Return-Path: Received: from mail.kernel.org ([198.145.29.99]:38414 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933206AbeFIPgQ (ORCPT ); Sat, 9 Jun 2018 11:36:16 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Wang , "David S. Miller" Subject: [PATCH 4.14 36/41] virtio-net: correctly check num_buf during err path Date: Sat, 9 Jun 2018 17:30:08 +0200 Message-Id: <20180609152928.397880125@linuxfoundation.org> In-Reply-To: <20180609152926.389750182@linuxfoundation.org> References: <20180609152926.389750182@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang [ Upstream commit 850e088d5bbb333342fd4def08d0a4035f2b7126 ] If we successfully linearize the packet, num_buf will be set to zero which may confuse error handling path which assumes num_buf is at least 1 and this can lead the code tries to pop the descriptor of next buffer. Fixing this by checking num_buf against 1 before decreasing. Fixes: 4941d472bf95 ("virtio-net: do not reset during XDP set") Signed-off-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -777,7 +777,7 @@ err_xdp: rcu_read_unlock(); err_skb: put_page(page); - while (--num_buf) { + while (num_buf-- > 1) { buf = virtqueue_get_buf(rq->vq, &len); if (unlikely(!buf)) { pr_debug("%s: rx error: %d buffers missing\n",