From: "Serge E. Hallyn" <serge@hallyn.com>
To: Aditya Kali <adityakali@google.com>
Cc: tj@kernel.org, lizefan@huawei.com, serge.hallyn@ubuntu.com,
luto@amacapital.net, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
mingo@redhat.com, containers@lists.linux-foundation.org,
jnagal@google.com
Subject: Re: [PATCHv1 7/8] cgroup: cgroup namespace setns support
Date: Thu, 16 Oct 2014 23:12:36 +0200 [thread overview]
Message-ID: <20141016211236.GA4308@mail.hallyn.com> (raw)
In-Reply-To: <1413235430-22944-8-git-send-email-adityakali@google.com>
Quoting Aditya Kali (adityakali@google.com):
> setns on a cgroup namespace is allowed only if
> * task has CAP_SYS_ADMIN in its current user-namespace and
> over the user-namespace associated with target cgroupns.
> * task's current cgroup is descendent of the target cgroupns-root
> cgroup.
What is the point of this?
If I'm a user logged into
/lxc/c1/user.slice/user-1000.slice/session-c12.scope and I start
a container which is in
/lxc/c1/user.slice/user-1000.slice/session-c12.scope/x1
then I will want to be able to enter the container's cgroup.
The container's cgroup root is under my own (satisfying the
below condition0 but my cgroup is not a descendent of the
container's cgroup.
> * target cgroupns-root is same as or deeper than task's current
> cgroupns-root. This is so that the task cannot escape out of its
> cgroupns-root. This also ensures that setns() only makes the task
> get restricted to a deeper cgroup hierarchy.
>
> Signed-off-by: Aditya Kali <adityakali@google.com>
> ---
> kernel/cgroup_namespace.c | 44 ++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/cgroup_namespace.c b/kernel/cgroup_namespace.c
> index c16604f..c612946 100644
> --- a/kernel/cgroup_namespace.c
> +++ b/kernel/cgroup_namespace.c
> @@ -80,8 +80,48 @@ err_out:
>
> static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
> {
> - pr_info("setns not supported for cgroup namespace");
> - return -EINVAL;
> + struct cgroup_namespace *cgroup_ns = ns;
> + struct task_struct *task = current;
> + struct cgroup *cgrp = NULL;
> + int err = 0;
> +
> + if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN) ||
> + !ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + /* Prevent cgroup changes for this task. */
> + threadgroup_lock(task);
> +
> + cgrp = get_task_cgroup(task);
> +
> + err = -EINVAL;
> + if (!cgroup_on_dfl(cgrp))
> + goto out_unlock;
> +
> + /* Allow switch only if the task's current cgroup is descendant of the
> + * target cgroup_ns->root_cgrp.
> + */
> + if (!cgroup_is_descendant(cgrp, cgroup_ns->root_cgrp))
> + goto out_unlock;
> +
> + /* Only allow setns to a cgroupns root-ed deeper than task's current
> + * cgroupns-root. This will make sure that tasks cannot escape their
> + * cgroupns by attaching to parent cgroupns.
> + */
> + if (!cgroup_is_descendant(cgroup_ns->root_cgrp,
> + task_cgroupns_root(task)))
> + goto out_unlock;
> +
> + err = 0;
> + get_cgroup_ns(cgroup_ns);
> + put_cgroup_ns(nsproxy->cgroup_ns);
> + nsproxy->cgroup_ns = cgroup_ns;
> +
> +out_unlock:
> + threadgroup_unlock(current);
> + if (cgrp)
> + cgroup_put(cgrp);
> + return err;
> }
>
> static void *cgroupns_get(struct task_struct *task)
> --
> 2.1.0.rc2.206.gedb03e5
>
> --
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> Please read the FAQ at http://www.tux.org/lkml/
next prev parent reply other threads:[~2014-10-16 21:12 UTC|newest]
Thread overview: 157+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <adityakali-cgroupns>
2014-07-17 19:52 ` [PATCH 0/5] RFC: CGroup Namespaces Aditya Kali
