/usr/share/pyshared/bley.py is in bley 0.1.5-1build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 | # Copyright (c) 2009 Evgeni Golov <evgeni.golov@uni-duesseldorf.de>
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
# 3. Neither the name of the University nor the names of its contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
from twisted.internet.protocol import Factory
from twisted.names import client
from twisted.internet import defer
from twisted.internet import reactor
import datetime
from bleyhelpers import *
from postfix import PostfixPolicy
from time import sleep
class BleyPolicy(PostfixPolicy):
'''Implementation of intelligent greylisting based on `PostfixPolicy`'''
db = None
dbc = None
@defer.inlineCallbacks
def check_policy (self):
'''Check the incoming mail based on our policy and tell Postfix
about our decision.
The policy works as follows:
1. Accept if recipient=(postmaster|abuse)
2. Check local DB for an existing entry
3. When not found, check
1. DNSWLs (accept if found)
2. DNSBLs (reject if found)
3. HELO/dyn_host/sender_eq_recipient (reject if over threshold)
4. SPF (reject if over threshold)
5. Accept if not yet rejected
4. When found
1. Whitelisted: accept
2. Greylisted and waited: accept
3. Greylisted and not waited: reject
@type postfix_params: dict
@param postfix_params: parameters we got from Postfix
'''
if not self.db:
self.db = self.factory.settings.db
try:
self.dbc = self.db.cursor()
except:
self.safe_reconnect()
check_results = {'DNSWL': 0, 'DNSBL': 0, 'HELO': 0, 'DYN': 0, 'DB': -1, 'SPF': 0, 'S_EQ_R': 0 }
action = 'DUNNO'
postfix_params = self.params
# Strip everything after a + in the localpart, usefull for mailinglists etc
if postfix_params['sender'].find('+') != -1:
postfix_params['sender'] = postfix_params['sender'][:postfix_params['sender'].find('+')]+postfix_params['sender'][postfix_params['sender'].find('@'):]
if postfix_params['recipient'].find('+') != -1:
postfix_params['recipient'] = postfix_params['recipient'][:postfix_params['recipient'].find('+')]+postfix_params['recipient'][postfix_params['recipient'].find('@'):]
if postfix_params['client_address'] in self.factory.bad_cache.keys():
delta = datetime.datetime.now()-self.factory.bad_cache[postfix_params['client_address']]
if delta < datetime.timedelta(0,60,0):
action = 'DEFER_IF_PERMIT %s (cached result)' % self.factory.settings.reject_msg
if self.factory.settings.verbose:
self.factory.settings.logger('decided CACHED action=%s, checks: %s, postfix: %s\n' % (action, check_results, postfix_params))
else:
self.factory.settings.logger('decided CACHED action=%s, from=%s, to=%s\n' % (action, postfix_params['sender'], postfix_params['recipient']))
self.send_action(action)
return
else:
del self.factory.bad_cache[postfix_params['client_address']]
if postfix_params['client_address'] in self.factory.good_cache.keys():
delta = datetime.datetime.now()-self.factory.good_cache[postfix_params['client_address']]
if delta < datetime.timedelta(0,60,0):
action = 'DUNNO'
if self.factory.settings.verbose:
self.factory.settings.logger('decided CACHED action=%s, checks: %s, postfix: %s\n' % (action, check_results, postfix_params))
else:
self.factory.settings.logger('decided CACHED action=%s, from=%s, to=%s\n' % (action, postfix_params['sender'], postfix_params['recipient']))
self.send_action(action)
return
else:
del self.factory.good_cache[postfix_params['client_address']]
status = self.check_local_db(postfix_params)
# -1 : not found
# 0 : regular host, not in black, not in white, let it go
# 1 : regular host, but in white, let it go, dont check EHLO
# 2 : regular host, but in black, lets grey for now
if postfix_params['recipient'].lower().startswith('postmaster'):
action = 'DUNNO'
elif status == -1: # not found in local db...
