linux-kernel - Re: [PATCH v2] cgroup: allow management of subtrees by new cgroup namespaces

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Message-ID: <57271EA8.5080104@suse.de>
Date:	Mon, 2 May 2016 19:32:24 +1000
From:	Aleksa Sarai <asarai@...e.de>
To:	Tejun Heo <tj@...nel.org>, Li Zefan <lizefan@...wei.com>,
	Johannes Weiner <hannes@...xchg.org>
Cc:	cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
	dev@...ncontainers.org, Aleksa Sarai <cyphar@...har.com>
Subject: Re: [PATCH v2] cgroup: allow management of subtrees by new cgroup
 namespaces

> +	 * 3. cgroup core doesn't allow tasks to be migrated by users that have
> +	 *    write access to two subtrees unless they also have write access to
> +	 *    the common ancestor of the two subtrees. Thus you cannot use a
> +	 *    complicit process in less restrictive cgroup to overcome your own
> +	 *    cgroup restriction.

It appears this restriction isn't actually being applied on cgroupv1. 
I'll send an updated patch which makes sure the cgroup.proc common 
ancestor restriction is enforced for all hierarchies.

-- 
Aleksa Sarai
Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/