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Differences Between: [Versions 311 and 400] [Versions 311 and 401] [Versions 311 and 402] [Versions 311 and 403]

   1  <?php
   2  
   3  namespace Firebase\JWT;
   4  
   5  use \DomainException;
   6  use \InvalidArgumentException;
   7  use \UnexpectedValueException;
   8  use \DateTime;
   9  
  10  /**
  11   * JSON Web Token implementation, based on this spec:
  12   * https://tools.ietf.org/html/rfc7519
  13   *
  14   * PHP version 5
  15   *
  16   * @category Authentication
  17   * @package  Authentication_JWT
  18   * @author   Neuman Vong <neuman@twilio.com>
  19   * @author   Anant Narayanan <anant@php.net>
  20   * @license  http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
  21   * @link     https://github.com/firebase/php-jwt
  22   */
  23  class JWT
  24  {
  25      const ASN1_INTEGER = 0x02;
  26      const ASN1_SEQUENCE = 0x10;
  27      const ASN1_BIT_STRING = 0x03;
  28  
  29      /**
  30       * When checking nbf, iat or expiration times,
  31       * we want to provide some extra leeway time to
  32       * account for clock skew.
  33       */
  34      public static $leeway = 180;
  35  
  36      /**
  37       * Allow the current timestamp to be specified.
  38       * Useful for fixing a value within unit testing.
  39       *
  40       * Will default to PHP time() value if null.
  41       */
  42      public static $timestamp = null;
  43  
  44      public static $supported_algs = array(
  45          'ES256' => array('openssl', 'SHA256'),
  46          'HS256' => array('hash_hmac', 'SHA256'),
  47          'HS384' => array('hash_hmac', 'SHA384'),
  48          'HS512' => array('hash_hmac', 'SHA512'),
  49          'RS256' => array('openssl', 'SHA256'),
  50          'RS384' => array('openssl', 'SHA384'),
  51          'RS512' => array('openssl', 'SHA512'),
  52      );
  53  
  54      /**
  55       * Decodes a JWT string into a PHP object.
  56       *
  57       * @param string                    $jwt            The JWT
  58       * @param string|array|resource     $key            The key, or map of keys.
  59       *                                                  If the algorithm used is asymmetric, this is the public key
  60       * @param array                     $allowed_algs   List of supported verification algorithms
  61       *                                                  Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
  62       *
  63       * @return object The JWT's payload as a PHP object
  64       *
  65       * @throws UnexpectedValueException     Provided JWT was invalid
  66       * @throws SignatureInvalidException    Provided JWT was invalid because the signature verification failed
  67       * @throws BeforeValidException         Provided JWT is trying to be used before it's eligible as defined by 'nbf'
  68       * @throws BeforeValidException         Provided JWT is trying to be used before it's been created as defined by 'iat'
  69       * @throws ExpiredException             Provided JWT has since expired, as defined by the 'exp' claim
  70       *
  71       * @uses jsonDecode
  72       * @uses urlsafeB64Decode
  73       */
  74      public static function decode($jwt, $key, array $allowed_algs = array())
  75      {
  76          $timestamp = \is_null(static::$timestamp) ? \time() : static::$timestamp;
  77  
  78          if (empty($key)) {
  79              throw new InvalidArgumentException('Key may not be empty');
  80          }
  81          $tks = \explode('.', $jwt);
  82          if (\count($tks) != 3) {
  83              throw new UnexpectedValueException('Wrong number of segments');
  84          }
  85          list($headb64, $bodyb64, $cryptob64) = $tks;
  86          if (null === ($header = static::jsonDecode(static::urlsafeB64Decode($headb64)))) {
  87              throw new UnexpectedValueException('Invalid header encoding');
  88          }
  89          if (null === $payload = static::jsonDecode(static::urlsafeB64Decode($bodyb64))) {
  90              throw new UnexpectedValueException('Invalid claims encoding');
  91          }
  92          if (false === ($sig = static::urlsafeB64Decode($cryptob64))) {
  93              throw new UnexpectedValueException('Invalid signature encoding');
  94          }
  95          if (empty($header->alg)) {
  96              throw new UnexpectedValueException('Empty algorithm');
  97          }
  98          if (empty(static::$supported_algs[$header->alg])) {
  99              throw new UnexpectedValueException('Algorithm not supported');
 100          }
 101          if (!\in_array($header->alg, $allowed_algs)) {
 102              throw new UnexpectedValueException('Algorithm not allowed');
 103          }
 104          if ($header->alg === 'ES256') {
 105              // OpenSSL expects an ASN.1 DER sequence for ES256 signatures
 106              $sig = self::signatureToDER($sig);
 107          }
 108  
 109          if (\is_array($key) || $key instanceof \ArrayAccess) {
 110              if (isset($header->kid)) {
 111                  if (!isset($key[$header->kid])) {
 112                      throw new UnexpectedValueException('"kid" invalid, unable to lookup correct key');
 113                  }
 114                  $key = $key[$header->kid];
 115              } else {
 116                  throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
 117              }
 118          }
 119  
 120          // Check the signature
 121          if (!static::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) {
 122              throw new SignatureInvalidException('Signature verification failed');
 123          }
 124  
 125          // Check the nbf if it is defined. This is the time that the
 126          // token can actually be used. If it's not yet that time, abort.
