1: <?php
2: /**
3: * Core Security
4: *
5: * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
6: * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
7: *
8: * Licensed under The MIT License
9: * For full copyright and license information, please see the LICENSE.txt
10: * Redistributions of files must retain the above copyright notice.
11: *
12: * @copyright Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
13: * @link http://cakephp.org CakePHP(tm) Project
14: * @package Cake.Utility
15: * @since CakePHP(tm) v .0.10.0.1233
16: * @license http://www.opensource.org/licenses/mit-license.php MIT License
17: */
18:
19: App::uses('String', 'Utility');
20:
21: /**
22: * Security Library contains utility methods related to security
23: *
24: * @package Cake.Utility
25: */
26: class Security {
27:
28: /**
29: * Default hash method
30: *
31: * @var string
32: */
33: public static $hashType = null;
34:
35: /**
36: * Default cost
37: *
38: * @var string
39: */
40: public static $hashCost = '10';
41:
42: /**
43: * Get allowed minutes of inactivity based on security level.
44: *
45: * @deprecated 3.0.0 Exists for backwards compatibility only, not used by the core
46: * @return int Allowed inactivity in minutes
47: */
48: public static function inactiveMins() {
49: switch (Configure::read('Security.level')) {
50: case 'high':
51: return 10;
52: case 'medium':
53: return 100;
54: case 'low':
55: default:
56: return 300;
57: }
58: }
59:
60: /**
61: * Generate authorization hash.
62: *
63: * @return string Hash
64: */
65: public static function generateAuthKey() {
66: return Security::hash(String::uuid());
67: }
68:
69: /**
70: * Validate authorization hash.
71: *
72: * @param string $authKey Authorization hash
73: * @return bool Success
74: */
75: public static function validateAuthKey($authKey) {
76: return true;
77: }
78:
79: /**
80: * Create a hash from string using given method or fallback on next available method.
81: *
82: * #### Using Blowfish
83: *
84: * - Creating Hashes: *Do not supply a salt*. Cake handles salt creation for
85: * you ensuring that each hashed password will have a *unique* salt.
86: * - Comparing Hashes: Simply pass the originally hashed password as the salt.
87: * The salt is prepended to the hash and php handles the parsing automagically.
88: * For convenience the `BlowfishPasswordHasher` class is available for use with
89: * the AuthComponent.
90: * - Do NOT use a constant salt for blowfish!
91: *
92: * Creating a blowfish/bcrypt hash:
93: *
94: * {{{
95: * $hash = Security::hash($password, 'blowfish');
96: * }}}
97: *
98: * @param string $string String to hash
99: * @param string $type Method to use (sha1/sha256/md5/blowfish)
100: * @param mixed $salt If true, automatically prepends the application's salt
101: * value to $string (Security.salt). If you are using blowfish the salt
102: * must be false or a previously generated salt.
103: * @return string Hash
104: * @link http://book.cakephp.org/2.0/en/core-utility-libraries/security.html#Security::hash
105: */
106: public static function hash($string, $type = null, $salt = false) {
107: if (empty($type)) {
108: $type = self::$hashType;
109: }
110: $type = strtolower($type);
111:
112: if ($type === 'blowfish') {
113: return self::_crypt($string, $salt);
114: }
115: if ($salt) {
116: if (!is_string($salt)) {
117: $salt = Configure::read('Security.salt');
118: }
119: $string = $salt . $string;
120: }
121:
122: if (!$type || $type === 'sha1') {
123: if (function_exists('sha1')) {
124: return sha1($string);
125: }
126: $type = 'sha256';
127: }
128:
129: if ($type === 'sha256' && function_exists('mhash')) {
130: return bin2hex(mhash(MHASH_SHA256, $string));
131: }
132:
133: if (function_exists('hash')) {
134: return hash($type, $string);
135: }
136: return md5($string);
137: }
138:
139: /**
140: * Sets the default hash method for the Security object. This affects all objects using
141: * Security::hash().
142: *
143: * @param string $hash Method to use (sha1/sha256/md5/blowfish)
144: * @return void
145: * @see Security::hash()
146: */
147: public static function setHash($hash) {
148: self::$hashType = $hash;
149: }
150:
151: /**
152: * Sets the cost for they blowfish hash method.
153: *
154: * @param int $cost Valid values are 4-31
155: * @return void
156: */
157: public static function setCost($cost) {
158: if ($cost < 4 || $cost > 31) {
159: trigger_error(__d(
160: 'cake_dev',
161: 'Invalid value, cost must be between %s and %s',
162: array(4, 31)
163: ), E_USER_WARNING);
164: return null;
165: }
166: self::$hashCost = $cost;
167: }
168:
169: /**
170: * Runs $text through a XOR cipher.
