[PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[PATCH v3 01/11] user_ns: 3 new LSM 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@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 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 9429f05..228558c 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1261,6 +1261,23 @@
  *	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 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
@@ -1613,6 +1630,12 @@ union security_list_options {
 				struct audit_context *actx);
 	void (*audit_rule_free)(void *lsmrule);
 #endif /* CONFIG_AUDIT */
+
+#ifdef CONFIG_USER_NS
+	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_USER_NS */
 };
 
 struct security_hook_heads {
@@ -1824,6 +1847,11 @@ struct security_hook_heads {
 	struct list_head audit_rule_match;
 	struct list_head audit_rule_free;
 #endif /* CONFIG_AUDIT */
+#ifdef CONFIG_USER_NS
+	struct list_head userns_create;
+	struct list_head userns_free;
+	struct list_head userns_setns;
+#endif /* CONFIG_USER_NS */
 };
 
 /*
diff --git a/include/linux/security.h b/include/linux/security.h
index 79d85dd..1b0eccc 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1584,6 +1584,29 @@ static inline void security_audit_rule_free(void *lsmrule)
 #endif /* CONFIG_SECURITY */
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_USER_NS
+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_USER_NS */
+
 #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 595fffa..5e66388 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
@@ -1542,6 +1543,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
 }
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_USER_NS
+
+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_USER_NS */
+
 struct security_hook_heads security_hook_heads = {
 	.binder_set_context_mgr =
 		LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr),
@@ -1886,4 +1906,12 @@ struct security_hook_heads security_hook_heads = {
 	.audit_rule_free =
 		LIST_HEAD_INIT(security_hook_heads.audit_rule_free),
 #endif /* CONFIG_AUDIT */
+#ifdef CONFIG_USER_NS
+	.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_USER_NS */
 };
-- 
2.4.3

[PATCH v3 02/11] lsm: /proc/$PID/attr/label_map file and getprocattr_seq hook

[Lukasz Pawelczyk]

This commit adds a new proc attribute, label_map that is required by an
upcoming Smack namespace. In general it can be used to hold a map of
labels, e.g. to be used in namespaces.

Due to the nature of this file, the standard getprocattr hook might not
be enough to handle it. The map's output can in principle be greater
than page size to which the aforementioned hook is limited.
To handle this properly a getprocattr_seq LSM hook has been added that
makes it possible to handle any chosen proc attr by seq operations.

See the documentation in the patch below for the details about how to
use the hook.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
---
 fs/proc/base.c            | 81 +++++++++++++++++++++++++++++++++++++++++++----
 include/linux/lsm_hooks.h | 15 +++++++++
 include/linux/security.h  |  9 ++++++
 security/security.c       |  8 +++++
 4 files changed, 107 insertions(+), 6 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index aa50d1a..e5ac827 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2338,20 +2338,77 @@ out:
 }
 
 #ifdef CONFIG_SECURITY
+static int proc_pid_attr_open(struct inode *inode, struct file *file)
+{
+	const char *name = file->f_path.dentry->d_name.name;
+	const struct seq_operations *ops;
+	struct task_struct *task;
+	struct seq_file *seq;
+	int ret;
+
+	file->private_data = NULL;
+
+	task = get_proc_task(inode);
+	if (!task)
+		return -ESRCH;
+
+	/* don't use seq_ops if they are not provided by LSM */
+	ret = security_getprocattr_seq(task, name, &ops);
+	if (ret == -EOPNOTSUPP) {
+		put_task_struct(task);
+		return 0;
+	}
+	if (ret) {
+		put_task_struct(task);
+		return ret;
+	}
+
+	ret = seq_open(file, ops);
+	if (ret) {
+		put_task_struct(task);
+		return ret;
+	}
+
+	seq = file->private_data;
+	seq->private = task;
+
+	return 0;
+}
+
+static int proc_pid_attr_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq;
+	struct task_struct *task;
+
+	/* don't use seq_ops if they were not provided by LSM */
+	if (file->private_data == NULL)
+		return 0;
+
+	seq = file->private_data;
+	task = seq->private;
+	put_task_struct(task);
+
+	return seq_release(inode, file);
+}
+
 static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
 				  size_t count, loff_t *ppos)
 {
-	struct inode * inode = file_inode(file);
+	struct inode *inode = file_inode(file);
+	const char *name = file->f_path.dentry->d_name.name;
 	char *p = NULL;
 	ssize_t length;
-	struct task_struct *task = get_proc_task(inode);
+	struct task_struct *task;
+
+	/* use seq_ops if they were provided by LSM */
+	if (file->private_data)
+		return seq_read(file, buf, count, ppos);
 
+	task = get_proc_task(inode);
 	if (!task)
 		return -ESRCH;
 
-	length = security_getprocattr(task,
-				      (char*)file->f_path.dentry->d_name.name,
-				      &p);
+	length = security_getprocattr(task, (char *)name, &p);
 	put_task_struct(task);
 	if (length > 0)
 		length = simple_read_from_buffer(buf, count, ppos, p, length);
@@ -2359,6 +2416,15 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
 	return length;
 }
 
+static loff_t proc_pid_attr_lseek(struct file *file, loff_t offset, int whence)
+{
+	/* use seq_ops if they were provided by LSM */
+	if (file->private_data)
+		return seq_lseek(file, offset, whence);
+
+	return generic_file_llseek(file, offset, whence);
+}
+
 static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 				   size_t count, loff_t *ppos)
 {
@@ -2405,9 +2471,11 @@ out_no_task:
 }
 
 static const struct file_operations proc_pid_attr_operations = {
+	.open		= proc_pid_attr_open,
+	.release	= proc_pid_attr_release,
 	.read		= proc_pid_attr_read,
+	.llseek		= proc_pid_attr_lseek,
 	.write		= proc_pid_attr_write,
-	.llseek		= generic_file_llseek,
 };
 
 static const struct pid_entry attr_dir_stuff[] = {
@@ -2417,6 +2485,7 @@ static const struct pid_entry attr_dir_stuff[] = {
 	REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 	REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 	REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
+	REG("label_map",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
 };
 
 static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 228558c..d347e66 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1208,6 +1208,18 @@
  *	@name full extended attribute name to check against
  *	LSM as a MAC label.
  *
+ * @getprocattr_seq:
+ *	An alternative to the getprocattr, that makes it possible for an attr
+ *	file to be handled by seq operations. If this function returns valid
+ *	@ops for a specific @name, those operations will be used and
+ *	getprocattr will not be called.
+ *	A proper task for the file is then passed in seq_file->private.
+ *	@p a task associated with the proc file.
+ *	@name name of the attr file under /proc/$PID/attr/ to be handled.
+ *	@ops (out) seq_operations to be used for @name.
+ *	Return 0 if @name is to be handled by seq, EOPNOTSUPP if getprocattr()
+ *	should be used. Other errors will be passed to user-space.
+ *
  * @secid_to_secctx:
  *	Convert secid to security context.  If secdata is NULL the length of
  *	the result will be returned in seclen, but no secdata will be returned.
@@ -1525,6 +1537,8 @@ union security_list_options {
 
 	void (*d_instantiate)(struct dentry *dentry, struct inode *inode);
 
+	int (*getprocattr_seq)(struct task_struct *p, const char *name,
+			       const struct seq_operations **ops);
 	int (*getprocattr)(struct task_struct *p, char *name, char **value);
 	int (*setprocattr)(struct task_struct *p, char *name, void *value,
 				size_t size);
@@ -1774,6 +1788,7 @@ struct security_hook_heads {
 	struct list_head sem_semop;
 	struct list_head netlink_send;
 	struct list_head d_instantiate;
+	struct list_head getprocattr_seq;
 	struct list_head getprocattr;
 	struct list_head setprocattr;
 	struct list_head ismaclabel;
diff --git a/include/linux/security.h b/include/linux/security.h
index 1b0eccc..3090bb2 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -345,6 +345,8 @@ int security_sem_semctl(struct sem_array *sma, int cmd);
 int security_sem_semop(struct sem_array *sma, struct sembuf *sops,
 			unsigned nsops, int alter);
 void security_d_instantiate(struct dentry *dentry, struct inode *inode);
+int security_getprocattr_seq(struct task_struct *p, const char *name,
+			     const struct seq_operations **ops);
 int security_getprocattr(struct task_struct *p, char *name, char **value);
 int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
@@ -1057,6 +1059,13 @@ static inline int security_sem_semop(struct sem_array *sma,
 static inline void security_d_instantiate(struct dentry *dentry, struct inode *inode)
 { }
 
+static inline int security_getprocattr_seq(struct task_struct *p,
+					   const char *name,
+					   const struct seq_operations **ops)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int security_getprocattr(struct task_struct *p, char *name, char **value)
 {
 	return -EINVAL;
diff --git a/security/security.c b/security/security.c
index 5e66388..e348e38 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1126,6 +1126,12 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
 }
 EXPORT_SYMBOL(security_d_instantiate);
 
+int security_getprocattr_seq(struct task_struct *p, const char *name,
+			     const struct seq_operations **ops)
+{
+	return call_int_hook(getprocattr_seq, -EOPNOTSUPP, p, name, ops);
+}
+
 int security_getprocattr(struct task_struct *p, char *name, char **value)
 {
 	return call_int_hook(getprocattr, -EINVAL, p, name, value);
@@ -1778,6 +1784,8 @@ struct security_hook_heads security_hook_heads = {
 	.netlink_send =	LIST_HEAD_INIT(security_hook_heads.netlink_send),
 	.d_instantiate =
 		LIST_HEAD_INIT(security_hook_heads.d_instantiate),
+	.getprocattr_seq =
+		LIST_HEAD_INIT(security_hook_heads.getprocattr_seq),
 	.getprocattr =	LIST_HEAD_INIT(security_hook_heads.getprocattr),
 	.setprocattr =	LIST_HEAD_INIT(security_hook_heads.setprocattr),
 	.ismaclabel =	LIST_HEAD_INIT(security_hook_heads.ismaclabel),
-- 
2.4.3

[PATCH v3 03/11] lsm: add file opener's cred to a setprocattr arguments

[Lukasz Pawelczyk]

setprocattr hook for Smack's label_map attribute needs to know the
capabilities of file opener. Add those credentials to the hook's
arguments.

While at it add documentation on get/setprocattr hooks.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
---
 fs/proc/base.c             |  2 +-
 include/linux/lsm_hooks.h  | 18 ++++++++++++++++--
 include/linux/security.h   |  7 +++++--
 security/apparmor/lsm.c    |  5 +++--
 security/security.c        |  6 ++++--
 security/selinux/hooks.c   |  2 +-
 security/smack/smack_lsm.c |  4 ++--
 7 files changed, 32 insertions(+), 12 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index e5ac827..775372c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2458,7 +2458,7 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
 	if (length < 0)
 		goto out_free;
 
-	length = security_setprocattr(task,
+	length = security_setprocattr(task, file->f_cred,
 				      (char*)file->f_path.dentry->d_name.name,
 				      (void*)page, count);
 	mutex_unlock(&task->signal->cred_guard_mutex);
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index d347e66..1751864 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1220,6 +1220,20 @@
  *	Return 0 if @name is to be handled by seq, EOPNOTSUPP if getprocattr()
  *	should be used. Other errors will be passed to user-space.
  *
+ * @getprocattr:
+ *	Get a value of a proc security attribute in /proc/$PID/attr/.
+ *	@p a task associated with the proc file.
+ *	@name a name of the file in question.
+ *	@value a pointer where to return the attribute's value.
+ *
+ * @setprocattr:
+ *	Set a value of a proc security attribute in /proc/$PID/attr/.
+ *	@p a task associated with the proc file.
+ *	@f_cred credentials of a file's opener.
+ *	@name a name of the file in question.
+ *	@value a pointer where a value to set is kept.
+ *	@size a number of bytes to read from the @value pointer.
+ *
  * @secid_to_secctx:
  *	Convert secid to security context.  If secdata is NULL the length of
  *	the result will be returned in seclen, but no secdata will be returned.
@@ -1540,8 +1554,8 @@ union security_list_options {
 	int (*getprocattr_seq)(struct task_struct *p, const char *name,
 			       const struct seq_operations **ops);
 	int (*getprocattr)(struct task_struct *p, char *name, char **value);
-	int (*setprocattr)(struct task_struct *p, char *name, void *value,
-				size_t size);
+	int (*setprocattr)(struct task_struct *p, const struct cred *f_cred,
+			   char *name, void *value, size_t size);
 	int (*ismaclabel)(const char *name);
 	int (*secid_to_secctx)(u32 secid, char **secdata, u32 *seclen);
 	int (*secctx_to_secid)(const char *secdata, u32 seclen, u32 *secid);
diff --git a/include/linux/security.h b/include/linux/security.h
index 3090bb2..f0d2914 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -348,7 +348,8 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode);
 int security_getprocattr_seq(struct task_struct *p, const char *name,
 			     const struct seq_operations **ops);
 int security_getprocattr(struct task_struct *p, char *name, char **value);
-int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
+int security_setprocattr(struct task_struct *p, const struct cred *f_cred,
+			 char *name, void *value, size_t size);
 int security_netlink_send(struct sock *sk, struct sk_buff *skb);
 int security_ismaclabel(const char *name);
 int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
@@ -1071,7 +1072,9 @@ static inline int security_getprocattr(struct task_struct *p, char *name, char *
 	return -EINVAL;
 }
 
-static inline int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
+static inline int security_setprocattr(struct task_struct *p,
+				       const struct cred *f_cred,
+				       char *name, void *value, size_t size)
 {
 	return -EINVAL;
 }
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index dec607c..1212927 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -518,8 +518,9 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
 	return error;
 }
 
-static int apparmor_setprocattr(struct task_struct *task, char *name,
-				void *value, size_t size)
+static int apparmor_setprocattr(struct task_struct *task,
+				const struct cred *f_cred,
+				char *name, void *value, size_t size)
 {
 	struct common_audit_data sa;
 	struct apparmor_audit_data aad = {0,};
diff --git a/security/security.c b/security/security.c
index e348e38..88a3b78 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1137,9 +1137,11 @@ int security_getprocattr(struct task_struct *p, char *name, char **value)
 	return call_int_hook(getprocattr, -EINVAL, p, name, value);
 }
 
-int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
+int security_setprocattr(struct task_struct *p, const struct cred *f_cred,
+			 char *name, void *value, size_t size)
 {
-	return call_int_hook(setprocattr, -EINVAL, p, name, value, size);
+	return call_int_hook(setprocattr, -EINVAL, p, f_cred,
+			     name, value, size);
 }
 
 int security_netlink_send(struct sock *sk, struct sk_buff *skb)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 564079c..3e1b9f7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5556,7 +5556,7 @@ invalid:
 	return -EINVAL;
 }
 
-static int selinux_setprocattr(struct task_struct *p,
+static int selinux_setprocattr(struct task_struct *p, const struct cred *f_cred,
 			       char *name, void *value, size_t size)
 {
 	struct task_security_struct *tsec;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d962f88..cdcabf4 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3450,8 +3450,8 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
  *
  * Returns the length of the smack label or an error code
  */
-static int smack_setprocattr(struct task_struct *p, char *name,
-			     void *value, size_t size)
+static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
+			     char *name, void *value, size_t size)
 {
 	struct task_smack *tsp;
 	struct cred *new;
-- 
2.4.3

[PATCH v3 04/11] lsm: inode_pre_setxattr hook

[Lukasz Pawelczyk]

