385 lines
18 KiB
Python
385 lines
18 KiB
Python
# PyQuarantine-Milter is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# PyQuarantine-Milter is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with PyQuarantineMilter. If not, see <http://www.gnu.org/licenses/>.
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#
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__all__ = ["QuarantineMilter", "generate_milter_config", "reload_config", "mailer", "notifications", "run", "quarantines", "whitelists"]
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import ConfigParser
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import Milter
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import StringIO
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import logging
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import os
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import re
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import sys
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import mailer
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import quarantines
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import notifications
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import whitelists
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from Milter.utils import parse_addr
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from itertools import groupby
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class QuarantineMilter(Milter.Base):
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"""QuarantineMilter based on Milter.Base to implement milter communication
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The class variable config needs to be filled with the result of the generate_milter_config function.
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"""
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config = None
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global_config = None
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# list of default config files
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_config_files = ["/etc/pyquarantine/pyquarantine.conf", os.path.expanduser('~/pyquarantine.conf'), "pyquarantine.conf"]
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# list of possible actions
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_actions = {"ACCEPT": Milter.ACCEPT, "REJECT": Milter.REJECT, "DISCARD": Milter.DISCARD}
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def __init__(self):
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self.logger = logging.getLogger(__name__)
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# save config, it must not change during runtime
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self.global_config = QuarantineMilter.global_config
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self.config = QuarantineMilter.config
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def _get_preferred_quarantine(self):
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matching_quarantines = [q for q in self.recipients_quarantines.values() if q]
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if self.global_config["preferred_quarantine_action"] == "first":
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quarantine = sorted(matching_quarantines, key=lambda x: x["index"])[0]
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else:
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quarantine = sorted(matching_quarantines, key=lambda x: x["index"], reverse=True)[0]
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return quarantine
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@staticmethod
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def get_configfiles():
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return QuarantineMilter._config_files
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@staticmethod
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def get_actions():
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return QuarantineMilter._actions
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@staticmethod
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def set_configfiles(config_files):
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QuarantineMilter._config_files = config_files
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@Milter.noreply
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def envfrom(self, mailfrom, *str):
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self.mailfrom = "@".join(parse_addr(mailfrom)).lower()
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self.recipients = set()
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return Milter.CONTINUE
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@Milter.noreply
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def envrcpt(self, to, *str):
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self.recipients.add("@".join(parse_addr(to)).lower())
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return Milter.CONTINUE
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@Milter.noreply
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def data(self):
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self.queueid = self.getsymval('i')
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self.logger.debug("{}: received queue-id from MTA".format(self.queueid))
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self.recipients = list(self.recipients)
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self.headers = []
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self.subject = ""
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return Milter.CONTINUE
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@Milter.noreply
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def header(self, name, value):
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self.headers.append("{}: {}".format(name, value))
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if name.lower() == "subject":
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self.subject = value
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return Milter.CONTINUE
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def eoh(self):
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try:
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self.whitelist_cache = whitelists.WhitelistCache()
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# initialize a dict to set quaranines per recipient
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self.recipients_quarantines = {}
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# iterate email headers
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recipients_to_check = self.recipients.copy()
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for header in self.headers:
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self.logger.debug("{}: checking header against configured quarantines: {}".format(self.queueid, header))
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# iterate quarantines
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for quarantine in self.config:
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if len(self.recipients_quarantines) == len(self.recipients):
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# every recipient matched a quarantine already
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if max([q["index"] for q in self.recipients_quarantines.values()]) <= quarantine["index"]:
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# every recipient matched a quarantine with at least the same precedence already, skip checks against quarantines with lower precedence
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self.logger.debug("{}: {}: skip further checks of this header".format(self.queueid, quarantine["name"]))
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break
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# check email header against quarantine regex
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self.logger.debug("{}: {}: checking header against regex '{}'".format(self.queueid, quarantine["name"], quarantine["regex"]))
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if quarantine["regex_compiled"].match(header):
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self.logger.debug("{}: {}: header matched regex".format(self.queueid, quarantine["name"]))
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# check for whitelisted recipients
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whitelist = quarantine["whitelist_obj"]
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if whitelist != None:
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try:
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whitelisted_recipients = self.whitelist_cache.get_whitelisted_recipients(whitelist, self.mailfrom, recipients_to_check)
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except RuntimeError as e:
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self.logger.error("{}: {}: unable to query whitelist: {}".format(self.queueid, quarantine["name"], e))
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return Milter.TEMPFAIL
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else:
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whitelisted_recipients = {}
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# iterate recipients
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for recipient in recipients_to_check.copy():
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if recipient in whitelisted_recipients:
