 label3 rwx
> > label2 label3 rwx
> >
> > We create a map for a namespace:
> > label1 -> mapped1
> > label2 -> mapped2
> >
> > This means that 'label3' is completely invisible in the namespace. As if
> > it didn't exist. All the rules that include it are ignored.
> >
> > Effectively in the namespace we have only one rule:
> > mapped1 mapped2 rwx
> >
> > Which in reality is:
> > label1 label2 rwx
> >
> > All requests to access an object with a 'label3' will be denied. If it
> > ever comes to a situation where 'label3' would have to be printed
> > (e.g. reading an exec or mmap label from a file to which we have
> > access) then huh sign '?' will be printed instead.
> >
> > All the operations in the namespace on the remaining labels will have
> > to be performed using their mapped names. Things like changing own
> > process's label, changing filesystem label. Labels will also be
> > printed with their mapped names.
> >
> > You cannot import new labels in a namespace. Every operation that
> > would do so in an init namespace will return an error in the child
> > namespace. You cannot assign an unmapped or not existing label to an
> > object. You can only operate on labels that have been explicitly
> > mapped.
> >
> >
> > --- Capabilities ---
> >
> > Enabling Smack related capabilities (CAP_MAC_ADMIN and
> > CAP_MAC_OVERRIDE) is main goal of Smack namespace, so it can work
> > properly in the container. And those capabilities do work to some
> > extent. In several places where capabilities are checked compatibility
> > with Smack namespace has been introduced. Capabilities are of course
> > limited to operate only on mapped labels.
> >
> > CAP_MAC_OVERRIDE works fully, will allow you to ignore Smack access
> > rules, but only between objects that have labels mapped. So in the
> > example above having this CAP will allow e.g. label2 to write to
> > label1, but will not allow any access to label3.
> >
> > With CAP_MAC_ADMIN the following operations has been allowed inside
> > the namespace:
> > - setting and removing xattr on files, including the security.* ones
> > - setting process's own label (/proc/self/attr/current)
> > - mounting in a privileged Smack mode, which means one can specify
> >   additional mount options like: smackfsdef, smackfsfloor etc.
> >
> > Again this is also allowed only on the mapped labels. Labels on the
> > filesystem will be stored in unmapped form so they are preserved
> > through reboots.
> >
> > Such a namespace construct allows e.g. systemd (with Smack support)
> > working in a container to assign labels properly to daemons and other
> > processes.
> >
> >
> > --- Usage ---
> >
> > Smack namespace is written using LSM hooks inside user namespace. That
> > means it's connected to it.
> >
> > To create a new Smack namespace you need to unshare() user namespace
> > as usual. If that is all you do though, than there is no difference to
> > what is now. To activate the Smack namespace you need to fill the
> > labels' map. It is in a file /proc/$PID/smack_map.
> >
> > By default the map is empty and Smack namespaces are inactive (labels
> > are taken directly from a parent namespace). It also means that the
> > Smack capabilities will be inactive. After you fill the map it starts
> > to take effect in the namespace and Smack capabilities (only on mapped
> > labels) start to work.
> >
> > Due to the way Smack works only CAP_MAC_ADMIN from the parent
> > namespace (init_user_ns for now, see the "Current limitations" below)
> > is allowed to fill the map. That means that an unprivileged user is
> > still allowed to create the user namespace but it will not be able to
> > fill the labels' map (activate Smack namespace). An administrator
> > intervention is required.
> >
> > The attr_map write format is:
> > unmapped_label mapped_label
> >
> > When reading the file it shows an active map for a namespace the
> > process in question is in in the format:
> > unmapped_label -> mapped_label
> >
> > If the smack_map file is empty it means the namespace is not mapped
> > and Smack namespace is inactive (no mappings, MAC related capabilities
> > behave as they did before, meaning they are active only in
> > init_user_ns). For init_user_ns the map will always be empty.
> >
> > Writing to the map file is not disabled after the first write as it is
> > in uid_map. For Smack we have no means to map ranges of labels, hence
> > it can really be advantageous to be able to expand the map later
> > on. But you can only add to the map. You cannot remove already mapped
> > labels. You cannot change the already existing mappings. Also mappings
> > has to be 1-1. All requests to create a map where either the unmapped
> > or the mapped label already exists in the map will be denied.
> >
> > setns() with Smack namespace active has an additional check that the
> > label of a process that is calling setns() has to be already mapped in
> > the target Smack namespace for the call to succeed.
> >
> > --- Special labels ---
> >
> > Smack is using some special labels that have built-in rules. Things
> > like floor '_', dash '^', star '*', etc. Those labels are not
> > automatically mapped to the namespace. Moreover, you can choose to map
> > a different label from the init namespace to behave e.g. like floor
> > inside the namespace.
> >
> > Let's say we have no rules and those labels in the init namespace:
> > _
> > floor_to_be
> > label
> >
> > Both 'label' and 'floor_to_be' can read objects with '_'. But they
> > have no access rights to each other.
> >
> > Now let's create a map like this:
> > _             ordinary_label
> > floor_to_be   _
> > label         mapped
> >
> > Right now label 'mapped' can read label '_' which means that
> > effectively inside this namespace label 'label' has gained read access
> > to the 'floor_to_be'. The label 'ordinary_label' is exactly it, an
> > ordinary label that the built-in rules no longer apply to inside the
> > namespace.
> >
> > To sum up, special labels in the namespace behave the same as in the
> > init namespace. Not the original special labels though, but the ones
> > we map to specials. This is the only case where a namespace can have
> > access rights the init namespace does not have (like the 'label' to
> > 'floor_to_be' in the example above).
> >
> > Of course mappings like these are perfectly legal:
> > _   _
> > *   *
> > ^   ^
> >
> >
> > --- Current limitations ---
> >
> > The Smack namespace is not hierarchical yet. It is currently not
> > possible to fill a smack_map of a nested user namespace (you can still
> > create nested user namespace, it will just inherit its parent's map
> > and won't have active Smack capabilities). When hierarchy will be
> > implemented the process creating another namespace will be allowed to
> > map only labels that it has permission to itself (those that it has in
> > its own map).
> 
> > Special files inside the virtual smackfs needs to be reviewed whether
> > it's beneficial to have some of their functionality namespaced as well
> > (e.g. onlycap, syslog. ambient, etc). This would increase
> > CAP_MAC_ADMIN privileges inside the namespace.
> >
> >
> > Lukasz Pawelczyk (7):
> >   user_ns: 3 new hooks for user namespace operations
> >   smack: extend capability functions and fix 2 checks
> >   smack: abstraction layer for 2 common Smack operations
> >   smack: misc cleanups in preparation for a namespace patch
> >   smack: namespace groundwork
> >   smack: namespace implementation
> >   smack: documentation for the Smack namespace
> >
> >  Documentation/security/00-INDEX            |   2 +
> >  Documentation/security/Smack-namespace.txt | 231 +++++++++++++
> >  MAINTAINERS                                |   1 +
> >  fs/proc/base.c                             |  57 +++
> >  include/linux/lsm_hooks.h                  |  28 ++
> >  include/linux/security.h                   |  23 ++
> >  include/linux/user_namespace.h             |   9 +
> >  kernel/user.c                              |   3 +
> >  kernel/user_namespace.c                    |  18 +
> >  security/security.c                        |  28 ++
> >  security/smack/Kconfig                     |  12 +
> >  security/smack/Makefile                    |   1 +
> >  security/smack/smack.h                     | 187 +++++++++-
> >  security/smack/smack_access.c              | 191 ++++++++--
> >  security/smack/smack_lsm.c                 | 536 ++++++++++++++++++++---------
> >  security/smack/smack_ns.c                  | 471 +++++++++++++++++++++++++
> >  security/smack/smackfs.c                   | 154 +++++----
> >  17 files changed, 1702 insertions(+), 250 deletions(-)
> >  create mode 100644 Documentation/security/Smack-namespace.txt
> >  create mode 100644 security/smack/smack_ns.c

