Base on Stretch, add Zeyple

data/Dockerfiles/postfix/Dockerfile

@@ -1,4 +1,4 @@
-FROM ubuntu:xenial
+FROM debian:testing-slim
 MAINTAINER Andre Peters <andre.peters@servercow.de>
 
 ENV DEBIAN_FRONTEND noninteractive
@@ -19,10 +19,19 @@ RUN apt-get install -y --no-install-recommends supervisor \
 	postfix-pcre \
 	syslog-ng \
 	syslog-ng-core \
-	ca-certificates
+	ca-certificates \
+	gnupg \
+	python-gpgme \
+	sudo \
+	dirmngr
 
+RUN addgroup --system --gid 600 zeyple
+RUN adduser --system --home /var/lib/zeyple --no-create-home --uid 600 --gid 600 --disabled-login zeyple
+RUN touch /var/log/zeyple.log && chown zeyple: /var/log/zeyple.log
 RUN sed -i -E 's/^(\s*)system\(\);/\1unix-stream("\/dev\/log");/' /etc/syslog-ng/syslog-ng.conf
 
+COPY zeyple.py /usr/local/bin/zeyple.py
+COPY zeyple.conf /etc/zeyple.conf
 COPY supervisord.conf /etc/supervisor/supervisord.conf
 COPY postfix.sh /opt/postfix.sh
 

data/Dockerfiles/postfix/postfix.sh

@@ -17,7 +17,7 @@ user = ${DBUSER}
 password = ${DBPASS}
 hosts = mysql
 dbname = ${DBNAME}
-query = SELECT IF( EXISTS( SELECT 'TLS_ACTIVE' FROM alias LEFT OUTER JOIN mailbox ON mailbox.username = alias.address WHERE (address='%s' OR address IN (SELECT CONCAT('%u', '@', target_domain) FROM alias_domain WHERE alias_domain='%d')) AND mailbox.tls_enforce_in = '1' AND mailbox.active = '1'), 'reject_plaintext_session', 'DUNNO') AS 'tls_enforce_in';
+query = SELECT IF( EXISTS( SELECT 'TLS_ACTIVE' FROM alias LEFT OUTER JOIN mailbox ON mailbox.username = alias.goto WHERE (address='%s' OR address IN (SELECT CONCAT('%u', '@', target_domain) FROM alias_domain WHERE alias_domain='%d')) AND mailbox.tls_enforce_in = '1' AND mailbox.active = '1'), 'reject_plaintext_session', NULL) AS 'tls_enforce_in';
 EOF
 
 cat <<EOF > /opt/postfix/conf/sql/mysql_tls_enforce_out_policy.cf
@@ -25,7 +25,7 @@ user = ${DBUSER}
 password = ${DBPASS}
 hosts = mysql
 dbname = ${DBNAME}
-query = SELECT IF( EXISTS( SELECT 'TLS_ACTIVE' FROM alias LEFT OUTER JOIN mailbox ON mailbox.username = alias.address WHERE (address='%s' OR address IN (SELECT CONCAT('%u', '@', target_domain) FROM alias_domain WHERE alias_domain='%d')) AND mailbox.tls_enforce_out = '1' AND mailbox.active = '1'), 'smtp_enforced_tls:', 'DUNNO') AS 'tls_enforce_out';
+query = SELECT IF( EXISTS( SELECT 'TLS_ACTIVE' FROM alias LEFT OUTER JOIN mailbox ON mailbox.username = alias.goto WHERE (address='%s' OR address IN (SELECT CONCAT('%u', '@', target_domain) FROM alias_domain WHERE alias_domain='%d')) AND mailbox.tls_enforce_out = '1' AND mailbox.active = '1'), 'smtp_enforced_tls:', NULL) AS 'tls_enforce_out';
 EOF
 
 cat <<EOF > /opt/postfix/conf/sql/mysql_virtual_alias_domain_catchall_maps.cf
@@ -92,11 +92,21 @@ dbname = ${DBNAME}
 query = SELECT goto FROM spamalias WHERE address='%s' AND validity >= UNIX_TIMESTAMP()
 EOF
 
