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diff --git a/src/mailman/handlers/dmarc.py b/src/mailman/handlers/dmarc.py
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+++ b/src/mailman/handlers/dmarc.py
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+# Copyright (C) 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/>.
+
+"""Do DMARC Munge From and Wrap Message actions."""
+
+import re
+import copy
+import logging
+
+from email.header import Header
+from email.mime.message import MIMEMessage
+from email.mime.text import MIMEText
+from email.utils import formataddr, getaddresses, make_msgid
+from mailman import public
+from mailman.core.i18n import _
+from mailman.interfaces.handler import IHandler
+from mailman.interfaces.mailinglist import (
+    DMARCModerationAction, FromIsList, ReplyToMunging)
+from mailman.utilities.string import wrap
+from zope.interface import implementer
+
+
+log = logging.getLogger('mailman.error')
+
+COMMASPACE = ', '
+MAXLINELEN = 78
+NONASCII = re.compile('[^\s!-~]')
+# Headers from the original that we want to keep in the wrapper.  These are
+# actually regexps matched with re.match so they match anything that starts
+# with the given string unless they end with '$'.
+KEEPERS = ('archived-at',
+           'date',
+           'in-reply-to',
+           'list-',
+           'precedence',
+           'references',
+           'to',
+           'x-mailman-',
+           )
+
+
+@public
+def uheader(mlist, s, header_name=None, continuation_ws='\t', maxlinelen=None):
+    """Get the charset to encode the string in.
+
+    Then search if there is any non-ascii character is in the string.  If
+    there is and the charset is us-ascii then we use iso-8859-1 instead.  If
+    the string is ascii only we use 'us-ascii' if another charset is
+    specified.
+
+    If the header contains a newline, truncate it (see GL#273).
+    """
+    charset = mlist.preferred_language.charset
+    if NONASCII.search(s):
+        # use list charset but ...
+        if charset == 'us-ascii':
+            charset = 'iso-8859-1'
+    else:
+        # there is no non-ascii so ...
+        charset = 'us-ascii'
+    if '\n' in s:
+        s = '{} [...]'.format(s.split('\n')[0])
+        log.warning('Header {} contains a newline, truncating it.'.format(
+            header_name, s))
+    return Header(s, charset, maxlinelen, header_name, continuation_ws)
+
+
+def munged_headers(mlist, msg, msgdata):
+    # Be as robust as possible here.
+    faddrs = getaddresses(msg.get_all('from', []))
+    # Strip the nulls and bad emails.
+    faddrs = [x for x in faddrs if x[1].find('@') > 0]
+    if len(faddrs) == 1:
+        realname, email = o_from = faddrs[0]
+    else:
+        # No From: or multiple addresses.  Just punt and take
+        # the get_sender result.
+        realname = ''
+        email = msgdata['original_sender']
+        o_from = (realname, email)
+    if not realname:
+        member = mlist.members.get_member(email)
+        if member:
+            realname = member.display_name or email
+        else:
+            realname = email
+    # Remove domain from realname if it looks like an email address
+    realname = re.sub(r'@([^ .]+\.)+[^ .]+$', '---', realname)
+    # RFC 2047 encode realname if necessary.
+    realname = str(uheader(mlist, realname))
+    lrn = mlist.display_name                         # noqa F841
+    retn = [('From', formataddr((_('$realname via $lrn'),
+                                mlist.posting_address)))]
+    # We've made the munged From:.  Now put the original in Reply-To: or Cc:
+    if mlist.reply_goes_to_list == ReplyToMunging.no_munging:
+        # Add original from to Reply-To:
+        add_to = 'Reply-To'
+    else:
+        # Add original from to Cc:
+        add_to = 'Cc'
+    orig = getaddresses(msg.get_all(add_to, []))
+    if o_from[1] not in [x[1] for x in orig]:
+        orig.append(o_from)
+    retn.append((add_to, COMMASPACE.join([formataddr(x) for x in orig])))
+    return retn
+
+
+def munge_from(mlist, msg, msgdata):
+    for k, v in munged_headers(mlist, msg, msgdata):
+        del msg[k]
+        msg[k] = v
+    return
+
+
+def wrap_message(mlist, msg, msgdata, dmarc_wrap=False):
+    # Create a wrapper message around the original.
+    # There are various headers in msg that we don't want, so we basically
+    # make a copy of the msg, then delete almost everything and set/copy
+    # what we want.
+    omsg = copy.deepcopy(msg)
+    for key in msg.keys():
+        keep = False
+        for keeper in KEEPERS:
+            if re.match(keeper, key, re.I):
+                keep = True
+                break
+        if not keep:
+            del msg[key]
+    msg['MIME-Version'] = '1.0'
+    msg['Message-ID'] = make_msgid()
+    for k, v in munged_headers(mlist, omsg, msgdata):
+        msg[k] = v
+    # Are we including dmarc_wrapped_message_text?  I.e., do we have text and
+    # are we wrapping because of dmarc_moderation_action?
+    if mlist.dmarc_wrapped_message_text and dmarc_wrap:
+        part1 = MIMEText(wrap(mlist.dmarc_wrapped_message_text),
+                         'plain',
+                         mlist.preferred_language.charset)
+        part1['Content-Disposition'] = 'inline'
+        part2 = MIMEMessage(omsg)
+        part2['Content-Disposition'] = 'inline'
+        msg['Content-Type'] = 'multipart/mixed'
+        msg.set_payload([part1, part2])
+    else:
+        msg['Content-Type'] = 'message/rfc822'
+        msg['Content-Disposition'] = 'inline'
+        msg.set_payload([omsg])
+    return
+
+
+def process(mlist, msg, msgdata):
+    """Process DMARC actions."""
+    if ((not msgdata.get('dmarc') or
+            mlist.dmarc_moderation_action == DMARCModerationAction.none) and
+            mlist.from_is_list == FromIsList.none):
+        return
+    if mlist.anonymous_list:
+        # DMARC mitigation is not required for anonymous lists.
+        return
+    if (mlist.dmarc_moderation_action != DMARCModerationAction.none and
+            msgdata.get('dmarc')):
+        if mlist.dmarc_moderation_action == DMARCModerationAction.munge_from:
+            munge_from(mlist, msg, msgdata)
+        elif (mlist.dmarc_moderation_action ==
+                DMARCModerationAction.wrap_message):
+            wrap_message(mlist, msg, msgdata, dmarc_wrap=True)
+        else:
+            assert False, (
+                'handlers/dmarc.py: dmarc_moderation_action = {0}'.format(
+                    mlist.dmarc_moderation_action))
+    else:
+        if mlist.from_is_list == FromIsList.munge_from:
+            munge_from(mlist, msg, msgdata)
+        elif mlist.from_is_list == FromIsList.wrap_message:
+            wrap_message(mlist, msg, msgdata)
+        else:
+            assert False, (
+                'handlers/dmarc.py: from_is_list = {0}'.format(
+                    mlist.from_is_list))
+
+
+@public
+@implementer(IHandler)
+class DMARC:
+    """Apply DMARC mitigations."""
+
+    name = 'dmarc'
+    description = _('Apply DMARC mitigations.')
+
+    def process(self, mlist, msg, msgdata):
+        """See `IHandler`."""
+        process(mlist, msg, msgdata)