From be41e4e5189e6107e05a18f69eae3c4b2dfb8604 Mon Sep 17 00:00:00 2001
From: Jeff Webster <jsw@ncsu.edu>
Date: Sun, 4 Mar 2018 01:07:37 -0500
Subject: [PATCH] MDL-48501 form/recaptcha: update to use reCAPTCHA v2

---
 lib/form/recaptcha.php | 78 +++++++++---------------------------------
 1 file changed, 16 insertions(+), 62 deletions(-)

diff --git a/lib/form/recaptcha.php b/lib/form/recaptcha.php
index 87b3d2a8a8d..2eb732624e8 100644
--- a/lib/form/recaptcha.php
+++ b/lib/form/recaptcha.php
@@ -46,9 +46,6 @@ class MoodleQuickForm_recaptcha extends HTML_QuickForm_input implements templata
     /** @var string html for help button, if empty then no help */
     var $_helpbutton='';
 
-    /** @var bool if true, recaptcha will be servered from https */
-    var $_https=false;
-
     /**
      * constructor
      *
@@ -58,14 +55,8 @@ class MoodleQuickForm_recaptcha extends HTML_QuickForm_input implements templata
      *              or an associative array
      */
     public function __construct($elementName = null, $elementLabel = null, $attributes = null) {
-        global $CFG;
         parent::__construct($elementName, $elementLabel, $attributes);
         $this->_type = 'recaptcha';
-        if (is_https()) {
-            $this->_https = true;
-        } else {
-            $this->_https = false;
-        }
     }
 
     /**
@@ -79,49 +70,15 @@ class MoodleQuickForm_recaptcha extends HTML_QuickForm_input implements templata
     }
 
     /**
-     * Returns the recaptcha element in HTML
+     * Returns the reCAPTCHA element in HTML
      *
-     * @return string
+     * @return string The HTML to render
      */
-    function toHtml() {
-        global $CFG, $PAGE;
-        require_once $CFG->libdir . '/recaptchalib.php';
+    public function toHtml() {
+        global $CFG;
+        require_once($CFG->libdir . '/recaptchalib_v2.php');
 
-        $recaptureoptions = Array('theme'=>'custom', 'custom_theme_widget'=>'recaptcha_widget');
-        $html = html_writer::script(js_writer::set_variable('RecaptchaOptions', $recaptureoptions));
-
-        $attributes = $this->getAttributes();
-        if (empty($attributes['error_message'])) {
-            $attributes['error_message'] = null;
-            $this->setAttributes($attributes);
-        }
-        $error = $attributes['error_message'];
-        unset($attributes['error_message']);
-
-        $strincorrectpleasetryagain = get_string('incorrectpleasetryagain', 'auth');
-        $strenterthewordsabove = get_string('enterthewordsabove', 'auth');
-        $strenterthenumbersyouhear = get_string('enterthenumbersyouhear', 'auth');
-        $strgetanothercaptcha = get_string('getanothercaptcha', 'auth');
-        $strgetanaudiocaptcha = get_string('getanaudiocaptcha', 'auth');
-        $strgetanimagecaptcha = get_string('getanimagecaptcha', 'auth');
-
-        $html .= '
-<div id="recaptcha_widget" style="display:none">
-
-<div id="recaptcha_image"></div>
-<div class="recaptcha_only_if_incorrect_sol" style="color:red">' . $strincorrectpleasetryagain . '</div>
-
-<span class="recaptcha_only_if_image"><label for="recaptcha_response_field">' . $strenterthewordsabove . '</label></span>
-<span class="recaptcha_only_if_audio"><label for="recaptcha_response_field">' . $strenterthenumbersyouhear . '</label></span>
-
-<input type="text" id="recaptcha_response_field" name="recaptcha_response_field" class="text-ltr" />
-<input type="hidden" name="recaptcha_element" value="dummyvalue" /> <!-- Dummy value to fool formslib -->
-<div><a href="javascript:Recaptcha.reload()">' . $strgetanothercaptcha . '</a></div>
-<div class="recaptcha_only_if_image"><a href="javascript:Recaptcha.switch_type(\'audio\')">' . $strgetanaudiocaptcha . '</a></div>
-<div class="recaptcha_only_if_audio"><a href="javascript:Recaptcha.switch_type(\'image\')">' . $strgetanimagecaptcha . '</a></div>
-</div>';
-
-        return $html . recaptcha_get_html($CFG->recaptchapublickey, $error, $this->_https);
+        return recaptcha_get_challenge_html(RECAPTCHA_API_URL, $CFG->recaptchapublickey);
     }
 
     /**
@@ -134,25 +91,22 @@ class MoodleQuickForm_recaptcha extends HTML_QuickForm_input implements templata
     }
 
     /**
-     * Checks input and challenged field
+     * Checks recaptcha response with Google.
      *
-     * @param string $challenge_field recaptcha shown  to user
-     * @param string $response_field input value by user
+     * @param string $responsestr
      * @return bool
      */
-    function verify($challenge_field, $response_field) {
+    public function verify($responsestr) {
         global $CFG;
-        require_once $CFG->libdir . '/recaptchalib.php';
-        $response = recaptcha_check_answer($CFG->recaptchaprivatekey,
-                                           getremoteaddr(),
-                                           $challenge_field,
-                                           $response_field,
-                                           $this->_https);
-        if (!$response->is_valid) {
+        require_once($CFG->libdir . '/recaptchalib_v2.php');
+
+        $response = recaptcha_check_response(RECAPTCHA_VERIFY_URL, $CFG->recaptchaprivatekey,
+                                           getremoteaddr(), $responsestr);
+        if (!$response['isvalid']) {
             $attributes = $this->getAttributes();
-            $attributes['error_message'] = $response->error;
+            $attributes['error_message'] = $response['error'];
             $this->setAttributes($attributes);
-            return $response->error;
+            return $response['error'];
         }
         return true;
     }