source: vendor/firebase/php-jwt/src/JWT.php@ e3d4e0a

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1<?php
2
3namespace Firebase\JWT;
4
5use ArrayAccess;
6use DateTime;
7use DomainException;
8use Exception;
9use InvalidArgumentException;
10use OpenSSLAsymmetricKey;
11use OpenSSLCertificate;
12use stdClass;
13use UnexpectedValueException;
14
15/**
16 * JSON Web Token implementation, based on this spec:
17 * https://tools.ietf.org/html/rfc7519
18 *
19 * PHP version 5
20 *
21 * @category Authentication
22 * @package Authentication_JWT
23 * @author Neuman Vong <neuman@twilio.com>
24 * @author Anant Narayanan <anant@php.net>
25 * @license http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
26 * @link https://github.com/firebase/php-jwt
27 */
28class JWT
29{
30 private const ASN1_INTEGER = 0x02;
31 private const ASN1_SEQUENCE = 0x10;
32 private const ASN1_BIT_STRING = 0x03;
33
34 /**
35 * When checking nbf, iat or expiration times,
36 * we want to provide some extra leeway time to
37 * account for clock skew.
38 *
39 * @var int
40 */
41 public static $leeway = 0;
42
43 /**
44 * Allow the current timestamp to be specified.
45 * Useful for fixing a value within unit testing.
46 * Will default to PHP time() value if null.
47 *
48 * @var ?int
49 */
50 public static $timestamp = null;
51
52 /**
53 * @var array<string, string[]>
54 */
55 public static $supported_algs = [
56 'ES384' => ['openssl', 'SHA384'],
57 'ES256' => ['openssl', 'SHA256'],
58 'ES256K' => ['openssl', 'SHA256'],
59 'HS256' => ['hash_hmac', 'SHA256'],
60 'HS384' => ['hash_hmac', 'SHA384'],
61 'HS512' => ['hash_hmac', 'SHA512'],
62 'RS256' => ['openssl', 'SHA256'],
63 'RS384' => ['openssl', 'SHA384'],
64 'RS512' => ['openssl', 'SHA512'],
65 'EdDSA' => ['sodium_crypto', 'EdDSA'],
66 ];
67
68 /**
69 * Decodes a JWT string into a PHP object.
70 *
71 * @param string $jwt The JWT
72 * @param Key|ArrayAccess<string,Key>|array<string,Key> $keyOrKeyArray The Key or associative array of key IDs
73 * (kid) to Key objects.
74 * If the algorithm used is asymmetric, this is
75 * the public key.
76 * Each Key object contains an algorithm and
77 * matching key.
78 * Supported algorithms are 'ES384','ES256',
79 * 'HS256', 'HS384', 'HS512', 'RS256', 'RS384'
80 * and 'RS512'.
81 * @param stdClass $headers Optional. Populates stdClass with headers.