171: *
172: * *Note* This is not a cryptographically strong method and should not be used
173: * for sensitive data. Additionally this method does *not* work in environments
174: * where suhosin is enabled.
175: *
176: * Instead you should use Security::rijndael() when you need strong
177: * encryption.
178: *
179: * @param string $text Encrypted string to decrypt, normal string to encrypt
180: * @param string $key Key to use
181: * @return string Encrypted/Decrypted string
182: * @deprecated 3.0.0 Will be removed in 3.0.
183: */
184: public static function cipher($text, $key) {
185: if (empty($key)) {
186: trigger_error(__d('cake_dev', 'You cannot use an empty key for %s', 'Security::cipher()'), E_USER_WARNING);
187: return '';
188: }
189:
190: srand(Configure::read('Security.cipherSeed'));
191: $out = '';
192: $keyLength = strlen($key);
193: for ($i = 0, $textLength = strlen($text); $i < $textLength; $i++) {
194: $j = ord(substr($key, $i % $keyLength, 1));
195: while ($j--) {
196: rand(0, 255);
197: }
198: $mask = rand(0, 255);
199: $out .= chr(ord(substr($text, $i, 1)) ^ $mask);
200: }
201: srand();
202: return $out;
203: }
204:
205: /**
206: * Encrypts/Decrypts a text using the given key using rijndael method.
207: *
208: * Prior to 2.3.1, a fixed initialization vector was used. This was not
209: * secure. This method now uses a random iv, and will silently upgrade values when
210: * they are re-encrypted.
211: *
212: * @param string $text Encrypted string to decrypt, normal string to encrypt
213: * @param string $key Key to use as the encryption key for encrypted data.
214: * @param string $operation Operation to perform, encrypt or decrypt
215: * @return string Encrypted/Decrypted string
216: */
217: public static function rijndael($text, $key, $operation) {
218: if (empty($key)) {
219: trigger_error(__d('cake_dev', 'You cannot use an empty key for %s', 'Security::rijndael()'), E_USER_WARNING);
220: return '';
221: }
222: if (empty($operation) || !in_array($operation, array('encrypt', 'decrypt'))) {
223: trigger_error(__d('cake_dev', 'You must specify the operation for Security::rijndael(), either encrypt or decrypt'), E_USER_WARNING);
224: return '';
225: }
226: if (strlen($key) < 32) {
227: trigger_error(__d('cake_dev', 'You must use a key larger than 32 bytes for Security::rijndael()'), E_USER_WARNING);
228: return '';
229: }
230: $algorithm = MCRYPT_RIJNDAEL_256;
231: $mode = MCRYPT_MODE_CBC;
232: $ivSize = mcrypt_get_iv_size($algorithm, $mode);
233:
234: $cryptKey = substr($key, 0, 32);
235:
236: if ($operation === 'encrypt') {
237: $iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
238: return $iv . '$$' . mcrypt_encrypt($algorithm, $cryptKey, $text, $mode, $iv);
239: }
240: // Backwards compatible decrypt with fixed iv
241: if (substr($text, $ivSize, 2) !== '$$') {
242: $iv = substr($key, strlen($key) - 32, 32);
243: return rtrim(mcrypt_decrypt($algorithm, $cryptKey, $text, $mode, $iv), "\0");
244: }
245: $iv = substr($text, 0, $ivSize);
246: $text = substr($text, $ivSize + 2);
247: return rtrim(mcrypt_decrypt($algorithm, $cryptKey, $text, $mode, $iv), "\0");
248: }
249:
250: /**
251: * Generates a pseudo random salt suitable for use with php's crypt() function.
252: * The salt length should not exceed 27. The salt will be composed of
253: * [./0-9A-Za-z]{$length}.
254: *
255: * @param int $length The length of the returned salt
256: * @return string The generated salt
257: */
258: protected static function _salt($length = 22) {
259: $salt = str_replace(
260: array('+', '='),
261: '.',
262: base64_encode(sha1(uniqid(Configure::read('Security.salt'), true), true))
263: );
264: return substr($salt, 0, $length);
265: }
266:
267: /**
268: * One way encryption using php's crypt() function. To use blowfish hashing see ``Security::hash()``
269: *
270: * @param string $password The string to be encrypted.
271: * @param mixed $salt false to generate a new salt or an existing salt.
272: * @return string The hashed string or an empty string on error.
