Re: [RFC][PATCH 0/2] Another pass at Android style loosening of cgroup attach permissions
From: Serge E. Hallyn
Date: Tue Oct 04 2016 - 17:26:50 EST
Quoting Tejun Heo (tj@xxxxxxxxxx):
> Hello, Serge.
> On Tue, Oct 04, 2016 at 03:18:40PM -0500, Serge E. Hallyn wrote:
> > how about changing the GLOBAL_ROOT_UID check with a targeted
> > capability check, like
> > if (!ns_capable(tcred->user_ns, CAP_SYS_NICE) &&
> > !uid_eq(cred->euid, tcred->uid) &&
> > !uid_eq(cred->euid, tcred->suid))
> > ret = -EACCES;
> > where the actual capability to use may require some thought.
> Yeah, that's the direction I'm thinking too. We can't use
> CAP_SYS_NICE in general tho. Let's see if a dedicated CAP sticks.
One possibility would be to let each cgroup subsystem define
a move_caps capability mask which is required over the target
task. And add a new CAP_CGROUP which always suffices?