381 lines
14 KiB
PHP
381 lines
14 KiB
PHP
<?php
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/*namespace Firebase\JWT;
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use \DomainException;
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use \InvalidArgumentException;
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use \UnexpectedValueException;
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use \DateTime;
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*/
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/**
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* JSON Web Token implementation, based on this spec:
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* https://tools.ietf.org/html/rfc7519
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*
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* PHP version 5
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*
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* @category Authentication
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* @package Authentication_JWT
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* @author Neuman Vong <neuman@twilio.com>
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* @author Anant Narayanan <anant@php.net>
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* @license http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
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* @link https://github.com/firebase/php-jwt
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*/
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class JWT
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{
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/**
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* When checking nbf, iat or expiration times,
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* we want to provide some extra leeway time to
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* account for clock skew.
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*/
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public static $leeway = 0;
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/**
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* Allow the current timestamp to be specified.
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* Useful for fixing a value within unit testing.
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*
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* Will default to PHP time() value if null.
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*/
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public static $timestamp = null;
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public static $supported_algs = array(
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'HS256' => array('hash_hmac', 'SHA256'),
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'HS512' => array('hash_hmac', 'SHA512'),
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'HS384' => array('hash_hmac', 'SHA384'),
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'RS256' => array('openssl', 'SHA256'),
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'RS384' => array('openssl', 'SHA384'),
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'RS512' => array('openssl', 'SHA512'),
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);
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/**
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* Decodes a JWT string into a PHP object.
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*
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* @param string $jwt The JWT
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* @param string|array $key The key, or map of keys.
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* If the algorithm used is asymmetric, this is the public key
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* @param array $allowed_algs List of supported verification algorithms
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* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
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*
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* @return object The JWT's payload as a PHP object
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*
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* @throws UnexpectedValueException Provided JWT was invalid
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* @throws SignatureInvalidException Provided JWT was invalid because the signature verification failed
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* @throws BeforeValidException Provided JWT is trying to be used before it's eligible as defined by 'nbf'
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* @throws BeforeValidException Provided JWT is trying to be used before it's been created as defined by 'iat'
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* @throws ExpiredException Provided JWT has since expired, as defined by the 'exp' claim
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*
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* @uses jsonDecode
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* @uses urlsafeB64Decode
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*/
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public static function decode($jwt, $key, array $allowed_algs = array())
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{
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$timestamp = is_null(static::$timestamp) ? time() : static::$timestamp;
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if (empty($key)) {
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throw new InvalidArgumentException('Key may not be empty');
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}
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$tks = explode('.', $jwt);
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if (count($tks) != 3) {
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throw new UnexpectedValueException('Wrong number of segments');
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}
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list($headb64, $bodyb64, $cryptob64) = $tks;
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if (null === ($header = static::jsonDecode(static::urlsafeB64Decode($headb64)))) {
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throw new UnexpectedValueException('Invalid header encoding');
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}
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if (null === $payload = static::jsonDecode(static::urlsafeB64Decode($bodyb64))) {
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throw new UnexpectedValueException('Invalid claims encoding');
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}
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if (false === ($sig = static::urlsafeB64Decode($cryptob64))) {
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throw new UnexpectedValueException('Invalid signature encoding');
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}
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if (empty($header->alg)) {
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throw new UnexpectedValueException('Empty algorithm');
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}
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if (empty(static::$supported_algs[$header->alg])) {
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throw new UnexpectedValueException('Algorithm not supported');
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}
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if (!in_array($header->alg, $allowed_algs)) {
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throw new UnexpectedValueException('Algorithm not allowed');
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}
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if (is_array($key) || $key instanceof \ArrayAccess) {
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if (isset($header->kid)) {
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if (!isset($key[$header->kid])) {
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throw new UnexpectedValueException('"kid" invalid, unable to lookup correct key');
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}
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$key = $key[$header->kid];
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} else {
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throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
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}
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}
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// Check the signature
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if (!static::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) {
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throw new SignatureInvalidException('Signature verification failed');
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}
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// Check if the nbf if it is defined. This is the time that the
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// token can actually be used. If it's not yet that time, abort.
