Message ID | 1395835569-21193-13-git-send-email-stefanha@redhat.com |
---|---|
State | New |
Headers | show |
On 26.03.2014 13:05, Stefan Hajnoczi wrote: > From: Kevin Wolf <kwolf@redhat.com> > > This fixes two possible division by zero crashes: In bochs_open() and in > seek_to_sector(). > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > 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 $seq.full > diff --git a/tests/qemu-iotests/078.out b/tests/qemu-iotests/078.out > index 7254693..ea95ffd 100644 > --- a/tests/qemu-iotests/078.out > +++ b/tests/qemu-iotests/078.out > @@ -15,4 +15,12 @@ no file open, try 'help open' > == Too small catalog bitmap for image size == > qemu-io: can't open device TEST_DIR/empty.bochs: Catalog size is too small for this disk size > no file open, try 'help open' > + > +== Negative extent size == > +qemu-io: can't open device TEST_DIR/empty.bochs: Extent size 4294967295 is too large > +no file open, try 'help open' > + > +== Zero extent size == > +qemu-io: can't open device TEST_DIR/empty.bochs: Extent size may not be zero > +no file open, try 'help open' > *** done Reviewed-by: Max Reitz <mreitz@redhat.com>
diff --git a/block/bochs.c b/block/bochs.c index 0ffa9c1..a922782 100644 --- a/block/bochs.c +++ b/block/bochs.c @@ -148,6 +148,14 @@ static int bochs_open(BlockDriverState *bs, QDict *options, int flags, s->extent_blocks = 1 + (le32_to_cpu(bochs.extent) - 1) / 512; s->extent_size = le32_to_cpu(bochs.extent); + if (s->extent_size == 0) { + error_setg(errp, "Extent size may not be zero"); + return -EINVAL; + } else if (s->extent_size > 0x800000) { + error_setg(errp, "Extent size %" PRIu32 " is too large", + s->extent_size); + return -EINVAL; + } if (s->catalog_size < bs->total_sectors / s->extent_size) { error_setg(errp, "Catalog size is too small for this disk size"); diff --git a/tests/qemu-iotests/078 b/tests/qemu-iotests/078 index 902ef0f..872e734 100755 --- a/tests/qemu-iotests/078 +++ b/tests/qemu-iotests/078 @@ -43,6 +43,7 @@ _supported_proto generic _supported_os Linux catalog_size_offset=$((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