Files
DECNET/templates/postgres/server.py
anti 8dd4c78b33 refactor: strip DECNET tokens from container-visible surface
Rename the container-side logging module decnet_logging → syslog_bridge
(canonical at templates/syslog_bridge.py, synced into each template by
the deployer). Drop the stale per-template copies; setuptools find was
picking them up anyway. Swap useradd/USER/chown "decnet" for "logrelay"
so no obvious token appears in the rendered container image.

Apply the same cloaking pattern to the telnet template that SSH got:
syslog pipe moves to /run/systemd/journal/syslog-relay and the relay
is cat'd via exec -a "systemd-journal-fwd". rsyslog.d conf rename
99-decnet.conf → 50-journal-forward.conf. SSH capture script:
/var/decnet/captured → /var/lib/systemd/coredump (real systemd path),
logger tag decnet-capture → systemd-journal. Compose volume updated
to match the new in-container quarantine path.

SD element ID shifts decnet@55555 → relay@55555; synced across
collector, parser, sniffer, prober, formatter, tests, and docs so the
host-side pipeline still matches what containers emit.
2026-04-17 22:57:53 -04:00

120 lines
4.1 KiB
Python

#!/usr/bin/env python3
"""
PostgreSQLserver.
Reads the startup message, extracts username and database, responds with
an AuthenticationMD5Password challenge, logs the hash sent back, then
returns an error. Logs all interactions as JSON.
"""
import asyncio
import os
import struct
from syslog_bridge import syslog_line, write_syslog_file, forward_syslog
NODE_NAME = os.environ.get("NODE_NAME", "pgserver")
SERVICE_NAME = "postgres"
LOG_TARGET = os.environ.get("LOG_TARGET", "")
PORT = int(os.environ.get("PORT", "5432"))
def _error_response(message: str) -> bytes:
body = b"S" + b"FATAL\x00" + b"M" + message.encode() + b"\x00\x00"
return b"E" + struct.pack(">I", len(body) + 4) + body
def _log(event_type: str, severity: int = 6, **kwargs) -> None:
line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
write_syslog_file(line)
forward_syslog(line, LOG_TARGET)
class PostgresProtocol(asyncio.Protocol):
def __init__(self):
self._transport = None
self._peer = None
self._buf = b""
self._state = "startup"
def connection_made(self, transport):
self._transport = transport
self._peer = transport.get_extra_info("peername", ("?", 0))
_log("connect", src=self._peer[0], src_port=self._peer[1])
def data_received(self, data):
self._buf += data
self._process()
def _process(self):
if self._state == "startup":
if len(self._buf) < 4:
return
msg_len = struct.unpack(">I", self._buf[:4])[0]
if msg_len < 8 or msg_len > 10_000:
self._transport.close()
self._buf = b""
return
if len(self._buf) < msg_len:
return
msg = self._buf[:msg_len]
self._buf = self._buf[msg_len:]
self._handle_startup(msg)
elif self._state == "auth":
if len(self._buf) < 5:
return
msg_type = chr(self._buf[0])
msg_len = struct.unpack(">I", self._buf[1:5])[0]
if msg_len < 4 or msg_len > 10_000:
self._transport.close()
self._buf = b""
return
if len(self._buf) < msg_len + 1:
return
payload = self._buf[5:msg_len + 1]
self._buf = self._buf[msg_len + 1:]
if msg_type == "p":
self._handle_password(payload)
def _handle_startup(self, msg: bytes):
# Startup message: length(4) + protocol_version(4) + params (key=value\0 pairs)
if len(msg) < 8:
return
proto = struct.unpack(">I", msg[4:8])[0]
if proto == 80877103: # SSL request
self._transport.write(b"N") # reject SSL
return
params_raw = msg[8:].split(b"\x00")
params = {}
for i in range(0, len(params_raw) - 1, 2):
k = params_raw[i].decode(errors="replace")
v = params_raw[i + 1].decode(errors="replace") if i + 1 < len(params_raw) else ""
if k:
params[k] = v
username = params.get("user", "")
database = params.get("database", "")
_log("startup", src=self._peer[0], username=username, database=database)
self._state = "auth"
salt = os.urandom(4)
auth_md5 = b"R" + struct.pack(">I", 12) + struct.pack(">I", 5) + salt
self._transport.write(auth_md5)
def _handle_password(self, payload: bytes):
pw_hash = payload.rstrip(b"\x00").decode(errors="replace")
_log("auth", src=self._peer[0], pw_hash=pw_hash)
self._transport.write(_error_response("password authentication failed"))
self._transport.close()
def connection_lost(self, exc):
_log("disconnect", src=self._peer[0] if self._peer else "?")
async def main():
_log("startup", msg=f"PostgreSQL server starting as {NODE_NAME}")
loop = asyncio.get_running_loop()
server = await loop.create_server(PostgresProtocol, "0.0.0.0", PORT) # nosec B104
async with server:
await server.serve_forever()
if __name__ == "__main__":
asyncio.run(main())