Add a new LSM hook called before inode's setxattr. It is required for
LSM to be able to reliably replace the xattr's value to be set to
filesystem in __vfs_setxattr_noperm(). Useful for mapped values, like in
the upcoming Smack namespace patches.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
---
 fs/xattr.c                | 10 ++++++++++
 include/linux/lsm_hooks.h |  9 +++++++++
 include/linux/security.h  | 10 ++++++++++
 security/security.c       | 12 ++++++++++++
 4 files changed, 41 insertions(+)

diff --git a/fs/xattr.c b/fs/xattr.c
index 072fee1..cbc8d19 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -100,12 +100,22 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
 	if (issec)
 		inode->i_flags &= ~S_NOSEC;
 	if (inode->i_op->setxattr) {
+		bool alloc = false;
+
+		error = security_inode_pre_setxattr(dentry, name, &value,
+						    &size, flags, &alloc);
+		if (error)
+			return error;
+
 		error = inode->i_op->setxattr(dentry, name, value, size, flags);
 		if (!error) {
 			fsnotify_xattr(dentry);
 			security_inode_post_setxattr(dentry, name, value,
 						     size, flags);
 		}
+
+		if (alloc)
+			kfree(value);
 	} else if (issec) {
 		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
 		error = security_inode_setsecurity(inode, suffix, value,
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 1751864..0aeed91 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -349,6 +349,11 @@
  *	Check permission before setting the extended attributes
  *	@value identified by @name for @dentry.
  *	Return 0 if permission is granted.
+ * @inode_pre_setxattr:
+ *	Be able to do some operation before setting the @value identified
+ *	by @name on the filesystem. Replacing the @value and its @size is
+ *	possible. Useful for mapped values. Set @alloc to true if @value
+ *	needs to be kfreed afterwards.
  * @inode_post_setxattr:
  *	Update inode security field after successful setxattr operation.
  *	@value identified by @name for @dentry.
@@ -1448,6 +1453,9 @@ union security_list_options {
 	int (*inode_getattr)(const struct path *path);
 	int (*inode_setxattr)(struct dentry *dentry, const char *name,
 				const void *value, size_t size, int flags);
+	int (*inode_pre_setxattr)(struct dentry *dentry, const char *name,
+				  const void **value, size_t *size,
+				  int flags, bool *alloc);
 	void (*inode_post_setxattr)(struct dentry *dentry, const char *name,
 					const void *value, size_t size,
 					int flags);
@@ -1730,6 +1738,7 @@ struct security_hook_heads {
 	struct list_head inode_setattr;
 	struct list_head inode_getattr;
 	struct list_head inode_setxattr;
+	struct list_head inode_pre_setxattr;
 	struct list_head inode_post_setxattr;
 	struct list_head inode_getxattr;
 	struct list_head inode_listxattr;
diff --git a/include/linux/security.h b/include/linux/security.h
index f0d2914..24f91e0 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -263,6 +263,9 @@ int security_inode_setattr(struct dentry *dentry, struct iattr *attr);
 int security_inode_getattr(const struct path *path);
 int security_inode_setxattr(struct dentry *dentry, const char *name,
 			    const void *value, size_t size, int flags);
+int security_inode_pre_setxattr(struct dentry *dentry, const char *name,
+				const void **value, size_t *size, int flags,
+				bool *alloc);
 void security_inode_post_setxattr(struct dentry *dentry, const char *name,
 				  const void *value, size_t size, int flags);
 int security_inode_getxattr(struct dentry *dentry, const char *name);
@@ -691,6 +694,13 @@ static inline int security_inode_setxattr(struct dentry *dentry,
 	return cap_inode_setxattr(dentry, name, value, size, flags);
 }
 
+static inline int security_inode_pre_setxattr(struct dentry *dentry,
+				const char *name, const void **value,
+				size_t *size, int flags, bool *alloc)
+{
+	return 0;
+}
+
 static inline void security_inode_post_setxattr(struct dentry *dentry,
 		const char *name, const void *value, size_t size, int flags)
 { }
diff --git a/security/security.c b/security/security.c
index 88a3b78..e1d2c6f 100644
--- a/security/security.c
+++ b/security/security.c
@@ -649,6 +649,16 @@ int security_inode_setxattr(struct dentry *dentry, const char *name,
 	return evm_inode_setxattr(dentry, name, value, size);
 }
 
+int security_inode_pre_setxattr(struct dentry *dentry, const char *name,
+				const void **value, size_t *size, int flags,
+				bool *alloc)
+{
+	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+		return 0;
+	return call_int_hook(inode_pre_setxattr, 0, dentry, name, value, size,
+			     flags, alloc);
+}
+
 void security_inode_post_setxattr(struct dentry *dentry, const char *name,
 				  const void *value, size_t size, int flags)
 {
@@ -1666,6 +1676,8 @@ struct security_hook_heads security_hook_heads = {
 		LIST_HEAD_INIT(security_hook_heads.inode_getattr),
 	.inode_setxattr =
 		LIST_HEAD_INIT(security_hook_heads.inode_setxattr),
+	.inode_pre_setxattr =
+		LIST_HEAD_INIT(security_hook_heads.inode_pre_setxattr),
 	.inode_post_setxattr =
 		LIST_HEAD_INIT(security_hook_heads.inode_post_setxattr),
 	.inode_getxattr =
-- 
2.4.3

[PATCH v3 05/11] 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@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/smack.h        |  5 ++++
 security/smack/smack_access.c | 64 +++++++++++++++++++++++++++++++++++++++----
 security/smack/smack_lsm.c    |  4 +--
 3 files changed, 65 insertions(+), 8 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 69ab9eb..e11cc13 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -272,6 +272,11 @@ 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 *);
+int smack_has_ns_privilege(struct task_struct *task,
+			   struct user_namespace *user_ns,
+			   int cap);
+int smack_has_privilege(struct task_struct *task, int cap);
+int smack_ns_privileged(struct user_namespace *user_ns, int cap);
 int smack_privileged(int cap);
 
 /*
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 00f6b38..188b354 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -629,17 +629,19 @@ LIST_HEAD(smack_onlycap_list);
 DEFINE_MUTEX(smack_onlycap_lock);
 
 /*
- * Is the task privileged and allowed to be privileged
- * by the onlycap rule.
+ * Internal smack capability check complimentary to the
+ * set of kernel capable() and has_capability() functions
  *
- * Returns 1 if the task is allowed to be privileged, 0 if it's not.
+ * For a capability in smack related checks to be effective it needs to:
+ * - be allowed to be privileged by the onlycap rule.
+ * - be in the initial user ns
  */
-int smack_privileged(int cap)
+static int smack_capability_allowed(struct smack_known *skp,
+				    struct user_namespace *user_ns)
 {
-	struct smack_known *skp = smk_of_current();
 	struct smack_onlycap *sop;
 
-	if (!capable(cap))
+	if (user_ns != &init_user_ns)
 		return 0;
 
 	rcu_read_lock();
@@ -658,3 +660,53 @@ int smack_privileged(int cap)
 
 	return 0;
 }
+
+/*
+ * Is the task privileged in a namespace and allowed to be privileged
+ * by additional smack rules.
+ */
+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 additional smack rules.
+ */
+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.
+ */
+int smack_ns_privileged(struct user_namespace *user_ns, int cap)
+{
+	struct smack_known *skp = smk_of_current();
+
+	if (!ns_capable(user_ns, cap))
+		return 0;
+	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.
+ */
+int smack_privileged(int cap)
+{
+	return smack_ns_privileged(&init_user_ns, cap);
+}
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index cdcabf4..6098518 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -413,7 +413,7 @@ 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;
@@ -1805,7 +1805,7 @@ 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);
-- 
2.4.3

[PATCH v3 06/11] smack: don't use implicit star to display smackfs/syslog

[Lukasz Pawelczyk]

Smackfs/syslog is analogous to onlycap and unconfined. When not filled
they don't do anything. In such cases onlycap and unconfined displayed
nothing when read, but syslog unconditionally displayed star. This
doesn't work well with namespaces where the star could have been
unmapped. Besides the meaning of this star was different then a star
that could be written to this file. This was misleading.

This also brings syslog read/write functions on par with onlycap and
unconfined where it is possible to reset the value to NULL as should be
possible according to comment in smackfs.c describing smack_syslog_label
variable.

Before that the initial state was to allow (smack_syslog_label was
NULL), but after writing star to it the current had to be labeled star
as well to have an access, even thought reading the smackfs/syslog
returned the same result in both cases.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
---
 security/smack/smackfs.c | 42 +++++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 15 deletions(-)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 81a2888..89f847bba 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -2362,23 +2362,20 @@ 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;
+	char *smack = "";
 	ssize_t rc = -EINVAL;
 	int asize;
 
 	if (*ppos != 0)
 		return 0;
 
-	if (smack_syslog_label == NULL)
-		skp = &smack_known_star;
-	else
-		skp = smack_syslog_label;
+	if (smack_syslog_label != NULL)
+		smack = smack_syslog_label->smk_known;
 
-	asize = strlen(skp->smk_known) + 1;
+	asize = strlen(smack) + 1;
 
 	if (cn >= asize)
-		rc = simple_read_from_buffer(buf, cn, ppos, skp->smk_known,
-						asize);
+		rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);
 
 	return rc;
 }
@@ -2406,16 +2403,31 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
 	if (data == NULL)
 		return -ENOMEM;
 
-	if (copy_from_user(data, buf, count) != 0)
+	if (copy_from_user(data, buf, count) != 0) {
 		rc = -EFAULT;
-	else {
-		skp = smk_import_entry(data, count);
-		if (IS_ERR(skp))
-			rc = PTR_ERR(skp);
-		else
-			smack_syslog_label = skp;
+		goto freeout;
 	}
 
+	/*
+	 * Clear the smack_syslog_label on invalid label errors. This means
+	 * that we can pass a null string to unset the syslog value.
+	 *
+	 * Importing will also reject a label beginning with '-',
+	 * so "-syslog" will also work.
+	 *
+	 * But do so only on invalid label, not on system errors.
+	 */
+	skp = smk_import_entry(data, count);
+	if (PTR_ERR(skp) == -EINVAL)
+		skp = NULL;
+	else if (IS_ERR(skp)) {
+		rc = PTR_ERR(skp);
+		goto freeout;
+	}
+
+	smack_syslog_label = skp;
+
+freeout:
 	kfree(data);
 	return rc;
 }
-- 
2.4.3

[PATCH v3 07/11] 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
                        pointer

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@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/smack.h        |   2 +
 security/smack/smack_access.c |  41 +++++++++++++
 security/smack/smack_lsm.c    |  76 ++++++++++++------------
 security/smack/smackfs.c      | 131 +++++++++++++++++++++++-------------------
 4 files changed, 154 insertions(+), 96 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index e11cc13..1e225b0 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -278,6 +278,8 @@ int smack_has_ns_privilege(struct task_struct *task,
 int smack_has_privilege(struct task_struct *task, int cap);
 int smack_ns_privileged(struct user_namespace *user_ns, int cap);
 int smack_privileged(int cap);
+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 188b354..eb7c1cc 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -710,3 +710,44 @@ int smack_privileged(int cap)
 {
 	return smack_ns_privileged(&init_user_ns, cap);
 }
+
+/**
+ * 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);
+		kfree(cp);
+	}
+
+	return skp;
+}
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 6098518..8fe6ccc 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -742,31 +742,31 @@ static int smack_set_mnt_opts(struct super_block *sb,
 	for (i = 0; i < num_opts; i++) {
 		switch (opts->mnt_opts_flags[i]) {
 		case FSDEFAULT_MNT:
-			skp = smk_import_entry(opts->mnt_opts[i], 0);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_default = skp;
 			break;
 		case FSFLOOR_MNT:
-			skp = smk_import_entry(opts->mnt_opts[i], 0);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_floor = skp;
 			break;
 		case FSHAT_MNT:
-			skp = smk_import_entry(opts->mnt_opts[i], 0);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_hat = skp;
 			break;
 		case FSROOT_MNT:
-			skp = smk_import_entry(opts->mnt_opts[i], 0);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
 			break;
 		case FSTRANS_MNT:
-			skp = smk_import_entry(opts->mnt_opts[i], 0);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -1284,7 +1284,7 @@ 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 &&
@@ -1318,6 +1318,7 @@ 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) {
@@ -1325,27 +1326,21 @@ 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;
 }
 
 /**
@@ -1439,15 +1434,17 @@ 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);
 	}
 
 	/*
@@ -1470,10 +1467,11 @@ 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;
@@ -3429,7 +3427,10 @@ 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;
 
@@ -3473,7 +3474,7 @@ static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
 	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);
 
@@ -4201,7 +4202,10 @@ 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 89f847bba..6a0a1ec 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -335,36 +335,17 @@ 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)
@@ -587,6 +568,9 @@ 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)
@@ -600,9 +584,13 @@ 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, ' ');
 
@@ -793,6 +781,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 		list_entry_rcu(list, struct smack_known, list);
 	struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
 	char sep = '/';
+	char *cp;
 	int i;
 
 	/*
@@ -806,7 +795,11 @@ 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)) {
@@ -895,7 +888,7 @@ 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;
@@ -984,9 +977,14 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
 		list_entry_rcu(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)) {
@@ -1069,11 +1067,15 @@ 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;
 }
@@ -1219,7 +1221,7 @@ 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;
@@ -1548,6 +1550,7 @@ 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)
@@ -1558,12 +1561,14 @@ 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;
 
@@ -1601,7 +1606,7 @@ 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;
@@ -1641,11 +1646,16 @@ static void *onlycap_seq_next(struct seq_file *s, void *v, loff_t *pos)
 
 static int onlycap_seq_show(struct seq_file *s, void *v)
 {
+	char *smack;
 	struct list_head *list = v;
 	struct smack_onlycap *sop =
 		list_entry_rcu(list, struct smack_onlycap, list);
 
-	seq_puts(s, sop->smk_label->smk_known);
+	smack = smk_find_label_name(sop->smk_label);
+	if (smack == NULL)
+		smack = smack_known_huh.smk_known;
+
+	seq_puts(s, smack);
 	seq_putc(s, ' ');
 
 	return 0;
@@ -1739,7 +1749,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 		if (!*tok)
 			continue;
 
-		skp = smk_import_entry(tok, 0);
+		skp = smk_get_label(tok, 0, true);
 		if (IS_ERR(skp)) {
 			rc = PTR_ERR(skp);
 			break;
@@ -1809,8 +1819,11 @@ 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;
 
@@ -1857,7 +1870,7 @@ 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)) {
@@ -2254,7 +2267,6 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
 	char *data;
-	const char *cp;
 	struct smack_known *skp;
 	struct smack_rule *sp;
 	struct list_head *rule_list;
@@ -2279,15 +2291,13 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 		goto out_data;
 	}
 
-	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 out_data;
 	}
-
-	skp = smk_find_entry(cp);
 	if (skp == NULL)
-		goto out_cp;
+		goto out_data;
 
 	rule_list = &skp->smk_rules;
 	rule_lock = &skp->smk_rules_lock;
@@ -2299,8 +2309,6 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 
 	mutex_unlock(rule_lock);
 
-out_cp:
-	kfree(cp);
 out_data:
 	kfree(data);
 
@@ -2369,8 +2377,11 @@ static ssize_t smk_read_syslog(struct file *filp, char __user *buf,
 	if (*ppos != 0)
 		return 0;
 
-	if (smack_syslog_label != NULL)
-		smack = smack_syslog_label->smk_known;
+	if (smack_syslog_label != NULL) {
+		smack = smk_find_label_name(smack_syslog_label);
+		if (smack == NULL)
+			smack = smack_known_huh.smk_known;
+	}
 
 	asize = strlen(smack) + 1;
 
@@ -2417,7 +2428,7 @@ static ssize_t smk_write_syslog(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)) {
-- 
2.4.3

[PATCH v3 08/11] 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:
- four small helper functions added
- 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@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/smack.h        | 48 ++++++++++++++++++++++++++++++++++-
 security/smack/smack_access.c | 18 +++++++++-----
 security/smack/smack_lsm.c    | 58 ++++++++++++++++---------------------------
 security/smack/smackfs.c      |  4 +--
 4 files changed, 82 insertions(+), 46 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 1e225b0..014a7d1 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -252,6 +252,7 @@ struct smk_audit_info {
 	struct smack_audit_data sad;
 #endif
 };
+
 /*
  * These functions are in smack_lsm.c
  */
@@ -263,7 +264,7 @@ 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);
@@ -318,6 +319,7 @@ 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;
 }
 