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# recipient is whitelisted in this quarantine
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self.logger.debug("{}: {}: recipient '{}' is whitelisted".format(self.queueid, quarantine["name"], recipient))
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continue
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if recipient not in self.recipients_quarantines.keys() or self.recipients_quarantines[recipient]["index"] > quarantine["index"]:
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self.logger.debug("{}: {}: set quarantine for recipient '{}'".format(self.queueid, quarantine["name"], recipient))
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self.recipients_quarantines[recipient] = quarantine
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if quarantine["index"] == 0:
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# we do not need to check recipients which matched the quarantine with the highest precedence already
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recipients_to_check.remove(recipient)
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else:
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self.logger.debug("{}: {}: a quarantine with the same or higher precedence matched already for recipient '{}'".format(self.queueid, quarantine["name"], recipient))
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if not recipients_to_check:
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self.logger.debug("{}: all recipients matched the first quarantine, skipping all remaining header checks".format(self.queueid))
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break
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# check if no quarantine has matched for all recipients
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if not self.recipients_quarantines:
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# accept email
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self.logger.info("{}: passed clean for all recipients".format(self.queueid))
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return Milter.ACCEPT
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# check if the email body is needed
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keep_body = False
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for recipient, quarantine in self.recipients_quarantines.items():
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if quarantine["quarantine_obj"] or quarantine["notification_obj"]:
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keep_body = True
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break
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if keep_body:
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self.logger.debug("{}: initializing memory buffer to save email data".format(self.queueid))
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# initialize memory buffer to save email data
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self.fp = StringIO.StringIO()
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# write email headers to memory buffer
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self.fp.write("{}\n".format("\n".join(self.headers)))
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else:
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# quarantine and notification are disabled on all matching quarantines, return configured action
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quarantine = self._get_preferred_quarantine()
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self.logger.info("{}: {} matching quarantine is '{}', performing milter action {}".format(self.queueid, self.global_config["preferred_quarantine_action"],
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quarantine["name"], quarantine["action"].upper()))
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return quarantine["milter_action"]
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return Milter.CONTINUE
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except Exception as e:
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self.logger.exception("an exception occured in eoh function: {}".format(e))
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return Milter.TEMPFAIL
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def body(self, chunk):
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try:
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# save received body chunk
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self.fp.write(chunk)
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except Exception as e:
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self.logger.exception("an exception occured in body function: {}".format(e))
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return Milter.TEMPFAIL
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return Milter.CONTINUE
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def eom(self):
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try:
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# processing recipients grouped by quarantines
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quarantines = []
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keyfunc = lambda x: self.recipients_quarantines[x]
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for quarantine, recipients in groupby(sorted(self.recipients_quarantines, key=keyfunc), keyfunc):
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quarantines.append((quarantine, list(recipients)))
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# iterate quarantines sorted by index
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for quarantine, recipients in sorted(quarantines, key=lambda x: x[0]["index"]):
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quarantine_id = ""
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# check if a quarantine is configured
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if quarantine["quarantine_obj"] != None:
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# add email to quarantine
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self.logger.info("{}: adding to quarantine '{}' for: {}".format(self.queueid, quarantine["name"], ", ".join(recipients)))
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try:
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quarantine_id = quarantine["quarantine_obj"].add(self.queueid, self.mailfrom, recipients, fp=self.fp)
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except RuntimeError as e:
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self.logger.error("{}: unable to add to quarantine '{}': {}".format(self.queueid, quarantine["name"], e))
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return Milter.TEMPFAIL
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# check if a notification is configured
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if quarantine["notification_obj"] != None:
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# notify
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self.logger.info("{}: sending notification for quarantine '{}' to: {}".format(self.queueid, quarantine["name"], ", ".join(recipients)))
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try:
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quarantine["notification_obj"].notify(self.queueid, quarantine_id, self.subject, self.mailfrom, recipients, fp=self.fp)
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except RuntimeError as e:
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self.logger.error("{}: unable to send notification for quarantine '{}': {}".format(self.queueid, quarantine["name"], e))
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return Milter.TEMPFAIL
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# remove processed recipient
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for recipient in recipients:
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self.delrcpt(recipient)
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self.recipients.remove(recipient)
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self.fp.close()
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# email passed clean for at least one recipient, accepting email
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if self.recipients:
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self.logger.info("{}: passed clean for: {}".format(self.queueid, ", ".join(self.recipients)))
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return Milter.ACCEPT
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## return configured action
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quarantine = self._get_preferred_quarantine()
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self.logger.info("{}: {} matching quarantine is '{}', performing milter action {}".format(self.queueid, self.global_config["preferred_quarantine_action"],
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quarantine["name"], quarantine["action"].upper()))
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return quarantine["milter_action"]
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except Exception as e:
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self.logger.exception("an exception occured in eom function: {}".format(e))
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return Milter.TEMPFAIL
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def generate_milter_config(configtest=False, config_files=[]):
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"Generate the configuration for QuarantineMilter class."
