diff options
| author | Alberto Garcia <berto@igalia.com> | 2017-11-03 16:18:51 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2017-11-14 18:06:25 +0100 |
| commit | 9883975050deffc147a3903d07ff995ecdc8a100 (patch) | |
| tree | 9e1257d6dccbbf925a35ede332beeb3234dd94b9 | |
| parent | 6bf45d59f98c898b7d7997a333765c8ee41236ea (diff) | |
| download | qemu-9883975050deffc147a3903d07ff995ecdc8a100.tar.gz | |
qcow2: Prevent allocating L2 tables at offset 0
If the refcount data is corrupted then we can end up trying to
allocate a new L2 table at offset 0 in the image, triggering an
assertion in the qcow2 cache that would crash QEMU:
qcow2_cache_entry_mark_dirty: Assertion `c->entries[i].offset != 0' failed
This patch adds an explicit check for this scenario and a new test
case.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 92dac37191ae7844a2da22c122204eb493cc3133.1509718618.git.berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
| -rw-r--r-- | block/qcow2-cluster.c | 8 | ||||
| -rwxr-xr-x | tests/qemu-iotests/060 | 7 | ||||
| -rw-r--r-- | tests/qemu-iotests/060.out | 6 |
3 files changed, 21 insertions, 0 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index fb10e26068..2e072ed155 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -278,6 +278,14 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table) goto fail; } + /* If we're allocating the table at offset 0 then something is wrong */ + if (l2_offset == 0) { + qcow2_signal_corruption(bs, true, -1, -1, "Preventing invalid " + "allocation of L2 table at offset 0"); + ret = -EIO; + goto fail; + } + ret = qcow2_cache_flush(bs, s->refcount_block_cache); if (ret < 0) { goto fail; diff --git a/tests/qemu-iotests/060 b/tests/qemu-iotests/060 index dead26aeaf..40f85cc216 100755 --- a/tests/qemu-iotests/060 +++ b/tests/qemu-iotests/060 @@ -253,6 +253,13 @@ poke_file "$TEST_IMG" "$rt_offset" "\x00\x00\x00\x00\x00\x00\x00\x00" # causing a refcount block to be allocated at offset 0 $QEMU_IO -c "write 0 128k" "$TEST_IMG" | _filter_qemu_io +echo +echo "=== Testing empty refcount block ===" +echo +_make_test_img 64M +poke_file "$TEST_IMG" "$rb_offset" "\x00\x00\x00\x00\x00\x00\x00\x00" +$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io + # success, all done echo "*** done" rm -f $seq.full diff --git a/tests/qemu-iotests/060.out b/tests/qemu-iotests/060.out index 872719009c..5b8b518486 100644 --- a/tests/qemu-iotests/060.out +++ b/tests/qemu-iotests/060.out @@ -189,4 +189,10 @@ wrote 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: Preventing invalid allocation of refcount block at offset 0; further corruption events will be suppressed write failed: Input/output error + +=== Testing empty refcount block === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 +qcow2: Marking image as corrupt: Preventing invalid allocation of L2 table at offset 0; further corruption events will be suppressed +write failed: Input/output error *** done |