[PATCHv3 6/8] cgroup: cgroup namespace setns support

From: Aditya Kali
Date: Thu Dec 04 2014 - 20:58:43 EST


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.
No implicit cgroup changes happen with attaching to another
cgroupns. It is expected that the somone moves the attaching
process under the target cgroupns-root.

Signed-off-by: Aditya Kali <adityakali@xxxxxxxxxx>
---
kernel/cgroup_namespace.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup_namespace.c b/kernel/cgroup_namespace.c
index 0e0ef3a..ee0cc51 100644
--- a/kernel/cgroup_namespace.c
+++ b/kernel/cgroup_namespace.c
@@ -79,8 +79,21 @@ 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;
+
+ if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN) ||
+ !ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* Don't need to do anything if we are attaching to our own cgroupns. */
+ if (cgroup_ns == nsproxy->cgroup_ns)
+ return 0;
+
+ get_cgroup_ns(cgroup_ns);
+ put_cgroup_ns(nsproxy->cgroup_ns);
+ nsproxy->cgroup_ns = cgroup_ns;
+
+ return 0;
}

static void *cgroupns_get(struct task_struct *task)
--
2.2.0.rc0.207.ga3a616c

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/