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btrfs: fix off-by-one when checking chunk map includes logical address 

commit 5fba5a5718 upstream.

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 <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Filipe Manana 2023-11-21 13:38:32 +00:00 committed by Greg Kroah-Hartman
parent d5103edac4
commit 2590e30370
1 changed files with 1 additions and 1 deletions
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2
fs/btrfs/volumes.c
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@ -2823,7 +2823,7 @@ static struct extent_map *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);