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>
This commit is contained in:
Andrey Vagin
2016-09-06 00:47:13 -07:00
committed by Eric W. Biederman
parent 29b4817d40
commit bcac25a58b
9 changed files with 68 additions and 0 deletions

View File

@@ -388,12 +388,18 @@ static int pidns_install(struct nsproxy *nsproxy, struct ns_common *ns)
return 0;
}
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,
};
static __init int pid_namespaces_init(void)