From patchwork Fri Sep 23 19:57:20 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 9348759 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 649F1607F2 for ; Fri, 23 Sep 2016 20:06:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 578782ADC5 for ; Fri, 23 Sep 2016 20:06:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 49DD92ADBD; Fri, 23 Sep 2016 20:06:57 +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 BF1822ADBD for ; Fri, 23 Sep 2016 20:06:56 +0000 (UTC) Received: from localhost ([::1]:50773 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bnWkJ-0002wc-Bp for patchwork-qemu-devel@patchwork.kernel.org; Fri, 23 Sep 2016 16:06:55 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54219) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bnWb5-0001Vs-61 for qemu-devel@nongnu.org; Fri, 23 Sep 2016 15:57:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bnWb4-0001y7-26 for qemu-devel@nongnu.org; Fri, 23 Sep 2016 15:57:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23604) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bnWb3-0001xn-Si for qemu-devel@nongnu.org; Fri, 23 Sep 2016 15:57:22 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (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 4FEB532B58A; Fri, 23 Sep 2016 19:57:21 +0000 (UTC) Received: from redhat.com (vpn-55-222.rdu2.redhat.com [10.10.55.222]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id u8NJvKol030802; Fri, 23 Sep 2016 15:57:20 -0400 Date: Fri, 23 Sep 2016 22:57:20 +0300 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <1474658051-18617-5-git-send-email-mst@redhat.com> References: <1474658051-18617-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1474658051-18617-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Fri, 23 Sep 2016 19:57:21 +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] [PULL 04/19] virtio: add check for descriptor's mapped address 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: Qinghao Tang , Peter Maydell , Laszlo Ersek , Prasad J Pandit 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. If its size is too large, 'cpu_physical_memory_map' could return a null address. This would result in a null dereference while un-mapping descriptors. Add check to avoid it. Reported-by: Qinghao Tang Signed-off-by: Prasad J Pandit Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin Reviewed-by: Laszlo Ersek --- hw/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index fcf3358..bb656b1 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -495,6 +495,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, hwaddr *addr, struct iove } iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write); + if (!iov[num_sg].iov_base) { + error_report("virtio: bogus descriptor or out of resources"); + exit(1); + } + iov[num_sg].iov_len = len; addr[num_sg] = pa;