@@ -327,10 +329,31 @@ 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)
@@ -365,6 +388,29 @@ 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_user_ns();
+}
+
+/*
  * logging functions
  */
 #define SMACK_AUDIT_DENIED 0x1
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index eb7c1cc..5b13d0c 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 8fe6ccc..d1beff5 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -393,8 +393,6 @@ 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);
@@ -402,13 +400,12 @@ 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)
@@ -416,22 +413,18 @@ 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);
 }
 
 /*
@@ -450,9 +443,7 @@ 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__);
 }
@@ -467,13 +458,9 @@ 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__);
 }
 
 /**
@@ -1688,13 +1675,14 @@ 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();
@@ -3507,11 +3495,13 @@ static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
 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
@@ -3519,19 +3509,15 @@ 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);
 		}
 	}
@@ -3540,8 +3526,8 @@ 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;
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 6a0a1ec..5ffb7df 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -1549,7 +1549,7 @@ 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)
 {
-	ssize_t rc;
+	ssize_t rc = -EINVAL;
 	char *cp;
 	int asize;
 
@@ -1569,8 +1569,6 @@ static ssize_t smk_read_ambient(struct file *filp, char __user *buf,
 
 	if (cn >= asize)
 		rc = simple_read_from_buffer(buf, cn, ppos, cp, asize);
-	else
-		rc = -EINVAL;
 
 	mutex_unlock(&smack_ambient_lock);
 
-- 
2.4.3

[PATCH v3 09/11] 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/attr/label_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@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/Kconfig        |  10 ++
 security/smack/Makefile       |   1 +
 security/smack/smack.h        |  45 ++++-
 security/smack/smack_access.c |  47 ++++-
 security/smack/smack_lsm.c    | 134 +++++++++++++-
 security/smack/smack_ns.c     | 404 ++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 626 insertions(+), 15 deletions(-)
 create mode 100644 security/smack/smack_ns.c

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 014a7d1..e63cf53 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
@@ -268,7 +297,7 @@ 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);
@@ -283,6 +312,20 @@ 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);
+extern const struct seq_operations proc_label_map_seq_operations;
+ssize_t proc_label_map_write(struct task_struct *p, const struct cred *f_cred,
+			     void *value, size_t size);
+#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 5b13d0c..f71ace6 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);
 
@@ -742,17 +773,19 @@ 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);
-		kfree(cp);
+		if (allocated)
+			kfree(cp);
 	}
 
 	return skp;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index d1beff5..8894115 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -42,6 +42,7 @@
 #include <linux/shm.h>
 #include <linux/binfmts.h>
 #include <linux/parser.h>
+#include <linux/user_namespace.h>
 #include "smack.h"
 
 #define TRANS_TRUE	"TRUE"
@@ -3397,6 +3398,27 @@ unlockandout:
 }
 
 /**
+ * smack_getprocattr_seq - Smack process attribute access through seq
+ * @p: the object task
+ * @name: the name of the attribute in /proc/.../attr/
+ * @ops: out, seq_operations to handle @name
+ *
+ * Returns 0 if @name is to be handled by seq, error otherwise.
+ */
+int smack_getprocattr_seq(struct task_struct *p, const char *name,
+			  const struct seq_operations **ops)
+{
+#ifdef CONFIG_SECURITY_SMACK_NS
+	if (strcmp(name, "label_map") == 0) {
+		*ops = &proc_label_map_seq_operations;
+		return 0;
+	}
+#endif
+
+	return -EOPNOTSUPP;
+}
+
+/**
  * smack_getprocattr - Smack process attribute access
  * @p: the object task
  * @name: the name of the attribute in /proc/.../attr
@@ -3428,9 +3450,8 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
 }
 
 /**
- * smack_setprocattr - Smack process attribute setting
+ * proc_current_write - Smack "current" process attribute setting
  * @p: the object task
- * @name: the name of the attribute in /proc/.../attr
  * @value: the value to set
  * @size: the size of the value
  *
@@ -3439,8 +3460,7 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
  *
  * Returns the length of the smack label or an error code
  */
-static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
-			     char *name, void *value, size_t size)
+static int proc_current_write(struct task_struct *p, void *value, size_t size)
 {
 	struct task_smack *tsp;
 	struct cred *new;
@@ -3459,9 +3479,6 @@ static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
 	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
 		return -EINVAL;
 
-	if (strcmp(name, "current") != 0)
-		return -EINVAL;
-
 	skp = smk_get_label(value, size, true);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
@@ -3484,6 +3501,33 @@ static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
 }
 
 /**
+ * smack_setprocattr - Smack process attribute setting
+ * @p: the object task
+ * @cred: the credentials of the file's opener
+ * @name: the name of the attribute in /proc/.../attr
+ * @value: the value to set
+ * @size: the size of the value
+ *
+ * Sets the proc attribute
+ *
+ * Returns the length of the written data or an error code
+ */
+static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
+			     char *name, void *value, size_t size)
+{
+#ifdef CONFIG_SECURITY_SMACK_NS
+	if (strcmp(name, "label_map") == 0)
+		return proc_label_map_write(p, f_cred, value, size);
+#endif
+
+	if (strcmp(name, "current") == 0)
+		return proc_current_write(p, value, size);
+
+	return -EINVAL;
+
+}
+
+/**
  * smack_unix_stream_connect - Smack access on UDS
  * @sock: one sock
  * @other: the other sock
@@ -4324,6 +4368,53 @@ 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.
@@ -4500,6 +4591,7 @@ struct security_hook_list smack_hooks[] = {
 
 	LSM_HOOK_INIT(d_instantiate, smack_d_instantiate),
 
+	LSM_HOOK_INIT(getprocattr_seq, smack_getprocattr_seq),
 	LSM_HOOK_INIT(getprocattr, smack_getprocattr),
 	LSM_HOOK_INIT(setprocattr, smack_setprocattr),
 
@@ -4537,6 +4629,13 @@ 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),
@@ -4549,6 +4648,27 @@ 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..49223c4
--- /dev/null
+++ b/security/smack/smack_ns.c
@@ -0,0 +1,404 @@
+/*
+ * Copyright (C) 2014 Samsung Electronics.
+ *
+ * Smack namespaces
+ *
+ * Author(s):
+ *    Lukasz Pawelczyk <l.pawelczyk@samsung.com>
+ *
+ * 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_label_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_label_map_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct smack_known *skp;
+	struct task_struct *task = seq->private;
+	struct user_namespace *ns = ns_of_task_struct(task);
+	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_label_map_seq_stop(struct seq_file *seq, void *v)
+{
+	rcu_read_unlock();
+}
+
+static void *proc_label_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct smack_known *skp = v;
+	struct task_struct *task = seq->private;
+	struct user_namespace *ns = ns_of_task_struct(task);
+
+	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_label_map_seq_show(struct seq_file *seq, void *v)
+{
+	struct smack_known *skp = v;
+	struct task_struct *task = seq->private;
+	struct user_namespace *ns = ns_of_task_struct(task);
+	struct smack_known_ns *sknp;
+
+	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_label_map_seq_operations = {
+	.start = proc_label_map_seq_start,
+	.stop = proc_label_map_seq_stop,
+	.next = proc_label_map_seq_next,
+	.show = proc_label_map_seq_show,
+};
+
+static DEFINE_MUTEX(smk_map_mutex);
+
+static bool mapping_permitted(const struct cred *f_cred,
+			      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 would effectively give 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 (security_capable(f_cred, user_ns, CAP_MAC_ADMIN) != 0)
+		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) &&
+	    security_capable(f_cred, &init_user_ns, CAP_MAC_ADMIN) == 0)
+		return true;
+
+	return false;
+}
+
+ssize_t proc_label_map_write(struct task_struct *p, const struct cred *f_cred,
+			     void *value, size_t size)
+{
+	struct user_namespace *ns = ns_of_task_struct(p);
+	struct user_namespace *cur_ns = ns_of_current();
+	struct smack_known *skp;
+	struct smack_known_ns *sknp;
+	char *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 (cur_ns != ns->parent)
+		return -EPERM;
+
+	if (!mapping_permitted(f_cred, ns))
+		return -EPERM;
+
+	if (value == NULL || size == 0 || size >= PAGE_SIZE)
+		return -EINVAL;
+
+	mutex_lock(&smk_map_mutex);
+
+	/* Parse the user data */
+	pos = value;
+	pos[size] = '\0';
+
+	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;
+
+		ret = -EEXIST;
+
+		/* 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)
+			goto out;
+
+		skp = smk_import_entry(tok[0], 0);
+		if (IS_ERR(skp)) {
+			ret = PTR_ERR(skp);
+			goto out;
+		}
+
+		/* do not allow remapping */
+		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);
+
+	return ret;
+}
-- 
2.4.3

[PATCH v3 10/11] 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@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/smack.h        |  29 +++-
 security/smack/smack_access.c | 108 ++++++++++--
 security/smack/smack_lsm.c    | 379 +++++++++++++++++++++++++++++++-----------
 security/smack/smack_ns.c     |  39 +++++
 security/smack/smackfs.c      |  57 ++++---
 5 files changed, 471 insertions(+), 141 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index e63cf53..364b2b5 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 */
@@ -292,10 +302,11 @@ 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);
@@ -308,8 +319,9 @@ int smack_has_ns_privilege(struct task_struct *task,
 int smack_has_privilege(struct task_struct *task, int cap);
 int smack_ns_privileged(struct user_namespace *user_ns, int cap);
 int smack_privileged(int cap);
-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
@@ -323,6 +335,15 @@ struct smack_known *smk_find_unmapped(const char *string, int len,
 extern const struct seq_operations proc_label_map_seq_operations;
 ssize_t proc_label_map_write(struct task_struct *p, const struct cred *f_cred,
 			     void *value, size_t size);
+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 */
 
 /*
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index f71ace6..becbe44 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
@@ -671,15 +705,22 @@ DEFINE_MUTEX(smack_onlycap_lock);
  *
  * For a capability in smack related checks to be effective it needs to:
  * - be allowed to be privileged by the onlycap rule.
- * - be in the initial user ns
+ * - be in the initial user ns or have a filled map in the child ns
  */
 static int smack_capability_allowed(struct smack_known *skp,
 				    struct user_namespace *user_ns)
 {
 	struct smack_onlycap *sop;
 
+#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 */
 
 	rcu_read_lock();
 	if (list_empty(&smack_onlycap_list)) {
@@ -749,14 +790,32 @@ int smack_privileged(int cap)
 }
 
 /**
- * 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;
 }
 
 /**
@@ -765,17 +824,32 @@ 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 8894115..c2180de 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -383,6 +383,7 @@ 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
  *
@@ -390,6 +391,7 @@ 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;
@@ -401,21 +403,28 @@ 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,
@@ -425,7 +434,8 @@ 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);
 }
 
 /*
@@ -445,8 +455,9 @@ 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__);
 }
 
 /**
@@ -460,8 +471,10 @@ 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__);
 }
 
 /**
@@ -508,6 +521,7 @@ 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.
 	 */
@@ -523,6 +537,9 @@ 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;
 }
@@ -720,6 +737,7 @@ static int smack_set_mnt_opts(struct super_block *sb,
 	struct smack_known *skp;
 	int i;
 	int num_opts = opts->num_mnt_opts;
+	struct user_namespace *ns = ns_of_current();
 	int transmute = 0;
 
 	if (sp->smk_initialized)
@@ -730,31 +748,31 @@ static int smack_set_mnt_opts(struct super_block *sb,
 	for (i = 0; i < num_opts; i++) {
 		switch (opts->mnt_opts_flags[i]) {
 		case FSDEFAULT_MNT:
-			skp = smk_get_label(opts->mnt_opts[i], 0, true);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_default = skp;
 			break;
 		case FSFLOOR_MNT:
-			skp = smk_get_label(opts->mnt_opts[i], 0, true);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_floor = skp;
 			break;
 		case FSHAT_MNT:
-			skp = smk_get_label(opts->mnt_opts[i], 0, true);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_hat = skp;
 			break;
 		case FSROOT_MNT:
-			skp = smk_get_label(opts->mnt_opts[i], 0, true);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
 			break;
 		case FSTRANS_MNT:
-			skp = smk_get_label(opts->mnt_opts[i], 0, true);
+			skp = smk_get_label(opts->mnt_opts[i], 0, true, ns);
 			if (IS_ERR(skp))
 				return PTR_ERR(skp);
 			sp->smk_root = skp;
@@ -765,7 +783,12 @@ static int smack_set_mnt_opts(struct super_block *sb,
 		}
 	}
 
-	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.
 		 */
@@ -794,6 +817,12 @@ static int smack_set_mnt_opts(struct super_block *sb,
 	if (transmute)
 		isp->smk_flags |= SMK_INODE_TRANSMUTE;
 
+	/*
+	 * Set the superblock namespace from a mounting process
+	 */
+	put_user_ns(sp->smk_ns);
+	sp->smk_ns = get_user_ns(ns);
+
 	return 0;
 }
 
@@ -844,7 +873,7 @@ 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;
 }
@@ -864,6 +893,7 @@ 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)
@@ -873,6 +903,13 @@ 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;
@@ -880,9 +917,8 @@ 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();
 
@@ -1023,6 +1059,7 @@ 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;
 
@@ -1030,13 +1067,13 @@ 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);
 	}
 
@@ -1054,6 +1091,7 @@ 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;
 
@@ -1063,7 +1101,7 @@ 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) {
 		/*
@@ -1071,7 +1109,7 @@ 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;
@@ -1087,6 +1125,7 @@ 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;
 
@@ -1096,7 +1135,8 @@ 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) {
 		/*
@@ -1104,7 +1144,7 @@ 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);
 	}
 
@@ -1128,21 +1168,22 @@ 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;
@@ -1159,6 +1200,7 @@ 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;
@@ -1175,7 +1217,7 @@ 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;
 }
@@ -1189,6 +1231,7 @@ 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;
 
@@ -1200,7 +1243,8 @@ 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;
 }
@@ -1214,13 +1258,14 @@ 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;
 }
@@ -1242,6 +1287,9 @@ 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;
@@ -1268,11 +1316,12 @@ 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 &&
@@ -1284,7 +1333,7 @@ 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);
 	}
 
@@ -1292,6 +1341,40 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
 }
 
 /**
+ * smack_inode_pre_setxattr - Unmap the namespaced label
+ * @dentry: object
+ * @name: attribute name
+ * @value: attribute value
+ * @size: attribute size
+ * @flags: unused
+ * @alloc: unused
+ *
+ * Guarantees that the real label value will be written to the filesystem.
+ */
+static int smack_inode_pre_setxattr(struct dentry *dentry, const char *name,
+				    const void **value, size_t *size, int flags,
+				    bool *alloc)
+{
+	struct smack_known *skp;
+	struct user_namespace *ns = ns_of_current();
+
+	if (strcmp(name, XATTR_NAME_SMACK) != 0 &&
+	    strcmp(name, XATTR_NAME_SMACKEXEC) != 0 &&
+	    strcmp(name, XATTR_NAME_SMACKMMAP) != 0)
+		return 0;
+
+	/* Convert value to non namespaced label */
+	skp = smk_get_label(*value, *size, true, ns);
+	if (IS_ERR(skp))
+		return PTR_ERR(skp);
+
+	*value = skp->smk_known;
+	*size = strlen(skp->smk_known);
+
+	return 0;
+}
+
+/**
  * smack_inode_post_setxattr - Apply the Smack update approved above
  * @dentry: object
  * @name: attribute name
@@ -1322,7 +1405,8 @@ 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);
+		/* value has been un-namespaced in inode_pre_setxattr() */
+		skp = smk_get_label(value, size, true, &init_user_ns);
 
 		if (!IS_ERR(skp))
 			*skpp = skp;
@@ -1340,13 +1424,15 @@ 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;
 }
@@ -1363,6 +1449,9 @@ 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;
 
