Re: [PATCH 5/7] ecryptfs: sanitize struct iattr handling in truncate_upper

[Tyler Hicks <code@tyhicks.com>]

On 2026-04-06 08:27:13, Christoph Hellwig wrote:
> On Mon, Apr 06, 2026 at 01:22:53AM -0500, Tyler Hicks wrote:
> > Err... that was a bad suggestion. upper_size should be a loff_t but, now
> > that I'm at the end of the patch series review, I see that's essentially
> > the signature of ecryptfs_truncate() but I'm still not understanding why
> > we're sticking the upper inode size into the lower_ia.
> 
> Because that's what the existing setattr path already does by doing a
> memcpy of the upper ia.  We can explicitly pass it as a separate
> argument, but I'm not really sure that clarifies things as all other
> information gets passed in lower_ia.  I could add a big comment explaining
> all this if it helps?  It took me some time to figure out, so I might as
> well share that with the world.

I think the intent of the current code is to copy all of the existing
iattrs, from upper to lower, but treat lower_ia->ia_size as
"uninitialized" and calculate/initialize it accordingly within
truncate_upper(). I don't think the passed in value of lower_ia->ia_size
was being used anywhere.

I would prefer passing the new upper size as a separate argument.

The end result of this patch series is very nice. Thanks for working on
it!

Tyler