Re: [PATCH bpf-next 2/2] selftests/bpf: Extend test fs_kfuncs to cover security.bpf xattr names

[Christoph Hellwig]

On Wed, Oct 30, 2024 at 08:44:26PM +0000, Song Liu wrote:
> Given bpf kfuncs can read user.* xattrs for almost a year now, I think we 
> cannot simply revert it. We already have some users using it. 
> 
> Instead, we can work on a plan to deprecated it. How about we add a 
> WARN_ON_ONCE as part of this patchset, and then remove user.* support 
> after some time?

As Christian mentioned having bpf access to user xattrs is probably
not a big issue.  OTOH anything that makes security decisions based
on it is probably pretty broken.  Not sure how you want to best
handle that.