82 *
83 * @return stdClass The JWT's payload as a PHP object
84 *
85 * @throws InvalidArgumentException Provided key/key-array was empty or malformed
86 * @throws DomainException Provided JWT is malformed
87 * @throws UnexpectedValueException Provided JWT was invalid
88 * @throws SignatureInvalidException Provided JWT was invalid because the signature verification failed
89 * @throws BeforeValidException Provided JWT is trying to be used before it's eligible as defined by 'nbf'
90 * @throws BeforeValidException Provided JWT is trying to be used before it's been created as defined by 'iat'
91 * @throws ExpiredException Provided JWT has since expired, as defined by the 'exp' claim
92 *
93 * @uses jsonDecode
94 * @uses urlsafeB64Decode
95 */
96 public static function decode(
97 string $jwt,
98 $keyOrKeyArray,
99 ?stdClass &$headers = null
100 ): stdClass {
101 // Validate JWT
102 $timestamp = \is_null(static::$timestamp) ? \time() : static::$timestamp;
103
104 if (empty($keyOrKeyArray)) {
105 throw new InvalidArgumentException('Key may not be empty');
106 }
107 $tks = \explode('.', $jwt);
108 if (\count($tks) !== 3) {
109 throw new UnexpectedValueException('Wrong number of segments');
110 }
111 list($headb64, $bodyb64, $cryptob64) = $tks;
112 $headerRaw = static::urlsafeB64Decode($headb64);
113 if (null === ($header = static::jsonDecode($headerRaw))) {
114 throw new UnexpectedValueException('Invalid header encoding');
115 }
116 if ($headers !== null) {
117 $headers = $header;
118 }
119 $payloadRaw = static::urlsafeB64Decode($bodyb64);
120 if (null === ($payload = static::jsonDecode($payloadRaw))) {
121 throw new UnexpectedValueException('Invalid claims encoding');
122 }
123 if (\is_array($payload)) {
124 // prevent PHP Fatal Error in edge-cases when payload is empty array
125 $payload = (object) $payload;
126 }
127 if (!$payload instanceof stdClass) {
128 throw new UnexpectedValueException('Payload must be a JSON object');
129 }
130 $sig = static::urlsafeB64Decode($cryptob64);
131 if (empty($header->alg)) {
132 throw new UnexpectedValueException('Empty algorithm');
133 }
134 if (empty(static::$supported_algs[$header->alg])) {
135 throw new UnexpectedValueException('Algorithm not supported');
136 }
137
138 $key = self::getKey($keyOrKeyArray, property_exists($header, 'kid') ? $header->kid : null);
139
140 // Check the algorithm
141 if (!self::constantTimeEquals($key->getAlgorithm(), $header->alg)) {
142 // See issue #351
143 throw new UnexpectedValueException('Incorrect key for this algorithm');
144 }
145 if (\in_array($header->alg, ['ES256', 'ES256K', 'ES384'], true)) {
146 // OpenSSL expects an ASN.1 DER sequence for ES256/ES256K/ES384 signatures
147 $sig = self::signatureToDER($sig);
148 }
149 if (!self::verify("{$headb64}.{$bodyb64}", $sig, $key->getKeyMaterial(), $header->alg)) {
150 throw new SignatureInvalidException('Signature verification failed');
151 }
152
153 // Check the nbf if it is defined. This is the time that the
154 // token can actually be used. If it's not yet that time, abort.
155 if (isset($payload->nbf) && floor($payload->nbf) > ($timestamp + static::$leeway)) {
156 $ex = new BeforeValidException(
157 'Cannot handle token with nbf prior to ' . \date(DateTime::ISO8601, (int) $payload->nbf)
158 );
159 $ex->setPayload($payload);
160 throw $ex;
161 }
162
163 // Check that this token has been created before 'now'. This prevents
164 // using tokens that have been created for later use (and haven't
165 // correctly used the nbf claim).
166 if (!isset($payload->nbf) && isset($payload->iat) && floor($payload->iat) > ($timestamp + static::$leeway)) {
167 $ex = new BeforeValidException(
168 'Cannot handle token with iat prior to ' . \date(DateTime::ISO8601, (int) $payload->iat)
169 );
170 $ex->setPayload($payload);
171 throw $ex;
172 }
173
174 // Check if this token has expired.
175 if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
176 $ex = new ExpiredException('Expired token');
177 $ex->setPayload($payload);
178 throw $ex;
179 }
180
181 return $payload;
182 }
183
184 /**
185 * Converts and signs a PHP array into a JWT string.
186 *
187 * @param array<mixed> $payload PHP array
188 * @param string|resource|OpenSSLAsymmetricKey|OpenSSLCertificate $key The secret key.
