* 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
*/
+use Psr\Log\LoggerInterface;
-class MWCryptRand {
-
+class CryptRand {
/**
* Minimum number of iterations we want to make in our drift calculations.
*/
const MSEC_PER_BYTE = 0.5;
/**
- * Singleton instance for public use
+ * A boolean indicating whether the previous random generation was done using
+ * cryptographically strong random number generator or not.
*/
- protected static $singleton = null;
+ protected $strong = null;
/**
- * The hash algorithm being used
+ * List of functions to call to generate some random state
+ *
+ * @var callable[]
*/
- protected $algo = null;
+ protected $randomFuncs = [];
/**
- * The number of bytes outputted by the hash algorithm
+ * List of files to generate some random state from
+ *
+ * @var string[]
*/
- protected $hashLength = null;
+ protected $randomFiles = [];
/**
- * A boolean indicating whether the previous random generation was done using
- * cryptographically strong random number generator or not.
+ * @var LoggerInterface
*/
- protected $strong = null;
+ protected $logger;
+
+ public function __construct( array $randomFuncs, array $randomFiles, LoggerInterface $logger ) {
+ $this->randomFuncs = $randomFuncs;
+ $this->randomFiles = $randomFiles;
+ $this->logger = $logger;
+ }
/**
* 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 also vary slightly across different machines
$state = serialize( $_SERVER );
- // To try and 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 ourself
+ $files = $this->randomFiles;
+
+ // We know this file is here so grab some info about ourselves
$files[] = __FILE__;
- // The config file is likely the most often edited file we know should be around
- // so if the constant with it's location is defined include it's stat info into the state
- if ( defined( 'MW_CONFIG_FILE' ) ) {
- $files[] = MW_CONFIG_FILE;
- }
+
+ // We must also have a parent folder, and with the usual file structure, a grandparent
+ $files[] = __DIR__;
+ $files[] = dirname( __DIR__ );
+
foreach ( $files as $file ) {
- wfSuppressWarnings();
+ MediaWiki\suppressWarnings();
$stat = stat( $file );
- wfRestoreWarnings();
+ MediaWiki\restoreWarnings();
if ( $stat ) {
// stat() duplicates data into numeric and string keys so kill off all the numeric ones
foreach ( $stat as $k => $v ) {
}
}
// The absolute filename itself will differ from install to install so don't leave it out
- $state .= realpath( $file );
+ $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
$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;
+ foreach ( $this->randomFuncs as $randomFunc ) {
+ $state .= call_user_func( $randomFunc );
}
return $state;
/**
* Randomly hash data while mixing in clock drift data for randomness
*
- * @param $data string The data to randomly hash.
- * @return String The hashed bytes
+ * @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)
+ // 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();
+ $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 $minIerations number of iterations
+ // Iterate for $duration seconds or at least $minIterations number of iterations
$iterations = 0;
$startTime = microtime( true );
$currentTime = $startTime;
$iterations++;
}
$timeTaken = $currentTime - $startTime;
- $data = $this->hash( $data );
+ $data = MWCryptHash::hash( $data );
- wfDebug( __METHOD__ . ": Clock drift calculation " .
+ $this->logger->debug( "Clock drift calculation " .
"(time-taken=" . ( $timeTaken * 1000 ) . "ms, " .
"iterations=$iterations, " .
- "time-per-iteration=" . ( $timeTaken / $iterations * 1e6 ) . "us)\n" );
+ "time-per-iteration=" . ( $timeTaken / $iterations * 1e6 ) . "us)" );
+
return $data;
}
// 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() );
+ $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;
- }
-
- /**
- * 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 );
+ return $state;
}
/**
- * Generate an acceptably unstable one-way-hmac of some text
- * making use of the best hash algorithm that we have available.
+ * Return a boolean indicating whether or not the source used for cryptographic
+ * random bytes generation in the previously run generate* call
+ * was cryptographically strong.
*
- * @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()
+ * @return bool Returns true if the source was strong, false if not.
*/
- public function realWasStrong() {
+ public function wasStrong() {
if ( is_null( $this->strong ) ) {
- throw new MWException( __METHOD__ . ' called before generation of random data' );
+ throw new RuntimeException( __METHOD__ . ' called before generation of random data' );
}
+
return $this->strong;
}
/**
- * @see self::generate()
+ * Generate a run of (ideally) cryptographically random data and return
+ * it in raw binary form.
