Re: [PATCH 3/7] fs: Ignore file caps in mounts from other user namespaces

Seth Forshee
2015-07-16T13:07:15Z

On Wed, Jul 15, 2015 at 06:23:01PM -0700, Andy Lutomirski wrote:
> > So if we have the s_user_ns check in get_file_caps the mnt_may_suid pass
> > isn't strictly necessary, but I still think it is useful as a mitigation
> > to the "leaks" Eric mentions. It _should_ be impossible for a user to
> > gain access to another user's mount namespace,
>
> No, it's very easy with SCM_RIGHTS. We should make sure it's safe.

Sure, what I really meant was that an attacker shouldn't be able to do
so without cooperation from the other user's processes. But I think
we're all in agreement that making it safe is a good idea.

Seth