diff options
| author | Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> | 2019-02-27 16:14:30 +0300 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2019-05-07 17:14:21 +0200 |
| commit | a5fff8d4b4d928311a5005efa12d0991fe3b66f9 (patch) | |
| tree | 23e9fcc05dc61c55bed7705ae09430959c692cd0 /tests/qemu-iotests/138 | |
| parent | 7e3e736cbd37a633ed5673de4254424745fbf520 (diff) | |
qcow2-refcount: avoid eating RAM
qcow2_inc_refcounts_imrt() (through realloc_refcount_array()) can eat
an unpredictable amount of memory on corrupted table entries, which are
referencing regions far beyond the end of file.
Prevent this, by skipping such regions from further processing.
Interesting that iotest 138 checks exactly the behavior which we fix
here. So, change the test appropriately.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190227131433.197063-3-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'tests/qemu-iotests/138')
| -rwxr-xr-x | tests/qemu-iotests/138 | 12 |
1 files changed, 5 insertions, 7 deletions
diff --git a/tests/qemu-iotests/138 b/tests/qemu-iotests/138 index f353ac8219..6a731370db 100755 --- a/tests/qemu-iotests/138 +++ b/tests/qemu-iotests/138 @@ -54,15 +54,13 @@ $QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io # Put the data cluster at a multiple of 2 TB, resulting in the image apparently # having a multiple of 2^32 clusters # (To be more specific: It is at 32 PB) -poke_file "$TEST_IMG" 2048 "\x80\x80\x00\x00\x00\x00\x00\x00" +poke_file "$TEST_IMG" $((2048 + 8)) "\x00\x80\x00\x00\x00\x00\x00\x00" # An offset of 32 PB results in qemu-img check having to allocate an in-memory -# refcount table of 128 TB (16 bit refcounts, 512 byte clusters). -# This should be generally too much for any system and thus fail. -# What this test is checking is that the qcow2 driver actually tries to allocate -# such a large amount of memory (and is consequently aborting) instead of having -# truncated the cluster count somewhere (which would result in much less memory -# being allocated and then a segfault occurring). +# refcount table of 128 TB (16 bit refcounts, 512 byte clusters), if qemu-img +# don't check that referenced data cluster is far beyond the end of file. +# But starting from 4.0, qemu-img does this check, and instead of "Cannot +# allocate memory", we have an error showing that l2 entry is invalid. _check_test_img # success, all done |