diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 53dc163..582eb33 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -68,6 +68,7 @@ static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair, QCowSnapshot *sn; int i, id_str_size, name_size; int64_t offset; + uint64_t table_length = 0; int ret; if (!s->nb_snapshots) { @@ -82,6 +83,8 @@ static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair, for(i = 0; i < s->nb_snapshots; i++) { bool truncate_unknown_extra_data = false; + table_length = ROUND_UP(table_length, 8); + /* Read statically sized part of the snapshot header */ offset = ROUND_UP(offset, 8); ret = bdrv_pread(bs->file, offset, &h, sizeof(h)); @@ -184,7 +187,16 @@ static int qcow2_do_read_snapshots(BlockDriverState *bs, bool repair, offset += name_size; sn->name[name_size] = '\0'; - if (offset - s->snapshots_offset > QCOW_MAX_SNAPSHOTS_SIZE) { + /* Note that the extra data may have been truncated */ + table_length += sizeof(h) + sn->extra_data_size + id_str_size + + name_size; + if (!repair) { + assert(table_length == offset - s->snapshots_offset); + } + + if (table_length > QCOW_MAX_SNAPSHOTS_SIZE || + offset - s->snapshots_offset > INT_MAX) + { ret = -EFBIG; error_setg(errp, "Snapshot table is too big"); goto fail; |