--- /dev/null
+<?php
+
+namespace Firebase\JWT;
+use \DomainException;
+use \InvalidArgumentException;
+use \UnexpectedValueException;
+use \DateTime;
+
+/**
+ * JSON Web Token implementation, based on this spec:
+ * http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06
+ *
+ * PHP version 5
+ *
+ * @category Authentication
+ * @package Authentication_JWT
+ * @author Neuman Vong <neuman@twilio.com>
+ * @author Anant Narayanan <anant@php.net>
+ * @license http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
+ * @link https://github.com/firebase/php-jwt
+ */
+class JWT
+{
+
+ /**
+ * When checking nbf, iat or expiration times,
+ * we want to provide some extra leeway time to
+ * account for clock skew.
+ */
+ public static $leeway = 0;
+
+ /**
+ * Allow the current timestamp to be specified.
+ * Useful for fixing a value within unit testing.
+ *
+ * Will default to PHP time() value if null.
+ */
+ public static $timestamp = null;
+
+ public static $supported_algs = array(
+ 'HS256' => array('hash_hmac', 'SHA256'),
+ 'HS512' => array('hash_hmac', 'SHA512'),
+ 'HS384' => array('hash_hmac', 'SHA384'),
+ 'RS256' => array('openssl', 'SHA256'),
+ );
+
+ /**
+ * Decodes a JWT string into a PHP object.
+ *
+ * @param string $jwt The JWT
+ * @param string|array $key The key, or map of keys.
+ * If the algorithm used is asymmetric, this is the public key
+ * @param array $allowed_algs List of supported verification algorithms
+ * Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
+ *
+ * @return object The JWT's payload as a PHP object
+ *
+ * @throws UnexpectedValueException Provided JWT was invalid
+ * @throws SignatureInvalidException Provided JWT was invalid because the signature verification failed
+ * @throws BeforeValidException Provided JWT is trying to be used before it's eligible as defined by 'nbf'
+ * @throws BeforeValidException Provided JWT is trying to be used before it's been created as defined by 'iat'
+ * @throws ExpiredException Provided JWT has since expired, as defined by the 'exp' claim
+ *
+ * @uses jsonDecode
+ * @uses urlsafeB64Decode
+ */
+ public static function decode($jwt, $key, $allowed_algs = array())
+ {
+ $timestamp = is_null(static::$timestamp) ? time() : static::$timestamp;
+
+ if (empty($key)) {
+ throw new InvalidArgumentException('Key may not be empty');
+ }
+ if (!is_array($allowed_algs)) {
+ throw new InvalidArgumentException('Algorithm not allowed');
+ }
+ $tks = explode('.', $jwt);
+ if (count($tks) != 3) {
+ throw new UnexpectedValueException('Wrong number of segments');
+ }
+ list($headb64, $bodyb64, $cryptob64) = $tks;
+ if (null === ($header = static::jsonDecode(static::urlsafeB64Decode($headb64)))) {
+ throw new UnexpectedValueException('Invalid header encoding');
+ }
+ if (null === $payload = static::jsonDecode(static::urlsafeB64Decode($bodyb64))) {
+ throw new UnexpectedValueException('Invalid claims encoding');
+ }
+ $sig = static::urlsafeB64Decode($cryptob64);
+
+ if (empty($header->alg)) {
+ throw new UnexpectedValueException('Empty algorithm');
+ }
+ if (empty(static::$supported_algs[$header->alg])) {
+ throw new UnexpectedValueException('Algorithm not supported');
+ }
+ if (!in_array($header->alg, $allowed_algs)) {
+ throw new UnexpectedValueException('Algorithm not allowed');
+ }
+ if (is_array($key) || $key instanceof \ArrayAccess) {
+ if (isset($header->kid)) {
+ $key = $key[$header->kid];
+ } else {
+ throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
+ }
+ }
+
+ // Check the signature
+ if (!static::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) {
+ throw new SignatureInvalidException('Signature verification failed');
+ }
+
+ // Check if the nbf if it is defined. This is the time that the
+ // token can actually be used. If it's not yet that time, abort.
