Postfix maildir policy server.

maildirquota-policy.pl

#!/usr/bin/perl

##############################################
# Postfix policy server                      #
# postfix-policyd-quota                      #
# v1.01                                      #
# by Michael Garvin <gar@comrade.us>         #
# Queries user's maildirquota, and rejects   #
#  if they are over.  Takes no action        #
#  (DUNNO) otherwise.                        #
# Must be able to read ~/Maildir/maildirsize #
#                                            #
# borrowed heavily from postfix-policy-spf   #
# see http://spf.pobox.com/ for original     #
##############################################


#12/30/2004 1.0
#   Initial Release
#1/03/2004 1.01
#   Added verbose condition checking to syslog statements
#   Added explicit close to MAILDIRQUOTA on else to $quota > 0
#   Changed syslog level "warn" to "warning" in places, as "warn" is invalid
#1/10/2004 1.1
#	Decided to include the recipient_map lookup code in the publicly
#		available source

use Fcntl;
use Sys::Syslog qw(:DEFAULT setlogsock);
use strict;
$ENV{PATH} = "/bin:/usr/sbin"; #suid protection

# ----------------------------------------------------------
# 		       configuration
# ----------------------------------------------------------

  my @HANDLERS;
  push @HANDLERS, "maildirquota_check";

my $VERBOSE = 0;

my $DEFAULT_RESPONSE = "DUNNO";

#
# Syslogging options for verbose mode and for fatal errors.
# NOTE: comment out the $syslog_socktype line if syslogging does not
# work on your system.
#

my $syslog_socktype = 'unix'; # inet, unix, stream, console
my $syslog_facility = "mail";
my $syslog_options  = "pid";
my $syslog_priority = "info";
my $syslog_ident    = "postfix/policy-quota";

# ----------------------------------------------------------
#		   minimal documentation
# ----------------------------------------------------------

#
# Usage: quota-policy.pl [-v]
#
# Demo delegated Postfix SMTPD policy server.
# This server implements Maildirquota.
# Another server implements greylisting.
# Another server implements SPF.
# Postfix has a pluggable policy server architecture.
# You can call one or both from Postfix.
# 
# This documentation assumes you have read Postfix's README_FILES/SMTPD_POLICY_README
# 
# Logging is sent to syslogd.
#
# How it works: each time a Postfix SMTP server process is started
# it connects to the policy service socket, and Postfix runs one
# instance of this PERL script.  By default, a Postfix SMTP server
# process terminates after 100 seconds of idle time, or after serving
# 100 clients. Thus, the cost of starting this PERL script is smoothed
# out over time.
#
# To run this from /etc/postfix/master.cf:
#
#    policy  unix  -       n       n       -       -       spawn
#      user=nobody argv=/usr/bin/perl /usr/libexec/postfix/smtpd-policy.pl
#
# To use this from Postfix SMTPD, use in /etc/postfix/main.cf:
#
#    smtpd_recipient_restrictions =
#	...
#	reject_unauth_destination
#	check_policy_service unix:private/policy
#	...
#
# NOTE: specify check_policy_service AFTER reject_unauth_destination
# or else your system can become an open relay.
#
# To test this script by hand, execute:
#
#    % perl smtpd-policy.pl
#
# Each query is a bunch of attributes. Order does not matter, and
# the demo script uses only a few of all the attributes shown below:
#
#    request=smtpd_access_policy
#    protocol_state=RCPT
#    protocol_name=SMTP
#    helo_name=some.domain.tld
#    queue_id=8045F2AB23
#    sender=foo@bar.tld
#    recipient=bar@foo.tld
#    client_address=1.2.3.4
#    client_name=another.domain.tld
#    [empty line]
#
# The policy server script will answer in the same style, with an
# attribute list followed by a empty line:
#
#    action=dunno
#    [empty line]
#

# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: client_address=208.210.125.227
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: client_name=newbabe.mengwong.com
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: helo_name=newbabe.mengwong.com
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: protocol_name=ESMTP
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: protocol_state=RCPT
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: queue_id=
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: recipient=mengwong@dumbo.pobox.com
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: request=smtpd_access_policy
# Jul 23 18:43:29 dumbo/dumbo policyd[21171]: Attribute: sender=mengwong@newbabe.mengwong.com

# ----------------------------------------------------------
# 		       initialization
# ----------------------------------------------------------

#
# Log an error and abort.
#
sub fatal_exit {
  syslog(err  => "fatal_exit: @_");
  syslog(warning => "fatal_exit: @_");
  syslog(info => "fatal_exit: @_");
  die "fatal: @_";
}

#
# Unbuffer standard output.
#
select((select(STDOUT), $| = 1)[0]);

#
# This process runs as a daemon, so it can't log to a terminal. Use
# syslog so that people can actually see our messages.
#
setlogsock $syslog_socktype;
openlog $syslog_ident, $syslog_options, $syslog_facility;

# ----------------------------------------------------------
# 			    main
# ----------------------------------------------------------

