4 files changed, 62 insertions, 0 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f1dd4b076210..d6504338e284 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6421,12 +6421,18 @@ static void cgroupns_put(struct ns_common *ns)
         put_cgroup_ns(to_cg_ns(ns));
 }
 
+static struct user_namespace *cgroupns_owner(struct ns_common *ns)
+{
+        return to_cg_ns(ns)->user_ns;
+}
+
 const struct proc_ns_operations cgroupns_operations = {
         .name           = "cgroup",
         .type           = CLONE_NEWCGROUP,
         .get            = cgroupns_get,
         .put            = cgroupns_put,
         .install        = cgroupns_install,
+        .owner          = cgroupns_owner,
 };
 
 static __init int cgroup_namespaces_init(void)
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 7542b28cc929..df9e8e9e0be7 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -405,12 +405,37 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns)
         return 0;
 }
 
+static struct ns_common *pidns_get_parent(struct ns_common *ns)
+{
+        struct pid_namespace *active = task_active_pid_ns(current);
+        struct pid_namespace *pid_ns, *p;
+
+        /* See if the parent is in the current namespace */
+        pid_ns = p = to_pid_ns(ns)->parent;
+        for (;;) {
+                if (!p)
+                        return ERR_PTR(-EPERM);
+                if (p == active)
+                        break;
+                p = p->parent;
+        }
+
+        return &get_pid_ns(pid_ns)->ns;
+}
+
+static struct user_namespace *pidns_owner(struct ns_common *ns)
+{
+        return to_pid_ns(ns)->user_ns;
+}
+
 const struct proc_ns_operations pidns_operations = {
         .name           = "pid",
         .type           = CLONE_NEWPID,
         .get            = pidns_get,
         .put            = pidns_put,
         .install        = pidns_install,
+        .owner          = pidns_owner,
+        .get_parent     = pidns_get_parent,
 };
 
 static __init int pid_namespaces_init(void)
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)
diff --git a/kernel/utsname.c b/kernel/utsname.c
index 35587b76faa3..6976cd47dcf6 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -154,10 +154,16 @@ static int utsns_install(struct nsproxy *nsproxy, struct ns_common *new)
         return 0;
 }
 
+static struct user_namespace *utsns_owner(struct ns_common *ns)
+{
+        return to_uts_ns(ns)->user_ns;
+}
+
 const struct proc_ns_operations utsns_operations = {
         .name           = "uts",
         .type           = CLONE_NEWUTS,
         .get            = utsns_get,
         .put            = utsns_put,
         .install        = utsns_install,
+        .owner          = utsns_owner,
 };