[PATCH 02/10] Security: Add Hook to test if the particular xattr is part of a MAC model.

David P. Quigley
2010-06-08T17:44:22Z

There are areas in the Labeled NFS code where where we need to test if the
attribute being requested exhibits the semantics of a MAC model. This allows us
to make sure that we get the desired semantics from the attribute instead of
something else such as capabilities or a time based LSM.

Signed-off-by: Matthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: David P. Quigley <dpquigl@tycho.nsa.gov>
---
include/linux/security.h | 11 +++++++++++
security/capability.c | 6 ++++++
security/security.c | 6 ++++++
security/selinux/hooks.c | 6 ++++++
security/smack/smack_lsm.c | 11 +++++++++++
5 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 4d01784..9597620 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1373,6 +1373,10 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
* @pages contains the number of pages.
* Return 0 if permission is granted.
*
+ * @ismaclabel:
+ * Check if the extended attribute specified by @name represents a MAC label.
+ * @name full extended attribute name to check against LSM as a MAC label.
+ *
* @secid_to_secctx:
* Convert secid to security context.
* @secid contains the security ID.
@@ -1664,6 +1668,7 @@ struct security_operations {

int (*getprocattr) (struct task_struct *p, char *name, char **value);
int (*setprocattr) (struct task_struct *p, 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);
void (*release_secctx) (char *secdata, u32 seclen);
@@ -1919,6 +1924,7 @@ 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);
int security_netlink_recv(struct sk_buff *skb, int cap);
+int security_ismaclabel(const char *name);
int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen);
int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
void security_release_secctx(char *secdata, u32 seclen);
@@ -2676,6 +2682,11 @@ static inline int security_netlink_recv(struct sk_buff *skb, int cap)
return cap_netlink_recv(skb, cap);
}

+static inline int security_ismaclabel(const char *name)
+{
+ return 0;
+}
+
static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return -EOPNOTSUPP;
diff --git a/security/capability.c b/security/capability.c
index 9ce1c2f..0d8f7e9 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -829,6 +829,11 @@ static int cap_setprocattr(struct task_struct *p, char *name, void *value,
return -EINVAL;
}

+static int cap_ismaclabel(const char *name)
+{
+ return 0;
+}
+
static int cap_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return -EOPNOTSUPP;
@@ -1064,6 +1069,7 @@ void security_fixup_ops(struct security_operations *ops)
set_to_cap_if_null(ops, d_instantiate);
set_to_cap_if_null(ops, getprocattr);
set_to_cap_if_null(ops, setprocattr);
+ set_to_cap_if_null(ops, ismaclabel);
set_to_cap_if_null(ops, secid_to_secctx);
set_to_cap_if_null(ops, secctx_to_secid);
set_to_cap_if_null(ops, release_secctx);
diff --git a/security/security.c b/security/security.c
index c1b6847..1f0765c 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1013,6 +1013,12 @@ int security_netlink_recv(struct sk_buff *skb, int cap)
}
EXPORT_SYMBOL(security_netlink_recv);

+int security_ismaclabel(const char *name)
+{
+ return security_ops->ismaclabel(name);
+}
+EXPORT_SYMBOL(security_ismaclabel);
+
int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return security_ops->secid_to_secctx(secid, secdata, seclen);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 435c51f..8239f5c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5372,6 +5372,11 @@ abort_change:
return error;
}

+static int selinux_ismaclabel(const char *name)
+{
+ return (strcmp(name,XATTR_NAME_SELINUX) == 0);
+}
+
static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)
{
return security_sid_to_context(secid, secdata, seclen);
@@ -5610,6 +5615,7 @@ static struct security_operations selinux_ops = {
.getprocattr = selinux_getprocattr,
.setprocattr = selinux_setprocattr,

+ .ismaclabel = selinux_ismaclabel,
.secid_to_secctx = selinux_secid_to_secctx,
.secctx_to_secid = selinux_secctx_to_secid,
.release_secctx = selinux_release_secctx,
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index fdfeaa2..449e223 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3012,6 +3012,16 @@ static void smack_audit_rule_free(void *vrule)
#endif /* CONFIG_AUDIT */

/**
+ * smack_ismaclabel - check if xattr @name references a smack MAC label
+ * @name: Full xattr name to check.
+ */
+static int smack_ismaclabel(const char *name)
+{
+ return (strcmp(name, XATTR_NAME_SMACK) == 0);
+}
+
+
+/**
* smack_secid_to_secctx - return the smack label for a secid
* @secid: incoming integer
* @secdata: destination
@@ -3199,6 +3209,7 @@ struct security_operations smack_ops = {
.audit_rule_free = smack_audit_rule_free,
#endif /* CONFIG_AUDIT */

+ .ismaclabel = smack_ismaclabel,
.secid_to_secctx = smack_secid_to_secctx,
.secctx_to_secid = smack_secctx_to_secid,
.release_secctx = smack_release_secctx,
--
1.6.2.5