kernel: add a helper to get an owning user namespace for a namespace
Return -EPERM if an owning user namespace is outside of a process
current user namespace.
v2: In a first version ns_get_owner returned ENOENT for init_user_ns.
This special cases was removed from this version. There is nothing
outside of init_user_ns, so we can return EPERM.
v3: rename ns->get_owner() to ns->owner(). get_* usually means that it
grabs a reference.
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/fs/namespace.c b/fs/namespace.c
index 7bb2cda..fea56f3 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3348,10 +3348,16 @@
return 0;
}
+static struct user_namespace *mntns_owner(struct ns_common *ns)
+{
+ return to_mnt_ns(ns)->user_ns;
+}
+
const struct proc_ns_operations mntns_operations = {
.name = "mnt",
.type = CLONE_NEWNS,
.get = mntns_get,
.put = mntns_put,
.install = mntns_install,
+ .owner = mntns_owner,
};