<?php
/**
* This file contains classes implementing security manager feature.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @link http://www.yiiframework.com/
* @copyright 2008-2013 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()}.
*
* @property string $validationKey The private key used to generate HMAC.
* If the key is not explicitly set, a random one is generated and returned.
* @property string $encryptionKey The private key used to encrypt/decrypt data.
* If the key is not explicitly set, a random one is generated and returned.
* @property string $validation
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @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;
private $_mbstring;
public function init()
{
parent::init();
$this->_mbstring=extension_loaded('mbstring');
}
/**
* @return string a randomly generated private key.
* @deprecated in favor of {@link generateRandomString()} since 1.1.14. Never use this method.
*/
protected function generateRandomKey()
{
return $this->generateRandomString(32);
}
/**
* @return string the private key used to generate HMAC.
* If the key is not explicitly set, a random one is generated and returned.
* @throws CException in case random string cannot be generated.
*/
public function getValidationKey()
{
if($this->_validationKey!==null)
return $this->_validationKey;
else
{
if(($key=Yii::app()->getGlobalState(self::STATE_VALIDATION_KEY))!==null)
$this->setValidationKey($key);
else
{
if(($key=$this->generateRandomString(32,true))===false)
if(($key=$this->generateRandomString(32,false))===false)
throw new CException(Yii::t('yii',
'CSecurityManager::generateRandomString() cannot generate random string in the current environment.'));
$this->setValidationKey($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.
* @throws CException in case random string cannot be generated.
*/
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
{
if(($key=$this->generateRandomString(32,true))===false)
if(($key=$this->generateRandomString(32,false))===false)
throw new CException(Yii::t('yii',
'CSecurityManager::generateRandomString() cannot generate random string in the current environment.'));
$this->setEncryptionKey($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 -
* @deprecated
*/
public function getValidation()
{
return $this->hashAlgorithm;
}
/**
* This method has been deprecated since version 1.1.3.
* Please use {@link hashAlgorithm} instead.
* @param string $value -
* @deprecated
*/
public function setValidation($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();
$key=$this->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();
$key=$this->substr($key===null ? md5($this->getEncryptionKey()) : $key,0,mcrypt_enc_get_key_size($module));
$ivSize=mcrypt_enc_get_iv_size($module);
$iv=$this->substr($data,0,$ivSize);
mcrypt_generic_init($module,$key,$iv);
$decrypted=mdecrypt_generic($module,$this->substr($data,$ivSize,$this->strlen($data)));
mcrypt_generic_deinit($module);
mcrypt_module_close($module);
return rtrim($decrypted,"\0");
}
/**
* Opens the mcrypt module with the configuration specified in {@link cryptAlgorithm}.
* @throws CException if failed to initialize the mcrypt module or PHP mcrypt extension
* @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)
{
$len=$this->strlen($this->computeHMAC('test'));
if($this->strlen($data)>=$len)
{
$hmac=$this->substr($data,0,$len);
$data2=$this->substr($data,$len,$this->strlen($data));
return $hmac===$this->computeHMAC($data2,$key)?$data2:false;
}
else
return false;
}
/**
* Computes the HMAC for the data with {@link getValidationKey validationKey}. This method has been made public
* since 1.1.14.
* @param string $data data to be generated HMAC.
* @param string|null $key the private key to be used for generating HMAC. Defaults to null, meaning using
* {@link validationKey} value.
* @param string|null $hashAlgorithm the name of the hashing algorithm to be used.
* See {@link http://php.net/manual/en/function.hash-algos.php hash-algos} for the list of possible
* hash algorithms. Note that if you are using PHP 5.1.1 or below, you can only use 'sha1' or 'md5'.
* Defaults to null, meaning using {@link hashAlgorithm} value.
* @return string the HMAC for the data.
* @throws CException on unsupported hash algorithm given.
*/
public function computeHMAC($data,$key=null,$hashAlgorithm=null)
{
if($key===null)
$key=$this->getValidationKey();
if($hashAlgorithm===null)
$hashAlgorithm=$this->hashAlgorithm;
if(function_exists('hash_hmac'))
return hash_hmac($hashAlgorithm,$data,$key);
if(0===strcasecmp($hashAlgorithm,'sha1'))
{
$pack='H40';
$func='sha1';
}
elseif(0===strcasecmp($hashAlgorithm,'md5'))
{
$pack='H32';
$func='md5';
}
else
{
throw new CException(Yii::t('yii','Only SHA1 and MD5 hashing algorithms are supported when using PHP 5.1.1 or below.'));
}
if($this->strlen($key)>64)
$key=pack($pack,$func($key));
if($this->strlen($key)<64)
$key=str_pad($key,64,chr(0));
$key=$this->substr($key,0,64);
return $func((str_repeat(chr(0x5C), 64) ^ $key) . pack($pack, $func((str_repeat(chr(0x36), 64) ^ $key) . $data)));
}
/**
* Generate a random ASCII string. Generates only [0-9a-zA-z_~] characters which are all
* transparent in raw URL encoding.
* @param integer $length length of the generated string in characters.
* @param boolean $cryptographicallyStrong set this to require cryptographically strong randomness.
* @return string|boolean random string or false in case it cannot be generated.
