2022-11-23 14:51:35

by void0red

Subject: [PATCH] btrfs: avoid use-after-free when return the error code

free_extent_map(em) will free em->map_lookup, so it is
wrong to use it when return.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216721
Signed-off-by: void0red <[email protected]>
Reported-by: eriri <[email protected]>
---
fs/btrfs/volumes.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 635f45f1a2ef..dba087ad40ea 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -7241,8 +7241,9 @@ static int read_one_chunk(struct btrfs_key *key, struct extent_buffer *leaf,
map->stripes[i].dev = handle_missing_device(fs_info,
devid, uuid);
if (IS_ERR(map->stripes[i].dev)) {
+ ret = PTR_ERR(map->stripes[i].dev);
free_extent_map(em);
- return PTR_ERR(map->stripes[i].dev);
+ return ret;
}
}

--
2.34.1

2022-11-23 16:30:50

by David Sterba

Subject: Re: [PATCH] btrfs: avoid use-after-free when return the error code

On Wed, Nov 23, 2022 at 10:39:45PM +0800, void0red wrote:
> free_extent_map(em) will free em->map_lookup, so it is
> wrong to use it when return.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216721
> Signed-off-by: void0red <[email protected]>
> Reported-by: eriri <[email protected]>

Added to misc-next with updated changelog, thanks.