Re: [RFC PATCH 1/2] devices cgroup: allow can_attach() if ns_capable

From: Tejun Heo
Date: Thu Oct 24 2013 - 06:57:58 EST


On Wed, Oct 23, 2013 at 12:41:30AM +0000, Serge E. Hallyn wrote:
> Quoting Tejun Heo (tj@xxxxxxxxxx):
> > On Tue, Jul 23, 2013 at 2:38 PM, Serge Hallyn <serge.hallyn@xxxxxxxxxx> wrote:
> > > This doesn't delegate it into the container. It allows me, on the host,
> > > to set the cgroup for a container.
> >
> > Hmmm? I'm a bit confused. Isn't the description saying that the patch
> > allows pseudo-root in userns to change cgroup membership even if it
> > isn't actually root?
> >
> > Besides, I find the whole check rather bogus and would actually much
> > prefer just nuking the check and just follow the standard permission
> > checks.
>
> Can we please nuke it like this then?
>
> From b840083ec8fa1f0645ae925c79db3dc51edd019c Mon Sep 17 00:00:00 2001
> From: Serge Hallyn <serge.hallyn@xxxxxxxxxx>
> Date: Wed, 23 Oct 2013 01:34:00 +0200
> Subject: [PATCH 1/1] device_cgroup: remove can_attach
>
> It is really only wanting to duplicate a check which is already done by the
> cgroup subsystem.
>
> With this patch, user jdoe still cannot move pid 1 into a devices cgroup
> he owns, but now he can move his own other tasks into devices cgroups.
>
> Signed-off-by: Serge Hallyn <serge.hallyn@xxxxxxxxxx>
> Cc: Aristeu Rozanski <aris@xxxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>

Applied to cgroup/for-3.13. Thanks.

--
tejun
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