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if (isset($payload->nbf) && $payload->nbf > ($timestamp + static::$leeway)) {
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throw new BeforeValidException(
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'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->nbf)
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);
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}
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// Check that this token has been created before 'now'. This prevents
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// using tokens that have been created for later use (and haven't
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// correctly used the nbf claim).
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if (isset($payload->iat) && $payload->iat > ($timestamp + static::$leeway)) {
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throw new BeforeValidException(
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'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->iat)
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);
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}
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// Check if this token has expired.
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if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
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throw new ExpiredException('Expired token');
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}
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return $payload;
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}
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/**
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* Converts and signs a PHP object or array into a JWT string.
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*
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* @param object|array $payload PHP object or array
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* @param string $key The secret key.
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* If the algorithm used is asymmetric, this is the private key
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* @param string $alg The signing algorithm.
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* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
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* @param mixed $keyId
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* @param array $head An array with header elements to attach
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*
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* @return string A signed JWT
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*
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* @uses jsonEncode
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* @uses urlsafeB64Encode
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*/
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public static function encode($payload, $key, $alg = 'HS256', $keyId = null, $head = null)
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{
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$header = array('typ' => 'JWT', 'alg' => $alg);
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if ($keyId !== null) {
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$header['kid'] = $keyId;
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}
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if ( isset($head) && is_array($head) ) {
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$header = array_merge($head, $header);
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}
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$segments = array();
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$segments[] = static::urlsafeB64Encode(static::jsonEncode($header));
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$segments[] = static::urlsafeB64Encode(static::jsonEncode($payload));
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$signing_input = implode('.', $segments);
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$signature = static::sign($signing_input, $key, $alg);
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$segments[] = static::urlsafeB64Encode($signature);
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return implode('.', $segments);
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}
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/**
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* Sign a string with a given key and algorithm.
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*
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* @param string $msg The message to sign
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* @param string|resource $key The secret key
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* @param string $alg The signing algorithm.
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* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
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*
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* @return string An encrypted message
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*
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* @throws DomainException Unsupported algorithm was specified
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*/
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public static function sign($msg, $key, $alg = 'HS256')
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{
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if (empty(static::$supported_algs[$alg])) {
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throw new DomainException('Algorithm not supported');
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}
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list($function, $algorithm) = static::$supported_algs[$alg];
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switch($function) {
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case 'hash_hmac':
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return hash_hmac($algorithm, $msg, $key, true);
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case 'openssl':
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$signature = '';
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$success = openssl_sign($msg, $signature, $key, $algorithm);
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if (!$success) {
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throw new DomainException("OpenSSL unable to sign data");
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} else {
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return $signature;
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}
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}
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}
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/**
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* Verify a signature with the message, key and method. Not all methods
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* are symmetric, so we must have a separate verify and sign method.
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*
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* @param string $msg The original message (header and body)
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* @param string $signature The original signature
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* @param string|resource $key For HS*, a string key works. for RS*, must be a resource of an openssl public key
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* @param string $alg The algorithm
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*
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* @return bool
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*
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* @throws DomainException Invalid Algorithm or OpenSSL failure
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*/
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private static function verify($msg, $signature, $key, $alg)
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{
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if (empty(static::$supported_algs[$alg])) {
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throw new DomainException('Algorithm not supported');
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}
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list($function, $algorithm) = static::$supported_algs[$alg];
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switch($function) {
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case 'openssl':
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$success = openssl_verify($msg, $signature, $key, $algorithm);
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if ($success === 1) {
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return true;
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} elseif ($success === 0) {
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return false;
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}
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// returns 1 on success, 0 on failure, -1 on error.
