diff options
author | Pierre Schmitz <pierre@archlinux.de> | 2014-12-27 15:41:37 +0100 |
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committer | Pierre Schmitz <pierre@archlinux.de> | 2014-12-31 11:43:28 +0100 |
commit | c1f9b1f7b1b77776192048005dcc66dcf3df2bfb (patch) | |
tree | 2b38796e738dd74cb42ecd9bfd151803108386bc /includes/MWCryptRand.php | |
parent | b88ab0086858470dd1f644e64cb4e4f62bb2be9b (diff) |
Update to MediaWiki 1.24.1
Diffstat (limited to 'includes/MWCryptRand.php')
-rw-r--r-- | includes/MWCryptRand.php | 497 |
1 files changed, 0 insertions, 497 deletions
diff --git a/includes/MWCryptRand.php b/includes/MWCryptRand.php deleted file mode 100644 index bac018e8..00000000 --- a/includes/MWCryptRand.php +++ /dev/null @@ -1,497 +0,0 @@ -<?php -/** - * A cryptographic random generator class used for generating secret keys - * - * This is based in part on Drupal code as well as what we used in our own code - * prior to introduction of this class. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. - * http://www.gnu.org/copyleft/gpl.html - * - * @author Daniel Friesen - * @file - */ - -class MWCryptRand { - - /** - * Minimum number of iterations we want to make in our drift calculations. - */ - const MIN_ITERATIONS = 1000; - - /** - * Number of milliseconds we want to spend generating each separate byte - * of the final generated bytes. - * This is used in combination with the hash length to determine the duration - * we should spend doing drift calculations. - */ - const MSEC_PER_BYTE = 0.5; - - /** - * Singleton instance for public use - */ - protected static $singleton = null; - - /** - * The hash algorithm being used - */ - protected $algo = null; - - /** - * The number of bytes outputted by the hash algorithm - */ - protected $hashLength = null; - - /** - * A boolean indicating whether the previous random generation was done using - * cryptographically strong random number generator or not. - */ - protected $strong = null; - - /** - * Initialize an initial random state based off of whatever we can find - */ - protected function initialRandomState() { - // $_SERVER contains a variety of unstable user and system specific information - // It'll vary a little with each page, and vary even more with separate users - // It'll also vary slightly across different machines - $state = serialize( $_SERVER ); - - // To try vary the system information of the state a bit more - // by including the system's hostname into the state - $state .= wfHostname(); - - // Try to gather a little entropy from the different php rand sources - $state .= rand() . uniqid( mt_rand(), true ); - - // Include some information about the filesystem's current state in the random state - $files = array(); - - // We know this file is here so grab some info about ourselves - $files[] = __FILE__; - - // We must also have a parent folder, and with the usual file structure, a grandparent - $files[] = __DIR__; - $files[] = dirname( __DIR__ ); - - // The config file is likely the most often edited file we know should be around - // so include its stat info into the state. - // The constant with its location will almost always be defined, as WebStart.php defines - // MW_CONFIG_FILE to $IP/LocalSettings.php unless being configured with MW_CONFIG_CALLBACK (eg. the installer) - if ( defined( 'MW_CONFIG_FILE' ) ) { - $files[] = MW_CONFIG_FILE; - } - - foreach ( $files as $file ) { - wfSuppressWarnings(); - $stat = stat( $file ); - wfRestoreWarnings(); - if ( $stat ) { - // stat() duplicates data into numeric and string keys so kill off all the numeric ones - foreach ( $stat as $k => $v ) { - if ( is_numeric( $k ) ) { - unset( $k ); - } - } - // The absolute filename itself will differ from install to install so don't leave it out - if ( ( $path = realpath( $file ) ) !== false ) { - $state .= $path; - } else { - $state .= $file; - } - $state .= implode( '', $stat ); - } else { - // The fact that the file isn't there is worth at least a - // minuscule amount of entropy. - $state .= '0'; - } - } - - // Try and make this a little more unstable by including the varying process - // id of the php process we are running inside of if we are able to access it - if ( function_exists( 'getmypid' ) ) { - $state .= getmypid(); - } - - // If available try to increase the instability of the data by throwing in - // the precise amount of memory that we happen to be using at the moment. - if ( function_exists( 'memory_get_usage' ) ) { - $state .= memory_get_usage( true ); - } - - // It's mostly worthless but throw the wiki's id into the data for a little more variance - $state .