+# Reset GPG key permissions
+mkdir -p /var/lib/zeyple/keys
+chmod 700 /var/lib/zeyple/keys
+chown -R 600:600 /var/lib/zeyple/keys
+
+# Fix Postfix permissions
+chgrp -R postdrop /var/spool/postfix/public
+chgrp -R postdrop /var/spool/postfix/maildrop
+postfix set-permissions
 postconf -c /opt/postfix/conf
 if [[ $? != 0 ]]; then
 	echo "Postfix configuration error, refusing to start."
 	exit 1
 else
 	postfix -c /opt/postfix/conf start
+	supervisorctl restart postfix-maillog
 	sleep 126144000
 fi

data/Dockerfiles/postfix/supervisord.conf

@@ -12,6 +12,17 @@ command=/opt/postfix.sh
 autorestart=true
 
 [program:postfix-maillog]
-command=/usr/bin/tail -f /var/log/mail.log
-stdout_logfile=/dev/fd/1
+command=/bin/tail -f /var/log/zeyple.log /var/log/mail.log
+stdout_logfile=/dev/stdout
 stdout_logfile_maxbytes=0
+
+[unix_http_server]
+file=/var/tmp/supervisord.sock  
+chmod=0770  
+chown=nobody:nogroup
+
+[supervisorctl]
+serverurl=unix:///var/tmp/supervisord.sock
+
+[rpcinterface:supervisor]
+supervisor.rpcinterface_factory = supervisor.rpcinterface:make_main_rpcinterface

data/Dockerfiles/postfix/zeyple.conf

@@ -0,0 +1,9 @@
+[zeyple]
+log_file = /var/log/zeyple.log
+
+[gpg]
+home = /var/lib/zeyple/keys
+
+[relay]
+host = localhost
+port = 10026

