Script to list mailboxes, useful for PAM auth

[D G Teed <donald.teed@xxxxxxxxx>]

I didn't see many living examples of how to do this, so I thought
it might be useful to share.

In our system, we have an LDAP auth backend which can be broader
than the mailboxes on a system.  We didn't have any luck with
using pam_groupdn in pam_ldap.conf, so it is useful to use the PAM
module listfile.  In pam.d/imap (same for pop or sieve) we would include:

auth        required      pam_listfile.so  item=user sense=allow file=/cyrus/mailmgmt/mysystemlist

If you are not in this file list of users, but you have
authenticated against the backend OK, you won't get in.

Keeping that list of mailbox users updated is done by
a cron running the perl script following:


#!/usr/bin/perl -w

# Maintain a list of valid mailboxes on mysystem for pam authentication purposes

use strict;
use Fcntl ':flock';

# Global variables for filenames, etc.
my( $basedir );
$basedir = "/cyrus/mailmgmt";

my( $PWD ) = $ENV{'PWD'};

chdir ( $basedir );

# Other global variables
my( %mysystemboxes, $now);

# Get the mailbox list from mysystem
%mysystemboxes = &get_mysystem_mailboxes( );

chdir( $PWD ) if ( $PWD );

exit 0;

#
# It's all subroutines from here on out
#
#
#
# Subroutine to get the mailbox list from mysystem.
#

sub get_mysystem_mailboxes( ) {
   my( @mysystemboxes );
   # Get the list of mailboxes from mysystem.example.com
   @mysystemboxes = &get_mailbox_list( "localhost", "cyrusadm", "mypassword" );
   if( grep { /^IMAP error:/ } @mysystemboxes ) {
      die "Error retrieving mailbox list from mysystem.\n@mysystemboxes\n";
   }
   # Dump the mailbox list to a file
   open( SYSTEMBOXES, "> $basedir/mysystemlist " ) or die "Couldn't open file: $!\n";
   foreach( @mysystemboxes ) { print SYSTEMBOXES "$_\n"; }
   print SYSTEMBOXES "cyrusadm\n";
   close( SYSTEMBOXES ) or die "Couldn't close file: $!\n";
   return %{ { map { $_ => 1 } @mysystemboxes } };
}
#
#
# Subroutine for an IMAP connection to get a mailbox list from a server
#
sub get_mailbox_list( $$$ ) {
   use IMAP::Admin;

   my( $server, $uid, $pwd ) = @_;
   my( $client, $mailbox, @mailboxlist, @usernames, $username );

   $client = IMAP::Admin->new(     'Server'=>      "$server",
                                   'Login' =>      "$uid",
                                   'Password' =>   "$pwd",
                                   'CRAM'  =>      0
                                   ) or
        return "Couldn't create IMAP connection: $!\n";

   @mailboxlist = $client->list( "user.*" ) or
        return "IMAP error: \n\t" . $client->error . "\n";

   $client->close;
  foreach $mailbox ( @mailboxlist ) {
      push @usernames, ${ [ split( /\./, $mailbox ) ] }[1];
   }

   @usernames = keys %{ { map { $_ => 1 } @usernames } };

   return( @usernames );
}


It would need some adjustment for different type of authentication or
separator.


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