[PATCH 4.4 080/114] dm space map common: add bounds check to sm_ll_lookup_bitmap()

[Greg Kroah-Hartman]

From: Joe Thornber <ejt@xxxxxxxxxx>

[ Upstream commit cba23ac158db7f3cd48a923d6861bee2eb7a2978 ]

Corrupted metadata could warrant returning error from sm_ll_lookup_bitmap().

Signed-off-by: Joe Thornber <ejt@xxxxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/md/persistent-data/dm-space-map-common.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index ca09ad2a639c4..6fa4a68e78b0d 100644
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -279,6 +279,11 @@ 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)
-- 
2.34.1