380 lines
11 KiB
PHP
380 lines
11 KiB
PHP
<?php
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/**
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* Core Security
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*
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* CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
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* Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
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*
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* Licensed under The MIT License
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* For full copyright and license information, please see the LICENSE.txt
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* Redistributions of files must retain the above copyright notice.
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*
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* @copyright Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
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* @link http://cakephp.org CakePHP(tm) Project
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* @package Cake.Utility
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* @since CakePHP(tm) v .0.10.0.1233
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* @license http://www.opensource.org/licenses/mit-license.php MIT License
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*/
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App::uses('String', 'Utility');
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/**
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* Security Library contains utility methods related to security
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*
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* @package Cake.Utility
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*/
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class Security {
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/**
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* Default hash method
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*
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* @var string
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*/
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public static $hashType = null;
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/**
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* Default cost
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*
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* @var string
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*/
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public static $hashCost = '10';
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/**
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* Get allowed minutes of inactivity based on security level.
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*
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* @deprecated Exists for backwards compatibility only, not used by the core
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* @return integer Allowed inactivity in minutes
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*/
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public static function inactiveMins() {
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switch (Configure::read('Security.level')) {
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case 'high':
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return 10;
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case 'medium':
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return 100;
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case 'low':
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default:
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return 300;
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}
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}
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/**
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* Generate authorization hash.
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*
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* @return string Hash
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*/
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public static function generateAuthKey() {
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return Security::hash(String::uuid());
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}
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/**
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* Validate authorization hash.
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*
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* @param string $authKey Authorization hash
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* @return boolean Success
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*/
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public static function validateAuthKey($authKey) {
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return true;
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}
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/**
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* Create a hash from string using given method or fallback on next available method.
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*
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* #### Using Blowfish
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*
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* - Creating Hashes: *Do not supply a salt*. Cake handles salt creation for
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* you ensuring that each hashed password will have a *unique* salt.
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* - Comparing Hashes: Simply pass the originally hashed password as the salt.
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* The salt is prepended to the hash and php handles the parsing automagically.
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* For convenience the `BlowfishPasswordHasher` class is available for use with
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* the AuthComponent.
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* - Do NOT use a constant salt for blowfish!
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*
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* Creating a blowfish/bcrypt hash:
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*
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* {{{
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* $hash = Security::hash($password, 'blowfish');
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* }}}
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*
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* @param string $string String to hash
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* @param string $type Method to use (sha1/sha256/md5/blowfish)
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* @param mixed $salt If true, automatically prepends the application's salt
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* value to $string (Security.salt). If you are using blowfish the salt
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* must be false or a previously generated salt.
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* @return string Hash
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* @link http://book.cakephp.org/2.0/en/core-utility-libraries/security.html#Security::hash
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*/
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public static function hash($string, $type = null, $salt = false) {
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if (empty($type)) {
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$type = self::$hashType;
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}
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$type = strtolower($type);
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if ($type === 'blowfish') {
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return self::_crypt($string, $salt);
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}
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if ($salt) {
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if (!is_string($salt)) {
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$salt = Configure::read('Security.salt');
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}
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$string = $salt . $string;
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}
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if (!$type || $type === 'sha1') {
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if (function_exists('sha1')) {
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return sha1($string);
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}
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$type = 'sha256';
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}
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if ($type === 'sha256' && function_exists('mhash')) {
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return bin2hex(mhash(MHASH_SHA256, $string));
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}
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if (function_exists('hash')) {
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return hash($type, $string);
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}
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return md5($string);
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}
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/**
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* Sets the default hash method for the Security object. This affects all objects using
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* Security::hash().
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*
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* @param string $hash Method to use (sha1/sha256/md5/blowfish)
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* @return void
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* @see Security::hash()
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*/
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public static function setHash($hash) {
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self::$hashType = $hash;
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}
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/**
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* Sets the cost for they blowfish hash method.
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*
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* @param integer $cost Valid values are 4-31
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* @return void
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*/
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public static function setCost($cost) {
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if ($cost < 4 || $cost > 31) {
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trigger_error(__d(
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'cake_dev',
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'Invalid value, cost must be between %s and %s',
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array(4, 31)
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), E_USER_WARNING);
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return null;
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}
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self::$hashCost = $cost;
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}
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/**
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* Runs $text through a XOR cipher.