-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics



-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 0/7] Smack namespace

[Eric W. Biederman]

Lukasz Pawelczyk <l.pawelczyk@samsung.com> writes:

> On wto, 2015-05-26 at 22:13 -0500, Eric W. Biederman wrote:
>> Lukasz Pawelczyk <l.pawelczyk@samsung.com> writes:
>> 
>> > Hello,
>> >
>> > Some time ago I sent a Smack namespace documentation and a preliminary
>> > LSM namespace for RFC. I've been suggested that there shouldn't be a
>> > separate LSM namespace and that it should live within user namespace.
>> > And this version does. This is a complete set of patches required for
>> > Smack namespace.
>> >
>> > This was designed with a collaboration of Smack maintainer Casey
>> > Schaufler.
>> >
>> > Smack namespace have been implemented using user namespace hooks added
>> > by one of the patches. To put some context to it I paste here a
>> > documentation on what Smack namespace wants to achieve.
>> >
>> > LSM hooks themselves are documented in the security.h file inside the
>> > patch.
>> >
>> > The patches are based on:
>> > https://github.com/cschaufler/smack-next/tree/smack-for-4.2-stacked
>> >
>> > The tree with them is avaiable here:
>> > https://github.com/Havner/smack-namespace/tree/smack-namespace-for-4.2-stacked-v2
>> >
>> > Changes from v1:
>> >  - "kernel/exit.c: make sure current's nsproxy != NULL while checking
>> >    caps" patch has been dropped
>> >  - fixed the title of the user_ns operations patch
>> 
>> A have not completed a review I don't understand smack well enough to
>> answer some questions but I don't think I like the approach this patch
>> takes to get things done.
>> 
>> I am flattered that you are using a mapping as I did with uid map and
>> gid map.  Unfortunately I do not believe your mapping achieves what my
>> mapping of uids and gids achieved.
>> 
>> A technical goal is to give people the tools so that a sysadmin can set
>> up a system, can grant people subids and subgids, and then the user can
>> proceed to do what they need to do. 
>
> This is exactly the case with Smack namespace.
>
>
>> In particular there should be
>> little to no need to keep pestering the system administrator for more
>> identifiers.
>
> This all depends on the use case. When you create a new namespace for a
> particular purpose you could know what labels will be required there and
> map them upfront. Adding new mappings is for a use case that a container
> might have new software installed that requires new labels for it. You
> don't create/import new labels on a normal basis all the time.

