selinux: Only audit permissions specified in policy

Only audit the permissions specified by the policy rules.

Before:
type=AVC msg=audit(01/28/2010 14:30:46.690:3250) : avc:  denied  { read
append } for  pid=14092 comm=foo name=test_file dev=dm-1 ino=132932
scontext=unconfined_u:unconfined_r:load_policy_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:rpm_tmp_t:s0 tclass=file

After:
type=AVC msg=audit(01/28/2010 14:52:37.448:26) : avc:  denied
{ append } for  pid=1917 comm=foo name=test_file dev=dm-1 ino=132932
scontext=unconfined_u:unconfined_r:load_policy_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:rpm_tmp_t:s0 tclass=file

Reference:
https://bugzilla.redhat.com/show_bug.cgi?id=558499

Reported-by: Tom London <selinux@gmail.com>
Signed-off-by: Stephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index 3ee9b6a..db0fd9f 100644 (file)
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -489,17 +489,14 @@ void avc_audit(u32 ssid, u32 tsid,
        struct common_audit_data stack_data;
        u32 denied, audited;
        denied = requested & ~avd->allowed;
-       if (denied) {
-               audited = denied;
-               if (!(audited & avd->auditdeny))
-                       return;
-       } else if (result) {
+       if (denied)
+               audited = denied & avd->auditdeny;
+       else if (result)
                audited = denied = requested;
-       } else {
-               audited = requested;
-               if (!(audited & avd->auditallow))
-                       return;
-       }
+       else
+               audited = requested & avd->auditallow;
+       if (!audited)
+               return;
        if (!a) {
                a = &stack_data;
                memset(a, 0, sizeof(*a));