273: */
274: protected static function _crypt($password, $salt = false) {
275: if ($salt === false) {
276: $salt = self::_salt(22);
277: $salt = vsprintf('$2a$%02d$%s', array(self::$hashCost, $salt));
278: }
279:
280: $invalidCipher = (
281: strpos($salt, '$2y$') !== 0 &&
282: strpos($salt, '$2x$') !== 0 &&
283: strpos($salt, '$2a$') !== 0
284: );
285: if ($salt === true || $invalidCipher || strlen($salt) < 29) {
286: trigger_error(__d(
287: 'cake_dev',
288: 'Invalid salt: %s for %s Please visit http://www.php.net/crypt and read the appropriate section for building %s salts.',
289: array($salt, 'blowfish', 'blowfish')
290: ), E_USER_WARNING);
291: return '';
292: }
293: return crypt($password, $salt);
294: }
295:
296: /**
297: * Encrypt a value using AES-256.
298: *
299: * *Caveat* You cannot properly encrypt/decrypt data with trailing null bytes.
300: * Any trailing null bytes will be removed on decryption due to how PHP pads messages
301: * with nulls prior to encryption.
302: *
303: * @param string $plain The value to encrypt.
304: * @param string $key The 256 bit/32 byte key to use as a cipher key.
305: * @param string $hmacSalt The salt to use for the HMAC process. Leave null to use Security.salt.
306: * @return string Encrypted data.
307: * @throws CakeException On invalid data or key.
308: */
309: public static function encrypt($plain, $key, $hmacSalt = null) {
310: self::_checkKey($key, 'encrypt()');
311:
312: if ($hmacSalt === null) {
313: $hmacSalt = Configure::read('Security.salt');
314: }
315:
316: // Generate the encryption and hmac key.
317: $key = substr(hash('sha256', $key . $hmacSalt), 0, 32);
318:
319: $algorithm = MCRYPT_RIJNDAEL_128;
320: $mode = MCRYPT_MODE_CBC;
321:
322: $ivSize = mcrypt_get_iv_size($algorithm, $mode);
323: $iv = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM);
324: $ciphertext = $iv . mcrypt_encrypt($algorithm, $key, $plain, $mode, $iv);
325: $hmac = hash_hmac('sha256', $ciphertext, $key);
326: return $hmac . $ciphertext;
327: }
328:
329: /**
330: * Check the encryption key for proper length.
331: *
332: * @param string $key Key to check.
333: * @param string $method The method the key is being checked for.
334: * @return void
335: * @throws CakeException When key length is not 256 bit/32 bytes
336: */
337: protected static function _checkKey($key, $method) {
338: if (strlen($key) < 32) {
339: throw new CakeException(__d('cake_dev', 'Invalid key for %s, key must be at least 256 bits (32 bytes) long.', $method));
340: }
341: }
342:
343: /**
344: * Decrypt a value using AES-256.
345: *
346: * @param string $cipher The ciphertext to decrypt.
347: * @param string $key The 256 bit/32 byte key to use as a cipher key.
348: * @param string $hmacSalt The salt to use for the HMAC process. Leave null to use Security.salt.
349: * @return string Decrypted data. Any trailing null bytes will be removed.
350: * @throws CakeException On invalid data or key.
351: */
352: public static function decrypt($cipher, $key, $hmacSalt = null) {
353: self::_checkKey($key, 'decrypt()');
354: if (empty($cipher)) {
355: throw new CakeException(__d('cake_dev', 'The data to decrypt cannot be empty.'));
356: }
357: if ($hmacSalt === null) {
358: $hmacSalt = Configure::read('Security.salt');
359: }
360:
361: // Generate the encryption and hmac key.
362: $key = substr(hash('sha256', $key . $hmacSalt), 0, 32);
363:
364: // Split out hmac for comparison
365: $macSize = 64;
366: $hmac = substr($cipher, 0, $macSize);
367: $cipher = substr($cipher, $macSize);
368:
369: $compareHmac = hash_hmac('sha256', $cipher, $key);
370: if ($hmac !== $compareHmac) {
371: return false;
372: }
373:
374: $algorithm = MCRYPT_RIJNDAEL_128;
375: $mode = MCRYPT_MODE_CBC;
376: $ivSize = mcrypt_get_iv_size($algorithm, $mode);
377:
378: $iv = substr($cipher, 0, $ivSize);
379: $cipher = substr($cipher, $ivSize);
380: $plain = mcrypt_decrypt($algorithm, $key, $cipher, $mode, $iv);
381: return rtrim($plain, "\0");
382: }
383:
384: }
385: