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btrfs: fix extent map use-after-free when handling missing device in read_one_chunk

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Store the error code before freeing the extent_map. Though it's
reference counted structure, in that function it's the first and last
allocation so this would lead to a potential use-after-free.

The error can happen eg. when chunk is stored on a missing device and
the degraded mount option is missing.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216721
Reported-by: eriri <1527030098@qq.com>
Fixes: adfb69af7d8c ("btrfs: add_missing_dev() should return the actual error")
CC: stable@vger.kernel.org # 4.9+
Signed-off-by: void0red <void0red@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
void0red 2022-11-23 22:39:45 +08:00 committed by David Sterba
parent 3eb4234424
commit 1742e1c90c
1 changed files with 2 additions and 1 deletions
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3
fs/btrfs/volumes.c
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@ -6976,8 +6976,9 @@ 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;
}
}