Passed
Push — 1.11.x ( 31fff3...86e7ae )
by Yannick
15:37 queued 10s
created

JWT::decode()   D

Complexity

Conditions 20
Paths 38

Size

Total Lines 68
Code Lines 36

Duplication

Lines 0
Ratio 0 %

Importance

Changes 1
Bugs 0 Features 0
Metric Value
cc 20
eloc 36
nc 38
nop 3
dl 0
loc 68
rs 4.1666
c 1
b 0
f 0

How to fix   Long Method    Complexity   

Long Method

Small methods make your code easier to understand, in particular if combined with a good name. Besides, if your method is small, finding a good name is usually much easier.

For example, if you find yourself adding comments to a method's body, this is usually a good sign to extract the commented part to a new method, and use the comment as a starting point when coming up with a good name for this new method.

Commonly applied refactorings include:

1
<?php
2
3
namespace Firebase\JWT;
4
use \DomainException;
5
use \InvalidArgumentException;
6
use \UnexpectedValueException;
7
use \DateTime;
8
9
/**
10
 * JSON Web Token implementation, based on this spec:
11
 * http://tools.ietf.org/html/draft-ietf-oauth-json-web-token-06
12
 *
13
 * PHP version 5
14
 *
15
 * @category Authentication
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 * @package  Authentication_JWT
17
 * @author   Neuman Vong <[email protected]>
18
 * @author   Anant Narayanan <[email protected]>
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 * @license  http://opensource.org/licenses/BSD-3-Clause 3-clause BSD
20
 * @link     https://github.com/firebase/php-jwt
21
 */
22
class JWT
23
{
24
25
    /**
26
     * When checking nbf, iat or expiration times,
27
     * we want to provide some extra leeway time to
28
     * account for clock skew.
29
     */
30
    public static $leeway = 0;
31
32
    /**
33
     * Allow the current timestamp to be specified.
34
     * Useful for fixing a value within unit testing.
35
     *
36
     * Will default to PHP time() value if null.
37
     */
38
    public static $timestamp = null;
39
40
    public static $supported_algs = array(
41
        'HS256' => array('hash_hmac', 'SHA256'),
42
        'HS512' => array('hash_hmac', 'SHA512'),
43
        'HS384' => array('hash_hmac', 'SHA384'),
44
        'RS256' => array('openssl', 'SHA256'),
45
    );
46
47
    /**
48
     * Decodes a JWT string into a PHP object.
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     *
50
     * @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
53
     * @param array         $allowed_algs   List of supported verification algorithms
54
     *                                      Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
55
     *
56
     * @return object The JWT's payload as a PHP object
57
     *
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     * @throws UnexpectedValueException     Provided JWT was invalid
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     * @throws SignatureInvalidException    Provided JWT was invalid because the signature verification failed
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     * @throws BeforeValidException         Provided JWT is trying to be used before it's eligible as defined by 'nbf'
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     * @throws BeforeValidException         Provided JWT is trying to be used before it's been created as defined by 'iat'
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     * @throws ExpiredException             Provided JWT has since expired, as defined by the 'exp' claim
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     *
64
     * @uses jsonDecode
65
     * @uses urlsafeB64Decode
66
     */
67
    public static function decode($jwt, $key, $allowed_algs = array())
68
    {
69
        $timestamp = is_null(static::$timestamp) ? time() : static::$timestamp;
70
71
        if (empty($key)) {
72
            throw new InvalidArgumentException('Key may not be empty');
73
        }
74
        if (!is_array($allowed_algs)) {
75
            throw new InvalidArgumentException('Algorithm not allowed');
76
        }
77
        $tks = explode('.', $jwt);
78
        if (count($tks) != 3) {
79
            throw new UnexpectedValueException('Wrong number of segments');
80
        }
81
        list($headb64, $bodyb64, $cryptob64) = $tks;
82
        if (null === ($header = static::jsonDecode(static::urlsafeB64Decode($headb64)))) {
83
            throw new UnexpectedValueException('Invalid header encoding');
84
        }
85
        if (null === $payload = static::jsonDecode(static::urlsafeB64Decode($bodyb64))) {
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            throw new UnexpectedValueException('Invalid claims encoding');
87
        }
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        $sig = static::urlsafeB64Decode($cryptob64);
89
        
