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qcow2: Fix qemu-img check segfault on corrupted images 

With corrupted images, we can easily get an cluster index that exceeds the
array size of the temporary refcount table.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Kevin Wolf 2010-06-22 12:31:45 +02:00
parent 20a81e4d17
commit 6882c8fa78
1 changed files with 11 additions and 3 deletions
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14
block/qcow2-refcount.c
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@ -1140,22 +1140,30 @@ int qcow2_check_refcounts(BlockDriverState *bs)
s->refcount_table_offset,
s->refcount_table_size * sizeof(uint64_t));
for(i = 0; i < s->refcount_table_size; i++) {
int64_t offset;
uint64_t offset, cluster;
offset = s->refcount_table[i];
cluster = offset >> s->cluster_bits;
/* Refcount blocks are cluster aligned */
if (offset & (s->cluster_size - 1)) {
fprintf(stderr, "ERROR refcount block %d is not "
"cluster aligned; refcount table entry corrupted\n", i);
errors++;
continue;
}
if (cluster >= nb_clusters) {
fprintf(stderr, "ERROR refcount block %d is outside image\n", i);
errors++;
continue;
}
if (offset != 0) {
errors += inc_refcounts(bs, refcount_table, nb_clusters,
offset, s->cluster_size);
if (refcount_table[offset / s->cluster_size] != 1) {
if (refcount_table[cluster] != 1) {
fprintf(stderr, "ERROR refcount block %d refcount=%d\n",
i, refcount_table[offset / s->cluster_size]);
i, refcount_table[cluster]);
}
}
}