Files
DECNET/decnet/services/telnet.py
anti 65d585569b fix(telnet): replace Cowrie with real busybox telnetd + rsyslog logging
Cowrie was exposing an SSH daemon on port 22 alongside the telnet service
even when COWRIE_SSH_ENABLED=false, contaminating deployments that did not
request an SSH service.

New implementation mirrors the SSH service pattern:
- busybox telnetd in foreground mode on port 23
- /bin/login for real PAM authentication (brute-force attempts logged)
- rsyslog RFC 5424 bridge piped to stdout for Docker log capture
- Configurable root password and hostname via env vars
- No Cowrie dependency
2026-04-12 00:34:45 -04:00

48 lines
1.4 KiB
Python

from pathlib import Path
from decnet.services.base import BaseService
TEMPLATES_DIR = Path(__file__).parent.parent.parent / "templates" / "telnet"
class TelnetService(BaseService):
"""
Real telnetd using busybox telnetd + rsyslog logging pipeline.
Replaced Cowrie emulation (which also started an SSH daemon on port 22)
with a real busybox telnetd so only port 23 is exposed and auth events
are logged as RFC 5424 via the same rsyslog bridge used by the SSH service.
service_cfg keys:
password Root password (default: "admin")
hostname Override container hostname
"""
name = "telnet"
ports = [23]
default_image = "build"
def compose_fragment(
self,
decky_name: str,
log_target: str | None = None,
service_cfg: dict | None = None,
) -> dict:
cfg = service_cfg or {}
env: dict = {
"TELNET_ROOT_PASSWORD": cfg.get("password", "admin"),
}
if "hostname" in cfg:
env["TELNET_HOSTNAME"] = cfg["hostname"]
return {
"build": {"context": str(TEMPLATES_DIR)},
"container_name": f"{decky_name}-telnet",
"restart": "unless-stopped",
"cap_add": ["NET_BIND_SERVICE"],
"environment": env,
}
def dockerfile_context(self) -> Path:
return TEMPLATES_DIR