From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54626) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WkwYB-0003Pw-Le for qemu-devel@nongnu.org; Thu, 15 May 2014 10:22:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WkwY6-0003dK-NJ for qemu-devel@nongnu.org; Thu, 15 May 2014 10:22:23 -0400 From: Kevin Wolf Date: Thu, 15 May 2014 16:21:57 +0200 Message-Id: <1400163717-1898-6-git-send-email-kwolf@redhat.com> In-Reply-To: <1400163717-1898-1-git-send-email-kwolf@redhat.com> References: <1400163717-1898-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PATCH v2 5/5] qcow1: Stricter backing file length check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, benoit.canet@irqsave.net, qemu-stable@nongnu.org, stefanha@redhat.com, ppandit@redhat.com Like qcow2 since commit 6d33e8e7, error out on invalid lengths instead of silently truncating them to 1023. Also don't rely on bdrv_pread() catching integer overflows that make len negative, but use unsigned variables in the first place. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf Reviewed-by: Benoit Canet --- block/qcow.c | 7 +++++-- tests/qemu-iotests/092 | 11 +++++++++++ tests/qemu-iotests/092.out | 7 +++++++ 3 files changed, 23 insertions(+), 2 deletions(-) diff --git a/block/qcow.c b/block/qcow.c index 3566c05..7fd57d7 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -97,7 +97,8 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { BDRVQcowState *s = bs->opaque; - int len, i, shift, ret; + unsigned int len, i, shift; + int ret; QCowHeader header; ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); @@ -202,7 +203,9 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags, if (header.backing_file_offset != 0) { len = header.backing_file_size; if (len > 1023) { - len = 1023; + error_setg(errp, "Backing file name too long"); + ret = -EINVAL; + goto fail; } ret = bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len); diff --git a/tests/qemu-iotests/092 b/tests/qemu-iotests/092 index ae6ca76..a8c0c9c 100755 --- a/tests/qemu-iotests/092 +++ b/tests/qemu-iotests/092 @@ -43,6 +43,8 @@ _supported_fmt qcow _supported_proto generic _supported_os Linux +offset_backing_file_offset=8 +offset_backing_file_size=16 offset_size=24 offset_cluster_bits=32 offset_l2_bits=33 @@ -81,6 +83,15 @@ poke_file "$TEST_IMG" "$offset_size" "\xee\xee\xee\xee\xee\xee\xee\xee" poke_file "$TEST_IMG" "$offset_size" "\x7f\xff\xff\xff\xff\xff\xff\xff" { $QEMU_IO -c "write 0 64M" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +echo +echo "== Invalid backing file length ==" +_make_test_img 64M +poke_file "$TEST_IMG" "$offset_backing_file_offset" "\x00\x00\x00\xff" +poke_file "$TEST_IMG" "$offset_backing_file_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_backing_file_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 diff --git a/tests/qemu-iotests/092.out b/tests/qemu-iotests/092.out index ac03302..496d8f0 100644 --- a/tests/qemu-iotests/092.out +++ b/tests/qemu-iotests/092.out @@ -28,4 +28,11 @@ qemu-io: can't open device TEST_DIR/t.qcow: Image too large no file open, try 'help open' qemu-io: can't open device TEST_DIR/t.qcow: Image too large no file open, try 'help open' + +== Invalid backing file length == +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qemu-io: can't open device TEST_DIR/t.qcow: Backing file name too long +no file open, try 'help open' +qemu-io: can't open device TEST_DIR/t.qcow: Backing file name too long +no file open, try 'help open' *** done -- 1.8.3.1