Re: [PATCH] hfs: Validate CNIDs in hfs_read_inode

[Tetsuo Handa]

On 2025/10/29 12:20, George Anthony Vernon wrote:
> I think HFS_POR_CNID case should be disallowed. There is no real
> underlying file with that CNID. If we ever found a record with that CNID
> it would mean the filesystem image was broken, and if we ever try to
> write a record with that CNID, it means we screwed up.

Hmm, your interpretation does not match what Viacheslav Dubeyko interpreted

  hfs_read_inode() can be called for the root directory and parent of
  the root cases. So, HFS_POR_CNID and HFS_ROOT_CNID are legitimate values.

at https://lkml.kernel.org/r/9a18338da59460bd5c95605d8b10f895a0b7dbb8.camel@xxxxxxx .

But if HFS_POR_CNID is not allowed, you can inline is_valid_cnid() for HFS_CDR_DIR case
like https://lkml.kernel.org/r/23498435-ee11-4eb9-9be9-8460a6fa17f1@xxxxxxxxxxxxxxxxxxx .

> I agree your check is good to catch root inode's i_ino > 15 (is this
> reachable?) and I'd like to add it. Would you be happy if I make a
> 2-part patch series with your patch second, keeping your sign-off on it?

OK.