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[Qemu-devel] [PATCH 1/2] qcow2: Fix qemu-img check segfault on corrupted
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PATCH 1/2] qcow2: Fix qemu-img check segfault on corrupted images |
Date: |
Tue, 22 Jun 2010 12:37:54 +0200 |
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 <address@hidden>
---
block/qcow2-refcount.c | 14 +++++++++++---
1 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index c2d0e61..cedf57e 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -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]);
}
}
}
--
1.6.6.1