189 * @param string $alg Supported algorithms are 'ES384','ES256', 'ES256K', 'HS256',
190 * 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
191 * @param string $keyId
192 * @param array<string, string> $head An array with header elements to attach
193 *
194 * @return string A signed JWT
195 *
196 * @uses jsonEncode
197 * @uses urlsafeB64Encode
198 */
199 public static function encode(
200 array $payload,
201 $key,
202 string $alg,
203 ?string $keyId = null,
204 ?array $head = null
205 ): string {
206 $header = ['typ' => 'JWT'];
207 if (isset($head)) {
208 $header = \array_merge($header, $head);
209 }
210 $header['alg'] = $alg;
211 if ($keyId !== null) {
212 $header['kid'] = $keyId;
213 }
214 $segments = [];
215 $segments[] = static::urlsafeB64Encode((string) static::jsonEncode($header));
216 $segments[] = static::urlsafeB64Encode((string) static::jsonEncode($payload));
217 $signing_input = \implode('.', $segments);
218
219 $signature = static::sign($signing_input, $key, $alg);
220 $segments[] = static::urlsafeB64Encode($signature);
221
222 return \implode('.', $segments);
223 }
224
225 /**
226 * Sign a string with a given key and algorithm.
227 *
228 * @param string $msg The message to sign
229 * @param string|resource|OpenSSLAsymmetricKey|OpenSSLCertificate $key The secret key.
230 * @param string $alg Supported algorithms are 'EdDSA', 'ES384', 'ES256', 'ES256K', 'HS256',
231 * 'HS384', 'HS512', 'RS256', 'RS384', and 'RS512'
232 *
233 * @return string An encrypted message
234 *
235 * @throws DomainException Unsupported algorithm or bad key was specified
236 */
237 public static function sign(
238 string $msg,
239 $key,
240 string $alg
241 ): string {
242 if (empty(static::$supported_algs[$alg])) {
243 throw new DomainException('Algorithm not supported');
244 }
245 list($function, $algorithm) = static::$supported_algs[$alg];
246 switch ($function) {
247 case 'hash_hmac':
248 if (!\is_string($key)) {
249 throw new InvalidArgumentException('key must be a string when using hmac');
250 }
251 return \hash_hmac($algorithm, $msg, $key, true);
252 case 'openssl':
253 $signature = '';
254 if (!\is_resource($key) && !openssl_pkey_get_private($key)) {
255 throw new DomainException('OpenSSL unable to validate key');
256 }
257 $success = \openssl_sign($msg, $signature, $key, $algorithm); // @phpstan-ignore-line
258 if (!$success) {
259 throw new DomainException('OpenSSL unable to sign data');
260 }
261 if ($alg === 'ES256' || $alg === 'ES256K') {
262 $signature = self::signatureFromDER($signature, 256);
263 } elseif ($alg === 'ES384') {
264 $signature = self::signatureFromDER($signature, 384);
265 }
266 return $signature;
267 case 'sodium_crypto':
268 if (!\function_exists('sodium_crypto_sign_detached')) {
269 throw new DomainException('libsodium is not available');
270 }
271 if (!\is_string($key)) {
272 throw new InvalidArgumentException('key must be a string when using EdDSA');
273 }
274 try {
275 // The last non-empty line is used as the key.
276 $lines = array_filter(explode("\n", $key));
277 $key = base64_decode((string) end($lines));
278 if (\strlen($key) === 0) {
279 throw new DomainException('Key cannot be empty string');
280 }
281 return sodium_crypto_sign_detached($msg, $key);
282 } catch (Exception $e) {
283 throw new DomainException($e->getMessage(), 0, $e);
284 }
285 }
286
287 throw new DomainException('Algorithm not supported');
288 }
289
290 /**
291 * Verify a signature with the message, key and method. Not all methods
292 * are symmetric, so we must have a separate verify and sign method.
