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ENHANCEMENT Added RandomGenerator for more secure CRSF tokens etc.

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@114497 467b73ca-7a2a-4603-9d3b-597d59a354a9
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chillu committed Dec 5, 2010
1 parent 6cec0a0 commit c378448f193c342cb4b797458fb45828eb7414ad
Showing with 90 additions and 0 deletions.
  1. +63 −0 security/RandomGenerator.php
  2. +27 −0 tests/security/RandomGeneratorTest.php
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+<?php
+/**
+ * Generates entropy values based on strongest available methods
+ * (mcrypt_create_iv(), openssl_random_pseudo_bytes(), /dev/urandom, COM.CAPICOM.Utilities.1, mt_rand()).
+ * Chosen method depends on operating system and PHP version.
+ *
+ * @package sapphire
+ * @subpackage security
+ * @author Ingo Schommer
+ */
+class RandomGenerator {
+
+ /**
+ * @return string Returns a random series of bytes
+ */
+ function generateEntropy() {
+ // mcrypt with urandom is only available on PHP 5.3 or newer
+ if(version_compare(PHP_VERSION, '5.3.0', '>=')) {
+ return mcrypt_create_iv(64, MCRYPT_DEV_URANDOM);
+ }
+
+ // Fall back to SSL methods - may slow down execution by a few ms
+ if (function_exists('openssl_random_pseudo_bytes')) {
+ $e = openssl_random_pseudo_bytes(64, $strong);
+ // Only return if strong algorithm was used
+ if($strong) return $e;
+ }
+
+ // Read from the unix random number generator
+ if (is_readable('/dev/urandom') && ($h = fopen('/dev/urandom', 'rb'))) {
+ $e = fread($h, 64);
+ fclose($h);
+ return $e;
+ }
+
+ // Warning: Both methods below are considered weak
+
+ // try to read from the windows RNG
+ if (class_exists('COM')) {
+ try {
+ $comObj = new COM('CAPICOM.Utilities.1');
+ $e = base64_decode($comObj->GetRandom(64, 0));
+ return $e;
+ } catch (Exception $ex) {
+ }
+ }
+
+ // Fallback to good old mt_rand()
+ return uniqid(mt_rand(), true);
+ }
+
+ /**
+ * Generates a hash suitable for manual session identifiers, CSRF tokens, etc.
+ *
+ * @param String $algorithm Any identifier listed in hash_algos() (Default: whirlpool)
+ * If possible, choose a slow algorithm which complicates brute force attacks.
+ * @return String Returned length will depend on the used $algorithm
+ */
+ function generateHash($algorithm = 'whirlpool') {
+ return hash($algorithm, $this->generateEntropy());
+ }
+
+}
@@ -0,0 +1,27 @@
+<?php
+/**
+ * @package sapphire
+ * @subpackage tests
+ * @author Ingo Schommer
+ */
+class RandomGeneratorTest extends SapphireTest {
+
+ function testGenerateEntropy() {
+ $r = new RandomGenerator();
+ $this->assertNotNull($r->generateEntropy());
+ $this->assertNotEquals($r->generateEntropy(), $r->generateEntropy());
+ }
+
+ function testGenerateHash() {
+ $r = new RandomGenerator();
+ $this->assertNotNull($r->generateHash());
+ $this->assertNotEquals($r->generateHash(), $r->generateHash());
+ }
+
+ function testGenerateHashWithAlgorithm() {
+ $r = new RandomGenerator();
+ $this->assertNotNull($r->generateHash('md5'));
+ $this->assertNotEquals($r->generateHash(), $r->generateHash('md5'));
+ }
+
+}

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