RDMA/rtrs-srv: Avoid null pointer deref during path establishment

For RTRS path establishment, RTRS client initiates and completes con_num
of connections. After establishing all its connections, the information
is exchanged between the client and server through the info_req message.
During this exchange, it is essential that all connections have been
established, and the state of the RTRS srv path is CONNECTED.

So add these sanity checks, to make sure we detect and abort process in
error scenarios to avoid null pointer deref.
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Grzegorz Prajsner <grzegorz.prajsner@ionos.com>
Link: https://patch.msgid.link/20240821112217.41827-9-haris.iqbal@ionos.comSigned-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/ulp/rtrs/rtrs-srv.c

@@ -935,12 +935,11 @@ static void rtrs_srv_info_req_done(struct ib_cq *cq, struct ib_wc *wc)
 	if (err)
 		goto close;
 
-out:
 	rtrs_iu_free(iu, srv_path->s.dev->ib_dev, 1);
 	return;
 close:
+	rtrs_iu_free(iu, srv_path->s.dev->ib_dev, 1);
 	close_path(srv_path);
-	goto out;
 }
 
 static int post_recv_info_req(struct rtrs_srv_con *con)
@@ -991,6 +990,16 @@ static int post_recv_path(struct rtrs_srv_path *srv_path)
 			q_size = SERVICE_CON_QUEUE_DEPTH;
 		else
 			q_size = srv->queue_depth;
+		if (srv_path->state != RTRS_SRV_CONNECTING) {
+			rtrs_err(s, "Path state invalid. state %s\n",
+				 rtrs_srv_state_str(srv_path->state));
+			return -EIO;
+		}
+
+		if (!srv_path->s.con[cid]) {
+			rtrs_err(s, "Conn not set for %d\n", cid);
+			return -EIO;
+		}
 
 		err = post_recv_io(to_srv_con(srv_path->s.con[cid]), q_size);
 		if (err) {