commit 75f820900246b1a58d5b647c8434947d036f7a3d Author: Thomas Oettli Date: Wed Sep 4 14:13:29 2019 +0200 Initial commit diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..0447b8b --- /dev/null +++ b/.gitignore @@ -0,0 +1,116 @@ +# Byte-compiled / optimized / DLL files +__pycache__/ +*.py[cod] +*$py.class + +# C extensions +*.so + +# Distribution / packaging +.Python +build/ +develop-eggs/ +dist/ +downloads/ +eggs/ +.eggs/ +lib/ +lib64/ +parts/ +sdist/ +var/ +wheels/ +pip-wheel-metadata/ +share/python-wheels/ +*.egg-info/ +.installed.cfg +*.egg +MANIFEST + +# PyInstaller +# Usually these files are written by a python script from a template +# before PyInstaller builds the exe, so as to inject date/other infos into it. +*.manifest +*.spec + +# Installer logs +pip-log.txt +pip-delete-this-directory.txt + +# Unit test / coverage reports +htmlcov/ +.tox/ +.nox/ +.coverage +.coverage.* +.cache +nosetests.xml +coverage.xml +*.cover +.hypothesis/ +.pytest_cache/ + +# Translations +*.mo +*.pot + +# Django stuff: +*.log +local_settings.py +db.sqlite3 + +# Flask stuff: +instance/ +.webassets-cache + +# Scrapy stuff: +.scrapy + +# Sphinx documentation +docs/_build/ + +# PyBuilder +target/ + +# Jupyter Notebook +.ipynb_checkpoints + +# IPython +profile_default/ +ipython_config.py + +# pyenv +.python-version + +# celery beat schedule file +celerybeat-schedule + +# SageMath parsed files +*.sage.py + +# Environments +.env +.venv +env/ +venv/ +ENV/ +env.bak/ +venv.bak/ + +# Spyder project settings +.spyderproject +.spyproject + +# Rope project settings +.ropeproject + +# mkdocs documentation +/site + +# mypy +.mypy_cache/ +.dmypy.json +dmypy.json + +# Pyre type checker +.pyre/ diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..f288702 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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It is safest +to attach them to the start of each source file to most effectively +state the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + + Copyright (C) + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + Copyright (C) + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/MANIFEST.in b/MANIFEST.in new file mode 100644 index 0000000..ca4758c --- /dev/null +++ b/MANIFEST.in @@ -0,0 +1,3 @@ +include LICENSE README.md +recursive-include docs * +recursive-include misc * diff --git a/README.md b/README.md new file mode 100644 index 0000000..bafe5cb --- /dev/null +++ b/README.md @@ -0,0 +1,51 @@ +# pyheader-milter +A pymilter based sendmail/postfix pre-queue filter with the ability to add, remove and modify e-mail headers. + +The project is currently in alpha status, but will soon be used in a productive enterprise environment and possibly existing bugs will be fixed. + +## Requirements +* pymilter +* netaddr + +## Configuration +The pyheader-milter uses an INI-style configuration file. The sections are described below. + +### Section "global" +Any available configuration option can be set in the global section as default instead of in a quarantine section. + +The following configuration options are mandatory in the global section: +* **rules** + Comma-separated, ordered list of active rules. For each, there must be a section of the same name in the configuration. + +### Rule sections +The following configuration options are mandatory for each rule: +* **action** + Set the action of this rule. Possible values are: + * **add** + * **del** + * **mod** +* **header** + Name of the header in case of adding a header, regular expression to match whole header lines in case of deleting or modifying a header. + +The following configuration options are mandatory for an add-rule: +* **value** + Value of the header. + +The following configuration options are mandatory for a mod-rule: +* **search** + Regular expression to match the value of header lines. You may use subgroups or named subgroups (python syntax) to include parts of the original value in the new value. +* **value** + New value of the header. + +The following configuration options are optional for each rule: +* **ignore_hosts** + Comma-separated list of host and network addresses. The rule will be skipped if the sending host is included here. +* **only_hosts** + Comma-separated list of host and network addresses. The