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# Copyright (C) 2007-2016 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/>.
"""Look for moderator pre-approval."""
__all__ = [
'Approved',
]
import re
from email.iterators import typed_subpart_iterator
from mailman.config import config
from mailman.core.i18n import _
from mailman.interfaces.rules import IRule
from zope.interface import implementer
EMPTYSTRING = ''
HEADERS = [
'approve',
'approved',
'x-approve',
'x-approved',
]
@implementer(IRule)
class Approved:
"""Look for moderator pre-approval."""
name = 'approved'
description = _('The message has a matching Approve or Approved header.')
record = True
def _get_password(self, msg, missing):
for header in HEADERS:
password = msg.get(header, missing)
if password is not missing:
return password
return missing
def check(self, mlist, msg, msgdata):
"""See `IRule`."""
if mlist.moderator_password is None:
return False
# See if the message has an Approved or Approve header with a valid
# moderator password. Also look at the first non-whitespace line in
# the file to see if it looks like an Approved header.
missing = object()
password = self._get_password(msg, missing)
if password is missing:
# Find the first text/plain part in the message
part = None
stripped = False
payload = None
for part in typed_subpart_iterator(msg, 'text', 'plain'):
payload = part.get_payload(decode=True)
break
if payload is not None:
charset = part.get_content_charset('us-ascii')
try:
# Do the decoding inside the try/except so that if the
# charset is unknown, we'll just drop back to ascii.
payload = payload.decode(charset, 'replace')
except LookupError:
# Unknown or empty charset.
payload = payload.decode('us-ascii', 'replace')
line = ''
lines = payload.splitlines(True)
for lineno, line in enumerate(lines):
if line.strip() != '':
break
if ':' in line:
header, value = line.split(':', 1)
if header.lower() in HEADERS:
password = value.strip()
# Now strip the first line from the payload so the
# password doesn't leak.
del lines[lineno]
reset_payload(part, EMPTYSTRING.join(lines))
stripped = True
if stripped:
# Now try all the text parts in case it's
# multipart/alternative with the approved line in HTML or
# other text part. We make a pattern from the Approved line
# and delete it from all text/* parts in which we find it. It
# would be better to just iterate forward, but email
# compatability for pre Python 2.2 returns a list, not a true
# iterator.
#
# This will process all the multipart/alternative parts in the
# message as well as all other text parts. We shouldn't find
# the pattern outside the multipart/alternative parts, but if
# we do, it is probably best to delete it anyway as it does
# contain the password.
#
# Make a pattern to delete. We can't just delete a line
# because line of HTML or other fancy text may include
# additional message text. This pattern works with HTML. It
# may not work with rtf or whatever else is possible.
pattern = header + ':(\s| )*' + re.escape(password)
for part in typed_subpart_iterator(msg, 'text'):
payload = part.get_payload()
if payload is not None:
if re.search(pattern, payload):
reset_payload(part, re.sub(pattern, '', payload))
else:
for header in HEADERS:
del msg[header]
if password is missing:
return False
is_valid, new_hash = config.password_context.verify(
password, mlist.moderator_password)
if is_valid and new_hash:
# Hash algorithm migration.
mlist.moderator_password = new_hash
return is_valid
def reset_payload(part, payload):
# Set decoded payload maintaining content-type, charset, format and delsp.
charset = part.get_content_charset() or 'us-ascii'
content_type = part.get_content_type()
format = part.get_param('format')
delsp = part.get_param('delsp')
del part['content-transfer-encoding']
del part['content-type']
part.set_payload(payload, charset)
part.set_type(content_type)
if format:
part.set_param('Format', format)
if delsp:
part.set_param('DelSp', delsp)
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