+ if (isset($payload->nbf) && $payload->nbf > ($timestamp + static::$leeway)) {
+ throw new BeforeValidException(
+ 'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->nbf)
+ );
+ }
+
+ // Check that this token has been created before 'now'. This prevents
+ // using tokens that have been created for later use (and haven't
+ // correctly used the nbf claim).
+ if (isset($payload->iat) && $payload->iat > ($timestamp + static::$leeway)) {
+ throw new BeforeValidException(
+ 'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->iat)
+ );
+ }
+
+ // Check if this token has expired.
+ if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
+ throw new ExpiredException('Expired token');
+ }
+
+ return $payload;
+ }
+
+ /**
+ * Converts and signs a PHP object or array into a JWT string.
+ *
+ * @param object|array $payload PHP object or array
+ * @param string $key The secret key.
+ * If the algorithm used is asymmetric, this is the private key
+ * @param string $alg The signing algorithm.
+ * Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
+ * @param mixed $keyId
+ * @param array $head An array with header elements to attach
+ *
+ * @return string A signed JWT
+ *
+ * @uses jsonEncode
+ * @uses urlsafeB64Encode
+ */
+ public static function encode($payload, $key, $alg = 'HS256', $keyId = null, $head = null)
+ {
+ $header = array('typ' => 'JWT', 'alg' => $alg);
+ if ($keyId !== null) {
+ $header['kid'] = $keyId;
+ }
+ if ( isset($head) && is_array($head) ) {
+ $header = array_merge($head, $header);
+ }
+ $segments = array();
+ $segments[] = static::urlsafeB64Encode(static::jsonEncode($header));
+ $segments[] = static::urlsafeB64Encode(static::jsonEncode($payload));
+ $signing_input = implode('.', $segments);
+
+ $signature = static::sign($signing_input, $key, $alg);
+ $segments[] = static::urlsafeB64Encode($signature);
+
+ return implode('.', $segments);
+ }
+
+ /**
+ * Sign a string with a given key and algorithm.
+ *
+ * @param string $msg The message to sign
+ * @param string|resource $key The secret key
+ * @param string $alg The signing algorithm.
+ * Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
+ *
+ * @return string An encrypted message
+ *
+ * @throws DomainException Unsupported algorithm was specified
+ */
+ public static function sign($msg, $key, $alg = 'HS256')
+ {
+ if (empty(static::$supported_algs[$alg])) {
+ throw new DomainException('Algorithm not supported');
+ }
+ list($function, $algorithm) = static::$supported_algs[$alg];
+ switch($function) {
+ case 'hash_hmac':
+ return hash_hmac($algorithm, $msg, $key, true);
+ case 'openssl':
+ $signature = '';
+ $success = openssl_sign($msg, $signature, $key, $algorithm);
+ if (!$success) {
+ throw new DomainException("OpenSSL unable to sign data");
+ } else {
+ return $signature;
+ }
+ }
+ }
+
+ /**
+ * Verify a signature with the message, key and method. Not all methods
+ * are symmetric, so we must have a separate verify and sign method.
+ *
+ * @param string $msg The original message (header and body)
+ * @param string $signature The original signature
+ * @param string|resource $key For HS*, a string key works. for RS*, must be a resource of an openssl public key
+ * @param string $alg The algorithm
+ *
+ * @return bool
+ *
+ * @throws DomainException Invalid Algorithm or OpenSSL failure
+ */
+ private static function verify($msg, $signature, $key, $alg)
+ {
+ if (empty(static::$supported_algs[$alg])) {
+ throw new DomainException('Algorithm not supported');
+ }
+
+ list($function, $algorithm) = static::$supported_algs[$alg];
+ switch($function) {
+ case 'openssl':
+ $success = openssl_verify($msg, $signature, $key, $algorithm);
+ if (!$success) {
+ throw new DomainException("OpenSSL unable to verify data: " . openssl_error_string());
+ } else {
+ return $signature;
+ }
+ case 'hash_hmac':
+ default:
+ $hash = hash_hmac($algorithm, $msg, $key, true);
+ if (function_exists('hash_equals')) {
+ return hash_equals($signature, $hash);
+ }
+ $len = min(static::safeStrlen($signature), static::safeStrlen($hash));
+
+ $status = 0;
+ for ($i = 0; $i < $len; $i++) {
+ $status |= (ord($signature[$i]) ^ ord($hash[$i]));
+ }
+ $status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));
+
+ return ($status === 0);
+ }
+ }
+
+ /**
+ * Decode a JSON string into a PHP object.
