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<?php |
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namespace dologin\lib; |
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|
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/** |
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* PHP Class for handling Google Authenticator 2-factor authentication. |
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* |
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* @author Michael Kliewe |
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* @copyright 2012 Michael Kliewe |
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* @license http://www.opensource.org/licenses/bsd-license.php BSD License |
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* |
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* @link http://www.phpgangsta.de/ |
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*/ |
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class Two_FA_Lib { |
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|
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protected $_codeLength = 6; |
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|
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/** |
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* Create new secret. |
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* 16 characters, randomly chosen from the allowed base32 characters. |
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* |
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* @param int $secretLength |
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* |
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* @return string |
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*/ |
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public function createSecret( $secretLength = 16 ) { |
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$validChars = $this->_getBase32LookupTable(); |
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|
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// Valid secret lengths are 80 to 640 bits |
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if ( $secretLength < 16 || $secretLength > 128 ) { |
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throw new \Exception( 'Bad secret length' ); |
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} |
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$secret = ''; |
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$rnd = false; |
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if ( function_exists( 'random_bytes' ) ) { |
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$rnd = random_bytes( $secretLength ); |
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} elseif ( function_exists( 'mcrypt_create_iv' ) ) { |
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$rnd = mcrypt_create_iv( $secretLength, MCRYPT_DEV_URANDOM ); |
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} elseif ( function_exists( 'openssl_random_pseudo_bytes' ) ) { |
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$rnd = openssl_random_pseudo_bytes( $secretLength, $cryptoStrong ); |
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if ( ! $cryptoStrong ) { |
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$rnd = false; |
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} |
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} |
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if ( $rnd !== false ) { |
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for ( $i = 0; $i < $secretLength; ++$i ) { |
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$secret .= $validChars[ ord( $rnd[ $i ] ) & 31 ]; |
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} |
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} else { |
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throw new \Exception( 'No source of secure random' ); |
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} |
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|
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return $secret; |
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} |
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|
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/** |
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* Calculate the code, with given secret and point in time. |
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* |
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* @param string $secret |
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* @param int|null $timeSlice |
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* |
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* @return string |
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*/ |
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public function getCode( $secret, $timeSlice = null ) { |
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if ( $timeSlice === null ) { |
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$timeSlice = floor( time() / 30 ); |
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} |
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|
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$secretkey = $this->_base32Decode( $secret ); |
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|
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// Pack time into binary string |
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$time = chr( 0 ) . chr( 0 ) . chr( 0 ) . chr( 0 ) . pack( 'N*', $timeSlice ); |
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// Hash it with users secret key |
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$hm = hash_hmac( 'SHA1', $time, $secretkey, true ); |
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// Use last nipple of result as index/offset |
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$offset = ord( substr( $hm, -1 ) ) & 0x0F; |
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// grab 4 bytes of the result |
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$hashpart = substr( $hm, $offset, 4 ); |
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|
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// Unpak binary value |
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$value = unpack( 'N', $hashpart ); |
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$value = $value[1]; |
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// Only 32 bits |
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$value = $value & 0x7FFFFFFF; |
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|
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$modulo = pow( 10, $this->_codeLength ); |
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|
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return str_pad( $value % $modulo, $this->_codeLength, '0', STR_PAD_LEFT ); |
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} |
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|
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/** |
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* Get QR-Code URL for image, from google charts. |
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* |
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* @param string $name |
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* @param string $secret |
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* @param string $title |
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* @param array $params |
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* |
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* @return string |
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*/ |
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public function getQRCodeGoogleUrl( $name, $secret, $title = null, $params = array() ) { |
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$width = ! empty( $params['width'] ) && (int) $params['width'] > 0 ? (int) $params['width'] : 200; |
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$height = ! empty( $params['height'] ) && (int) $params['height'] > 0 ? (int) $params['height'] : 200; |
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$level = ! empty( $params['level'] ) && array_search( $params['level'], array( 'L', 'M', 'Q', 'H' ) ) !== false ? $params['level'] : 'M'; |
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|
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$urlencoded = 'otpauth://totp/' . $name . '?secret=' . $secret; |
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if ( isset( $title ) ) { |
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$urlencoded .= '&issuer=' . rawurlencode( $title ); |
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} |
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|
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return $urlencoded; |
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} |
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|
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/** |
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* Check if the code is correct. This will accept codes starting from $discrepancy*30sec ago to $discrepancy*30sec from now. |
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* |
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* @param string $secret |
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* @param string $code |
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* @param int $discrepancy This is the allowed time drift in 30 second units (8 means 4 minutes before or after) |
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* @param int|null $currentTimeSlice time slice if we want use other that time() |
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* |
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* @return bool |
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*/ |
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public function verifyCode( $secret, $code, $discrepancy = 1, $currentTimeSlice = null ) { |
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return false !== $this->findValidTimeSlice( $secret, $code, $discrepancy, $currentTimeSlice ); |
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} |
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|
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/** |
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* Return the matched time slice so callers can block TOTP replay. |
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* |
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* @param string $secret |
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* @param string $code |
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* @param int $discrepancy |
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* @param int|null $currentTimeSlice |
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* |
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* @return int|false |
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*/ |
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public function findValidTimeSlice( $secret, $code, $discrepancy = 1, $currentTimeSlice = null ) { |
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if ( $currentTimeSlice === null ) { |
