From 88fab6e0f3f5a650904908589a9cf9c867d766ec Mon Sep 17 00:00:00 2001
From: garvinhicking <garvinhicking>
Date: Wed, 11 Jan 2006 15:48:34 +0000
Subject: [PATCH] Implement suggestion by
 http://deep-resonance.org/2006/01/07/nochmal-trackbackspam-gegenmassnahmen

This is an experiment. I don't yet know if to trust this. It may get removed.
---
 .../lang_en.inc.php                           |  4 ++
 .../serendipity_event_spamblock.php           | 38 ++++++++++++++++++-
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/plugins/serendipity_event_spamblock/lang_en.inc.php b/plugins/serendipity_event_spamblock/lang_en.inc.php
index 45c4241..aea6dc2 100644
--- a/plugins/serendipity_event_spamblock/lang_en.inc.php
+++ b/plugins/serendipity_event_spamblock/lang_en.inc.php
@@ -92,4 +92,8 @@
 @define('PLUGIN_EVENT_SPAMBLOCK_REASON_TITLE', 'Entry title equals comment');
 @define('PLUGIN_EVENT_SPAMBLOCK_FILTER_TITLE', 'Reject comments which only contain the entry title');
 
+@define('PLUGIN_EVENT_SPAMBLOCK_TRACKBACKURL', 'Check Trackback URLs');
+@define('PLUGIN_EVENT_SPAMBLOCK_TRACKBACKURL_DESC', 'Only allow trackbacks, when its URL contains a link to your blog');
+@define('PLUGIN_EVENT_SPAMBLOCK_REASON_TRACKBACKURL', 'Trackback URL invalid.');
+
 ?>
diff --git a/plugins/serendipity_event_spamblock/serendipity_event_spamblock.php b/plugins/serendipity_event_spamblock/serendipity_event_spamblock.php
index 9881020..641f56d 100644
--- a/plugins/serendipity_event_spamblock/serendipity_event_spamblock.php
+++ b/plugins/serendipity_event_spamblock/serendipity_event_spamblock.php
@@ -34,7 +34,7 @@ var $filter_defaults;
             'smarty'      => '2.6.7',
             'php'         => '4.1.0'
         ));
-        $propbag->add('version',       '1.30');
+        $propbag->add('version',       '1.31');
         $propbag->add('event_hooks',    array(
             'frontend_saveComment' => true,
             'external_plugin'      => true,
@@ -43,7 +43,7 @@ var $filter_defaults;
             'backend_comments_top' => true,
             'backend_view_comment' => true
         ));
-        $propbag->add('configuration', array('killswitch', 'bodyclone', 'entrytitle', 'ipflood', 'captchas', 'captchas_ttl', 'captcha_color', 'forcemoderation', 'disable_api_comments', 'links_moderate', 'links_reject', 'contentfilter_activate', 'contentfilter_urls', 'bloggdeblacklist', 'contentfilter_authors', 'hide_email', 'checkmail', 'required_fields', 'logtype', 'logfile'));
+        $propbag->add('configuration', array('killswitch', 'bodyclone', 'entrytitle', 'ipflood', 'captchas', 'captchas_ttl', 'captcha_color', 'forcemoderation', 'disable_api_comments', 'trackback_check_url', 'links_moderate', 'links_reject', 'contentfilter_activate', 'contentfilter_urls', 'bloggdeblacklist', 'contentfilter_authors', 'hide_email', 'checkmail', 'required_fields', 'logtype', 'logfile'));
         $propbag->add('groups', array('ANTISPAM'));
 
         $this->filter_defaults = array(
@@ -71,6 +71,13 @@ var $filter_defaults;
 
                 break;
 
+            case 'trackback_check_url':
+                $propbag->add('type', 'boolean');
+                $propbag->add('name', PLUGIN_EVENT_SPAMBLOCK_TRACKBACKURL);
+                $propbag->add('description', PLUGIN_EVENT_SPAMBLOCK_TRACKBACKURL_DESC);
+                $propbag->add('default', false);
+                break;
+
             case 'hide_email':
                 $propbag->add('type', 'boolean');
                 $propbag->add('name', PLUGIN_EVENT_SPAMBLOCK_HIDE_EMAIL);
@@ -406,6 +413,33 @@ var $filter_defaults;
                             }
                             return false;
                         }
+                        
+                        // Check Trackback URLs?
+                        if ($addData['type'] == 'TRACKBACK' && serendipity_db_bool($this->get_config('trackback_check_url')) {
+                            require_once S9Y_PEAR_PATH . 'HTTP/Request.php';
+
+                            $req     = &new HTTP_Request($addData['url'], array('allowRedirects' => true, 'maxRedirects' => 5));
+                            $is_valid = false;
+                            if (PEAR::isError($req->sendRequest()) || $req->getResponseCode() != '200') {
+                                $is_valid = false;
+                            } else {
+                                $fdata = $req->getResponseBody();
+
+                                // Check if the target page contains a link to our blog
+                                if (preg_match('@' . preg_quote($serendipity['baseURL'], '@') . '@i', $fdata)) {
+                                    $is_valid = true;
+                                } else {
+                                    $is_valid = false;
+                                }
+                            }
+
+                            if ($is_valid === false) {
+                                $this->log($logfile, $eventData['id'], 'REJECTED', PLUGIN_EVENT_SPAMBLOCK_REASON_TRACKBACKURL, $addData);
+                                $eventData = array('allow_comments' => false);
+                                $serendipity['messagestack']['comments'][] = PLUGIN_EVENT_SPAMBLOCK_REASON_TRACKBACKURL;
+                                return false;
+                            }
+                        }
 
                         // Check for word filtering
                         if ($filter_type = $this->get_config('contentfilter_activate', 'moderate')) {
-- 
2.39.5