= wfWikiID(); - - // If we have a secret key or proxy key set then throw it into the state as well - global $wgSecretKey, $wgProxyKey; - if ( $wgSecretKey ) { - $state .= $wgSecretKey; - } elseif ( $wgProxyKey ) { - $state .= $wgProxyKey; - } - - return $state; - } - - /** - * Randomly hash data while mixing in clock drift data for randomness - * - * @param string $data The data to randomly hash. - * @return String The hashed bytes - * @author Tim Starling - */ - protected function driftHash( $data ) { - // Minimum number of iterations (to avoid slow operations causing the loop to gather little entropy) - $minIterations = self::MIN_ITERATIONS; - // Duration of time to spend doing calculations (in seconds) - $duration = ( self::MSEC_PER_BYTE / 1000 ) * $this->hashLength(); - // Create a buffer to use to trigger memory operations - $bufLength = 10000000; - $buffer = str_repeat( ' ', $bufLength ); - $bufPos = 0; - - // Iterate for $duration seconds or at least $minIterations number of iterations - $iterations = 0; - $startTime = microtime( true ); - $currentTime = $startTime; - while ( $iterations < $minIterations || $currentTime - $startTime < $duration ) { - // Trigger some memory writing to trigger some bus activity - // This may create variance in the time between iterations - $bufPos = ( $bufPos + 13 ) % $bufLength; - $buffer[$bufPos] = ' '; - // Add the drift between this iteration and the last in as entropy - $nextTime = microtime( true ); - $delta = (int)( ( $nextTime - $currentTime ) * 1000000 ); - $data .= $delta; - // Every 100 iterations hash the data and entropy - if ( $iterations % 100 === 0 ) { - $data = sha1( $data ); - } - $currentTime = $nextTime; - $iterations++; - } - $timeTaken = $currentTime - $startTime; - $data = $this->hash( $data ); - - wfDebug( __METHOD__ . ": Clock drift calculation " . - "(time-taken=" . ( $timeTaken * 1000 ) . "ms, " . - "iterations=$iterations, " . - "time-per-iteration=" . ( $timeTaken / $iterations * 1e6 ) . "us)\n" ); - return $data; - } - - /** - * Return a rolling random state initially build using data from unstable sources - * @return string A new weak random state - */ - protected function randomState() { - static $state = null; - if ( is_null( $state ) ) { - // Initialize the state with whatever unstable data we can find - // It's important that this data is hashed right afterwards to prevent - // it from being leaked into the output stream - $state = $this->hash( $this->initialRandomState() ); - } - // Generate a new random state based on the initial random state or previous - // random state by combining it with clock drift - $state = $this->driftHash( $state ); - return $state; - } - - /** - * Decide on the best acceptable hash algorithm we have available for hash() - * @throws MWException - * @return String A hash algorithm - */ - protected function hashAlgo() { - if ( !is_null( $this->algo ) ) { - return $this->algo; - } - - $algos = hash_algos(); - $preference = array( 'whirlpool', 'sha256', 'sha1', 'md5' ); - - foreach ( $preference as $algorithm ) { - if ( in_array( $algorithm, $algos ) ) { - $this->algo = $algorithm; - wfDebug( __METHOD__ . ": Using the {$this->algo} hash algorithm.\n" ); - return $this->algo; - } - } - - // We only reach here if no acceptable hash is found in the list, this should - // be a technical impossibility since most of php's hash list is fixed and - // some of the ones we list are available as their own native functions - // But since we already require at least 5.2 and hash() was default in - // 5.1.2 we don't bother falling back to methods like sha1 and md5. - throw new MWException( "Could not find an acceptable hashing function in hash_algos()" ); - } - - /** - * Return the byte-length output of the hash algorithm we are - * using in self::hash and self::hmac. - * - * @return int Number of bytes the hash outputs - */ - protected function hashLength() { - if ( is_null( $this->hashLength ) ) { - $this->hashLength = strlen( $this->hash( '' ) ); - } - return $this->hashLength; - } - - /** - * Generate an acceptably unstable one-way-hash of some text - * making use of the best hash algorithm that we have available. - * - * @param $data string - * @return String A raw hash of the data - */ - protected function hash( $data ) { - return hash( $this->hashAlgo(), $data, true ); - } - - /** - * Generate an acceptably unstable one-way-hmac of some text - * making use of the best hash algorithm that we have available. - * - * @param $data string - * @param $key string - * @return String A raw hash of the data - */ - protected function hmac( $data, $key ) { - return hash_hmac( $this->hashAlgo(), $data, $key, true ); - } - - /** - * @see