Files
DECNET/templates/mysql/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

112 lines
4.1 KiB
Python

#!/usr/bin/env python3
"""
MySQLserver.
Sends a realistic MySQL 5.7 server handshake, reads the client login
packet, extracts username, then closes with Access Denied. Logs auth
attempts 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", "dbserver")
SERVICE_NAME = "mysql"
LOG_TARGET = os.environ.get("LOG_TARGET", "")
PORT = int(os.environ.get("PORT", "3306"))
_MYSQL_VER = os.environ.get("MYSQL_VERSION", "5.7.38-log")
# Minimal MySQL server greeting (protocol v10) — version string is configurable
_GREETING = (
b"\x0a" # protocol version 10
+ _MYSQL_VER.encode() + b"\x00" # server version + NUL
+ b"\x01\x00\x00\x00" # connection id = 1
+ b"\x70\x76\x21\x6d\x61\x67\x69\x63" # auth-plugin-data part 1
+ b"\x00" # filler
+ b"\xff\xf7" # capability flags low
+ b"\x21" # charset utf8
+ b"\x02\x00" # status flags
+ b"\xff\x81" # capability flags high
+ b"\x15" # auth plugin data length
+ b"\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" # reserved (10 bytes)
+ b"\x21\x4f\x7d\x25\x3e\x55\x4d\x7c\x67\x75\x5e\x31\x00" # auth part 2
+ b"mysql_native_password\x00" # auth plugin name
)
def _make_packet(payload: bytes, seq: int = 0) -> bytes:
length = len(payload)
return struct.pack("<I", length)[:3] + bytes([seq]) + payload
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 MySQLProtocol(asyncio.Protocol):
def __init__(self):
self._transport = None
self._peer = None
self._buf = b""
self._greeted = False
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])
transport.write(_make_packet(_GREETING, seq=0))
self._greeted = True
def data_received(self, data):
self._buf += data
# MySQL packets: 3-byte length + 1-byte seq + payload
while len(self._buf) >= 4:
length = struct.unpack("<I", self._buf[:3] + b"\x00")[0]
if length > 1024 * 1024:
self._transport.close()
self._buf = b""
return
if len(self._buf) < 4 + length:
break
payload = self._buf[4:4 + length]
self._buf = self._buf[4 + length:]
self._handle_packet(payload)
def _handle_packet(self, payload: bytes):
if not payload:
return
# Login packet: capability flags (4), max_packet (4), charset (1), reserved (23), username (NUL-terminated)
if len(payload) > 32:
try:
# skip capability(4) + max_pkt(4) + charset(1) + reserved(23) = 32 bytes
username_start = 32
nul = payload.index(b"\x00", username_start)
username = payload[username_start:nul].decode(errors="replace")
except (ValueError, IndexError):
username = "<parse_error>"
_log("auth", src=self._peer[0], username=username)
# Send Access Denied error
err = b"\xff" + struct.pack("<H", 1045) + b"#28000Access denied for user\x00"
self._transport.write(_make_packet(err, seq=2))
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"MySQL server starting as {NODE_NAME}")
loop = asyncio.get_running_loop()
server = await loop.create_server(MySQLProtocol, "0.0.0.0", PORT) # nosec B104
async with server:
await server.serve_forever()
if __name__ == "__main__":
asyncio.run(main())