Re: [PATCH v2 0/9] procfs: protect /proc//* files with file->f_cred

Djalal Harouni
2013-10-04T09:05:44Z

On Thu, Oct 03, 2013 at 08:12:44AM +0200, Ingo Molnar wrote:
> So please first get consensus on this fundamental design question before
> spreading your solution to more areas.
Check file_ns_capable() added in commit 935d8aabd4331 by Linus
Add file_ns_capable() helper function for open-time capability checking

commit 6708075f104c3c9b0 by Eric,
userns: Don't let unprivileged users trick privileged users into setting
the id_map

So they add file_ns_capable() to inspect file->f_cred during ->write()

The difference between the function I've added proc_allow_access() and
file_ns_capable() is that proc_allow_access() will check if it's
absolutely the same user, otherwise fallback to security_capable() which
is the heart of file_ns_capable()

So it's already been done and proposed! this is an easy solution to
detect if current's cred have changed.

> Thanks,
>
> Ingo

--
Djalal Harouni