libceph: handle an empty authorize reply

idryomov · idryomov · commit 0fd3fd0a9bb0 · 2019-02-18T18:05:33.000+01:00
The authorize reply can be empty, for example when the ticket used to build the authorizer is too old and TAG_BADAUTHORIZER is returned from the service. Calling ->verify_authorizer_reply() results in an attempt to decrypt and validate (somewhat) random data in au->buf (most likely the signature block from calc_signature()), which fails and ends up in con_fault_finish() with !con->auth_retry. The ticket isn't invalidated and the connection is retried again and again until a new ticket is obtained from the monitor: libceph: osd2 192.168.122.1:6809 bad authorize reply libceph: osd2 192.168.122.1:6809 bad authorize reply libceph: osd2 192.168.122.1:6809 bad authorize reply libceph: osd2 192.168.122.1:6809 bad authorize reply Let TAG_BADAUTHORIZER handler kick in and increment con->auth_retry. Cc: stable@vger.kernel.org Fixes: 5c056fd ("libceph: verify authorize reply on connect") Link: https://tracker.ceph.com/issues/20164 Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Sage Weil <sage@redhat.com>
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
@@ -2058,6 +2058,8 @@ static int process_connect(struct ceph_connection *con)
 	dout("process_connect on %p tag %d\n", con, (int)con->in_tag);
 
 	if (con->auth) {
+		int len = le32_to_cpu(con->in_reply.authorizer_len);
+
 		/*
 		 * Any connection that defines ->get_authorizer()
 		 * should also define ->add_authorizer_challenge() and
@@ -2067,8 +2069,7 @@ static int process_connect(struct ceph_connection *con)
 		 */
 		if (con->in_reply.tag == CEPH_MSGR_TAG_CHALLENGE_AUTHORIZER) {
 			ret = con->ops->add_authorizer_challenge(
-				    con, con->auth->authorizer_reply_buf,
-				    le32_to_cpu(con->in_reply.authorizer_len));
+				    con, con->auth->authorizer_reply_buf, len);
 			if (ret < 0)
 				return ret;
 
@@ -2078,10 +2079,12 @@ static int process_connect(struct ceph_connection *con)
 			return 0;
 		}
 
-		ret = con->ops->verify_authorizer_reply(con);
-		if (ret < 0) {
-			con->error_msg = "bad authorize reply";
-			return ret;
+		if (len) {
+			ret = con->ops->verify_authorizer_reply(con);
+			if (ret < 0) {
+				con->error_msg = "bad authorize reply";
+				return ret;
+			}
 		}
 	}
 
