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 /block | |
| parent | 791fff504cad4d935dfaab6333ff9b7d95cbfe3f (diff) | |
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>
Diffstat (limited to 'block')
| -rw-r--r-- | block/qcow2-cluster.c | 13 |
1 files changed, 12 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); |