From 5bd6de67e38aef2ac5aba4861537ca0a53cfa7c3 Mon Sep 17 00:00:00 2001 From: Kunal Mehta Date: Sun, 2 Oct 2016 00:04:17 -0700 Subject: [PATCH] Move most of MWCryptRand into libs Dependency-inject the MW-specific parts of MWCryptRand via MediaWikiServices into a generic CryptRand class that is in libs/. Note that this removes the wfGetAllCallers() debug logging from generate(). Change-Id: I9742735c266ee69fb247199d3c553cd2ad2a3987 --- autoload.php | 1 + includes/MediaWikiServices.php | 9 + includes/ServiceWiring.php | 26 ++ includes/libs/CryptRand.php | 389 ++++++++++++++++++ includes/utils/MWCryptRand.php | 357 +--------------- .../includes/MediaWikiServicesTest.php | 1 + 6 files changed, 433 insertions(+), 350 deletions(-) create mode 100644 includes/libs/CryptRand.php diff --git a/autoload.php b/autoload.php index 5e81e833c9..cf491cb0a9 100644 --- a/autoload.php +++ b/autoload.php @@ -295,6 +295,7 @@ $wgAutoloadLocalClasses = [ 'CreateAndPromote' => __DIR__ . '/maintenance/createAndPromote.php', 'CreateFileOp' => __DIR__ . '/includes/libs/filebackend/fileop/CreateFileOp.php', 'CreditsAction' => __DIR__ . '/includes/actions/CreditsAction.php', + 'CryptRand' => __DIR__ . '/includes/libs/CryptRand.php', 'CssContent' => __DIR__ . '/includes/content/CssContent.php', 'CssContentHandler' => __DIR__ . '/includes/content/CssContentHandler.php', 'CsvStatsOutput' => __DIR__ . '/maintenance/language/StatOutputs.php', diff --git a/includes/MediaWikiServices.php b/includes/MediaWikiServices.php index b16044e12d..0f56797d49 100644 --- a/includes/MediaWikiServices.php +++ b/includes/MediaWikiServices.php @@ -3,6 +3,7 @@ namespace MediaWiki; use Config; use ConfigFactory; +use CryptRand; use EventRelayerGroup; use GenderCache; use GlobalVarConfig; @@ -522,6 +523,14 @@ class MediaWikiServices extends ServiceContainer { return $this->getService( 'WatchedItemQueryService' ); } + /** + * @since 1.28 + * @return CryptRand + */ + public function getCryptRand() { + return $this->getService( 'CryptRand' ); + } + /** * @since 1.28 * @return MediaHandlerFactory diff --git a/includes/ServiceWiring.php b/includes/ServiceWiring.php index 11ee616344..86f457867d 100644 --- a/includes/ServiceWiring.php +++ b/includes/ServiceWiring.php @@ -39,6 +39,7 @@ use MediaWiki\Interwiki\ClassicInterwikiLookup; use MediaWiki\Linker\LinkRendererFactory; +use MediaWiki\Logger\LoggerFactory; use MediaWiki\MediaWikiServices; return [ @@ -158,6 +159,31 @@ return [ return new WatchedItemQueryService( $services->getDBLoadBalancer() ); }, + 'CryptRand' => function( MediaWikiServices $services ) { + $secretKey = $services->getMainConfig()->get( 'SecretKey' ); + return new CryptRand( + [ + // To try vary the system information of the state a bit more + // by including the system's hostname into the state + 'wfHostname', + // It's mostly worthless but throw the wiki's id into the data + // for a little more variance + 'wfWikiID', + // If we have a secret key set then throw it into the state as well + function() use ( $secretKey ) { + return $secretKey ?: ''; + } + ], + // 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). + defined( 'MW_CONFIG_FILE' ) ? [ MW_CONFIG_FILE ] : [], + LoggerFactory::getInstance( 'CryptRand' ) + ); + }, + 'MediaHandlerFactory' => function( MediaWikiServices $services ) { return new MediaHandlerFactory( $services->getMainConfig()->get( 'MediaHandlers' ) diff --git a/includes/libs/CryptRand.php b/includes/libs/CryptRand.php new file mode 100644 index 0000000000..6d18c81ed6 --- /dev/null +++ b/includes/libs/CryptRand.php @@ -0,0 +1,389 @@ +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 vary a little with each page, and vary even more with separate users + // It'll also vary slightly across different machines + $state = serialize( $_SERVER ); + + // 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 = $this->randomFiles; + + // 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__ ); + + 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 ); + } + + foreach ( $this->randomFuncs as $randomFunc ) { + $state .= call_user_func( $randomFunc ); + } + + 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 ); + + $this->logger->debug( "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; + } + + /** + * 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 function wasStrong() { + if ( is_null( $this->strong ) ) { + throw new RuntimeException( __METHOD__ . ' called before generation of random data' ); + } + + return $this->strong; + } + + /** + * 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 generate( $bytes, $forceStrong = false ) { + + $this->logger->debug( "Generating cryptographic random bytes for\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 ) { + $this->logger->debug( "mcrypt_create_iv returned false.\n" ); + } else { + $buffer .= $iv; + $this->logger->debug( "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 ) { + $this->logger->debug( "openssl_random_pseudo_bytes returned false.\n" ); + } else { + $buffer .= $openssl_bytes; + $this->logger->debug( "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 ) { + $this->logger->debug( "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 ); + $this->logger->debug( "/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 { + $this->logger->debug( "/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 ) { + $this->logger->debug( __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 ); + + $this->logger->debug( strlen( $buffer ) . + " bytes of randomness leftover in the buffer.\n" ); + + return $generated; + } + + /** + * 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 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 + // 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 ); + } +} diff --git a/includes/utils/MWCryptRand.php b/includes/utils/MWCryptRand.php index dd3ea1b87e..581895807c 100644 --- a/includes/utils/MWCryptRand.php +++ b/includes/utils/MWCryptRand.php @@ -24,357 +24,14 @@ * @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(); } /** @@ -385,7 +42,7 @@ class MWCryptRand { * @return bool Returns true if the source was strong, false if not. */ public static function wasStrong() { - return self::singleton()->realWasStrong(); + return self::singleton()->wasStrong(); } /** @@ -401,7 +58,7 @@ class MWCryptRand { * @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 ); } /** @@ -417,6 +74,6 @@ class MWCryptRand { * @return string Hexadecimal random data */ public static function generateHex( $chars, $forceStrong = false ) { - return self::singleton()->realGenerateHex( $chars, $forceStrong ); + return self::singleton()->generateHex( $chars, $forceStrong ); } } diff --git a/tests/phpunit/includes/MediaWikiServicesTest.php b/tests/phpunit/includes/MediaWikiServicesTest.php index a05e39d974..ebe00ffb37 100644 --- a/tests/phpunit/includes/MediaWikiServicesTest.php +++ b/tests/phpunit/includes/MediaWikiServicesTest.php @@ -312,6 +312,7 @@ class MediaWikiServicesTest extends MediaWikiTestCase { 'DBLoadBalancer' => [ 'DBLoadBalancer', 'LoadBalancer' ], 'WatchedItemStore' => [ 'WatchedItemStore', WatchedItemStore::class ], 'WatchedItemQueryService' => [ 'WatchedItemQueryService', WatchedItemQueryService::class ], + 'CryptRand' => [ 'CryptRand', CryptRand::class ], 'MediaHandlerFactory' => [ 'MediaHandlerFactory', MediaHandlerFactory::class ], 'GenderCache' => [ 'GenderCache', GenderCache::class ], 'LinkCache' => [ 'LinkCache', LinkCache::class ], -- 2.20.1