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logger = logging.getLogger(__name__)
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# read config file
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parser = ConfigParser.ConfigParser()
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if not config_files:
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config_files = parser.read(QuarantineMilter.get_configfiles())
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else:
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config_files = parser.read(config_files)
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if not config_files:
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raise RuntimeError("config file not found")
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QuarantineMilter.set_configfiles(config_files)
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os.chdir(os.path.dirname(config_files[0]))
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# check if mandatory config options in global section are present
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if "global" not in parser.sections():
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raise RuntimeError("mandatory section 'global' not present in config file")
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for option in ["quarantines", "preferred_quarantine_action"]:
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if not parser.has_option("global", option):
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raise RuntimeError("mandatory option '{}' not present in config section 'global'".format(option))
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# read global config section
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global_config = dict(parser.items("global"))
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global_config["preferred_quarantine_action"] = global_config["preferred_quarantine_action"].lower()
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if global_config["preferred_quarantine_action"] not in ["first", "last"]:
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raise RuntimeError("option preferred_quarantine_action has illegal value")
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# read active quarantine names
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quarantine_names = list(set(map(str.strip, global_config["quarantines"].split(","))))
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if "global" in quarantine_names:
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quarantine_names.remove("global")
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logger.warning("removed illegal quarantine name 'global' from list of active quarantines")
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if not quarantine_names:
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raise RuntimeError("no quarantines configured")
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milter_config = []
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logger.debug("preparing milter configuration ...")
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# iterate quarantine names
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for index, quarantine_name in enumerate(quarantine_names):
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# check if config section for current quarantine exists
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if quarantine_name not in parser.sections():
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raise RuntimeError("config section '{}' does not exist".format(quarantine_name))
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config = dict(parser.items(quarantine_name))
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# check if mandatory config options are present in config
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for option in ["regex", "quarantine_type", "notification_type", "action", "whitelist_type", "smtp_host", "smtp_port"]:
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if option not in config.keys() and \
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option in global_config.keys():
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config[option] = global_config[option]
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if option not in config.keys():
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raise RuntimeError("mandatory option '{}' not present in config section '{}' or 'global'".format(option, quarantine_name))
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# set quarantine name
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config["name"] = quarantine_name
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# set the index
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config["index"] = index
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# pre-compile regex
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logger.debug("{}: compiling regex '{}'".format(quarantine_name, config["regex"]))
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config["regex_compiled"] = re.compile(config["regex"])
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# create quarantine instance
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quarantine_type = config["quarantine_type"].lower()
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if quarantine_type in quarantines.TYPES.keys():
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logger.debug("{}: initializing quarantine type '{}'".format(quarantine_name, quarantine_type.upper()))
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quarantine = quarantines.TYPES[quarantine_type](global_config, config, configtest)
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elif quarantine_type == "none":
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logger.debug("{}: quarantine is NONE".format(quarantine_name))
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quarantine = None
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else:
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raise RuntimeError("{}: unknown quarantine type '{}'".format(quarantine_name, quarantine_type))
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config["quarantine_obj"] = quarantine
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# create whitelist instance
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whitelist_type = config["whitelist_type"].lower()
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if whitelist_type in whitelists.TYPES.keys():
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logger.debug("{}: initializing whitelist type '{}'".format(quarantine_name, whitelist_type.upper()))
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whitelist = whitelists.TYPES[whitelist_type](global_config, config, configtest)
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elif whitelist_type == "none":
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logger.debug("{}: whitelist is NONE".format(quarantine_name))
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whitelist = None
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else:
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raise RuntimeError("{}: unknown whitelist type '{}'".format(quarantine_name, whitelist_type))
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config["whitelist_obj"] = whitelist
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# create notification instance
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notification_type = config["notification_type"].lower()
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if notification_type in notifications.TYPES.keys():
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logger.debug("{}: initializing notification type '{}'".format(quarantine_name, notification_type.upper()))
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notification = notifications.TYPES[notification_type](global_config, config, configtest)
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elif notification_type == "none":
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logger.debug("{}: notification is NONE".format(quarantine_name))
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notification = None
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else:
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raise RuntimeError("{}: unknown notification type '{}'".format(quarantine_name, notification_type))
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config["notification_obj"] = notification
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# determining milter action for this quarantine
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action = config["action"].upper()
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if action in QuarantineMilter.get_actions().keys():
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logger.debug("{}: action is {}".format(quarantine_name, action))
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config["milter_action"] = QuarantineMilter.get_actions()[action]
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else:
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raise RuntimeError("{}: unknown action '{}'".format(quarantine_name, action))
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milter_config.append(config)
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return global_config, milter_config
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def reload_config():
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"Reload the configuration of QuarantineMilter class."
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logger = logging.getLogger(__name__)
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try:
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global_config, config = generate_milter_config()
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except RuntimeError as e:
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logger.info(e)
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logger.info("daemon is still running with previous configuration")
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else:
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logger.info("reloading configuration")
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QuarantineMilter.global_config = global_config
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QuarantineMilter.config = config
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