@@ -1372,7 +1461,8 @@ 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);
@@ -1383,7 +1473,7 @@ 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;
@@ -1423,13 +1513,18 @@ 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);
@@ -1456,7 +1551,7 @@ 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);
@@ -1567,18 +1662,19 @@ 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);
 	}
 
@@ -1596,11 +1692,12 @@ 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;
 }
@@ -1622,6 +1719,7 @@ 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) {
@@ -1631,14 +1729,14 @@ 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:
@@ -1668,6 +1766,7 @@ 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;
@@ -1678,12 +1777,16 @@ 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();
@@ -1699,6 +1802,7 @@ 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.
@@ -1778,8 +1882,10 @@ 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;
 
@@ -1787,12 +1893,17 @@ 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);
@@ -1812,6 +1923,7 @@ 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)))
@@ -1827,7 +1939,7 @@ 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;
 }
@@ -1847,16 +1959,19 @@ 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;
@@ -2011,12 +2126,13 @@ 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;
 }
@@ -2157,6 +2273,7 @@ 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);
@@ -2166,7 +2283,7 @@ 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;
 	}
@@ -2176,8 +2293,9 @@ 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;
 }
 
@@ -2232,6 +2350,7 @@ 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);
@@ -2241,6 +2360,7 @@ 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;
 
@@ -2255,7 +2375,11 @@ 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;
 }
 
 /**
@@ -2350,6 +2474,7 @@ 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;
@@ -2369,7 +2494,8 @@ 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;
@@ -2471,6 +2597,7 @@ 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;
@@ -2528,7 +2655,7 @@ 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;
 }
@@ -2553,12 +2680,13 @@ 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);
 
@@ -2743,14 +2871,14 @@ 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;
 }
 
 /**
@@ -2762,9 +2890,16 @@ 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;
+
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
 
-	isp->security = skp;
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
+
+	isp->security = ssp;
 	return 0;
 }
 
@@ -2777,7 +2912,10 @@ 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;
 }
 
@@ -2790,7 +2928,7 @@ 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;
 
@@ -2798,8 +2936,8 @@ 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;
 }
 
@@ -2870,14 +3008,14 @@ 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;
 }
 
 /**
@@ -2889,9 +3027,16 @@ 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;
+
+	ssp = kzalloc(sizeof(struct ipc_smack), GFP_KERNEL);
+	if (ssp == NULL)
+		return -ENOMEM;
 
-	isp->security = skp;
+	ssp->smk_known = smk_of_current();
+	ssp->smk_ns = get_user_ns(ns_of_current());
+
+	isp->security = ssp;
 	return 0;
 }
 
@@ -2904,7 +3049,10 @@ 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;
 }
 
@@ -2917,7 +3065,7 @@ 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;
 
@@ -2925,8 +3073,8 @@ 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;
 }
 
@@ -3011,9 +3159,16 @@ 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;
 
-	kisp->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());
+
+	kisp->security = ssp;
 	return 0;
 }
 
@@ -3026,19 +3181,22 @@ 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;
 }
 
 /**
@@ -3050,7 +3208,7 @@ 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;
 
@@ -3058,8 +3216,8 @@ 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;
 }
 
@@ -3153,7 +3311,7 @@ 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;
@@ -3162,8 +3320,8 @@ 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;
 }
 
@@ -3174,9 +3332,9 @@ 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;
 }
 
 /**
@@ -3431,13 +3589,14 @@ int smack_getprocattr_seq(struct task_struct *p, const char *name,
 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);
@@ -3465,6 +3624,7 @@ static int proc_current_write(struct task_struct *p, void *value, size_t size)
 	struct task_smack *tsp;
 	struct cred *new;
 	struct smack_known *skp;
+	struct user_namespace *ns;
 
 	/*
 	 * Changing another process' Smack value is too dangerous
@@ -3473,13 +3633,15 @@ static int proc_current_write(struct task_struct *p, void *value, size_t size)
 	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)
 		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);
 
@@ -3546,23 +3708,27 @@ 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);
 		}
 	}
 
@@ -3589,6 +3755,8 @@ 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;
 
@@ -3599,10 +3767,11 @@ 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;
 }
@@ -3842,7 +4011,7 @@ 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)
@@ -3864,7 +4033,7 @@ 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 */
@@ -4077,7 +4246,7 @@ 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;
@@ -4181,6 +4350,7 @@ 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;
 
@@ -4207,7 +4377,7 @@ 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;
 }
@@ -4224,6 +4394,7 @@ 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;
 
@@ -4232,7 +4403,7 @@ 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);
@@ -4410,6 +4581,11 @@ 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;
 }
 
@@ -4522,6 +4698,7 @@ struct security_hook_list smack_hooks[] = {
 	LSM_HOOK_INIT(inode_setattr, smack_inode_setattr),
 	LSM_HOOK_INIT(inode_getattr, smack_inode_getattr),
 	LSM_HOOK_INIT(inode_setxattr, smack_inode_setxattr),
+	LSM_HOOK_INIT(inode_pre_setxattr, smack_inode_pre_setxattr),
 	LSM_HOOK_INIT(inode_post_setxattr, smack_inode_post_setxattr),
 	LSM_HOOK_INIT(inode_getxattr, smack_inode_getxattr),
 	LSM_HOOK_INIT(inode_removexattr, smack_inode_removexattr),
diff --git a/security/smack/smack_ns.c b/security/smack/smack_ns.c
index 49223c4..dc2a666 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_label_map_seq_start(struct seq_file *seq, loff_t *pos)
 {
 	struct smack_known *skp;
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 5ffb7df..f817cd3 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -335,13 +335,15 @@ 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)
@@ -568,6 +570,7 @@ 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;
 
@@ -576,6 +579,7 @@ 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)
@@ -584,8 +588,8 @@ 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;
@@ -780,6 +784,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
 	struct smack_known *skp =
 		list_entry_rcu(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;
@@ -795,7 +800,7 @@ 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;
 
@@ -848,6 +853,7 @@ 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;
@@ -888,7 +894,7 @@ 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;
@@ -976,11 +982,12 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
 	struct smack_known *skp =
 		list_entry_rcu(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;
 
@@ -1067,7 +1074,8 @@ 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;
@@ -1164,6 +1172,7 @@ 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);
@@ -1221,7 +1230,7 @@ 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;
@@ -1549,6 +1558,7 @@ 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 = -EINVAL;
 	char *cp;
 	int asize;
@@ -1561,7 +1571,7 @@ 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;
 
@@ -1588,6 +1598,7 @@ 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;
@@ -1604,7 +1615,7 @@ 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;
@@ -1645,11 +1656,12 @@ static void *onlycap_seq_next(struct seq_file *s, void *v, loff_t *pos)
 static int onlycap_seq_show(struct seq_file *s, void *v)
 {
 	char *smack;
+	struct user_namespace *ns = ns_of_current();
 	struct list_head *list = v;
 	struct smack_onlycap *sop =
 		list_entry_rcu(list, struct smack_onlycap, list);
 
-	smack = smk_find_label_name(sop->smk_label);
+	smack = smk_find_label_name(sop->smk_label, ns);
 	if (smack == NULL)
 		smack = smack_known_huh.smk_known;
 
@@ -1728,6 +1740,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 	struct smack_onlycap *sop;
 	struct smack_onlycap *sop2;
 	LIST_HEAD(list_tmp);
+	struct user_namespace *ns = ns_of_current();
 	int rc = count;
 
 	if (!smack_privileged(CAP_MAC_ADMIN))
@@ -1747,7 +1760,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
 		if (!*tok)
 			continue;
 
-		skp = smk_get_label(tok, 0, true);
+		skp = smk_get_label(tok, 0, true, ns);
 		if (IS_ERR(skp)) {
 			rc = PTR_ERR(skp);
 			break;
@@ -1813,12 +1826,13 @@ 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;
 	}
@@ -1845,6 +1859,7 @@ 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))
@@ -1868,7 +1883,7 @@ 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)) {
@@ -2040,6 +2055,7 @@ 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;
 
@@ -2059,7 +2075,7 @@ 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;
@@ -2269,6 +2285,7 @@ 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)
@@ -2289,7 +2306,7 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
 		goto out_data;
 	}
 
-	skp = smk_get_label(data, count, false);
+	skp = smk_get_label(data, count, false, ns);
 	if (IS_ERR(skp)) {
 		rc = PTR_ERR(skp);
 		goto out_data;
@@ -2371,12 +2388,13 @@ static ssize_t smk_read_syslog(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_syslog_label != NULL) {
-		smack = smk_find_label_name(smack_syslog_label);
+		smack = smk_find_label_name(smack_syslog_label, ns);
 		if (smack == NULL)
 			smack = smack_known_huh.smk_known;
 	}
@@ -2403,6 +2421,7 @@ 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))
@@ -2426,7 +2445,7 @@ static ssize_t smk_write_syslog(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)) {
-- 
2.4.3

[PATCH v3 11/11] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

Adds Documentation/smack-namespace.txt.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
---
 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..120314d
--- /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/attr/label_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 label_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 label_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 a226416..6effb1a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9377,6 +9377,7 @@ 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.
-- 
2.4.3

Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:45PM +0200, 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.
> +
> +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.

(Sorry it took me this long to get to reading, and thanks for working
on this)

Oh my.  All this is not at all what I'd expected :)

Is there rationale for these decisions?  Hm, I guess it really is
following the user_ns design, but the huge difference is that the
user_ns is partitioning an already-enumerated set of kuids.  The
smack labels are inherently different.

In containers, something we'd really like to be able to do is:

Create a new container.  Just run it as label 'c1'.  Inside the
container, let the admin install mysql from a package which assigns
type 'mysqld', protecting the rest of the container from mysql.
Without the host admin doing anything.

Normally the way I think of implementing something like this would be
to allow the host to say "c1 is to be namespaceable."  Then on a userns
unshare, if the task is in c1, it gets transitioned into the ns.  Then the
container sees c1 as _ (or whatever).  It can create 'mysql' which is
actually 'c1.mysql' on the host, and it can create and override rules
to c1.*.

Also, allowing CAP_MAC_OVERRIDE in this way seems overly dangerous.
If there were rules defined by the container, then I'd expect those to
be overrideable - but not all rules pertaining to all labels mapped
into the container.  But I guess based on  your envisioned usage (where
I assume 'label1' is meant to *only* be used for that container) it
might be ok.

thanks,
-serge

Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

[-- Attachment #1.1: Type: text/plain, Size: 6484 bytes --]

On Wed, Jul 29, 2015 at 5:25 PM, Serge E. Hallyn <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org> wrote:

> On Fri, Jul 24, 2015 at 12:04:45PM +0200, 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.
> > +
> > +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.
>
> (Sorry it took me this long to get to reading, and thanks for working
> on this)
>
> Oh my.  All this is not at all what I'd expected :)
>
> Is there rationale for these decisions?  Hm, I guess it really is
> following the user_ns design, but the huge difference is that the
> user_ns is partitioning an already-enumerated set of kuids.  The
> smack labels are inherently different.
>

There is a big rationale for this. This is not to make Smack limit how
namespace can be created (this can be done separately, no conflict here).
This is to make Smack work at all inside a namespace. Please note that
contrary to SELinux and AppArmor Smack needs CAP_MAC_ADMIN for it to
operate on a normal basis. There is no rule for changing labels.
CAP_MAC_ADMIN is always required for this. And you cannot unlock and give
this capability just like that to anyone. Like in every namespace you need
a level of abstraction to allow an unprivileged namespace to administer
something.


>
> In containers, something we'd really like to be able to do is:
>
> Create a new container.  Just run it as label 'c1'.  Inside the
> container, let the admin install mysql from a package which assigns
> type 'mysqld', protecting the rest of the container from mysql.
> Without the host admin doing anything.
>
> Normally the way I think of implementing something like this would be
> to allow the host to say "c1 is to be namespaceable."  Then on a userns
> unshare, if the task is in c1, it gets transitioned into the ns.  Then the
> container sees c1 as _ (or whatever).  It can create 'mysql' which is
> actually 'c1.mysql' on the host, and it can create and override rules
> to c1.*.
>

Few things here.
1. Such an extension with using prefixes (with two exceptions, see below)
could be added to my patches. I even planned to do so (make a prefix for a
container and assign it a group of labels, this doesn't conflict with
arbitrary mapping). But this was refused by Casey on a basis that by Smack
defintion labels have no meaning. So no prefixes.
2. (expcetion #1) Changing any rules in a container has been deemed too
insecure at this point.
3. (expcetion #2) About the: "Without the host admin doing anything.". With
this namespace you delegate part of CAP_MAC_ADMIN privilege to an
unprivileged user (as with any other namespace). There is now way that this
will not involve host admin. The way you described it you allow an
unprivileged process to change its own label and change labels on a
filesystem. This is simply against Smack rules and completely insecure.
Even with user_ns if you map several UID you need admin intervention.


> Also, allowing CAP_MAC_OVERRIDE in this way seems overly dangerous.
> If there were rules defined by the container, then I'd expect those to
> be overrideable - but not all rules pertaining to all labels mapped
> into the container.  But I guess based on  your envisioned usage (where
> I assume 'label1' is meant to *only* be used for that container) it
> might be ok.
>

CAP_MAC_OVERRIDE is only possible for labels that the admin explicitly
mapped. So it's up to him to decide what is dangerous or not. It can only
map labels that are not used outside of the container if it wishes to. But
the user himself will not be able to explot that without permission from
the admin.

So sorry this is not what you expected, but it seems that what you expected
is simply not feasible.


> thanks,
> -serge
>

Thanks,
Lukasz

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Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

Appologise for sending my previous email in HTML, this email address
was never meant to be used with lists. I resend in plain text.

On Wed, Jul 29, 2015 at 5:25 PM, Serge E. Hallyn <serge@hallyn.com> wrote:

>> +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.
>
> (Sorry it took me this long to get to reading, and thanks for working
> on this)
>
> Oh my.  All this is not at all what I'd expected :)
>
> Is there rationale for these decisions?  Hm, I guess it really is
> following the user_ns design, but the huge difference is that the
> user_ns is partitioning an already-enumerated set of kuids.  The
> smack labels are inherently different.

There is a big rationale for this. This is not to make Smack limit how
namespace can be created (this can be done separately, no conflict
here). This is to make Smack work at all inside a namespace. Please
note that contrary to SELinux and AppArmor Smack needs CAP_MAC_ADMIN
for it to operate on a normal basis. There is no rule for changing
labels. CAP_MAC_ADMIN is always required for this. And you cannot
unlock and give this capability just like that to anyone. Like in
every namespace you need a level of abstraction to allow an
unprivileged namespace to administer something.

> In containers, something we'd really like to be able to do is:
>
> Create a new container.  Just run it as label 'c1'.  Inside the
> container, let the admin install mysql from a package which assigns
> type 'mysqld', protecting the rest of the container from mysql.
> Without the host admin doing anything.
>
> Normally the way I think of implementing something like this would be
> to allow the host to say "c1 is to be namespaceable."  Then on a userns
> unshare, if the task is in c1, it gets transitioned into the ns.  Then the
> container sees c1 as _ (or whatever).  It can create 'mysql' which is
> actually 'c1.mysql' on the host, and it can create and override rules
> to c1.*.

