<?php
/**
* This file contains classes implementing security manager feature.
*
* @author Qiang Xue <[email protected]>
* @link http://www.yiiframework.com/
* @copyright Copyright © 2008-2011 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
/**
* CSecurityManager provides private keys, hashing and encryption functions.
*
* CSecurityManager is used by Yii components and applications for security-related purpose.
* For example, it is used in cookie validation feature to prevent cookie data
* from being tampered.
*
* CSecurityManager is mainly used to protect data from being tampered and viewed.
* It can generate HMAC and encrypt the data. The private key used to generate HMAC
* is set by {@link setValidationKey ValidationKey}. The key used to encrypt data is
* specified by {@link setEncryptionKey EncryptionKey}. If the above keys are not
* explicitly set, random keys will be generated and used.
*
* To protected data with HMAC, call {@link hashData()}; and to check if the data
* is tampered, call {@link validateData()}, which will return the real data if
* it is not tampered. The algorithm used to generated HMAC is specified by
* {@link validation}.
*
* To encrypt and decrypt data, call {@link encrypt()} and {@link decrypt()}
* respectively, which uses 3DES encryption algorithm. Note, the PHP Mcrypt
* extension must be installed and loaded.
*
* CSecurityManager is a core application component that can be accessed via
* {@link CApplication::getSecurityManager()}.
*
* @author Qiang Xue <[email protected]>
* @version $Id: CSecurityManager.php 3204 2011-05-05 21:36:32Z alexander.makarow $
* @package system.base
* @since 1.0
*/
class CSecurityManager extends CApplicationComponent
{
const STATE_VALIDATION_KEY='Yii.CSecurityManager.validationkey';
const STATE_ENCRYPTION_KEY='Yii.CSecurityManager.encryptionkey';
/**
* @var string the name of the hashing algorithm to be used by {@link computeHMAC}.
* See {@link http://php.net/manual/en/function.hash-algos.php hash-algos} for the list of possible
* hash algorithms. Note that if you are using PHP 5.1.1 or below, you can only use 'sha1' or 'md5'.
*
* Defaults to 'sha1', meaning using SHA1 hash algorithm.
* @since 1.1.3
*/
public $hashAlgorithm='sha1';
/**
* @var mixed the name of the crypt algorithm to be used by {@link encrypt} and {@link decrypt}.
* This will be passed as the first parameter to {@link http://php.net/manual/en/function.mcrypt-module-open.php mcrypt_module_open}.
*
* This property can also be configured as an array. In this case, the array elements will be passed in order
* as parameters to mcrypt_module_open. For example, <code>array('rijndael-256', '', 'ofb', '')</code>.
*
* Defaults to 'des', meaning using DES crypt algorithm.
* @since 1.1.3
*/
public $cryptAlgorithm='des';
private $_validationKey;
private $_encryptionKey;
/**
* @return string a randomly generated private key
*/
protected function generateRandomKey()
{
return sprintf('%08x%08x%08x%08x',mt_rand(),mt_rand(),mt_rand(),mt_rand());
}
/**
* @return string the private key used to generate HMAC.
* If the key is not explicitly set, a random one is generated and returned.
*/
public function getValidationKey()
{
if($this->_validationKey!==null)
return $this->_validationKey;
else
{
if(($key=Yii::app()->getGlobalState(self::STATE_VALIDATION_KEY))!==null)
$this->setValidationKey($key);
else
{
$key=$this->generateRandomKey();
$this->setValidationKey($key);
Yii::app()->setGlobalState(self::STATE_VALIDATION_KEY,$key);
}
return $this->_validationKey;
}
}
/**
* @param string $value the key used to generate HMAC
* @throws CException if the key is empty
*/
public function setValidationKey($value)
{
if(!empty($value))
$this->_validationKey=$value;
else
throw new CException(Yii::t('yii','CSecurityManager.validationKey cannot be empty.'));
}
/**
* @return string the private key used to encrypt/decrypt data.
* If the key is not explicitly set, a random one is generated and returned.
*/
public function getEncryptionKey()
{
if($this->_encryptionKey!==null)
return $this->_encryptionKey;
else
{
if(($key=Yii::app()->getGlobalState(self::STATE_ENCRYPTION_KEY))!==null)
$this->setEncryptionKey($key);
else
{
$key=$this->generateRandomKey();
$this->setEncryptionKey($key);
Yii::app()->setGlobalState(self::STATE_ENCRYPTION_KEY,$key);
}
return $this->_encryptionKey;
}
}
/**
* @param string $value the key used to encrypt/decrypt data.
* @throws CException if the key is empty
*/
public function setEncryptionKey($value)
{
if(!empty($value))
$this->_encryptionKey=$value;
else
throw new CException(Yii::t('yii','CSecurityManager.encryptionKey cannot be empty.'));
}
/**
* This method has been deprecated since version 1.1.3.
