From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39326) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bSyH3-0005PN-VQ for qemu-devel@nongnu.org; Thu, 28 Jul 2016 23:15:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bSyH1-0002mp-Np for qemu-devel@nongnu.org; Thu, 28 Jul 2016 23:15:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22251) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bSyH1-0002ml-Hk for qemu-devel@nongnu.org; Thu, 28 Jul 2016 23:15:43 -0400 Date: Fri, 29 Jul 2016 06:15:36 +0300 From: "Michael S. Tsirkin" Message-ID: <1469762011-7902-11-git-send-email-mst@redhat.com> References: <1469762011-7902-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1469762011-7902-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PULL 10/41] virtio: check vring descriptor buffer length List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Prasad J Pandit , Li Qiang , Stefan Hajnoczi From: Prasad J Pandit virtio back end uses set of buffers to facilitate I/O operations. An infinite loop unfolds in virtqueue_pop() if a buffer was of zero size. Add check to avoid it. Reported-by: Li Qiang Signed-off-by: Prasad J Pandit Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Stefan Hajnoczi --- hw/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 752b271..b4d0511 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -458,6 +458,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, hwaddr *addr, struct iove unsigned num_sg = *p_num_sg; assert(num_sg <= max_num_sg); + if (!sz) { + error_report("virtio: zero sized buffers are not allowed"); + exit(1); + } + while (sz) { hwaddr len = sz; -- MST