293 *
294 * @param string $msg The original message (header and body)
295 * @param string $signature The original signature
296 * @param string|resource|OpenSSLAsymmetricKey|OpenSSLCertificate $keyMaterial For Ed*, ES*, HS*, a string key works. for RS*, must be an instance of OpenSSLAsymmetricKey
297 * @param string $alg The algorithm
298 *
299 * @return bool
300 *
301 * @throws DomainException Invalid Algorithm, bad key, or OpenSSL failure
302 */
303 private static function verify(
304 string $msg,
305 string $signature,
306 $keyMaterial,
307 string $alg
308 ): bool {
309 if (empty(static::$supported_algs[$alg])) {
310 throw new DomainException('Algorithm not supported');
311 }
312
313 list($function, $algorithm) = static::$supported_algs[$alg];
314 switch ($function) {
315 case 'openssl':
316 $success = \openssl_verify($msg, $signature, $keyMaterial, $algorithm); // @phpstan-ignore-line
317 if ($success === 1) {
318 return true;
319 }
320 if ($success === 0) {
321 return false;
322 }
323 // returns 1 on success, 0 on failure, -1 on error.
324 throw new DomainException(
325 'OpenSSL error: ' . \openssl_error_string()
326 );
327 case 'sodium_crypto':
328 if (!\function_exists('sodium_crypto_sign_verify_detached')) {
329 throw new DomainException('libsodium is not available');
330 }
331 if (!\is_string($keyMaterial)) {
332 throw new InvalidArgumentException('key must be a string when using EdDSA');
333 }
334 try {
335 // The last non-empty line is used as the key.
336 $lines = array_filter(explode("\n", $keyMaterial));
337 $key = base64_decode((string) end($lines));
338 if (\strlen($key) === 0) {
339 throw new DomainException('Key cannot be empty string');
340 }
341 if (\strlen($signature) === 0) {
342 throw new DomainException('Signature cannot be empty string');
343 }
344 return sodium_crypto_sign_verify_detached($signature, $msg, $key);
345 } catch (Exception $e) {
346 throw new DomainException($e->getMessage(), 0, $e);
347 }
348 case 'hash_hmac':
349 default:
350 if (!\is_string($keyMaterial)) {
351 throw new InvalidArgumentException('key must be a string when using hmac');
352 }
353 $hash = \hash_hmac($algorithm, $msg, $keyMaterial, true);
354 return self::constantTimeEquals($hash, $signature);
355 }
356 }
357
358 /**
359 * Decode a JSON string into a PHP object.
360 *
361 * @param string $input JSON string
362 *
363 * @return mixed The decoded JSON string
364 *
365 * @throws DomainException Provided string was invalid JSON
366 */
367 public static function jsonDecode(string $input)
368 {
369 $obj = \json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
370
371 if ($errno = \json_last_error()) {
372 self::handleJsonError($errno);
373 } elseif ($obj === null && $input !== 'null') {
374 throw new DomainException('Null result with non-null input');
375 }
376 return $obj;
377 }
378
379 /**
380 * Encode a PHP array into a JSON string.
381 *
382 * @param array<mixed> $input A PHP array
383 *
384 * @return string JSON representation of the PHP array
385 *
386 * @throws DomainException Provided object could not be encoded to valid JSON
387 */
388 public static function jsonEncode(array $input): string
389 {
390 $json = \json_encode($input, \JSON_UNESCAPED_SLASHES);
391 if ($errno = \json_last_error()) {
392 self::handleJsonError($errno);
393 } elseif ($json === 'null') {
394 throw new DomainException('Null result with non-null input');
395 }
396 if ($json === false) {
397 throw new DomainException('Provided object could not be encoded to valid JSON');
398 }
399 return $json;
400 }
401
402 /**
403 * Decode a string with URL-safe Base64.
404 *
405 * @param string $input A Base64 encoded string
406 *
407 * @return string A decoded string
408 *
409 * @throws InvalidArgumentException invalid base64 characters
410 */
411 public static function urlsafeB64Decode(string $input): string
412 {
413 return \base64_decode(self::convertBase64UrlToBase64($input));
414 }
415
416 /**
417 * Convert a string in the base64url (URL-safe Base64) encoding to standard base64.
