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Diffstat (limited to 'system/libraries/Encryption.php')
| -rw-r--r-- | system/libraries/Encryption.php | 887 |
1 files changed, 887 insertions, 0 deletions
diff --git a/system/libraries/Encryption.php b/system/libraries/Encryption.php new file mode 100644 index 000000000..3a5409839 --- /dev/null +++ b/system/libraries/Encryption.php @@ -0,0 +1,887 @@ +<?php +/** + * CodeIgniter + * + * An open source application development framework for PHP 5.2.4 or newer + * + * NOTICE OF LICENSE + * + * Licensed under the Open Software License version 3.0 + * + * This source file is subject to the Open Software License (OSL 3.0) that is + * bundled with this package in the files license.txt / license.rst. It is + * also available through the world wide web at this URL: + * http://opensource.org/licenses/OSL-3.0 + * If you did not receive a copy of the license and are unable to obtain it + * through the world wide web, please send an email to + * licensing@ellislab.com so we can send you a copy immediately. + * + * @package CodeIgniter + * @author EllisLab Dev Team + * @copyright Copyright (c) 2008 - 2013, EllisLab, Inc. (http://ellislab.com/) + * @license http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0) + * @link http://codeigniter.com + * @since Version 3.0 + * @filesource + */ +defined('BASEPATH') OR exit('No direct script access allowed'); + +/** + * CodeIgniter Encryption Class + * + * Provides two-way keyed encryption via PHP's MCrypt and/or OpenSSL extensions. + * + * @package CodeIgniter + * @subpackage Libraries + * @category Libraries + * @author Andrey Andreev + * @link http://codeigniter.com/user_guide/libraries/encryption.html + */ +class CI_Encryption { + + /** + * Encryption cipher + * + * @var string + */ + protected $_cipher = 'aes-128'; + + /** + * Cipher mode + * + * @var string + */ + protected $_mode = 'cbc'; + + /** + * Cipher handle + * + * @var mixed + */ + protected $_handle; + + /** + * Encryption key + * + * @var string + */ + protected $_key; + + /** + * PHP extension to be used + * + * @var string + */ + protected $_driver; + + /** + * List of usable drivers (PHP extensions) + * + * @var array + */ + protected $_drivers = array(); + + /** + * List of available modes + * + * @var array + */ + protected $_modes = array( + 'mcrypt' => array( + 'cbc' => 'cbc', + 'ecb' => 'ecb', + 'ofb' => 'nofb', + 'ofb8' => 'ofb', + 'cfb' => 'ncfb', + 'cfb8' => 'cfb', + 'ctr' => 'ctr', + 'stream' => 'stream' + ), + 'openssl' => array( + 'cbc' => 'cbc', + 'ecb' => 'ecb', + 'ofb' => 'ofb', + 'cfb' => 'cfb', + 'cfb8' => 'cfb8', + 'ctr' => 'ctr', + 'stream' => '', + 'gcm' => 'gcm', + 'xts' => 'xts' + ) + ); + + /** + * List of supported HMAC algorightms + * + * name => digest size pairs + * + * @var array + */ + protected $_digests = array( + 'sha224' => 28, + 'sha256' => 32, + 'sha384' => 48, + 'sha512' => 64 + ); + + // -------------------------------------------------------------------- + + /** + * Class constructor + * + * @param array $params Configuration parameters + * @return void + */ + public function __construct(array $params = array()) + { + $this->_drivers = array( + 'mcrypt' => defined('MCRYPT_DEV_URANDOM'), + // While OpenSSL is available for PHP 5.3.0, an IV parameter + // for the encrypt/decrypt functions is only available since 5.3.3 + 'openssl' => (is_php('5.3.3') && extension_loaded('openssl')) + ); + + if ( ! $this->_drivers['mcrypt'] && ! $this->_drivers['openssl']) + { + return show_error('Encryption: Unable to find an available encryption driver.'); + } + + $this->initialize($params); + if ( ! isset($this->_key) && strlen($key = config_item('encryption_key')) > 0) + { + $this->_key = $key; + } + + log_message('debug', 'Encryption Class Initialized'); + } + + // -------------------------------------------------------------------- + + /** + * Initialize + * + * @param array $params Configuration parameters + * @return CI_Encryption + */ + public function initialize(array $params) + { + if ( ! empty($params['driver'])) + { + if (isset($this->_drivers[$params['driver']])) + { + if ($this->_drivers[$params['driver']]) + { + $this->_driver = $params['driver']; + } + else + { + log_message('error', "Encryption: Driver '".