vhost: fix queue number check when setting inflight FD

In function vhost_user_set_inflight_fd, queue number in inflight
message is used to access virtqueue. However, queue number could
be larger than VHOST_MAX_VRING and cause write OOB as this number
will be used to write inflight info in virtqueue structure. This
patch checks the queue number to avoid the issue and also make
sure virtqueues are allocated before setting inflight information.

Fixes: ad0a4ae ("vhost: checkout resubmit inflight information")
Cc: stable@dpdk.org

Reported-by: Wenxiang Qian <leonwxqian@gmail.com>
Signed-off-by: Chenbo Xia <chenbo.xia@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

lib/vhost/vhost_user.c

@@ -2883,6 +2883,9 @@ vhost_user_check_and_alloc_queue_pair(struct virtio_net *dev,
 	case VHOST_USER_SET_VRING_ADDR:
 		vring_idx = ctx->msg.payload.addr.index;
 		break;
+	case VHOST_USER_SET_INFLIGHT_FD:
+		vring_idx = ctx->msg.payload.inflight.num_queues - 1;
+		break;
 	default:
 		return 0;
 	}