 127          if (isset($payload->nbf) && $payload->nbf > ($timestamp + static::$leeway)) {
 128              throw new BeforeValidException(
 129                  'Cannot handle token prior to ' . \date(DateTime::ISO8601, $payload->nbf)
 130              );
 131          }
 132  
 133          // Check that this token has been created before 'now'. This prevents
 134          // using tokens that have been created for later use (and haven't
 135          // correctly used the nbf claim).
 136          if (isset($payload->iat) && $payload->iat > ($timestamp + static::$leeway)) {
 137              throw new BeforeValidException(
 138                  'Cannot handle token prior to ' . \date(DateTime::ISO8601, $payload->iat)
 139              );
 140          }
 141  
 142          // Check if this token has expired.
 143          if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
 144              throw new ExpiredException('Expired token');
 145          }
 146  
 147          return $payload;
 148      }
 149  
 150      /**
 151       * Converts and signs a PHP object or array into a JWT string.
 152       *
 153       * @param object|array  $payload    PHP object or array
 154       * @param string        $key        The secret key.
 155       *                                  If the algorithm used is asymmetric, this is the private key
 156       * @param string        $alg        The signing algorithm.
 157       *                                  Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
 158       * @param mixed         $keyId
 159       * @param array         $head       An array with header elements to attach
 160       *
 161       * @return string A signed JWT
 162       *
 163       * @uses jsonEncode
 164       * @uses urlsafeB64Encode
 165       */
 166      public static function encode($payload, $key, $alg = 'HS256', $keyId = null, $head = null)
 167      {
 168          $header = array('typ' => 'JWT', 'alg' => $alg);
 169          if ($keyId !== null) {
 170              $header['kid'] = $keyId;
 171          }
 172          if (isset($head) && \is_array($head)) {
 173              $header = \array_merge($head, $header);
 174          }
 175          $segments = array();
 176          $segments[] = static::urlsafeB64Encode(static::jsonEncode($header));
 177          $segments[] = static::urlsafeB64Encode(static::jsonEncode($payload));
 178          $signing_input = \implode('.', $segments);
 179  
 180          $signature = static::sign($signing_input, $key, $alg);
 181          $segments[] = static::urlsafeB64Encode($signature);
 182  
 183          return \implode('.', $segments);
 184      }
 185  
 186      /**
 187       * Sign a string with a given key and algorithm.
 188       *
 189       * @param string            $msg    The message to sign
 190       * @param string|resource   $key    The secret key
 191       * @param string            $alg    The signing algorithm.
 192       *                                  Supported algorithms are 'ES256', 'HS256', 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
 193       *
 194       * @return string An encrypted message
 195       *
 196       * @throws DomainException Unsupported algorithm was specified
 197       */
 198      public static function sign($msg, $key, $alg = 'HS256')
 199      {
 200          if (empty(static::$supported_algs[$alg])) {
 201              throw new DomainException('Algorithm not supported');
 202          }
 203          list($function, $algorithm) = static::$supported_algs[$alg];
 204          switch ($function) {
 205              case 'hash_hmac':
 206                  return \hash_hmac($algorithm, $msg, $key, true);
 207              case 'openssl':
 208                  $signature = '';
 209                  $success = \openssl_sign($msg, $signature, $key, $algorithm);
 210                  if (!$success) {
 211                      throw new DomainException("OpenSSL unable to sign data");
 212                  } else {
 213                      if ($alg === 'ES256') {
 214                          $signature = self::signatureFromDER($signature, 256);
 215                      }
 216                      return $signature;
 217                  }
 218          }
 219      }
 220  
 221      /**
 222       * Verify a signature with the message, key and method. Not all methods
 223       * are symmetric, so we must have a separate verify and sign method.
