Files
DECNET/templates/mysql/server.py
anti 55896b0caa Add RFC 5424 syslog logging to all service templates
- decnet/logging/syslog_formatter.py: RFC 5424 formatter (local0 facility,
  decnet@55555 SD element ID, full escaping per §6.3.3)
- decnet/logging/file_handler.py: rotating file handler (10 MB / 5 backups),
  path configurable via DECNET_LOG_FILE env var
- templates/decnet_logging.py: combined syslog_line / write_syslog_file /
  forward_syslog helper distributed to all 22 service template dirs
- All templates/*/server.py: replaced ad-hoc JSON _forward/_log with RFC 5424
  syslog_line + write_syslog_file + forward_syslog
- All templates/*/Dockerfile: COPY decnet_logging.py /opt/
- DecnetConfig: added log_file field; CLI: --log-file flag;
  composer injects DECNET_LOG_FILE env var into service containers
- tests/test_syslog_formatter.py + tests/test_file_handler.py: 25 new tests

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-04-04 04:31:00 -03:00

111 lines
4.0 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 json
import os
import socket
import struct
from datetime import datetime, timezone
from decnet_logging 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", "")
_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)
print(line, flush=True)
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 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", 3306)
async with server:
await server.serve_forever()
if __name__ == "__main__":
asyncio.run(main())