cakephp2-php8/lib/Cake/Utility/Security.php
mark_story 974ac44fb4 Use random iv values in rijndael.
Using fixed iv values has a number of known problems like dictionary
attacks against the cipher key. Use a random iv value for all future
encrpyted values. Provide backwards compatibility for values encrypted
with fixed iv's, and silently upgrade values for enhanced security.
2013-02-09 20:48:27 -05:00

284 lines
7.9 KiB
PHP

<?php
/**
* Core Security
*
* PHP 5
*
* CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
* Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
*
* Licensed under The MIT License
* For full copyright and license information, please see the LICENSE.txt
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
* @link http://cakephp.org CakePHP(tm) Project
* @package Cake.Utility
* @since CakePHP(tm) v .0.10.0.1233
* @license MIT License (http://www.opensource.org/licenses/mit-license.php)
*/
App::uses('String', 'Utility');
/**
* Security Library contains utility methods related to security
*
* @package Cake.Utility
*/
class Security {
/**
* Default hash method
*
* @var string
*/
public static $hashType = null;
/**
* Default cost
*
* @var string
*/
public static $hashCost = '10';
/**
* Get allowed minutes of inactivity based on security level.
*
* @deprecated Exists for backwards compatibility only, not used by the core
* @return integer Allowed inactivity in minutes
*/
public static function inactiveMins() {
switch (Configure::read('Security.level')) {
case 'high':
return 10;
case 'medium':
return 100;
case 'low':
default:
return 300;
}
}
/**
* Generate authorization hash.
*
* @return string Hash
*/
public static function generateAuthKey() {
return Security::hash(String::uuid());
}
/**
* Validate authorization hash.
*
* @param string $authKey Authorization hash
* @return boolean Success
*/
public static function validateAuthKey($authKey) {
return true;
}
/**
* Create a hash from string using given method or fallback on next available method.
*
* #### Using Blowfish
*
* - Creating Hashes: *Do not supply a salt*. Cake handles salt creation for
* you ensuring that each hashed password will have a *unique* salt.
* - Comparing Hashes: Simply pass the originally hashed password as the salt.
* The salt is prepended to the hash and php handles the parsing automagically.
* For convenience the BlowfishAuthenticate adapter is available for use with
* the AuthComponent.
* - Do NOT use a constant salt for blowfish!
*
* Creating a blowfish/bcrypt hash:
*
* {{{
* $hash = Security::hash($password, 'blowfish');
* }}}
*
* @param string $string String to hash
* @param string $type Method to use (sha1/sha256/md5/blowfish)
* @param mixed $salt If true, automatically appends the application's salt
* value to $string (Security.salt). If you are using blowfish the salt
* must be false or a previously generated salt.
* @return string Hash
*/
public static function hash($string, $type = null, $salt = false) {
if (empty($type)) {
$type = self::$hashType;
}
$type = strtolower($type);
if ($type === 'blowfish') {
return self::_crypt($string, $salt);
}
if ($salt) {
if (!is_string($salt)) {
$salt = Configure::read('Security.salt');
}
$string = $salt . $string;
}
if (!$type || $type == 'sha1') {
if (function_exists('sha1')) {
return sha1($string);
}
$type = 'sha256';
}
if ($type == 'sha256' && function_exists('mhash')) {
return bin2hex(mhash(MHASH_SHA256, $string));
}
if (function_exists('hash')) {
return hash($type, $string);
}
return md5($string);
}
/**
* Sets the default hash method for the Security object. This affects all objects using
* Security::hash().
*
* @param string $hash Method to use (sha1/sha256/md5/blowfish)
* @return void
* @see Security::hash()
*/
public static function setHash($hash) {
self::$hashType = $hash;
}
/**
* Sets the cost for they blowfish hash method.
*
* @param integer $cost Valid values are 4-31
* @return void
*/
public static function setCost($cost) {
if ($cost < 4 || $cost > 31) {
trigger_error(__d(
'cake_dev',
'Invalid value, cost must be between %s and %s',
array(4, 31)
), E_USER_WARNING);
return null;
}
self::$hashCost = $cost;
}
/**
* Encrypts/Decrypts a text using the given key.