data/Dockerfiles/postfix/zeyple.py

@@ -0,0 +1,274 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import sys
+import os
+import logging
+import email
+import email.mime.multipart
+import email.mime.application
+import email.encoders
+import smtplib
+import copy
+from io import BytesIO
+
+try:
+    from configparser import SafeConfigParser  # Python 3
+except ImportError:
+    from ConfigParser import SafeConfigParser  # Python 2
+
+import gpgme
+
+# Boiler plate to avoid dependency on six
+# BBB: Python 2.7 support
+PY3K = sys.version_info > (3, 0)
+
+
+def message_from_binary(message):
+    if PY3K:
+        return email.message_from_bytes(message)
+    else:
+        return email.message_from_string(message)
+
+
+def as_binary_string(email):
+    if PY3K:
+        return email.as_bytes()
+    else:
+        return email.as_string()
+
+
+def encode_string(string):
+    if isinstance(string, bytes):
+        return string
+    else:
+        return string.encode('utf-8')
+
+
+__title__ = 'Zeyple'
+__version__ = '1.2.0'
+__author__ = 'Cédric Félizard'
+__license__ = 'AGPLv3+'
+__copyright__ = 'Copyright 2012-2016 Cédric Félizard'
+
+
+class Zeyple:
+    """Zeyple Encrypts Your Precious Log Emails"""
+
+    def __init__(self, config_fname='zeyple.conf'):
+        self.config = self.load_configuration(config_fname)
+
+        log_file = self.config.get('zeyple', 'log_file')
+        logging.basicConfig(
+            filename=log_file, level=logging.DEBUG,
+            format='%(asctime)s %(process)s %(levelname)s %(message)s'
+        )
+        logging.info("Zeyple ready to encrypt outgoing emails")
+
+    def load_configuration(self, filename):
+        """Reads and parses the config file"""
+
+        config = SafeConfigParser()
+        config.read([
+            os.path.join('/etc/', filename),
+            filename,
+        ])
+        if not config.sections():
+            raise IOError('Cannot open config file.')
+        return config
+
+    @property
+    def gpg(self):
+        protocol = gpgme.PROTOCOL_OpenPGP
+
+        if self.config.has_option('gpg', 'executable'):
+            executable = self.config.get('gpg', 'executable')
+        else:
+            executable = None  # Default value
+
+        home_dir = self.config.get('gpg', 'home')
+
+        ctx = gpgme.Context()
+        ctx.set_engine_info(protocol, executable, home_dir)
+        ctx.armor = True
+
+        return ctx
+
+    def process_message(self, message_data, recipients):
+        """Encrypts the message with recipient keys"""
+        message_data = encode_string(message_data)
+
+        in_message = message_from_binary(message_data)
+        logging.info(
+            "Processing outgoing message %s", in_message['Message-id'])
+
+        if not recipients:
+            logging.warn("Cannot find any recipients, ignoring")
+
+        sent_messages = []
+        for recipient in recipients:
+            logging.info("Recipient: %s", recipient)
+
+            key_id = self._user_key(recipient)
+            logging.info("Key ID: %s", key_id)
+
+            if key_id:
+                out_message = self._encrypt_message(in_message, key_id)
+
+                # Delete Content-Transfer-Encoding if present to default to
+                # "7bit" otherwise Thunderbird seems to hang in some cases.
+                del out_message["Content-Transfer-Encoding"]
+            else:
+                logging.warn("No keys found, message will be sent unencrypted")
+                out_message = copy.copy(in_message)
+
+            self._add_zeyple_header(out_message)
+            self._send_message(out_message, recipient)
+            sent_messages.append(out_message)
+
+        return sent_messages
+
+    def _get_version_part(self):
+        ret = email.mime.application.MIMEApplication(
+            'Version: 1\n',
+            'pgp-encrypted',
+            email.encoders.encode_noop,
+        )
+        ret.add_header(
+            'Content-Description',
+            "PGP/MIME version identification",
+        )
+        return ret
+
+    def _get_encrypted_part(self, payload):
+        ret = email.mime.application.MIMEApplication(
+            payload,
+            'octet-stream',
+            email.encoders.encode_noop,
+            name="encrypted.asc",
+        )
+        ret.add_header('Content-Description', "OpenPGP encrypted message")
+        ret.add_header(
+            'Content-Disposition',
+            'inline',
+            filename='encrypted.asc',
+        )
+        return ret
+
+    def _encrypt_message(self, in_message, key_id):
+        if in_message.is_multipart():
+            # get the body (after the first \n\n)
+            payload = in_message.as_string().split("\n\n", 1)[1].strip()
+
+            # prepend the Content-Type including the boundary
+            content_type = "Content-Type: " + in_message["Content-Type"]
+            payload = content_type + "\n\n" + payload
+
+            message = email.message.Message()
+            message.set_payload(payload)
+
+            payload = message.get_payload()
+
+        else:
+            payload = in_message.get_payload()
+            payload = encode_string(payload)
+
+            quoted_printable = email.charset.Charset('ascii')
+            quoted_printable.body_encoding = email.charset.QP
+
+            message = email.mime.nonmultipart.MIMENonMultipart(
+                'text', 'plain', charset='utf-8'
+            )
+            message.set_payload(payload, charset=quoted_printable)
+
+            mixed = email.mime.multipart.MIMEMultipart(
+                'mixed',
+                None,
+                [message],
+            )
+
+            # remove superfluous header
+            del mixed['MIME-Version']
+
+            payload = as_binary_string(mixed)
+
+        encrypted_payload = self._encrypt_payload(payload, [key_id])
+
+        version = self._get_version_part()
+        encrypted = self._get_encrypted_part(encrypted_payload)
+
+        out_message = copy.copy(in_message)
+        out_message.preamble = "This is an OpenPGP/MIME encrypted " \
+                               "message (RFC 4880 and 3156)"
+
+        if 'Content-Type' not in out_message:
+            out_message['Content-Type'] = 'multipart/encrypted'
+        else:
+            out_message.replace_header(
+                'Content-Type',
+                'multipart/encrypted',
+            )
+
+        out_message.set_param('protocol', 'application/pgp-encrypted')
+        out_message.set_payload([version, encrypted])
+
+        return out_message
+
+    def _encrypt_payload(self, payload, key_ids):
+        """Encrypts the payload with the given keys"""
+        payload = encode_string(payload)
+
+        plaintext = BytesIO(payload)
+        ciphertext = BytesIO()
+
+        self.gpg.armor = True
+
+        recipient = [self.gpg.get_key(key_id) for key_id in key_ids]
+
+        self.gpg.encrypt(recipient, gpgme.ENCRYPT_ALWAYS_TRUST,
+                         plaintext, ciphertext)
+
+        return ciphertext.getvalue()
+
+    def _user_key(self, email):
+        """Returns the GPG key for the given email address"""
+        logging.info("Trying to encrypt for %s", email)
+        keys = [key for key in self.gpg.keylist(email)]
+
+        if keys:
+            key = keys.pop()  # NOTE: looks like keys[0] is the master key
+            key_id = key.subkeys[0].keyid
+            return key_id
+
+        return None
+
+    def _add_zeyple_header(self, message):
+        if self.config.has_option('zeyple', 'add_header') and \
+           self.config.getboolean('zeyple', 'add_header'):
+            message.add_header(
+                'X-Zeyple',
+                "processed by {0} v{1}".format(__title__, __version__)
+            )
+
+    def _send_message(self, message, recipient):
+        """Sends the given message through the SMTP relay"""
+        logging.info("Sending message %s", message['Message-id'])
+
+        smtp = smtplib.SMTP(self.config.get('relay', 'host'),
+                            self.config.get('relay', 'port'))
+
+        smtp.sendmail(message['From'], recipient, message.as_string())
+        smtp.quit()
+
+        logging.info("Message %s sent", message['Message-id'])
+
+
+if __name__ == '__main__':
+    recipients = sys.argv[1:]
+
+    # BBB: Python 2.7 support
+    binary_stdin = sys.stdin.buffer if PY3K else sys.stdin
+    message = binary_stdin.read()
+
+    zeyple = Zeyple()
+    zeyple.process_message(message, recipients)