self::wasStrong() - */ - public function realWasStrong() { - if ( is_null( $this->strong ) ) { - throw new MWException( __METHOD__ . ' called before generation of random data' ); - } - return $this->strong; - } - - /** - * @see self::generate() - */ - public function realGenerate( $bytes, $forceStrong = false ) { - wfProfileIn( __METHOD__ ); - - wfDebug( __METHOD__ . ": Generating cryptographic random bytes for " . wfGetAllCallers( 5 ) . "\n" ); - - $bytes = floor( $bytes ); - static $buffer = ''; - if ( is_null( $this->strong ) ) { - // Set strength to false initially until we know what source data is coming from - $this->strong = true; - } - - if ( strlen( $buffer ) < $bytes ) { - // If available make use of mcrypt_create_iv URANDOM source to generate randomness - // On unix-like systems this reads from /dev/urandom but does it without any buffering - // and bypasses openbasedir restrictions, so it's preferable to reading directly - // On Windows starting in PHP 5.3.0 Windows' native CryptGenRandom is used to generate - // entropy so this is also preferable to just trying to read urandom because it may work - // on Windows systems as well. - if ( function_exists( 'mcrypt_create_iv' ) ) { - wfProfileIn( __METHOD__ . '-mcrypt' ); - $rem = $bytes - strlen( $buffer ); - $iv = mcrypt_create_iv( $rem, MCRYPT_DEV_URANDOM ); - if ( $iv === false ) { - wfDebug( __METHOD__ . ": mcrypt_create_iv returned false.\n" ); - } else { - $buffer .= $iv; - wfDebug( __METHOD__ . ": mcrypt_create_iv generated " . strlen( $iv ) . " bytes of randomness.\n" ); - } - wfProfileOut( __METHOD__ . '-mcrypt' ); - } - } - - if ( strlen( $buffer ) < $bytes ) { - // If available make use of openssl's random_pseudo_bytes method to attempt to generate randomness. - // However don't do this on Windows with PHP < 5.3.4 due to a bug: - // http://stackoverflow.com/questions/1940168/openssl-random-pseudo-bytes-is-slow-php - // http://git.php.net/?p=php-src.git;a=commitdiff;h=cd62a70863c261b07f6dadedad9464f7e213cad5 - if ( function_exists( 'openssl_random_pseudo_bytes' ) - && ( !wfIsWindows() || version_compare( PHP_VERSION, '5.3.4', '>=' ) ) - ) { - wfProfileIn( __METHOD__ . '-openssl' ); - $rem = $bytes - strlen( $buffer ); - $openssl_bytes = openssl_random_pseudo_bytes( $rem, $openssl_strong ); - if ( $openssl_bytes === false ) { - wfDebug( __METHOD__ . ": openssl_random_pseudo_bytes returned false.\n" ); - } else { - $buffer .= $openssl_bytes; - wfDebug( __METHOD__ . ": openssl_random_pseudo_bytes generated " . strlen( $openssl_bytes ) . " bytes of " . ( $openssl_strong ? "strong" : "weak" ) . " randomness.\n" ); - } - if ( strlen( $buffer ) >= $bytes ) { - // openssl tells us if the random source was strong, if some of our data was generated - // using it use it's say on whether the randomness is strong - $this->strong = !!$openssl_strong; - } - wfProfileOut( __METHOD__ . '-openssl' ); - } - } - - // Only read from urandom if we can control the buffer size or were passed forceStrong - if ( strlen( $buffer ) < $bytes && ( function_exists( 'stream_set_read_buffer' ) || $forceStrong ) ) { - wfProfileIn( __METHOD__ . '-fopen-urandom' ); - $rem = $bytes - strlen( $buffer ); - if ( !function_exists( 'stream_set_read_buffer' ) && $forceStrong ) { - wfDebug( __METHOD__ . ": Was forced to read from /dev/urandom without control over the buffer size.\n" ); - } - // /dev/urandom is generally considered the best possible commonly - // available random source, and is available on most *nix systems. - wfSuppressWarnings(); - $urandom = fopen( "/dev/urandom", "rb" ); - wfRestoreWarnings(); - - // Attempt to read all our random data from urandom - // php's fread always does buffered reads based on the stream's chunk_size - // so in reality it will usually read more than the amount of data we're - // asked for and not storing that risks depleting the system's random pool. - // If stream_set_read_buffer is available set the chunk_size to the amount - // of data we need. Otherwise read 8k, php's default chunk_size. - if ( $urandom ) { - // php's default chunk_size is 8k - $chunk_size = 1024 * 8; - if ( function_exists( 'stream_set_read_buffer' ) ) { - // If possible set the chunk_size to the amount of data we need - stream_set_read_buffer( $urandom, $rem ); - $chunk_size = $rem; - } - $random_bytes = fread( $urandom, max( $chunk_size, $rem ) ); - $buffer .= $random_bytes; - fclose( $urandom ); - wfDebug( __METHOD__ . ": /dev/urandom generated " . strlen( $random_bytes ) . " bytes of randomness.\n" ); - if ( strlen( $buffer ) >= $bytes ) { - // urandom is always strong, set to true if all our data was generated using it - $this->strong = true; - } - } else { - wfDebug( __METHOD__ . ": /dev/urandom could not be opened.