+ *
+ * @param string $input JSON string
+ *
+ * @return object Object representation of JSON string
+ *
+ * @throws DomainException Provided string was invalid JSON
+ */
+ public static function jsonDecode($input)
+ {
+ if (version_compare(PHP_VERSION, '5.4.0', '>=') && !(defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
+ /** In PHP >=5.4.0, json_decode() accepts an options parameter, that allows you
+ * to specify that large ints (like Steam Transaction IDs) should be treated as
+ * strings, rather than the PHP default behaviour of converting them to floats.
+ */
+ $obj = json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
+ } else {
+ /** Not all servers will support that, however, so for older versions we must
+ * manually detect large ints in the JSON string and quote them (thus converting
+ *them to strings) before decoding, hence the preg_replace() call.
+ */
+ $max_int_length = strlen((string) PHP_INT_MAX) - 1;
+ $json_without_bigints = preg_replace('/:\s*(-?\d{'.$max_int_length.',})/', ': "$1"', $input);
+ $obj = json_decode($json_without_bigints);
+ }
+
+ if (function_exists('json_last_error') && $errno = json_last_error()) {
+ static::handleJsonError($errno);
+ } elseif ($obj === null && $input !== 'null') {
+ throw new DomainException('Null result with non-null input');
+ }
+ return $obj;
+ }
+
+ /**
+ * Encode a PHP object into a JSON string.
+ *
+ * @param object|array $input A PHP object or array
+ *
+ * @return string JSON representation of the PHP object or array
+ *
+ * @throws DomainException Provided object could not be encoded to valid JSON
+ */
+ public static function jsonEncode($input)
+ {
+ $json = json_encode($input);
+ if (function_exists('json_last_error') && $errno = json_last_error()) {
+ static::handleJsonError($errno);
+ } elseif ($json === 'null' && $input !== null) {
+ throw new DomainException('Null result with non-null input');
+ }
+ return $json;
+ }
+
+ /**
+ * Decode a string with URL-safe Base64.
+ *
+ * @param string $input A Base64 encoded string
+ *
+ * @return string A decoded string
+ */
+ public static function urlsafeB64Decode($input)
+ {
+ $remainder = strlen($input) % 4;
+ if ($remainder) {
+ $padlen = 4 - $remainder;
+ $input .= str_repeat('=', $padlen);
+ }
+ return base64_decode(strtr($input, '-_', '+/'));
+ }
+
+ /**
+ * Encode a string with URL-safe Base64.
+ *
+ * @param string $input The string you want encoded
+ *
+ * @return string The base64 encode of what you passed in
+ */
+ public static function urlsafeB64Encode($input)
+ {
+ return str_replace('=', '', strtr(base64_encode($input), '+/', '-_'));
+ }
+
+ /**
+ * Helper method to create a JSON error.
+ *
+ * @param int $errno An error number from json_last_error()
+ *
+ * @return void
+ */
+ private static function handleJsonError($errno)
+ {
+ $messages = array(
+ JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
+ JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
+ JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON'
+ );
+ throw new DomainException(
+ isset($messages[$errno])
+ ? $messages[$errno]
+ : 'Unknown JSON error: ' . $errno
+ );
+ }
+
+ /**
+ * Get the number of bytes in cryptographic strings.
+ *
+ * @param string
+ *
+ * @return int
+ */
+ private static function safeStrlen($str)
+ {
+ if (function_exists('mb_strlen')) {
+ return mb_strlen($str, '8bit');
+ }
+ return strlen($str);
+ }
+}
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