- A new mm_cfg.py setting RESPONSE_INCLUDE_LEVEL has been added to control

  how much of the original message is included in automatic responses to
  email commands.  The default is 2 to preserve the prior behavior of
  including the full message.  Setting this to 1 in mm_cfg.py will include
  only the original headers, and 0 will include none of the original.  It
  is recommended to set this to 0 in mm_cfg.py to minimize the effects of
  backscatter.  Bug #265835.

- A new mm_cfg.py setting DEFAULT_RESPOND_TO_POST_REQUESTS has been added
  to control the default for respond_to_post_requests for new lists.  It is
  set to Yes for backwards compatibility, but it is recommended that
  serious consideration be given to setting it to No.  Bug #266051.

- A new mm_cfg.py setting DISCARD_MESSAGE_WITH_NO_COMMAND has been added to
  control whether a message to the -request address without any commands or
  a message to -confirm whose To: address doesn't match VERP_CONFIRM_REGEXP
  is responded to or just logged.  It defaults to Yes which is different
  from prior behavior.  Bug #410236.

4 files changed, 98 insertions, 19 deletions

diff --git a/Mailman/Defaults.py.in b/Mailman/Defaults.py.in
index e1ede271..1bf8362d 100644
--- a/Mailman/Defaults.py.in
+++ b/Mailman/Defaults.py.in
@@ -1,6 +1,6 @@
 # -*- python -*-
 
-# Copyright (C) 1998-2010 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2011 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
@@ -690,7 +690,7 @@ VERP_CONFIRM_FORMAT = '%(addr)s+%(cookie)s'
 # To: "local_part@host" <local_part@host>
 # and may even fold the header when replying, so we skip everything up to '<'
 # if any and include ($s) so dot will match the newline in a folded header.
-VERP_CONFIRM_REGEXP = r'(?s)^(.*<)?(?P<addr>.+)\+(?P<cookie>[^@+]+)@.*$'
+VERP_CONFIRM_REGEXP = r'(?s)^(.*<)?(?P<addr>.+)\+(?P<cookie>[0-9a-f]{40})@.*$'
 
 # Set this to Yes to enable VERP-like (more user friendly) confirmations
 VERP_CONFIRMATIONS = No
@@ -707,6 +707,36 @@ MAX_AUTORESPONSES_PER_DAY = 10
 
 
 #####
+# Backscatter mitigation
+#####
+
+# This controls whether a message to the -request address without any
+# commands or a message to -confirm whose To: address doesn't match
+# VERP_CONFIRM_REGEXP above is responded to or just logged.
+DISCARD_MESSAGE_WITH_NO_COMMAND = Yes
+
+# This controls how much of the original message is included in automatic
+# responses to email commands.  The values are:
+# 0 - Do not include any unprocessed or ignored commands.  Do not include
+#     the original message.
+# 1 - Do not include any unprocessed or ignored commands.  Include only the
+#     headers from the original message.
+# 2 - Include unprocessed and ignored commands.  Include the complete original
+#     message.
+#
+# In order to minimize the effect of backscatter due to spam sent to
+# administrative addresses, it is recommended to set this to 0, however the
+# default is 2 for backwards compatibility.
+RESPONSE_INCLUDE_LEVEL = 2
+
+# This sets the default for respond_to_post_requests for new lists.  It is
+# set to Yes for backwards compatibility, but it is recommended that serious
+# consideration be given to setting it to No.
+DEFAULT_RESPOND_TO_POST_REQUESTS = Yes
+
+
+
+#####
 # Qrunner defaults
 #####
 
diff --git a/Mailman/MailList.py b/Mailman/MailList.py
index a7efd986..504effa7 100644
--- a/Mailman/MailList.py
+++ b/Mailman/MailList.py
@@ -1,4 +1,4 @@
-# Copyright (C) 1998-2010 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2011 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
@@ -314,7 +314,7 @@ class MailList(HTMLFormatter, Deliverer, ListAdmin,
         self.new_member_options = mm_cfg.DEFAULT_NEW_MEMBER_OPTIONS
 
         # This stuff is configurable
-        self.respond_to_post_requests = 1
+        self.respond_to_post_requests = mm_cfg.DEFAULT_RESPOND_TO_POST_REQUESTS
         self.advertised = mm_cfg.DEFAULT_LIST_ADVERTISED
         self.max_num_recipients = mm_cfg.DEFAULT_MAX_NUM_RECIPIENTS
         self.max_message_size = mm_cfg.DEFAULT_MAX_MESSAGE_SIZE
diff --git a/Mailman/Queue/CommandRunner.py b/Mailman/Queue/CommandRunner.py
index 3155f22f..b63b050c 100644
--- a/Mailman/Queue/CommandRunner.py
+++ b/Mailman/Queue/CommandRunner.py
@@ -1,4 +1,4 @@
-# Copyright (C) 1998-2010 by the Free Software Foundation, Inc.
+# Copyright (C) 1998-2011 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
@@ -46,6 +46,10 @@ from email.MIMEText import MIMEText
 from email.MIMEMessage import MIMEMessage
 