* Please use {@link hashAlgorithm} instead.
* @return string
*/
public function getValidation()
{
return $this->hashAlgorithm;
}
/**
* This method has been deprecated since version 1.1.3.
* Please use {@link hashAlgorithm} instead.
* @param string $value -
*/
public function setValidation($value)
{
$this->hashAlgorithm=$value;
}
/**
* Encrypts data.
* @param string $data data to be encrypted.
* @param string $key the decryption key. This defaults to null, meaning using {@link getEncryptionKey EncryptionKey}.
* @return string the encrypted data
* @throws CException if PHP Mcrypt extension is not loaded
*/
public function encrypt($data,$key=null)
{
$module=$this->openCryptModule();
$key=substr($key===null ? md5($this->getEncryptionKey()) : $key,0,mcrypt_enc_get_key_size($module));
srand();
$iv=mcrypt_create_iv(mcrypt_enc_get_iv_size($module), MCRYPT_RAND);
mcrypt_generic_init($module,$key,$iv);
$encrypted=$iv.mcrypt_generic($module,$data);
mcrypt_generic_deinit($module);
mcrypt_module_close($module);
return $encrypted;
}
/**
* Decrypts data
* @param string $data data to be decrypted.
* @param string $key the decryption key. This defaults to null, meaning using {@link getEncryptionKey EncryptionKey}.
* @return string the decrypted data
* @throws CException if PHP Mcrypt extension is not loaded
*/
public function decrypt($data,$key=null)
{
$module=$this->openCryptModule();
$key=substr($key===null ? md5($this->getEncryptionKey()) : $key,0,mcrypt_enc_get_key_size($module));
$ivSize=mcrypt_enc_get_iv_size($module);
$iv=substr($data,0,$ivSize);
mcrypt_generic_init($module,$key,$iv);
$decrypted=mdecrypt_generic($module,substr($data,$ivSize));
mcrypt_generic_deinit($module);
mcrypt_module_close($module);
return rtrim($decrypted,"\0");
}
/**
* Opens the mcrypt module with the configuration specified in {@link cryptAlgorithm}.
* @return resource the mycrypt module handle.
* @since 1.1.3
*/
protected function openCryptModule()
{
if(extension_loaded('mcrypt'))
{
if(is_array($this->cryptAlgorithm))
$module=call_user_func_array('mcrypt_module_open',$this->cryptAlgorithm);
else
$module=mcrypt_module_open($this->cryptAlgorithm, '', MCRYPT_MODE_CBC, '');
if($module===false)
throw new CException(Yii::t('yii','Failed to initialize the mcrypt module.'));
return $module;
}
else
throw new CException(Yii::t('yii','CSecurityManager requires PHP mcrypt extension to be loaded in order to use data encryption feature.'));
}
/**
* Prefixes data with an HMAC.
* @param string $data data to be hashed.
* @param string $key the private key to be used for generating HMAC. Defaults to null, meaning using {@link validationKey}.
* @return string data prefixed with HMAC
*/
public function hashData($data,$key=null)
{
return $this->computeHMAC($data,$key).$data;
}
/**
* Validates if data is tampered.
* @param string $data data to be validated. The data must be previously
* generated using {@link hashData()}.
* @param string $key the private key to be used for generating HMAC. Defaults to null, meaning using {@link validationKey}.
* @return string the real data with HMAC stripped off. False if the data
* is tampered.
*/
public function validateData($data,$key=null)
{
$len=strlen($this->computeHMAC('test'));
if(strlen($data)>=$len)
{
$hmac=substr($data,0,$len);
$data2=substr($data,$len);
return $hmac===$this->computeHMAC($data2,$key)?$data2:false;
}
else
return false;
}
/**
* Computes the HMAC for the data with {@link getValidationKey ValidationKey}.
* @param string $data data to be generated HMAC
* @param string $key the private key to be used for generating HMAC. Defaults to null, meaning using {@link validationKey}.
* @return string the HMAC for the data
*/
protected function computeHMAC($data,$key=null)
{
if($key===null)
$key=$this->getValidationKey();
if(function_exists('hash_hmac'))
return hash_hmac($this->hashAlgorithm, $data, $key);
if(!strcasecmp($this->hashAlgorithm,'sha1'))
{
$pack='H40';
$func='sha1';
}
else
{
$pack='H32';
$func='md5';
}
if(strlen($key) > 64)
$key=pack($pack, $func($key));
if(strlen($key) < 64)
$key=str_pad($key, 64, chr(0));
$key=substr($key,0,64);
return $func((str_repeat(chr(0x5C), 64) ^ $key) . pack($pack, $func((str_repeat(chr(0x36), 64) ^ $key) . $data)));
}
}