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*
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* *Note* This is not a cryptographically strong method and should not be used
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* for sensitive data. Additionally this method does *not* work in environments
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* where suhosin is enabled.
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*
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* Instead you should use Security::rijndael() when you need strong
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* encryption.
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*
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* @param string $text Encrypted string to decrypt, normal string to encrypt
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* @param string $key Key to use
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* @return string Encrypted/Decrypted string
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* @deprecated Will be removed in 3.0.
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*/
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public static function cipher($text, $key) {
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if (empty($key)) {
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trigger_error(__d('cake_dev', 'You cannot use an empty key for %s', 'Security::cipher()'), E_USER_WARNING);
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return '';
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}
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srand(Configure::read('Security.cipherSeed'));
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$out = '';
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$keyLength = strlen($key);
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for ($i = 0, $textLength = strlen($text); $i < $textLength; $i++) {
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$j = ord(substr($key, $i % $keyLength, 1));
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while ($j--) {
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rand(0, 255);
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}
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$mask = rand(0, 255);
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$out .= chr(ord(substr($text, $i, 1)) ^ $mask);
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}
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srand();
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return $out;
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}
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/**
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* Encrypts/Decrypts a text using the given key using rijndael method.
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*
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* Prior to 2.3.1, a fixed initialization vector was used. This was not
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* secure. This method now uses a random iv, and will silently upgrade values when
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* they are re-encrypted.
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*
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* @param string $text Encrypted string to decrypt, normal string to encrypt
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* @param string $key Key to use as the encryption key for encrypted data.
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* @param string $operation Operation to perform, encrypt or decrypt
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* @return string Encrypted/Decrypted string
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*/
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public static function rijndael($text, $key, $operation) {
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if (empty($key)) {
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trigger_error(__d('cake_dev', 'You cannot use an empty key for %s', 'Security::rijndael()'), E_USER_WARNING);
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return '';
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}
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if (empty($operation) || !in_array($operation, array('encrypt', 'decrypt'))) {
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trigger_error(__d('cake_dev', 'You must specify the operation for Security::rijndael(), either encrypt or decrypt'), E_USER_WARNING);
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return '';
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}
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if (strlen($key) < 32) {
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trigger_error(__d('cake_dev', 'You must use a key larger than 32 bytes for Security::rijndael()'), E_USER_WARNING);
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return '';
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}
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$algorithm = MCRYPT_RIJNDAEL_256;
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$mode = MCRYPT_MODE_CBC;
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$ivSize = mcrypt_get_iv_size($algorithm, $mode);
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$cryptKey = substr($key, 0, 32);
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if ($operation === 'encrypt') {
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$iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
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return $iv . '$$' . mcrypt_encrypt($algorithm, $cryptKey, $text, $mode, $iv);
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}
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// Backwards compatible decrypt with fixed iv
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if (substr($text, $ivSize, 2) !== '$$') {
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$iv = substr($key, strlen($key) - 32, 32);
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return rtrim(mcrypt_decrypt($algorithm, $cryptKey, $text, $mode, $iv), "\0");
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}
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$iv = substr($text, 0, $ivSize);
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$text = substr($text, $ivSize + 2);
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return rtrim(mcrypt_decrypt($algorithm, $cryptKey, $text, $mode, $iv), "\0");
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}
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/**
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* Generates a pseudo random salt suitable for use with php's crypt() function.
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* The salt length should not exceed 27. The salt will be composed of
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* [./0-9A-Za-z]{$length}.
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*
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* @param integer $length The length of the returned salt
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* @return string The generated salt
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*/
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protected static function _salt($length = 22) {
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$salt = str_replace(
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array('+', '='),
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'.',
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base64_encode(sha1(uniqid(Configure::read('Security.salt'), true), true))
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);
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return substr($salt, 0, $length);
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}
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/**
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* One way encryption using php's crypt() function. To use blowfish hashing see ``Security::hash()``
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*
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* @param string $password The string to be encrypted.
