mirror of https://github.com/MISP/MISP
58 lines
2.2 KiB
PHP
58 lines
2.2 KiB
PHP
<?php
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class RandomTool
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{
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/**
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* Generate a random string
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*
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* Generate a random string, using a cryptographically secure
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* pseudorandom number generator (random_int)
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*
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* For PHP 7, random_int is a PHP core function
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* For PHP 5.x, depends on https://github.com/paragonie/random_compat
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*
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* @link https://paragonie.com/b/JvICXzh_jhLyt4y3
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*
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* @param bool $crypto_secure - If a cryptographically secure or a fast random number generator should be used
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* @param int $length - How long should our random string be?
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* @param string $charset - A string of all possible characters to choose from
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* @return string
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* @throws Exception
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*/
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public function random_str($crypto_secure = true, $length = 32, $charset = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')
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{
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// Type checks:
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if (!is_bool($crypto_secure)) {
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throw new InvalidArgumentException('random_str - Argument 1 - expected a boolean');
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}
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if (!is_numeric($length)) {
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throw new InvalidArgumentException('random_str - Argument 2 - expected an integer');
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}
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if (!is_string($charset)) {
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throw new InvalidArgumentException('random_str - Argument 3 - expected a string');
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}
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if ($length < 1) {
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// Just return an empty string. Any value < 1 is meaningless.
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return '';
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}
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// Remove duplicate characters from $charset
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$charset = count_chars($charset, 3);
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// This is the maximum index for all of the characters in the string $charset
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$charset_max = strlen($charset) - 1;
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if ($charset_max < 1) {
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// Avoid letting users do: random_str($int, 'a'); -> 'aaaaa...'
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throw new LogicException('random_str - Argument 3 - expected a string that contains at least 2 distinct characters');
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}
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// Now that we have good data, this is the meat of our function:
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$random_str = '';
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for ($i = 0; $i < $length; ++$i) {
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$r = $crypto_secure ? random_int(0, $charset_max) : mt_rand(0, $charset_max);
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$random_str .= $charset[$r];
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}
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return $random_str;
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}
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}
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