* @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;
-
- /**
- * 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
- * @return string
- */
- 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 = [];
-
- // 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 (e.g. the installer).
- if ( defined( 'MW_CONFIG_FILE' ) ) {
- $files[] = MW_CONFIG_FILE;
- }
-
- foreach ( $files as $file ) {
- MediaWiki\suppressWarnings();
- $stat = stat( $file );
- MediaWiki\restoreWarnings();
- 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
- $path = realpath( $file );
- if ( $path !== 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 set then throw it into the state as well
- global $wgSecretKey;
- if ( $wgSecretKey ) {
- $state .= $wgSecretKey;
- }
-
- 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 ) * MWCryptHash::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 = MWCryptHash::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 = MWCryptHash::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;
- }
-
- /**
- * @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 ) {
-
- 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' ) ) {
- $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" );
- }
- }
- }
-
- if ( strlen( $buffer ) < $bytes ) {
- if ( function_exists( 'openssl_random_pseudo_bytes' ) ) {
- $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;
- }
- }
- }
-
- // 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 )
- ) {
- $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.
- MediaWiki\suppressWarnings();
- $urandom = fopen( "/dev/urandom", "rb" );
- MediaWiki\restoreWarnings();
-
- // 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" );
- }
- }
-
- // 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 ) {
- $buffer .= MWCryptHash::hmac( $this->randomState(), strval( mt_rand() ) );
- // This code is never really cryptographically strong, if we use it
- // at all, then set strong to false.
- $this->strong = false;
- }
-
- // 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" );
-
- 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, $chars );
- }
-
- /** Publicly exposed static methods **/
+use MediaWiki\MediaWikiServices;
+class MWCryptRand {
/**
- * Return a singleton instance of MWCryptRand
- * @return MWCryptRand
+ * @return CryptRand
*/
protected static function singleton() {
- if ( is_null( self::$singleton ) ) {
- self::$singleton = new self;
- }
-
- return self::$singleton;
+ return MediaWikiServices::getInstance()->getCryptRand();
}
/**
* @return bool Returns true if the source was strong, false if not.
*/
public static function wasStrong() {
- return self::singleton()->realWasStrong();
+ return self::singleton()->wasStrong();
}
/**
* @return string Raw binary random data
*/
public static function generate( $bytes, $forceStrong = false ) {
- return self::singleton()->realGenerate( $bytes, $forceStrong );
+ return self::singleton()->generate( $bytes, $forceStrong );
}
/**
* @return string Hexadecimal random data
*/
public static function generateHex( $chars, $forceStrong = false ) {
- return self::singleton()->realGenerateHex( $chars, $forceStrong );
+ return self::singleton()->generateHex( $chars, $forceStrong );
}
}
dépôts / lhc / web / wiklou.git / blobdiff