fix(packaging): move templates/ into decnet/ package so they ship with pip install
The docker build contexts and syslog_bridge.py lived at repo root, which meant setuptools (include = ["decnet*"]) never shipped them. Agents installed via `pip install $RELEASE_DIR` got site-packages/decnet/** but no templates/, so every deploy blew up in deployer._sync_logging_helper with FileNotFoundError on templates/syslog_bridge.py. Move templates/ -> decnet/templates/ and declare it as setuptools package-data. Path resolutions in services/*.py and engine/deployer.py drop one .parent since templates now lives beside the code. Test fixtures, bandit exclude path, and coverage omit glob updated to match.
This commit is contained in:
265
decnet/templates/smtp/server.py
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265
decnet/templates/smtp/server.py
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#!/usr/bin/env python3
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"""
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SMTP server — emulates a realistic ESMTP server (Postfix-style).
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Two modes of operation, controlled by SMTP_OPEN_RELAY:
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SMTP_OPEN_RELAY=0 (default) — credential harvester
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AUTH attempts are logged and rejected (535).
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RCPT TO is rejected with 554 (relay denied) for all recipients.
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This captures credential stuffing and scanning activity.
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SMTP_OPEN_RELAY=1 — open relay bait
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AUTH is accepted for any credentials (235).
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RCPT TO is accepted for any domain (250).
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DATA is fully buffered until CRLF.CRLF and acknowledged with a
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queued-as message ID. Attractive to spam relay operators.
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The DATA state machine (and the 502-per-line bug) is fixed in both modes.
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"""
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import asyncio
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import base64
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import os
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import random
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import string
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from syslog_bridge import SEVERITY_WARNING, 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 = "smtp"
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LOG_TARGET = os.environ.get("LOG_TARGET", "")
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PORT = int(os.environ.get("PORT", "25"))
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OPEN_RELAY = os.environ.get("SMTP_OPEN_RELAY", "0").strip() == "1"
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_SMTP_BANNER = os.environ.get("SMTP_BANNER", f"220 {NODE_NAME} ESMTP Postfix (Debian/GNU)")
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_SMTP_MTA = os.environ.get("SMTP_MTA", NODE_NAME)
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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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write_syslog_file(line)
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forward_syslog(line, LOG_TARGET)
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def _rand_msg_id() -> str:
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"""Return a Postfix-style 12-char alphanumeric queue ID."""
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chars = string.ascii_uppercase + string.digits
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return "".join(random.choices(chars, k=12))
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def _decode_auth_plain(blob: str) -> tuple[str, str]:
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"""Decode SASL PLAIN: base64(authzid\0authcid\0passwd) → (user, pass)."""
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try:
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decoded = base64.b64decode(blob + "==").decode(errors="replace")
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parts = decoded.split("\x00")
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if len(parts) >= 3:
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return parts[1], parts[2]
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if len(parts) == 2:
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return parts[0], parts[1]
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except Exception:
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pass
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return blob, ""
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class SMTPProtocol(asyncio.Protocol):
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def __init__(self):
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self._transport = None
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self._peer = ("?", 0)
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self._buf = b""
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# per-transaction state
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self._mail_from = ""
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self._rcpt_to: list[str] = []
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# DATA accumulation
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self._in_data = False
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self._data_buf: list[str] = []
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# AUTH multi-step state (LOGIN mechanism sends user/pass in separate lines)
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self._auth_state = "" # "" | "await_user" | "await_pass"
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self._auth_user = ""
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# ── asyncio.Protocol ──────────────────────────────────────────────────────
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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(f"{_SMTP_BANNER}\r\n".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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# Strip trailing \r so both CRLF and bare LF work
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self._handle_line(line.rstrip(b"\r").decode(errors="replace"))
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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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# ── Command dispatch ──────────────────────────────────────────────────────
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def _handle_line(self, line: str) -> None:
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# ── DATA body accumulation ────────────────────────────────────────────
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if self._in_data:
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if line == ".":
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body = "\r\n".join(self._data_buf)
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msg_id = _rand_msg_id()
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_log("message_accepted",
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src=self._peer[0],
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mail_from=self._mail_from,
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rcpt_to=",".join(self._rcpt_to),
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body_bytes=len(body),
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msg_id=msg_id)
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self._transport.write(f"250 2.0.0 Ok: queued as {msg_id}\r\n".encode())
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self._in_data = False
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self._data_buf = []
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self._mail_from = ""
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self._rcpt_to = []
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else:
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# RFC 5321 dot-stuffing: strip leading dot
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self._data_buf.append(line[1:] if line.startswith(".") else line)
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return
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# ── AUTH multi-step (LOGIN / PLAIN continuation) ─────────────────────
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if self._auth_state == "await_plain":
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user, password = _decode_auth_plain(line)
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self._finish_auth(user, password)
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self._auth_state = ""
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return
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if self._auth_state == "await_user":
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self._auth_user = base64.b64decode(line + "==").decode(errors="replace")
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self._auth_state = "await_pass"
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self._transport.write(b"334 UGFzc3dvcmQ6\r\n") # "Password:"
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return