rule will be skipped if the sending host is not included here. If a is included in both **ignore_hosts** and **only_hosts**, the rule will be skipped. +* **log** + Enable or disable logging of this rule. Possible values are: + * **true** + * **false** + +## Developer information +Everyone who wants to improve or extend this project is very welcome. diff --git a/docs/.pyheader-milter.conf.example.swp b/docs/.pyheader-milter.conf.example.swp new file mode 100644 index 0000000..2f1e865 Binary files /dev/null and b/docs/.pyheader-milter.conf.example.swp differ diff --git a/docs/pyheader-milter.conf.example b/docs/pyheader-milter.conf.example new file mode 100644 index 0000000..f19dd53 --- /dev/null +++ b/docs/pyheader-milter.conf.example @@ -0,0 +1,97 @@ +# This is an example /etc/pyheader-milter.conf file. +# Copy it into place before use. +# +# Comments: use '#' for comment lines and ';' (following a space) for inline comments. +# +# If an option is not present in a modification section, it will be read from +# the global section. +# + + +[global] + +# Option: rules +# Notes: Set active rules (comma-separated). +# Each rule must have a section with the same name below. +# The rule name 'global' is forbidden and will be ignored. +# Rule names must be unique. +# Values: [ ACTIVE ] +# +rules = add_header,del_header,mod_header + +# Option: ignore_hosts +# Notes: Set a list of host and network addresses to be ignored. +# All the common host/network notations are supported, including IPv6. +# Value: [ HOST ] +# +ignore_hosts = 127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 + +# Option: only_hosts +# Notes: Set a list of host and network addresses. +# All the common host/network notations are supported, including IPv6. +# Value: [ HOST ] +# +only_hosts = 127.0.0.0/8, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 + +# Option: log +# Notes: Set if modifications are logged. +# Value: [ true | false ] +# +log = true + + +[add_header] + +# Option: action +# Notes: Set the modification action. +# Values: [ add ] +action = add + +# Option: header +# Notes: Set the name of the header. +# Values: [ NAME ] +# +header = X-My-Own-Header + +# Option: value +# Notes: Set the value of the header. +# Values: [ VALUE ] +value = my own value + + +[del_header] + +# Option: action +# Notes: Set the modification action. +# Values: [ del ] +action = del + +# Option: header +# Notes: Set a regular expression to match the header lines to delete. +# Values: [ REGEX ] +# +header = ^Received:.* + + +[mod_header] + +# Option: action +# Notes: Set the modification action. +# Values: [ mod ] +action = mod + +# Option: header +# Notes: Set a regular expression to match the header lines to modify. +# Values: [ REGEX ] +# +header = ^Subject:.* + +# Option: search +# Notes: Set a regular expression to match the headers value. +# Values: [ VALUE ] +search = (?P.*) + +# Option: value +# Notes: Set the value of the header. +# Values: [ VALUE ] +value = [SPAM] \g diff --git a/misc/openrc/pyheader-milter.confd b/misc/openrc/pyheader-milter.confd new file mode 100644 index 0000000..b8a0c08 --- /dev/null +++ b/misc/openrc/pyheader-milter.confd @@ -0,0 +1,17 @@ +# /etc/conf.d/pyheader-milter: config file for /etc/init.d/pyheader-milter + +# Set the socket used to communicate with the MTA. +# Examples: +# unix:/path/to/socket a named pipe +# inet:8899 listen on ANY interface +# inet:8899@localhost listen on a specific interface +# inet6:8899 listen on ANY interface +# inet6:8899@[2001:db8:1234::1] listen on a specific interface +SOCKET="inet:8898@127.0.0.1" + +# Start the daemon as the user. You can optionally append a group name here also. +# USER="daemon" +# USER="daemon:nobody" + +# Optional parameters for pyheader-milter +# MILTER_OPTS="" diff --git a/misc/openrc/pyheader-milter.initd b/misc/openrc/pyheader-milter.initd new file mode 100755 index 0000000..8393089 --- /dev/null +++ b/misc/openrc/pyheader-milter.initd @@ -0,0 +1,50 @@ +#!