diff mbox series

[1/8] btrfs: fix off-by-one when checking chunk map includes logical address

Message ID db822a05a08d66879288a91f2186a0898dd7e58b.1700573313.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: add a btrfs_chunk_map structure and preparatory cleanups | expand

Commit Message

Filipe Manana Nov. 21, 2023, 1:38 p.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

At btrfs_get_chunk_map() we get the extent map for the chunk that contains
the given logical address stored in the 'logical' argument. Then we do
sanity checks to verify the extent map contains the logical address. One
of these checks verifies if the extent map covers a range with an end
offset behind the target logical address - however this check has an
off-by-one error since it will consider an extent map whose start offset
plus its length matches the target logical address as inclusive, while
the fact is that the last byte it covers is behind the target logical
address (by 1).

So fix this condition by using '<=' rather than '<' when comparing the
extent map's "start + length" against the target logical address.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/volumes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index dd279241f78c..1775ae0998b0 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3008,7 +3008,7 @@  struct extent_map *btrfs_get_chunk_map(struct btrfs_fs_info *fs_info,
 		return ERR_PTR(-EINVAL);
 	}
 
-	if (em->start > logical || em->start + em->len < logical) {
+	if (em->start > logical || em->start + em->len <= logical) {
 		btrfs_crit(fs_info,
 			   "found a bad mapping, wanted %llu-%llu, found %llu-%llu",
 			   logical, length, em->start, em->start + em->len);