lib/Mail/SpamAssassin/Plugin/HTTPSMismatch.pm

# <@LICENSE>
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to you under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at:
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# </@LICENSE>

package Mail::SpamAssassin::Plugin::HTTPSMismatch;

use Mail::SpamAssassin::Plugin;
use Mail::SpamAssassin::Logger;
use Mail::SpamAssassin::Constants qw(:ip);
use strict;
use warnings;
# use bytes;
use re 'taint';

our @ISA = qw(Mail::SpamAssassin::Plugin);

# constructor: register the eval rule
sub new {
  my $class = shift;
  my $mailsaobject = shift;

  # some boilerplate...
  $class = ref($class) || $class;
  my $self = $class->SUPER::new($mailsaobject);
  bless ($self, $class);

  # the important bit!
  $self->register_eval_rule ("check_https_http_mismatch", $Mail::SpamAssassin::Conf::TYPE_BODY_EVALS);

  return $self;
}

# [lt]a href="http://baboz-njeryz.de/"[gt]https://bankofamerica.com/[lt]/a[gt]
# ("<" and ">" replaced with "[lt]" and "[gt]" to avoid Kaspersky Desktop AV
# false positive ;)
sub check_https_http_mismatch {
  my ($self, $pms, undef, $minanchors, $maxanchors) = @_;

  $minanchors ||= 1;

  foreach my $html (@{$pms->{html_all}}) {
    my $hit = 0;
    my $anchors = 0;
    foreach my $k (keys %{$html->{uri_detail}}) {
      my $v = $html->{uri_detail}->{$k};

      # if the URI wasn't used for an anchor tag, or the anchor text didn't
      # exist, skip this.
      next unless exists $v->{anchor_text} && @{$v->{anchor_text}};

      my $uri;
      if ($k =~ m@^https?://([^/:?#]+)@i) {
        $uri = $1;
        # Skip IPs since there's another rule to catch that already
        if ($uri =~ IS_IP_ADDRESS) {
          $uri = undef;
          next;
        } 
        # want to compare whole hostnames instead of domains?
        # comment this next section to the blank line.
        $uri = $self->{main}->{registryboundaries}->trim_domain($uri);
        my $domain = $self->{main}->{registryboundaries}->uri_to_domain($uri);
        $uri = undef  unless $self->{main}->{registryboundaries}->is_domain_valid($domain);
      }
      next unless $uri;

      $anchors++ if exists $v->{anchor_text};
      foreach (@{$v->{anchor_text}}) {
        if (m@https://([^\s/:?#]+)@i) {
          my $https = $1;

	  # want to compare whole hostnames instead of domains?
	  # comment this next section to the blank line.
          if ($https !~ IS_IP_ADDRESS) {
	    $https = $self->{main}->{registryboundaries}->trim_domain($https);
            $https = undef  unless $self->{main}->{registryboundaries}->is_domain_valid($https);
          }
	  next unless $https;
	  dbg("https_http_mismatch: domains $uri -> $https");
	  next if $uri eq $https;
	  $hit = 1;
	  last;
        }
      }
    }

    dbg("https_http_mismatch: anchors $anchors");
    return 1 if $hit && $anchors >= $minanchors &&
                (!defined $maxanchors || $anchors < $maxanchors);
  }

  return 0;
}

1;