Few things here.
1. Such an extension with using prefixes (with two exceptions, see
below) could be added to my patches. I even planned to do so (make a
prefix for a container and assign it a group of labels, this doesn't
conflict with arbitrary mapping). But this was refused by Casey on a
basis that by Smack defintion labels have no meaning. So no prefixes.
2. (expcetion #1) Changing any rules in a container has been deemed
too insecure at this point.
3. (expcetion #2) About the: "Without the host admin doing anything.".
With this namespace you delegate part of CAP_MAC_ADMIN privilege to an
unprivileged user (as with any other namespace). There is now way that
this will not involve host admin. The way you described it you allow
an unprivileged process to change its own label and change labels on a
filesystem. This is simply against Smack rules and completely
insecure. Even with user_ns if you map several UID you need admin
intervention.
>
> Also, allowing CAP_MAC_OVERRIDE in this way seems overly dangerous.
> If there were rules defined by the container, then I'd expect those to
> be overrideable - but not all rules pertaining to all labels mapped
> into the container.  But I guess based on  your envisioned usage (where
> I assume 'label1' is meant to *only* be used for that container) it
> might be ok.

CAP_MAC_OVERRIDE is only possible for labels that the admin explicitly
mapped. So it's up to him to decide what is dangerous or not. It can
only map labels that are not used outside of the container if it
wishes to. But the user himself will not be able to explot that
without permission from the admin.

So sorry this is not what you expected, but it seems that what you
expected is simply not feasible.

> thanks,
> -serge

Thanks,
Lukasz

Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

On Wed, Jul 29, 2015 at 6:13 PM, Lukasz Pawelczyk <havner@gmail.com> wrote:

> With this namespace you delegate part of CAP_MAC_ADMIN privilege to an
> unprivileged user (as with any other namespace).

Ok, maybe the part in the brackets is an overstatement. Mostly with
namespaces you create a full abstraction of some object and give user
priviledges to that object (e.g. uts structure, network interfaces,
with UTS and NET namespaces, etc). This is rather not possible with
Smack, as being a security module it has to retain its core security
paradigm.  It cannot be a separate LSM within a host LSM (remember the
part about changing process own label and changing any other object
label, mostly a file). So Smack namespace really as I see it has big
analogy to user namespace. You cannot abstract UIDs completely in a
namespace as those UIDs do live in a host as well. If you want to have
some capabilities over them, admin has to agree to that explicitly.

Thanks,
Lukasz

Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Serge E. Hallyn]

On Wed, Jul 29, 2015 at 06:13:59PM +0200, Lukasz Pawelczyk wrote:
> Appologise for sending my previous email in HTML, this email address
> was never meant to be used with lists. I resend in plain text.
> 
> On Wed, Jul 29, 2015 at 5:25 PM, Serge E. Hallyn <serge@hallyn.com> wrote:
> 
> >> +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.
> >
> > (Sorry it took me this long to get to reading, and thanks for working
> > on this)
> >
> > Oh my.  All this is not at all what I'd expected :)
> >
> > Is there rationale for these decisions?  Hm, I guess it really is
> > following the user_ns design, but the huge difference is that the
> > user_ns is partitioning an already-enumerated set of kuids.  The
> > smack labels are inherently different.
> 
> There is a big rationale for this. This is not to make Smack limit how
> namespace can be created (this can be done separately, no conflict
> here). This is to make Smack work at all inside a namespace. Please
> note that contrary to SELinux and AppArmor Smack needs CAP_MAC_ADMIN
> for it to operate on a normal basis. There is no rule for changing
> labels. CAP_MAC_ADMIN is always required for this. And you cannot
> unlock and give this capability just like that to anyone. Like in
> every namespace you need a level of abstraction to allow an
> unprivileged namespace to administer something.

Hm, ok - it's been a few years since I used smack, so I'll go back
and re-read the Documentation file first, then the doc patch and
this email again.

> > In containers, something we'd really like to be able to do is:
> >
> > Create a new container.  Just run it as label 'c1'.  Inside the
> > container, let the admin install mysql from a package which assigns
> > type 'mysqld', protecting the rest of the container from mysql.
> > Without the host admin doing anything.
> >
> > Normally the way I think of implementing something like this would be
> > to allow the host to say "c1 is to be namespaceable."  Then on a userns
> > unshare, if the task is in c1, it gets transitioned into the ns.  Then the
> > container sees c1 as _ (or whatever).  It can create 'mysql' which is
> > actually 'c1.mysql' on the host, and it can create and override rules
> > to c1.*.
> 
> Few things here.
> 1. Such an extension with using prefixes (with two exceptions, see
> below) could be added to my patches. I even planned to do so (make a
> prefix for a container and assign it a group of labels, this doesn't
> conflict with arbitrary mapping). But this was refused by Casey on a
> basis that by Smack defintion labels have no meaning. So no prefixes.

Ok, I'm hoping to discuss this with Casey at LSS.  I assume there will
be reasons why what I want is simply not possible, but I'd like to give
it a shot :)

One way around this might be to let the host admin say:

create smack labels c1_a1..c1_aN.  Map them into the container in a
way such that they have no name in the container yet.

Now when container admin says "create mysql_t", so long as there is
a not-yet-named mapped label, c1-aM, it gets mapped to the new name.

One hurdle to overcome there, of course, is how to reproduce that
mapping the next time we create this container.

Anyway, if this patchset is simply about making smack work in user_ns
at all, I'll reread with that in mind :)

> 2. (expcetion #1) Changing any rules in a container has been deemed
> too insecure at this point.
> 3. (expcetion #2) About the: "Without the host admin doing anything.".
> With this namespace you delegate part of CAP_MAC_ADMIN privilege to an
> unprivileged user (as with any other namespace). There is now way that
> this will not involve host admin. The way you described it you allow
> an unprivileged process to change its own label and change labels on a
> filesystem. This is simply against Smack rules and completely
> insecure. Even with user_ns if you map several UID you need admin
> intervention.
> >
> > Also, allowing CAP_MAC_OVERRIDE in this way seems overly dangerous.
> > If there were rules defined by the container, then I'd expect those to
> > be overrideable - but not all rules pertaining to all labels mapped
> > into the container.  But I guess based on  your envisioned usage (where
> > I assume 'label1' is meant to *only* be used for that container) it
> > might be ok.
> 
> CAP_MAC_OVERRIDE is only possible for labels that the admin explicitly
> mapped. So it's up to him to decide what is dangerous or not. It can
> only map labels that are not used outside of the container if it
> wishes to. But the user himself will not be able to explot that
> without permission from the admin.
> 
> So sorry this is not what you expected, but it seems that what you
> expected is simply not feasible.

-serge

Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Lukasz Pawelczyk]

Just a clarification, from my previous email:

> 3. (expcetion #2) About the: "Without the host admin doing anything.".
> With this namespace you delegate part of CAP_MAC_ADMIN privilege to an
> unprivileged user (as with any other namespace). There is now way that
> this will not involve host admin.

What I meant is: "There is NO way that this will not involve host admin."
Typo, sorry.

On Wed, Jul 29, 2015 at 6:37 PM, Serge E. Hallyn <serge@hallyn.com> wrote:

> Ok, I'm hoping to discuss this with Casey at LSS.  I assume there will
> be reasons why what I want is simply not possible, but I'd like to give
> it a shot :)
>
> One way around this might be to let the host admin say:
>
> create smack labels c1_a1..c1_aN.  Map them into the container in a
> way such that they have no name in the container yet.
>
> Now when container admin says "create mysql_t", so long as there is
> a not-yet-named mapped label, c1-aM, it gets mapped to the new name.

This by itself like I said would theoretically be possible (without
the "no admin intervention" and "modifying rules" parts). You mark the
container prefixed with something, let's say with "C1". Now any new
label you create inside a namespace will get automatic (implicit)
mapping:

C1-label -> label

Casey disliked the idea for these reasons (there was actually more
then one as I remember now):
1. What I said previously about special meaning for labels. The real
host label C1-label has a meaning now.
2. Labels have a specific max length. By prefixing them we reduce that
length, and it is pressumed to be true in several parts of the code.
3. This mechanic allows users to import labels, and as Smack doesn't
free or reuse them this is potentially DOS surface. Granted this is
technical limitation only that could be remedied at some point, but
for now the assumption that labels are not destroyed is taken
advantage of in several parts of the code to simplify the
implementation of Smack itself. (Mappings and mapped label structures
are freed with the end of life of user namespace).

> One hurdle to overcome there, of course, is how to reproduce that
> mapping the next time we create this container.

The name of the real label would hold the info (C1-label).

> Anyway, if this patchset is simply about making smack work in user_ns
> at all, I'll reread with that in mind :)

Would appreciate.

Thanks,
Lukasz

Re: [PATCH v3 11/11] smack: documentation for the Smack namespace

[Serge E. Hallyn]

On Wed, Jul 29, 2015 at 07:05:19PM +0200, Lukasz Pawelczyk wrote:
> > Anyway, if this patchset is simply about making smack work in user_ns
> > at all, I'll reread with that in mind :)
> 
> Would appreciate.

Ok - thanks for your patience.  I "get" it now.  Will go back to the
actual patches and review hopefully tonight and monday.

thanks,
-serge

Re: [PATCH v3 03/11] lsm: add file opener's cred to a setprocattr arguments

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:37PM +0200, Lukasz Pawelczyk wrote:
> setprocattr hook for Smack's label_map attribute needs to know the
> capabilities of file opener. Add those credentials to the hook's
> arguments.
> 
> While at it add documentation on get/setprocattr hooks.
> 
> Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> ---
>  fs/proc/base.c             |  2 +-
>  include/linux/lsm_hooks.h  | 18 ++++++++++++++++--
>  include/linux/security.h   |  7 +++++--
>  security/apparmor/lsm.c    |  5 +++--
>  security/security.c        |  6 ++++--
>  security/selinux/hooks.c   |  2 +-
>  security/smack/smack_lsm.c |  4 ++--
>  7 files changed, 32 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index e5ac827..775372c 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2458,7 +2458,7 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
>  	if (length < 0)
>  		goto out_free;
>  
> -	length = security_setprocattr(task,
> +	length = security_setprocattr(task, file->f_cred,
>  				      (char*)file->f_path.dentry->d_name.name,
>  				      (void*)page, count);
>  	mutex_unlock(&task->signal->cred_guard_mutex);
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index d347e66..1751864 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1220,6 +1220,20 @@
>   *	Return 0 if @name is to be handled by seq, EOPNOTSUPP if getprocattr()
>   *	should be used. Other errors will be passed to user-space.
>   *
> + * @getprocattr:
> + *	Get a value of a proc security attribute in /proc/$PID/attr/.
> + *	@p a task associated with the proc file.
> + *	@name a name of the file in question.
> + *	@value a pointer where to return the attribute's value.
> + *
> + * @setprocattr:
> + *	Set a value of a proc security attribute in /proc/$PID/attr/.
> + *	@p a task associated with the proc file.
> + *	@f_cred credentials of a file's opener.
> + *	@name a name of the file in question.
> + *	@value a pointer where a value to set is kept.
> + *	@size a number of bytes to read from the @value pointer.
> + *
>   * @secid_to_secctx:
>   *	Convert secid to security context.  If secdata is NULL the length of
>   *	the result will be returned in seclen, but no secdata will be returned.
> @@ -1540,8 +1554,8 @@ union security_list_options {
>  	int (*getprocattr_seq)(struct task_struct *p, const char *name,
>  			       const struct seq_operations **ops);
>  	int (*getprocattr)(struct task_struct *p, char *name, char **value);
> -	int (*setprocattr)(struct task_struct *p, char *name, void *value,
> -				size_t size);
> +	int (*setprocattr)(struct task_struct *p, const struct cred *f_cred,
> +			   char *name, void *value, size_t size);
>  	int (*ismaclabel)(const char *name);
>  	int (*secid_to_secctx)(u32 secid, char **secdata, u32 *seclen);
>  	int (*secctx_to_secid)(const char *secdata, u32 seclen, u32 *secid);
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 3090bb2..f0d2914 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -348,7 +348,8 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode);
>  int security_getprocattr_seq(struct task_struct *p, const char *name,
>  			     const struct seq_operations **ops);
>  int security_getprocattr(struct task_struct *p, char *name, char **value);
> -int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
> +int security_setprocattr(struct task_struct *p, const struct cred *f_cred,
> +			 char *name, void *value, size_t size);
>  int security_netlink_send(struct sock *sk, struct sk_buff *skb);
>  int security_ismaclabel(const char *name);
>  int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
> @@ -1071,7 +1072,9 @@ static inline int security_getprocattr(struct task_struct *p, char *name, char *
>  	return -EINVAL;
>  }
>  
> -static inline int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
> +static inline int security_setprocattr(struct task_struct *p,
> +				       const struct cred *f_cred,
> +				       char *name, void *value, size_t size)
>  {
>  	return -EINVAL;
>  }
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index dec607c..1212927 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -518,8 +518,9 @@ static int apparmor_getprocattr(struct task_struct *task, char *name,
>  	return error;
>  }
>  
> -static int apparmor_setprocattr(struct task_struct *task, char *name,
> -				void *value, size_t size)
> +static int apparmor_setprocattr(struct task_struct *task,
> +				const struct cred *f_cred,
> +				char *name, void *value, size_t size)
>  {
>  	struct common_audit_data sa;
>  	struct apparmor_audit_data aad = {0,};
> diff --git a/security/security.c b/security/security.c
> index e348e38..88a3b78 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1137,9 +1137,11 @@ int security_getprocattr(struct task_struct *p, char *name, char **value)
>  	return call_int_hook(getprocattr, -EINVAL, p, name, value);
>  }
>  
> -int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size)
> +int security_setprocattr(struct task_struct *p, const struct cred *f_cred,
> +			 char *name, void *value, size_t size)
>  {
> -	return call_int_hook(setprocattr, -EINVAL, p, name, value, size);
> +	return call_int_hook(setprocattr, -EINVAL, p, f_cred,
> +			     name, value, size);
>  }
>  
>  int security_netlink_send(struct sock *sk, struct sk_buff *skb)
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 564079c..3e1b9f7 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -5556,7 +5556,7 @@ invalid:
>  	return -EINVAL;
>  }
>  
> -static int selinux_setprocattr(struct task_struct *p,
> +static int selinux_setprocattr(struct task_struct *p, const struct cred *f_cred,
>  			       char *name, void *value, size_t size)
>  {
>  	struct task_security_struct *tsec;
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index d962f88..cdcabf4 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3450,8 +3450,8 @@ static int smack_getprocattr(struct task_struct *p, char *name, char **value)
>   *
>   * Returns the length of the smack label or an error code
>   */
> -static int smack_setprocattr(struct task_struct *p, char *name,
> -			     void *value, size_t size)
> +static int smack_setprocattr(struct task_struct *p, const struct cred *f_cred,
> +			     char *name, void *value, size_t size)
>  {
>  	struct task_smack *tsp;
>  	struct cred *new;
> -- 
> 2.4.3

Re: [PATCH v3 04/11] lsm: inode_pre_setxattr hook

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:38PM +0200, Lukasz Pawelczyk wrote:
> Add a new LSM hook called before inode's setxattr. It is required for
> LSM to be able to reliably replace the xattr's value to be set to
> filesystem in __vfs_setxattr_noperm(). Useful for mapped values, like in
> the upcoming Smack namespace patches.
> 
> Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

Could get confusing if userspace passes in 1 char and gets ENOSPC because
the unmapped label is too long :)

