Mailman no longer folds long sub-part headers in multipart messages.

In addition, Mailman no longer escapes From_ lines in the body of
messages sent to regular list members, although MTA's may do it anyway.
This is to avoid breaking signatures per Bug #265967.  Changes include
 - Message.py, added a Generator class to avoid header folding and an
   as_string() method wirth a mangle_from_ argument.
 - Mailbox.py, uses new Message.Generator class.
 - SMTPDirect.py, uses as_string(mangle_from_=False) to flatten message.
 - Scrubber.py, removed unused ScrubberGenerator class.

5 files changed, 48 insertions, 27 deletions

diff --git a/Mailman/Handlers/SMTPDirect.py b/Mailman/Handlers/SMTPDirect.py
index 72b587e9..8e3c7d73 100644
--- a/Mailman/Handlers/SMTPDirect.py
+++ b/Mailman/Handlers/SMTPDirect.py
@@ -1,4 +1,4 @@
-# Copyright (C) 1998-2005 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2009 by the Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -360,7 +360,9 @@ def bulkdeliver(mlist, msg, msgdata, envsender, failures, conn):
     msg['Sender'] = envsender
     msg['Errors-To'] = envsender
     # Get the plain, flattened text of the message, sans unixfrom
-    msgtext = msg.as_string()
+    # using our as_string() method to not mangle From_ and not fold
+    # sub-part headers possibly breaking signatures.
+    msgtext = msg.as_string(mangle_from_=False)
     refused = {}
     recips = msgdata['recips']
     msgid = msg['message-id']
diff --git a/Mailman/Handlers/Scrubber.py b/Mailman/Handlers/Scrubber.py
index a990d721..b39f36d2 100644
--- a/Mailman/Handlers/Scrubber.py
+++ b/Mailman/Handlers/Scrubber.py
@@ -90,27 +90,6 @@ def guess_extension(ctype, ext):
     return all and all[0]
 
 
-
-# We're using a subclass of the standard Generator because we want to suppress
-# headers in the subparts of multiparts.  We use a hack -- the ctor argument
-# skipheaders to accomplish this.  It's set to true for the outer Message
-# object, but false for all internal objects.  We recognize that
-# sub-Generators will get created passing only mangle_from_ and maxheaderlen
-# to the ctors.
-#
-# This isn't perfect because we still get stuff like the multipart boundaries,
-# but see below for how we corrupt that to our nefarious goals.
-class ScrubberGenerator(Generator):
-    def __init__(self, outfp, mangle_from_=True,
-                 maxheaderlen=78, skipheaders=True):
-        Generator.__init__(self, outfp, mangle_from_=False)
-        self.__skipheaders = skipheaders
-
-    def _write_headers(self, msg):
-        if not self.__skipheaders:
-            Generator._write_headers(self, msg)
-
-
 def safe_strftime(fmt, t):
     try:
         return time.strftime(fmt, t)
diff --git a/Mailman/Mailbox.py b/Mailman/Mailbox.py
index 03a13840..1b281a4c 100644
--- a/Mailman/Mailbox.py
+++ b/Mailman/Mailbox.py
@@ -1,4 +1,4 @@
-# Copyright (C) 1998-2003 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2009 by the Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -22,10 +22,10 @@ import mailbox
 
 import email
 from email.Parser import Parser
-from email.Generator import Generator
 from email.Errors import MessageParseError
 
 from Mailman import mm_cfg
+from Mailman.Message import Generator
 from Mailman.Message import Message
 
 try:
diff --git a/Mailman/Message.py b/Mailman/Message.py
index 3c2ef605..84e4aa26 100644
--- a/Mailman/Message.py
+++ b/Mailman/Message.py
@@ -1,4 +1,4 @@
-# Copyright (C) 1998-2007 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2009 by the Free Software Foundation, Inc.
 #
 # This program is free software; you can redistribute it and/or
 # modify it under the terms of the GNU General Public License
@@ -17,12 +17,15 @@
 
 """Standard Mailman message object.
 
-This is a subclass of mimeo.Message but provides a slightly extended interface
+This is a subclass of email.Message but provides a slightly extended interface
 which is more convenient for use inside Mailman.
 """
 
 import re
+from cStringIO import StringIO
+
 import email
+import email.Generator
 import email.Message
 import email.Utils
 from email.Charset import Charset
@@ -40,6 +43,24 @@ VERSION = tuple([int(s) for s in mo.group().split('.')])
 
 
 
+class Generator(email.Generator.Generator):
+    """Generates output from a Message object tree, keeping signatures.
+
+       Headers will by default _not_ be folded in attachments.
+    """
+    def __init__(self, outfp, mangle_from_=True,
+                 maxheaderlen=78, children_maxheaderlen=0):
+        email.Generator.Generator.__init__(self, outfp,
+                mangle_from_=mangle_from_, maxheaderlen=maxheaderlen)
+        self.__children_maxheaderlen = children_maxheaderlen
+
+    def clone(self, fp):
+        """Clone this generator with maxheaderlen set for children"""
+        return self.__class__(fp, self._mangle_from_,
+                self.__children_maxheaderlen, self.__children_maxheaderlen)
+
+
+
 class Message(email.Message.Message):
     def __init__(self):
         # We need a version number so that we can optimize __setstate__()
@@ -208,6 +229,20 @@ class Message(email.Message.Message):
             return failobj
 
 
+    def as_string(self, unixfrom=False, mangle_from_=True):
+        """Return entire formatted message as a string using
+        Mailman.Message.Generator.
+
+        Operates like email.Message.Message.as_string, only
+	using Mailman's Message.Generator class. Only the top headers will
+        get folded.
+        """
+        fp = StringIO()
+        g = Generator(fp, mangle_from_=mangle_from_)
+        g.flatten(self, unixfrom=unixfrom)
+        return fp.getvalue()
+
+
 
 class UserNotification(Message):
     """Class for internally crafted messages."""
diff --git a/NEWS b/NEWS
index 47bc5f73..e73c3ff7 100644
--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,11 @@ Here is a history of user visible changes to Mailman.
 
   Bug Fixes and other patches
 
+    - Mailman no longer folds long sub-part headers in multipart messages.
+      In addition, Mailman no longer escapes From_ lines in the body of
+      messages sent to regular list members, although MTA's may do it anyway.
+      This is to avoid breaking signatures per Bug #265967.
+
     - XSS protection in the web interface went too far in escaping HTML
       entities.  Fixed.