From patchwork Thu Apr 3 16:52:17 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 336678 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id B48DF140082 for ; Fri, 4 Apr 2014 03:57:37 +1100 (EST) Received: from localhost ([::1]:45125 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WVkxL-0007AQ-Oz for incoming@patchwork.ozlabs.org; Thu, 03 Apr 2014 12:57:35 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47690) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WVkro-0006cB-MQ for qemu-devel@nongnu.org; Thu, 03 Apr 2014 12:51:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WVkrj-0005pQ-NK for qemu-devel@nongnu.org; Thu, 03 Apr 2014 12:51:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20980) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WVkrh-0005nh-DZ; Thu, 03 Apr 2014 12:51:47 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s33GpfN3010153 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 3 Apr 2014 12:51:41 -0400 Received: from redhat.com (vpn1-4-68.ams2.redhat.com [10.36.4.68]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s33GpcWd020373; Thu, 3 Apr 2014 12:51:38 -0400 Date: Thu, 3 Apr 2014 19:52:17 +0300 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <1396543778-22307-22-git-send-email-mst@redhat.com> References: <1396543778-22307-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1396543778-22307-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-MIME-Autoconverted: from 8bit to quoted-printable by mx1.redhat.com id s33GpfN3010153 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Peter Maydell , mdroth@linux.vnet.ibm.com, qemu-stable@nongnu.org, dgilbert@redhat.com, Anthony Liguori , Paolo Bonzini , =?us-ascii?B?PT9VVEYtOD9xP0FuZHJlYXM9MjBGPUMzPUE0cmJlcj89?= Subject: [Qemu-devel] [PATCH v5 21/24] virtio-scsi: fix buffer overrun on invalid state load X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org CVE-2013-4542 hw/scsi/scsi-bus.c invokes load_request. virtio_scsi_load_request does: qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem)); this probably can make elem invalid, for example, make in_num or out_num huge, then: virtio_scsi_parse_req(s, vs->cmd_vqs[n], req); will do: if (req->elem.out_num > 1) { qemu_sgl_init_external(req, &req->elem.out_sg[1], &req->elem.out_addr[1], req->elem.out_num - 1); } else { qemu_sgl_init_external(req, &req->elem.in_sg[1], &req->elem.in_addr[1], req->elem.in_num - 1); } and this will access out of array bounds. Note: this adds security checks within assert calls since SCSIBusInfo's load_request cannot fail. For now simply disable builds with NDEBUG - there seems to be little value in supporting these. Cc: Andreas Färber Signed-off-by: Michael S. Tsirkin --- hw/scsi/virtio-scsi.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index b0d7517..1752193 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -147,6 +147,15 @@ static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq) qemu_get_be32s(f, &n); assert(n < vs->conf.num_queues); qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem)); + /* TODO: add a way for SCSIBusInfo's load_request to fail, + * and fail migration instead of asserting here. + * When we do, we might be able to re-enable NDEBUG below. + */ +#ifdef NDEBUG +#error building with NDEBUG is not supported +#endif + assert(req->elem.in_num <= ARRAY_SIZE(req->elem.in_sg)); + assert(req->elem.out_num <= ARRAY_SIZE(req->elem.out_sg)); virtio_scsi_parse_req(s, vs->cmd_vqs[n], req); scsi_req_ref(sreq);