DandelionNStuff/pymilter
4
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
14d586901988ed3dacb34a8fb787580fded61178
pymilter/bms.py
T
Stuart Gathman 28ca3b2837 Expire and renew AddrCache entries
2005-12-28 20:17:29 +00:00

1735 lines
56 KiB
Python
Raw Blame History

#!/usr/bin/env python
# A simple milter that has grown quite a bit.
# $Log$
# Revision 1.45 2005/12/23 22:34:46 customdesigned
# Put guessed result in separate header.
#
# Revision 1.44 2005/12/23 21:47:07 customdesigned
# Move Received-SPF header to top.
#
# Revision 1.43 2005/12/09 16:54:01 customdesigned
# Select neutral DSN template for best_guess
#
# Revision 1.42 2005/12/01 22:42:32 customdesigned
# improve gossip support.
# Initialize srs_domain from srs.srs config property. Should probably
# always block unsigned DSN when signing all.
#
# Revision 1.41 2005/12/01 18:59:25 customdesigned
# Fix neutral policy. pobox.com -> openspf.org
#
# Revision 1.40 2005/11/07 21:22:35 customdesigned
# GOSSiP support, local database only.
#
# Revision 1.39 2005/10/31 00:04:58 customdesigned
# Simple implementation of trusted_forwarder list. Inefficient for
# more than 1 or 2 entries.
#
# Revision 1.38 2005/10/28 19:36:54 customdesigned
# Don't check internal_domains for trusted_relay.
#
# Revision 1.37 2005/10/28 09:30:49 customdesigned
# Do not send quarantine DSN when sender is DSN.
#
# Revision 1.36 2005/10/23 16:01:29 customdesigned
# Consider MAIL FROM a match for supply_sender when a subdomain of From or Sender
#
# Revision 1.35 2005/10/20 18:47:27 customdesigned
# Configure auto_whitelist senders.
#
# Revision 1.34 2005/10/19 21:07:49 customdesigned
# access.db stores keys in lower case
#
# Revision 1.33 2005/10/19 19:37:50 customdesigned
# Train screener on whitelisted messages.
#
# Revision 1.32 2005/10/14 16:17:31 customdesigned
# Auto whitelist refinements.
#
# Revision 1.31 2005/10/14 01:14:08 customdesigned
# Auto whitelist feature.
#
# Revision 1.30 2005/10/12 16:36:30 customdesigned
# Release 0.8.3
#
# Revision 1.29 2005/10/11 22:50:07 customdesigned
# Always check HELO except for SPF pass, temperror.
#
# Revision 1.28 2005/10/10 23:50:20 customdesigned
# Use logging module to make logging threadsafe (avoid splitting log lines)
#
# Revision 1.27 2005/10/10 20:15:33 customdesigned
# Configure SPF policy via sendmail access file.
#
# Revision 1.26 2005/10/07 03:23:40 customdesigned
# Banned users option. Experimental feature to supply Sender when
# missing and MFROM domain doesn't match From. Log cipher bits for
# SMTP AUTH. Sketch access file feature.
#
# Revision 1.25 2005/09/08 03:55:08 customdesigned
# Handle perverse MFROM quoting.
#
# Revision 1.24 2005/08/18 03:36:54 customdesigned
# Don't innoculate with SCREENED mail.
#
# Revision 1.23 2005/08/17 19:35:27 customdesigned
# Send DSN before adding message to quarantine.
#
# Revision 1.22 2005/08/11 22:17:58 customdesigned
# Consider SMTP AUTH connections internal.
#
# Revision 1.21 2005/08/04 21:21:31 customdesigned
# Treat fail like softfail for selected (braindead) domains.
# Treat mail according to extended processing results, but
# report any PermError that would officially result via DSN.
#
# Revision 1.20 2005/08/02 18:04:35 customdesigned
# Keep screened honeypot mail, but optionally discard honeypot only mail.
#
# Revision 1.19 2005/07/20 03:30:04 customdesigned
# Check pydspam version for honeypot, include latest pyspf changes.
#
# Revision 1.18 2005/07/17 01:25:44 customdesigned
# Log as well as use extended result for best guess.
#
# Revision 1.17 2005/07/15 20:25:36 customdesigned
# Use extended results processing for best_guess.
#
# Revision 1.16 2005/07/14 03:23:33 customdesigned
# Make SES package optional. Initial honeypot support.
#
# Revision 1.15 2005/07/06 04:05:40 customdesigned
# Initial SES integration.
#
# Revision 1.14 2005/07/02 23:27:31 customdesigned
# Don't match hostnames for internal connects.
#
# Revision 1.13 2005/07/01 16:30:24 customdesigned
# Always log trusted Received and Received-SPF headers.
#
# Revision 1.12 2005/06/20 22:35:35 customdesigned
# Setreply for rejectvirus.
#
# Revision 1.11 2005/06/17 02:07:20 customdesigned
# Release 0.8.1
#
# Revision 1.10 2005/06/16 18:35:51 customdesigned
# Ignore HeaderParseError decoding header
#
# Revision 1.9 2005/06/14 21:55:29 customdesigned
# Check internal_domains for outgoing mail.
#
# Revision 1.8 2005/06/06 18:24:59 customdesigned
# Properly log exceptions from pydspam
#
# Revision 1.7 2005/06/04 19:41:16 customdesigned
# Fix bugs from testing RPM
#
# Revision 1.6 2005/06/03 04:57:05 customdesigned
# Organize config reader by section. Create defang section.
#
# Revision 1.5 2005/06/02 15:00:17 customdesigned
# Configure banned extensions. Scan zipfile option with test case.
#
# Revision 1.4 2005/06/02 04:18:55 customdesigned
# Update copyright notices after reading article on /.
#
# Revision 1.3 2005/06/02 02:09:00 customdesigned
# Record timestamp in send_dsn.log
#
# Revision 1.2 2005/06/02 01:00:36 customdesigned
# Support configurable templates for DSNs.
#
#
# Revision 1.134 2005/05/25 15:36:43 stuart
# Use dynip module.
# Support smart aliasing of wiretap destination.
# Always send DSN for SOFTFAIL.
# Close forged bounce loophole when there are no headers.
#
# Revision 1.133 2005/03/16 21:58:04 stuart
# Auto DSN feature.
#
# Revision 1.132 2005/02/12 02:11:10 stuart
# Pass unit tests with python2.4.
#
# Revision 1.131 2005/02/11 18:34:13 stuart
# Handle garbage after quote in boundary.
#
# Revision 1.130 2005/02/10 01:10:58 stuart
# Fixed MimeMessage.ismodified()
#
# Revision 1.129 2005/02/10 00:56:48 stuart
# Runs with python2.4. Defang not working correctly - more work needed.
