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authorMax Reitz <mreitz@redhat.com>2017-11-10 21:31:08 +0100
committerMax Reitz <mreitz@redhat.com>2017-11-17 18:21:30 +0100
commit93bbaf03ff7fd490e823814b8f5d6849a7b71a64 (patch)
tree15c255579532a672b067c32e985f7c11b7f16dbd
parent791fff504cad4d935dfaab6333ff9b7d95cbfe3f (diff)
downloadqemu-arm-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.c13
-rwxr-xr-xtests/qemu-iotests/06016
-rw-r--r--tests/qemu-iotests/060.out10
3 files changed, 38 insertions, 1 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 2e072ed..a3fec27 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 56bdf1e..49bc89d 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 f013fe7..c583076 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