90
        if (empty($header->alg)) {
91
            throw new UnexpectedValueException('Empty algorithm');
92
        }
93
        if (empty(static::$supported_algs[$header->alg])) {
94
            throw new UnexpectedValueException('Algorithm not supported');
95
        }
96
        if (!in_array($header->alg, $allowed_algs)) {
97
            throw new UnexpectedValueException('Algorithm not allowed');
98
        }
99
        if (is_array($key) || $key instanceof \ArrayAccess) {
100
            if (isset($header->kid)) {
101
                $key = $key[$header->kid];
102
            } else {
103
                throw new UnexpectedValueException('"kid" empty, unable to lookup correct key');
104
            }
105
        }
106
107
        // Check the signature
108
        if (!static::verify("$headb64.$bodyb64", $sig, $key, $header->alg)) {
109
            throw new SignatureInvalidException('Signature verification failed');
110
        }
111
112
        // Check if the nbf if it is defined. This is the time that the
113
        // token can actually be used. If it's not yet that time, abort.
114
        if (isset($payload->nbf) && $payload->nbf > ($timestamp + static::$leeway)) {
115
            throw new BeforeValidException(
116
                'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->nbf)
117
            );
118
        }
119
120
        // Check that this token has been created before 'now'. This prevents
121
        // using tokens that have been created for later use (and haven't
122
        // correctly used the nbf claim).
123
        if (isset($payload->iat) && $payload->iat > ($timestamp + static::$leeway)) {
124
            throw new BeforeValidException(
125
                'Cannot handle token prior to ' . date(DateTime::ISO8601, $payload->iat)
126
            );
127
        }
128
129
        // Check if this token has expired.
130
        if (isset($payload->exp) && ($timestamp - static::$leeway) >= $payload->exp) {
131
            throw new ExpiredException('Expired token');
132
        }
133
134
        return $payload;
135
    }
136
137
    /**
138
     * Converts and signs a PHP object or array into a JWT string.
139
     *
140
     * @param object|array  $payload    PHP object or array
141
     * @param string        $key        The secret key.
142
     *                                  If the algorithm used is asymmetric, this is the private key
143
     * @param string        $alg        The signing algorithm.
144
     *                                  Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
145
     * @param mixed         $keyId
146
     * @param array         $head       An array with header elements to attach
147
     *
148
     * @return string A signed JWT
149
     *
150
     * @uses jsonEncode
151
     * @uses urlsafeB64Encode
152
     */
153
    public static function encode($payload, $key, $alg = 'HS256', $keyId = null, $head = null)
154
    {
155
        $header = array('typ' => 'JWT', 'alg' => $alg);
156
        if ($keyId !== null) {
157
            $header['kid'] = $keyId;
158
        }
159
        if ( isset($head) && is_array($head) ) {
160
            $header = array_merge($head, $header);
161
        }
162
        $segments = array();
163
        $segments[] = static::urlsafeB64Encode(static::jsonEncode($header));
164
        $segments[] = static::urlsafeB64Encode(static::jsonEncode($payload));
165
        $signing_input = implode('.', $segments);
166
167
        $signature = static::sign($signing_input, $key, $alg);
168
        $segments[] = static::urlsafeB64Encode($signature);
169
170
        return implode('.', $segments);
171
    }
172
173
    /**
174
     * Sign a string with a given key and algorithm.
175
     *
176
     * @param string            $msg    The message to sign
177
     * @param string|resource   $key    The secret key
178
     * @param string            $alg    The signing algorithm.
179
     *                                  Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'
180
     *
181
     * @return string An encrypted message
182
     *
183
     * @throws DomainException Unsupported algorithm was specified
184
     */
185
    public static function sign($msg, $key, $alg = 'HS256')
186
    {
187
        if (empty(static::$supported_algs[$alg])) {
188
            throw new DomainException('Algorithm not supported');
189
        }
190
        list($function, $algorithm) = static::$supported_algs[$alg];
191
        switch($function) {
192
            case 'hash_hmac':
193
                return hash_hmac($algorithm, $msg, $key, true);
194
            case 'openssl':
195
                $signature = '';
196
                $success = openssl_sign($msg, $signature, $key, $algorithm);
197
                if (!$success) {
198
                    throw new DomainException("OpenSSL unable to sign data");
199
                } else {
200
                    return $signature;
201
                }
202
        }
203
    }
204
205
    /**
206
     * Verify a signature with the message, key and method. Not all methods
207
     * are symmetric, so we must have a separate verify and sign method.
208
     *
209
     * @param string            $msg        The original message (header and body)
210
     * @param string            $signature  The original signature
211
     * @param string|resource   $key        For HS*, a string key works. for RS*, must be a resource of an openssl public key
212
     * @param string            $alg        The algorithm
213
     *
214
     * @return bool
215
     *
216
     * @throws DomainException Invalid Algorithm or OpenSSL failure
217
     */
218
    private static function verify($msg, $signature, $key, $alg)
219
    {
220