418 *
419 * @param string $input A Base64 encoded string with URL-safe characters (-_ and no padding)
420 *
421 * @return string A Base64 encoded string with standard characters (+/) and padding (=), when
422 * needed.
423 *
424 * @see https://www.rfc-editor.org/rfc/rfc4648
425 */
426 public static function convertBase64UrlToBase64(string $input): string
427 {
428 $remainder = \strlen($input) % 4;
429 if ($remainder) {
430 $padlen = 4 - $remainder;
431 $input .= \str_repeat('=', $padlen);
432 }
433 return \strtr($input, '-_', '+/');
434 }
435
436 /**
437 * Encode a string with URL-safe Base64.
438 *
439 * @param string $input The string you want encoded
440 *
441 * @return string The base64 encode of what you passed in
442 */
443 public static function urlsafeB64Encode(string $input): string
444 {
445 return \str_replace('=', '', \strtr(\base64_encode($input), '+/', '-_'));
446 }
447
448
449 /**
450 * Determine if an algorithm has been provided for each Key
451 *
452 * @param Key|ArrayAccess<string,Key>|array<string,Key> $keyOrKeyArray
453 * @param string|null $kid
454 *
455 * @throws UnexpectedValueException
456 *
457 * @return Key
458 */
459 private static function getKey(
460 $keyOrKeyArray,
461 ?string $kid
462 ): Key {
463 if ($keyOrKeyArray instanceof Key) {
464 return $keyOrKeyArray;
465 }
466
467 if (empty($kid) && $kid !== '0') {
468 throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
469 }
470
471 if ($keyOrKeyArray instanceof CachedKeySet) {
472 // Skip "isset" check, as this will automatically refresh if not set
473 return $keyOrKeyArray[$kid];
474 }
475
476 if (!isset($keyOrKeyArray[$kid])) {
477 throw new UnexpectedValueException('"kid" invalid, unable to lookup correct key');
478 }
479
480 return $keyOrKeyArray[$kid];
481 }
482
483 /**
484 * @param string $left The string of known length to compare against
485 * @param string $right The user-supplied string
486 * @return bool
487 */
488 public static function constantTimeEquals(string $left, string $right): bool
489 {
490 if (\function_exists('hash_equals')) {
491 return \hash_equals($left, $right);
492 }
493 $len = \min(self::safeStrlen($left), self::safeStrlen($right));
494
495 $status = 0;
496 for ($i = 0; $i < $len; $i++) {
497 $status |= (\ord($left[$i]) ^ \ord($right[$i]));
498 }
499 $status |= (self::safeStrlen($left) ^ self::safeStrlen($right));
500
501 return ($status === 0);
502 }
503
504 /**
505 * Helper method to create a JSON error.
506 *
507 * @param int $errno An error number from json_last_error()
508 *
509 * @throws DomainException
510 *
511 * @return void
512 */
513 private static function handleJsonError(int $errno): void
514 {
515 $messages = [
516 JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
517 JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON',
518 JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
519 JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON',
520 JSON_ERROR_UTF8 => 'Malformed UTF-8 characters' //PHP >= 5.3.3
521 ];
522 throw new DomainException(
523 isset($messages[$errno])
524 ? $messages[$errno]
525 : 'Unknown JSON error: ' . $errno
526 );
527 }
528
529 /**
530 * Get the number of bytes in cryptographic strings.