> ---
>  fs/xattr.c                | 10 ++++++++++
>  include/linux/lsm_hooks.h |  9 +++++++++
>  include/linux/security.h  | 10 ++++++++++
>  security/security.c       | 12 ++++++++++++
>  4 files changed, 41 insertions(+)
> 
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 072fee1..cbc8d19 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -100,12 +100,22 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
>  	if (issec)
>  		inode->i_flags &= ~S_NOSEC;
>  	if (inode->i_op->setxattr) {
> +		bool alloc = false;
> +
> +		error = security_inode_pre_setxattr(dentry, name, &value,
> +						    &size, flags, &alloc);
> +		if (error)
> +			return error;
> +
>  		error = inode->i_op->setxattr(dentry, name, value, size, flags);
>  		if (!error) {
>  			fsnotify_xattr(dentry);
>  			security_inode_post_setxattr(dentry, name, value,
>  						     size, flags);
>  		}
> +
> +		if (alloc)
> +			kfree(value);
>  	} else if (issec) {
>  		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
>  		error = security_inode_setsecurity(inode, suffix, value,
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 1751864..0aeed91 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -349,6 +349,11 @@
>   *	Check permission before setting the extended attributes
>   *	@value identified by @name for @dentry.
>   *	Return 0 if permission is granted.
> + * @inode_pre_setxattr:
> + *	Be able to do some operation before setting the @value identified
> + *	by @name on the filesystem. Replacing the @value and its @size is
> + *	possible. Useful for mapped values. Set @alloc to true if @value
> + *	needs to be kfreed afterwards.
>   * @inode_post_setxattr:
>   *	Update inode security field after successful setxattr operation.
>   *	@value identified by @name for @dentry.
> @@ -1448,6 +1453,9 @@ union security_list_options {
>  	int (*inode_getattr)(const struct path *path);
>  	int (*inode_setxattr)(struct dentry *dentry, const char *name,
>  				const void *value, size_t size, int flags);
> +	int (*inode_pre_setxattr)(struct dentry *dentry, const char *name,
> +				  const void **value, size_t *size,
> +				  int flags, bool *alloc);
>  	void (*inode_post_setxattr)(struct dentry *dentry, const char *name,
>  					const void *value, size_t size,
>  					int flags);
> @@ -1730,6 +1738,7 @@ struct security_hook_heads {
>  	struct list_head inode_setattr;
>  	struct list_head inode_getattr;
>  	struct list_head inode_setxattr;
> +	struct list_head inode_pre_setxattr;
>  	struct list_head inode_post_setxattr;
>  	struct list_head inode_getxattr;
>  	struct list_head inode_listxattr;
> diff --git a/include/linux/security.h b/include/linux/security.h
> index f0d2914..24f91e0 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -263,6 +263,9 @@ int security_inode_setattr(struct dentry *dentry, struct iattr *attr);
>  int security_inode_getattr(const struct path *path);
>  int security_inode_setxattr(struct dentry *dentry, const char *name,
>  			    const void *value, size_t size, int flags);
> +int security_inode_pre_setxattr(struct dentry *dentry, const char *name,
> +				const void **value, size_t *size, int flags,
> +				bool *alloc);
>  void security_inode_post_setxattr(struct dentry *dentry, const char *name,
>  				  const void *value, size_t size, int flags);
>  int security_inode_getxattr(struct dentry *dentry, const char *name);
> @@ -691,6 +694,13 @@ static inline int security_inode_setxattr(struct dentry *dentry,
>  	return cap_inode_setxattr(dentry, name, value, size, flags);
>  }
>  
> +static inline int security_inode_pre_setxattr(struct dentry *dentry,
> +				const char *name, const void **value,
> +				size_t *size, int flags, bool *alloc)
> +{
> +	return 0;
> +}
> +
>  static inline void security_inode_post_setxattr(struct dentry *dentry,
>  		const char *name, const void *value, size_t size, int flags)
>  { }
> diff --git a/security/security.c b/security/security.c
> index 88a3b78..e1d2c6f 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -649,6 +649,16 @@ int security_inode_setxattr(struct dentry *dentry, const char *name,
>  	return evm_inode_setxattr(dentry, name, value, size);
>  }
>  
> +int security_inode_pre_setxattr(struct dentry *dentry, const char *name,
> +				const void **value, size_t *size, int flags,
> +				bool *alloc)
> +{
> +	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> +		return 0;
> +	return call_int_hook(inode_pre_setxattr, 0, dentry, name, value, size,
> +			     flags, alloc);
> +}
> +
>  void security_inode_post_setxattr(struct dentry *dentry, const char *name,
>  				  const void *value, size_t size, int flags)
>  {
> @@ -1666,6 +1676,8 @@ struct security_hook_heads security_hook_heads = {
>  		LIST_HEAD_INIT(security_hook_heads.inode_getattr),
>  	.inode_setxattr =
>  		LIST_HEAD_INIT(security_hook_heads.inode_setxattr),
> +	.inode_pre_setxattr =
> +		LIST_HEAD_INIT(security_hook_heads.inode_pre_setxattr),
>  	.inode_post_setxattr =
>  		LIST_HEAD_INIT(security_hook_heads.inode_post_setxattr),
>  	.inode_getxattr =
> -- 
> 2.4.3

Re: [PATCH v3 04/11] lsm: inode_pre_setxattr hook

[Lukasz Pawelczyk]

On czw, 2015-07-30 at 16:56 -0500, Serge E. Hallyn wrote:
> On Fri, Jul 24, 2015 at 12:04:38PM +0200, Lukasz Pawelczyk wrote:
> > Add a new LSM hook called before inode's setxattr. It is required 
> > for
> > LSM to be able to reliably replace the xattr's value to be set to
> > filesystem in __vfs_setxattr_noperm(). Useful for mapped values, 
> > like in
> > the upcoming Smack namespace patches.
> > 
> > Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
> 
> Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
> 
> Could get confusing if userspace passes in 1 char and gets ENOSPC 
> because
> the unmapped label is too long :)

I would consider such a case a bug in LSM module. If there exists a
mapping "very_very_long_label" -> "l" the module needs to know that the
very long label is possible to get written. After all it would be
written on the host directly.

Smack has a limit for max label name and importing longer label (which
also means creating a mapping with a longer label) will get refused.

At least that's my understanding, but thanks, that's an interesting
remark :-)

> 
> > ---
> >  fs/xattr.c                | 10 ++++++++++
> >  include/linux/lsm_hooks.h |  9 +++++++++
> >  include/linux/security.h  | 10 ++++++++++
> >  security/security.c       | 12 ++++++++++++
> >  4 files changed, 41 insertions(+)
> > 
> > diff --git a/fs/xattr.c b/fs/xattr.c
> > index 072fee1..cbc8d19 100644
> > --- a/fs/xattr.c
> > +++ b/fs/xattr.c
> > @@ -100,12 +100,22 @@ int __vfs_setxattr_noperm(struct dentry 
> > *dentry, const char *name,
> >  	if (issec)
> >  		inode->i_flags &= ~S_NOSEC;
> >  	if (inode->i_op->setxattr) {
> > +		bool alloc = false;
> > +
> > +		error = security_inode_pre_setxattr(dentry, name, 
> > &value,
> > +						    &size, flags, 
> > &alloc);
> > +		if (error)
> > +			return error;
> > +
> >  		error = inode->i_op->setxattr(dentry, name, value, 
> > size, flags);
> >  		if (!error) {
> >  			fsnotify_xattr(dentry);
> >  			security_inode_post_setxattr(dentry, name, 
> > value,
> >  						     size, flags);
> >  		}
> > +
> > +		if (alloc)
> > +			kfree(value);
> >  	} else if (issec) {
> >  		const char *suffix = name + 
> > XATTR_SECURITY_PREFIX_LEN;
> >  		error = security_inode_setsecurity(inode, suffix, 
> > value,
> > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> > index 1751864..0aeed91 100644
> > --- a/include/linux/lsm_hooks.h
> > +++ b/include/linux/lsm_hooks.h
> > @@ -349,6 +349,11 @@
> >   *	Check permission before setting the extended attributes
> >   *	@value identified by @name for @dentry.
> >   *	Return 0 if permission is granted.
> > + * @inode_pre_setxattr:
> > + *	Be able to do some operation before setting the @value 
> > identified
> > + *	by @name on the filesystem. Replacing the @value and its 
> > @size is
> > + *	possible. Useful for mapped values. Set @alloc to true 
> > if @value
> > + *	needs to be kfreed afterwards.
> >   * @inode_post_setxattr:
> >   *	Update inode security field after successful setxattr 
> > operation.
> >   *	@value identified by @name for @dentry.
> > @@ -1448,6 +1453,9 @@ union security_list_options {
> >  	int (*inode_getattr)(const struct path *path);
> >  	int (*inode_setxattr)(struct dentry *dentry, const char 
> > *name,
> >  				const void *value, size_t size, 
> > int flags);
> > +	int (*inode_pre_setxattr)(struct dentry *dentry, const 
> > char *name,
> > +				  const void **value, size_t 
> > *size,
> > +				  int flags, bool *alloc);
> >  	void (*inode_post_setxattr)(struct dentry *dentry, const 
> > char *name,
> >  					const void *value, size_t 
> > size,
> >  					int flags);
> > @@ -1730,6 +1738,7 @@ struct security_hook_heads {
> >  	struct list_head inode_setattr;
> >  	struct list_head inode_getattr;
> >  	struct list_head inode_setxattr;
> > +	struct list_head inode_pre_setxattr;
> >  	struct list_head inode_post_setxattr;
> >  	struct list_head inode_getxattr;
> >  	struct list_head inode_listxattr;
> > diff --git a/include/linux/security.h b/include/linux/security.h
> > index f0d2914..24f91e0 100644
> > --- a/include/linux/security.h
> > +++ b/include/linux/security.h
> > @@ -263,6 +263,9 @@ int security_inode_setattr(struct dentry 
> > *dentry, struct iattr *attr);
> >  int security_inode_getattr(const struct path *path);
> >  int security_inode_setxattr(struct dentry *dentry, const char 
> > *name,
> >  			    const void *value, size_t size, int 
> > flags);
> > +int security_inode_pre_setxattr(struct dentry *dentry, const char 
> > *name,
> > +				const void **value, size_t *size, 
> > int flags,
> > +				bool *alloc);
> >  void security_inode_post_setxattr(struct dentry *dentry, const 
> > char *name,
> >  				  const void *value, size_t size, 
> > int flags);
> >  int security_inode_getxattr(struct dentry *dentry, const char 
> > *name);
> > @@ -691,6 +694,13 @@ static inline int 
> > security_inode_setxattr(struct dentry *dentry,
> >  	return cap_inode_setxattr(dentry, name, value, size, 
> > flags);
> >  }
> >  
> > +static inline int security_inode_pre_setxattr(struct dentry 
> > *dentry,
> > +				const char *name, const void 
> > **value,
> > +				size_t *size, int flags, bool 
> > *alloc)
> > +{
> > +	return 0;
> > +}
> > +
> >  static inline void security_inode_post_setxattr(struct dentry 
> > *dentry,
> >  		const char *name, const void *value, size_t size, 
> > int flags)
> >  { }
> > diff --git a/security/security.c b/security/security.c
> > index 88a3b78..e1d2c6f 100644
> > --- a/security/security.c
> > +++ b/security/security.c
> > @@ -649,6 +649,16 @@ int security_inode_setxattr(struct dentry 
> > *dentry, const char *name,
> >  	return evm_inode_setxattr(dentry, name, value, size);
> >  }
> >  
> > +int security_inode_pre_setxattr(struct dentry *dentry, const char 
> > *name,
> > +				const void **value, size_t *size, 
> > int flags,
> > +				bool *alloc)
> > +{
> > +	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> > +		return 0;
> > +	return call_int_hook(inode_pre_setxattr, 0, dentry, name, 
> > value, size,
> > +			     flags, alloc);
> > +}
> > +
> >  void security_inode_post_setxattr(struct dentry *dentry, const 
> > char *name,
> >  				  const void *value, size_t size, 
> > int flags)
> >  {
> > @@ -1666,6 +1676,8 @@ struct security_hook_heads 
> > security_hook_heads = {
> >  		LIST_HEAD_INIT(security_hook_heads.inode_getattr),
> >  	.inode_setxattr =
> >  		LIST_HEAD_INIT(security_hook_heads.inode_setxattr)
> > ,
> > +	.inode_pre_setxattr =
> > +		LIST_HEAD_INIT(security_hook_heads.inode_pre_setxa
> > ttr),
> >  	.inode_post_setxattr =
> >  		LIST_HEAD_INIT(security_hook_heads.inode_post_setx
> > attr),
> >  	.inode_getxattr =
-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v3 05/11] smack: extend capability functions and fix 2 checks

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:39PM +0200, Lukasz Pawelczyk wrote:
> 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@samsung.com>
> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> ---
>  security/smack/smack.h        |  5 ++++
>  security/smack/smack_access.c | 64 +++++++++++++++++++++++++++++++++++++++----
>  security/smack/smack_lsm.c    |  4 +--
>  3 files changed, 65 insertions(+), 8 deletions(-)
> 
> diff --git a/security/smack/smack.h b/security/smack/smack.h
> index 69ab9eb..e11cc13 100644
> --- a/security/smack/smack.h
> +++ b/security/smack/smack.h
> @@ -272,6 +272,11 @@ 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 *);
> +int smack_has_ns_privilege(struct task_struct *task,
> +			   struct user_namespace *user_ns,
> +			   int cap);
> +int smack_has_privilege(struct task_struct *task, int cap);
> +int smack_ns_privileged(struct user_namespace *user_ns, int cap);
>  int smack_privileged(int cap);
>  
>  /*
> diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
> index 00f6b38..188b354 100644
> --- a/security/smack/smack_access.c
> +++ b/security/smack/smack_access.c
> @@ -629,17 +629,19 @@ LIST_HEAD(smack_onlycap_list);
>  DEFINE_MUTEX(smack_onlycap_lock);
>  
>  /*
> - * Is the task privileged and allowed to be privileged
> - * by the onlycap rule.
> + * Internal smack capability check complimentary to the
> + * set of kernel capable() and has_capability() functions
>   *
> - * Returns 1 if the task is allowed to be privileged, 0 if it's not.
> + * For a capability in smack related checks to be effective it needs to:
> + * - be allowed to be privileged by the onlycap rule.
> + * - be in the initial user ns
>   */
> -int smack_privileged(int cap)
> +static int smack_capability_allowed(struct smack_known *skp,
> +				    struct user_namespace *user_ns)
>  {
> -	struct smack_known *skp = smk_of_current();
>  	struct smack_onlycap *sop;
>  
> -	if (!capable(cap))
> +	if (user_ns != &init_user_ns)
>  		return 0;
>  
>  	rcu_read_lock();
> @@ -658,3 +660,53 @@ int smack_privileged(int cap)
>  
>  	return 0;
>  }
> +
> +/*
> + * Is the task privileged in a namespace and allowed to be privileged
> + * by additional smack rules.
> + */
> +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 additional smack rules.
> + */
> +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.
> + */
> +int smack_ns_privileged(struct user_namespace *user_ns, int cap)
> +{
> +	struct smack_known *skp = smk_of_current();
> +
> +	if (!ns_capable(user_ns, cap))
> +		return 0;
> +	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.
> + */
> +int smack_privileged(int cap)
> +{
> +	return smack_ns_privileged(&init_user_ns, cap);
> +}
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index cdcabf4..6098518 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -413,7 +413,7 @@ 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;
> @@ -1805,7 +1805,7 @@ 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);
> -- 
> 2.4.3

