[Mailman-Users] Additional questions about ban_list

[Chris Nulk]

Hello all,

I would like to thank Aditya Jain and Mark Sapiro for the help with 
adding my negative regexp to the ban_list.  I apologize for being late 
in my response.  I was OBE'd.

Next, in my original message, I forgot to mention I am using Mailman 
v2.1.18-1 so the kind code assistance Mark provided doesn't quite 
match.  My fault for not putting in the version of Mailman. However, 
looking at the code, it seems to be remarkably similar to code I had to 
modify when using an earlier version of Mailman.

The question now is if I change the following in Mailman/MailList.py

     def GetBannedPattern(self, email):
         """Returns matched entry in ban_list if email matches.
         Otherwise returns None.
         """
         ban = False
         for pattern in self.ban_list:
             if pattern.startswith('^'):
                 # This is a regular expression match
                 try:
                     if re.search(pattern, email, re.IGNORECASE):
                         ban = True
                         break
                 except re.error:
                     # BAW: we should probably remove this pattern
                     pass
             else:
                 # Do the comparison case insensitively
                 if pattern.lower() == email.lower():
                     ban = True
                     break
         if ban:
             return pattern
         else:
             return None

to the following ( I have added ** at the beginning of the lines I added 
to indicate the changes - in practice the ** would be spaces)

     def GetBannedPattern(self, email):
         """Returns matched entry in ban_list if email matches.
         Otherwise returns None.
         """
         ban = False
         for pattern in self.ban_list:
             if pattern.startswith('^'):
                 # This is a regular expression match
                 try:
                     if re.search(pattern, email, re.IGNORECASE):
                         ban = True
                         break
                 except re.error:
                     # BAW: we should probably remove this pattern
                     pass
**          elif pattern.startswith('@'):
**              listname = self.internal_name()  # is this correct?
**              try:
**                  mname = pattern[1:].lower().strip()
**                  if mname == listname:
**                      # don't reference your own list
**                      syslog('error',
**                          'Ban_list listfor %s references own list',
**                          listname)
**                  else:
**                      mother = MailList(mname, lock=0)
**                      if mother.isMember(email):
**                          ban = True
**                          break
**              except Errors.MMUnknownListError:
**                  syslog('error',
**                      'Ban_list for list %s references non-existent 
list %s',
**                      listname, mname)
             else:
                 # Do the comparison case insensitively
                 if pattern.lower() == email.lower():
                     ban = True
                     break
         if ban:
             return pattern
         else:
             return None

Am I on the correct path?

Mark, if you have the time and/or inclination, could you explain your 
comments about

	Allowing @list_name in ban_list is a simple code modification if you
	don't care if various 'error' log messages such as list references
	itself or references non-existent list refer to
	'subscribe_auto_approval' even if the error is in ban_list.

Thanks to everyone for the help,
Chris



On 10/6/2015 5:43 PM, Mark Sapiro wrote:
> On 10/06/2015 08:07 AM, Chris Nulk wrote:
>> 1. The ban_list attribute is to help prevent unwanted people from
>> subscribing to a list, however, I want to restrict who can subscribe to
>> the list and ban anyone else.  I have the regex for who I want to allow
>> to subscribe but there isn't an allow_list attribute.  Is there an easy
>> way of allowing a regex to control who is able to subscribe?  Or, is
>> there a way to easily invert the regex logic and use it in ban_list?  As
>> an example (not the real regex), say I want to only allow @gmail.com to
>> subscribe to the list but no one else.
>
> As Aditya Jain replied, you can use Python RE negative lookahead
> assertions to create regexps with "doesn't match" conditions. See
> <https://docs.python.org/2/library/re.html#regular-expression-syntax>.
>
>
> Although the posted regexp modified for gmail
>
> ^[^@]+@(?!(.*\.)?gmail\.com$)
>
> will not match and hence allow, addresses like user at subdomain.gmail.com.
> To allow only '@gmail.com' addresses, e.g. to ban all non-'@gmail.com'
> addresses, use
>
> ^[^@]+@(?!gmail\.com$)
>
> Often, if you have the regexp to allow, the regexp to ban may be as
> simple as
>
> ^(?!the_allow_regexp)
>
>
>> 2. An additional requirement is to restrict a subgroup of the addresses
>> from subscribing.  In short, I want to allow all @gmail.com addresses to
>> subscribe except for a known subgroup.  Now the known subgroup is in a
>> Mailman list.  So, can I use a Mailman list in the ban_list attribute
>> similar to using a list in *_these_members attributes?  Or, would I have
>> to modify the code to allow using a Mailman list in the ban_list attribute?
>
> Allowing @list_name in ban_list is a simple code modification if you
> don't care if various 'error' log messages such as list references
> itself or references non-existent list refer to
> 'subscribe_auto_approval' even if the error is in ban_list.
>
> The change would be in this code in Mailman/Mail.List.py
>
>      def GetBannedPattern(self, email):
>          """Returns matched entry in ban_list if email matches.
>          Otherwise returns None.
>          """
>          return self.GetPattern(email, self.ban_list)
>
> change the last line to
>
>          return self.GetPattern(email, self.ban_list, at_list=True)
>
> Or, if you've installed the GLOBAL_BAN_LIST mod, make the change in each
> of the two lines in
>
>          return (self.GetPattern(email, self.ban_list) or
>                  self.GetPattern(email, mm_cfg.GLOBAL_BAN_LIST)
>                 )
>