Merge branch 'nsfs-ioctls' into HEAD

[cascardo/linux.git] / kernel / user_namespace.c

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index f2c5ba5..86b7854 100644 (file)
--- 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)