ceph: ensure auth ops are defined before use

In the create_authorizer method for both the mds and osd clients,
the auth_client->ops pointer is blindly dereferenced. There is no
obvious guarantee that this pointer has been assigned. And
furthermore, even if the ops pointer is non-null there is definitely
no guarantee that the create_authorizer or destroy_authorizer
methods are defined.

Add checks in both routines to make sure they are defined (non-null)
before use. Add similar checks in a few other spots in these files
while we're at it.

Signed-off-by: Alex Elder <[e-mail]>
Reviewed-by: Sage Weil <[e-mail]>

fs/ceph/mds_client.c

···
 	int ret = 0;
 
 	if (force_new && auth->authorizer) {
-		ac->ops->destroy_authorizer(ac, auth->authorizer);
+		if (ac->ops && ac->ops->destroy_authorizer)
+			ac->ops->destroy_authorizer(ac, auth->authorizer);
 		auth->authorizer = NULL;
 	}
-	if (auth->authorizer == NULL) {
-		if (ac->ops->create_authorizer) {
-			ret = ac->ops->create_authorizer(ac,
-						CEPH_ENTITY_TYPE_MDS, auth);
-			if (ret)
-				return ret;
-		}
+	if (!auth->authorizer && ac->ops && ac->ops->create_authorizer) {
+		ret = ac->ops->create_authorizer(ac, CEPH_ENTITY_TYPE_MDS, auth);
+		if (ret)
+			return ret;
 	}
 
 	*proto = ac->protocol;

net/ceph/osd_client.c

···
 {
 	dout("put_osd %p %d -> %d\n", osd, atomic_read(&osd->o_ref),
 	     atomic_read(&osd->o_ref) - 1);
-	if (atomic_dec_and_test(&osd->o_ref)) {
+	if (atomic_dec_and_test(&osd->o_ref) && osd->o_auth.authorizer) {
 		struct ceph_auth_client *ac = osd->o_osdc->client->monc.auth;
 
-		if (osd->o_auth.authorizer)
+		if (ac->ops && ac->ops->destroy_authorizer)
 			ac->ops->destroy_authorizer(ac, osd->o_auth.authorizer);
 		kfree(osd);
 	}
···
 	int ret = 0;
 
 	if (force_new && auth->authorizer) {
-		ac->ops->destroy_authorizer(ac, auth->authorizer);
+		if (ac->ops && ac->ops->destroy_authorizer)
+			ac->ops->destroy_authorizer(ac, auth->authorizer);
 		auth->authorizer = NULL;
 	}
-	if (auth->authorizer == NULL) {
+	if (!auth->authorizer && ac->ops && ac->ops->create_authorizer) {
 		ret = ac->ops->create_authorizer(ac, CEPH_ENTITY_TYPE_OSD, auth);
 		if (ret)
 			return ret;
···
 	struct ceph_osd_client *osdc = o->o_osdc;
 	struct ceph_auth_client *ac = osdc->client->monc.auth;
 
+	/*
+	 * XXX If ac->ops or ac->ops->verify_authorizer_reply is null,
+	 * XXX which do we do:  succeed or fail?
+	 */
 	return ac->ops->verify_authorizer_reply(ac, o->o_auth.authorizer, len);
 }
 
···
 	struct ceph_osd_client *osdc = o->o_osdc;
 	struct ceph_auth_client *ac = osdc->client->monc.auth;
 
-	if (ac->ops->invalidate_authorizer)
+	if (ac->ops && ac->ops->invalidate_authorizer)
 		ac->ops->invalidate_authorizer(ac, CEPH_ENTITY_TYPE_OSD);
 
 	return ceph_monc_validate_auth(&osdc->client->monc);