New port: sysutils/mac_nonet

Simple MAC framework policy to disable access to networking for
certain group. Running kldload mac_nonet.ko to load the kernel
module. The load action require root permissions.

Set gid that shouldn't access the network:

sysctl security.mac.nonet.gid=31337

and enable enforcing:

sysctl security.mac.nonet.enabled=1

Any call to socket(2) from user in this group will end with EPERM.
You can also select group that can access only AF_UNIX sockets with
security.mac.nonet.local_gid.

WWW: https://github.com/pbiernacki/mac_nonet

PR: 219376
Submitted by: amutu@amutu.com
Reviewed by: bapt