$params['driver']."' is not available."); + } + } + else + { + log_message('error', "Encryption: Unknown driver '".$params['driver']."' cannot be configured."); + } + } + + if (empty($this->_driver)) + { + $this->_driver = ($this->_drivers['openssl'] === TRUE) + ? 'openssl' + : 'mcrypt'; + + log_message('debug', "Encryption: Auto-configured driver '".$this->_driver."'."); + } + + empty($params['key']) OR $this->_key = $params['key']; + $this->{'_'.$this->_driver.'_initialize'}($params); + return $this; + } + + // -------------------------------------------------------------------- + + /** + * Initialize MCrypt + * + * @param array $params Configuration parameters + * @return void + */ + protected function _mcrypt_initialize($params) + { + if ( ! empty($params['cipher'])) + { + $params['cipher'] = strtolower($params['cipher']); + $this->_cipher_alias($params['cipher']); + + if ( ! in_array($params['cipher'], mcrypt_list_algorithms(), TRUE)) + { + log_message('error', 'Encryption: MCrypt cipher '.strtoupper($params['cipher']).' is not available.'); + } + else + { + $this->_cipher = $params['cipher']; + } + } + + if ( ! empty($params['mode'])) + { + $params['mode'] = strtolower($params['mode']); + if ( ! isset($this->_modes['mcrypt'][$params['mode']])) + { + log_message('error', 'Encryption: MCrypt mode '.strtotupper($params['mode']).' is not available.'); + } + else + { + $this->_mode = $this->_modes['mcrypt'][$params['mode']]; + } + } + + if (isset($this->_cipher, $this->_mode)) + { + if (is_resource($this->_handle) + && (strtolower(mcrypt_enc_get_algorithms_name($this->_handle)) !== $this->_cipher + OR strtolower(mcrypt_enc_get_modes_name($this->_handle)) !== $this->_mode) + ) + { + mcrypt_module_close($this->_handle); + } + + if ($this->_handle = mcrypt_module_open($this->_cipher, '', $this->_mode, '')) + { + log_message('debug', 'Encryption: MCrypt cipher '.strtoupper($this->_cipher).' initialized in '.strtoupper($this->_mode).' mode.'); + } + else + { + log_message('error', 'Encryption: Unable to initialize MCrypt with cipher '.strtoupper($this->_cipher).' in '.strtoupper($this->_mode).' mode.'); + } + } + } + + // -------------------------------------------------------------------- + + /** + * Initialize OpenSSL + * + * @param array $params Configuration parameters + * @return void + */ + protected function _openssl_initialize($params) + { + if ( ! empty($params['cipher'])) + { + $params['cipher'] = strtolower($params['cipher']); + $this->_cipher_alias($params['cipher']); + $this->_cipher = $params['cipher']; + } + + if ( ! empty($params['mode'])) + { + $params['mode'] = strtolower($params['mode']); + if ( ! isset($this->_modes['openssl'][$params['mode']])) + { + log_message('error', 'Encryption: OpenSSL mode '.strtotupper($params['mode']).' is not available.'); + } + else + { + $this->_mode = $this->_modes['openssl'][$params['mode']]; + } + } + + if (isset($this->_cipher, $this->_mode)) + { + // This is mostly for the stream mode, which doesn't get suffixed in OpenSSL + $handle = empty($this->_mode) + ? $this->_cipher + : $this->_cipher.'-'.$this->_mode; + + if ( ! in_array($handle, openssl_get_cipher_methods(), TRUE)) + { + $this->_handle = NULL; + log_message('error', 'Encryption: Unable to initialize OpenSSL with method '.strtoupper($handle).'