2014-07-17 19:52 ` [PATCH 1/5] kernfs: Add API to get generate relative kernfs path Aditya Kali
2014-07-24 15:10 ` Serge Hallyn
2014-07-17 19:52 ` [PATCH 2/5] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace Aditya Kali
2014-07-24 17:01 ` Serge Hallyn
2014-07-31 19:48 ` Aditya Kali
2014-08-04 23:12 ` Serge Hallyn
2014-07-17 19:52 ` [PATCH 3/5] cgroup: add function to get task's cgroup on default hierarchy Aditya Kali
2014-07-24 16:59 ` Serge Hallyn
2014-07-17 19:52 ` [PATCH 4/5] cgroup: export cgroup_get() and cgroup_put() Aditya Kali
2014-07-24 17:03 ` Serge Hallyn
2014-07-17 19:52 ` [PATCH 5/5] cgroup: introduce cgroup namespaces Aditya Kali
2014-07-17 19:57 ` Andy Lutomirski
2014-07-17 20:55 ` Aditya Kali
2014-07-18 16:51 ` Andy Lutomirski
2014-07-18 18:51 ` Aditya Kali
2014-07-18 18:57 ` Andy Lutomirski
2014-07-21 22:11 ` Aditya Kali
2014-07-21 22:16 ` Andy Lutomirski
2014-07-23 19:52 ` Aditya Kali
2014-07-18 16:00 ` [PATCH 0/5] RFC: CGroup Namespaces Serge Hallyn
2014-07-24 16:10 ` Serge Hallyn
2014-07-24 16:36 ` Serge Hallyn
2014-07-25 19:29 ` Aditya Kali
2014-07-25 20:27 ` Andy Lutomirski
2014-07-29 4:51 ` Serge E. Hallyn
2014-07-29 15:08 ` Andy Lutomirski
2014-07-29 16:06 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 0/8] " Aditya Kali
2014-10-13 21:23 ` [PATCHv1 1/8] kernfs: Add API to generate relative kernfs path Aditya Kali
2014-10-16 16:07 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 2/8] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace Aditya Kali
2014-10-16 16:08 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 3/8] cgroup: add function to get task's cgroup on default hierarchy Aditya Kali
2014-10-16 16:13 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 4/8] cgroup: export cgroup_get() and cgroup_put() Aditya Kali
2014-10-16 16:14 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 5/8] cgroup: introduce cgroup namespaces Aditya Kali
2014-10-16 16:37 ` Serge E. Hallyn
2014-10-24 1:03 ` Aditya Kali
2014-10-25 3:16 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 6/8] cgroup: restrict cgroup operations within task's cgroupns Aditya Kali
2014-10-17 9:28 ` Serge E. Hallyn
2014-10-22 19:06 ` Aditya Kali
2014-10-19 4:57 ` Eric W. Biederman
2014-10-13 21:23 ` [PATCHv1 7/8] cgroup: cgroup namespace setns support Aditya Kali
2014-10-16 21:12 ` Serge E. Hallyn [this message]
2014-10-16 21:17 ` Andy Lutomirski
2014-10-16 21:22 ` Aditya Kali
2014-10-16 21:47 ` Serge E. Hallyn
2014-10-19 5:23 ` Eric W. Biederman
2014-10-19 18:26 ` Andy Lutomirski
2014-10-20 4:55 ` Eric W.Biederman
2014-10-21 0:20 ` Andy Lutomirski
2014-10-21 4:49 ` Eric W. Biederman
2014-10-21 5:03 ` Andy Lutomirski
2014-10-21 5:42 ` Eric W. Biederman
2014-10-21 5:49 ` Andy Lutomirski
2014-10-21 18:49 ` Aditya Kali
2014-10-21 19:02 ` Andy Lutomirski
2014-10-21 22:33 ` Aditya Kali
2014-10-21 22:42 ` Andy Lutomirski
2014-10-22 0:46 ` Aditya Kali
2014-10-22 0:58 ` Andy Lutomirski
2014-10-22 18:37 ` Aditya Kali
2014-10-22 18:50 ` Andy Lutomirski
2014-10-22 19:42 ` Tejun Heo
2014-10-17 9:52 ` Serge E. Hallyn
2014-10-13 21:23 ` [PATCHv1 8/8] cgroup: mount cgroupns-root when inside non-init cgroupns Aditya Kali
2014-10-17 12:19 ` Serge E. Hallyn
2014-10-14 22:42 ` [PATCHv1 0/8] CGroup Namespaces Andy Lutomirski
2014-10-14 23:33 ` Aditya Kali
2014-10-19 4:54 ` Eric W. Biederman
2015-07-22 18:10 ` Vincent Batts
2014-10-31 19:18 ` [PATCHv2 0/7] " Aditya Kali
2014-10-31 19:18 ` [PATCHv2 1/7] kernfs: Add API to generate relative kernfs path Aditya Kali
2014-10-31 19:18 ` [PATCHv2 2/7] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace Aditya Kali
