diff options
| author | Max Reitz <mreitz@redhat.com> | 2017-11-10 21:31:08 +0100 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2017-11-17 18:21:30 +0100 |
| commit | 93bbaf03ff7fd490e823814b8f5d6849a7b71a64 (patch) | |
| tree | 15c255579532a672b067c32e985f7c11b7f16dbd | |
| parent | 791fff504cad4d935dfaab6333ff9b7d95cbfe3f (diff) | |
| download | qemu-93bbaf03ff7fd490e823814b8f5d6849a7b71a64.tar.gz | |
qcow2: Unaligned zero cluster in handle_alloc()
We should check whether the cluster offset we are about to use is
actually valid; that is, whether it is aligned to cluster boundaries.
Reported-by: R. Nageswara Sastry <nasastry@in.ibm.com>
Buglink: https://bugs.launchpad.net/qemu/+bug/1728643
Buglink: https://bugs.launchpad.net/qemu/+bug/1728657
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20171110203111.7666-3-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
| -rw-r--r-- | block/qcow2-cluster.c | 13 | ||||
| -rwxr-xr-x | tests/qemu-iotests/060 | 16 | ||||
| -rw-r--r-- | tests/qemu-iotests/060.out | 10 |
3 files changed, 38 insertions, 1 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 2e072ed155..a3fec27bf9 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1308,10 +1308,21 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset, (!*host_offset || start_of_cluster(s, *host_offset) == (entry & L2E_OFFSET_MASK))) { + int preallocated_nb_clusters; + + if (offset_into_cluster(s, entry & L2E_OFFSET_MASK)) { + qcow2_signal_corruption(bs, true, -1, -1, "Preallocated zero " + "cluster offset %#llx unaligned (guest " + "offset: %#" PRIx64 ")", + entry & L2E_OFFSET_MASK, guest_offset); + ret = -EIO; + goto fail; + } + /* Try to reuse preallocated zero clusters; contiguous normal clusters * would be fine, too, but count_cow_clusters() above has limited * nb_clusters already to a range of COW clusters */ - int preallocated_nb_clusters = + preallocated_nb_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size, &l2_table[l2_index], QCOW_OFLAG_COPIED); assert(preallocated_nb_clusters > 0); diff --git a/tests/qemu-iotests/060 b/tests/qemu-iotests/060 index 56bdf1ee2e..49bc89df38 100755 --- a/tests/qemu-iotests/060 +++ b/tests/qemu-iotests/060 @@ -321,6 +321,22 @@ echo '--- Repairing ---' # because the image was already marked corrupt by that point _check_test_img -r all +echo +echo "=== Writing to an unaligned preallocated zero cluster ===" +echo + +_make_test_img 64M + +# Allocate the L2 table +$QEMU_IO -c "write 0 64k" -c "discard 0 64k" "$TEST_IMG" | _filter_qemu_io +# Pretend there is a preallocated zero cluster somewhere inside the +# image header +poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x00\x2a\x01" +# Let's write to it! +$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io + +# Can't repair this yet (TODO: We can just deallocate the cluster) + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out index f013fe73c0..c583076808 100644 --- a/tests/qemu-iotests/060.out +++ b/tests/qemu-iotests/060.out @@ -307,4 +307,14 @@ The following inconsistencies were found and repaired: Double checking the fixed image now... No errors were found on the image. + +=== Writing to an unaligned preallocated zero cluster === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +wrote 65536/65536 bytes at offset 0 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +discard 65536/65536 bytes at offset 0 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +qcow2: Marking image as corrupt: Preallocated zero cluster offset 0x2a00 unaligned (guest offset: 0); further corruption events will be suppressed +write failed: Input/output error *** done |