dm space map common: add bounds check to sm_ll_lookup_bitmap()

Corrupted metadata could warrant returning error from sm_ll_lookup_bitmap().

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index 4a6a2a9b4eb49f7cebfd0e172704cac64e70a8c9..bfbfa750e0160341e127cc56f375c47f2afac893 100644 (file)
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -283,6 +283,11 @@ int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result)
        struct disk_index_entry ie_disk;
        struct dm_block *blk;
 
+       if (b >= ll->nr_blocks) {
+               DMERR_LIMIT("metadata block out of bounds");
+               return -EINVAL;
+       }
+
        b = do_div(index, ll->entries_per_block);
        r = ll->load_ie(ll, index, &ie_disk);
        if (r < 0)