selinux: replace BUG_ONs with WARN_ONs in avc.c

These checks are only guarding against programming errors that could
silently grant too many permissions. These cases are better handled with
WARN_ON(), since it doesn't really help much to crash the machine in
this case.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>

security/selinux/avc.c

@@ -1059,7 +1059,8 @@ int avc_has_extended_perms(struct selinux_state *state,
 	int rc = 0, rc2;
 
 	xp_node = &local_xp_node;
-	BUG_ON(!requested);
+	if (WARN_ON(!requested))
+		return -EACCES;
 
 	rcu_read_lock();
 
@@ -1149,7 +1150,8 @@ inline int avc_has_perm_noaudit(struct selinux_state *state,
 	int rc = 0;
 	u32 denied;
 
-	BUG_ON(!requested);
+	if (WARN_ON(!requested))
+		return -EACCES;
 
 	rcu_read_lock();