CVE-2025-68266

In the Linux kernel, the following vulnerability has been resolved:

bfs: Reconstruct file type when loading from disk

syzbot is reporting that S_IFMT bits of inode->i_mode can become bogus when

the S_IFMT bits of the 32bits "mode" field loaded from disk are corrupted

or when the 32bits "attributes" field loaded from disk are corrupted.

A documentation says that BFS uses only lower 9 bits of the "mode" field.

But I can't find an explicit explanation that the unused upper 23 bits

(especially, the S_IFMT bits) are initialized with 0.

Therefore, ignore the S_IFMT bits of the "mode" field loaded from disk.

Also, verify that the value of the "attributes" field loaded from disk is

either BFS_VREG or BFS_VDIR (because BFS supports only regular files and

the root directory).