 NL = '\n'
+CONTINUE = 0
+STOP = 1
+BADCMD = 2
+BADSUBJ = 3
 
 try:
     True, False
@@ -105,15 +109,19 @@ class Results:
     def process(self):
         # Now, process each line until we find an error.  The first
         # non-command line found stops processing.
-        stop = False
+        found = BADCMD
+        ret = CONTINUE
         for line in self.commands:
             if line and line.strip():
                 args = line.split()
                 cmd = args.pop(0).lower()
-                stop = self.do_command(cmd, args)
+                ret = self.do_command(cmd, args)
+                if ret == STOP or ret == CONTINUE:
+                    found = ret
             self.lineno += 1
-            if stop:
+            if ret == STOP or ret == BADCMD:
                 break
+        return found
 
     def do_command(self, cmd, args=None):
         if args is None:
@@ -136,8 +144,14 @@ class Results:
                 self.subjcmdretried += 1
                 cmd = args.pop(0)
                 return self.do_command(cmd, args)
-            return self.lineno <> 0
-        return handler.process(self, args)
+            if self.lineno <> 0:
+                return BADCMD
+            else:
+                return BADSUBJ
+        if handler.process(self, args):
+            return STOP
+        else:
+            return CONTINUE
 
     def send_response(self):
         # Helper
@@ -156,7 +170,7 @@ Attached is your original message.
         # Ignore empty lines
         unprocessed = [line for line in self.commands[self.lineno:]
                        if line and line.strip()]
-        if unprocessed:
+        if unprocessed and mm_cfg.RESPONSE_INCLUDE_LEVEL >= 2:
             resp.append(_('\n- Unprocessed:'))
             resp.extend(indent(unprocessed))
         if not unprocessed and not self.results:
@@ -165,7 +179,7 @@ Attached is your original message.
 No commands were found in this message.
 To obtain instructions, send a message containing just the word "help".
 """)))
-        if self.ignored:
+        if self.ignored and mm_cfg.RESPONSE_INCLUDE_LEVEL >= 2:
             resp.append(_('\n- Ignored:'))
             resp.extend(indent(self.ignored))
         resp.append(_('\n- Done.\n\n'))
@@ -196,7 +210,15 @@ To obtain instructions, send a message containing just the word "help".
             lang=self.msgdata['lang'])
         msg.set_type('multipart/mixed')
         msg.attach(results)
-        orig = MIMEMessage(self.msg)
+        if mm_cfg.RESPONSE_INCLUDE_LEVEL == 1:
+            self.msg.set_payload(
+                _('Message body suppressed by Mailman site configuration\n'))
+        if mm_cfg.RESPONSE_INCLUDE_LEVEL == 0:
+            orig = MIMEText(_(
+                'Original message suppressed by Mailman site configuration\n'
+                ), _charset=charset)
+        else:
+            orig = MIMEMessage(self.msg)
         msg.attach(orig)
         msg.send(self.mlist)
 
@@ -236,17 +258,23 @@ class CommandRunner(Runner):
         # mylist-join, or mylist-leave, and the message metadata will contain
         # a key to which one was used.
         try:
+            ret = BADCMD
             if msgdata.get('torequest'):
-                res.process()
+                ret = res.process()
             elif msgdata.get('tojoin'):
-                res.do_command('join')
+                ret = res.do_command('join')
             elif msgdata.get('toleave'):
-                res.do_command('leave')
+                ret = res.do_command('leave')
             elif msgdata.get('toconfirm'):
                 mo = re.match(mm_cfg.VERP_CONFIRM_REGEXP, msg.get('to', ''))
                 if mo:
-                    res.do_command('confirm', (mo.group('cookie'),))
-            res.send_response()
-            mlist.Save()
+                    ret = res.do_command('confirm', (mo.group('cookie'),))
+            if ret == BADCMD and mm_cfg.DISCARD_MESSAGE_WITH_NO_COMMAND:
+                syslog('vette',
+                       'No command, message discarded, msgid: %s',
+                       msg.get('message-id', 'n/a'))
+            else:
+                res.send_response()
+                mlist.Save()
         finally:
             mlist.Unlock()
diff --git a/NEWS b/NEWS
index 890e8185..c433caef 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,27 @@ Here is a history of user visible changes to Mailman.
 
 2.1.15 (xx-xxx-xxxx)
 
+  New Features
+
+    - A new mm_cfg.py setting RESPONSE_INCLUDE_LEVEL has been added to control
+      how much of the original message is included in automatic responses to
+      email commands.  The default is 2 to preserve the prior behavior of
+      including the full message.  Setting this to 1 in mm_cfg.py will include
+      only the original headers, and 0 will include none of the original.  It
+      is recommended to set this to 0 in mm_cfg.py to minimize the effects of
+      backscatter.  Bug #265835.
+
+    - A new mm_cfg.py setting DEFAULT_RESPOND_TO_POST_REQUESTS has been added
+      to control the default for respond_to_post_requests for new lists.  It is
+      set to Yes for backwards compatibility, but it is recommended that
+      serious consideration be given to setting it to No.  Bug #266051.
+
+    - A new mm_cfg.py setting DISCARD_MESSAGE_WITH_NO_COMMAND has been added to
+      control whether a message to the -request address without any commands or
+      a message to -confirm whose To: address doesn't match VERP_CONFIRM_REGEXP
+      is responded to or just logged.  It defaults to Yes which is different
+      from prior behavior.  Bug #410236.
+
   i18n
 
     - Fixed a missing format character in the Spanish translation.