Good.

>> The flip side of that was that the mapping would ensure all of the
>> existing permissions checks would work as expected, and the checks in
>> the kernel could be converted without much trouble.
>
> Again, this is exactly the case with Smack namespace. There are
> additional checks in place of course, but the rules are clear about
> how that works.
>
>
>> Ranges of ids were choosen because they allow for a lot of possible ways
>> of using uids and gids in containers, are comparitively easy to
>> administer, are very fast to use, and don't need large data structures.
>
> This is Smack specific. The same way we could compare Smack with DAC
> (even without talking about namespaces). Every new UID is just it, a
> number. Every new label requires allocation and adds to the list.
>
> I had an idea about mapping ranges of labels for a container by using
> prefixes but this was dropped by Casey. Labels (with an exception of the
> built-in ones) should not have any special meaning. This is Smack
> design.

Maybe.  All I care about is the resources for user namespaces remain
something that the administrator can set up (before any containers
exist) a set of resources (uid, gids, labels?) that an individual user
can use and then that user can set up containers as they desire.

That is the property that the administration of the container is fully
delegated to the whoever creates the container.

> About performance, as it was originally with Smack. The list of labels
> was a simple list. When the performance was not enough hashing was
> added. I'd take the same approach here. If some use cases will require
> so many mappings that this becomes a problem we will deal with it. I
> don't want to complicate the patches now and I this was Casey's opinion
> as well.

Occassionally performance implications are sufficiently profound that
it impacts your userspace API, and thus all future maintenance.  How
labels are managed and mapped into a container appears to be one such
issue.  So unfortunately it does not appear to shove performance
questions off until later.

And actually it is much more about managability rather than raw
performance.

What I know is that the human factors of how these identifiers are
assigned and managed is important.  Especially as they are persistent on
disk and likely need to be kept consistent between multiple different
machines.

A range of uids, a prefix on a label, those kinds of things are simple
and easy to understand and make sense of.  The rule is simple enough I
can track it in my head and I don't need to keep going back and looking
at configuration files.   Discrete unrelated assignment of values
(unless the set of values is very small) does not work that way and
makes things less managable.

Which leads to my observation that if the mapping rule is simple enough
I can keep track of it in my head I can put a small array in struct
user_namespace to implement that rule.

>> With a discreet mapping of labels I have the premonition that we now
>> have a large data structure that, is not as flexible in to use,
>> is comparatively slow and appears to require an interaction with the
>> system administrator for every label you use in a container.
>
> Again, DAC vs Smack philosophy. The same way a new label appears in init
> namespace (e.g. with a file/inode). Without a new rule you won't have an
> access to it. This requires administrator intervention as well. This is
> MAC after all.

If it does not work with how user namespaces are designed to be used
this approach gets my nack.  I will not accept an approach that requires
asking a system administrator permission for every little change.  That
fundamentally is what the user namespace gets away from.

If on the other hand the sysadmin interaction becomes here are N labels
do what you need to with them.  Where N is sufficiently large that most
users can be given those N labels and then users don't have to ask about
it I can live with that.

>> As part of that there is added a void *security pointer in the user
>> namespace to apparently hang off anything anyone would like to use.
>> Connected to that are hooks that have failure codes (presumably memory
>> allocation failures), but the semantics are not clear.  My gut feel is
>> that I would rather extend struct user_namespace to hold the smack label
>> mapping table and remove all of the error codes because they would then
>> be unnecessary.
>
> How is this different then filling a void *security pointer for other
> kernel objects (tasks, indodes, ipc, etc). The allocations can fail as
> well. I don't see how the semantics are different here.
>
> So you would have me a Smack generic pointer in user_namespace without
> any LSM abstraction? How does that cope with LSM philosophy and recently
> introduced (initial) LSM stacking?

I would have an smack specific array of mapped labels (probably in a
union).

