The web app (wsgi.py), novncd and socketiod set SIGCHLD to SIG_IGN at
import. The kernel then reaps every child at once, so subprocess loses
the exit status and a failing command reports 0, in the server and in
anything else run in that process: the test suite had to reset the
signal in two tests.
It was added in 2023 against one defunct bash per gunicorn worker and
per novncd. That bash came from the settings template of the time,
which ran .dec_ldap_pwd.sh with Popen and never waited for it; the
template stopped doing that in 561fedf. A settings.py still holding
that line leaves at most one zombie per process, not a growing number.
- wsgi.py, novncd, socketiod: the global SIG_IGN is removed. subprocess
reaps its own children, websockify installs its own SIGCHLD reaper
for novncd's connection processes, and novncd's SSH tunnels wait for
their ssh process.
- socketiod: the pty child execs consolecallback instead of running it
and then returning into the server's code; disconnect reaps that
child (waitpid) instead of any child (wait).
- The settings template drops its unused subprocess import; the two
test workarounds are removed.
New tests load the web app and novncd in a fresh interpreter and check
that SIGCHLD is untouched and a failing command still returns 1; both
fail on the previous code. A patched novncd in the test container
served five connections and left no child behind.
Comments, docstrings and live test names cited item IDs of a roadmap
that is not part of the repository. They now say what is meant, or
nothing where the sentence stands without them. Test assertions and
behavior are unchanged.
- Comment out the nginx /socket.io/ location: a firewall on 6081 does not
protect a console that nginx proxies on 80/443.
- Default SOCKETIO_HOST to 127.0.0.1.
- README: short enable steps and the changes existing installs need.
- test_socketiod_disabled writes its settings module to a temporary
directory instead of the source tree.
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.
