From patchwork Mon Sep 19 18:25:45 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Prasad Pandit X-Patchwork-Id: 9340315 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 D6E3A607D0 for ; Mon, 19 Sep 2016 18:32:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CDBEF29619 for ; Mon, 19 Sep 2016 18:32:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C2B562961C; Mon, 19 Sep 2016 18:32:08 +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 4A1C029619 for ; Mon, 19 Sep 2016 18:32:08 +0000 (UTC) Received: from localhost ([::1]:57550 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm3MN-000145-Do for patchwork-qemu-devel@patchwork.kernel.org; Mon, 19 Sep 2016 14:32:07 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42742) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm3GU-0005RC-FJ for qemu-devel@nongnu.org; Mon, 19 Sep 2016 14:26:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bm3GP-00051p-40 for qemu-devel@nongnu.org; Mon, 19 Sep 2016 14:26:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38094) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bm3GO-00051f-Tu for qemu-devel@nongnu.org; Mon, 19 Sep 2016 14:25:57 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (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 572C580096; Mon, 19 Sep 2016 18:25:56 +0000 (UTC) Received: from javelin.localdomain (vpn1-51-140.bne.redhat.com [10.64.51.140]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u8JIPlpV011859 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 19 Sep 2016 14:25:51 -0400 From: P J P To: Qemu Developers Date: Mon, 19 Sep 2016 23:55:45 +0530 Message-Id: <1474309545-13253-1-git-send-email-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 19 Sep 2016 18:25:56 +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 v3] 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 , Laszlo Ersek , 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. 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: Laszlo Ersek Reviewed-by: Stefan Hajnoczi --- hw/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) Update per: -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg04329.html diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 15ee3a7..a4ebf8c 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -472,6 +472,11 @@ 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;