        if (empty(static::$supported_algs[$alg])) {
221
            throw new DomainException('Algorithm not supported');
222
        }
223
224
        list($function, $algorithm) = static::$supported_algs[$alg];
225
        switch($function) {
226
            case 'openssl':
227
                $success = openssl_verify($msg, $signature, $key, $algorithm);
228
                if (!$success) {
229
                    throw new DomainException("OpenSSL unable to verify data: " . openssl_error_string());
230
                } else {
231
                    return $signature;
232
                }
233
            case 'hash_hmac':
234
            default:
235
                $hash = hash_hmac($algorithm, $msg, $key, true);
236
                if (function_exists('hash_equals')) {
237
                    return hash_equals($signature, $hash);
238
                }
239
                $len = min(static::safeStrlen($signature), static::safeStrlen($hash));
240
241
                $status = 0;
242
                for ($i = 0; $i < $len; $i++) {
243
                    $status |= (ord($signature[$i]) ^ ord($hash[$i]));
244
                }
245
                $status |= (static::safeStrlen($signature) ^ static::safeStrlen($hash));
246
247
                return ($status === 0);
248
        }
249
    }
250
251
    /**
252
     * Decode a JSON string into a PHP object.
253
     *
254
     * @param string $input JSON string
255
     *
256
     * @return object Object representation of JSON string
257
     *
258
     * @throws DomainException Provided string was invalid JSON
259
     */
260
    public static function jsonDecode($input)
261
    {
262
        if (version_compare(PHP_VERSION, '5.4.0', '>=') && !(defined('JSON_C_VERSION') && PHP_INT_SIZE > 4)) {
263
            /** In PHP >=5.4.0, json_decode() accepts an options parameter, that allows you
264
             * to specify that large ints (like Steam Transaction IDs) should be treated as
265
             * strings, rather than the PHP default behaviour of converting them to floats.
266
             */
267
            $obj = json_decode($input, false, 512, JSON_BIGINT_AS_STRING);
268
        } else {
269
            /** Not all servers will support that, however, so for older versions we must
270
             * manually detect large ints in the JSON string and quote them (thus converting
271
             *them to strings) before decoding, hence the preg_replace() call.
272
             */
273
            $max_int_length = strlen((string) PHP_INT_MAX) - 1;
274
            $json_without_bigints = preg_replace('/:\s*(-?\d{'.$max_int_length.',})/', ': "$1"', $input);
275
            $obj = json_decode($json_without_bigints);
276
        }
277
278
        if (function_exists('json_last_error') && $errno = json_last_error()) {
279
            static::handleJsonError($errno);
280
        } elseif ($obj === null && $input !== 'null') {
281
            throw new DomainException('Null result with non-null input');
282
        }
283
        return $obj;
284
    }
285
286
    /**
287
     * Encode a PHP object into a JSON string.
288
     *
289
     * @param object|array $input A PHP object or array
290
     *
291
     * @return string JSON representation of the PHP object or array
292
     *
293
     * @throws DomainException Provided object could not be encoded to valid JSON
294
     */
295
    public static function jsonEncode($input)
296
    {
297
        $json = json_encode($input);
298
        if (function_exists('json_last_error') && $errno = json_last_error()) {
299
            static::handleJsonError($errno);
300
        } elseif ($json === 'null' && $input !== null) {
301
            throw new DomainException('Null result with non-null input');
302
        }
303
        return $json;
304
    }
305
306
    /**
307
     * Decode a string with URL-safe Base64.
308
     *
309
     * @param string $input A Base64 encoded string
310
     *
311
     * @return string A decoded string
312
     */
313
    public static function urlsafeB64Decode($input)
314
    {
315
        $remainder = strlen($input) % 4;
316
        if ($remainder) {
317
            $padlen = 4 - $remainder;
318
            $input .= str_repeat('=', $padlen);
319
        }
320
        return base64_decode(strtr($input, '-_', '+/'));
321
    }
322
323
    /**
324
     * Encode a string with URL-safe Base64.
325
     *
326
     * @param string $input The string you want encoded
327
     *
328
     * @return string The base64 encode of what you passed in
329
     */
330
    public static function urlsafeB64Encode($input)
331
    {
332
        return str_replace('=', '', strtr(base64_encode($input), '+/', '-_'));
333
    }
334
335
    /**
336
     * Helper method to create a JSON error.
337
     *
338
     * @param int $errno An error number from json_last_error()
339
     *
340
     * @return void
341
     */
342
    private static function handleJsonError($errno)
343
    {
344
        $messages = array(
345
            JSON_ERROR_DEPTH => 'Maximum stack depth exceeded',
346
            JSON_ERROR_CTRL_CHAR => 'Unexpected control character found',
347
            JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON'
348
        );
349
        throw new DomainException(
350
            isset($messages[$errno])
351
            ? $messages[$errno]
352
            : 'Unknown JSON error: ' . $errno
353
        );
354
    }
355
356
    /**
357
     * Get the number of bytes in cryptographic strings.
358
     *
359
     * @param string
360
     *
361
     * @return int
362
     */
363
    private static function safeStrlen($str)
364
    {
365
        if (function_exists('mb_strlen')) {
366
            return mb_strlen($str, '8bit');
367
        }
368
        return strlen($str);
369
    }
370
}
371