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if self._auth_state == "await_pass":
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password = base64.b64decode(line + "==").decode(errors="replace")
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self._finish_auth(self._auth_user, password)
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self._auth_state = ""
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self._auth_user = ""
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return
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# ── Normal command dispatch ───────────────────────────────────────────
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parts = line.split(None, 1)
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cmd = parts[0].upper() if parts else ""
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args = parts[1] if len(parts) > 1 else ""
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if cmd in ("EHLO", "HELO"):
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if not args:
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self._transport.write(
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f"501 5.5.4 Syntax: {cmd} hostname\r\n".encode()
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)
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return
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_log("ehlo", src=self._peer[0], domain=args)
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self._transport.write(
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f"250-{_SMTP_MTA}\r\n"
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f"250-PIPELINING\r\n"
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f"250-SIZE 10240000\r\n"
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f"250-VRFY\r\n"
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f"250-ETRN\r\n"
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f"250-AUTH PLAIN LOGIN\r\n"
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f"250-ENHANCEDSTATUSCODES\r\n"
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f"250-8BITMIME\r\n"
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f"250 DSN\r\n".encode()
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)
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elif cmd == "AUTH":
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self._handle_auth(args)
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elif cmd == "MAIL":
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addr = args.split(":", 1)[1].strip() if ":" in args else args
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self._mail_from = addr
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_log("mail_from", src=self._peer[0], value=addr)
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self._transport.write(b"250 2.1.0 Ok\r\n")
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elif cmd == "RCPT":
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addr = args.split(":", 1)[1].strip() if ":" in args else args
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if OPEN_RELAY:
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self._rcpt_to.append(addr)
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_log("rcpt_to", src=self._peer[0], value=addr)
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self._transport.write(b"250 2.1.5 Ok\r\n")
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else:
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_log("rcpt_denied", src=self._peer[0], value=addr,
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severity=SEVERITY_WARNING)
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self._transport.write(
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b"554 5.7.1 <" + addr.encode() + b">: Relay access denied\r\n"
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)
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elif cmd == "DATA":
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if not self._rcpt_to:
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self._transport.write(b"503 5.5.1 Error: need RCPT command\r\n")
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else:
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self._in_data = True
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self._transport.write(b"354 End data with <CR><LF>.<CR><LF>\r\n")
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elif cmd == "RSET":
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self._mail_from = ""
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self._rcpt_to = []
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self._in_data = False
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self._data_buf = []
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self._auth_state = ""
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self._auth_user = ""
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self._transport.write(b"250 2.0.0 Ok\r\n")
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elif cmd == "VRFY":
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_log("vrfy", src=self._peer[0], value=args)
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self._transport.write(b"252 2.0.0 Cannot VRFY user\r\n")
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elif cmd == "NOOP":
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self._transport.write(b"250 2.0.0 Ok\r\n")
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elif cmd == "STARTTLS":
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self._transport.write(b"454 4.7.0 TLS not available due to local problem\r\n")
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elif cmd == "QUIT":
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self._transport.write(b"221 2.0.0 Bye\r\n")
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self._transport.close()
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else:
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_log("unknown_command", src=self._peer[0], command=line[:128])
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self._transport.write(b"502 5.5.2 Error: command not recognized\r\n")
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# ── AUTH helpers ──────────────────────────────────────────────────────────
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def _handle_auth(self, args: str) -> None:
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parts = args.split(None, 1)
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mech = parts[0].upper() if parts else ""
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initial = parts[1] if len(parts) > 1 else ""
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if mech == "PLAIN":
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if initial:
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user, password = _decode_auth_plain(initial)
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self._finish_auth(user, password)
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else:
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# Client will send credentials on next line
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self._auth_state = "await_plain"
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self._transport.write(b"334 \r\n")
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elif mech == "LOGIN":
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if initial:
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self._auth_user = base64.b64decode(initial + "==").decode(errors="replace")
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self._auth_state = "await_pass"
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self._transport.write(b"334 UGFzc3dvcmQ6\r\n") # "Password:"
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else:
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self._auth_state = "await_user"
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self._transport.write(b"334 VXNlcm5hbWU6\r\n") # "Username:"
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else:
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self._transport.write(b"504 5.5.4 Unrecognized authentication mechanism\r\n")
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def _finish_auth(self, username: str, password: str) -> None:
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_log("auth_attempt", src=self._peer[0],
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username=username, password=password,
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severity=SEVERITY_WARNING)
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if OPEN_RELAY:
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self._transport.write(b"235 2.7.0 Authentication successful\r\n")
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else:
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self._transport.write(b"535 5.7.8 Error: authentication failed\r\n")
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async def main():
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mode = "open-relay" if OPEN_RELAY else "credential-harvester"
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_log("startup", msg=f"SMTP server starting as {NODE_NAME} ({mode})")
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loop = asyncio.get_running_loop()
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server = await loop.create_server(SMTPProtocol, "0.0.0.0", PORT) # nosec B104
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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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Block a user