I am not an LSM guy and to me tell the only important LSM philosophy is
provide a way for the various people who want to odd things with
security to each have a place at the table so they don't fight.

What you are proposing is something different from core LSM activities.

I have a hard time working with ``security'' code in the kernel as
almost invariably it is some of the worst code in the core kernel.
There are likely a lot of reasons for that but one reason that stands
out to me is the LSM interface seems to relegate the ``security'' code
to second class status.

We have merged the security modules now and we no longer support
loadable modules so I think some of the original design assumptions can
be reexamined.  If we will change anything upon reexamination I don't
know and I am not looking for any great whole sale change.  But I do
intend to look at LSM related changes to the code I maintain under the
same spot light and under the same criteria as I look at any other
changes.

i.e. I can't ignore what the LSMs do during code maintenance so I won't
ignore what the LSMs do or want to do when adding LSM hooks.

>> I am also concerned that several of the operations assume that setns
>> and the like are normally privileged operations and so require the
>> ability to perform other privileged operations.  Given that in the right
>> circumstances setns is not privileged that seems like a semantics
>> mismatch.
>
> Sorry, I don't exactly know what you mean. setns remains unprivileged
> operation here. The only limit is to refuse setns when adding a process
> to a container would break Smack namespace rules. In theory this
> limitation could be removed (I think), because a process with an
> unmapped label would not be able to do anything in the namespace. This
> is mostly for convenience.

The rule may make sense but because of it it sounds like in practice you
may actually have to be root to enter a container.  

>> Or in short my gut feel says the semantics of this change are close to
>> something that would be very useful, but the details make this patchset
>> far less useful, usable and comprehensible than it should be.
>
> This isn't much to go on for me unfortunately.
> Anyway, thank you for your insight, and taking the time.

Eric

Re: [PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

On śro, 2015-05-27 at 10:12 -0500, Eric W. Biederman wrote:
> Lukasz Pawelczyk <l.pawelczyk@samsung.com> writes:
> > On wto, 2015-05-26 at 22:13 -0500, Eric W. Biederman wrote:
> >> In particular there should be
> >> little to no need to keep pestering the system administrator for more
> >> identifiers.
> >
> > This all depends on the use case. When you create a new namespace for a
> > particular purpose you could know what labels will be required there and
> > map them upfront. Adding new mappings is for a use case that a container
> > might have new software installed that requires new labels for it. You
> > don't create/import new labels on a normal basis all the time.
> 
> Good.
> 
> >> The flip side of that was that the mapping would ensure all of the
> >> existing permissions checks would work as expected, and the checks in
> >> the kernel could be converted without much trouble.
> >
> > Again, this is exactly the case with Smack namespace. There are
> > additional checks in place of course, but the rules are clear about
> > how that works.
> >
> >
> >> Ranges of ids were choosen because they allow for a lot of possible ways
> >> of using uids and gids in containers, are comparitively easy to
> >> administer, are very fast to use, and don't need large data structures.
> >
> > This is Smack specific. The same way we could compare Smack with DAC
> > (even without talking about namespaces). Every new UID is just it, a
> > number. Every new label requires allocation and adds to the list.
> >
> > I had an idea about mapping ranges of labels for a container by using
> > prefixes but this was dropped by Casey. Labels (with an exception of the
> > built-in ones) should not have any special meaning. This is Smack
> > design.
> 
> Maybe.  All I care about is the resources for user namespaces remain
> something that the administrator can set up (before any containers
> exist) a set of resources (uid, gids, labels?) that an individual user
> can use and then that user can set up containers as they desire.
> 
> That is the property that the administration of the container is fully
> delegated to the whoever creates the container.

You can do that the same way as in user namespace.

You are allowed to add mappings later, but e.g. if you have a hermetic
container you don't have to. This is not required for a Smack namespace
to work. It's purely optional. You can map a set of labels and forget
about it. The namespace will not be able to import/create a new ones but
it will work just fine.


> > About performance, as it was originally with Smack. The list of labels
> > was a simple list. When the performance was not enough hashing was
> > added. I'd take the same approach here. If some use cases will require
> > so many mappings that this becomes a problem we will deal with it. I
> > don't want to complicate the patches now and I this was Casey's opinion
> > as well.
> 
> Occassionally performance implications are sufficiently profound that
> it impacts your userspace API, and thus all future maintenance.  How
> labels are managed and mapped into a container appears to be one such
> issue.  So unfortunately it does not appear to shove performance
> questions off until later.

In this case the only "public" kernel API are user_ns hooks that are
orthogonal to the Smack internals, so I don't really see how is that a
case.

I was also asked by Stephen Smalley to make the label map a generic file
in /proc/$PID/attr/ so it will also be up to the LSM to decide how this
file is treated. It will be abstracted by getprocattr/setprocattr hooks
or something similar.


