kernel: tty: n_gsm: require CAP_NET_ADMIN to attach N_GSM0710 ldisc

In the Linux kernel, the following vulnerability has been resolved: tty: ngsm: require CAPNETADMIN to attach NGSM0710 ldisc Any unprivileged user can attach NGSM0710 ldisc, but it requires CAPNETADMIN to create a GSM network anyway. Require initial namespace CAPNETADMIN to do that...