From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50356) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WSmbr-0001e7-0z for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:07:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WSmbl-00046C-0U for qemu-devel@nongnu.org; Wed, 26 Mar 2014 08:07:06 -0400 From: Stefan Hajnoczi Date: Wed, 26 Mar 2014 13:05:50 +0100 Message-Id: <1395835569-21193-29-git-send-email-stefanha@redhat.com> In-Reply-To: <1395835569-21193-1-git-send-email-stefanha@redhat.com> References: <1395835569-21193-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH for-2.0 28/47] qcow2: Check new refcount table size on growth List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , pmatouse@redhat.com, qemu-stable@nongnu.org From: Kevin Wolf If the size becomes larger than what qcow2_open() would accept, fail the growing operation. Signed-off-by: Kevin Wolf --- block/qcow2-refcount.c | 4 ++++ block/qcow2.c | 4 +--- block/qcow2.h | 9 +++++++++ 3 files changed, 14 insertions(+), 3 deletions(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index 561d659..1c78ff8 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -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; diff --git a/block/qcow2.c b/block/qcow2.c index 464db5c..6c54e2b 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -608,9 +608,7 @@ 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; diff --git a/block/qcow2.h b/block/qcow2.h index b153505..4015373 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -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) { -- 1.8.5.3