anti
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80 lines
2.6 KiB
Python
80 lines
2.6 KiB
Python
#!/usr/bin/env python3
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"""
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POP3server.
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Presents a convincing POP3 banner, collects USER/PASS credentials, then
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stalls with a generic error. Logs every interaction as JSON and forwards
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to LOG_TARGET if set.
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"""
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import asyncio
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import os
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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", "mailserver")
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SERVICE_NAME = "pop3"
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LOG_TARGET = os.environ.get("LOG_TARGET", "")
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BANNER = f"+OK {NODE_NAME} POP3 server ready\r\n"
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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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class POP3Protocol(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._user = None
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self._buf = b""
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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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transport.write(BANNER.encode())
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def data_received(self, data):
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self._buf += data
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while b"\n" in self._buf:
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line, self._buf = self._buf.split(b"\n", 1)
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self._handle_line(line.decode(errors="replace").strip())
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def _handle_line(self, line: str):
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upper = line.upper()
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if upper.startswith("USER "):
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self._user = line[5:].strip()
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_log("user", src=self._peer[0], username=self._user)
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self._transport.write(b"+OK\r\n")
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elif upper.startswith("PASS "):
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password = line[5:].strip()
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_log("auth", src=self._peer[0], username=self._user, password=password)
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self._transport.write(b"-ERR Authentication failed\r\n")
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elif upper == "QUIT":
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self._transport.write(b"+OK Bye\r\n")
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self._transport.close()
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elif upper == "CAPA":
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self._transport.write(b"+OK Capability list follows\r\nUSER\r\n.\r\n")
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else:
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_log("command", src=self._peer[0], cmd=line[:128])
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self._transport.write(b"-ERR Unknown command\r\n")
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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"POP3 server starting as {NODE_NAME}")
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loop = asyncio.get_running_loop()
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server = await loop.create_server(POP3Protocol, "0.0.0.0", 110)
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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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