From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49923) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSmbR-0000qJ-Uh for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:06:47 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSmbL-0003we-Os for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:06:41 -0400 From: Stefan Hajnoczi Date: Wed, 26 Mar 2014 13:05:34 +0100 Message-Id: <1395835569-21193-13-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> Subject: [Qemu-devel] [PATCH for-2.0 12/47] bochs: Check extent_size header field (CVE-2014-0142) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , pmatouse@redhat.com, qemu-stable@nongnu.org From: Kevin Wolf This fixes two possible division by zero crashes: In bochs_open() and in seek_to_sector(). Signed-off-by: Kevin Wolf Reviewed-by: Stefan Hajnoczi --- block/bochs.c | 8 ++++++++ tests/qemu-iotests/078 | 13 +++++++++++++ tests/qemu-iotests/078.out | 8 ++++++++ 3 files changed, 29 insertions(+) diff --git a/block/bochs.c b/block/bochs.c index 0ffa9c1..a922782 100644 --- a/block/bochs.c +++ b/block/bochs.c @@ -148,6 +148,14 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags, s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512; s->extent_size = le32_to_cpu(bochs.extent); + if (s->extent_size == 0) { + error_setg(errp, "Extent size may not be zero"); + return -EINVAL; + } else if (s->extent_size > 0x800000) { + error_setg(errp, "Extent size %" PRIu32 " is too large", + s->extent_size); + return -EINVAL; + } if (s->catalog_size < bs->total_sectors / s->extent_size) { error_setg(errp, "Catalog size is too small for this disk size"); diff --git a/tests/qemu-iotests/078 b/tests/qemu-iotests/078 index 902ef0f..872e734 100755 --- a/tests/qemu-iotests/078 +++ b/tests/qemu-iotests/078 @@ -43,6 +43,7 @@ _supported_proto generic _supported_os Linux catalog_size_offset=$((0x48)) +extent_size_offset=$((0x50)) disk_size_offset=$((0x58)) echo @@ -68,6 +69,18 @@ _use_sample_img empty.bochs.bz2 poke_file "$TEST_IMG" "$disk_size_offset" "\x00\xc0\x0f\x00\x00\x00\x00\x7f" { $QEMU_IO -c "read 2T 4k" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir +echo +echo "== Negative extent size ==" +_use_sample_img empty.bochs.bz2 +poke_file "$TEST_IMG" "$extent_size_offset" "\xff\xff\xff\xff" +{ $QEMU_IO -c "read 768k 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir + +echo +echo "== Zero extent size ==" +_use_sample_img empty.bochs.bz2 +poke_file "$TEST_IMG" "$extent_size_offset" "\x00\x00\x00\x00" +{ $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/078.out b/tests/qemu-iotests/078.out index 7254693..ea95ffd 100644 --- a/tests/qemu-iotests/078.out +++ b/tests/qemu-iotests/078.out @@ -15,4 +15,12 @@ no file open, try 'help open' == Too small catalog bitmap for image size == qemu-io: can't open device TEST_DIR/empty.bochs: Catalog size is too small for this disk size no file open, try 'help open' + +== Negative extent size == +qemu-io: can't open device TEST_DIR/empty.bochs: Extent size 4294967295 is too large +no file open, try 'help open' + +== Zero extent size == +qemu-io: can't open device TEST_DIR/empty.bochs: Extent size may not be zero +no file open, try 'help open' *** done -- 1.8.5.3