#
# Revision 1.128 2005/02/09 17:53:34 stuart
# Optionally run dspam on internal mail.
#
# Revision 1.127 2004/12/03 14:26:21 stuart
# Mark DYN PTR, REJECT softfail, log Received-SPF from trusted MTA.
#
# Revision 1.126 2004/11/24 14:39:38 stuart
# Also accept softfail if valid PTR or HELO.
#
# Revision 1.125 2004/11/19 16:40:14 stuart
# Block softfail except for listed domains.
#
# Revision 1.124 2004/11/19 06:18:04 stuart
# block softfail for configured domains only
#
# Revision 1.123 2004/11/18 20:36:49 stuart
# Recognize more dynamic hosts. Ignore dynamic PTR for best_guess.
#
# Revision 1.122 2004/11/18 17:16:10 stuart
# Recognize more dynamic ips.
#
# Revision 1.121 2004/11/09 22:37:48 stuart
# Don't accept helo names which are dynamic IP addresses.
#
# Revision 1.120 2004/11/09 20:33:50 stuart
# Recognize more dynamic PTR variations.
#
# Revision 1.118 2004/08/30 21:19:50 stuart
# Try best guess for HELO, expand setreply for common errors
#
# Revision 1.117 2004/08/23 02:27:53 stuart
# Allow multi rcpt CBV. Add some multiline replies.
#
# Revision 1.116 2004/08/20 22:27:52 stuart
# Generate TEMPFAIL for SPF softfail.
#
# Revision 1.115 2004/08/19 20:55:49 stuart
# Always show reversed SRS path.
# Check if encodings are an ASCII superset. Some messages were encoded as
# BIG5 and getting rejected even though chars were all in ascii subset.
#
# Revision 1.114 2004/07/27 00:40:12 stuart
# Make reject on no PTR optional.
#
# Revision 1.113 2004/07/23 23:11:14 stuart
# Log known malformed messages differently than general processing exceptions.
#
# Revision 1.112 2004/07/21 19:18:33 stuart
# Punt on UnicodeDecodeError when decoding headers.
# Accept a pass with default SPF for missing reverse IP.
#
# Revision 1.111 2004/07/18 13:13:31 stuart
# Reject invalid SRS only for SRS domain (which is the only one we
# know the key for).
# Reject senders that have neither reverse IP nor SPF.
#
# Revision 1.110 2004/06/12 03:13:18 stuart
# Block bounces only for SRS domain. Also treat mail from
# postmaster or mailer-daemon as DSN for SRS/SES checking purposes.
#
# Revision 1.109 2004/05/01 02:56:55 stuart
# Let multiple screeners share work.
#
# Revision 1.108 2004/04/29 20:36:23 stuart
# Require HELO name
#
# Revision 1.107 2004/04/24 22:55:29 stuart
# Move some files to make the RPM more standard.
#
# Revision 1.106 2004/04/21 18:29:08 stuart
# Validate hello name with SPF.
#
# Revision 1.105 2004/04/20 15:16:00 stuart
# Release 0.6.9
#
# Revision 1.104 2004/04/19 21:56:26 stuart
# Support SPF best_guess and get_header
#
# Revision 1.103 2004/04/10 02:31:01 stuart
# Fix timeout config
#
# Revision 1.102 2004/04/08 20:25:11 stuart
# Make libmilter timeout a config option
#
# Revision 1.101 2004/04/08 19:18:16 stuart
# Preserve case of local part in sender
#
# Revision 1.100 2004/04/08 18:41:15 stuart
# Reject numeric hello names
#
# Revision 1.99 2004/04/06 19:46:39 stuart
# Reject invalid SRS immediately for benefit of CallBack Verifiers.
#
# Revision 1.98 2004/04/06 15:28:20 stuart
# Release 0.6.8-2
#
# Revision 1.97 2004/04/06 13:07:43 stuart
# Pass original header name to check_header
#
# Revision 1.96 2004/04/06 03:27:03 stuart
# bugs from Redhat 9 testing
#
# Revision 1.95 2004/04/05 22:37:08 stuart
# Include Received-SPF headers in dspam.
#
# Revision 1.94 2004/04/05 22:16:50 stuart
# Separate check_header method taking decoded header.
# Reject multiple recipients for a bounce.
#
# Revision 1.93 2004/04/01 20:57:45 stuart
# Report only SRS like addresses as spoofed.
# Return TEMPFAIL on SPF error.
#
# Revision 1.92 2004/03/25 17:45:53 stuart
# Make spf_reject_neutral global in bms.py
#
# Revision 1.91 2004/03/25 03:38:02 stuart
# Reject neutral SPF result for selected domains.
#
# Revision 1.90 2004/03/25 03:27:33 stuart
# Support delegation of SPF records.
#
# Revision 1.89 2004/03/23 22:02:49 stuart
# Header decoding bug.
#
# Revision 1.88 2004/03/23 05:08:45 stuart
# Decode headers, indirect srs config.
#
# Revision 1.87 2004/03/18 02:21:16 stuart
# SRS checking
#
# Revision 1.86 2004/03/11 05:00:37 stuart
# Don't wipe out fail messages from SPF records.
# Hello blacklist
#
# Revision 1.85 2004/03/10 01:49:22 stuart
# Enhanced SPF support.
#
# Revision 1.84 2004/03/09 17:04:49 stuart
# Received-SPF header.
#
# Revision 1.83 2004/03/08 20:23:26 stuart
# SPF support
#
# Revision 1.82 2004/03/01 18:56:50 stuart
# Support progress reporting.
#
# Revision 1.81 2004/03/01 18:36:09 stuart
# Trusted relay.
#
# Revision 1.80 2004/01/12 21:10:58 stuart
# Support wildcard user for smart_alias
#
# Revision 1.79 2003/12/04 23:46:06 stuart
# Release 0.6.4
#
# Author: Stuart D. Gathman <stuart@bmsi.com>
# Copyright 2001,2002,2003,2004,2005 Business Management Systems, Inc.
# This code is under the GNU General Public License. See COPYING for details.
import sys
import os
import StringIO
import rfc822
import mime
import email.Errors
import Milter
import tempfile
import traceback
import ConfigParser
import time
import re
import anydbm
import Milter.dsn as dsn
from Milter.dynip import is_dynip as dynip
from fnmatch import fnmatchcase
from email.Header import decode_header
# Import gossip if available
try:
import gossip
from gossip.server import Gossip
except: gossip = None
# Import pysrs if available
try:
import SRS
srsre = re.compile(r'^SRS[01][+-=]',re.IGNORECASE)
except: SRS = None
try:
import SES
except: SES = None
# Import spf if available
try: import spf
except: spf = None
ip4re = re.compile(r'^[1-9][0-9]*\.[1-9][0-9]*\.[1-9][0-9]*\.[1-9][0-9]*$')