.'); + } + else + { + $this->_handle = $handle; + log_message('debug', 'Encryption: OpenSSL initialized with method '.strtoupper($handle).'.'); + } + } + } + + // -------------------------------------------------------------------- + + /** + * Encrypt + * + * @param string $data Input data + * @param array $params Input parameters + * @return string + */ + public function encrypt($data, array $params = NULL) + { + if (($params = $this->_get_params($params)) === FALSE) + { + return FALSE; + } + + isset($params['key']) OR $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption'); + + if (($data = $this->{'_'.$this->_driver.'_encrypt'}($data, $params)) === FALSE) + { + return FALSE; + } + + $params['base64'] && $data = base64_encode($data); + + if (isset($params['hmac_digest'])) + { + isset($params['hmac_key']) OR $params['hmac_key'] = $this->hkdf($this->_key, 'sha512', NULL, NULL, 'authentication'); + return hash_hmac($params['hmac_digest'], $data, $params['hmac_key'], ! $params['base64']).$data; + } + + return $data; + } + + // -------------------------------------------------------------------- + + /** + * Encrypt via MCrypt + * + * @param string $data Input data + * @param array $params Input parameters + * @return string + */ + protected function _mcrypt_encrypt($data, $params) + { + if ( ! is_resource($params['handle'])) + { + return FALSE; + } + elseif ( ! isset($params['iv'])) + { + // The greater-than-1 comparison is mostly a work-around for a bug, + // where 1 is returned for ARCFour instead of 0. + $params['iv'] = (($iv_size = mcrypt_enc_get_iv_size($params['handle'])) > 1) + ? mcrypt_create_iv($iv_size, MCRYPT_DEV_URANDOM) + : NULL; + } + + // CAST-128 compatibility (http://tools.ietf.org/rfc/rfc2144.txt) + // + // RFC2144 says that keys shorter than 16 bytes are to be padded with + // zero bytes to 16 bytes, but (surprise) MCrypt doesn't do that. + if ($params['cipher'] === 'cast-128' && ($kl = strlen($params['key'])) < 16) + { + $params['key'] .= str_repeat("\x0", 16 - $kl); + } + + if (mcrypt_generic_init($params['handle'], $params['key'], $params['iv']) < 0) + { + if ($params['handle'] !== $this->_handle) + { + mcrypt_module_close($params['handle']); + } + + return FALSE; + } + + // Use PKCS#7 padding in order to ensure compatibility with OpenSSL + // and other implementations outside of PHP. + if (in_array(strtolower(mcrypt_enc_get_modes_name($params['handle'])), array('cbc', 'ecb'), TRUE)) + { + $block_size = mcrypt_enc_get_block_size($params['handle']); + $pad = $block_size - (strlen($data) % $block_size); + $data .= str_repeat(chr($pad), $pad); + } + + // Work-around for yet another strange behavior in MCrypt. + // + // When encrypting in ECB mode, the IV is ignored. Yet + // mcrypt_enc_get_iv_size() returns a value larger than 0 + // even if ECB is used AND mcrypt_generic_init() complains + // if you don't pass an IV with length equal to the said + // return value. + // + // This probably would've been fine (even though still wasteful), + // but OpenSSL isn't that dumb and we need to make the process + // portable, so ... + $data = (mcrypt_enc_get_modes_name($params['handle']) !== 'ECB') + ? $params['iv'].mcrypt_generic($params['handle'], $data) + : mcrypt_generic($params['handle'], $data); + + mcrypt_generic_deinit($params['handle']); + if ($params['handle'] !