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<?php |
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|
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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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* http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06 |
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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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/** |
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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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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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); |
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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|null $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 $allowed_algs List of supported verification algorithms |
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* Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256' |
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* |
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* @return object The JWT's payload as a PHP object |
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* |
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* @throws DomainException Algorithm was not provided |
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* @throws UnexpectedValueException Provided JWT was invalid |
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* @throws SignatureInvalidException Provided JWT was invalid because the signature verification failed |
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* @throws BeforeValidException Provided JWT is trying to be used before it's eligible as defined by 'nbf' |
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* @throws BeforeValidException Provided JWT is trying to be used before it's been created as defined by 'iat' |
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* @throws ExpiredException Provided JWT has since expired, as defined by the 'exp' claim |
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* |
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* @uses jsonDecode |
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* @uses urlsafeB64Decode |
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*/ |
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public static function decode($jwt, $key, $allowed_algs = array()) |
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{ |
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if (empty($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 = JWT::jsonDecode(JWT::urlsafeB64Decode($headb64)))) { |
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throw new UnexpectedValueException('Invalid header encoding'); |
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} |
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if (null === $payload = JWT::jsonDecode(JWT::urlsafeB64Decode($bodyb64))) { |
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throw new UnexpectedValueException('Invalid claims encoding'); |
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} |
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$sig = JWT::urlsafeB64Decode($cryptob64); |
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|
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if (empty($header->alg)) { |
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throw new DomainException('Empty algorithm'); |
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} |
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if (empty(self::$supported_algs[$header->alg])) { |
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throw new DomainException('Algorithm not supported'); |
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} |
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if (!is_array($allowed_algs) || !in_array($header->alg, $allowed_algs)) { |
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throw new DomainException('Algorithm not allowed'); |
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} |
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if (is_array($key) || $key instanceof \ArrayAccess) { |
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if (isset($header->kid)) { |
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$key = $key[$header->kid]; |
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} else { |
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throw new DomainException('"kid" empty, unable to lookup correct key'); |
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} |
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} |
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|
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// Check the signature |
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if (!JWT::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) { |
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throw new SignatureInvalidException('Signature verification failed'); |
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} |
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|
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// Check if the nbf if it is defined. This is the time that the |
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// token can actually be used. If it's not yet that time, abort. |
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if (isset($payload->nbf) && $payload->nbf > (time() + self::$leeway)) { |
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throw new BeforeValidException( |
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'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->nbf) |
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); |
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} |
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|
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// Check that this token has been created before 'now'. This prevents |
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// using tokens that have been created for later use (and haven't |
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// correctly used the nbf claim). |
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if (isset($payload->iat) && $payload->iat > (time() + self::$leeway)) { |
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throw new BeforeValidException( |
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'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->iat) |
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); |
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} |
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|
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// Check if this token has expired. |
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if (isset($payload->exp) && (time() - self::$leeway) >= $payload->exp) { |
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throw new ExpiredException('Expired token'); |
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} |
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|
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return $payload; |
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} |
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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 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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$segments[] = JWT::urlsafeB64Encode(JWT::jsonEncode($header)); |
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$segments[] = JWT::urlsafeB64Encode(JWT::jsonEncode($payload)); |
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$signing_input = implode('.', $segments); |
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|
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$signature = JWT::sign($signing_input, $key, $alg); |
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$segments[] = JWT::urlsafeB64Encode($signature); |
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|
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return implode('.', $segments); |
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} |
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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, $alg = 'HS256') |
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{ |
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if (empty(self::$supported_algs[$alg])) { |
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throw new DomainException('Algorithm not supported'); |
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} |
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list($function, $algorithm) = self::$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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/** |
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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, $alg) |
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{ |
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if (empty(self::$supported_algs[$alg])) { |
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throw new DomainException('Algorithm not supported'); |
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} |
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|
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list($function, $algorithm) = self::$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) { |
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throw new DomainException("OpenSSL unable to verify data: " . openssl_error_string()); |
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} else { |
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return $signature; |
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} |
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case 'hash_hmac': |
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default: |
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$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(self::safeStrlen($signature), self::safeStrlen($hash)); |
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|
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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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$status |= (self::safeStrlen($signature) ^ self::safeStrlen($hash)); |
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|
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return ($status === 0); |
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} |
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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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|
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if (function_exists('json_last_error') && $errno = json_last_error()) { |
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JWT::handleJsonError($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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/** |
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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') && $errno = json_last_error()) { |
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JWT::handleJsonError($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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/** |
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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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/** |
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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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/** |
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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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$messages = array( |
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JSON_ERROR_DEPTH => 'Maximum stack depth exceeded', |
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JSON_ERROR_CTRL_CHAR => 'Unexpected control character found', |
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JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON' |
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); |
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throw new DomainException( |
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isset($messages[$errno]) |
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? $messages[$errno] |
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: 'Unknown JSON error: ' . $errno |
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); |
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} |
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|
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/** |
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* Get the number of bytes in cryptographic strings. |
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* |
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* @param string |
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* |
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* @return int |
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*/ |
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private static function safeStrlen($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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|
