socketiod does not validate the console token, keeps a single global PTY
and broadcasts its output to every connected client, so anyone who can
reach port 6081 can read and write a serial console that someone opened.
It is also broken for legitimate users, since console/views.py now writes
signed tokens that socketiod cannot parse.
Until it is rewritten, turn the serial console off by default:
- Add SERIAL_CONSOLE_ENABLED = False to the settings template; installs
whose settings.py lacks it are treated as disabled.
- The console view shows an error instead of the xterm page for pty
consoles while the setting is off.
- socketiod refuses to start unless SERIAL_CONSOLE_ENABLED is True.
- Supervisor: autostart=false for socketiod; drop -d (debug) from the
supervisor and systemd definitions; fix the systemd unit description;
conf/systemd/install.sh no longer suggests enabling socketiod.
- README: stop opening port 6081 and document how to enable the serial
console on a trusted network.
