Re: SPF question + patch (selective denial on SPF soft fail)

[Elliot Foster]

Chris Lewis wrote:
The rabid belief by some that RFC2142 mandated addresses MUST NOT be
filtered under any circumstances.  Including people who misinterpret SPF
records ;-)  [We publish ~all, some people interpret email .forwarded
thru something not in the SPF record to be forged and bounce it.]


On that subject, here's an old plugin that selectively rejects SPF soft 
failures.  I use it for paypal, ebay, banks, etc..  Basically, domains that I 
wish would publish hard -all SPF records.  Feedback welcome.

I need to clean up another plugin that does header checks for senders who have a 
valid SPF record, but the message header 'From' is one of the above domains.
#!/usr/bin/perl -Tw

sub hook_rcpt {
  my ($self, $transaction, $rcpt, %param) = @_;

  # special addresses don't get SPF-tested.
  return (DECLINED) if $self->qp->connection->relay_client();
  return DECLINED if $rcpt and $rcpt->user and $rcpt->user =~ 
/^(?:postmaster|abuse|mailer-daemon|root)$/i;

  my $sender = $transaction->sender;
  return (DECLINED) unless ($sender->format ne "<>");

  my @domains = $self->qp->config('forged_domains');
  my %forged_domains = map { $_ => 1  } @domains;

  my $host = '';
  my $fqdn = $sender->host;
  my @host = split /\./, $fqdn;
  while (@host >= 2) {
    $host = join '.', @host;
    if (defined($forged_domains{lc($host)})) {
      $host = $fqdn;
      last;
    }
    $host = '';
    shift(@host);
  }

  return (DECLINED) unless $host;

  my $result = $transaction->notes('spfresult');
  return (DECLINED) unless $result;

  if ($result eq "error") {
    return (DECLINED);
  }

  my $from = join '@', $sender->user, $sender->host;

  if ($result eq "softfail") {
    return (DENY, "I don't think you are allowed to send mail as '$from'.  Are 
you phishing?");
  }

#  if ($result eq "fail" and $self->{_args}{spf_deny}) {
#    return (DENY, "SPF forgery: $smtp_comment");
#  }

#  if ($result eq 'fail' or $result eq 'softfail') {
#    $self->log(LOGDEBUG, "result for $rcpt->address was $result: $comment");
#  }

  return DECLINED;
}