From patchwork Tue Apr 1 17:19:02 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 336077 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 7CD1C1400B4 for ; Wed, 2 Apr 2014 04:32:09 +1100 (EST) Received: from localhost ([::1]:33522 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WV2Xf-00021G-FN for incoming@patchwork.ozlabs.org; Tue, 01 Apr 2014 13:32:07 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42119) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WV2My-0001X1-2A for qemu-devel@nongnu.org; Tue, 01 Apr 2014 13:21:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WV2Mp-0003GF-IS for qemu-devel@nongnu.org; Tue, 01 Apr 2014 13:21:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25203) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WV2Mp-0003G9-AZ for qemu-devel@nongnu.org; Tue, 01 Apr 2014 13:20:55 -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 s31HKqBX008887 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 1 Apr 2014 13:20:52 -0400 Received: from localhost (ovpn-112-69.ams2.redhat.com [10.36.112.69]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s31HKpsr007154; Tue, 1 Apr 2014 13:20:51 -0400 From: Stefan Hajnoczi To: Date: Tue, 1 Apr 2014 19:19:02 +0200 Message-Id: <1396372769-11688-25-git-send-email-stefanha@redhat.com> In-Reply-To: <1396372769-11688-1-git-send-email-stefanha@redhat.com> References: <1396372769-11688-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , Peter Maydell , Stefan Hajnoczi Subject: [Qemu-devel] [PULL for-2.0 24/51] qcow2: Check refcount table size (CVE-2014-0144) 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 Limit the in-memory reference count table size to 8 MB, it's enough in practice. This fixes an unbounded allocation as well as a buffer overflow in qcow2_refcount_init(). Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Signed-off-by: Stefan Hajnoczi --- block/qcow2-refcount.c | 4 +++- block/qcow2.c | 9 +++++++++ tests/qemu-iotests/080 | 10 ++++++++++ tests/qemu-iotests/080.out | 7 +++++++ 4 files changed, 29 insertions(+), 1 deletion(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 4a2df5f..e3c7ecd 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -40,8 +40,10 @@ static int QEMU_WARN_UNUSED_RESULT update_refcount(BlockDriverState *bs, int qcow2_refcount_init(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; - int ret, refcount_table_size2, i; + unsigned int refcount_table_size2, i; + int ret; + assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t)); refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t); s->refcount_table = g_malloc(refcount_table_size2); if (s->refcount_table_size > 0) { diff --git a/block/qcow2.c b/block/qcow2.c index f0411a9..b9b6e70 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -577,10 +577,19 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, s->csize_shift = (62 - (s->cluster_bits - 8)); s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; s->cluster_offset_mask = (1LL << s->csize_shift) - 1; + s->refcount_table_offset = header.refcount_table_offset; s->refcount_table_size = header.refcount_table_clusters << (s->cluster_bits - 3); + if (header.refcount_table_clusters > (0x800000 >> s->cluster_bits)) { + /* 8 MB refcount table is enough for 2 PB images at 64k cluster size + * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */ + error_setg(errp, "Reference count table too large"); + ret = -EINVAL; + goto fail; + } + s->snapshots_offset = header.snapshots_offset; s->nb_snapshots = header.nb_snapshots; diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080 index 6d588dd..6179e05 100755 --- a/tests/qemu-iotests/080 +++ b/tests/qemu-iotests/080 @@ -45,6 +45,7 @@ _supported_os Linux header_size=104 offset_backing_file_offset=8 +offset_refcount_table_clusters=56 offset_header_size=100 offset_ext_magic=$header_size offset_ext_size=$((header_size + 4)) @@ -67,6 +68,15 @@ poke_file "$TEST_IMG" "$offset_ext_size" "\x7f\xff\xff\xff" poke_file "$TEST_IMG" "$offset_backing_file_offset" "\x00\x00\x00\x00\x00\x00\x00\x00" { $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +echo +echo "== Huge refcount table size ==" +_make_test_img 64M +poke_file "$TEST_IMG" "$offset_refcount_table_clusters" "\xff\xff\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +poke_file "$TEST_IMG" "$offset_refcount_table_clusters" "\x00\x02\x00\x01" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out index 48c40aa..6fef6d9 100644 --- a/tests/qemu-iotests/080.out +++ b/tests/qemu-iotests/080.out @@ -13,4 +13,11 @@ qemu-io: can't open device TEST_DIR/t.qcow2: Invalid backing file offset no file open, try 'help open' qemu-io: can't open device TEST_DIR/t.qcow2: Header extension too large no file open, try 'help open' + +== Huge refcount table size == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-io: can't open device TEST_DIR/t.qcow2: Reference count table too large +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow2: Reference count table too large +no file open, try 'help open' *** done