> And actually it is much more about managability rather than raw
> performance.
> 
> What I know is that the human factors of how these identifiers are
> assigned and managed is important.  Especially as they are persistent on
> disk and likely need to be kept consistent between multiple different
> machines.
> 
> A range of uids, a prefix on a label, those kinds of things are simple
> and easy to understand and make sense of.  The rule is simple enough I
> can track it in my head and I don't need to keep going back and looking
> at configuration files.   Discrete unrelated assignment of values
> (unless the set of values is very small) does not work that way and
> makes things less managable.

Like I said, this is Smack design (fortunately or not). I don't really
see how that could be different here. We might argue why Smack uses
strings instead of numbers. But by design those strings should bear no
special meaning and Casey stressed this on several occasions.

Nobody prevents you from doing prefixes yourself though:
C1_label1 -> label1
C1_label2 -> label2
etc..


> Which leads to my observation that if the mapping rule is simple enough
> I can keep track of it in my head I can put a small array in struct
> user_namespace to implement that rule.

Even though you can only have 5 mappings in user_ns you could in
principle map the UIDs in a way that would be confusing. The 5 mappings
mitigate that significantly of course, but numbers are easier to deal
with than strings. It's just the way it is.


> >> With a discreet mapping of labels I have the premonition that we now
> >> have a large data structure that, is not as flexible in to use,
> >> is comparatively slow and appears to require an interaction with the
> >> system administrator for every label you use in a container.
> >
> > Again, DAC vs Smack philosophy. The same way a new label appears in init
> > namespace (e.g. with a file/inode). Without a new rule you won't have an
> > access to it. This requires administrator intervention as well. This is
> > MAC after all.
> 
> If it does not work with how user namespaces are designed to be used
> this approach gets my nack.  I will not accept an approach that requires
> asking a system administrator permission for every little change.  That
> fundamentally is what the user namespace gets away from.
>
> If on the other hand the sysadmin interaction becomes here are N labels
> do what you need to with them.  Where N is sufficiently large that most
> users can be given those N labels and then users don't have to ask about
> it I can live with that.

This works here as I described earlier in this email.


> >> As part of that there is added a void *security pointer in the user
> >> namespace to apparently hang off anything anyone would like to use.
> >> Connected to that are hooks that have failure codes (presumably memory
> >> allocation failures), but the semantics are not clear.  My gut feel is
> >> that I would rather extend struct user_namespace to hold the smack label
> >> mapping table and remove all of the error codes because they would then
> >> be unnecessary.
> >
> > How is this different then filling a void *security pointer for other
> > kernel objects (tasks, indodes, ipc, etc). The allocations can fail as
> > well. I don't see how the semantics are different here.
> >
> > So you would have me a Smack generic pointer in user_namespace without
> > any LSM abstraction? How does that cope with LSM philosophy and recently
> > introduced (initial) LSM stacking?
> 
> I would have an smack specific array of mapped labels (probably in a
> union).
> 
> I am not an LSM guy and to me tell the only important LSM philosophy is
> provide a way for the various people who want to odd things with
> security to each have a place at the table so they don't fight.
> 
> What you are proposing is something different from core LSM activities.

I think this actually is very much in line with LSM activities. Every
object with a security context gets an opaque pointer that LSM
interprets as it wants. And does whatever it wants with it to make
security decisions.


> I have a hard time working with ``security'' code in the kernel as
> almost invariably it is some of the worst code in the core kernel.
> There are likely a lot of reasons for that but one reason that stands
> out to me is the LSM interface seems to relegate the ``security'' code
> to second class status.
> 
> We have merged the security modules now and we no longer support
> loadable modules so I think some of the original design assumptions can
> be reexamined. 

This is new to me and recently I have heard quite the opposite in regard
to the newly introduced LSM stacking code. I'm not aware that
out-of-tree modules should not be supported.

People do have and use out-of-tree LSM modules. Not having an opaque
pointer blocks them from using those LSM hooks.

And recent stacking changes try to make this infrastructure even more
generic, by proving stacked security pointers (hooks should already be
stacked in 4.2 afaik):

http://www.spinics.net/linux/fedora/linux-security-module/msg21608.html


>  If we will change anything upon reexamination I don't
> know and I am not looking for any great whole sale change.  But I do
> intend to look at LSM related changes to the code I maintain under the
> same spot light and under the same criteria as I look at any other
> changes.
> 
> i.e. I can't ignore what the LSMs do during code maintenance so I won't
> ignore what the LSMs do or want to do when adding LSM hooks.
> 
> >> I am also concerned that several of the operations assume that setns
> >> and the like are normally privileged operations and so require the
> >> ability to perform other privileged operations.  Given that in the right
> >> circumstances setns is not privileged that seems like a semantics
> >> mismatch.
> >
> > Sorry, I don't exactly know what you mean. setns remains unprivileged
> > operation here. The only limit is to refuse setns when adding a process
> > to a container would break Smack namespace rules. In theory this
> > limitation could be removed (I think), because a process with an
> > unmapped label would not be able to do anything in the namespace. This
> > is mostly for convenience.
> 
> The rule may make sense but because of it it sounds like in practice you
> may actually have to be root to enter a container.  

