File indexing completed on 2024-05-12 05:58:46

 <?php
 
 /**
  *  ocs-webserver
  *
  *  Copyright 2016 by pling GmbH.
  *
  *    This file is part of ocs-webserver.
  *
  *    This program is free software: you can redistribute it and/or modify
  *    it under the terms of the GNU Affero General Public License as
  *    published by the Free Software Foundation, either version 3 of the
  *    License, or (at your option) any later version.
  *
  *    This program is distributed in the hope that it will be useful,
  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *    GNU Affero General Public License for more details.
  *
  *    You should have received a copy of the GNU Affero General Public License
  *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  **/
 class Default_Model_CsrfProtection
 {
     const validity = 3600;
 
     /**
      * @param Zend_Form $form
      * @param string    $csrf_salt_name
      * @param string    $field_name
      *
      * @return Zend_Form_Element
      * @throws Zend_Form_Exception
      * @throws Zend_Session_Exception
      */
     public static function createCsrf($form, $csrf_salt_name, $field_name = "csrf")
     {
         /** @var Zend_Form_Element_Hash $element */
         $element = $form->createElement('hash', $field_name, array(
             'salt' => $csrf_salt_name
         ));
         //Create unique ID if you need to use some Javascript on the CSRF Element
         $element->setAttrib('id', $form->getName() . '_' . $element->getId());
         $element->setDecorators(array('ViewHelper'));
         $element->setSession(new Zend_Session_Namespace('login_csrf'));
         $form->addElement($element);
 
         return $element;
     }
 
     /**
      * @param $hash
      *
      * @return bool
      * @throws Zend_Exception
      * @throws Zend_Session_Exception
      */
     public static function validateCsrfToken($hash)
     {
         $session = new Zend_Session_Namespace();
 
         if (false === function_exists("hash_equals")) {
             $valid = self::hash_equals($session->crsf_token, $hash);
             Zend_Registry::get('logger')->debug(__METHOD__
                 . PHP_EOL . ' - session csrf token: ' . print_r($session->crsf_token, true)
                 . PHP_EOL . ' - form csrf token: ' . print_r($hash, true)
                 . PHP_EOL . ' - crsf validation result: ' . (($valid === true) ? 'true' : 'false'));
 
             return $valid;
         }
 
         if (empty($session->crsf_token)) {
             return false;
         }
         $valid = hash_equals($session->crsf_token, $hash);
         Zend_Registry::get('logger')->debug(__METHOD__
                 . PHP_EOL . ' - session csrf token: ' . print_r($session->crsf_token, true)
                 . PHP_EOL . ' - form csrf token: ' . print_r($hash, true)
                 . PHP_EOL . ' - crsf validation result: ' . (($valid === true) ? 'true' : 'false'));
 
         return $valid;
     }
 
     /**
      * @param $a
      * @param $b
      *
      * @return bool
      * @author http://php.net/manual/en/function.hash-equals.php#usernotes  Cedric Van Bockhaven
      */
     private static function hash_equals($a, $b)
     {
         $ret = strlen($a) ^ strlen($b);
         $ret |= array_sum(unpack("C*", $a ^ $b));
 
         return !$ret;
     }
 
     /**
      * @return Zend_Form_Element_Hidden
      * @throws Zend_Form_Exception
      * @throws Zend_Session_Exception
      */
     public static function getFormCsrf($name = 'crsf_token')
     {
         $form_crsf = new Zend_Form_Element_Hidden($name);
         $form_crsf->setFilters(array('StringTrim'));
         $form_crsf->setRequired(true);
         $form_crsf->setDecorators(array('ViewHelper'));
         $form_crsf->setValue(self::getCsrfToken());
 
         return $form_crsf;
     }
 
     /**
      * @return mixed|string
      * @throws Zend_Session_Exception
      */
     public static function getCsrfToken()
     {
         $session = new Zend_Session_Namespace();
         if ($session->crsf_token AND $session->crsf_expire AND ($session->crsf_expire > microtime(true))) {
             return $session->crsf_token;
         }
         $session->crsf_expire = microtime(true) + self::validity;
         if (function_exists('mcrypt_create_iv')) {
             $session->crsf_token = bin2hex(mcrypt_create_iv(32, MCRYPT_DEV_URANDOM));
         } else {
             $session->crsf_token = bin2hex(openssl_random_pseudo_bytes(32));
         }
 
         return $session->crsf_token;
     }
 
 }