From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56106) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSuCv-0006CO-HP for qemu-devel@nongnu.org; Wed, 26 Mar 2014 16:13:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSuCp-00044P-H3 for qemu-devel@nongnu.org; Wed, 26 Mar 2014 16:13:53 -0400 Message-ID: <533334F0.3010107@redhat.com> Date: Wed, 26 Mar 2014 21:13:36 +0100 From: Max Reitz MIME-Version: 1.0 References: <1395835569-21193-1-git-send-email-stefanha@redhat.com> <1395835569-21193-13-git-send-email-stefanha@redhat.com> In-Reply-To: <1395835569-21193-13-git-send-email-stefanha@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [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: Stefan Hajnoczi , qemu-devel@nongnu.org Cc: Kevin Wolf , pmatouse@redhat.com, qemu-stable@nongnu.org On 26.03.2014 13:05, Stefan Hajnoczi wrote: > 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", Hm. *g* > + 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 Reviewed-by: Max Reitz