In this particular case UID is irrelevant. You'll either be allowed or
not. Depending on Smack rules.

If the check would be removed UID would still be irrelevant. You'd
always be allowed (as far as Smack is concerned of course) but depending
on Smack rules the process would be usable or not (not able to access
anything, even itself).

I think you can't try to compare apples and oranges. Smack security
model, or any MAC for that matter will not be analogous to DAC. Being
root can be completely irrelevant for an LSM module. And it's completely
its own decision.

If a hook is added for some syscall a module might have its arbitrary
rules for allowing it or not. I don't see anything awkward here. And
honestly I think that having a hook for setns where it might be
allowed/refused could be beneficial to other LSM modules.

The hook itself doesn't define any decision/model. A module does.


As a side note: I do realize that having security context in user
namespace makes it kinda more of a security namespace (DAC, MAC, CAPS,
etc).

Initially I made a whole separate namespace for LSM. You told me this
was a strange decision and I agree now.

This extends user namespace a little and I don't feel this is bad. Even
now user_ns is not a part of nsproxy, but cred. It's created first and
referenced from all the other namespaces. It doesn't only map UIDs. It
also gives capabilities a context. So in the same way it could hold MAC
security context for MAC related decisions that don't necessarily align
with DAC (that's what MAC is for after all).



-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

On wto, 2015-05-26 at 18:04 -0700, Casey Schaufler wrote:
> On 5/25/2015 5:32 AM, Lukasz Pawelczyk wrote:
> > Hello,
> >
> > Some time ago I sent a Smack namespace documentation and a preliminary
> > LSM namespace for RFC. I've been suggested that there shouldn't be a
> > separate LSM namespace and that it should live within user namespace.
> > And this version does. This is a complete set of patches required for
> > Smack namespace.
> >
> > This was designed with a collaboration of Smack maintainer Casey
> > Schaufler.
> >
> 
> I have reviewed these patches (again!) and don't have
> any issues. I see that Mr. Smalley has some insightful
> suggestions, and once those are addressed I think that
> we should be lined up to sell it to the infrastructure.


Thank you.

Can I add
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>

to those 7 the patches?


-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 0/7] Smack namespace

[Casey Schaufler]

On 5/27/2015 2:29 AM, Lukasz Pawelczyk wrote:
> On wto, 2015-05-26 at 18:04 -0700, Casey Schaufler wrote:
>> On 5/25/2015 5:32 AM, Lukasz Pawelczyk wrote:
>>> Hello,
>>>
>>> Some time ago I sent a Smack namespace documentation and a preliminary
>>> LSM namespace for RFC. I've been suggested that there shouldn't be a
>>> separate LSM namespace and that it should live within user namespace.
>>> And this version does. This is a complete set of patches required for
>>> Smack namespace.
>>>
>>> This was designed with a collaboration of Smack maintainer Casey
>>> Schaufler.
>>>
>> I have reviewed these patches (again!) and don't have
>> any issues. I see that Mr. Smalley has some insightful
>> suggestions, and once those are addressed I think that
>> we should be lined up to sell it to the infrastructure.
>
> Thank you.
>
> Can I add
> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
>
> to those 7 the patches?

Yes, but please be sure to address the issues raised by Stephen and Eric.

Re: [PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

Hi,

Thanks for taking the interest and commenting on this.
Replies below.


On wto, 2015-05-26 at 10:35 -0400, Stephen Smalley wrote:
> On 05/25/2015 08:32 AM, Lukasz Pawelczyk wrote:
> > --- Design ideas ---
> > 
> > "Smack namespace" is rather "Smack labels namespace" as not the whole
> > MAC is namespaced, only the labels. There is a great analogy between
> > Smack labels namespace and the user namespace part that remaps UIDs.
> > 
> > The idea is to create a map of labels for a namespace so the namespace
> > is only allowed to use those labels. Smack rules are always the same
> > as in the init namespace (limited only by what labels are mapped) and
> > cannot be manipulated from the child namespace. The map is actually
> > only for labels' names. The underlying structures for labels remain
> > the same. The filesystem also stores the "unmapped" labels from the
> > init namespace.
> 
> How do you achieve that without introducing additional hooks or
> reworking the current hooks in the setxattr code path?  At present, the
> security module is allowed to rewrite getxattr requests on the
> security.* namespace but it isn't allowed to do that for setxattr, so if
> the process invokes setxattr with a mapped label, then it will be the
> mapped label that gets passed to the filesystem implementation, not the
> unmapped label.  The security module may internally store it in unmapped
> form and may even return that upon getxattr() calls, but if you then
> reboot the system and later fetch from the filesystem, it will get the
> mapped label value.

