From: Tejun Heo <tj@kernel.org>
To: "Michal Koutný" <mkoutny@suse.com>
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
bpf@vger.kernel.org, Aditya Kali <adityakali@google.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Yonghong Song <yhs@fb.com>,
Muneendra Kumar <muneendra.kumar@broadcom.com>,
Yosry Ahmed <yosryahmed@google.com>, Hao Luo <haoluo@google.com>
Subject: Re: [PATCH 0/4] Honor cgroup namespace when resolving cgroup id
Date: Fri, 26 Aug 2022 11:08:04 -1000 [thread overview]
Message-ID: <Ywk2NMwurnBYhU+D@slm.duckdns.org> (raw)
In-Reply-To: <20220826165238.30915-1-mkoutny@suse.com>
Hello,
On Fri, Aug 26, 2022 at 06:52:34PM +0200, Michal Koutný wrote:
> Cgroup id is becoming a new way for userspace how to refer to cgroups it
> wants to act upon. As opposed to cgroupfs (paths, opened FDs), the
> current approach does not reflect limited view by (non-init) cgroup
> namespaces.
Looking at the code, I'm not quite sure we're actually plugging all holes in
terms of lookup. I think cgroup_get_from_path() would allow walking up past
the ns boundary. We aren't using kernfs ns support and I don't see anything
preventing ..'ing past the boundary.
> This patches don't aim to limit what a user can do (consider an uid=0 in
> mere cgroup namespace) but to provide consistent view within a
> namespace.
Considering userns and the fact that we try to isolate two separate sub
hierarchies delegated to the same UID, I think we'd have to tighten down on
the behaviors so that visiblity scope matches the permission scope.
Thanks.
--
tejun
prev parent reply other threads:[~2022-08-26 21:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-26 16:52 [PATCH 0/4] Honor cgroup namespace when resolving cgroup id Michal Koutný
2022-08-26 16:52 ` [PATCH 1/4] cgroup: Honor caller's cgroup NS when resolving path Michal Koutný
2022-08-26 16:52 ` [PATCH 2/4] cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id Michal Koutný
2022-08-26 16:52 ` [PATCH 3/4] cgroup: Homogenize cgroup_get_from_id() return value Michal Koutný
2022-08-26 16:52 ` [PATCH 4/4] cgroup/bpf: Honor cgroup NS in cgroup_iter for ancestors Michal Koutný
2022-08-26 17:41 ` Yosry Ahmed
2022-08-29 12:59 ` Michal Koutný
2022-08-29 17:30 ` Yosry Ahmed
2022-08-29 17:49 ` Tejun Heo
2022-08-29 18:02 ` Hao Luo
2022-08-26 20:59 ` [PATCH 0/4] Honor cgroup namespace when resolving cgroup id Tejun Heo
2022-08-26 21:08 ` Tejun Heo [this message]
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