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# Copyright (C) 2007-2009 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman 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.
#
# GNU Mailman 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
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""The historical 'suspicious header' rule."""
from __future__ import absolute_import, unicode_literals
__metaclass__ = type
__all__ = [
'SuspiciousHeader',
]
import re
import logging
from zope.interface import implements
from mailman.i18n import _
from mailman.interfaces.rules import IRule
log = logging.getLogger('mailman.error')
class SuspiciousHeader:
"""The historical 'suspicious header' rule."""
implements(IRule)
name = 'suspicious-header'
description = _('Catch messages with suspicious headers.')
record = True
def check(self, mlist, msg, msgdata):
"""See `IRule`."""
return (mlist.bounce_matching_headers and
has_matching_bounce_header(mlist, msg))
def _parse_matching_header_opt(mlist):
"""Return a list of triples [(field name, regex, line), ...]."""
# - Blank lines and lines with '#' as first char are skipped.
# - Leading whitespace in the matchexp is trimmed - you can defeat
# that by, eg, containing it in gratuitous square brackets.
all = []
for line in mlist.bounce_matching_headers.splitlines():
line = line.strip()
# Skip blank lines and lines *starting* with a '#'.
if not line or line.startswith('#'):
continue
i = line.find(':')
if i < 0:
# This didn't look like a header line. BAW: should do a
# better job of informing the list admin.
log.error('bad bounce_matching_header line: %s\n%s',
mlist.real_name, line)
else:
header = line[:i]
value = line[i+1:].lstrip()
try:
cre = re.compile(value, re.IGNORECASE)
except re.error as error:
# The regexp was malformed. BAW: should do a better
# job of informing the list admin.
log.error("""\
bad regexp in bounce_matching_header line: %s
\n%s (cause: %s)""", mlist.real_name, value, error)
else:
all.append((header, cre, line))
return all
def has_matching_bounce_header(mlist, msg):
"""Does the message have a matching bounce header?
:param mlist: The mailing list the message is destined for.
:param msg: The email message object.
:return: True if a header field matches a regexp in the
bounce_matching_header mailing list variable.
"""
for header, cre, line in _parse_matching_header_opt(mlist):
for value in msg.get_all(header, []):
if cre.search(value):
return True
return False
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