From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40681) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bSQuQ-0005zI-QQ for qemu-devel@nongnu.org; Wed, 27 Jul 2016 11:38:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bSQuM-0007Ni-K4 for qemu-devel@nongnu.org; Wed, 27 Jul 2016 11:38:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53432) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bSQuM-0007Mp-ES for qemu-devel@nongnu.org; Wed, 27 Jul 2016 11:38:06 -0400 From: P J P Date: Wed, 27 Jul 2016 21:07:56 +0530 Message-Id: <1469633876-23209-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] virtio: check vring descriptor buffer length List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: "Michael S. Tsirkin" , Li Qiang , Stefan Hajnoczi , Prasad J Pandit 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 --- hw/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 30ede3d..8de896c 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -457,6 +457,11 @@ 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; -- 2.5.5