worker / lib / PHPSecLib / Crypt / Random.php

Random.php in ManageWP Worker 3.9.28, at lib/PHPSecLib/Crypt/Random.php

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1	<?php
2	/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */
3
4	/**
5	* Random Number Generator
6	*
7	* PHP versions 4 and 5
8	*
9	* Here's a short example of how to use this library:
10	* <code>
11	* <?php
12	* include('Crypt/Random.php');
13	*
14	* echo bin2hex(crypt_random_string(8));
15	* ?>
16	* </code>
17	*
18	* LICENSE: Permission is hereby granted, free of charge, to any person obtaining a copy
19	* of this software and associated documentation files (the "Software"), to deal
20	* in the Software without restriction, including without limitation the rights
21	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
22	* copies of the Software, and to permit persons to whom the Software is
23	* furnished to do so, subject to the following conditions:
24	*
25	* The above copyright notice and this permission notice shall be included in
26	* all copies or substantial portions of the Software.
27	*
28	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
29	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
30	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
31	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
32	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
33	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
34	* THE SOFTWARE.
35	*
36	* @category Crypt
37	* @package Crypt_Random
38	* @author Jim Wigginton <terrafrost@php.net>
39	* @copyright MMVII Jim Wigginton
40	* @license http://www.opensource.org/licenses/mit-license.html MIT License
41	* @link http://phpseclib.sourceforge.net
42	*/
43
44	/**
45	* "Is Windows" test
46	*
47	* @access private
48	*/
49	define('CRYPT_RANDOM_IS_WINDOWS', strtoupper(substr(PHP_OS, 0, 3)) === 'WIN');
50
51	/**
52	* Generate a random string.
53	*
54	* Although microoptimizations are generally discouraged as they impair readability this function is ripe with
55	* microoptimizations because this function has the potential of being called a huge number of times.
56	* eg. for RSA key generation.
57	*
58	* @param Integer $length
59	* @return String
60	* @access public
61	*/
62	function crypt_random_string($length)
63	{
64	if (CRYPT_RANDOM_IS_WINDOWS) {
65	// method 1. prior to PHP 5.3 this would call rand() on windows hence the function_exists('class_alias') call.
66	// ie. class_alias is a function that was introduced in PHP 5.3
67	if (function_exists('mcrypt_create_iv') && function_exists('class_alias')) {
68	return mcrypt_create_iv($length);
69	}
70	// method 2. openssl_random_pseudo_bytes was introduced in PHP 5.3.0 but prior to PHP 5.3.4 there was,
71	// to quote <http://php.net/ChangeLog-5.php#5.3.4>, "possible blocking behavior". as of 5.3.4
72	// openssl_random_pseudo_bytes and mcrypt_create_iv do the exact same thing on Windows. ie. they both
73	// call php_win32_get_random_bytes():
74	//
75	// https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/openssl/openssl.c#L5008
76	// https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/mcrypt/mcrypt.c#L1392
77	//
78	// php_win32_get_random_bytes() is defined thusly:
79	//
80	// https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/win32/winutil.c#L80
81	//
82	// we're calling it, all the same, in the off chance that the mcrypt extension is not available
83	if (function_exists('openssl_random_pseudo_bytes') && version_compare(PHP_VERSION, '5.3.4', '>=')) {
84	return openssl_random_pseudo_bytes($length);
85	}
86	} else {
87	// method 1. the fastest
88	if (function_exists('openssl_random_pseudo_bytes')) {
89	return openssl_random_pseudo_bytes($length);
90	}
91	// method 2
92	static $fp = true;
93	if ($fp === true) {
94	// warning's will be output unles the error suppression operator is used. errors such as
95	// "open_basedir restriction in effect", "Permission denied", "No such file or directory", etc.
96	$fp = @fopen('/dev/urandom', 'rb');
97	}
98	if ($fp !== true && $fp !== false) { // surprisingly faster than !is_bool() or is_resource()
99	return fread($fp, $length);
100	}
101	// method 3. pretty much does the same thing as method 2 per the following url:
102	// https://github.com/php/php-src/blob/7014a0eb6d1611151a286c0ff4f2238f92c120d6/ext/mcrypt/mcrypt.c#L1391
103	// surprisingly slower than method 2. maybe that's because mcrypt_create_iv does a bunch of error checking that we're
104	// not doing. regardless, this'll only be called if this PHP script couldn't open /dev/urandom due to open_basedir
105	// restrictions or some such
106	if (function_exists('mcrypt_create_iv')) {
107	return mcrypt_create_iv($length, MCRYPT_DEV_URANDOM);
108	}
109	}
110	// at this point we have no choice but to use a pure-PHP CSPRNG
111
112	// cascade entropy across multiple PHP instances by fixing the session and collecting all
113	// environmental variables, including the previous session data and the current session
114	// data.
115	//
116	// mt_rand seeds itself by looking at the PID and the time, both of which are (relatively)
117	// easy to guess at. linux uses mouse clicks, keyboard timings, etc, as entropy sources, but
118	// PHP isn't low level to be able to use those as sources and on a web server there's not likely
119	// going to be a ton of keyboard or mouse action. web servers do have one thing that we can use
120	// however. a ton of people visiting the website. obviously you don't want to base your seeding
121	// soley on parameters a potential attacker sends but (1) not everything in $_SERVER is controlled
122	// by the user and (2) this isn't just looking at the data sent by the current user - it's based
123	// on the data sent by all users. one user requests the page and a hash of their info is saved.