Re: [PATCH v3 06/11] smack: don't use implicit star to display smackfs/syslog

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:40PM +0200, Lukasz Pawelczyk wrote:
> Smackfs/syslog is analogous to onlycap and unconfined. When not filled
> they don't do anything. In such cases onlycap and unconfined displayed
> nothing when read, but syslog unconditionally displayed star. This
> doesn't work well with namespaces where the star could have been
> unmapped. Besides the meaning of this star was different then a star
> that could be written to this file. This was misleading.
> 
> This also brings syslog read/write functions on par with onlycap and
> unconfined where it is possible to reset the value to NULL as should be
> possible according to comment in smackfs.c describing smack_syslog_label
> variable.
> 
> Before that the initial state was to allow (smack_syslog_label was
> NULL), but after writing star to it the current had to be labeled star
> as well to have an access, even thought reading the smackfs/syslog
> returned the same result in both cases.
> 
> Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> ---
>  security/smack/smackfs.c | 42 +++++++++++++++++++++++++++---------------
>  1 file changed, 27 insertions(+), 15 deletions(-)
> 
> diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
> index 81a2888..89f847bba 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -2362,23 +2362,20 @@ 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;
> +	char *smack = "";
>  	ssize_t rc = -EINVAL;
>  	int asize;
>  
>  	if (*ppos != 0)
>  		return 0;
>  
> -	if (smack_syslog_label == NULL)
> -		skp = &smack_known_star;
> -	else
> -		skp = smack_syslog_label;
> +	if (smack_syslog_label != NULL)
> +		smack = smack_syslog_label->smk_known;
>  
> -	asize = strlen(skp->smk_known) + 1;
> +	asize = strlen(smack) + 1;
>  
>  	if (cn >= asize)
> -		rc = simple_read_from_buffer(buf, cn, ppos, skp->smk_known,
> -						asize);
> +		rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);
>  
>  	return rc;
>  }
> @@ -2406,16 +2403,31 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
>  	if (data == NULL)
>  		return -ENOMEM;
>  
> -	if (copy_from_user(data, buf, count) != 0)
> +	if (copy_from_user(data, buf, count) != 0) {
>  		rc = -EFAULT;
> -	else {
> -		skp = smk_import_entry(data, count);
> -		if (IS_ERR(skp))
> -			rc = PTR_ERR(skp);
> -		else
> -			smack_syslog_label = skp;
> +		goto freeout;
>  	}
>  
> +	/*
> +	 * Clear the smack_syslog_label on invalid label errors. This means
> +	 * that we can pass a null string to unset the syslog value.
> +	 *
> +	 * Importing will also reject a label beginning with '-',
> +	 * so "-syslog" will also work.
> +	 *
> +	 * But do so only on invalid label, not on system errors.
> +	 */
> +	skp = smk_import_entry(data, count);
> +	if (PTR_ERR(skp) == -EINVAL)
> +		skp = NULL;
> +	else if (IS_ERR(skp)) {
> +		rc = PTR_ERR(skp);
> +		goto freeout;
> +	}
> +
> +	smack_syslog_label = skp;
> +
> +freeout:
>  	kfree(data);
>  	return rc;
>  }
> -- 
> 2.4.3

Re: [PATCH v3 02/11] lsm: /proc/$PID/attr/label_map file and getprocattr_seq hook

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:36PM +0200, Lukasz Pawelczyk wrote:
> This commit adds a new proc attribute, label_map that is required by an
> upcoming Smack namespace. In general it can be used to hold a map of
> labels, e.g. to be used in namespaces.
> 
> Due to the nature of this file, the standard getprocattr hook might not
> be enough to handle it. The map's output can in principle be greater
> than page size to which the aforementioned hook is limited.
> To handle this properly a getprocattr_seq LSM hook has been added that
> makes it possible to handle any chosen proc attr by seq operations.
> 
> See the documentation in the patch below for the details about how to
> use the hook.
> 
> Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> ---
>  fs/proc/base.c            | 81 +++++++++++++++++++++++++++++++++++++++++++----
>  include/linux/lsm_hooks.h | 15 +++++++++
>  include/linux/security.h  |  9 ++++++
>  security/security.c       |  8 +++++
>  4 files changed, 107 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index aa50d1a..e5ac827 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2338,20 +2338,77 @@ out:
>  }
>  
>  #ifdef CONFIG_SECURITY
> +static int proc_pid_attr_open(struct inode *inode, struct file *file)
> +{
> +	const char *name = file->f_path.dentry->d_name.name;
> +	const struct seq_operations *ops;
> +	struct task_struct *task;
> +	struct seq_file *seq;
> +	int ret;
> +
> +	file->private_data = NULL;
> +
> +	task = get_proc_task(inode);
> +	if (!task)
> +		return -ESRCH;
> +
> +	/* don't use seq_ops if they are not provided by LSM */
> +	ret = security_getprocattr_seq(task, name, &ops);
> +	if (ret == -EOPNOTSUPP) {
> +		put_task_struct(task);
> +		return 0;
> +	}
> +	if (ret) {
> +		put_task_struct(task);
> +		return ret;
> +	}
> +
> +	ret = seq_open(file, ops);
> +	if (ret) {
> +		put_task_struct(task);
> +		return ret;
> +	}
> +
> +	seq = file->private_data;
> +	seq->private = task;
> +
> +	return 0;
> +}
> +
> +static int proc_pid_attr_release(struct inode *inode, struct file *file)
> +{
> +	struct seq_file *seq;
> +	struct task_struct *task;
> +
> +	/* don't use seq_ops if they were not provided by LSM */
> +	if (file->private_data == NULL)
> +		return 0;
> +
> +	seq = file->private_data;
> +	task = seq->private;
> +	put_task_struct(task);
> +
> +	return seq_release(inode, file);
> +}
> +
>  static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
>  				  size_t count, loff_t *ppos)
>  {
> -	struct inode * inode = file_inode(file);
> +	struct inode *inode = file_inode(file);
> +	const char *name = file->f_path.dentry->d_name.name;
>  	char *p = NULL;
>  	ssize_t length;
> -	struct task_struct *task = get_proc_task(inode);
> +	struct task_struct *task;
> +
> +	/* use seq_ops if they were provided by LSM */
> +	if (file->private_data)
> +		return seq_read(file, buf, count, ppos);
>  
> +	task = get_proc_task(inode);
>  	if (!task)
>  		return -ESRCH;
>  
> -	length = security_getprocattr(task,
> -				      (char*)file->f_path.dentry->d_name.name,
> -				      &p);
> +	length = security_getprocattr(task, (char *)name, &p);
>  	put_task_struct(task);
>  	if (length > 0)
>  		length = simple_read_from_buffer(buf, count, ppos, p, length);
> @@ -2359,6 +2416,15 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf,
>  	return length;
>  }
>  
> +static loff_t proc_pid_attr_lseek(struct file *file, loff_t offset, int whence)
> +{
> +	/* use seq_ops if they were provided by LSM */
> +	if (file->private_data)
> +		return seq_lseek(file, offset, whence);
> +
> +	return generic_file_llseek(file, offset, whence);
> +}
> +
>  static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf,
>  				   size_t count, loff_t *ppos)
>  {
> @@ -2405,9 +2471,11 @@ out_no_task:
>  }
>  
>  static const struct file_operations proc_pid_attr_operations = {
> +	.open		= proc_pid_attr_open,
> +	.release	= proc_pid_attr_release,
>  	.read		= proc_pid_attr_read,
> +	.llseek		= proc_pid_attr_lseek,
>  	.write		= proc_pid_attr_write,
> -	.llseek		= generic_file_llseek,
>  };
>  
>  static const struct pid_entry attr_dir_stuff[] = {
> @@ -2417,6 +2485,7 @@ static const struct pid_entry attr_dir_stuff[] = {
>  	REG("fscreate",   S_IRUGO|S_IWUGO, proc_pid_attr_operations),
>  	REG("keycreate",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
>  	REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations),
> +	REG("label_map",  S_IRUGO|S_IWUGO, proc_pid_attr_operations),
>  };
>  
>  static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx)
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 228558c..d347e66 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1208,6 +1208,18 @@
>   *	@name full extended attribute name to check against
>   *	LSM as a MAC label.
>   *
> + * @getprocattr_seq:
> + *	An alternative to the getprocattr, that makes it possible for an attr
> + *	file to be handled by seq operations. If this function returns valid
> + *	@ops for a specific @name, those operations will be used and
> + *	getprocattr will not be called.
> + *	A proper task for the file is then passed in seq_file->private.
> + *	@p a task associated with the proc file.
> + *	@name name of the attr file under /proc/$PID/attr/ to be handled.
> + *	@ops (out) seq_operations to be used for @name.
> + *	Return 0 if @name is to be handled by seq, EOPNOTSUPP if getprocattr()
> + *	should be used. Other errors will be passed to user-space.
> + *
>   * @secid_to_secctx:
>   *	Convert secid to security context.  If secdata is NULL the length of
>   *	the result will be returned in seclen, but no secdata will be returned.
> @@ -1525,6 +1537,8 @@ union security_list_options {
>  
>  	void (*d_instantiate)(struct dentry *dentry, struct inode *inode);
>  
> +	int (*getprocattr_seq)(struct task_struct *p, const char *name,
> +			       const struct seq_operations **ops);
>  	int (*getprocattr)(struct task_struct *p, char *name, char **value);
>  	int (*setprocattr)(struct task_struct *p, char *name, void *value,
>  				size_t size);
> @@ -1774,6 +1788,7 @@ struct security_hook_heads {
>  	struct list_head sem_semop;
>  	struct list_head netlink_send;
>  	struct list_head d_instantiate;
> +	struct list_head getprocattr_seq;
>  	struct list_head getprocattr;
>  	struct list_head setprocattr;
>  	struct list_head ismaclabel;
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 1b0eccc..3090bb2 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -345,6 +345,8 @@ int security_sem_semctl(struct sem_array *sma, int cmd);
>  int security_sem_semop(struct sem_array *sma, struct sembuf *sops,
>  			unsigned nsops, int alter);
>  void security_d_instantiate(struct dentry *dentry, struct inode *inode);
> +int security_getprocattr_seq(struct task_struct *p, const char *name,
> +			     const struct seq_operations **ops);
>  int security_getprocattr(struct task_struct *p, char *name, char **value);
>  int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size);
>  int security_netlink_send(struct sock *sk, struct sk_buff *skb);
> @@ -1057,6 +1059,13 @@ static inline int security_sem_semop(struct sem_array *sma,
>  static inline void security_d_instantiate(struct dentry *dentry, struct inode *inode)
>  { }
>  
> +static inline int security_getprocattr_seq(struct task_struct *p,
> +					   const char *name,
> +					   const struct seq_operations **ops)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
>  static inline int security_getprocattr(struct task_struct *p, char *name, char **value)
>  {
>  	return -EINVAL;
> diff --git a/security/security.c b/security/security.c
> index 5e66388..e348e38 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -1126,6 +1126,12 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode)
>  }
>  EXPORT_SYMBOL(security_d_instantiate);
>  
> +int security_getprocattr_seq(struct task_struct *p, const char *name,
> +			     const struct seq_operations **ops)
> +{
> +	return call_int_hook(getprocattr_seq, -EOPNOTSUPP, p, name, ops);
> +}
> +
>  int security_getprocattr(struct task_struct *p, char *name, char **value)
>  {
>  	return call_int_hook(getprocattr, -EINVAL, p, name, value);
> @@ -1778,6 +1784,8 @@ struct security_hook_heads security_hook_heads = {
>  	.netlink_send =	LIST_HEAD_INIT(security_hook_heads.netlink_send),
>  	.d_instantiate =
>  		LIST_HEAD_INIT(security_hook_heads.d_instantiate),
> +	.getprocattr_seq =
> +		LIST_HEAD_INIT(security_hook_heads.getprocattr_seq),
>  	.getprocattr =	LIST_HEAD_INIT(security_hook_heads.getprocattr),
>  	.setprocattr =	LIST_HEAD_INIT(security_hook_heads.setprocattr),
>  	.ismaclabel =	LIST_HEAD_INIT(security_hook_heads.ismaclabel),
> -- 
> 2.4.3

Re: [PATCH v3 02/11] lsm: /proc/$PID/attr/label_map file and getprocattr_seq hook

[Paul Moore]

On Fri, Jul 24, 2015 at 6:04 AM, Lukasz Pawelczyk
<l.pawelczyk@samsung.com> wrote:
> This commit adds a new proc attribute, label_map that is required by an
> upcoming Smack namespace. In general it can be used to hold a map of
> labels, e.g. to be used in namespaces.
>
> Due to the nature of this file, the standard getprocattr hook might not
> be enough to handle it. The map's output can in principle be greater
> than page size to which the aforementioned hook is limited.
> To handle this properly a getprocattr_seq LSM hook has been added that
> makes it possible to handle any chosen proc attr by seq operations.
>
> See the documentation in the patch below for the details about how to
> use the hook.
>
> Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
> ---
>  fs/proc/base.c            | 81 +++++++++++++++++++++++++++++++++++++++++++----
>  include/linux/lsm_hooks.h | 15 +++++++++
>  include/linux/security.h  |  9 ++++++
>  security/security.c       |  8 +++++
>  4 files changed, 107 insertions(+), 6 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index aa50d1a..e5ac827 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -2338,20 +2338,77 @@ out:
>  }
>
>  #ifdef CONFIG_SECURITY
> +static int proc_pid_attr_open(struct inode *inode, struct file *file)
> +{
> +       const char *name = file->f_path.dentry->d_name.name;
> +       const struct seq_operations *ops;
> +       struct task_struct *task;
> +       struct seq_file *seq;
> +       int ret;
> +
> +       file->private_data = NULL;
> +
> +       task = get_proc_task(inode);
> +       if (!task)
> +               return -ESRCH;
> +
> +       /* don't use seq_ops if they are not provided by LSM */
> +       ret = security_getprocattr_seq(task, name, &ops);
> +       if (ret == -EOPNOTSUPP) {
> +               put_task_struct(task);
> +               return 0;
> +       }
> +       if (ret) {
> +               put_task_struct(task);
> +               return ret;
> +       }
> +
> +       ret = seq_open(file, ops);
> +       if (ret) {
> +               put_task_struct(task);
> +               return ret;
> +       }
> +
> +       seq = file->private_data;
> +       seq->private = task;
> +
> +       return 0;
> +}

If you end up having to respin this patchset, you might consider
moving the "put_task_struct(...); return X;" code into a block at the
end of the function to simplify things a bit, for example:

static int proc_pid_attr_open(struct inode *inode, struct file *file)
{
       const char *name = file->f_path.dentry->d_name.name;
       const struct seq_operations *ops;
       struct task_struct *task;
       struct seq_file *seq;
       int ret;

       file->private_data = NULL;

       task = get_proc_task(inode);
       if (!task)
               return -ESRCH;

       /* don't use seq_ops if they are not provided by LSM */
       ret = security_getprocattr_seq(task, name, &ops);
       if (ret == -EOPNOTSUPP) {
               ret = 0;
               goto put_task;
       }
       if (ret)
               goto put_task;

       ret = seq_open(file, ops);
       if (ret)
               goto put_task;

       seq = file->private_data;
       seq->private = task;

       return 0;

put_task:
       put_task_struct(task);
       return ret;
}

-- 
paul moore
www.paul-moore.com

Re: [PATCH v3 02/11] lsm: /proc/$PID/attr/label_map file and getprocattr_seq hook

[Lukasz Pawelczyk]

On pią, 2015-08-21 at 01:14 -0400, Paul Moore wrote:
> On Fri, Jul 24, 2015 at 6:04 AM, Lukasz Pawelczyk
> <l.pawelczyk@samsung.com> wrote:
> > This commit adds a new proc attribute, label_map that is required 
> > by an
> > upcoming Smack namespace. In general it can be used to hold a map 
> > of
> > labels, e.g. to be used in namespaces.
> > 
> > Due to the nature of this file, the standard getprocattr hook might 
> > not
> > be enough to handle it. The map's output can in principle be 
> > greater
> > than page size to which the aforementioned hook is limited.
> > To handle this properly a getprocattr_seq LSM hook has been added 
> > that
> > makes it possible to handle any chosen proc attr by seq operations.
> > 
> > See the documentation in the patch below for the details about how 
> > to
> > use the hook.
> > 
> > Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
> > ---
> >  fs/proc/base.c            | 81 
> > +++++++++++++++++++++++++++++++++++++++++++----
> >  include/linux/lsm_hooks.h | 15 +++++++++
> >  include/linux/security.h  |  9 ++++++
> >  security/security.c       |  8 +++++
> >  4 files changed, 107 insertions(+), 6 deletions(-)
> > 
> > diff --git a/fs/proc/base.c b/fs/proc/base.c
> > index aa50d1a..e5ac827 100644
> > --- a/fs/proc/base.c
> > +++ b/fs/proc/base.c
> > @@ -2338,20 +2338,77 @@ out:
> >  }
> > 
> >  #ifdef CONFIG_SECURITY
> > +static int proc_pid_attr_open(struct inode *inode, struct file 
> > *file)
> > +{
> > +       const char *name = file->f_path.dentry->d_name.name;
> > +       const struct seq_operations *ops;
> > +       struct task_struct *task;
> > +       struct seq_file *seq;
> > +       int ret;
> > +
> > +       file->private_data = NULL;
> > +
> > +       task = get_proc_task(inode);
> > +       if (!task)
> > +               return -ESRCH;
> > +
> > +       /* don't use seq_ops if they are not provided by LSM */
> > +       ret = security_getprocattr_seq(task, name, &ops);
> > +       if (ret == -EOPNOTSUPP) {
> > +               put_task_struct(task);
> > +               return 0;
> > +       }
> > +       if (ret) {
> > +               put_task_struct(task);
> > +               return ret;
> > +       }
> > +
> > +       ret = seq_open(file, ops);
> > +       if (ret) {
> > +               put_task_struct(task);
> > +               return ret;
> > +       }
> > +
> > +       seq = file->private_data;
> > +       seq->private = task;
> > +
> > +       return 0;
> > +}
> 
> If you end up having to respin this patchset, you might consider
> moving the "put_task_struct(...); return X;" code into a block at the
> end of the function to simplify things a bit, for example:

I will do so, thanks.

