1 files changed, 25 insertions, 0 deletions

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index f2c5ba5505f1..86b7854fec8e 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1050,12 +1050,37 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
         return commit_creds(cred);
 }
 
+struct ns_common *ns_get_owner(struct ns_common *ns)
+{
+        struct user_namespace *my_user_ns = current_user_ns();
+        struct user_namespace *owner, *p;
+
+        /* See if the owner is in the current user namespace */
+        owner = p = ns->ops->owner(ns);
+        for (;;) {
+                if (!p)
+                        return ERR_PTR(-EPERM);
+                if (p == my_user_ns)
+                        break;
+                p = p->parent;
+        }
+
+        return &get_user_ns(owner)->ns;
+}
+
+static struct user_namespace *userns_owner(struct ns_common *ns)
+{
+        return to_user_ns(ns)->parent;
+}
+
 const struct proc_ns_operations userns_operations = {
         .name           = "user",
         .type           = CLONE_NEWUSER,
         .get            = userns_get,
         .put            = userns_put,
         .install        = userns_install,
+        .owner          = userns_owner,
+        .get_parent     = ns_get_owner,
 };
 
 static __init int user_namespaces_init(void)