CVE-2023-53020 l2tp: close all race conditions in l2tp_tunnel_register()

In the Linux kernel, the following vulnerability has been resolved: l2tp: close all race conditions in l2tptunnelregister The code in l2tptunnelregister is racy in several ways: 1. It modifies the tunnel socket after publishing it. 2. It calls setupudptunnelsock on an existing socket without...