selinux: Report permissive mode in avc: denied messages.

We cannot presently tell from an avc: denied message whether access was in
fact denied or was allowed due to global or per-domain permissive mode.
Add a permissive= field to the avc message to reflect this information.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Paul Moore <pmoore@redhat.com>

security/selinux/avc.c

@@ -444,11 +444,15 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
 	avc_dump_query(ab, ad->selinux_audit_data->ssid,
 			   ad->selinux_audit_data->tsid,
 			   ad->selinux_audit_data->tclass);
+	if (ad->selinux_audit_data->denied) {
+		audit_log_format(ab, " permissive=%u",
+				 ad->selinux_audit_data->result ? 0 : 1);
+	}
 }
 
 /* This is the slow part of avc audit with big stack footprint */
 noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
-		u32 requested, u32 audited, u32 denied,
+		u32 requested, u32 audited, u32 denied, int result,
 		struct common_audit_data *a,
 		unsigned flags)
 {
@@ -477,6 +481,7 @@ noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 	sad.tsid = tsid;
 	sad.audited = audited;
 	sad.denied = denied;
+	sad.result = result;
 
 	a->selinux_audit_data = &sad;
 

security/selinux/hooks.c

@@ -2770,6 +2770,7 @@ static int selinux_inode_follow_link(struct dentry *dentry, struct nameidata *na
 
 static noinline int audit_inode_permission(struct inode *inode,
 					   u32 perms, u32 audited, u32 denied,
+					   int result,
 					   unsigned flags)
 {
 	struct common_audit_data ad;
@@ -2780,7 +2781,7 @@ static noinline int audit_inode_permission(struct inode *inode,
 	ad.u.inode = inode;
 
 	rc = slow_avc_audit(current_sid(), isec->sid, isec->sclass, perms,
-			    audited, denied, &ad, flags);
+			    audited, denied, result, &ad, flags);
 	if (rc)
 		return rc;
 	return 0;
@@ -2822,7 +2823,7 @@ static int selinux_inode_permission(struct inode *inode, int mask)
 	if (likely(!audited))
 		return rc;
 
-	rc2 = audit_inode_permission(inode, perms, audited, denied, flags);
+	rc2 = audit_inode_permission(inode, perms, audited, denied, rc, flags);
 	if (rc2)
 		return rc2;
 	return rc;

security/selinux/include/avc.h

@@ -102,7 +102,7 @@ static inline u32 avc_audit_required(u32 requested,
 }
 
 int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
-		   u32 requested, u32 audited, u32 denied,
+		   u32 requested, u32 audited, u32 denied, int result,
 		   struct common_audit_data *a,
 		   unsigned flags);
 
@@ -137,7 +137,7 @@ static inline int avc_audit(u32 ssid, u32 tsid,
 	if (likely(!audited))
 		return 0;
 	return slow_avc_audit(ssid, tsid, tclass,
-			      requested, audited, denied,
+			      requested, audited, denied, result,
 			      a, 0);
 }