anti
24f02c3466
- Add # nosec B104 to all intentional 0.0.0.0 binds in honeypot servers (hardcoded_bind_all_interfaces is by design — deckies must accept attacker connections) - Add # nosec B101 to assert statements used for protocol validation in ldap/snmp - Add # nosec B105 to fake SASL placeholder in ldap - Add # nosec B108 to /tmp usage in smb template - Exclude root-owned auto-generated decnet_logging.py copies from bandit scan via pyproject.toml [tool.bandit] config (synced by _sync_logging_helper at deploy)
135 lines
3.7 KiB
Python
135 lines
3.7 KiB
Python
#!/usr/bin/env python3
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"""
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SIP server (UDP + TCP port 5060).
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Parses SIP REGISTER and INVITE messages, logs credentials from the
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Authorization header and call metadata, then responds with 401 Unauthorized.
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"""
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import asyncio
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import os
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import re
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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", "pbx")
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SERVICE_NAME = "sip"
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LOG_TARGET = os.environ.get("LOG_TARGET", "")
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_401 = (
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"SIP/2.0 401 Unauthorized\r\n"
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"Via: {via}\r\n"
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"From: {from_}\r\n"
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"To: {to}\r\n"
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"Call-ID: {call_id}\r\n"
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"CSeq: {cseq}\r\n"
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'WWW-Authenticate: Digest realm="{host}", nonce="decnet0000", algorithm=MD5\r\n'
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"Content-Length: 0\r\n\r\n"
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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 _parse_headers(msg: str) -> dict:
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headers = {}
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for line in msg.splitlines()[1:]:
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if ":" in line:
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k, _, v = line.partition(":")
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headers[k.strip().lower()] = v.strip()
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return headers
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def _handle_message(data: bytes, src_addr) -> bytes | None:
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try:
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msg = data.decode(errors="replace")
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except Exception:
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return None
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first_line = msg.splitlines()[0] if msg else ""
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method = first_line.split()[0] if first_line else "UNKNOWN"
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headers = _parse_headers(msg)
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auth_header = headers.get("authorization", "")
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username = ""
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if auth_header:
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m = re.search(r'username="([^"]+)"', auth_header)
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username = m.group(1) if m else ""
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_log(
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"request",
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src=src_addr[0],
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src_port=src_addr[1],
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method=method,
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from_=headers.get("from", ""),
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to=headers.get("to", ""),
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username=username,
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auth=auth_header[:256],
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)
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if method in ("REGISTER", "INVITE", "OPTIONS"):
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response = _401.format(
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via=headers.get("via", ""),
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from_=headers.get("from", ""),
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to=headers.get("to", ""),
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call_id=headers.get("call-id", ""),
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cseq=headers.get("cseq", ""),
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host=NODE_NAME,
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)
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return response.encode()
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return None
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class SIPUDPProtocol(asyncio.DatagramProtocol):
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def __init__(self):
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self._transport = None
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def connection_made(self, transport):
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self._transport = transport
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def datagram_received(self, data, addr):
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response = _handle_message(data, addr)
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if response and self._transport:
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self._transport.sendto(response, addr)
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class SIPTCPProtocol(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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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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def data_received(self, data):
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self._buf += data
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if b"\r\n\r\n" in self._buf or b"\n\n" in self._buf:
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response = _handle_message(self._buf, self._peer)
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self._buf = b""
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if response:
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self._transport.write(response)
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def connection_lost(self, exc):
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pass
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async def main():
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_log("startup", msg=f"SIP server starting as {NODE_NAME}")
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loop = asyncio.get_running_loop()
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udp_transport, _ = await loop.create_datagram_endpoint(
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SIPUDPProtocol, local_addr=("0.0.0.0", 5060) # nosec B104
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)
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tcp_server = await loop.create_server(SIPTCPProtocol, "0.0.0.0", 5060) # nosec B104
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async with tcp_server:
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await tcp_server.serve_forever()
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udp_transport.close()
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if __name__ == "__main__":
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asyncio.run(main())
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