*
* @param string $text Encrypted string to decrypt, normal string to encrypt
* @param string $key Key to use
* @return string Encrypted/Decrypted string
*/
public static function cipher($text, $key) {
if (empty($key)) {
trigger_error(__d('cake_dev', 'You cannot use an empty key for Security::cipher()'), E_USER_WARNING);
return '';
}
srand(Configure::read('Security.cipherSeed'));
$out = '';
$keyLength = strlen($key);
for ($i = 0, $textLength = strlen($text); $i < $textLength; $i++) {
$j = ord(substr($key, $i % $keyLength, 1));
while ($j--) {
rand(0, 255);
}
$mask = rand(0, 255);
$out .= chr(ord(substr($text, $i, 1)) ^ $mask);
}
srand();
return $out;
}
/**
* Encrypts/Decrypts a text using the given key using rijndael method.
*
* Prior to 2.3.1, a fixed initialization vector was used. This was not
* secure. This method now uses a random iv, and will silently upgrade values when
* they are re-encrypted.
*
* @param string $text Encrypted string to decrypt, normal string to encrypt
* @param string $key Key to use as the encryption key for encrypted data.
* @param string $operation Operation to perform, encrypt or decrypt
* @return string Encrypted/Descrypted string
*/
public static function rijndael($text, $key, $operation) {
if (empty($key)) {
trigger_error(__d('cake_dev', 'You cannot use an empty key for Security::rijndael()'), E_USER_WARNING);
return '';
}
if (empty($operation) || !in_array($operation, array('encrypt', 'decrypt'))) {
trigger_error(__d('cake_dev', 'You must specify the operation for Security::rijndael(), either encrypt or decrypt'), E_USER_WARNING);
return '';
}
if (strlen($key) < 32) {
trigger_error(__d('cake_dev', 'You must use a key larger than 32 bytes for Security::rijndael()'), E_USER_WARNING);
return '';
}
$algorithm = MCRYPT_RIJNDAEL_256;
$mode = MCRYPT_MODE_CBC;
$ivSize = mcrypt_get_iv_size($algorithm, $mode);
$cryptKey = substr($key, 0, 32);
if ($operation === 'encrypt') {
$iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
return $iv . '$$' . mcrypt_encrypt($algorithm, $cryptKey, $text, $mode, $iv);
}
// Backwards compatible decrypt with fixed iv
if (substr($text, $ivSize, 2) !== '$$') {
$iv = substr($key, strlen($key) - 32, 32);
return rtrim(mcrypt_decrypt($algorithm, $cryptKey, $text, $mode, $iv), "\0");
}
$iv = substr($text, 0, $ivSize);
$text = substr($text, $ivSize + 2);
return rtrim(mcrypt_decrypt($algorithm, $cryptKey, $text, $mode, $iv), "\0");
}
/**
* Generates a pseudo random salt suitable for use with php's crypt() function.
* The salt length should not exceed 27. The salt will be composed of
* [./0-9A-Za-z]{$length}.
*
* @param integer $length The length of the returned salt
* @return string The generated salt
*/
protected static function _salt($length = 22) {
$salt = str_replace(
array('+', '='),
'.',
base64_encode(sha1(uniqid(Configure::read('Security.salt'), true), true))
);
return substr($salt, 0, $length);
}
/**
* One way encryption using php's crypt() function. To use blowfish hashing see ``Security::hash()``
*
* @param string $password The string to be encrypted.
* @param mixed $salt false to generate a new salt or an existing salt.
* @return string The hashed string or an empty string on error.
*/
protected static function _crypt($password, $salt = false) {
if ($salt === false) {
$salt = self::_salt(22);
$salt = vsprintf('$2a$%02d$%s', array(self::$hashCost, $salt));
}
if ($salt === true || strpos($salt, '$2a$') !== 0 || strlen($salt) < 29) {
trigger_error(__d(
'cake_dev',
'Invalid salt: %s for %s Please visit http://www.php.net/crypt and read the appropriate section for building %s salts.',
array($salt, 'blowfish', 'blowfish')
), E_USER_WARNING);
return '';
}
return crypt($password, $salt);
}
}