I call the inode operation by hand in the post_setxattr.

The label will effectively be set twice, which is not ideal, but there
is no other option right now without reworking the hooks as you said.

This shouldn't really be a problem because the Smack operations will not
use the filesystem label (even when it's set incorrectly for a moment)
but an already initialized smack_known structure for this inode that has
all the values filled in properly.

The only attack vector I can think of is hard rebooting the machine in a
way that mapped label is really saved in the filesystem before the
unmapped will have a chance. Should I be worried about that? This sounds
a little unreal.


@@ -1163,12 +1214,24 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
                skpp = &isp->smk_mmap;
 
        if (skpp) {
-               skp = smk_get_label(value, size, true);
+               skp = smk_get_label(value, size, true, ns);
 
                if (!IS_ERR(skp))
                        *skpp = skp;
                else
                        *skpp = &smack_known_invalid;
+
+               /*
+                * The label we get above might be a different than the one
+                * kernel has already set before calling this function.
+                * Be consistent and set the final value in the filesystem.
+                * The cases for this are errors and labels being used
+                * in a namespace where we want to store an unmapped
+                * value in the filesystem.
+                */
+               dentry->d_inode->i_op->setxattr(dentry, name,
+                                               (*skpp)->smk_known,
+                                               size, flags);
        }
 }
 


> 
> > --- Usage ---
> > 
> > Smack namespace is written using LSM hooks inside user namespace. That
> > means it's connected to it.
> > 
> > To create a new Smack namespace you need to unshare() user namespace
> > as usual. If that is all you do though, than there is no difference to
> > what is now. To activate the Smack namespace you need to fill the
> > labels' map. It is in a file /proc/$PID/smack_map.
> 
> This should be /proc/$PID/attr/label_map or similar, modeled after the
> existing /proc/$PID/attr/current and similar nodes.  Then it isn't
> module-specific and can be reused for other modules.

Sure. I had some thoughts about that, but couldn't really figure out
which option would be best. I'll change it as suggested.


> > Writing to the map file is not disabled after the first write as it is
> > in uid_map. For Smack we have no means to map ranges of labels, hence
> > it can really be advantageous to be able to expand the map later
> > on. But you can only add to the map. You cannot remove already mapped
> > labels. You cannot change the already existing mappings. Also mappings
> > has to be 1-1. All requests to create a map where either the unmapped
> > or the mapped label already exists in the map will be denied.
> 
> Isn't it a concern that I can then add additional labels to the mapping
> for which I am not authorized?  Or is this mitigated by the fact that I
> cannot alter the rules?  

You can't add mappings for which you are not authorized.
This is mitigated by both, by the fact that adding a mapping is a
privileged operation in the parent (only init for now) namespace and
that modifying the rules is a privileged operation allowed only in the
init namespace (as it is now).


> What about the situation for the predefined
> labels in Smack - are you assuming that they will always be mapped up
> front in the mapping file?

If somebody wants to have a full Smack aware container with full Smack
functionality that's what I'd expect, but it's not mandatory.



-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 0/7] Smack namespace

[Stephen Smalley]

On 05/26/2015 12:27 PM, Lukasz Pawelczyk wrote:
> Hi,
> 
> Thanks for taking the interest and commenting on this.
> Replies below.
> 
> 
> On wto, 2015-05-26 at 10:35 -0400, Stephen Smalley wrote:
>> On 05/25/2015 08:32 AM, Lukasz Pawelczyk wrote:
>>> --- Design ideas ---
>>>
>>> "Smack namespace" is rather "Smack labels namespace" as not the whole
>>> MAC is namespaced, only the labels. There is a great analogy between
>>> Smack labels namespace and the user namespace part that remaps UIDs.
>>>
>>> The idea is to create a map of labels for a namespace so the namespace
>>> is only allowed to use those labels. Smack rules are always the same
>>> as in the init namespace (limited only by what labels are mapped) and
>>> cannot be manipulated from the child namespace. The map is actually
>>> only for labels' names. The underlying structures for labels remain
>>> the same. The filesystem also stores the "unmapped" labels from the
>>> init namespace.
>>
>> How do you achieve that without introducing additional hooks or
>> reworking the current hooks in the setxattr code path?  At present, the
>> security module is allowed to rewrite getxattr requests on the
>> security.* namespace but it isn't allowed to do that for setxattr, so if
>> the process invokes setxattr with a mapped label, then it will be the
>> mapped label that gets passed to the filesystem implementation, not the
>> unmapped label.  The security module may internally store it in unmapped
>> form and may even return that upon getxattr() calls, but if you then
>> reboot the system and later fetch from the filesystem, it will get the
>> mapped label value.
> 
> I call the inode operation by hand in the post_setxattr.
> 
> The label will effectively be set twice, which is not ideal, but there
> is no other option right now without reworking the hooks as you said.
> 
> This shouldn't really be a problem because the Smack operations will not
> use the filesystem label (even when it's set incorrectly for a moment)
> but an already initialized smack_known structure for this inode that has
> all the values filled in properly.
> 
> The only attack vector I can think of is hard rebooting the machine in a
> way that mapped label is really saved in the filesystem before the
> unmapped will have a chance. Should I be worried about that? This sounds
> a little unreal.