+ * You can use CryptRand::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 function realGenerate( $bytes, $forceStrong = false ) {
- wfProfileIn( __METHOD__ );
-
- wfDebug( __METHOD__ . ": Generating cryptographic random bytes for " . wfGetAllCallers( 5 ) . "\n" );
-
+ public function generate( $bytes, $forceStrong = false ) {
$bytes = floor( $bytes );
static $buffer = '';
if ( is_null( $this->strong ) ) {
$this->strong = true;
}
+ if ( strlen( $buffer ) < $bytes ) {
+ // If available make use of PHP 7's random_bytes
+ // On Linux, getrandom syscall will be used if available.
+ // On Windows CryptGenRandom will always be used
+ // On other platforms, /dev/urandom will be used.
+ // Avoids polyfills from before php 7.0
+ // All error situations will throw Exceptions and or Errors
+ if ( PHP_VERSION_ID >= 70000
+ || ( defined( 'HHVM_VERSION_ID' ) && HHVM_VERSION_ID >= 31101 )
+ ) {
+ $rem = $bytes - strlen( $buffer );
+ $buffer .= random_bytes( $rem );
+ }
+ if ( strlen( $buffer ) >= $bytes ) {
+ $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 openbasdir restrictions so it's preferable to reading directly
+ // 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" );
+ $this->logger->debug( "mcrypt_create_iv returned false." );
} else {
$buffer .= $iv;
- wfDebug( __METHOD__ . ": mcrypt_create_iv generated " . strlen( $iv ) . " bytes of randomness.\n" );
+ $this->logger->debug( "mcrypt_create_iv generated " . strlen( $iv ) .
+ " bytes of randomness." );
}
- wfProfileOut( __METHOD__ . '-mcrypt' );
}
}
if ( strlen( $buffer ) < $bytes ) {
- // If available make use of openssl's random_pesudo_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
- if ( function_exists( 'openssl_random_pseudo_bytes' )
- && ( !wfIsWindows() || version_compare( PHP_VERSION, '5.3.4', '>=' ) )
- ) {
- wfProfileIn( __METHOD__ . '-openssl' );
+ 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" );
+ $this->logger->debug( "openssl_random_pseudo_bytes returned false." );
} else {
$buffer .= $openssl_bytes;
- wfDebug( __METHOD__ . ": openssl_random_pseudo_bytes generated " . strlen( $openssl_bytes ) . " bytes of " . ( $openssl_strong ? "strong" : "weak" ) . " randomness.\n" );
+ $this->logger->debug( "openssl_random_pseudo_bytes generated " .
+ strlen( $openssl_bytes ) . " bytes of " .
+ ( $openssl_strong ? "strong" : "weak" ) . " randomness." );
}
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' );
+ 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" );
+ $this->logger->debug( "Was forced to read from /dev/urandom " .
+ "without control over the buffer size." );
}
// /dev/urandom is generally considered the best possible commonly
// available random source, and is available on most *nix systems.
- wfSuppressWarnings();
+ MediaWiki\suppressWarnings();
$urandom = fopen( "/dev/urandom", "rb" );
- wfRestoreWarnings();
+ 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
$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" );
+ $this->logger->debug( "/dev/urandom generated " . strlen( $random_bytes ) .
+ " bytes of randomness." );
+
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" );
+ $this->logger->debug( "/dev/urandom could not be opened." );
}
- wfProfileOut( __METHOD__ . '-fopen-urandom' );
}
// If we cannot use or generate enough data from a secure source
// 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" );
+ $this->logger->debug( __METHOD__ .
+ ": Falling back to using a pseudo random state to generate randomness." );
}
while ( strlen( $buffer ) < $bytes ) {
- wfProfileIn( __METHOD__ . '-fallback' );
- $buffer .= $this->hmac( $this->randomState(), mt_rand() );
+ $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;
- wfProfileOut( __METHOD__ . '-fallback' );
}
// Once the buffer has been filled up with enough random data to fulfill
$generated = substr( $buffer, 0, $bytes );
$buffer = substr( $buffer, $bytes );
- wfDebug( __METHOD__ . ": " . strlen( $buffer ) . " bytes of randomness leftover in the buffer.\n" );
+ $this->logger->debug( strlen( $buffer ) .
+ " bytes of randomness leftover in the buffer." );
- wfProfileOut( __METHOD__ );
return $generated;
}
/**
- * @see self::generateHex()
+ * Generate a run of (ideally) cryptographically random data and return
+ * it in hexadecimal string format.
+ * You can use CryptRand::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 function realGenerateHex( $chars, $forceStrong = false ) {
+ public function generateHex( $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
// 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 $bytes int the number of bytes of random data to generate
- * @param $forceStrong bool 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 $chars int the number of hex chars of random data to generate
- * @param $forceStrong bool 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 );
- }
-
}
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