== $this->_handle) + { + mcrypt_module_close($params['handle']); + } + + return $data; + } + + // -------------------------------------------------------------------- + + /** + * Encrypt via OpenSSL + * + * @param string $data Input data + * @param array $params Input parameters + * @return string + */ + protected function _openssl_encrypt($data, $params) + { + if (empty($params['handle'])) + { + return FALSE; + } + elseif ( ! isset($params['iv'])) + { + $params['iv'] = ($iv_size = openssl_cipher_iv_length($params['handle'])) + ? openssl_random_pseudo_bytes($iv_size) + : NULL; + } + + $data = openssl_encrypt( + $data, + $params['handle'], + $params['key'], + 1, // DO NOT TOUCH! + $params['iv'] + ); + + if ($data === FALSE) + { + return FALSE; + } + + return $params['iv'].$data; + } + + // -------------------------------------------------------------------- + + /** + * Decrypt + * + * @param string $data Encrypted data + * @param array $params Input parameters + * @return string + */ + public function decrypt($data, array $params = NULL) + { + if (($params = $this->_get_params($params)) === FALSE) + { + return FALSE; + } + + if (isset($params['hmac_digest'])) + { + // This might look illogical, but it is done during encryption as well ... + // The 'base64' value is effectively an inverted "raw data" parameter + $digest_size = ($params['base64']) + ? $this->_digests[$params['hmac_digest']] * 2 + : $this->_digests[$params['hmac_digest']]; + + if (strlen($data) <= $digest_size) + { + return FALSE; + } + + $hmac_input = substr($data, 0, $digest_size); + $data = substr($data, $digest_size); + + isset($params['hmac_key']) OR $params['hmac_key'] = $this->hkdf($this->_key, 'sha512', NULL, NULL, 'authentication'); + $hmac_check = hash_hmac($params['hmac_digest'], $data, $params['hmac_key'], ! $params['base64']); + + // Time-attack-safe comparison + $diff = 0; + for ($i = 0; $i < $digest_size; $i++) + { + $diff |= ord($hmac_input[$i]) ^ ord($hmac_check[$i]); + } + + if ($diff !== 0) + { + return FALSE; + } + } + + if ($params['base64']) + { + $data = base64_decode($data); + } + + if (isset($params['iv']) && strncmp($params['iv'], $data, $iv_size = strlen($params['iv'])) === 0) + { + $data = substr($data, $iv_size); + } + + isset($params['key']) OR $params['key'] = $this->hkdf($this->_key, 'sha512', NULL, strlen($this->_key), 'encryption'); + + return $this->{'_'.$this->_driver.'_decrypt'}($data, $params); + } + + // -------------------------------------------------------------------- + + /** + * Decrypt via MCrypt + * + * @param string $data Encrypted data + * @param array $params Input parameters + * @return string + */ + protected function _mcrypt_decrypt($data, $params) + { + if ( ! is_resource($params['handle'])) + { + return FALSE; + } + elseif ( ! isset($params['iv'])) + { + // The greater-than-1 comparison is mostly a work-around for a bug, + // where 1 is returned for ARCFour instead of 0. + if (($iv_size = mcrypt_enc_get_iv_size($params['handle'])) > 1) + { + if (mcrypt_enc_get_modes_name($params['handle']) !== 'ECB') + { + $params['iv'] = substr($data, 0, $iv_size); + $data = substr($data, $iv_size); + } + else + { + // MCrypt is dumb and this is ignored, only size matters + $params['iv'] = str_repeat("\x0", $iv_size); + } + } + else + { + $params['iv'] = NULL; + } + } + + // CAST-128 compatibility (http://tools.ietf.org/rfc/rfc2144.txt) + // + // RFC2144 says that keys shorter than 16 bytes are to be padded with + // zero bytes to 16 bytes, but (surprise) MCrypt doesn't do that. + if ($params['cipher'] === 'cast-128' && ($kl = strlen($params['key'])) < 16) + { + $params['key'] .= str_repeat("\x0", 16 - $kl); + } + + if (mcrypt_generic_init($params['handle'], $params['key'], $params['iv']) < 0) + { + if ($params['handle'] !== $this->_handle) + { + mcrypt_module_close($params['handle']); + } + + return FALSE; + } + + $data = mdecrypt_generic($params['handle'], $data); + // Remove PKCS#7 padding, if necessary + if (in_array(strtolower(mcrypt_enc_get_modes_name($params['handle'])), array('cbc', 'ecb'), TRUE)) + { + $data = substr($data, 0, -ord($data[strlen($data)-1])); + } + + mcrypt_generic_deinit($params['handle']); + if ($params['handle'] !