 224       *
 225       * @param string            $msg        The original message (header and body)
 226       * @param string            $signature  The original signature
 227       * @param string|resource   $key        For HS*, a string key works. for RS*, must be a resource of an openssl public key
 228       * @param string            $alg        The algorithm
 229       *
 230       * @return bool
 231       *
 232       * @throws DomainException Invalid Algorithm or OpenSSL failure
 233       */
 234      private static function verify($msg, $signature, $key, $alg)
 235      {
 236          if (empty(static::$supported_algs[$alg])) {
 237              throw new DomainException('Algorithm not supported');
 238          }
 239  
 240          list($function, $algorithm) = static::$supported_algs[$alg];
 241          switch ($function) {
 242              case 'openssl':
 243                  $success = \openssl_verify($msg, $signature, $key, $algorithm);
 244                  if ($success === 1) {
 245                      return true;
 246                  } elseif ($success === 0) {
 247                      return false;
 248                  }
 249                  // returns 1 on success, 0 on failure, -1 on error.
 250                  throw new DomainException(
 251                      'OpenSSL error: ' . \openssl_error_string()
 252                  );
 253              case 'hash_hmac':
 254              default:
 255                  $hash = \hash_hmac($algorithm, $msg, $key, true);
 256                  if (\function_exists('hash_equals')) {
 257                      return \hash_equals($signature, $hash);
 258                  }
 259                  $len = \min(static::safeStrlen($signature), static::safeStrlen($hash));
 260  
 261                  $status = 0;
 262                  for ($i = 0; $i < $len; $i++) {
 263                      $status |= (\ord($signature[$i]) ^ \ord($hash[$i]));
 264                  }
 265                  $status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));
 266  
 267                  return ($status === 0);
 268          }
 269      }
 270  
 271      /**
 272       * Decode a JSON string into a PHP object.
 273       *
 274       * @param string $input JSON string
 275       *
 276       * @return object Object representation of JSON string
 277       *
 278       * @throws DomainException Provided string was invalid JSON
 279       */
 280      public static function jsonDecode($input)
 281      {
 282          if (\version_compare(PHP_VERSION, '5.4.0', '>=') && !(\defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
 283              /** In PHP >=5.4.0, json_decode() accepts an options parameter, that allows you
 284               * to specify that large ints (like Steam Transaction IDs) should be treated as
 285               * strings, rather than the PHP default behaviour of converting them to floats.
 286               */
 287              $obj = \json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
 288          } else {
 289              /** Not all servers will support that, however, so for older versions we must
 290               * manually detect large ints in the JSON string and quote them (thus converting
 291               *them to strings) before decoding, hence the preg_replace() call.
 292               */
 293              $max_int_length = \strlen((string) PHP_INT_MAX) - 1;
 294              $json_without_bigints = \preg_replace('/:\s*(-?\d{'.$max_int_length.',})/', ': "$1"', $input);
 295              $obj = \json_decode($json_without_bigints);
 296          }
 297  
 298          if ($errno = \json_last_error()) {
 299              static::handleJsonError($errno);
 300          } elseif ($obj === null && $input !== 'null') {
 301              throw new DomainException('Null result with non-null input');
 302          }
 303          return $obj;
 304      }
 305  
 306      /**
 307       * Encode a PHP object into a JSON string.
 308       *
 309       * @param object|array $input A PHP object or array
 310       *
 311       * @return string JSON representation of the PHP object or array
 312       *
 313       * @throws DomainException Provided object could not be encoded to valid JSON
 314       */
 315      public static function jsonEncode($input)
 316      {
 317          $json = \json_encode($input);
 318          if ($errno = \json_last_error()) {
 319              static::handleJsonError($errno);
 320          } elseif ($json === 'null' && $input !== null) {
 321              throw new DomainException('Null result with non-null input');
 322          }
 323          return $json;
 324      }
 325  
 326      /**
 327       * Decode a string with URL-safe Base64.
 328       *
 329       * @param string $input A Base64 encoded string
 330       *
 331       * @return string A decoded string
 332       */
 333      public static function urlsafeB64Decode($input)
 334      {
 335          $remainder = \strlen($input) % 4;
 336          if ($remainder) {
 337              $padlen = 4 - $remainder;
 338              $input .= \str_repeat('=', $padlen);
 339          }
 340          return \base64_decode(\strtr($input, '-_', '+/'));
 341      }
 342  
 343      /**
 344       * Encode a string with URL-safe Base64.
 345       *
 346       * @param string $input The string you want encoded
 347       *
 348       * @return string The base64 encode of what you passed in
 349       */
 350      public static function urlsafeB64Encode($input)
 351      {
 352          return \str_replace('=', '', \strtr(\base64_encode($input), '+/', '-_'));
 353      }
 354  
 355      /**
 356       * Helper method to create a JSON error.
 357       *
 358       * @param int $errno An error number from json_last_error()
 359       *
 360       * @return void
 361       */
 362      private static function handleJsonError($errno)
 363      {
 364          $messages = array(
 365              JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
 366              JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
 367              JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
 368              JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
 369              JSON_ERROR_UTF8 => 'Malformed UTF-8 characters' //PHP >= 5.3.3
 370          );
 371          throw new DomainException(
 372              isset($messages[$errno])
 373              ? $messages[$errno]
 374              : 'Unknown JSON error: ' . $errno
 375          );
 376      }
 377  
 378      /**
 379       * Get the number of bytes in cryptographic strings.
