From patchwork Wed Jul 27 15:37:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 9250019 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5249E607D8 for ; Wed, 27 Jul 2016 15:38:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3B077201F5 for ; Wed, 27 Jul 2016 15:38:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2F76D26B39; Wed, 27 Jul 2016 15:38:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7F5782522B for ; Wed, 27 Jul 2016 15:38:44 +0000 (UTC) Received: from localhost ([::1]:47155 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bSQux-0006LF-Os for patchwork-qemu-devel@patchwork.kernel.org; Wed, 27 Jul 2016 11:38:43 -0400 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 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 61C545D4; Wed, 27 Jul 2016 15:38:05 +0000 (UTC) Received: from javelin.localdomain (vpn1-5-105.ams2.redhat.com [10.36.5.105]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u6RFbwRC032060 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 27 Jul 2016 11:38:01 -0400 From: P J P To: Qemu Developers Date: Wed, 27 Jul 2016 21:07:56 +0530 Message-Id: <1469633876-23209-1-git-send-email-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 27 Jul 2016 15:38:05 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] virtio: check vring descriptor buffer length X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Li Qiang , Prasad J Pandit , Stefan Hajnoczi , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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: 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 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;