* @since 1.1.14
*/
public function generateRandomString($length,$cryptographicallyStrong=true)
{
if(($randomBytes=$this->generateRandomBytes($length+2,$cryptographicallyStrong))!==false)
return strtr($this->substr(base64_encode($randomBytes),0,$length),array('+'=>'_','/'=>'~'));
return false;
}
/**
* Generates a string of random bytes.
* @param integer $length number of random bytes to be generated.
* @param boolean $cryptographicallyStrong whether to fail if a cryptographically strong
* result cannot be generated. The method attempts to read from a cryptographically strong
* pseudorandom number generator (CS-PRNG), see
* {@link https://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator#Requirements Wikipedia}.
* However, in some runtime environments, PHP has no access to a CS-PRNG, in which case
* the method returns false if $cryptographicallyStrong is true. When $cryptographicallyStrong is false,
* the method always returns a pseudorandom result but may fall back to using {@link generatePseudoRandomBlock}.
* This method does not guarantee that entropy, from sources external to the CS-PRNG, was mixed into
* the CS-PRNG state between each successive call. The caller can therefore expect non-blocking
* behavior, unlike, for example, reading from /dev/random on Linux, see
* {@link http://eprint.iacr.org/2006/086.pdf Gutterman et al 2006}.
* @return boolean|string generated random binary string or false on failure.
* @since 1.1.14
*/
public function generateRandomBytes($length,$cryptographicallyStrong=true)
{
$bytes='';
if(function_exists('openssl_random_pseudo_bytes'))
{
$bytes=openssl_random_pseudo_bytes($length,$strong);
if($this->strlen($bytes)>=$length && ($strong || !$cryptographicallyStrong))
return $this->substr($bytes,0,$length);
}
if(function_exists('mcrypt_create_iv') &&
($bytes=mcrypt_create_iv($length, MCRYPT_DEV_URANDOM))!==false &&
$this->strlen($bytes)>=$length)
{
return $this->substr($bytes,0,$length);
}
if(($file=@fopen('/dev/urandom','rb'))!==false &&
($bytes=@fread($file,$length))!==false &&
(fclose($file) || true) &&
$this->strlen($bytes)>=$length)
{
return $this->substr($bytes,0,$length);
}
$i=0;
while($this->strlen($bytes)<$length &&
($byte=$this->generateSessionRandomBlock())!==false &&
++$i<3)
{
$bytes.=$byte;
}
if($this->strlen($bytes)>=$length)
return $this->substr($bytes,0,$length);
if ($cryptographicallyStrong)
return false;
while($this->strlen($bytes)<$length)
$bytes.=$this->generatePseudoRandomBlock();
return $this->substr($bytes,0,$length);
}
/**
* Generate a pseudo random block of data using several sources. On some systems this may be a bit
* better than PHP's {@link mt_rand} built-in function, which is not really random.
* @return string of 64 pseudo random bytes.
* @since 1.1.14
*/
public function generatePseudoRandomBlock()
{
$bytes='';
if (function_exists('openssl_random_pseudo_bytes')
&& ($bytes=openssl_random_pseudo_bytes(512))!==false
&& $this->strlen($bytes)>=512)
{
return $this->substr($bytes,0,512);
}
for($i=0;$i<32;++$i)
$bytes.=pack('S',mt_rand(0,0xffff));
// On UNIX and UNIX-like operating systems the numerical values in `ps`, `uptime` and `iostat`
// ought to be fairly unpredictable. Gather the non-zero digits from those.
foreach(array('ps','uptime','iostat') as $command) {
@exec($command,$commandResult,$retVal);
if(is_array($commandResult) && !empty($commandResult) && $retVal==0)
$bytes.=preg_replace('/[^1-9]/','',implode('',$commandResult));
}
// Gather the current time's microsecond part. Note: this is only a source of entropy on
// the first call! If multiple calls are made, the entropy is only as much as the
// randomness in the time between calls.
$bytes.=$this->substr(microtime(),2,6);
// Concatenate everything gathered, mix it with sha512. hash() is part of PHP core and
// enabled by default but it can be disabled at compile time but we ignore that possibility here.
return hash('sha512',$bytes,true);
}
/**
* Get random bytes from the system entropy source via PHP session manager.
* @return boolean|string 20-byte random binary string or false on error.
* @since 1.1.14
*/
public function generateSessionRandomBlock()
{
ini_set('session.entropy_length',20);
if(ini_get('session.entropy_length')!=20)
return false;
// These calls are (supposed to be, according to PHP manual) safe even if
// there is already an active session for the calling script.
@session_start();
@session_regenerate_id();
$bytes=session_id();
if(!$bytes)
return false;
// $bytes has 20 bytes of entropy but the session manager converts the binary
// random bytes into something readable. We have to convert that back.
// SHA-1 should do it without losing entropy.
return sha1($bytes,true);
}
/**
* Returns the length of the given string.
* If available uses the multibyte string function mb_strlen.
* @param string $string the string being measured for length
* @return integer the length of the string
*/
private function strlen($string)
{
return $this->_mbstring ? mb_strlen($string,'8bit') : strlen($string);
}
/**
* Returns the portion of string specified by the start and length parameters.
* If available uses the multibyte string function mb_substr
* @param string $string the input string. Must be one character or longer.
* @param integer $start the starting position
* @param integer $length the desired portion length
* @return string the extracted part of string, or FALSE on failure or an empty string.
*/
private function substr($string,$start,$length)
{
return $this->_mbstring ? mb_substr($string,$start,$length,'8bit') : substr($string,$start,$length);
}
}