From patchwork Wed Mar 26 12:06:04 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 333899 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 BEE86140083 for ; Thu, 27 Mar 2014 00:30:58 +1100 (EST) Received: from localhost ([::1]:48042 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSnuy-0000ml-Ry for incoming@patchwork.ozlabs.org; Wed, 26 Mar 2014 09:30:56 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50720) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSmcC-0002HW-JQ for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:07:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSmc6-0004FL-1M for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:07:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12210) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSmc5-0004Ez-OZ; Wed, 26 Mar 2014 08:07:21 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s2QC7KPW017642 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 26 Mar 2014 08:07:20 -0400 Received: from localhost (dhcp-64-106.muc.redhat.com [10.32.64.106]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s2QC7J5i010270; Wed, 26 Mar 2014 08:07:20 -0400 From: Stefan Hajnoczi To: Date: Wed, 26 Mar 2014 13:06:04 +0100 Message-Id: <1395835569-21193-43-git-send-email-stefanha@redhat.com> In-Reply-To: <1395835569-21193-1-git-send-email-stefanha@redhat.com> References: <1395835569-21193-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , pmatouse@redhat.com, qemu-stable@nongnu.org Subject: [Qemu-devel] [PATCH for-2.0 42/47] qcow2: Fix NULL dereference in qcow2_open() error path (CVE-2014-0146) 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 From: Kevin Wolf The qcow2 code assumes that s->snapshots is non-NULL if s->nb_snapshots != 0. By having the initialisation of both fields separated in qcow2_open(), any error occuring in between would cause the error path to dereference NULL in qcow2_free_snapshots() if the image had any snapshots. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block/qcow2.c | 7 ++++--- tests/qemu-iotests/080 | 7 +++++++ tests/qemu-iotests/080.out | 4 ++++ 3 files changed, 15 insertions(+), 3 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 6c54e2b..7a75398 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -636,9 +636,6 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } - s->snapshots_offset = header.snapshots_offset; - s->nb_snapshots = header.nb_snapshots; - /* read the level 1 table */ if (header.l1_size > 0x2000000) { /* 32 MB L1 table is enough for 2 PB images at 64k cluster size @@ -733,6 +730,10 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, bs->backing_file[len] = '\0'; } + /* Internal snapshots */ + s->snapshots_offset = header.snapshots_offset; + s->nb_snapshots = header.nb_snapshots; + ret = qcow2_read_snapshots(bs); if (ret < 0) { error_setg_errno(errp, -ret, "Could not read snapshots"); diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080 index 56f8903..59e7a44 100755 --- a/tests/qemu-iotests/080 +++ b/tests/qemu-iotests/080 @@ -139,6 +139,13 @@ poke_file "$TEST_IMG" "$offset_l1_size" "\x00\x00\x00\x01" { $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir echo +echo "== Invalid L1 table (with internal snapshot in the image) ==" +_make_test_img 64M +{ $QEMU_IMG snapshot -c foo $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +poke_file "$TEST_IMG" "$offset_l1_size" "\x00\x00\x00\x00" +_img_info + +echo echo "== Invalid backing file size ==" _make_test_img 64M poke_file "$TEST_IMG" "$offset_backing_file_offset" "\x00\x00\x00\x00\x00\x00\x10\x00" diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out index 303d6c3..4d84fbf 100644 --- a/tests/qemu-iotests/080.out +++ b/tests/qemu-iotests/080.out @@ -59,6 +59,10 @@ no file open, try 'help open' qemu-io: can't open device TEST_DIR/t.qcow2: Invalid L1 table offset no file open, try 'help open' +== Invalid L1 table (with internal snapshot in the image) == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-img: Could not open 'TEST_DIR/t.IMGFMT': L1 table is too small + == Invalid backing file size == Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 qemu-io: can't open device TEST_DIR/t.qcow2: Backing file name too long