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* @param mixed $salt false to generate a new salt or an existing salt.
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* @return string The hashed string or an empty string on error.
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*/
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protected static function _crypt($password, $salt = false) {
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if ($salt === false) {
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$salt = self::_salt(22);
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$salt = vsprintf('$2a$%02d$%s', array(self::$hashCost, $salt));
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}
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if ($salt === true || strpos($salt, '$2a$') !== 0 || strlen($salt) < 29) {
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trigger_error(__d(
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'cake_dev',
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'Invalid salt: %s for %s Please visit http://www.php.net/crypt and read the appropriate section for building %s salts.',
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array($salt, 'blowfish', 'blowfish')
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), E_USER_WARNING);
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return '';
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}
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return crypt($password, $salt);
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}
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/**
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* Encrypt a value using AES-256.
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*
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* *Caveat* You cannot properly encrypt/decrypt data with trailing null bytes.
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* Any trailing null bytes will be removed on decryption due to how PHP pads messages
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* with nulls prior to encryption.
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*
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* @param string $plain The value to encrypt.
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* @param string $key The 256 bit/32 byte key to use as a cipher key.
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* @param string $hmacSalt The salt to use for the HMAC process. Leave null to use Security.salt.
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* @return string Encrypted data.
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* @throws CakeException On invalid data or key.
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*/
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public static function encrypt($plain, $key, $hmacSalt = null) {
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self::_checkKey($key, 'encrypt()');
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if ($hmacSalt === null) {
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$hmacSalt = Configure::read('Security.salt');
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}
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// Generate the encryption and hmac key.
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$key = substr(hash('sha256', $key . $hmacSalt), 0, 32);
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$algorithm = MCRYPT_RIJNDAEL_128;
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$mode = MCRYPT_MODE_CBC;
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$ivSize = mcrypt_get_iv_size($algorithm, $mode);
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$iv = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM);
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$ciphertext = $iv . mcrypt_encrypt($algorithm, $key, $plain, $mode, $iv);
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$hmac = hash_hmac('sha256', $ciphertext, $key);
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return $hmac . $ciphertext;
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}
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/**
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* Check the encryption key for proper length.
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*
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* @param string $key
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* @param string $method The method the key is being checked for.
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* @return void
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* @throws CakeException When key length is not 256 bit/32 bytes
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*/
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protected static function _checkKey($key, $method) {
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if (strlen($key) < 32) {
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throw new CakeException(__d('cake_dev', 'Invalid key for %s, key must be at least 256 bits (32 bytes) long.', $method));
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}
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}
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/**
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* Decrypt a value using AES-256.
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*
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* @param string $cipher The ciphertext to decrypt.
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* @param string $key The 256 bit/32 byte key to use as a cipher key.
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* @param string $hmacSalt The salt to use for the HMAC process. Leave null to use Security.salt.
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* @return string Decrypted data. Any trailing null bytes will be removed.
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* @throws CakeException On invalid data or key.
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*/
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public static function decrypt($cipher, $key, $hmacSalt = null) {
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self::_checkKey($key, 'decrypt()');
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if (empty($cipher)) {
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throw new CakeException(__d('cake_dev', 'The data to decrypt cannot be empty.'));
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}
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if ($hmacSalt === null) {
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$hmacSalt = Configure::read('Security.salt');
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}
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// Generate the encryption and hmac key.
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$key = substr(hash('sha256', $key . $hmacSalt), 0, 32);
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// Split out hmac for comparison
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$macSize = 64;
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$hmac = substr($cipher, 0, $macSize);
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$cipher = substr($cipher, $macSize);
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$compareHmac = hash_hmac('sha256', $cipher, $key);
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if ($hmac !== $compareHmac) {
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return false;
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}
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$algorithm = MCRYPT_RIJNDAEL_128;
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$mode = MCRYPT_MODE_CBC;
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$ivSize = mcrypt_get_iv_size($algorithm, $mode);
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$iv = substr($cipher, 0, $ivSize);
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$cipher = substr($cipher, $ivSize);
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$plain = mcrypt_decrypt($algorithm, $key, $cipher, $mode, $iv);
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return rtrim($plain, "\0");
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}
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}
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