If it were my security module, I would be worried about it.  Even aside
from maliciously induced failure, you are leaving yourself open to
inconsistencies arising upon crashes.  I would suggest modifying the
setxattr hook so that the security module can override the original
value/size pair with its own definition before it is passed to the inode
operation.  There is already precedent in that security modules are
allowed to override the value/size returned by getxattr for security.*,
so this just makes them fully parallel.

Re: [PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

On wto, 2015-05-26 at 12:34 -0400, Stephen Smalley wrote:
> > On wto, 2015-05-26 at 10:35 -0400, Stephen Smalley wrote:
> >> On 05/25/2015 08:32 AM, Lukasz Pawelczyk wrote:
> > 
> > I call the inode operation by hand in the post_setxattr.
> > 
> > The label will effectively be set twice, which is not ideal, but there
> > is no other option right now without reworking the hooks as you said.
> > 
> > This shouldn't really be a problem because the Smack operations will not
> > use the filesystem label (even when it's set incorrectly for a moment)
> > but an already initialized smack_known structure for this inode that has
> > all the values filled in properly.
> > 
> > The only attack vector I can think of is hard rebooting the machine in a
> > way that mapped label is really saved in the filesystem before the
> > unmapped will have a chance. Should I be worried about that? This sounds
> > a little unreal.
> 
> If it were my security module, I would be worried about it.  Even aside
> from maliciously induced failure, you are leaving yourself open to
> inconsistencies arising upon crashes.  I would suggest modifying the
> setxattr hook so that the security module can override the original
> value/size pair with its own definition before it is passed to the inode
> operation.  There is already precedent in that security modules are
> allowed to override the value/size returned by getxattr for security.*,
> so this just makes them fully parallel.

Will do. Thank you.


-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 0/7] Smack namespace

[Lukasz Pawelczyk]

On wto, 2015-05-26 at 10:35 -0400, Stephen Smalley wrote:
> On 05/25/2015 08:32 AM, Lukasz Pawelczyk wrote:
> > --- Usage ---
> > 
> > Smack namespace is written using LSM hooks inside user namespace. That
> > means it's connected to it.
> > 
> > To create a new Smack namespace you need to unshare() user namespace
> > as usual. If that is all you do though, than there is no difference to
> > what is now. To activate the Smack namespace you need to fill the
> > labels' map. It is in a file /proc/$PID/smack_map.
> 
> This should be /proc/$PID/attr/label_map or similar, modeled after the
> existing /proc/$PID/attr/current and similar nodes.  Then it isn't
> module-specific and can be reused for other modules.

To make this generic I'll have to introduce new LSH hooks to handle this
file (much like /proc/$PID/attr/current).
I take this is what you had in mind.


-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v2 0/7] Smack namespace

[Stephen Smalley]

On 05/27/2015 05:36 AM, Lukasz Pawelczyk wrote:
> On wto, 2015-05-26 at 10:35 -0400, Stephen Smalley wrote:
>> On 05/25/2015 08:32 AM, Lukasz Pawelczyk wrote:
>>> --- Usage ---
>>>
>>> Smack namespace is written using LSM hooks inside user namespace. That
>>> means it's connected to it.
>>>
>>> To create a new Smack namespace you need to unshare() user namespace
>>> as usual. If that is all you do though, than there is no difference to
>>> what is now. To activate the Smack namespace you need to fill the
>>> labels' map. It is in a file /proc/$PID/smack_map.
>>
>> This should be /proc/$PID/attr/label_map or similar, modeled after the
>> existing /proc/$PID/attr/current and similar nodes.  Then it isn't
>> module-specific and can be reused for other modules.
> 
> To make this generic I'll have to introduce new LSH hooks to handle this
> file (much like /proc/$PID/attr/current).
> I take this is what you had in mind.

We don't have separate hooks for the
/proc/self/attr/{current,exec,fscreate,keycreate,socketcreate,prev}
nodes.  Just one hook that passes the attribute name, and then the
security hook implementation can distinguish on that.