From: David Sterba dsterba@suse.com

stable inclusion from stable-v5.4.274 commit 576164bd01bd795f8b09fb194b493103506b33c9 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QGIP CVE: CVE-2024-35936

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream commit 7411055db5ce64f836aaffd422396af0075fdc99 ]

The unhandled case in btrfs_relocate_sys_chunks() loop is a corruption, as it could be caused only by two impossible conditions:

- at first the search key is set up to look for a chunk tree item, with offset -1, this is an inexact search and the key->offset will contain the correct offset upon a successful search, a valid chunk tree item cannot have an offset -1

- after first successful search, the found_key corresponds to a chunk item, the offset is decremented by 1 before the next loop, it's impossible to find a chunk item there due to alignment and size constraints

Reviewed-by: Josef Bacik josef@toxicpanda.com Reviewed-by: Anand Jain anand.jain@oracle.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/btrfs/volumes.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 054468e43228..172cec8a12dd 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -2922,7 +2922,17 @@ static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info) mutex_unlock(&fs_info->delete_unused_bgs_mutex); goto error; } - BUG_ON(ret == 0); /* Corruption */ + if (ret == 0) { + /* + * On the first search we would find chunk tree with + * offset -1, which is not possible. On subsequent + * loops this would find an existing item on an invalid + * offset (one less than the previous one, wrong + * alignment and size). + */ + ret = -EUCLEAN; + goto error; + }

ret = btrfs_previous_item(chunk_root, path, key.objectid, key.type);