import logging
# Thanks to Chris Liechti for config parsing suggestions
# Global configuration defaults suitable for test framework.
socketname = "/tmp/pythonsock"
reject_virus_from = ()
wiretap_users = {}
discard_users = {}
wiretap_dest = None
blind_wiretap = True
check_user = {}
block_forward = {}
hide_path = ()
log_headers = False
block_chinese = False
spam_words = ()
porn_words = ()
banned_exts = mime.extlist.split(',')
scan_zip = False
scan_html = True
scan_rfc822 = True
internal_connect = ()
trusted_relay = ()
trusted_forwarder = ()
internal_domains = ()
banned_users = ()
hello_blacklist = ()
smart_alias = {}
dspam_dict = None
dspam_users = {}
dspam_userdir = None
dspam_exempt = {}
dspam_whitelist = {}
whitelist_senders = {}
dspam_screener = ()
dspam_internal = True # True if internal mail should be dspammed
dspam_reject = ()
dspam_sizelimit = 180000
srs = None
ses = None
srs_reject_spoofed = False
srs_domain = None
spf_reject_neutral = ()
spf_accept_softfail = ()
spf_accept_fail = ()
spf_best_guess = False
spf_reject_noptr = False
supply_sender = False
access_file = None
timeout = 600
logging.basicConfig(
stream=sys.stdout,
level=logging.INFO,
format='%(asctime)s %(message)s',
datefmt='%Y%b%d %H:%M:%S'
)
milter_log = logging.getLogger('milter')
if gossip:
gossip_node = Gossip('gossip4.db',120)
class MilterConfigParser(ConfigParser.ConfigParser):
def getlist(self,sect,opt):
if self.has_option(sect,opt):
return [q.strip() for q in self.get(sect,opt).split(',')]
return []
def getaddrset(self,sect,opt):
if not self.has_option(sect,opt):
return {}
s = self.get(sect,opt)
d = {}
for q in s.split(','):
q = q.strip()
if q.startswith('file:'):
domain = q[5:]
d[domain] = d.setdefault(domain,[]) + open(domain,'r').read().split()
else:
user,domain = q.split('@')
d.setdefault(domain,[]).append(user)
return d
def getaddrdict(self,sect,opt):
if not self.has_option(sect,opt):
return {}
d = {}
for q in self.get(sect,opt).split(','):
q = q.strip()
if self.has_option(sect,q):
l = self.get(sect,q)
for addr in l.split(','):
addr = addr.strip()
if addr.startswith('file:'):
fname = addr[5:]
for a in open(fname,'r').read().split():
d[a] = q
else:
d[addr] = q
return d
def getdefault(self,sect,opt,default=None):
if self.has_option(sect,opt):
return self.get(sect,opt)
return default
def read_config(list):
cp = MilterConfigParser({
'tempdir': "/var/log/milter/save",
'socket': "/var/run/milter/pythonsock",
'timeout': '600',
'scan_html': 'no',
'scan_rfc822': 'yes',
'scan_zip': 'no',
'block_chinese': 'no',
'log_headers': 'no',
'blind_wiretap': 'yes',
'maxage': '8',
'hashlength': '8',
'reject_spoofed': 'no',
'reject_noptr': 'no',
'supply_sender': 'no',
'best_guess': 'no',
'dspam_internal': 'yes'
})
cp.read(list)
# milter section
tempfile.tempdir = cp.get('milter','tempdir')
global socketname, timeout, check_user, log_headers
global internal_connect, internal_domains, trusted_relay, hello_blacklist
socketname = cp.get('milter','socket')
timeout = cp.getint('milter','timeout')
check_user = cp.getaddrset('milter','check_user')
log_headers = cp.getboolean('milter','log_headers')
internal_connect = cp.getlist('milter','internal_connect')
internal_domains = cp.getlist('milter','internal_domains')
trusted_relay = cp.getlist('milter','trusted_relay')
hello_blacklist = cp.getlist('milter','hello_blacklist')
# defang section
global scan_rfc822, scan_html, block_chinese, scan_zip, block_forward
global banned_exts, porn_words, spam_words
if cp.has_section('defang'):
section = 'defang'
# for backward compatibility,
# banned extensions defaults to empty only when defang section exists
banned_exts = cp.getlist(section,'banned_exts')
else: # use milter section if no defang section for compatibility
section = 'milter'
scan_rfc822 = cp.getboolean(section,'scan_rfc822')
scan_zip = cp.getboolean(section,'scan_zip')
scan_html = cp.getboolean(section,'scan_html')
block_chinese = cp.getboolean(section,'block_chinese')
block_forward = cp.getaddrset(section,'block_forward')
porn_words = cp.getlist(section,'porn_words')
spam_words = cp.getlist(section,'spam_words')
# scrub section
global hide_path, reject_virus_from
hide_path = cp.getlist('scrub','hide_path')
reject_virus_from = cp.getlist('scrub','reject_virus_from')
# wiretap section
global blind_wiretap, wiretap_users, wiretap_dest, discard_users
blind_wiretap = cp.getboolean('wiretap','blind')
wiretap_users = cp.getaddrset('wiretap','users')
discard_users = cp.getaddrset('wiretap','discard')
wiretap_dest = cp.getdefault('wiretap','dest')
if wiretap_dest: wiretap_dest = '<%s>' % wiretap_dest
global smart_alias
for sa in cp.getlist('wiretap','smart_alias'):
sm = cp.getlist('wiretap',sa)
if len(sm) < 2:
milter_log.warning('malformed smart alias: %s',sa)
continue
if len(sm) == 2: sm.append(sa)
key = (sm[0],sm[1])
smart_alias[key] = sm[2:]
# dspam section
global dspam_dict, dspam_users, dspam_userdir, dspam_exempt, dspam_internal
global dspam_screener,dspam_whitelist,dspam_reject,dspam_sizelimit
global whitelist_senders
whitelist_senders = cp.getaddrset('dspam','whitelist_senders')
dspam_dict = cp.getdefault('dspam','dspam_dict')
dspam_exempt = cp.getaddrset('dspam','dspam_exempt')
dspam_whitelist = cp.getaddrset('dspam','dspam_whitelist')
dspam_users = cp.getaddrdict('dspam','dspam_users')
dspam_userdir = cp.getdefault('dspam','dspam_userdir')
dspam_screener = cp.getlist('dspam','dspam_screener')
dspam_reject = cp.getlist('dspam','dspam_reject')
dspam_internal = cp.getboolean('dspam','dspam_internal')
if cp.has_option('dspam','dspam_sizelimit'):
dspam_sizelimit = cp.getint('dspam','dspam_sizelimit')
# spf section
global spf_reject_neutral,spf_best_guess,SRS,spf_reject_noptr
global spf_accept_softfail,spf_accept_fail,supply_sender,access_file
global trusted_forwarder
if spf:
spf.DELEGATE = cp.getdefault('spf','delegate')
spf_reject_neutral = cp.getlist('spf','reject_neutral')
spf_accept_softfail = cp.getlist('spf','accept_softfail')
spf_accept_fail = cp.getlist('spf','accept_fail')
spf_best_guess = cp.getboolean('spf','best_guess')
spf_reject_noptr = cp.getboolean('spf','reject_noptr')
supply_sender = cp.getboolean('spf','supply_sender')
access_file = cp.getdefault('spf','access_file')
trusted_forwarder = cp.getlist('spf','trusted_forwarder')
srs_config = cp.getdefault('srs','config')
if srs_config: cp.read([srs_config])
srs_secret = cp.getdefault('srs','secret')
if SRS and srs_secret:
global ses,srs,srs_reject_spoofed,srs_domain,banned_users
database = cp.getdefault('srs','database')
srs_reject_spoofed = cp.getboolean('srs','reject_spoofed')
maxage = cp.getint('srs','maxage')
hashlength = cp.getint('srs','hashlength')
separator = cp.getdefault('srs','separator','=')
if database:
import SRS.DB
srs = SRS.DB.DB(database=database,secret=srs_secret,
maxage=maxage,hashlength=hashlength,separator=separator)
else:
srs = SRS.Guarded.Guarded(secret=srs_secret,
maxage=maxage,hashlength=hashlength,separator=separator)
if SES:
ses = SES.new(secret=srs_secret,expiration=maxage)
srs_domain = cp.getlist('srs','ses')
else:
srs_domain = cp.getlist('srs','srs')
srs_domain.append(cp.getdefault('srs','fwdomain'))
banned_users = cp.getlist('srs','banned_users')
#print srs_domain
def parse_addr(t):
"""Split email into user,domain.
>>> parse_addr('user@example.com')
['user', 'example.com']
>>> parse_addr('"user@example.com"')
['user@example.com']
>>> parse_addr('"user@bar"@example.com')
['user@bar', 'example.com']
>>> parse_addr('foo')
['foo']
"""
if t.startswith('<') and t.endswith('>'): t = t[1:-1]
if t.startswith('"'):
if t.endswith('"'): return [t[1:-1]]
pos = t.find('"@')
if pos > 0: return [t[1:pos],t[pos+2:]]
return t.split('@')
def parse_header(val):
"""Decode headers gratuitously encoded to hide the content.
