From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41537) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X4Z6n-0004ks-GC for qemu-devel@nongnu.org; Tue, 08 Jul 2014 13:24:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X4Z6B-0000nB-B2 for qemu-devel@nongnu.org; Tue, 08 Jul 2014 13:23:13 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:52043) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X4Z6B-0000mj-41 for qemu-devel@nongnu.org; Tue, 08 Jul 2014 13:22:35 -0400 Received: from /spool/local by e39.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 8 Jul 2014 11:22:34 -0600 From: Michael Roth Date: Tue, 8 Jul 2014 12:18:21 -0500 Message-Id: <1404839947-1086-111-git-send-email-mdroth@linux.vnet.ibm.com> In-Reply-To: <1404839947-1086-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1404839947-1086-1-git-send-email-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 110/156] qcow2: Fix NULL dereference in qcow2_open() error path (CVE-2014-0146) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@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 Signed-off-by: Stefan Hajnoczi (cherry picked from commit 11b128f4062dd7f89b14abc8877ff20d41b28be9) Signed-off-by: Michael Roth --- 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 447308e..52b73a9 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -639,9 +639,6 @@ 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 @@ -736,6 +733,10 @@ 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 -- 1.9.1