From qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org Wed Jan 11 03:51:20 2012
Return-Path: <qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org>
Received: from citysiren.linuxtx.org (localhost [127.0.0.1])
by citysiren.linuxtx.org (8.14.4/8.14.4) with ESMTP id q0B9pIjw017454
for <jmfmail@localhost>; Wed, 11 Jan 2012 03:51:20 -0600
Delivered-To: jmforbes@linuxtx.org
Received: from gmail-pop.l.google.com [74.125.81.108]
by citysiren.linuxtx.org with POP3 (fetchmail-6.3.20)
for <jmfmail@localhost> (single-drop); Wed, 11 Jan 2012 03:51:20 -0600 (CST)
Received: by 10.180.102.100 with SMTP id fn4cs34060wib;
Wed, 11 Jan 2012 01:48:56 -0800 (PST)
Received: by 10.224.182.2 with SMTP id ca2mr28967033qab.57.1326275334564;
Wed, 11 Jan 2012 01:48:54 -0800 (PST)
Received: from lists.gnu.org (lists.gnu.org. [140.186.70.17])
by mx.google.com with ESMTPS id gc3si782557qab.44.2012.01.11.01.48.54
(version=TLSv1/SSLv3 cipher=OTHER);
Wed, 11 Jan 2012 01:48:54 -0800 (PST)
Received-SPF: pass (google.com: domain of qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org designates 140.186.70.17 as permitted sender) client-ip=140.186.70.17;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org designates 140.186.70.17 as permitted sender) smtp.mail=qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org
Received: from localhost ([::1]:48473 helo=lists.gnu.org)
by lists.gnu.org with esmtp (Exim 4.71)
(envelope-from <qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org>)
id 1Rkund-0003iT-UQ
for jmforbes@linuxtx.org; Wed, 11 Jan 2012 04:48:53 -0500
Received: from eggs.gnu.org ([140.186.70.92]:40037)
by lists.gnu.org with esmtp (Exim 4.71)
(envelope-from <pbonzini@redhat.com>) id 1RkunV-0003fY-Vl
for qemu-stable@nongnu.org; Wed, 11 Jan 2012 04:48:53 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
(envelope-from <pbonzini@redhat.com>) id 1RkunQ-0004zL-Nl
for qemu-stable@nongnu.org; Wed, 11 Jan 2012 04:48:45 -0500
Received: from mx1.redhat.com ([209.132.183.28]:23781)
by eggs.gnu.org with esmtp (Exim 4.71)
(envelope-from <pbonzini@redhat.com>) id 1RkunQ-0004vY-3c
for qemu-stable@nongnu.org; Wed, 11 Jan 2012 04:48:40 -0500
Received: from int-mx11.intmail.prod.int.phx2.redhat.com
(int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24])
by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q0B9mcYI005348
(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK)
for <qemu-stable@nongnu.org>; Wed, 11 Jan 2012 04:48:38 -0500
Received: from yakj.usersys.redhat.com (ovpn-112-23.ams2.redhat.com
[10.36.112.23])
by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP
id q0B9magG031084
for <qemu-stable@nongnu.org>; Wed, 11 Jan 2012 04:48:37 -0500
From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-stable@nongnu.org
Date: Wed, 11 Jan 2012 10:48:33 +0100
Message-Id: <1326275313-15635-1-git-send-email-pbonzini@redhat.com>
X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24
X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3)
X-Received-From: 209.132.183.28
Subject: [Qemu-stable] [PATCH] virtio-blk: refuse SG_IO requests with
scsi=off
X-BeenThere: qemu-stable@nongnu.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: <qemu-stable.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-stable>,
<mailto:qemu-stable-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-stable>
List-Post: <mailto:qemu-stable@nongnu.org>
List-Help: <mailto:qemu-stable-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-stable>,
<mailto:qemu-stable-request@nongnu.org?subject=subscribe>
Errors-To: qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org
Sender: qemu-stable-bounces+jmforbes=linuxtx.org@nongnu.org
X-UID: 32
Status: RO
Content-Length: 1003
Lines: 38
QEMU does have a "scsi" option (to be used like -device
virtio-blk-pci,drive=foo,scsi=off). However, it only
masks the feature bit, and does not reject the command
if a malicious guest disregards the feature bits and
issues a request.
Without this patch, using scsi=off does not protect you
from CVE-2011-4127.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/virtio-blk.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index b70d116..6cd3164 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -153,6 +153,12 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
int status;
int i;
+ if ((req->dev->vdev.guest_features & (1 << VIRTIO_BLK_F_SCSI)) == 0) {
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
+ qemu_free(req);
+ return;
+ }
+
/*
* We require at least one output segment each for the virtio_blk_outhdr
* and the SCSI command block.
--
1.7.7.1