"""
try:
h = decode_header(val)
if not len(h) or (not h[0][1] and len(h) == 1): return val
u = []
for s,enc in h:
if enc:
try:
u.append(unicode(s,enc))
except LookupError:
u.append(unicode(s))
else:
u.append(unicode(s))
u = ''.join(u)
for enc in ('us-ascii','iso-8859-1','utf8'):
try:
return u.encode(enc)
except UnicodeError: continue
except UnicodeDecodeError: pass
except LookupError: pass
except email.Errors.HeaderParseError: pass
return val
class SPFPolicy(object):
"Get SPF policy by result, defaulting to classic policy from pymilter.cfg"
def __init__(self,domain):
self.domain = domain.lower()
if access_file:
try: acf = anydbm.open(access_file,'r')
except: acf = None
else: acf = None
self.acf = acf
def getPolicy(self,pfx):
acf = self.acf
if not acf: return None
try:
return acf[pfx + self.domain]
except KeyError:
try:
return acf[pfx]
except KeyError:
return None
def getFailPolicy(self):
policy = self.getPolicy('spf-fail:')
if not policy:
if self.domain in spf_accept_fail:
policy = 'CBV'
else:
policy = 'REJECT'
return policy
def getNonePolicy(self):
policy = self.getPolicy('spf-none:')
if not policy:
if spf_reject_noptr:
policy = 'REJECT'
else:
policy = 'CBV'
return policy
def getSoftfailPolicy(self):
policy = self.getPolicy('spf-softfail:')
if not policy:
if self.domain in spf_accept_softfail:
policy = 'OK'
elif self.domain in spf_reject_neutral:
policy = 'REJECT'
else:
policy = 'CBV'
return policy
def getNeutralPolicy(self):
policy = self.getPolicy('spf-neutral:')
if not policy:
if self.domain in spf_reject_neutral:
policy = 'REJECT'
policy = 'OK'
return policy
def getPermErrorPolicy(self):
policy = self.getPolicy('spf-permerror:')
if not policy:
policy = 'REJECT'
return policy
def getPassPolicy(self):
policy = self.getPolicy('spf-pass:')
if not policy:
policy = 'OK'
return policy
class AddrCache(object):
time_format = '%Y%b%d %H:%M:%S %Z'
def __init__(self,renew=7):
self.age = renew
def load(self,fname,age=0):
if not age:
age = self.age
self.fname = fname
cache = {}
self.cache = cache
now = time.time()
try:
too_old = now - age*24*60*60 # max age in days
for ln in open(self.fname):
try:
rcpt,ts = ln.strip().split(None,1)
l = time.strptime(ts,AddrCache.time_format)
t = time.mktime(l)
if t > too_old:
cache[rcpt.lower()] = (t,None)
except:
cache[ln.strip().lower()] = (now,None)
except IOError: pass
def has_key(self,sender):
try:
ts,res = self.cache[sender.lower()]
too_old = time.time() - self.age*24*60*60 # max age in days
if ts > too_old:
return True
del self.cache[sender.lower()]
except KeyError:
pass
return False
def __getitem__(self,sender):
ts,res = self.cache[sender.lower()]
too_old = time.time() - self.age*24*60*60 # max age in days
if ts > too_old:
return res
del self.cache[sender.lower()]
raise KeyError, sender
def __setitem__(self,sender,res):
lsender = sender.lower()
now = time.time()
cached = self.has_key(sender)
if not cached:
self.cache[lsender] = (now,res)
if not res:
s = time.strftime(AddrCache.time_format,time.localtime(now))
print >>open(self.fname,'a'),sender,s # log refreshed senders
def __len__(self):
return len(self.cache)
cbv_cache = AddrCache(renew=7)
cbv_cache.load('send_dsn.log',age=7)
auto_whitelist = AddrCache(renew=30)
auto_whitelist.load('auto_whitelist.log',age=120)
class bmsMilter(Milter.Milter):
"""Milter to replace attachments poisonous to Windows with a WARNING message,
check SPF, and other anti-forgery features, and implement wiretapping
and smart alias redirection."""
def log(self,*msg):
milter_log.info('[%d] %s',self.id,' '.join([str(m) for m in msg]))
def __init__(self):
self.tempname = None
self.mailfrom = None # sender in SMTP form
self.canon_from = None # sender in end user form
self.fp = None
self.bodysize = 0
self.id = Milter.uniqueID()
# delrcpt can only be called from eom(). This accumulates recipient
# changes which can then be applied by alter_recipients()
def del_recipient(self,rcpt):
rcpt = rcpt.lower()
if not rcpt in self.discard_list:
self.discard_list.append(rcpt)
# addrcpt can only be called from eom(). This accumulates recipient
# changes which can then be applied by alter_recipients()
def add_recipient(self,rcpt):
rcpt = rcpt.lower()
if not rcpt in self.redirect_list:
self.redirect_list.append(rcpt)
# addheader can only be called from eom(). This accumulates added headers
# which can then be applied by alter_headers()
def add_header(self,name,val,idx=-1):
self.new_headers.append((name,val,idx))
self.log('%s: %s' % (name,val))
def connect(self,hostname,unused,hostaddr):
self.internal_connection = False
self.trusted_relay = False
# sometimes people put extra space in sendmail config, so we strip
self.receiver = self.getsymval('j').strip()
if hostaddr and len(hostaddr) > 0:
ipaddr = hostaddr[0]
for pat in internal_connect:
if fnmatchcase(ipaddr,pat):
self.internal_connection = True
break
for pat in trusted_relay:
if fnmatchcase(ipaddr,pat):
self.trusted_relay = True
break
else: ipaddr = ''
self.connectip = ipaddr
self.missing_ptr = dynip(hostname,self.connectip)
if self.internal_connection:
connecttype = 'INTERNAL'
else:
connecttype = 'EXTERNAL'
if self.trusted_relay:
connecttype += ' TRUSTED'
if self.missing_ptr:
connecttype += ' DYN'
self.log("connect from %s at %s %s" % (hostname,hostaddr,connecttype))
self.hello_name = None
self.connecthost = hostname
if hostname == 'localhost' and not ipaddr.startswith('127.') \
or hostname == '.':
self.log("REJECT: PTR is",hostname)
self.setreply('550','5.7.1', '"%s" is not a reasonable PTR name'%hostname)
return Milter.REJECT
return Milter.CONTINUE
def hello(self,hostname):
self.hello_name = hostname
self.log("hello from %s" % hostname)
if ip4re.match(hostname):
self.log("REJECT: numeric hello name:",hostname)
self.setreply('550','5.7.1','hello name cannot be numeric ip')
return Milter.REJECT
if not self.internal_connection and hostname in hello_blacklist:
self.log("REJECT: spam from self:",hostname)
self.setreply('550','5.7.1','I hate talking to myself.')