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throw new DomainException(
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'OpenSSL error: ' . openssl_error_string()
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);
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case 'hash_hmac':
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default:
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$hash = hash_hmac($algorithm, $msg, $key, true);
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if (function_exists('hash_equals')) {
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return hash_equals($signature, $hash);
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}
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$len = min(static::safeStrlen($signature), static::safeStrlen($hash));
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$status = 0;
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for ($i = 0; $i < $len; $i++) {
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$status |= (ord($signature[$i]) ^ ord($hash[$i]));
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}
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$status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));
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return ($status === 0);
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}
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}
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/**
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* Decode a JSON string into a PHP object.
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*
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* @param string $input JSON string
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*
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* @return object Object representation of JSON string
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*
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* @throws DomainException Provided string was invalid JSON
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*/
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public static function jsonDecode($input)
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{
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if (version_compare(PHP_VERSION, '5.4.0', '>=') && !(defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
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/** In PHP >=5.4.0, json_decode() accepts an options parameter, that allows you
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* to specify that large ints (like Steam Transaction IDs) should be treated as
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* strings, rather than the PHP default behaviour of converting them to floats.
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*/
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$obj = json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
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} else {
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/** Not all servers will support that, however, so for older versions we must
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* manually detect large ints in the JSON string and quote them (thus converting
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*them to strings) before decoding, hence the preg_replace() call.
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*/
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$max_int_length = strlen((string) PHP_INT_MAX) - 1;
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$json_without_bigints = preg_replace('/:\s*(-?\d{'.$max_int_length.',})/', ': "$1"', $input);
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$obj = json_decode($json_without_bigints);
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}
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if (function_exists('json_last_error') && $errno = json_last_error()) {
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static::handleJsonError($errno);
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} elseif ($obj === null && $input !== 'null') {
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throw new DomainException('Null result with non-null input');
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}
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return $obj;
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}
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/**
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* Encode a PHP object into a JSON string.
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*
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* @param object|array $input A PHP object or array
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*
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* @return string JSON representation of the PHP object or array
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*
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* @throws DomainException Provided object could not be encoded to valid JSON
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*/
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public static function jsonEncode($input)
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{
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$json = json_encode($input);
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if (function_exists('json_last_error') && $errno = json_last_error()) {
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static::handleJsonError($errno);
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} elseif ($json === 'null' && $input !== null) {
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throw new DomainException('Null result with non-null input');
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}
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return $json;
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}
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/**
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* Decode a string with URL-safe Base64.
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*
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* @param string $input A Base64 encoded string
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*
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* @return string A decoded string
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*/
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public static function urlsafeB64Decode($input)
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{
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$remainder = strlen($input) % 4;
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if ($remainder) {
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$padlen = 4 - $remainder;
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$input .= str_repeat('=', $padlen);
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}
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return base64_decode(strtr($input, '-_', '+/'));
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}
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/**
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* Encode a string with URL-safe Base64.
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*
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* @param string $input The string you want encoded
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*
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* @return string The base64 encode of what you passed in
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*/
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public static function urlsafeB64Encode($input)
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{
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return str_replace('=', '', strtr(base64_encode($input), '+/', '-_'));
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}
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/**
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* Helper method to create a JSON error.
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*
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* @param int $errno An error number from json_last_error()
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*
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* @return void
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*/
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private static function handleJsonError($errno)
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{
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$messages = array(
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JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
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JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
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JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
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JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
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JSON_ERROR_UTF8 => 'Malformed UTF-8 characters' //PHP >= 5.3.3
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);
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throw new DomainException(
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isset($messages[$errno])
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? $messages[$errno]
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: 'Unknown JSON error: ' . $errno
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);
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}
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/**
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* Get the number of bytes in cryptographic strings.
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*
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* @param string
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*
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* @return int
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*/
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private static function safeStrlen($str)
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{
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if (function_exists('mb_strlen')) {
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return mb_strlen($str, '8bit');
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}
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return strlen($str);
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}
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}
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