Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: invalidate dentry cache on failed whiteout creation F2FS can mount filesystems with corrupted directory depth values that get runtime-clamped to MAX_DIR_HASH_DEPTH. When RENAME_WHITEOUT operations are performed on such directories, f2fs_rename performs directory modifications (updating target entry and deleting source entry) before attempting to add the whiteout entry via f2fs_add_link. If f2fs_add_link fails due to the corrupted directory structure, the function returns an error to VFS, but the partial directory modifications have already been committed to disk. VFS assumes the entire rename operation failed and does not update the dentry cache, leaving stale mappings. In the error path, VFS does not call d_move() to update the dentry cache. This results in new_dentry still pointing to the old inode (new_inode) which has already had its i_nlink decremented to zero. The stale cache causes subsequent operations to incorrectly reference the freed inode. This causes subsequent operations to use cached dentry information that no longer matches the on-disk state. When a second rename targets the same entry, VFS attempts to decrement i_nlink on the stale inode, which may already have i_nlink=0, triggering a WARNING in drop_nlink(). Example sequence: 1. First rename (RENAME_WHITEOUT): file2 → file1 - f2fs updates file1 entry on disk (points to inode 8) - f2fs deletes file2 entry on disk - f2fs_add_link(whiteout) fails (corrupted directory) - Returns error to VFS - VFS does not call d_move() due to error - VFS cache still has: file1 → inode 7 (stale!) - inode 7 has i_nlink=0 (already decremented) 2. Second rename: file3 → file1 - VFS uses stale cache: file1 → inode 7 - Tries to drop_nlink on inode 7 (i_nlink already 0) - WARNING in drop_nlink() Fix this by explicitly invalidating old_dentry and new_dentry when f2fs_add_link fails during whiteout creation. This forces VFS to refresh from disk on subsequent operations, ensuring cache consistency even when the rename partially succeeds. Reproducer: 1. Mount F2FS image with corrupted i_current_depth 2. renameat2(file2, file1, RENAME_WHITEOUT) 3. renameat2(file3, file1, 0) 4. System triggers WARNING in drop_nlink()
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < 7f2bae0c881aa1e0a6318756df692cc13df2cc83affected7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < 3d95ed8cf980fdfa67a3ab9491357521ae576168affected7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < 64587ab4d1f16fc94f70e04fa87b2e3f69f8a7bbaffected7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < 3d65e27e57aaa9d66709fda4cbfb62a87c04a3f5affected7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < c89845fae250efdd59c1d4ec60e9e1c652cee4b6affected7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < 0dde30753c1e8648665dbe069d814e540ce2fd37affected7e01e7ad746bc8198a8b46163ddc73a1c7d22339 to < d33f89b34aa313f50f9a512d58dd288999f246b0affected
Linux Linux
Default version status: affected
4.2affected0 to < 4.2unaffected5.10.248 to ≤ 5.10.*unaffected5.15.198 to ≤ 5.15.*unaffected6.1.160 to ≤ 6.1.*unaffected6.6.120 to ≤ 6.6.*unaffected6.12.64 to ≤ 6.12.*unaffected6.18.3 to ≤ 6.18.*unaffected6.19 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/7f2bae0c881aa1e0a6318756df692cc13df2cc83 ↗
- https://git.kernel.org/stable/c/3d95ed8cf980fdfa67a3ab9491357521ae576168 ↗
- https://git.kernel.org/stable/c/64587ab4d1f16fc94f70e04fa87b2e3f69f8a7bb ↗
- https://git.kernel.org/stable/c/3d65e27e57aaa9d66709fda4cbfb62a87c04a3f5 ↗
- https://git.kernel.org/stable/c/c89845fae250efdd59c1d4ec60e9e1c652cee4b6 ↗
- https://git.kernel.org/stable/c/0dde30753c1e8648665dbe069d814e540ce2fd37 ↗
- https://git.kernel.org/stable/c/d33f89b34aa313f50f9a512d58dd288999f246b0 ↗