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qcow2: Check new refcount table size on growth 

If the size becomes larger than what qcow2_open() would accept, fail the
growing operation.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf 2014-03-26 13:05:50 +01:00 committed by Stefan Hajnoczi
parent db8a31d11d
commit 2b5d5953ee
3 changed files with 14 additions and 3 deletions
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4
block/qcow2-refcount.c
View File

@ -311,6 +311,10 @@ static int alloc_refcount_block(BlockDriverState *bs,
uint64_t refcount_block_clusters = 1 << (s->cluster_bits - REFCOUNT_SHIFT);
uint64_t blocks_used = DIV_ROUND_UP(cluster_index, refcount_block_clusters);
if (blocks_used > QCOW_MAX_REFTABLE_SIZE / sizeof(uint64_t)) {
return -EFBIG;
}
/* And now we need at least one block more for the new metadata */
uint64_t table_size = next_refcount_table_size(s, blocks_used + 1);
uint64_t last_table_size;

4
block/qcow2.c
View File

@ -609,9 +609,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
s->refcount_table_size =
header.refcount_table_clusters << (s->cluster_bits - 3);
if (header.refcount_table_clusters > (0x800000 >> s->cluster_bits)) {
/* 8 MB refcount table is enough for 2 PB images at 64k cluster size
* (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
if (header.refcount_table_clusters > qcow2_max_refcount_clusters(s)) {
error_setg(errp, "Reference count table too large");
ret = -EINVAL;
goto fail;

9
block/qcow2.h
View File

@ -40,6 +40,10 @@
#define QCOW_MAX_CRYPT_CLUSTERS 32
#define QCOW_MAX_SNAPSHOTS 65536
/* 8 MB refcount table is enough for 2 PB images at 64k cluster size
* (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
#define QCOW_MAX_REFTABLE_SIZE 0x800000
/* indicate that the refcount of the referenced cluster is exactly one. */
#define QCOW_OFLAG_COPIED (1ULL << 63)
/* indicate that the cluster is compressed (they never have the copied flag) */
@ -410,6 +414,11 @@ static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s)
return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
}
static inline uint64_t qcow2_max_refcount_clusters(BDRVQcowState *s)
{
return QCOW_MAX_REFTABLE_SIZE >> s->cluster_bits;
}
static inline int qcow2_get_cluster_type(uint64_t l2_entry)
{
if (l2_entry & QCOW_OFLAG_COMPRESSED) {