/sbin/openrc-run + +user=${USER:-daemon} +socket="${SOCKET:-}" +milter_opts="${MILTER_OPTS:-}" + +pidfile="/run/${RC_SVCNAME}.pid" +command="/usr/bin/pyheader-milter" +command_args="-s ${socket} ${milter_opts}" +command_background=true +start_stop_daemon_args="--user ${user}" + +extra_commands="configtest" + +depend() { + need net + before mta +} + +checkconfig() { + if [ -z "${socket}" ]; then + eerror "No socket specified in config!" + fi + OUTPUT=$( ${command} ${command_args} -t 2>&1 ) + ret=$? + if [ $ret -ne 0 ]; then + eerror "${SVCNAME} has detected an error in your configuration:" + printf "%s\n" "${OUTPUT}" + fi + + return $ret +} + +configtest() { + ebegin "Checking ${SVCNAME} configuration" + checkconfig + eend $? +} + +start_pre() { + if [ "${RC_CMD}" != "restart" ]; then + checkconfig || return $? + fi +} + +stop_pre() { + if [ "${RC_CMD}" != "restart" ]; then + checkconfig || return $? + fi +} diff --git a/pyheadermilter/__init__.py b/pyheadermilter/__init__.py new file mode 100644 index 0000000..9777061 --- /dev/null +++ b/pyheadermilter/__init__.py @@ -0,0 +1,336 @@ +# PyHeader-Milter is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# PyHeader-Milter is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with PyHeader-Milter. If not, see . +# + +__all__ = ["HeaderRule", "HeaderMilter"] + +import Milter +import argparse +import configparser +import logging +import logging.handlers +import os +import re +import sys + +from Milter.utils import parse_addr +from netaddr import IPAddress, IPNetwork, AddrFormatError + + +class HeaderRule: + def __init__(self, name, action, header, search=None, value=None, ignore_hosts=[], only_hosts=[], log=True): + self.logger = logging.getLogger(__name__) + self.name = name + self._action = action + if action == "add": + self.header = header + else: + try: + self.header = re.compile(header, re.MULTILINE + re.DOTALL + re.IGNORECASE) + except re.error as e: + raise RuntimeError("unable to parse option 'header' of rule '{}': {}".format(name, e)) + if action == "mod": + try: + self.search = re.compile(search, re.MULTILINE + re.DOTALL + re.IGNORECASE) + except re.error as e: + raise RuntimeError("unable to parse option 'search' of rule '{}': {}".format(name, e)) + else: + self.search = search + self.value = value + self.ignore_hosts = [] + try: + for ignore in ignore_hosts: + self.ignore_hosts.append(IPNetwork(ignore)) + except AddrFormatError as e: + raise RuntimeError("unable to parse option 'ignore_hosts' of rule '{}': {}".format(name, e)) + self.only_hosts = [] + try: + for only in only_hosts: + self.only_hosts.append(IPNetwork(only)) + except AddrFormatError as e: + raise RuntimeError("unable to parse option 'only_hosts' of rule '{}': {}".format(name, e)) + self.log = log + + def get_action(self): + return self._action + + def log_modification(self): + return self.log + + def ignore_host(self, host): + ip = IPAddress(host) + ignore = False + for ignored in self.ignore_hosts: + if ip in ignored: + ignore = True + break + if not ignore and self.only_hosts: + ignore = True + for only in self.only_hosts: + if ip in only: + ignore = False + break + if ignore: + self.logger.debug("host {} is ignored by rule {}".format(host, self.name)) + return ignore + + def execute(self, headers): + modified = [] + if self._action == "add": + modified.append((self.header, self.value, 0, 1)) + else: + index = 0 + occurrences = {} + for name, value in headers: + if name not in occurrences.keys(): + occurrences[name] = 1 + else: + occurrences[name] += 1 + if self.header.search("{}: {}".format(name, value)): + if self._action == "del": + value = "" + else: + value = self.search.sub(self.value, value) + modified.append((name, value, index, occurrences[name])) + index += 1 + return modified + + +class HeaderMilter(Milter.Base): + """HeaderMilter based on Milter.Base to implement milter communication""" + + _rules = [] + + @staticmethod + def set_rules(rules): + HeaderMilter._rules = rules + + def __init__(self): + self.logger = logging.getLogger(__name__) + # save rules, it must not change during runtime + self.rules = HeaderMilter._rules.copy() + + def connect(self, IPname, family, hostaddr): + self.logger.debug("accepted milter connection from {} port {}".format(*hostaddr)) + ip = IPAddress(hostaddr[0]) + for rule in self.rules.copy(): + if rule.ignore_host(ip): + self.rules.remove(rule) + if not self.rules: + self.logger.debug("host {} is ignored by all rules, skip further processing".format(hostaddr[0])) + return Milter.ACCEPT + return Milter.CONTINUE + + @Milter.noreply + def data(self): + self.queueid = self.getsymval('i') + self.logger.debug("{}: received queue-id from MTA".format(self.queueid)) + self.headers = [] + return Milter.CONTINUE + + @Milter.noreply + def header(self, name, value): + self.headers.append((name, value)) + return Milter.CONTINUE + + def eom(self): + try: + for rule in self.rules: + action = rule.get_action() + log = rule.log_modification() + self.logger.debug("{}: executing rule '{}'".format(self.queueid, rule.name)) + modified = rule.execute(self.headers) + for name, value, index, occurrence in modified: + if action == "add": + if log: + self.logger.info("{}: add: header: {}".format(self.queueid, "{}: {}".format(name, value)[0:50])) + else: + self.logger.debug("{}: add: header: {}".format(self.queueid, "{}: {}".format(name, value)[0:50])) + self.headers.insert(0, (name, value)) + self.addheader(name, value, 1) + else: + self.chgheader(name, occurrence, value) + if action == "mod": + if log: + self.logger.info("{}: modify: header: {}".format(self.queueid, "{}: {}".format(name, self.headers[index][1])[0:50])) + else: + self.logger.debug("{}: modify: header (occ. {}): {}".format(self.queueid, occurrence, "{}: {}".format(name, self.headers[index][1])[0:50])) + self.headers[index] = (name, value) + elif action == "del": + if log: + self.logger.info("{}: delete: header: {}".format(self.queueid, "{}: {}".format(name, self.headers[index][1])[0:50])) + else: + self.logger.debug("{}: delete: header (occ. {}): {}".format(self.queueid, occurrence, "{}: {}".format(name, self.headers[index][1])[0:50])) + del self.headers[index] + return Milter.ACCEPT + except Exception as e: + self.logger.exception("an exception occured in eom function: {}".format(e)) + return Milter.TEMPFAIL + + +def main(): + "Run PyHeader-Milter." + # parse command line + parser = argparse.ArgumentParser(description="PyHeader milter daemon", + formatter_class=lambda prog: argparse.HelpFormatter(prog, max_help_position=45, width=140)) + parser.add_argument("-c", "--config", help="Config file to read.", default="/etc/pyheader-milter.conf") + parser.add_argument("-s", "--socket", help="Socket used to communicate with the MTA.", required=True) + parser.add_argument("-d", "--debug", help="Log debugging messages.", action="store_true") + parser.add_argument("-t", "--test", help="Check configuration.", action="store_true") + args = parser.parse_args() + + # setup logging + loglevel = logging.INFO + logname = "pyheader-milter" + syslog_name = logname + if args.debug: + loglevel = logging.DEBUG + logname = "{}[%(name)s]".format(logname) + syslog_name = "{}: [%(name)s] %(levelname)s".format(syslog_name) + + # set config files for milter class + root_logger = logging.getLogger() + root_logger.setLevel(loglevel) + + # setup console log + stdouthandler = logging.StreamHandler(sys.stdout) + stdouthandler.setLevel(logging.DEBUG) + formatter = logging.Formatter("%(message)s".format(logname)) + stdouthandler.setFormatter(formatter) + root_logger.addHandler(stdouthandler) + logger = logging.getLogger(__name__) + + try: + # read config file + parser = configparser.ConfigParser() + if not parser.read(args.config): + raise RuntimeError("config file not found") + + # check if mandatory config options in global section are present + if "global" not in parser.sections(): + raise RuntimeError("mandatory section 'global' not present in config file") + for option in ["rules"]: + if not parser.has_option("global", option): + raise RuntimeError("mandatory option '{}' not present in config section 'global'".format(option)) + + # read global config section + global_config = dict(parser.items("global")) + + # read active rules + active_rules = [ r.strip() for r in global_config["rules"].split(",") ] + if len(active_rules) != len(set(active_rules)): + raise RuntimeError("at least one rule is specified multiple times in 'rules' option") + if "global" in active_rules: + active_rules.remove("global") + logger.warning("removed illegal rule name 'global' from list of active rules") + if not active_rules: + raise RuntimeError("no rules configured") + + logger.debug("preparing milter configuration ...") + rules = [] + # iterate active rules + for rule_name in active_rules: + # check if config section exists + if rule_name