From: Aditya Kali <adityakali@xxxxxxxxxx>
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>
Signed-off-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
---
kernel/cgroup.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 60270b1..2bb58a1 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5952,10 +5952,23 @@ static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
return container_of(ns, struct cgroup_namespace, ns);
}
-static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+static int cgroupns_install(struct nsproxy *nsproxy, struct ns_common *ns)
{
- pr_info("setns not supported for cgroup namespace");
- return -EINVAL;
+ struct cgroup_namespace *cgroup_ns = to_cg_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 struct ns_common *cgroupns_get(struct task_struct *task)
--
1.7.9.5
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