anti
55896b0caa
- 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>
137 lines
4.5 KiB
Python
137 lines
4.5 KiB
Python
#!/usr/bin/env python3
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"""
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MSSQL (TDS)server.
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Reads TDS pre-login and login7 packets, extracts username, responds with
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a login failed error. Logs auth attempts as JSON.
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"""
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import asyncio
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import json
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import os
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import socket
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import struct
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from datetime import datetime, timezone
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from decnet_logging import syslog_line, write_syslog_file, forward_syslog
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NODE_NAME = os.environ.get("NODE_NAME", "dbserver")
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SERVICE_NAME = "mssql"
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LOG_TARGET = os.environ.get("LOG_TARGET", "")
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# Minimal TDS pre-login response
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_PRELOGIN_RESP = bytes([
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0x04, 0x01, 0x00, 0x2b, 0x00, 0x00, 0x01, 0x00, # TDS header type=4, status=1, len=43
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# VERSION option
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0x00, 0x00, 0x1a, 0x00, 0x06,
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# ENCRYPTION option (not supported = 0x02)
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0x01, 0x00, 0x20, 0x00, 0x01,
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# INSTOPT
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0x02, 0x00, 0x21, 0x00, 0x01,
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# THREADID
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0x03, 0x00, 0x22, 0x00, 0x04,
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# TERMINATOR
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0xff,
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# version data: 16.00.1000
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0x10, 0x00, 0x03, 0xe8, 0x00, 0x00,
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# encryption: NOT_SUP
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0x02,
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# instance name NUL
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0x00,
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# thread id
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0x00, 0x00, 0x00, 0x01,
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])
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def _log(event_type: str, severity: int = 6, **kwargs) -> None:
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line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
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print(line, flush=True)
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write_syslog_file(line)
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forward_syslog(line, LOG_TARGET)
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def _tds_error_packet(message: str) -> bytes:
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msg_enc = message.encode("utf-16-le")
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# Token type 0xAA = ERROR, followed by length, error number, state, class, msg_len, msg
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token = (
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b"\xaa"
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+ struct.pack("<H", 4 + 1 + 1 + 2 + len(msg_enc) + 1 + 1 + 1 + 1 + 4)
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+ struct.pack("<I", 18456) # SQL error number: login failed
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+ b"\x01" # state
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+ b"\x0e" # class
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+ struct.pack("<H", len(message))
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+ msg_enc
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+ b"\x00" # server name length
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+ b"\x00" # proc name length
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+ struct.pack("<I", 1) # line number
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)
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done = b"\xfd\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
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payload = token + done
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header = struct.pack(">BBHBBBB", 0x04, 0x01, len(payload) + 8, 0x00, 0x00, 0x01, 0x00)
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return header + payload
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class MSSQLProtocol(asyncio.Protocol):
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def __init__(self):
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self._transport = None
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self._peer = None
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self._buf = b""
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self._prelogin_done = False
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def connection_made(self, transport):
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self._transport = transport
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self._peer = transport.get_extra_info("peername", ("?", 0))
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_log("connect", src=self._peer[0], src_port=self._peer[1])
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def data_received(self, data):
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self._buf += data
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while len(self._buf) >= 8:
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pkt_type = self._buf[0]
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pkt_len = struct.unpack(">H", self._buf[2:4])[0]
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if len(self._buf) < pkt_len:
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break
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payload = self._buf[8:pkt_len]
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self._buf = self._buf[pkt_len:]
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self._handle_packet(pkt_type, payload)
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def _handle_packet(self, pkt_type: int, payload: bytes):
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if pkt_type == 0x12: # Pre-login
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self._transport.write(_PRELOGIN_RESP)
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self._prelogin_done = True
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elif pkt_type == 0x10: # Login7
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username = self._parse_login7_username(payload)
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_log("auth", src=self._peer[0], username=username)
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self._transport.write(_tds_error_packet("Login failed for user."))
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self._transport.close()
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else:
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_log("unknown_packet", src=self._peer[0], pkt_type=hex(pkt_type))
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self._transport.close()
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def _parse_login7_username(self, payload: bytes) -> str:
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try:
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# Login7 layout: fixed header 36 bytes, then offsets
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# Username offset at bytes 36-37, length at 38-39
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if len(payload) < 40:
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return "<short_packet>"
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offset = struct.unpack("<H", payload[36:38])[0]
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length = struct.unpack("<H", payload[38:40])[0]
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username = payload[offset:offset + length * 2].decode("utf-16-le", errors="replace")
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return username
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except Exception:
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return "<parse_error>"
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def connection_lost(self, exc):
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_log("disconnect", src=self._peer[0] if self._peer else "?")
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async def main():
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_log("startup", msg=f"MSSQL server starting as {NODE_NAME}")
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loop = asyncio.get_running_loop()
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server = await loop.create_server(MSSQLProtocol, "0.0.0.0", 1433)
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async with server:
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await server.serve_forever()
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if __name__ == "__main__":
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asyncio.run(main())
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