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Viewing File: enforcetls.py

# -*- coding: UTF-8 -*-
#   Copyright 2012-2018 Fumail Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
#
#

from postomaat.shared import ScannerPlugin, DUNNO, strip_address, extract_domain, apply_template, FileList, \
    string_to_actioncode, get_default_cache
from postomaat.extensions.sql import SQL_EXTENSION_ENABLED, get_session, get_domain_setting
import os



class EnforceTLS(ScannerPlugin):
    
    def __init__(self,config,section=None):
        ScannerPlugin.__init__(self,config,section)
        self.logger=self._logger()
        
        self.selective_domain_loader = None
        
        self.requiredvars={
            'domainlist':{
                'default':'',
                'description':"""
                if this is empty, all recipient domains will be forced to use TLS
                txt:<filename> - get from simple textfile which lists one domain per line
                sql:<statement> - get from sql database :domain will be replaced with the actual domain name. must return field enforce_inbound_tls
                """,
            },
            'dbconnection':{
                'default':"mysql://root@localhost/enforcetls?charset=utf8",
                'description':'SQLAlchemy Connection string',
            },
            'action':{
                'default':'DEFER',
                'description':'Action if connection is not TLS encrypted. set to DUNNO, DEFER, REJECT',
            },
            'messagetemplate':{
                'default':'Unencrypted connection. This recipient requires TLS'
            }
        }



    def enforce_domain(self, to_domain):
        dbconnection = self.config.get(self.section,'dbconnection').strip()
        domainlist = self.config.get(self.section,'domainlist')
        enforce = False

        if domainlist.strip() == '':
            enforce = True

        elif domainlist.startswith('txt:'):
            domainfile = domainlist[4:]
            if self.selective_domain_loader is None:
                self.selective_domain_loader=FileList(domainfile,lowercase=True)
                if to_domain in self.selective_domain_loader.get_list():
                    enforce = True

        elif domainlist.startswith('sql:') and dbconnection != '':
            cache = get_default_cache()
            sqlquery = domainlist[4:]
            enforce = get_domain_setting(to_domain, dbconnection, sqlquery, cache, self.section, False, self.logger)

        return enforce

    
    
    def examine(self, suspect):
        encryption_protocol = suspect.get_value('encryption_protocol')
        recipient=suspect.get_value('recipient')
        
        rcpt_email = strip_address(recipient)
        if rcpt_email=='' or rcpt_email is None:
            return DUNNO

        enforce = self.enforce_domain(extract_domain(rcpt_email))

        action = DUNNO
        message = None
        if enforce and encryption_protocol == '':
            action=string_to_actioncode(self.config.get(self.section, 'action'))
            message = apply_template(self.config.get(self.section,'messagetemplate'),suspect)
            
        return action, message
    
    
    
    def lint(self):
        lint_ok = True
        if not self.checkConfig():
            print('Error checking config')
            lint_ok = False
            
        if lint_ok:
            domainlist = self.config.get(self.section,'domainlist')
            if domainlist.strip() == '':
                print('Enforcing TLS for all domains')
            elif domainlist.startswith('txt:'):
                domainfile = domainlist[4:]
                if not os.path.exists(domainfile):
                    print('Cannot find domain file %s' % domainfile)
                    lint_ok = False
            elif domainlist.startswith('sql:'):
                sqlquery = domainlist[4:]
                if not sqlquery.lower().startswith('select '):
                    lint_ok = False
                    print('SQL statement must be a SELECT query')
                if not SQL_EXTENSION_ENABLED:
                    print('SQLAlchemy not available, cannot use sql backend')
                if lint_ok:
                    dbconnection = self.config.get(self.section, 'dbconnection')
                    try:
                        conn=get_session(dbconnection)
                        conn.execute(sqlquery, {'domain':'example.com'})
                    except Exception as e:
                        lint_ok = False
                        print(str(e))
            else:
                lint_ok = False
                print('Could not determine domain list backend type')
        
        return lint_ok
    
    
    
    def __str__(self):
        return "EnforceTLS"