== $this->_handle) + { + mcrypt_module_close($params['handle']); + } + + return $data; + } + + // -------------------------------------------------------------------- + + /** + * Decrypt via OpenSSL + * + * @param string $data Encrypted data + * @param array $params Input parameters + * @return string + */ + protected function _openssl_decrypt($data, $params) + { + if ( ! isset($params['iv'])) + { + if ($iv_size = openssl_cipher_iv_length($params['handle'])) + { + $params['iv'] = substr($data, 0, $iv_size); + $data = substr($data, $iv_size); + } + else + { + $params['iv'] = NULL; + } + } + + return empty($params['handle']) + ? FALSE + : openssl_decrypt( + $data, + $params['handle'], + $params['key'], + 1, // DO NOT TOUCH! + $params['iv'] + ); + } + + // -------------------------------------------------------------------- + + /** + * Get params + * + * @param array $params Input parameters + * @return array + */ + protected function _get_params($params) + { + if (empty($params)) + { + return isset($this->_cipher, $this->_mode, $this->_key, $this->_handle) + ? array( + 'handle' => $this->_handle, + 'cipher' => $this->_cipher, + 'mode' => $this->_mode, + 'key' => NULL, + 'base64' => TRUE, + 'hmac_digest' => ($this->_mode !== 'gcm' ? 'sha512' : NULL), + 'hmac_key' => NULL + ) + : FALSE; + } + elseif ( ! isset($params['cipher'], $params['mode'], $params['key'])) + { + return FALSE; + } + + if (isset($params['mode'])) + { + $params['mode'] = strtolower($params['mode']); + if ( ! isset($this->_modes[$this->_driver][$params['mode']])) + { + return FALSE; + } + else + { + $params['mode'] = $this->_modes[$this->_driver][$params['mode']]; + } + } + + if ($params['mode'] === 'gcm' OR (isset($params['hmac']) && $params['hmac'] === FALSE)) + { + $params['hmac_digest'] = $params['hmac_key'] = NULL; + } + else + { + if ( ! isset($params['hmac_key'])) + { + return FALSE; + } + elseif (isset($params['hmac_digest'])) + { + $params['hmac_digest'] = strtolower($params['hmac_digest']); + if ( ! isset($this->_digests[$params['hmac_digest']])) + { + return FALSE; + } + } + else + { + $params['hmac_digest'] = 'sha512'; + } + } + + $params = array( + 'handle' => NULL, + 'cipher' => $params['cipher'], + 'mode' => $params['mode'], + 'key' => $params['key'], + 'iv' => isset($params['iv']) ? $params['iv'] : NULL, + 'base64' => isset($params['raw_data']) ? ! $params['raw_data'] : FALSE, + 'hmac_digest' => $params['hmac_digest'], + 'hmac_key' => $params['hmac_key'] + ); + + $this->_cipher_alias($params['cipher']); + $params['handle'] = ($params['cipher'] !== $this->_cipher OR $params['mode'] !== $this->_mode) + ? $this->{'_'.$this->_driver.'_get_handle'}($params['cipher'], $params['mode']) + : $this->_handle; + + return $params; + } + + // -------------------------------------------------------------------- + + /** + * Get MCrypt handle + * + * @param string $cipher Cipher name + * @param string $mode Encryption mode + * @return resource + */ + protected function _mcrypt_get_handle($cipher, $mode) + { + return mcrypt_module_open($cipher, '', $mode, ''); + } + + // -------------------------------------------------------------------- + + /** + * Get OpenSSL handle + * + * @param string $cipher Cipher name + * @param string $mode Encryption mode + * @return string + */ + protected function _openssl_get_handle($cipher, $mode) + { + // OpenSSL methods aren't suffixed with '-stream' for this mode + return ($mode === 'stream') + ? $cipher + : $cipher.'-'.