A LookupError in SpamDetect on a message with RFC 2047 encoded headers

in an unknown character set is fixed.

2 files changed, 13 insertions, 2 deletions

diff --git a/Mailman/Handlers/SpamDetect.py b/Mailman/Handlers/SpamDetect.py
index 119c5beb..d85cc6a6 100644
--- a/Mailman/Handlers/SpamDetect.py
+++ b/Mailman/Handlers/SpamDetect.py
@@ -1,4 +1,4 @@
-# Copyright (C) 1998-2013 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2015 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
@@ -77,7 +77,15 @@ def getDecodedHeaders(msg, cset='utf-8'):
         for frag, cs in v:
             if not cs:
                 cs = 'us-ascii'
-            uvalue += unicode(frag, cs, 'replace')
+            try:
+                uvalue += unicode(frag, cs, 'replace')
+            except LookupError:
+                # The encoding charset is unknown.  At this point, frag
+                # has been QP or base64 decoded into a byte string whose
+                # charset we don't know how to handle.  We will try to
+                # unicode it as iso-8859-1 which may result in a garbled
+                # mess, but we have to do something.
+                uvalue += unicode(frag, 'iso-8859-1', 'replace')
         headers += '%s: %s\n' % (h, uvalue.encode(cset, 'replace'))
     return headers
 
diff --git a/NEWS b/NEWS
index c2f25ac5..baf770b9 100755
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,9 @@ Here is a history of user visible changes to Mailman.
 
   Bug fixes and other patches
 
+    - A LookupError in SpamDetect on a message with RFC 2047 encoded headers
+      in an unknown character set is fixed.  (LP: #1427389)
+
     - Fixed a bug in CommandRunner that could process the second word of a
       body line as a command word and a case sensitivity in commands in
       Subject: with an Re: prefix.  (LP: #1426829)