return Milter.REJECT
return Milter.CONTINUE
def smart_alias(self,to):
if smart_alias:
t = parse_addr(to.lower())
if len(t) == 2:
ct = '@'.join(t)
else:
ct = t[0]
cf = self.canon_from
cf0 = cf.split('@',1)
if len(cf0) == 2:
cf0 = '@' + cf0[1]
else:
cf0 = cf
for key in ((cf,ct),(cf0,ct)):
if smart_alias.has_key(key):
self.del_recipient(to)
for t in smart_alias[key]:
self.add_recipient('<%s>'%t)
# multiple messages can be received on a single connection
# envfrom (MAIL FROM in the SMTP protocol) seems to mark the start
# of each message.
def envfrom(self,f,*str):
self.log("mail from",f,str)
self.fp = StringIO.StringIO()
self.tempname = None
self.mailfrom = f
self.forward = True
self.bodysize = 0
self.hidepath = False
self.discard = False
self.dspam = True
self.whitelist = False
self.reject_spam = True
self.data_allowed = True
self.trust_received = self.trusted_relay
self.trust_spf = self.trusted_relay
self.redirect_list = []
self.discard_list = []
self.new_headers = []
self.recipients = []
self.cbv_needed = None
self.whitelist_sender = False
t = parse_addr(f)
if len(t) == 2: t[1] = t[1].lower()
self.canon_from = '@'.join(t)
# Some braindead MTAs can't be relied upon to properly flag DSNs.
# This heuristic tries to recognize such.
self.is_bounce = (f == '<>' or t[0].lower() in banned_users
#and t[1] == self.hello_name
)
# Check SMTP AUTH, also available:
# auth_authen authenticated user
# auth_author (ESMTP AUTH= param)
# auth_ssf (connection security, 0 = unencrypted)
# auth_type (authentication method, CRAM-MD5, DIGEST-MD5, PLAIN, etc)
# cipher_bits SSL encryption strength
# cert_subject SSL cert subject
# verify SSL cert verified
self.user = self.getsymval('{auth_authen}')
if self.user:
# Very simple SMTP AUTH policy by defaul:
# any successful authentication is considered INTERNAL
# FIXME: configure allowed MAIL FROM by user
self.internal_connection = True
self.log(
"SMTP AUTH:",self.user, self.getsymval('{auth_type}'),
"sslbits =",self.getsymval('{cipher_bits}'),
"ssf =",self.getsymval('{auth_ssf}'), "INTERNAL"
)
if self.getsymval('{verify}'):
self.log("SSL AUTH:",
self.getsymval('{cert_subject}'),
"verify =",self.getsymval('{verify}')
)
self.fp.write('From %s %s\n' % (self.canon_from,time.ctime()))
if len(t) == 2:
user,domain = t
if not self.internal_connection:
if not self.trusted_relay:
for pat in internal_domains:
if fnmatchcase(domain,pat):
self.log("REJECT: spam from self",pat)
self.setreply('550','5.7.1','I hate talking to myself.')
return Milter.REJECT
else:
if internal_domains:
for pat in internal_domains:
if fnmatchcase(domain,pat): break
else:
self.log("REJECT: zombie PC at ",self.connectip,
" sending MAIL FROM ",self.canon_from)
self.setreply('550','5.7.1',
'Your PC is using an unauthorized MAIL FROM.',
'It is either badly misconfigured or controlled by organized crime.'
)
return Milter.REJECT
wl_users = whitelist_senders.get(domain,())
if user in wl_users or '' in wl_users:
self.whitelist_sender = True
self.rejectvirus = domain in reject_virus_from
if user in wiretap_users.get(domain,()):
self.add_recipient(wiretap_dest)
self.smart_alias(wiretap_dest)
if user in discard_users.get(domain,()):
self.discard = True
exempt_users = dspam_whitelist.get(domain,())
if user in exempt_users or '' in exempt_users:
self.dspam = False
else:
self.rejectvirus = False
domain = None
if not self.hello_name:
self.log("REJECT: missing HELO")
self.setreply('550','5.7.1',"It's polite to say HELO first.")
return Milter.REJECT
self.umis = None
if not (self.internal_connection or self.trusted_relay) \
and self.connectip and spf:
return self.check_spf()
else:
self.spf = None
return Milter.CONTINUE
def check_spf(self):
receiver = self.receiver
for tf in trusted_forwarder:
q = spf.query(self.connectip,'',tf,receiver=receiver,strict=False)
res,code,txt = q.check()
if res == 'pass':
self.log("TRUSTED_FORWARDER:",tf)
break
else:
q = spf.query(self.connectip,self.canon_from,self.hello_name,
receiver=receiver,strict=False)
q.set_default_explanation(
'SPF fail: see http://openspf.org/why.html?sender=%s&ip=%s' % (q.s,q.i))
res,code,txt = q.check()
q.result = res
if res in ('unknown','permerror') and q.perm_error and q.perm_error.ext:
self.cbv_needed = q # report SPF syntax error to sender
res,code,txt = q.perm_error.ext # extended (lax processing) result
txt = 'EXT: ' + txt
p = SPFPolicy(q.o)
if res not in ('pass','error','temperror'):
if self.mailfrom != '<>':
# check hello name via spf unless spf pass
h = spf.query(self.connectip,'',self.hello_name,receiver=receiver)
hres,hcode,htxt = h.check()
if hres in ('deny','fail','neutral','softfail'):
self.log('REJECT: hello SPF: %s 550 %s' % (hres,htxt))
self.setreply('550','5.7.1',htxt,
"The hostname given in your MTA's HELO response is not listed",
"as a legitimate MTA in the SPF records for your domain. If you",
"get this bounce, the message was not in fact a forgery, and you",
"should IMMEDIATELY notify your email administrator of the problem."
)
return Milter.REJECT
if hres == 'none' and spf_best_guess \
and not dynip(self.hello_name,self.connectip):
hres,hcode,htxt = h.best_guess()
else: hres = res
ores = res
if spf_best_guess and res == 'none':
#self.log('SPF: no record published, guessing')
q.set_default_explanation(
'SPF guess: see http://openspf.org/why.html')
# best_guess should not result in fail
if self.missing_ptr:
# ignore dynamic PTR for best guess
res,code,txt = q.best_guess('v=spf1 a/24 mx/24')
else:
res,code,txt = q.best_guess()
if q.perm_error: # FIXME: should never happen?
res,code,txt = q.perm_error.ext # extended result
txt = 'EXT: ' + txt
if self.missing_ptr and ores == 'none' and res != 'pass' \
and hres != 'pass':
policy = p.getNonePolicy()
if policy == 'CBV':
if self.mailfrom != '<>':
q.result = ores
self.cbv_needed = q # accept, but inform sender via DSN
elif policy != 'OK':
self.log('REJECT: no PTR, HELO or SPF')
self.setreply('550','5.7.1',
"You must have a valid HELO or publish SPF: http://www.openspf.org ",
"Contact your mail administrator IMMEDIATELY! Your mail server is ",
"severely misconfigured. It has no PTR record (dynamic PTR records ",
"that contain your IP don't count), an invalid or dynamic HELO, ",
"and no SPF record."
)
return Milter.REJECT
if res in ('deny', 'fail'):
policy = p.getFailPolicy()
if hres == 'pass' and policy == 'CBV':
if self.mailfrom != '<>':
self.cbv_needed = q
elif policy != 'OK':
self.log('REJECT: SPF %s %i %s' % (res,code,txt))
self.setreply(str(code),'5.7.1',txt)
# A proper SPF fail error message would read:
# forger.biz [1.2.3.4] is not allowed to send mail with the domain
# "forged.org" in the sender address. Contact <postmaster@forged.org>.
return Milter.REJECT
if res == 'softfail':
policy = p.getSoftfailPolicy()
if policy == 'CBV' and hres == 'pass':
if self.mailfrom != '<>':
self.cbv_needed = q
elif policy != 'OK':
self.log('REJECT: SPF %s %i %s' % (res,code,txt))
self.setreply('550','5.7.1',
'SPF softfail: If you get this Delivery Status Notice, your email',
'was probably legitimate. Your administrator has published SPF',
'records in a testing mode. The SPF record reported your email as',
'a forgery, which is a mistake if you are reading this. Please',
'notify your administrator of the problem immediately.'
