For reasons beyond my control, I have a binary that binds to TCP "localhost:$PORT". (Unix socket bindings would make this question moot).
If I understand correctly, this means that although no network machine can connect, other users on the machine (including unprivileged daemon users) can connect to this port.
Is there some way for me to specify that only binaries running as $me should be allowed to connect to this port? I can become root in order to specify the configuration, but the listening binary and the connecting binaries both run as the non-root $me user