531 *
532 * @param string $str
533 *
534 * @return int
535 */
536 private static function safeStrlen(string $str): int
537 {
538 if (\function_exists('mb_strlen')) {
539 return \mb_strlen($str, '8bit');
540 }
541 return \strlen($str);
542 }
543
544 /**
545 * Convert an ECDSA signature to an ASN.1 DER sequence
546 *
547 * @param string $sig The ECDSA signature to convert
548 * @return string The encoded DER object
549 */
550 private static function signatureToDER(string $sig): string
551 {
552 // Separate the signature into r-value and s-value
553 $length = max(1, (int) (\strlen($sig) / 2));
554 list($r, $s) = \str_split($sig, $length);
555
556 // Trim leading zeros
557 $r = \ltrim($r, "\x00");
558 $s = \ltrim($s, "\x00");
559
560 // Convert r-value and s-value from unsigned big-endian integers to
561 // signed two's complement
562 if (\ord($r[0]) > 0x7f) {
563 $r = "\x00" . $r;
564 }
565 if (\ord($s[0]) > 0x7f) {
566 $s = "\x00" . $s;
567 }
568
569 return self::encodeDER(
570 self::ASN1_SEQUENCE,
571 self::encodeDER(self::ASN1_INTEGER, $r) .
572 self::encodeDER(self::ASN1_INTEGER, $s)
573 );
574 }
575
576 /**
577 * Encodes a value into a DER object.
578 *
579 * @param int $type DER tag
580 * @param string $value the value to encode
581 *
582 * @return string the encoded object
583 */
584 private static function encodeDER(int $type, string $value): string
585 {
586 $tag_header = 0;
587 if ($type === self::ASN1_SEQUENCE) {
588 $tag_header |= 0x20;
589 }
590
591 // Type
592 $der = \chr($tag_header | $type);
593
594 // Length
595 $der .= \chr(\strlen($value));
596
597 return $der . $value;
598 }
599
600 /**
601 * Encodes signature from a DER object.
602 *
603 * @param string $der binary signature in DER format
604 * @param int $keySize the number of bits in the key
605 *
606 * @return string the signature
607 */
608 private static function signatureFromDER(string $der, int $keySize): string
609 {
610 // OpenSSL returns the ECDSA signatures as a binary ASN.1 DER SEQUENCE
611 list($offset, $_) = self::readDER($der);
612 list($offset, $r) = self::readDER($der, $offset);
613 list($offset, $s) = self::readDER($der, $offset);
614
615 // Convert r-value and s-value from signed two's compliment to unsigned
616 // big-endian integers
617 $r = \ltrim($r, "\x00");
618 $s = \ltrim($s, "\x00");
619
620 // Pad out r and s so that they are $keySize bits long
621 $r = \str_pad($r, $keySize / 8, "\x00", STR_PAD_LEFT);
622 $s = \str_pad($s, $keySize / 8, "\x00", STR_PAD_LEFT);
623
624 return $r . $s;
625 }
626
627 /**
628 * Reads binary DER-encoded data and decodes into a single object
629 *
630 * @param string $der the binary data in DER format
631 * @param int $offset the offset of the data stream containing the object
632 * to decode
633 *
634 * @return array{int, string|null} the new offset and the decoded object
635 */
636 private static function readDER(string $der, int $offset = 0): array
637 {
638 $pos = $offset;
639 $size = \strlen($der);
640 $constructed = (\ord($der[$pos]) >> 5) & 0x01;
641 $type = \ord($der[$pos++]) & 0x1f;
642
643 // Length
644 $len = \ord($der[$pos++]);
645 if ($len & 0x80) {
646 $n = $len & 0x1f;
647 $len = 0;
648 while ($n-- && $pos < $size) {
649 $len = ($len << 8) | \ord($der[$pos++]);
650 }
651 }
652
653 // Value
654 if ($type === self::ASN1_BIT_STRING) {
655 $pos++; // Skip the first contents octet (padding indicator)
656 $data = \substr($der, $pos, $len - 1);
657 $pos += $len - 1;
658 } elseif (!$constructed) {
659 $data = \substr($der, $pos, $len);
660 $pos += $len;
661 } else {
662 $data = null;
663 }
664
665 return [$pos, $data];
666 }
667}
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