Re: [patch 07/10] unprivileged mounts: add sysctl tunable for "safe" property

[Miklos Szeredi <miklos@szeredi.hu>]

> > +	t->table[0].mode = 0644;
> 
> Yikes, this could be a problem for containers, as it's simply tied to
> uid 0, whereas tying it to a capability would let us solve it with
> capability bounds.
> 
> This might mean more urgency to get user namespaces working at least
> with sysfs, else this is a quick way around having CAP_SYS_ADMIN taken
> out of a container's capability bounding set.

I think I understand the problem, but not the solution.  How do user
namespaces going to help?

Maybe sysctls just need to check capabilities, instead of uids.  I
think that would make a lot of sense anyway.

Thanks,
Miklos