 380       *
 381       * @param string $str
 382       *
 383       * @return int
 384       */
 385      private static function safeStrlen($str)
 386      {
 387          if (\function_exists('mb_strlen')) {
 388              return \mb_strlen($str, '8bit');
 389          }
 390          return \strlen($str);
 391      }
 392  
 393      /**
 394       * Convert an ECDSA signature to an ASN.1 DER sequence
 395       *
 396       * @param   string $sig The ECDSA signature to convert
 397       * @return  string The encoded DER object
 398       */
 399      private static function signatureToDER($sig)
 400      {
 401          // Separate the signature into r-value and s-value
 402          list($r, $s) = \str_split($sig, (int) (\strlen($sig) / 2));
 403  
 404          // Trim leading zeros
 405          $r = \ltrim($r, "\x00");
 406          $s = \ltrim($s, "\x00");
 407  
 408          // Convert r-value and s-value from unsigned big-endian integers to
 409          // signed two's complement
 410          if (\ord($r[0]) > 0x7f) {
 411              $r = "\x00" . $r;
 412          }
 413          if (\ord($s[0]) > 0x7f) {
 414              $s = "\x00" . $s;
 415          }
 416  
 417          return self::encodeDER(
 418              self::ASN1_SEQUENCE,
 419              self::encodeDER(self::ASN1_INTEGER, $r) .
 420              self::encodeDER(self::ASN1_INTEGER, $s)
 421          );
 422      }
 423  
 424      /**
 425       * Encodes a value into a DER object.
 426       *
 427       * @param   int     $type DER tag
 428       * @param   string  $value the value to encode
 429       * @return  string  the encoded object
 430       */
 431      private static function encodeDER($type, $value)
 432      {
 433          $tag_header = 0;
 434          if ($type === self::ASN1_SEQUENCE) {
 435              $tag_header |= 0x20;
 436          }
 437  
 438          // Type
 439          $der = \chr($tag_header | $type);
 440  
 441          // Length
 442          $der .= \chr(\strlen($value));
 443  
 444          return $der . $value;
 445      }
 446  
 447      /**
 448       * Encodes signature from a DER object.
 449       *
 450       * @param   string  $der binary signature in DER format
 451       * @param   int     $keySize the number of bits in the key
 452       * @return  string  the signature
 453       */
 454      private static function signatureFromDER($der, $keySize)
 455      {
 456          // OpenSSL returns the ECDSA signatures as a binary ASN.1 DER SEQUENCE
 457          list($offset, $_) = self::readDER($der);
 458          list($offset, $r) = self::readDER($der, $offset);
 459          list($offset, $s) = self::readDER($der, $offset);
 460  
 461          // Convert r-value and s-value from signed two's compliment to unsigned
 462          // big-endian integers
 463          $r = \ltrim($r, "\x00");
 464          $s = \ltrim($s, "\x00");
 465  
 466          // Pad out r and s so that they are $keySize bits long
 467          $r = \str_pad($r, $keySize / 8, "\x00", STR_PAD_LEFT);
 468          $s = \str_pad($s, $keySize / 8, "\x00", STR_PAD_LEFT);
 469  
 470          return $r . $s;
 471      }
 472  
 473      /**
 474       * Reads binary DER-encoded data and decodes into a single object
 475       *
 476       * @param string $der the binary data in DER format
 477       * @param int $offset the offset of the data stream containing the object
 478       * to decode
 479       * @return array [$offset, $data] the new offset and the decoded object
 480       */
 481      private static function readDER($der, $offset = 0)
 482      {
 483          $pos = $offset;
 484          $size = \strlen($der);
 485          $constructed = (\ord($der[$pos]) >> 5) & 0x01;
 486          $type = \ord($der[$pos++]) & 0x1f;
 487  
 488          // Length
 489          $len = \ord($der[$pos++]);
 490          if ($len & 0x80) {
 491              $n = $len & 0x1f;
 492              $len = 0;
 493              while ($n-- && $pos < $size) {
 494                  $len = ($len << 8) | \ord($der[$pos++]);
 495              }
 496          }
 497  
 498          // Value
 499          if ($type == self::ASN1_BIT_STRING) {
 500              $pos++; // Skip the first contents octet (padding indicator)
 501              $data = \substr($der, $pos, $len - 1);
 502              $pos += $len - 1;
 503          } elseif (!$constructed) {
 504              $data = \substr($der, $pos, $len);
 505              $pos += $len;
 506          } else {
 507              $data = null;
 508          }
 509  
 510          return array($pos, $data);
 511      }
 512  }