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 <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 6 insertions, 8 deletions

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index b71ffd2c8094..462281742aef 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3406,16 +3406,14 @@ static int get_authorizer(struct ceph_connection *con,
 	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;