138 lines
5.2 KiB
Python
138 lines
5.2 KiB
Python
#!/usr/bin/env python3
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import Milter
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import dkim
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import authres
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import sys
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import configparser
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import os
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import re
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import logging
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from io import BytesIO
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CONFIG_PATH = "/etc/pyarc/milter.conf"
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config = configparser.ConfigParser()
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if not os.path.exists(CONFIG_PATH):
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print(f"Fehler: Konfigurationsdatei nicht gefunden unter {CONFIG_PATH}", file=sys.stderr)
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sys.exit(1)
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config.read(CONFIG_PATH)
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# --- Logging Setup ---
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LOG_ENABLED = config.getboolean("logging", "file_logging", fallback=False)
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LOG_FILE = config.get("logging", "log_file", fallback="/var/log/pyarc/pyarc.log")
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logger = logging.getLogger("pyarc_milter")
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logger.setLevel(logging.INFO)
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stdout_handler = logging.StreamHandler(sys.stdout)
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stdout_formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
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stdout_handler.setFormatter(stdout_formatter)
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logger.addHandler(stdout_handler)
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if LOG_ENABLED:
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log_dir = os.path.dirname(LOG_FILE)
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if not os.path.exists(log_dir):
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try:
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os.makedirs(log_dir, exist_ok=True)
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except Exception as e:
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logger.error(f"Konnte Log-Verzeichnis {log_dir} nicht erstellen: {e}")
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if os.path.exists(log_dir):
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try:
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file_handler = logging.FileHandler(LOG_FILE)
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file_formatter = logging.Formatter('%(asctime)s - %(levelname)s - [%(process)d] - %(message)s')
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file_handler.setFormatter(file_formatter)
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logger.addHandler(file_handler)
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except Exception as e:
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logger.error(f"Konnte Log-Datei {LOG_FILE} nicht öffnen: {e}")
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# --- Allgemeine Config laden ---
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AUTH_SERV_ID = config.get("general", "auth_serv_id", fallback="mx01.domain.tld")
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LISTEN_SOCKET = config.get("general", "listen_socket", fallback="inet:8899@127.0.0.1")
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REJECT_ON_FAIL = config.getboolean("validation", "reject_on_fail", fallback=False)
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DOMAIN_REGEX = re.compile(r'@([a-zA-Z0-9.-]+\.[a-zA-Z]{2,})')
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class ArcMilter(Milter.Base):
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def __init__(self):
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self.id = Milter.uniqueID()
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self.headers = []
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self.body_buffer = BytesIO()
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self.from_domain = None
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def header(self, name, hval):
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self.headers.append((name.encode('utf-8'), hval.encode('utf-8')))
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if name.lower() == 'from':
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match = DOMAIN_REGEX.search(hval)
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if match:
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self.from_domain = match.group(1).lower().strip()
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return Milter.CONTINUE
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def body(self, chunk):
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self.body_buffer.write(chunk)
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return Milter.CONTINUE
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def eom(self):
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self.body_buffer.seek(0)
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full_mail = b"".join([b"%s: %s\r\n" % (k, v) for k, v in self.headers]) + b"\r\n" + self.body_buffer.read()
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try:
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# --- 1. Eingehend: ARC Validierung ---
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arc_verifier = dkim.ARC(full_mail)
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cv, results, comment = arc_verifier.verify()
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cv_str = cv.decode('utf-8') if isinstance(cv, bytes) else str(cv)
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logger.info(f"[{self.id}] Validierung für Domain '{self.from_domain}': CV={cv_str} ({comment})")
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self.addheader('Authentication-Results', f"{AUTH_SERV_ID}; arc={cv_str}")
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is_arc_valid = (cv_str == "pass")
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if cv_str == "fail" and REJECT_ON_FAIL:
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logger.warning(f"[{self.id}] Mail abgewiesen: ARC Validation fehlgeschlagen.")
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self.setreply('550', '5.7.1', 'ARC validation failed')
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return Milter.REJECT
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# --- 2. Ausgehend: Dynamische ARC Signierung ---
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if self.from_domain and config.has_section(self.from_domain):
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selector = config.get(self.from_domain, "selector")
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key_path = config.get(self.from_domain, "private_key_path")
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if os.path.exists(key_path):
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with open(key_path, "rb") as f:
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private_key = f.read()
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sig_headers = dkim.arc_sign(
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full_mail,
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selector=selector.encode('utf-8'),
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domain=self.from_domain.encode('utf-8'),
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privkey=private_key,
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srv_id=AUTH_SERV_ID.encode('utf-8')
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)
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for header_line in sig_headers:
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if b':' in header_line:
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name, val = header_line.split(b':', 1)
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self.addheader(name.decode('utf-8').strip(), val.decode('utf-8').strip())
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logger.info(f"[{self.id}] Mail für {self.from_domain} erfolgreich signiert (Selector: {selector}).")
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is_arc_valid = True
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else:
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logger.error(f"[{self.id}] Key für {self.from_domain} nicht gefunden unter {key_path}")
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self.addheader('X-ARC', 'TRUE' if is_arc_valid else 'FALSE')
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except Exception as e:
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logger.error(f"[{self.id}] Fehler beim ARC-Processing: {e}", exc_info=True)
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return Milter.CONTINUE
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def main():
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Milter.factory = ArcMilter
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logger.info(f"Multidomain ARC Milter startet auf {LISTEN_SOCKET}...")
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Milter.runmilter("ArcMilter", LISTEN_SOCKET, timeout=30)
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if __name__ == "__main__":
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main()
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