Re: [RFC][PATCH] cgroup: Add new capability to allow a process to migrate other tasks between cgroups

From: John Stultz
Date: Tue Oct 04 2016 - 23:00:24 EST

On Tue, Oct 4, 2016 at 5:38 PM, Serge E. Hallyn <serge@xxxxxxxxxx> wrote:
> Quoting John Stultz (john.stultz@xxxxxxxxxx):
>> So this patch, as suggested by Tejun, simply adds a new process
>> capability flag (CAP_CGROUP_MIGRATE_TASK), and uses it when checking
> So realistically, what all can this mean? Freezing tasks, changing
> cpu/memory limits, changing network and disk throughput, forbid forking,
> and (most importantly) forbid access to certain devices.
> I think that's all ok. (And we still separately check for inode write
> perms.)

Sounds good.

> If anything I'd say the GLOBAL_ROOT_UID check could be taken out since
> otherwise a host-root task effectively cannot drop this capability.

Is this ok to leave for a separate patch?

> Acked-by: Serge Hallyn <serge@xxxxxxxxxx>

Thanks for the review!

Unless there's other feedback, I'll sit on this until the merge window
is over and then resubmit for consideration for 4.10.