)
return Milter.REJECT
if res == 'neutral':
policy = p.getNeutralPolicy()
if policy == 'CBV' and hres == 'pass':
if self.mailfrom != '<>':
self.cbv_needed = q
q.result = res # select neutral DSN template
elif policy != 'OK':
self.log('REJECT: SPF neutral for',q.s)
self.setreply('550','5.7.1',
'mail from %s must pass SPF: http://openspf.org/why.html' % q.o,
'The %s domain is one that spammers love to forge. Due to' % q.o,
'the volume of forged mail, we can only accept mail that',
'the SPF record for %s explicitly designates as legitimate.' % q.o,
'Sending your email through the recommended outgoing SMTP',
'servers for %s should accomplish this.' % q.o
)
return Milter.REJECT
if res in ('unknown','permerror'):
policy = p.getPermErrorPolicy()
if policy == 'CBV' and hres == 'pass':
if self.mailfrom != '<>':
self.cbv_needed = q
elif policy != 'OK':
self.log('REJECT: SPF %s %i %s' % (res,code,txt))
# latest SPF draft recommends 5.5.2 instead of 5.7.1
self.setreply(str(code),'5.5.2',txt,
'There is a fatal syntax error in the SPF record for %s' % q.o,
'We cannot accept mail from %s until this is corrected.' % q.o
)
return Milter.REJECT
if res in ('error','temperror'):
self.log('TEMPFAIL: SPF %s %i %s' % (res,code,txt))
self.setreply(str(code),'4.3.0',txt)
return Milter.TEMPFAIL
self.add_header('Received-SPF',q.get_header(q.result,receiver),0)
if res != q.result:
self.add_header('X-Guessed-SPF',res,0)
self.spf = q
if res == 'pass' and auto_whitelist.has_key(self.canon_from):
self.whitelist = True
self.log("WHITELIST",self.canon_from)
if gossip:
if res == 'pass':
qual = 'SPF'
else:
qual = self.connectip
self.umis = gossip.umis(q.o+qual,self.id+time.time())
res,hdr,val = gossip_node.query(self.umis,q.o,qual,1)
self.add_header(hdr,val)
return Milter.CONTINUE
# hide_path causes a copy of the message to be saved - until we
# track header mods separately from body mods - so use only
# in emergencies.
def envrcpt(self,to,*str):
# mail to MAILER-DAEMON is generally spam that bounced
if to.startswith('<MAILER-DAEMON@'):
self.log('DISCARD: RCPT TO:',to,str)
return Milter.DISCARD
self.log("rcpt to",to,str)
t = parse_addr(to)
if len(t) == 2:
t[1] = t[1].lower()
user,domain = t
if self.is_bounce and srs and domain in srs_domain:
oldaddr = '@'.join(parse_addr(to))
try:
if ses:
newaddr = ses.verify(oldaddr)
else:
newaddr = oldaddr,
if len(newaddr) > 1:
self.log("ses rcpt:",newaddr[0])
else:
newaddr = srs.reverse(oldaddr)
# Currently, a sendmail map reverses SRS. We just log it here.
self.log("srs rcpt:",newaddr)
self.dspam = False # verified as reply to mail we sent
except:
if not (self.internal_connection or self.trusted_relay):
if srsre.match(oldaddr):
self.log("REJECT: srs spoofed:",oldaddr)
self.setreply('550','5.7.1','Invalid SRS signature')
return Milter.REJECT
if oldaddr.startswith('SES='):
self.log("REJECT: ses spoofed:",oldaddr)
self.setreply('550','5.7.1','Invalid SES signature')
return Milter.REJECT
self.data_allowed = not srs_reject_spoofed
# non DSN mail to SRS address will bounce due to invalid local part
canon_to = '@'.join(t)
self.recipients.append(canon_to)
users = check_user.get(domain)
if self.discard:
self.del_recipient(to)
if users and not user in users:
self.log('REJECT: RCPT TO:',to)
return Milter.REJECT
if user in block_forward.get(domain,()):
self.forward = False
exempt_users = dspam_exempt.get(domain,())
if user in exempt_users or '' in exempt_users:
self.dspam = False
if domain in hide_path:
self.hidepath = True
if not domain in dspam_reject:
self.reject_spam = False
if self.internal_connection and self.whitelist_sender:
if internal_domains:
for pat in internal_domains:
if fnmatchcase(domain,pat): break
else:
auto_whitelist[canon_to] = None
else:
auto_whitelist[canon_to] = None
self.smart_alias(to)
# get recipient after virtusertable aliasing
#rcpt = self.getsymval("{rcpt_addr}")
#self.log("rcpt-addr",rcpt);
return Milter.CONTINUE
# Heuristic checks for spam headers
def check_header(self,name,val):
lname = name.lower()
# val is decoded header value
if lname == 'subject':
# check for common spam keywords
for wrd in spam_words:
if val.find(wrd) >= 0:
self.log('REJECT: %s: %s' % (name,val))
self.setreply('550','5.7.1','That subject is not allowed')
return Milter.REJECT
# check for spam that claims to be legal
lval = val.lower().strip()
for adv in ("adv:","adv.","adv ","[adv]","(adv)","advt:","advert:"):
if lval.startswith(adv):
self.log('REJECT: %s: %s' % (name,val))
self.setreply('550','5.7.1','Advertising not accepted here')
return Milter.REJECT
for adv in ("adv","(adv)","[adv]"):
if lval.endswith(adv):
self.log('REJECT: %s: %s' % (name,val))
self.setreply('550','5.7.1','Advertising not accepted here')
return Milter.REJECT
# check for porn keywords
for w in porn_words:
if lval.find(w) >= 0:
self.log('REJECT: %s: %s' % (name,val))
self.setreply('550','5.7.1','That subject is not allowed')
return Milter.REJECT
# check for annoying forwarders
if not self.forward:
if lval.startswith("fwd:") or lval.startswith("[fw"):
self.log('REJECT: %s: %s' % (name,val))
self.setreply('550','5.7.1','I find unedited forwards annoying')
return Milter.REJECT
# check for invalid message id
if lname == 'message-id' and len(val) < 4:
self.log('REJECT: %s: %s' % (name,val))
return Milter.REJECT
# check for common bulk mailers
if lname == 'x-mailer':
mailer = val.lower()
if mailer in ('direct email','calypso','mail bomber') \
or mailer.find('optin') >= 0:
self.log('REJECT: %s: %s' % (name,val))
return Milter.REJECT
return Milter.CONTINUE
def forged_bounce(self):
if self.mailfrom != '<>':
self.log("REJECT: bogus DSN")
self.setreply('550','5.7.1',
"I do not accept mail from postmaster, mailer-daemon, or clamav.",
"All such mail has turned out to be Delivery Status Notifications",
"which failed to be marked as such. Please send a real DSN if",
"you need to. Use another MAIL FROM if you need to send me mail."
)
else:
self.log('REJECT: bounce with no SRS encoding')
self.setreply('550','5.7.1',
"I did not send you that message. Please consider implementing SPF",
"(http://openspf.org) to avoid bouncing mail to spoofed senders.",
"Thank you."