124	// another user visits the page and the serialization of their data is utilized along with the
125	// server envirnment stuff and a hash of the previous http request data (which itself utilizes
126	// a hash of the session data before that). certainly an attacker should be assumed to have
127	// full control over his own http requests. he, however, is not going to have control over
128	// everyone's http requests.
129	static $crypto = false, $v;
130	if ($crypto === false) {
131	// save old session data
132	$old_session_id = session_id();
133	$old_use_cookies = ini_get('session.use_cookies');
134	$old_session_cache_limiter = session_cache_limiter();
135	if (isset($_SESSION)) {
136	$_OLD_SESSION = $_SESSION;
137	}
138	if ($old_session_id != '') {
139	session_write_close();
140	}
141
142	session_id(1);
143	ini_set('session.use_cookies', 0);
144	session_cache_limiter('');
145	session_start();
146
147	$v = $seed = $_SESSION['seed'] = pack('H*', sha1(
148	serialize($_SERVER) .
149	serialize($_POST) .
150	serialize($_GET) .
151	serialize($_COOKIE) .
152	serialize($GLOBALS) .
153	serialize($_SESSION) .
154	serialize($_OLD_SESSION)
155	));
156	if (!isset($_SESSION['count'])) {
157	$_SESSION['count'] = 0;
158	}
159	$_SESSION['count']++;
160
161	session_write_close();
162
163	// restore old session data
164	if ($old_session_id != '') {
165	session_id($old_session_id);
166	session_start();
167	ini_set('session.use_cookies', $old_use_cookies);
168	session_cache_limiter($old_session_cache_limiter);
169	} else {
170	if (isset($_OLD_SESSION)) {
171	$_SESSION = $_OLD_SESSION;
172	unset($_OLD_SESSION);
173	} else {
174	unset($_SESSION);
175	}
176	}
177
178	// in SSH2 a shared secret and an exchange hash are generated through the key exchange process.
179	// the IV client to server is the hash of that "nonce" with the letter A and for the encryption key it's the letter C.
180	// if the hash doesn't produce enough a key or an IV that's long enough concat successive hashes of the
181	// original hash and the current hash. we'll be emulating that. for more info see the following URL:
182	//
183	// http://tools.ietf.org/html/rfc4253#section-7.2
184	//
185	// see the is_string($crypto) part for an example of how to expand the keys
186	$key = pack('H*', sha1($seed . 'A'));
187	$iv = pack('H*', sha1($seed . 'C'));
188
189	// ciphers are used as per the nist.gov link below. also, see this link:
190	//
191	// http://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator#Designs_based_on_cryptographic_primitives
192	switch (true) {
193	case class_exists('Crypt_AES'):
194	$crypto = new Crypt_AES(CRYPT_AES_MODE_CTR);
195	break;
196	case class_exists('Crypt_TripleDES'):
197	$crypto = new Crypt_TripleDES(CRYPT_DES_MODE_CTR);
198	break;
199	case class_exists('Crypt_DES'):
200	$crypto = new Crypt_DES(CRYPT_DES_MODE_CTR);
201	break;
202	case class_exists('Crypt_RC4'):
203	$crypto = new Crypt_RC4();
204	break;
205	default:
206	$crypto = $seed;
207	return crypt_random_string($length);
208	}
209
210	$crypto->setKey($key);
211	$crypto->setIV($iv);
212	$crypto->enableContinuousBuffer();
213	}
214
215	if (is_string($crypto)) {
216	// the following is based off of ANSI X9.31:
217	//
218	// http://csrc.nist.gov/groups/STM/cavp/documents/rng/931rngext.pdf
219	//
220	// OpenSSL uses that same standard for it's random numbers:
221	//
222	// http://www.opensource.apple.com/source/OpenSSL/OpenSSL-38/openssl/fips-1.0/rand/fips_rand.c
223	// (do a search for "ANS X9.31 A.2.4")
224	//
225	// ANSI X9.31 recommends ciphers be used and phpseclib does use them if they're available (see
226	// later on in the code) but if they're not we'll use sha1
227	$result = '';
228	while (strlen($result) < $length) { // each loop adds 20 bytes
229	// microtime() isn't packed as "densely" as it could be but then neither is that the idea.
230	// the idea is simply to ensure that each "block" has a unique element to it.
231	$i = pack('H*', sha1(microtime()));
232	$r = pack('H*', sha1($i ^ $v));
233	$v = pack('H*', sha1($r ^ $i));
234	$result.= $r;
235	}
236	return substr($result, 0, $length);
237	}
238
239	//return $crypto->encrypt(str_repeat("\0", $length));
240
241	$result = '';
242	while (strlen($result) < $length) {
243	$i = $crypto->encrypt(microtime());
244	$r = $crypto->encrypt($i ^ $v);
245	$v = $crypto->encrypt($r ^ $i);
246	$result.= $r;
247	}
248	return substr($result, 0, $length);
249	}
250