Smack: onlycap limits on CAP_MAC_ADMIN

Smack is integrated with the POSIX capabilities scheme,
using the capabilities CAP_MAC_OVERRIDE and CAP_MAC_ADMIN to
determine if a process is allowed to ignore Smack checks or
change Smack related data respectively. Smack provides an
additional restriction that if an onlycap value is set
by writing to /smack/onlycap only tasks with that Smack
label are allowed to use CAP_MAC_OVERRIDE.

This change adds CAP_MAC_ADMIN as a capability that is affected
by the onlycap mechanism.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 76feb31eb823..99b36124f712 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -283,6 +283,19 @@ static inline char *smk_of_current(void)
 }
 
 /*
+ * Is the task privileged and allowed to be privileged
+ * by the onlycap rule.
+ */
+static inline int smack_privileged(int cap)
+{
+        if (!capable(cap))
+                return 0;
+        if (smack_onlycap == NULL || smack_onlycap == smk_of_current())
+                return 1;
+        return 0;
+}
+
+/*
  * logging functions
  */
 #define SMACK_AUDIT_DENIED 0x1