check_results['DNSWL'] = yield self.check_dnswls(postfix_params['client_address'], self.factory.settings.dnswl_threshold)
if check_results['DNSWL'] >= self.factory.settings.dnswl_threshold:
new_status = 1
else:
check_results['DNSBL'] = yield self.check_dnsbls(postfix_params['client_address'], self.factory.settings.dnsbl_threshold)
check_results['HELO'] = check_helo(postfix_params)
check_results['DYN'] = check_dyn_host(postfix_params['client_name'])
# check_sender_eq_recipient:
if postfix_params['sender']==postfix_params['recipient']:
check_results['S_EQ_R'] = 1
if check_results['DNSBL'] < self.factory.settings.dnsbl_threshold and check_results['HELO']+check_results['DYN']+check_results['S_EQ_R'] < self.factory.settings.rfc_threshold:
check_results['SPF'] = check_spf(postfix_params)
else:
check_results['SPF'] = 0
if check_results['DNSBL'] >= self.factory.settings.dnsbl_threshold or check_results['HELO']+check_results['DYN']+check_results['SPF']+check_results['S_EQ_R'] >= self.factory.settings.rfc_threshold:
new_status = 2
action = 'DEFER_IF_PERMIT %s' % self.factory.settings.reject_msg
self.factory.bad_cache[postfix_params['client_address']] = datetime.datetime.now()
else:
new_status = 0
self.factory.good_cache[postfix_params['client_address']] = datetime.datetime.now()
query = "INSERT INTO bley_status (ip, status, last_action, sender, recipient) VALUES(%(client_address)s, %(new_status)s, NOW(), %(sender)s, %(recipient)s)"
postfix_params['new_status'] = new_status
try:
self.safe_execute(query, postfix_params)
except:
# the other thread already commited while we checked, ignore
pass
elif status[0] >= 2: # found to be greyed
check_results['DB'] = status[0]
delta = datetime.datetime.now()-status[1]
if delta > self.factory.settings.greylist_period+status[2]*self.factory.settings.greylist_penalty or delta > self.factory.settings.greylist_max:
action = 'DUNNO'
query = "UPDATE bley_status SET status=0, last_action=NOW() WHERE ip=%(client_address)s AND sender=%(sender)s AND recipient=%(recipient)s"
self.factory.good_cache[postfix_params['client_address']] = datetime.datetime.now()
else:
action = 'DEFER_IF_PERMIT %s' % self.factory.settings.reject_msg
query = "UPDATE bley_status SET fail_count=fail_count+1 WHERE ip=%(client_address)s AND sender=%(sender)s AND recipient=%(recipient)s"
self.factory.bad_cache[postfix_params['client_address']] = datetime.datetime.now()
self.safe_execute(query, postfix_params)
else: # found to be clean
check_results['DB'] = status[0]
action = 'DUNNO'
query = "UPDATE bley_status SET last_action=NOW() WHERE ip=%(client_address)s AND sender=%(sender)s AND recipient=%(recipient)s"
self.safe_execute(query, postfix_params)
self.factory.good_cache[postfix_params['client_address']] = datetime.datetime.now()
if self.factory.settings.verbose:
self.factory.settings.logger('decided action=%s, checks: %s, postfix: %s\n' % (action, check_results, postfix_params))
else:
self.factory.settings.logger('decided action=%s, from=%s, to=%s\n' % (action, postfix_params['sender'], postfix_params['recipient']))
self.send_action(action)
def check_local_db(self, postfix_params):
'''Check the sender for being in the local database.
Queries the local SQL database for the (ip,sender,recipient) tuple.
@type postfix_params: dict
@param postfix_params: parameters we got from Postfix
@rtype: list
@return: the result from SQL if any
'''
query = """SELECT status,last_action,fail_count,sender,recipient FROM bley_status
WHERE ip=%(client_address)s
AND sender=%(sender)s AND recipient=%(recipient)s
ORDER BY status ASC
LIMIT 1"""
try:
self.safe_execute(query, postfix_params)
result = self.dbc.fetchone()
except:
result = None
self.factory.settings.logger('check_local_db failed. sending unknown.\n')
if not result:
return -1
else:
return result
@defer.inlineCallbacks
def check_dnswls(self, ip, max):
'''Check the IP address in DNSWLs.
@type ip: string
@param ip: the IP to check
@type max: int
@param max: stop after max hits
@rtype: int
@return: in how many DNSWLs did we find ip?
'''
result = 0
for l in self.factory.settings.dnswls:
try:
d = yield self.check_dnsl(l, ip)
result += 1
except Exception:
pass
if result >= max:
break
defer.returnValue(result)
@defer.inlineCallbacks
def check_dnsbls(self, ip, max):
'''Check the IP address in DNSBLs.
@type ip: string
@param ip: the IP to check
@type max: int
@param max: stop after max hits
@rtype: int
@return: in how many DNSBLs did we find ip?
'''
result = 0
for l in self.factory.settings.dnsbls:
try:
d = yield self.check_dnsl(l, ip)
result += 1
except Exception:
pass
if result >= max:
break
defer.returnValue(result)
def check_dnsl(self, lst, ip):
'''Check the IP address in a DNS list.
@type ip: string
@param ip: the IP to check
@type lst: sting
@param lst: the DNS list to check in
@rtype: C{Deferred}
@return: twisted.names.client resolver
'''
rip = reverse_ip(ip)
lookup = '%s.%s' % (rip, lst)
d = client.lookupAddress(lookup)
return d
def safe_execute(self, query, params=None):
try:
self.dbc.execute(query, params)
self.db.commit()
except self.factory.settings.database.OperationalError:
self.safe_reconnect()
if self.db:
self.dbc.execute(query, params)
self.db.commit()
else:
self.factory.settings.logger('Could not reconnect to the database, exiting.\n')
reactor.stop()
def safe_reconnect(self):
self.factory.settings.logger('Reconnecting to the database after an error.\n')
try:
self.db.close()
except:
pass
self.db = None
retries = 0
while not self.db and retries < 30:
try:
self.factory.settings.db = self.db = self.factory.settings.database.connect(**self.factory.settings.dbsettings)
self.dbc = self.db.cursor()
except self.factory.settings.database.OperationalError:
self.db = None
retries += 1
sleep(1)
class BleyPolicyFactory(Factory):
protocol = BleyPolicy
def __init__(self, settings):
self.settings = settings
self.good_cache = {}
self.bad_cache = {}
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