diff options
| author | Kevin Wolf <kwolf@redhat.com> | 2010-02-16 15:54:49 +0100 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2010-02-19 15:53:54 -0600 |
| commit | 4805bb66969622f86376191c94c4748bce91e6be (patch) | |
| tree | a93deae6e05d0608f7c5ce6d0e95927ed5a02c9d | |
| parent | 0f853a386739b22e541e6e65ed60a0cb37713340 (diff) | |
qcow2: Fix access after end of array
If a write requests crosses a L2 table boundary and all clusters until the
end of the L2 table are usable for the request, we must not look at the next
L2 entry because we already have arrived at the end of the array.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
| -rw-r--r-- | block/qcow2-cluster.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 3501a94296..b13b6935f8 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -750,12 +750,15 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, while (i < nb_clusters) { i += count_contiguous_clusters(nb_clusters - i, s->cluster_size, &l2_table[l2_index], i, 0); - - if(be64_to_cpu(l2_table[l2_index + i])) + if ((i >= nb_clusters) || be64_to_cpu(l2_table[l2_index + i])) { break; + } i += count_contiguous_free_clusters(nb_clusters - i, &l2_table[l2_index + i]); + if (i >= nb_clusters) { + break; + } cluster_offset = be64_to_cpu(l2_table[l2_index + i]); @@ -763,6 +766,7 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, (cluster_offset & QCOW_OFLAG_COMPRESSED)) break; } + assert(i <= nb_clusters); nb_clusters = i; /* |