From: Filipe Manana Date: Tue, 21 Nov 2023 13:38:32 +0000 (+0000) Subject: btrfs: fix off-by-one when checking chunk map includes logical address X-Git-Tag: v6.7-rc6-pxa1908~137^2~4 X-Git-Url: https://git.dujemihanovic.xyz/?a=commitdiff_plain;h=5fba5a571858ce2d787fdaf55814e42725bfa895;p=linux.git btrfs: fix off-by-one when checking chunk map includes logical address 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. CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- 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);