2014-10-31 19:18 ` [PATCHv2 3/7] cgroup: add function to get task's cgroup on default hierarchy Aditya Kali
2014-10-31 19:18 ` [PATCHv2 4/7] cgroup: export cgroup_get() and cgroup_put() Aditya Kali
2014-10-31 19:18 ` [PATCHv2 5/7] cgroup: introduce cgroup namespaces Aditya Kali
2014-11-01 0:02 ` Andy Lutomirski
2014-11-01 0:58 ` Eric W. Biederman
2014-11-03 23:42 ` Aditya Kali
2014-11-03 23:40 ` Aditya Kali
2014-11-04 1:56 ` Aditya Kali
2014-10-31 19:19 ` [PATCHv2 6/7] cgroup: cgroup namespace setns support Aditya Kali
2014-10-31 19:19 ` [PATCHv2 7/7] cgroup: mount cgroupns-root when inside non-init cgroupns Aditya Kali
2014-11-01 0:07 ` Andy Lutomirski
2014-11-01 2:59 ` Eric W. Biederman
2014-11-01 3:29 ` Andy Lutomirski
2014-11-03 23:12 ` Aditya Kali
2014-11-03 23:15 ` Andy Lutomirski
2014-11-03 23:23 ` Aditya Kali
2014-11-03 23:48 ` Andy Lutomirski
2014-11-04 0:12 ` Aditya Kali
2014-11-04 0:17 ` Andy Lutomirski
2014-11-04 0:49 ` Aditya Kali
2014-11-04 13:57 ` Tejun Heo
2014-11-06 17:28 ` Aditya Kali
2014-11-01 1:09 ` Eric W. Biederman
2014-11-03 22:46 ` Aditya Kali
[not found] ` <CAGr1F2Hd_PS_AscBGMXdZC9qkHGRUp-MeQvJksDOQkRBB3RGoA@mail.gmail.com>
2014-11-03 22:56 ` Andy Lutomirski
2014-11-04 13:46 ` Tejun Heo
2014-11-04 15:00 ` Andy Lutomirski
2014-11-04 15:50 ` Serge E. Hallyn
2014-11-12 17:48 ` Aditya Kali
2014-11-04 1:59 ` Aditya Kali
2014-11-04 13:10 ` [PATCHv2 0/7] CGroup Namespaces Vivek Goyal
2014-11-06 17:33 ` Aditya Kali
2014-11-26 22:58 ` Richard Weinberger
2014-12-02 19:14 ` Aditya Kali
2014-12-05 1:55 ` [PATCHv3 0/8] " Aditya Kali
2014-12-05 1:55 ` [PATCHv3 1/8] kernfs: Add API to generate relative kernfs path Aditya Kali
2014-12-05 1:55 ` [PATCHv3 2/8] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace Aditya Kali
2014-12-05 1:55 ` [PATCHv3 3/8] cgroup: add function to get task's cgroup on default hierarchy Aditya Kali
2014-12-05 1:55 ` [PATCHv3 4/8] cgroup: export cgroup_get() and cgroup_put() Aditya Kali
2014-12-05 1:55 ` [PATCHv3 5/8] cgroup: introduce cgroup namespaces Aditya Kali
2014-12-12 8:54 ` Zefan Li
2014-12-05 1:55 ` [PATCHv3 6/8] cgroup: cgroup namespace setns support Aditya Kali
2014-12-05 1:55 ` [PATCHv3 7/8] cgroup: mount cgroupns-root when inside non-init cgroupns Aditya Kali
2014-12-12 8:55 ` Zefan Li
2014-12-05 1:55 ` [PATCHv3 8/8] cgroup: Add documentation for cgroup namespaces Aditya Kali
2014-12-12 8:54 ` Zefan Li
2015-01-05 22:54 ` Aditya Kali
2014-12-14 23:05 ` Richard Weinberger
2015-01-05 22:48 ` Aditya Kali
2015-01-05 22:52 ` Richard Weinberger
2015-01-05 23:53 ` Eric W. Biederman
2015-01-06 0:07 ` Richard Weinberger
2015-01-06 0:10 ` Aditya Kali
2015-01-06 0:17 ` Richard Weinberger
2015-01-06 23:20 ` Aditya Kali
2015-01-06 23:39 ` Richard Weinberger
2015-01-07 9:28 ` Richard Weinberger
2015-01-07 14:45 ` Eric W. Biederman
2015-01-07 19:30 ` Serge E. Hallyn
2015-01-07 22:14 ` Eric W. Biederman
2015-01-07 22:45 ` Tejun Heo
2015-01-07 23:02 ` Eric W. Biederman
2015-01-07 23:06 ` Tejun Heo
2015-01-07 23:09 ` Eric W. Biederman
2015-01-07 23:16 ` Tejun Heo
2015-01-07 23:27 ` Eric W. Biederman
2015-01-07 23:35 ` Tejun Heo
2015-02-11 3:46 ` Serge E. Hallyn
2015-02-11 4:09 ` Tejun Heo
2015-02-11 4:29 ` Serge E. Hallyn
2015-02-11 5:02 ` Eric W. Biederman
2015-02-11 5:17 ` Tejun Heo
2015-02-11 6:29 ` Eric W. Biederman
2015-02-11 14:36 ` Tejun Heo
2015-02-11 16:00 ` Serge E. Hallyn
2015-02-11 16:03 ` Tejun Heo
2015-02-11 16:18 ` Serge E. Hallyn
2015-02-11 5:10 ` Tejun Heo
2015-01-07 18:57 ` Aditya Kali
2014-12-05 3:20 ` [PATCHv3 0/8] CGroup Namespaces Aditya Kali
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