\n" ); - } - wfProfileOut( __METHOD__ . '-fopen-urandom' ); - } - - // If we cannot use or generate enough data from a secure source - // use this loop to generate a good set of pseudo random data. - // This works by initializing a random state using a pile of unstable data - // and continually shoving it through a hash along with a variable salt. - // We hash the random state with more salt to avoid the state from leaking - // out and being used to predict the /randomness/ that follows. - if ( strlen( $buffer ) < $bytes ) { - wfDebug( __METHOD__ . ": Falling back to using a pseudo random state to generate randomness.\n" ); - } - while ( strlen( $buffer ) < $bytes ) { - wfProfileIn( __METHOD__ . '-fallback' ); - $buffer .= $this->hmac( $this->randomState(), mt_rand() ); - // This code is never really cryptographically strong, if we use it - // at all, then set strong to false. - $this->strong = false; - wfProfileOut( __METHOD__ . '-fallback' ); - } - - // Once the buffer has been filled up with enough random data to fulfill - // the request shift off enough data to handle the request and leave the - // unused portion left inside the buffer for the next request for random data - $generated = substr( $buffer, 0, $bytes ); - $buffer = substr( $buffer, $bytes ); - - wfDebug( __METHOD__ . ": " . strlen( $buffer ) . " bytes of randomness leftover in the buffer.\n" ); - - wfProfileOut( __METHOD__ ); - return $generated; - } - - /** - * @see self::generateHex() - */ - public function realGenerateHex( $chars, $forceStrong = false ) { - // hex strings are 2x the length of raw binary so we divide the length in half - // odd numbers will result in a .5 that leads the generate() being 1 character - // short, so we use ceil() to ensure that we always have enough bytes - $bytes = ceil( $chars / 2 ); - // Generate the data and then convert it to a hex string - $hex = bin2hex( $this->generate( $bytes, $forceStrong ) ); - // A bit of paranoia here, the caller asked for a specific length of string - // here, and it's possible (eg when given an odd number) that we may actually - // have at least 1 char more than they asked for. Just in case they made this - // call intending to insert it into a database that does truncation we don't - // want to give them too much and end up with their database and their live - // code having two different values because part of what we gave them is truncated - // hence, we strip out any run of characters longer than what we were asked for. - return substr( $hex, 0, $chars ); - } - - /** Publicly exposed static methods **/ - - /** - * Return a singleton instance of MWCryptRand - * @return MWCryptRand - */ - protected static function singleton() { - if ( is_null( self::$singleton ) ) { - self::$singleton = new self; - } - return self::$singleton; - } - - /** - * Return a boolean indicating whether or not the source used for cryptographic - * random bytes generation in the previously run generate* call - * was cryptographically strong. - * - * @return bool Returns true if the source was strong, false if not. - */ - public static function wasStrong() { - return self::singleton()->realWasStrong(); - } - - /** - * Generate a run of (ideally) cryptographically random data and return - * it in raw binary form. - * You can use MWCryptRand::wasStrong() if you wish to know if the source used - * was cryptographically strong. - * - * @param int $bytes the number of bytes of random data to generate - * @param bool $forceStrong Pass true if you want generate to prefer cryptographically - * strong sources of entropy even if reading from them may steal - * more entropy from the system than optimal. - * @return String Raw binary random data - */ - public static function generate( $bytes, $forceStrong = false ) { - return self::singleton()->realGenerate( $bytes, $forceStrong ); - } - - /** - * Generate a run of (ideally) cryptographically random data and return - * it in hexadecimal string format. - * You can use MWCryptRand::wasStrong() if you wish to know if the source used - * was cryptographically strong. - * - * @param int $chars the number of hex chars of random data to generate - * @param bool $forceStrong Pass true if you want generate to prefer cryptographically - * strong sources of entropy even if reading from them may steal - * more entropy from the system than optimal. - * @return String Hexadecimal random data - */ - public static function generateHex( $chars, $forceStrong = false ) { - return self::singleton()->realGenerateHex( $chars, $forceStrong ); - } - -} |