From 24342f2cae47d03911e346fe1e520b00dc2818e0 Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 26 Mar 2014 13:05:41 +0100 Subject: [PATCH] qcow2: Check header_length (CVE-2014-0144) This fixes an unbounded allocation for s->unknown_header_fields. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz Signed-off-by: Stefan Hajnoczi --- block/qcow2.c | 34 +++++++++++++++++++------- tests/qemu-iotests/080 | 61 ++++++++++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/080.out | 9 +++++++ tests/qemu-iotests/group | 1 + 4 files changed, 96 insertions(+), 9 deletions(-) create mode 100755 tests/qemu-iotests/080 create mode 100644 tests/qemu-iotests/080.out diff --git a/block/qcow2.c b/block/qcow2.c index 10eccf91e1..7809f5cab4 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -460,6 +460,18 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, s->qcow_version = header.version; + /* Initialise cluster size */ + if (header.cluster_bits < MIN_CLUSTER_BITS || + header.cluster_bits > MAX_CLUSTER_BITS) { + error_setg(errp, "Unsupported cluster size: 2^%i", header.cluster_bits); + ret = -EINVAL; + goto fail; + } + + s->cluster_bits = header.cluster_bits; + s->cluster_size = 1 << s->cluster_bits; + s->cluster_sectors = 1 << (s->cluster_bits - 9); + /* Initialise version 3 header fields */ if (header.version == 2) { header.incompatible_features = 0; @@ -473,6 +485,18 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, be64_to_cpus(&header.autoclear_features); be32_to_cpus(&header.refcount_order); be32_to_cpus(&header.header_length); + + if (header.header_length < 104) { + error_setg(errp, "qcow2 header too short"); + ret = -EINVAL; + goto fail; + } + } + + if (header.header_length > s->cluster_size) { + error_setg(errp, "qcow2 header exceeds cluster size"); + ret = -EINVAL; + goto fail; } if (header.header_length > sizeof(header)) { @@ -530,12 +554,6 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, } s->refcount_order = header.refcount_order; - if (header.cluster_bits < MIN_CLUSTER_BITS || - header.cluster_bits > MAX_CLUSTER_BITS) { - error_setg(errp, "Unsupported cluster size: 2^%i", header.cluster_bits); - ret = -EINVAL; - goto fail; - } if (header.crypt_method > QCOW_CRYPT_AES) { error_setg(errp, "Unsupported encryption method: %i", header.crypt_method); @@ -546,9 +564,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, if (s->crypt_method_header) { bs->encrypted = 1; } - s->cluster_bits = header.cluster_bits; - s->cluster_size = 1 << s->cluster_bits; - s->cluster_sectors = 1 << (s->cluster_bits - 9); + s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ s->l2_size = 1 << s->l2_bits; bs->total_sectors = header.size / 512; diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080 new file mode 100755 index 0000000000..6512701e1e --- /dev/null +++ b/tests/qemu-iotests/080 @@ -0,0 +1,61 @@ +#!/bin/bash +# +# qcow2 format input validation tests +# +# Copyright (C) 2013 Red Hat, Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . +# + +# creator +owner=kwolf@redhat.com + +seq=`basename $0` +echo "QA output created by $seq" + +here=`pwd` +tmp=/tmp/$$ +status=1 # failure is the default! + +_cleanup() +{ + _cleanup_test_img +} +trap "_cleanup; exit \$status" 0 1 2 3 15 + +# get standard environment, filters and checks +. ./common.rc +. ./common.filter + +_supported_fmt qcow2 +_supported_proto generic +_supported_os Linux + +header_size=104 +offset_header_size=100 +offset_ext_magic=$header_size +offset_ext_size=$((header_size + 4)) + +echo +echo "== Huge header size ==" +_make_test_img 64M +poke_file "$TEST_IMG" "$offset_header_size" "\xff\xff\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +poke_file "$TEST_IMG" "$offset_header_size" "\x7f\xff\xff\xff" +{ $QEMU_IO -c "read 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + +# success, all done +echo "*** done" +rm -f $seq.full +status=0 diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out new file mode 100644 index 0000000000..41a166a27f --- /dev/null +++ b/tests/qemu-iotests/080.out @@ -0,0 +1,9 @@ +QA output created by 080 + +== Huge header size == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-io: can't open device TEST_DIR/t.qcow2: qcow2 header exceeds cluster size +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow2: qcow2 header exceeds cluster size +no file open, try 'help open' +*** done diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group index 9c99edc449..ed44f355af 100644 --- a/tests/qemu-iotests/group +++ b/tests/qemu-iotests/group @@ -85,6 +85,7 @@ 077 rw auto quick 078 rw auto 079 rw auto +080 rw auto 081 rw auto 082 rw auto quick 083 rw auto -- 2.11.0