CRM/Core/Key.php

   1 <?php
   2 /*
   3  +--------------------------------------------------------------------+
   4  | CiviCRM version 4.6                                                |
   5  +--------------------------------------------------------------------+
   6  | Copyright CiviCRM LLC (c) 2004-2014                                |
   7  +--------------------------------------------------------------------+
   8  | This file is a part of CiviCRM.                                    |
   9  |                                                                    |
  10  | CiviCRM is free software; you can copy, modify, and distribute it  |
  11  | under the terms of the GNU Affero General Public License           |
  12  | Version 3, 19 November 2007 and the CiviCRM Licensing Exception.   |
  13  |                                                                    |
  14  | CiviCRM is distributed in the hope that it will be useful, but     |
  15  | WITHOUT ANY WARRANTY; without even the implied warranty of         |
  16  | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.               |
  17  | See the GNU Affero General Public License for more details.        |
  18  |                                                                    |
  19  | You should have received a copy of the GNU Affero General Public   |
  20  | License and the CiviCRM Licensing Exception along                  |
  21  | with this program; if not, contact CiviCRM LLC                     |
  22  | at info[AT]civicrm[DOT]org. If you have questions about the        |
  23  | GNU Affero General Public License or the licensing of CiviCRM,     |
  24  | see the CiviCRM license FAQ at http://civicrm.org/licensing        |
  25  +--------------------------------------------------------------------+
  26 */
  27
  28 /**
  29  *
  30  * @package CRM
  31  * @copyright CiviCRM LLC (c) 2004-2014
  32  * $Id$
  33  *
  34  */
  35 class CRM_Core_Key {
  36   static $_key = NULL;
  37
  38   static $_sessionID = NULL;
  39
  40   /**
  41    * Generate a private key per session and store in session
  42    *
  43    * @return string private key for this session
  44    * @static
  45    */
  46   public static function privateKey() {
  47     if (!self::$_key) {
  48       $session = CRM_Core_Session::singleton();
  49       self::$_key = $session->get('qfPrivateKey');
  50       if (!self::$_key) {
  51         self::$_key = md5(uniqid(mt_rand(), TRUE)) . md5(uniqid(mt_rand(), TRUE));
  52         $session->set('qfPrivateKey', self::$_key);
  53       }
  54     }
  55     return self::$_key;
  56   }
  57
  58   /**
  59    * @return mixed|null|string
  60    */
  61   public static function sessionID() {
  62     if (!self::$_sessionID) {
  63       $session = CRM_Core_Session::singleton();
  64       self::$_sessionID = $session->get('qfSessionID');
  65       if (!self::$_sessionID) {
  66         self::$_sessionID = session_id();
  67         $session->set('qfSessionID', self::$_sessionID);
  68       }
  69     }
  70     return self::$_sessionID;
  71   }
  72
  73   /**
  74    * Generate a form key based on form name, the current user session
  75    * and a private key. Modelled after drupal's form API
  76    *
  77    * @param string $name
  78    * @param bool $addSequence should we add a unique sequence number to the end of the key
  79    *
  80    * @return string       valid formID
  81    * @static
  82    */
  83   public static function get($name, $addSequence = FALSE) {
  84     $privateKey = self::privateKey();
  85     $sessionID  = self::sessionID();
  86     $key        = md5($sessionID . $name . $privateKey);
  87
  88     if ($addSequence) {
  89       // now generate a random number between 1 and 100K and add it to the key
  90       // so that we can have forms in mutiple tabs etc
  91       $key = $key . '_' . mt_rand(1, 10000);
  92     }
  93     return $key;
  94   }
  95
  96   /**
  97    * Validate a form key based on the form name
  98    *
  99    * @param string $key
 100    * @param string $name
 101    * @param bool $addSequence
 102    *
 103    * @return string $formKey if valid, else null
 104    * @static
 105    */
 106   public static function validate($key, $name, $addSequence = FALSE) {
 107     if (!is_string($key)) {
 108       return NULL;
 109     }
 110
 111     if ($addSequence) {
 112       list($k, $t) = explode('_', $key);
 113       if ($t < 1 || $t > 10000) {
 114         return NULL;
 115       }
 116     }
 117     else {
 118       $k = $key;
 119     }
 120
 121     $privateKey = self::privateKey();
 122     $sessionID = self::sessionID();
 123     if ($k != md5($sessionID . $name . $privateKey)) {
 124       return NULL;
 125     }
 126     return $key;
 127   }
 128
 129   /**
 130    * @param $key
 131    *
 132    * @return bool
 133    */
 134   public static function valid($key) {
 135     // a valid key is a 32 digit hex number
 136     // followed by an optional _ and a number between 1 and 10000
 137     if (strpos('_', $key) !== FALSE) {
 138       list($hash, $seq) = explode('_', $key);
 139
 140       // ensure seq is between 1 and 10000
 141       if (!is_numeric($seq) ||
 142         $seq < 1 ||
 143         $seq > 10000
 144       ) {
 145         return FALSE;
 146       }
 147     }
 148     else {
 149       $hash = $key;
 150     }
 151
 152     // ensure that hash is a 32 digit hex number
 153     return preg_match('#[0-9a-f]{32}#i', $hash) ? TRUE : FALSE;
 154   }
 155 }