> 
> static int proc_pid_attr_open(struct inode *inode, struct file *file)
> {
>        const char *name = file->f_path.dentry->d_name.name;
>        const struct seq_operations *ops;
>        struct task_struct *task;
>        struct seq_file *seq;
>        int ret;
> 
>        file->private_data = NULL;
> 
>        task = get_proc_task(inode);
>        if (!task)
>                return -ESRCH;
> 
>        /* don't use seq_ops if they are not provided by LSM */
>        ret = security_getprocattr_seq(task, name, &ops);
>        if (ret == -EOPNOTSUPP) {
>                ret = 0;
>                goto put_task;
>        }
>        if (ret)
>                goto put_task;
> 
>        ret = seq_open(file, ops);
>        if (ret)
>                goto put_task;
> 
>        seq = file->private_data;
>        seq->private = task;
> 
>        return 0;
> 
> put_task:
>        put_task_struct(task);
>        return ret;
> }
> 
-- 
Lukasz Pawelczyk
Samsung R&D Institute Poland
Samsung Electronics

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Serge E. Hallyn]

On Fri, Jul 24, 2015 at 12:04:35PM +0200, Lukasz Pawelczyk wrote:
> 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@samsung.com>
> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
>  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 9429f05..228558c 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1261,6 +1261,23 @@
>   *	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 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
> @@ -1613,6 +1630,12 @@ union security_list_options {
>  				struct audit_context *actx);
>  	void (*audit_rule_free)(void *lsmrule);
>  #endif /* CONFIG_AUDIT */
> +
> +#ifdef CONFIG_USER_NS
> +	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_USER_NS */
>  };
>  
>  struct security_hook_heads {
> @@ -1824,6 +1847,11 @@ struct security_hook_heads {
>  	struct list_head audit_rule_match;
>  	struct list_head audit_rule_free;
>  #endif /* CONFIG_AUDIT */
> +#ifdef CONFIG_USER_NS
> +	struct list_head userns_create;
> +	struct list_head userns_free;
> +	struct list_head userns_setns;
> +#endif /* CONFIG_USER_NS */
>  };
>  
>  /*
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 79d85dd..1b0eccc 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -1584,6 +1584,29 @@ static inline void security_audit_rule_free(void *lsmrule)
>  #endif /* CONFIG_SECURITY */
>  #endif /* CONFIG_AUDIT */
>  
> +#ifdef CONFIG_USER_NS
> +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_USER_NS */
> +
>  #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;

So at this point the LSM thinks current is in the new ns.  If
prepare_creds() fails below, should it be informed of that?
(Or am I over-thinking this?)

> +
>  	cred = prepare_creds();
>  	if (!cred)
>  		return -ENOMEM;
> diff --git a/security/security.c b/security/security.c
> index 595fffa..5e66388 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
> @@ -1542,6 +1543,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
>  }
>  #endif /* CONFIG_AUDIT */
>  
> +#ifdef CONFIG_USER_NS
> +
> +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_USER_NS */
> +
>  struct security_hook_heads security_hook_heads = {
>  	.binder_set_context_mgr =
>  		LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr),
> @@ -1886,4 +1906,12 @@ struct security_hook_heads security_hook_heads = {
>  	.audit_rule_free =
>  		LIST_HEAD_INIT(security_hook_heads.audit_rule_free),
>  #endif /* CONFIG_AUDIT */
> +#ifdef CONFIG_USER_NS
> +	.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_USER_NS */
>  };
> -- 
> 2.4.3

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Lukasz Pawelczyk]

On czw, 2015-07-30 at 16:30 -0500, Serge E. Hallyn wrote:
> On Fri, Jul 24, 2015 at 12:04:35PM +0200, Lukasz Pawelczyk wrote:
> > @@ -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;
> 
> So at this point the LSM thinks current is in the new ns.  If
> prepare_creds() fails below, should it be informed of that?
> (Or am I over-thinking this?)
> 
> > +
> >  	cred = prepare_creds();
> >  	if (!cred)
> >  		return -ENOMEM;

Hmm, the use case for this hook I had in mind was just to allow or
disallow the operation based on the information passed in arguments.
Not to register the current in any way so LSM can think it is or isn't
in the new namespace.

I think that any other LSM check that would like to know in what
namespace the current is, would just check that from current's creds.
Not use some stale and duplicated information the above hook could have
registered.

I see no reason for this hook to change the LSM state, only to answer
the question: allowed/disallowed (eventually return an error cause it
is unable to give an answer which falls into the disallow category).


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

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Serge E. Hallyn]

On Fri, Jul 31, 2015 at 11:28:56AM +0200, Lukasz Pawelczyk wrote:
> On czw, 2015-07-30 at 16:30 -0500, Serge E. Hallyn wrote:
> > On Fri, Jul 24, 2015 at 12:04:35PM +0200, Lukasz Pawelczyk wrote:
> > > @@ -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;
> > 
> > So at this point the LSM thinks current is in the new ns.  If
> > prepare_creds() fails below, should it be informed of that?
> > (Or am I over-thinking this?)
> > 
> > > +
> > >  	cred = prepare_creds();
> > >  	if (!cred)
> > >  		return -ENOMEM;
> 
> Hmm, the use case for this hook I had in mind was just to allow or
> disallow the operation based on the information passed in arguments.
> Not to register the current in any way so LSM can think it is or isn't
> in the new namespace.
> 
> I think that any other LSM check that would like to know in what
> namespace the current is, would just check that from current's creds.
> Not use some stale and duplicated information the above hook could have
> registered.
> 
> I see no reason for this hook to change the LSM state, only to answer
> the question: allowed/disallowed (eventually return an error cause it
> is unable to give an answer which falls into the disallow category).

How about renaming it "security_userns_may_setns()" for clarity?

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Lukasz Pawelczyk]

On pią, 2015-07-31 at 22:48 -0500, Serge E. Hallyn wrote:
> On Fri, Jul 31, 2015 at 11:28:56AM +0200, Lukasz Pawelczyk wrote:
> > On czw, 2015-07-30 at 16:30 -0500, Serge E. Hallyn wrote:
> > > On Fri, Jul 24, 2015 at 12:04:35PM +0200, Lukasz Pawelczyk wrote:
> > > > @@ -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;
> > > 
> > > So at this point the LSM thinks current is in the new ns.  If
> > > prepare_creds() fails below, should it be informed of that?
> > > (Or am I over-thinking this?)
> > > 
> > > > +
> > > >  	cred = prepare_creds();
> > > >  	if (!cred)
> > > >  		return -ENOMEM;
> > 
> > Hmm, the use case for this hook I had in mind was just to allow or
> > disallow the operation based on the information passed in 
> > arguments.
> > Not to register the current in any way so LSM can think it is or 
> > isn't
> > in the new namespace.
> > 
> > I think that any other LSM check that would like to know in what
> > namespace the current is, would just check that from current's 
> > creds.
> > Not use some stale and duplicated information the above hook could 
> > have
> > registered.
> > 
> > I see no reason for this hook to change the LSM state, only to 
> > answer
> > the question: allowed/disallowed (eventually return an error cause 
> > it
> > is unable to give an answer which falls into the disallow 
> > category).
> 
> How about renaming it "security_userns_may_setns()" for clarity?

I personally have nothing against it. However looking at already
existing hooks only one of them has "may" in the name (unix_may_send)
while a lot clearly have exactly this purpose (e.g. most of inode_*
family, some from file_* and task_*). So it seems the trend is against
it.

What do you think? Anyone else has an opinion?



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

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Kees Cook]

On Mon, Aug 3, 2015 at 4:34 AM, Lukasz Pawelczyk
<l.pawelczyk@samsung.com> wrote:
> On pią, 2015-07-31 at 22:48 -0500, Serge E. Hallyn wrote:
>> On Fri, Jul 31, 2015 at 11:28:56AM +0200, Lukasz Pawelczyk wrote:
>> > On czw, 2015-07-30 at 16:30 -0500, Serge E. Hallyn wrote:
>> > > On Fri, Jul 24, 2015 at 12:04:35PM +0200, Lukasz Pawelczyk wrote:
>> > > > @@ -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;
>> > >
>> > > So at this point the LSM thinks current is in the new ns.  If
>> > > prepare_creds() fails below, should it be informed of that?
>> > > (Or am I over-thinking this?)
>> > >
>> > > > +
>> > > >         cred = prepare_creds();
>> > > >         if (!cred)
>> > > >                 return -ENOMEM;
>> >
>> > Hmm, the use case for this hook I had in mind was just to allow or
>> > disallow the operation based on the information passed in
>> > arguments.
>> > Not to register the current in any way so LSM can think it is or
>> > isn't
>> > in the new namespace.
>> >
>> > I think that any other LSM check that would like to know in what
>> > namespace the current is, would just check that from current's
>> > creds.
>> > Not use some stale and duplicated information the above hook could
>> > have
>> > registered.
>> >
>> > I see no reason for this hook to change the LSM state, only to
>> > answer
>> > the question: allowed/disallowed (eventually return an error cause
>> > it
>> > is unable to give an answer which falls into the disallow
>> > category).
>>
>> How about renaming it "security_userns_may_setns()" for clarity?
>
> I personally have nothing against it. However looking at already
> existing hooks only one of them has "may" in the name (unix_may_send)
> while a lot clearly have exactly this purpose (e.g. most of inode_*
> family, some from file_* and task_*). So it seems the trend is against
> it.
>
> What do you think? Anyone else has an opinion?

Personally, I prefer that hooks be named as closely to their caller,
or calling context, as possible. In this case, it seems like "may" is
implied. It's an LSM like all the others, so it can fail, which would
cause the caller to fail too, so "may" tends to be implicit. I would
leave it as-is, but I could be convinced otherwise.

-Kees

-- 
Kees Cook
Chrome OS Security

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Paul Moore]

On Mon, Aug 3, 2015 at 9:38 PM, Kees Cook <keescook@chromium.org> wrote:
> On Mon, Aug 3, 2015 at 4:34 AM, Lukasz Pawelczyk
> <l.pawelczyk@samsung.com> wrote:
>> On pią, 2015-07-31 at 22:48 -0500, Serge E. Hallyn wrote:
>>> On Fri, Jul 31, 2015 at 11:28:56AM +0200, Lukasz Pawelczyk wrote:
>>> > On czw, 2015-07-30 at 16:30 -0500, Serge E. Hallyn wrote:
>>> > > On Fri, Jul 24, 2015 at 12:04:35PM +0200, Lukasz Pawelczyk wrote:
>>> > > > @@ -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;
>>> > >
>>> > > So at this point the LSM thinks current is in the new ns.  If
>>> > > prepare_creds() fails below, should it be informed of that?
>>> > > (Or am I over-thinking this?)
>>> > >
>>> > > > +
>>> > > >         cred = prepare_creds();
>>> > > >         if (!cred)
>>> > > >                 return -ENOMEM;
>>> >
>>> > Hmm, the use case for this hook I had in mind was just to allow or
>>> > disallow the operation based on the information passed in
>>> > arguments.
>>> > Not to register the current in any way so LSM can think it is or
>>> > isn't
>>> > in the new namespace.
>>> >
>>> > I think that any other LSM check that would like to know in what
>>> > namespace the current is, would just check that from current's
>>> > creds.
>>> > Not use some stale and duplicated information the above hook could
>>> > have
>>> > registered.
>>> >
>>> > I see no reason for this hook to change the LSM state, only to
>>> > answer
>>> > the question: allowed/disallowed (eventually return an error cause
>>> > it
>>> > is unable to give an answer which falls into the disallow
>>> > category).
>>>
>>> How about renaming it "security_userns_may_setns()" for clarity?
>>
>> I personally have nothing against it. However looking at already
>> existing hooks only one of them has "may" in the name (unix_may_send)
>> while a lot clearly have exactly this purpose (e.g. most of inode_*
>> family, some from file_* and task_*). So it seems the trend is against
>> it.
>>
>> What do you think? Anyone else has an opinion?
>
> Personally, I prefer that hooks be named as closely to their caller,
> or calling context, as possible. In this case, it seems like "may" is
> implied. It's an LSM like all the others, so it can fail, which would
> cause the caller to fail too, so "may" tends to be implicit. I would
> leave it as-is, but I could be convinced otherwise.

I agree with Kees, sticking as close as possible to the general format
of "security_<caller>" for LSM hooks makes it easier when
reading/reviewing code.

-- 
paul moore
www.paul-moore.com

Re: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations

[Paul Moore]

On Fri, Jul 24, 2015 at 6:04 AM, Lukasz Pawelczyk
<l.pawelczyk@samsung.com> wrote:
> 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@samsung.com>
> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
> ---
>  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(+)

I'm not sure at this point in time we know what we want to do with
SELinux and these hooks, if anything, but they look reasonable to me.

Acked-by: Paul Moore <paul@paul-moore.com>

> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 9429f05..228558c 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1261,6 +1261,23 @@
>   *     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 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
> @@ -1613,6 +1630,12 @@ union security_list_options {
>                                 struct audit_context *actx);
>         void (*audit_rule_free)(void *lsmrule);
>  #endif /* CONFIG_AUDIT */
> +
> +#ifdef CONFIG_USER_NS
> +       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_USER_NS */
>  };
>
>  struct security_hook_heads {
> @@ -1824,6 +1847,11 @@ struct security_hook_heads {
>         struct list_head audit_rule_match;
>         struct list_head audit_rule_free;
>  #endif /* CONFIG_AUDIT */
> +#ifdef CONFIG_USER_NS
> +       struct list_head userns_create;
> +       struct list_head userns_free;
> +       struct list_head userns_setns;
> +#endif /* CONFIG_USER_NS */
>  };
>
>  /*
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 79d85dd..1b0eccc 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -1584,6 +1584,29 @@ static inline void security_audit_rule_free(void *lsmrule)
>  #endif /* CONFIG_SECURITY */
>  #endif /* CONFIG_AUDIT */
>
> +#ifdef CONFIG_USER_NS
> +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_USER_NS */
> +
>  #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 595fffa..5e66388 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
> @@ -1542,6 +1543,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule,
>  }
>  #endif /* CONFIG_AUDIT */
>
> +#ifdef CONFIG_USER_NS
> +
> +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_USER_NS */
> +
>  struct security_hook_heads security_hook_heads = {
>         .binder_set_context_mgr =
>                 LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr),
> @@ -1886,4 +1906,12 @@ struct security_hook_heads security_hook_heads = {
>         .audit_rule_free =
>                 LIST_HEAD_INIT(security_hook_heads.audit_rule_free),
>  #endif /* CONFIG_AUDIT */
> +#ifdef CONFIG_USER_NS
> +       .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_USER_NS */
>  };
> --
> 2.4.3
>



-- 
paul moore
www.paul-moore.com