From b2cd8e043a6b66ba225b98b6235fc050f956bf5b Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 25 Mar 2014 14:23:36 +0100 Subject: [PATCH 29/49] qcow2: Check new refcount table size on growth RH-Author: Kevin Wolf Message-id: <1395753835-7591-30-git-send-email-kwolf@redhat.com> Patchwork-id: n/a O-Subject: [virt-devel] [EMBARGOED RHEL-7.0 qemu-kvm PATCH 29/48] qcow2: Check new refcount table size on growth Bugzilla: 1066691 RH-Acked-by: Jeff Cody RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Paolo Bonzini Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1066691 Upstream status: Series embargoed If the size becomes larger than what qcow2_open() would accept, fail the growing operation. Signed-off-by: Kevin Wolf Conflicts: block/qcow2.h 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 c08fb08..7b00dda 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -310,6 +310,10 @@ 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 87f2958..db9f667 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 5efc96e..0173d95 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 (1LL << 63) /* indicate that the cluster is compressed (they never have the copied flag) */ @@ -405,6 +409,11 @@ static inline int64_t align_offset(int64_t offset, int n) return offset; } +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) { -- 1.7.1