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$currentTimeSlice = (int) floor( time() / 30 ); |
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} |
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|
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if ( strlen( $code ) != 6 ) { |
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return false; |
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} |
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|
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for ( $i = -$discrepancy; $i <= $discrepancy; ++$i ) { |
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$matched_slice = (int) $currentTimeSlice + $i; |
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$calculatedCode = $this->getCode( $secret, $matched_slice ); |
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if ( $this->timingSafeEquals( $calculatedCode, $code ) ) { |
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return $matched_slice; |
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} |
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} |
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|
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return false; |
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} |
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|
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/** |
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* Set the code length, should be >=6. |
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* |
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* @param int $length |
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* |
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* @return PHPGangsta_GoogleAuthenticator |
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*/ |
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public function setCodeLength( $length ) { |
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$this->_codeLength = $length; |
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|
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return $this; |
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} |
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|
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/** |
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* Helper class to decode base32. |
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* |
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* @param $secret |
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* |
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* @return bool|string |
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*/ |
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protected function _base32Decode( $secret ) { |
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if ( empty( $secret ) ) { |
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return ''; |
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} |
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|
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$base32chars = $this->_getBase32LookupTable(); |
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$base32charsFlipped = array_flip( $base32chars ); |
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|
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$paddingCharCount = substr_count( $secret, $base32chars[32] ); |
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$allowedValues = array( 6, 4, 3, 1, 0 ); |
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if ( ! in_array( $paddingCharCount, $allowedValues ) ) { |
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return false; |
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} |
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for ( $i = 0; $i < 4; ++$i ) { |
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if ( $paddingCharCount == $allowedValues[ $i ] && |
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substr( $secret, -( $allowedValues[ $i ] ) ) != str_repeat( $base32chars[32], $allowedValues[ $i ] ) ) { |
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return false; |
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} |
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} |
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$secret = str_replace( '=', '', $secret ); |
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$secret = str_split( $secret ); |
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$binaryString = ''; |
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for ( $i = 0; $i < count( $secret ); $i = $i + 8 ) { |
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$x = ''; |
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if ( ! in_array( $secret[ $i ], $base32chars ) ) { |
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return false; |
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} |
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for ( $j = 0; $j < 8; ++$j ) { |
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$x .= str_pad( base_convert( @$base32charsFlipped[ @$secret[ $i + $j ] ], 10, 2 ), 5, '0', STR_PAD_LEFT ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged -- vendored PHPGangsta TOTP library. |
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} |
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$eightBits = str_split( $x, 8 ); |
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for ( $z = 0; $z < count( $eightBits ); ++$z ) { |
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$binaryString .= ( ( $y = chr( base_convert( $eightBits[ $z ], 2, 10 ) ) ) || ord( $y ) == 48 ) ? $y : ''; // phpcs:ignore WordPress.CodeAnalysis.AssignmentInTernaryCondition.FoundInTernaryCondition -- vendored library. |
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} |
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} |
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|
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return $binaryString; |
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} |
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|
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/** |
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* Get array with all 32 characters for decoding from/encoding to base32. |
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* |
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* @return array |
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*/ |
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protected function _getBase32LookupTable() { |
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return array( |
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'A', |
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'B', |
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'C', |
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'D', |
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'E', |
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'F', |
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'G', |
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'H', // 7 |
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'I', |
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'J', |
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'K', |
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'L', |
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'M', |
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'N', |
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'O', |
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'P', // 15 |
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'Q', |
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'R', |
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'S', |
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'T', |
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'U', |
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'V', |
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'W', |
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'X', // 23 |
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'Y', |
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'Z', |
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'2', |
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'3', |
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'4', |
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'5', |
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'6', |
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'7', // 31 |
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'=', // padding char |
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); |
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} |
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|
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/** |
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* A timing safe equals comparison |
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* more info here: http://blog.ircmaxell.com/2014/11/its-all-about-time.html. |
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* |
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* @param string $safeString The internal (safe) value to be checked |
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* @param string $userString The user submitted (unsafe) value |
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* |
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* @return bool True if the two strings are identical |
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*/ |
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private function timingSafeEquals( $safeString, $userString ) { |
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if ( function_exists( 'hash_equals' ) ) { |
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return hash_equals( $safeString, $userString ); |
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} |
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$safeLen = strlen( $safeString ); |
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$userLen = strlen( $userString ); |
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|
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if ( $userLen != $safeLen ) { |
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return false; |
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} |
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|
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$result = 0; |
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|
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for ( $i = 0; $i < $userLen; ++$i ) { |
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$result |= ( ord( $safeString[ $i ] ) ^ ord( $userString[ $i ] ) ); |
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} |
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|
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// They are only identical strings if $result is exactly 0... |
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return $result === 0; |
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} |
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} |
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|