)
return Milter.REJECT
def header(self,name,hval):
if not self.data_allowed:
return self.forged_bounce()
lname = name.lower()
# decode near ascii text to unobfuscate
val = parse_header(hval)
if not self.internal_connection:
# even if we wanted the Taiwanese spam, we can't read Chinese
if block_chinese and lname == 'subject':
if val.startswith('=?big5') or val.startswith('=?ISO-2022-JP'):
self.log('REJECT: %s: %s' % (name,val))
self.setreply('550','5.7.1',"We don't understand chinese")
return Milter.REJECT
rc = self.check_header(name,val)
if rc != Milter.CONTINUE: return rc
# log selected headers
if log_headers or lname in ('subject','x-mailer'):
self.log('%s: %s' % (name,val))
elif self.trust_received and lname == 'received':
self.trust_received = False
self.log('%s: %s' % (name,val.splitlines()[0]))
elif self.trust_spf and lname == 'received-spf':
self.trust_spf = False
self.log('%s: %s' % (name,val.splitlines()[0]))
if self.fp:
try:
val = val.encode('us-ascii')
except:
val = hval
self.fp.write("%s: %s\n" % (name,val)) # add header to buffer
return Milter.CONTINUE
def eoh(self):
if not self.fp: return Milter.TEMPFAIL # not seen by envfrom
if not self.data_allowed:
return self.forged_bounce()
for name,val,idx in self.new_headers:
self.fp.write("%s: %s\n" % (name,val)) # add new headers to buffer
self.fp.write("\n") # terminate headers
# log when neither sender nor from domains matches mail from domain
if supply_sender and self.mailfrom != '<>' and not self.internal_connection:
mf_domain = self.canon_from.split('@')[-1]
self.fp.seek(0)
msg = rfc822.Message(self.fp)
for rn,hf in msg.getaddrlist('from')+msg.getaddrlist('sender'):
t = parse_addr(hf)
if len(t) == 2:
hd = t[1].lower()
if hd == mf_domain or mf_domain.endswith('.'+hd): break
else:
for f in msg.getallmatchingheaders('from'):
self.log(f)
sender = msg.getallmatchingheaders('sender')
if sender:
for f in sender:
self.log(f)
else:
self.log("NOTE: Supplying MFROM as Sender");
self.add_header('Sender',self.mailfrom)
del msg
# copy headers to a temp file for scanning the body
self.fp.seek(0)
headers = self.fp.getvalue()
self.fp.close()
fd,fname = tempfile.mkstemp(".defang")
self.tempname = fname
self.fp = os.fdopen(fd,"w+b")
self.fp.write(headers) # IOError (e.g. disk full) causes TEMPFAIL
# check if headers are really spammy
if dspam_dict and not self.internal_connection:
ds = dspam.dspam(dspam_dict,dspam.DSM_PROCESS,
dspam.DSF_CHAINED|dspam.DSF_CLASSIFY)
try:
ds.process(headers)
if ds.probability > 0.93 and self.dspam and not self.whitelist:
self.log('REJECT: X-DSpam-HeaderScore: %f' % ds.probability)
self.setreply('550','5.7.1','Your Message looks spammy')
return Milter.REJECT
self.add_header('X-DSpam-HeaderScore','%f'%ds.probability)
finally:
ds.destroy()
return Milter.CONTINUE
def body(self,chunk): # copy body to temp file
if self.fp:
self.fp.write(chunk) # IOError causes TEMPFAIL in milter
self.bodysize += len(chunk)
return Milter.CONTINUE
def _headerChange(self,msg,name,value):
if value: # add header
self.addheader(name,value)
else: # delete all headers with name
h = msg.getheaders(name)
if h:
for i in range(len(h),0,-1):
self.chgheader(name,i-1,'')
def _chk_ext(self,name):
"Check a name for dangerous Winblows extensions."
if not name: return name
lname = name.lower()
for ext in self.bad_extensions:
if lname.endswith(ext): return name
return None
def _chk_attach(self,msg):
"Filter attachments by content."
# check for bad extensions
mime.check_name(msg,self.tempname,ckname=self._chk_ext,scan_zip=scan_zip)
# remove scripts from HTML
if scan_html:
mime.check_html(msg,self.tempname)
# don't let a tricky virus slip one past us
if scan_rfc822:
msg = msg.get_submsg()
if isinstance(msg,email.Message.Message):
return mime.check_attachments(msg,self._chk_attach)
return Milter.CONTINUE
def alter_recipients(self,discard_list,redirect_list):
for rcpt in discard_list:
if rcpt in redirect_list: continue
self.log("DISCARD RCPT: %s" % rcpt) # log discarded rcpt
self.delrcpt(rcpt)
for rcpt in redirect_list:
if rcpt in discard_list: continue
self.log("APPEND RCPT: %s" % rcpt) # log appended rcpt
self.addrcpt(rcpt)
if not blind_wiretap:
self.addheader('Cc',rcpt)
# check spaminess for recipients in dictionary groups
# if there are multiple users getting dspammed, then
# a signature tag for each is added to the message.
# FIXME: quarantine messages rejected via fixed patterns above
# this will give a fast start to stats
def check_spam(self):
"return True/False if self.fp, else return Milter.REJECT/TEMPFAIL/etc"
if not dspam_userdir: return False
ds = Dspam.DSpamDirectory(dspam_userdir)
ds.log = self.log
ds.headerchange = self._headerChange
modified = False
for rcpt in self.recipients:
if dspam_users.has_key(rcpt.lower()):
user = dspam_users.get(rcpt.lower())
if user:
try:
self.fp.seek(0)
txt = self.fp.read()
if user == 'spam' and self.internal_connection:
sender = dspam_users.get(self.canon_from)
if sender:
self.log("SPAM: %s" % sender) # log user for FP
ds.add_spam(sender,txt)
txt = None
self.fp = None
return Milter.DISCARD
elif user == 'falsepositive' and self.internal_connection:
sender = dspam_users.get(self.canon_from)
if sender:
self.log("FP: %s" % sender) # log user for FP
txt = ds.false_positive(sender,txt)
self.fp = StringIO.StringIO(txt)
self.delrcpt('<%s>' % rcpt)
self.recipients = None
self.rejectvirus = False
return True
elif not self.internal_connection or dspam_internal:
if len(txt) > dspam_sizelimit:
self.log("Large message:",len(txt))
return False
if user == 'honeypot' and Dspam.VERSION >= '1.1.9':
keep = False # keep honeypot mail
self.fp = None
if len(self.recipients) > 1:
self.log("HONEYPOT:",rcpt,'SCREENED')
if self.whitelist:
# don't train when recipients includes honeypot
return False
if self.spf and self.mailfrom != '<>':
# check that sender accepts quarantine DSN
msg = mime.message_from_file(StringIO.StringIO(txt))
rc = self.send_dsn(self.spf,msg,'quarantine.txt')
del msg
if rc != Milter.CONTINUE:
return rc
ds.check_spam(user,txt,self.recipients,quarantine=True,
force_result=dspam.DSR_ISSPAM)
else:
ds.check_spam(user,txt,self.recipients,quarantine=keep,
force_result=dspam.DSR_ISSPAM)
self.log("HONEYPOT:",rcpt)
return Milter.DISCARD
if self.whitelist:
# Sender whitelisted: tag, but force as ham.
# User can change if actually spam.
txt = ds.check_spam(user,txt,self.recipients,
force_result=dspam.DSR_ISINNOCENT)
else:
txt = ds.check_spam(user,txt,self.recipients)
if not txt:
# DISCARD if quarrantined for any recipient. It
# will be resent to all recipients if they submit
# as a false positive.
self.log("DSPAM:",user,rcpt)
self.fp = None
return Milter.DISCARD
self.fp = StringIO.StringIO(txt)
modified = True
except Exception,x:
self.log("check_spam:",x)
milter_log.error("check_spam: %s",x,exc_info=True)
# screen if no recipients are dspam_users
if not modified and dspam_screener and not self.internal_connection \
and self.dspam:
self.fp.seek(0)
txt = self.fp.read()
if len(txt) > dspam_sizelimit:
self.log("Large message:",len(txt))
return False
screener = dspam_screener[self.id % len(dspam_screener)]
if not ds.check_spam(screener,txt,self.recipients,
classify=True,quarantine=False):
if self.whitelist:
# messages is whitelisted but looked like spam, Train on Error
self.log("TRAIN:",screener,'X-Dspam-Score: %f' % ds.probability)
# user can't correct anyway if really spam, so discard tag
ds.check_spam(screener,txt,self.recipients,
force_result=dspam.DSR_ISINNOCENT)
return False
if self.reject_spam:
self.log("DSPAM:",screener,
'REJECT: X-DSpam-Score: %f' % ds.probability)
self.setreply('550','5.7.1','Your Message looks spammy')
self.fp = None
return Milter.REJECT
self.log("DSPAM:",screener,"SCREENED")
if self.spf and self.mailfrom != '<>':
# check that sender accepts quarantine DSN
self.fp.seek(0)
msg = mime.message_from_file(self.fp)
rc = self.send_dsn(self.spf,msg,'quarantine.txt')
if rc != Milter.CONTINUE:
self.fp = None
return rc
del msg
if not ds.check_spam(screener,txt,self.recipients,classify=True):
self.fp = None
return Milter.DISCARD
# Message no longer looks spammy, deliver normally. We lied in the DSN.
return modified
def eom(self):
if not self.fp:
return Milter.ACCEPT # no message collected - so no eom processing
try:
# analyze external mail for spam
spam_checked = self.check_spam() # tag or quarantine for spam
if not self.fp:
if gossip and self.umis:
gossip_node.feedback(self.umis,1)
return spam_checked
# analyze all mail for dangerous attachments and scripts
self.fp.seek(0)
msg = mime.message_from_file(self.fp)
# pass header changes in top level message to sendmail
msg.headerchange = self._headerChange
# filter leaf attachments through _chk_attach
assert not msg.ismodified()
self.bad_extensions = ['.' + x for x in banned_exts]
rc = mime.check_attachments(msg,self._chk_attach)
except: # milter crashed trying to analyze mail
exc_type,exc_value = sys.exc_info()[0:2]
if dspam_userdir and exc_type == dspam.error:
if not exc_value.strerror:
exc_value.strerror = exc_value.args[0]
if exc_value.strerror == 'Lock failed':
milter_log.warn("LOCK: BUSY") # log filename
self.setreply('450','4.2.0',
'Too busy discarding spam. Please try again later.')
return Milter.TEMPFAIL
fname = tempfile.mktemp(".fail") # save message that caused crash
os.rename(self.tempname,fname)
self.tempname = None
if exc_type == email.Errors.BoundaryError:
milter_log.warn("MALFORMED: %s",fname) # log filename
if self.internal_connection:
# accept anyway for now
return Milter.ACCEPT
self.setreply('554','5.7.7',
'Boundary error in your message, are you a spammer?')
return Milter.REJECT
if exc_type == email.Errors.HeaderParseError:
milter_log.warn("MALFORMED: %s",fname) # log filename
self.setreply('554','5.7.7',
'Header parse error in your message, are you a spammer?')
return Milter.REJECT
milter_log.error("FAIL: %s",fname) # log filename
# let default exception handler print traceback and return 451 code
raise
if rc == Milter.REJECT: return rc;
if rc == Milter.DISCARD: return rc;
if rc == Milter.CONTINUE: rc = Milter.ACCEPT # for testbms.py compat
defanged = msg.ismodified()
if self.hidepath: del msg['Received']
if self.recipients == None:
# false positive being recirculated
self.recipients = msg.get_all('x-dspam-recipients',[])
if self.recipients:
for rcptlist in self.recipients:
for rcpt in rcptlist.split(','):
self.addrcpt('<%s>' % rcpt.strip())
del msg['x-dspam-recipients']
else:
self.addrcpt(self.mailfrom)
else:
self.alter_recipients(self.discard_list,self.redirect_list)
for name,val,idx in self.new_headers:
try:
self.addheader(name,val,idx)
except:
self.addheader(name,val) # older sendmail can't insheader
if self.cbv_needed:
q = self.cbv_needed
if q.result in ('softfail','fail','deny'):
template_name = 'softfail.txt'
elif q.result in ('unknown','permerror'):
template_name = 'permerror.txt'
elif q.result == 'neutral':
template_name = 'neutral.txt'
else:
template_name = 'strike3.txt'
rc = self.send_dsn(q,msg,template_name)
self.cbv_needed = None
if rc != Milter.CONTINUE: return rc
if not defanged and not spam_checked:
os.remove(self.tempname)
self.tempname = None # prevent re-removal
self.log("eom")
return rc # no modified attachments
# Body modified, copy modified message to a temp file
if defanged:
if self.rejectvirus and not self.hidepath:
self.log("REJECT virus from",self.mailfrom)
self.setreply('550','5.7.1','Attachment type not allowed.',
'You attempted to send an attachment with a banned extension.')
self.tempname = None
return Milter.REJECT
self.log("Temp file:",self.tempname)
self.tempname = None # prevent removal of original message copy
out = tempfile.TemporaryFile()
try:
msg.dump(out)
out.seek(0)
msg = rfc822.Message(out)
msg.rewindbody()
while True:
buf = out.read(8192)
if len(buf) == 0: break
self.replacebody(buf) # feed modified message to sendmail
if spam_checked:
if gossip and self.umis:
gossip_node.feedback(self.umis,0)
self.log("dspam")
return rc
finally:
out.close()
return Milter.TEMPFAIL
def send_dsn(self,q,msg,template_name):
sender = q.s
cached = cbv_cache.has_key(sender)
if cached:
self.log('CBV:',sender,'(cached)')
res = cbv_cache[sender]
else:
self.log('CBV:',sender)
try:
template = file(template_name).read()
except IOError: template = None
m = dsn.create_msg(q,self.recipients,msg,template)
m = m.as_string()
print >>open('last_dsn','w'),m
res = dsn.send_dsn(sender,self.receiver,m)
if res:
desc = "CBV: %d %s" % res[:2]
if 400 <= res[0] < 500:
self.log('TEMPFAIL:',desc)
self.setreply('450','4.2.0',*desc.splitlines())
return Milter.TEMPFAIL
if len(res) < 3: res += time.time(),
cbv_cache[sender] = res
self.log('REJECT:',desc)
self.setreply('550','5.7.1',*desc.splitlines())
return Milter.REJECT
cbv_cache[sender] = res
return Milter.CONTINUE
def close(self):
if self.tempname:
os.remove(self.tempname) # remove in case session aborted
if self.fp:
self.fp.close()
return Milter.CONTINUE
def abort(self):
self.log("abort after %d body chars" % self.bodysize)
return Milter.CONTINUE
def main():
Milter.factory = bmsMilter
flags = Milter.CHGBODY + Milter.CHGHDRS + Milter.ADDHDRS
if wiretap_dest or smart_alias or dspam_userdir:
flags = flags + Milter.ADDRCPT
if srs or len(discard_users) > 0 or smart_alias or dspam_userdir:
flags = flags + Milter.DELRCPT
Milter.set_flags(flags)
milter_log.info("bms milter startup")
sys.stdout.flush()
Milter.runmilter("pythonfilter",socketname,timeout)
milter_log.info("bms milter shutdown")
if __name__ == "__main__":
read_config(["/etc/mail/pymilter.cfg","milter.cfg"])
if dspam_dict:
import dspam # low level spam check
if dspam_userdir:
import dspam
import Dspam # high level spam check
try:
dspam_version = Dspam.VERSION
except:
dspam_version = '1.1.4'
assert dspam_version >= '1.1.5'
main()
Reference in New Issue View Git Blame Copy Permalink