#
# Receive a bunch of attributes, evaluate the policy, send the result.
#
my %attr;
while (<STDIN>) {
  chomp;
  if (/=/)       { my ($k, $v) = split (/=/, $_, 2); $attr{$k} = $v; next }
  elsif (length) { syslog(warning=>sprintf("warning: ignoring garbage: %.100s", $_)); next; }

  if ($VERBOSE) {
    for (sort keys %attr) {
      syslog(debug=> "Attribute: %s=%s", $_, $attr{$_});
    }
  }

  fatal_exit ("unrecognized request type: '$attr{request}'") unless $attr{request} eq "smtpd_access_policy";

  my $action = $DEFAULT_RESPONSE;
  my %responses;
  foreach my $handler (@HANDLERS) {
    no strict 'refs';
    my $response = $handler->(attr=>\%attr);
    if ($VERBOSE) {
      syslog(debug=> "handler %s: %s", $handler, $response);
    }
    if ($response and $response !~ /^dunno/i) {
      syslog(info=> "handler %s: %s is decisive.", $handler, $response);
      $action = $response; last;
    }
  }

  if ($VERBOSE) {
    syslog(info=> "decided action=%s", $action);
  }

  #THIS IS THE ACTUAL ACTION GETTING REPORTED TO POSTFIX
  print STDOUT "action=$action\n\n";
  %attr = ();
}

# ----------------------------------------------------------
# 		      plugin: maildirquota
# ----------------------------------------------------------
sub maildirquota_check {
  local %_ = @_;
  my %attr = %{ $_{attr} };
  my ($smtp_comment,$header_comment,$result,$lookup_loop,$lookup_result);
  my $local_hostname = "mail.comrade.us";

  if ($attr{recipient}) {
    if ($attr{recipient} =~ /^([A-Za-z0-9@._\-]+)$/) { 	
      $attr{recipient} = $1; 			# $data now untainted
    } else {
      syslog(warning=> "Bad data in %s", $attr{recipient});
      return "DUNNO";
    }
  } else {
    return "DUNNO";
  }

  chomp $attr{recipient};
  my $recipient = $attr{recipient};

  #this loop is a primitive attempt at doing recipient lookups.
  #you'll probably want to chuck it for your own code
#  while ($lookup_loop != 1) {

    #put all your virtual_alias_maps, etc here
    my @MAPS;
    push @MAPS, "ldap:ldapvirtual";

    my @MAPS_CA = @MAPS;
  
    foreach my $map (@MAPS) {
      if ($VERBOSE) { syslog(info=> "looking up %s with %s", $recipient, $map); }
      $lookup_result = `/usr/sbin/postmap -c /etc/postfix -q $recipient $map`;
      if ($VERBOSE) { syslog(info=> "found %s", $lookup_result); }
      if ($lookup_result) { $recipient = $lookup_result; }
      chomp $recipient;
    }
    $recipient =~ /[^@]+@(.*)/;
    my $domain = $1;
    if ($attr{recipient} == $recipient) {
      foreach my $map (@MAPS_CA) {
        if ($VERBOSE) { syslog(info=> "looking up @%s with %s", $domain, $map); }
        $lookup_result = `postmap -c /etc/postfix -q \@$domain $map`;
        if ($lookup_result) { $recipient = $lookup_result; }
        chomp $recipient;
      }
    }
    if ($recipient =~ /([^@]+)\@$local_hostname/) {
		$recipient=$1;
#        $lookup_loop=1;
#    } elsif ($attr{recipient} == $recipient) {
#        if ($VERBOSE) { syslog(info=> "Asked to lookup non-local %s", $recipient); }
#        $lookup_loop=1;
#        return "DUNNO";
    }
#  }
  $attr{recipient}=$recipient;
  if (my ($name, $passwd, $uid, $gid, $quota, $comment, $gcos, $homedir, $shell) = getpwnam($attr{recipient})) {
	open (MAILDIRSIZE, $homedir."/Maildir/maildirsize");
	my $quota = <MAILDIRSIZE>;
	$quota =~ s/[^0-9]//;
	chomp $quota;
	if ($quota > 0) {
		my ($used,$entry);
		while ($entry = <MAILDIRSIZE>) {
			$entry =~ s/^[[:space:]]*//;
			my @entry = split ("[[:space:]]+",$entry);
			$used += $entry[0];
		}
		close MAILDIRSIZE;
		if ($used > $quota) {
			$result = "fail"; $smtp_comment = "User over quota";
		} else {
			$used += $attr{size};
			if ($used > $quota) {
				$result = "fail"; $smtp_comment = "Message would put user over quota";
			} else {
				$result = "pass";
			}
		}
	} else {
		close MAILDIRSIZE;
	}
  }

  if    ($result eq "pass")  { return "DUNNO"; }
  elsif ($result eq "fail")  { return "REJECT " . ($smtp_comment || $header_comment); }
  elsif ($result eq "error") { return "450 temporary failure: $smtp_comment"; }
  else                       { return "DUNNO"; }
  # unknown, softfail, and none all return DUNNO

}