$mode; + } + + // -------------------------------------------------------------------- + + /** + * Cipher alias + * + * Tries to translate cipher names between MCrypt and OpenSSL's "dialects". + * + * @param string $cipher Cipher name + * @return void + */ + protected function _cipher_alias(&$cipher) + { + static $dictionary; + + if (empty($dictionary)) + { + $dictionary = array( + 'mcrypt' => array( + 'aes-128' => 'rijndael-128', + 'aes-192' => 'rijndael-128', + 'aes-256' => 'rijndael-128', + 'des3-ede3' => 'tripledes', + 'bf' => 'blowfish', + 'cast5' => 'cast-128', + 'rc4' => 'arcfour', + 'rc4-40' => 'arcfour' + ), + 'openssl' => array( + 'rijndael-128' => 'aes-128', + 'tripledes' => 'des-ede3', + 'blowfish' => 'bf', + 'cast-128' => 'cast5', + 'arcfour' => 'rc4-40', + 'rc4' => 'rc4-40' + ) + ); + + // Notes: + // + // - Rijndael-128 is, at the same time all three of AES-128, + // AES-192 and AES-256. The only difference between them is + // the key size. Rijndael-192, Rijndael-256 on the other hand + // also have different block sizes and are NOT AES-compatible. + // + // - Blowfish is said to be supporting key sizes between + // 4 and 56 bytes, but it appears that between MCrypt and + // OpenSSL, only those of 16 and more bytes are compatible. + // Also, don't know what MCrypt's 'blowfish-compat' is. + // + // - CAST-128/CAST5 produces a longer cipher when encrypted via + // OpenSSL, but (strangely enough) can be decrypted by either + // extension anyway. + // Also, RFC2144 says that the cipher supports key sizes + // between 5 and 16 bytes by the implementation actually + // zero-padding them to 16 bytes, but MCrypt doesn't do that. + // + // - RC4 (ARCFour) has a strange implementation under OpenSSL. + // Its 'rc4-40' cipher method seems to work flawlessly, yet + // there's another one, 'rc4' that only works with a 16-byte key. + // + // - DES is compatible, but doesn't need an alias. + // + // Other seemingly matching ciphers between MCrypt, OpenSSL: + // + // - RC2 is NOT compatible and only an obscure forum post + // confirms that it is MCrypt's fault. + } + + if (isset($dictionary[$this->_driver][$cipher])) + { + $cipher = $dictionary[$this->_driver][$cipher]; + } + } + + // -------------------------------------------------------------------- + + /** + * HKDF + * + * @link https://tools.ietf.org/rfc/rfc5869.txt + * @param $key Input key + * @param $digest A SHA-2 hashing algorithm + * @param $salt Optional salt + * @param $length Output length (defaults to the selected digest size) + * @param $info Optional context/application-specific info + * @return string A pseudo-random key + */ + public function hkdf($key, $digest = 'sha512', $salt = NULL, $length = NULL, $info = '') + { + if ( ! isset($this->_digests[$digest])) + { + return FALSE; + } + + if (empty($length) OR ! is_int($length)) + { + $length = $this->_digests[$digest]; + } + elseif ($length > (255 * $this->_digests[$digest])) + { + return FALSE; + } + + isset($salt) OR $salt = str_repeat("\0", $this->_digests[$digest]); + + $prk = hash_hmac($digest, $key, $salt, TRUE); + $key = ''; + for ($key_block = '', $block_index = 1; strlen($key) < $length; $block_index++) + { + $key_block = hash_hmac($digest, $key_block.$info.chr($block_index), $prk, TRUE); + $key .= $key_block; + } + + return substr($key, 0, $length); + } + + // -------------------------------------------------------------------- + + /** + * __get() magic + * + * @param string $key Property name + * @return mixed + */ + public function __get($key) + { + // Because aliases + if ($key === 'mode') + { + return array_search($this->_mode, $this->_modes[$this->_driver], TRUE); + } + elseif (in_array($key, array('cipher', 'driver', 'drivers', 'digests'), TRUE)) + { + return $this->{'_'.$key}; + } + + return NULL; + } + +} + +/* End of file Encryption.php */ +/* Location: ./system/libraries/Encryption.php */
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