not in parser.sections(): + raise RuntimeError("config section '{}' does not exist".format(rule_name)) + config = dict(parser.items(rule_name)) + + # check if mandatory option action is present in config + option = "action" + if option not in config.keys() and \ + option in global_config.keys(): + config[option] = global_config[option] + if option not in config.keys(): + raise RuntimeError("mandatory option '{}' not specified for rule '{}'".format(option, rule_name)) + config["action"] = config["action"].lower() + if config["action"] not in ["add", "del", "mod"]: + raise RuntimeError("invalid action specified for rule '{}'".format(rule_name)) + + # check if mandatory options are present in config + mandatory = ["header"] + if config["action"] == "add": + mandatory += ["value"] + elif config["action"] == "mod": + mandatory += ["search", "value"] + for option in mandatory: + if option not in config.keys() and \ + option in global_config.keys(): + config[option] = global_config[option] + if option not in config.keys(): + raise RuntimeError("mandatory option '{}' not specified for rule '{}'".format(option, rule_name)) + + # check if optional config options are present in config + defaults = { + "ignore_hosts": [], + "only_hosts": [], + "log": "true" + } + for option in defaults.keys(): + if option not in config.keys() and \ + option in global_config.keys(): + config[option] = global_config[option] + if option not in config.keys(): + config[option] = defaults[option] + if config["ignore_hosts"]: + config["ignore_hosts"] = [ h.strip() for h in config["ignore_hosts"].split(",") ] + if config["only_hosts"]: + config["only_hosts"] = [ h.strip() for h in config["only_hosts"].split(",") ] + config["log"] = config["log"].lower() + if config["log"] == "true": + config["log"] = True + elif config["log"] == "false": + config["log"] = False + else: + raise RuntimeError("invalid value specified for option 'log' for rule '{}'".format(rule_name)) + # add rule + logging.debug("adding rule '{}'".format(rule_name)) + rules.append(HeaderRule(name=rule_name, **config)) + + except RuntimeError as e: + logger.error(e) + sys.exit(255) + + if args.test: + print("Configuration ok") + sys.exit(0) + + # change log format for runtime + formatter = logging.Formatter("%(asctime)s {}: [%(levelname)s] %(message)s".format(logname), datefmt="%Y-%m-%d %H:%M:%S") + stdouthandler.setFormatter(formatter) + + # setup syslog + sysloghandler = logging.handlers.SysLogHandler(address="/dev/log", facility=logging.handlers.SysLogHandler.LOG_MAIL) + sysloghandler.setLevel(loglevel) + formatter = logging.Formatter("{}: %(message)s".format(syslog_name)) + sysloghandler.setFormatter(formatter) + root_logger.addHandler(sysloghandler) + + logger.info("PyHeader-Milter starting") + HeaderMilter.set_rules(rules) + + # register milter factory class + Milter.factory = HeaderMilter + Milter.set_exception_policy(Milter.TEMPFAIL) + + rc = 0 + try: + Milter.runmilter("pyheader-milter", socketname=args.socket, timeout=30) + except Milter.milter.error as e: + logger.error(e) + rc = 255 + logger.info("PyHeader-Milter terminated") + sys.exit(rc) + + +if __name__ == "__main__": + main() diff --git a/setup.py b/setup.py new file mode 100644 index 0000000..c63f4ae --- /dev/null +++ b/setup.py @@ -0,0 +1,35 @@ +from setuptools import setup + +def read_file(fname): + with open(fname, 'r') as f: + return f.read() + +setup(name = "pyheadermilter", + version = "0.0.1", + author = "Thomas Oettli", + author_email = "spacefreak@noop.ch", + description = "A pymilter based sendmail/postfix pre-queue filter.", + license = "GPL 3", + keywords = "header milter", + url = "https://github.com/spacefreak86/pyheader-milter", + packages = ["pyheadermilter"], + long_description = read_file("README.md"), + classifiers = [ + # 3 - Alpha + # 4 - Beta + # 5 - Production/Stable + "Development Status :: 3 - Alpha", + "License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)", + "Operating System :: OS Independent", + "Programming Language :: Python", + "Programming Language :: Python :: 3", + "Topic :: Communications :: Email :: Header" + ], + entry_points = { + "console_scripts": [ + "pyheader-milter=pyheadermilter:main" + ] + }, + install_requires = ["pymilter"], + python_requires = ">=3" +)