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extensions/blocks/premium-content/_inc/subscription-service/class-jwt.php
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| 1 | +<?php | |
| 2 | +/** | |
| 3 | + * JSON Web Token implementation, based on this spec: | |
| 4 | + * https://tools.ietf.org/html/rfc7519 | |
| 5 | + * | |
| 6 | + * @package Automattic\Jetpack\Extensions\Premium_Content | |
| 7 | + */ | |
| 8 | + | |
| 9 | +namespace Automattic\Jetpack\Extensions\Premium_Content; | |
| 10 | + | |
| 11 | +use DateTime; | |
| 12 | +use DomainException; | |
| 13 | +use InvalidArgumentException; | |
| 14 | +use UnexpectedValueException; | |
| 15 | + | |
| 16 | +if ( ! defined( 'ABSPATH' ) ) { | |
| 17 | + exit( 0 ); | |
| 18 | +} | |
| 19 | + | |
| 20 | +/** | |
| 21 | + * JSON Web Token implementation, based on this spec: | |
| 22 | + * https://tools.ietf.org/html/rfc7519 | |
| 23 | + * | |
| 24 | + * PHP version 5 | |
| 25 | + * | |
| 26 | + * @category Authentication | |
| 27 | + * @package Authentication_JWT | |
| 28 | + * @author Neuman Vong <[email protected]> | |
| 29 | + * @author Anant Narayanan <[email protected]> | |
| 30 | + * @license http://opensource.org/licenses/BSD-3-Clause 3-clause BSD | |
| 31 | + * @link https://github.com/firebase/php-jwt | |
| 32 | + */ | |
| 33 | +class JWT { | |
| 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 $leeway The leeway value. | |
| 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 | + * | |
| 47 | + * Will default to PHP time() value if null. | |
| 48 | + * | |
| 49 | + * @var string $timestamp The timestamp. | |
| 50 | + */ | |
| 51 | + public static $timestamp = null; | |
| 52 | + | |
| 53 | + /** | |
| 54 | + * Supported algorithms. | |
| 55 | + * | |
| 56 | + * @var array $supported_algs Supported algorithms. | |
| 57 | + */ | |
| 58 | + public static $supported_algs = array( | |
| 59 | + 'HS256' => array( 'hash_hmac', 'SHA256' ), | |
| 60 | + 'HS512' => array( 'hash_hmac', 'SHA512' ), | |
| 61 | + 'HS384' => array( 'hash_hmac', 'SHA384' ), | |
| 62 | + 'RS256' => array( 'openssl', 'SHA256' ), | |
| 63 | + 'RS384' => array( 'openssl', 'SHA384' ), | |
| 64 | + 'RS512' => array( 'openssl', 'SHA512' ), | |
| 65 | + ); | |
| 66 | + | |
| 67 | + /** | |
| 68 | + * Decodes a JWT string into a PHP object. | |
| 69 | + * | |
| 70 | + * @param string $jwt The JWT. | |
| 71 | + * @param string|array $key The key, or map of keys. | |
| 72 | + * If the algorithm used is asymmetric, this is the public key. | |
| 73 | + * @param array $allowed_algs List of supported verification algorithms. | |
| 74 | + * Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'. | |
| 75 | + * | |
| 76 | + * @return object The JWT's payload as a PHP object | |
| 77 | + * | |
| 78 | + * @throws UnexpectedValueException Provided JWT was invalid. | |
| 79 | + * @throws SignatureInvalidException Provided JWT was invalid because the signature verification failed. | |
| 80 | + * @throws InvalidArgumentException Provided JWT is trying to be used before it's eligible as defined by 'nbf'. | |
| 81 | + * @throws BeforeValidException Provided JWT is trying to be used before it's been created as defined by 'iat'. | |
| 82 | + * @throws ExpiredException Provided JWT has since expired, as defined by the 'exp' claim. | |
| 83 | + * | |
| 84 | + * @uses json_decode | |
| 85 | + * @uses urlsafe_b64_decode | |
| 86 | + */ | |
| 87 | + public static function decode( $jwt, $key, array $allowed_algs = array() ) { | |
| 88 | + $timestamp = static::$timestamp === null ? time() : static::$timestamp; | |
| 89 | + | |
| 90 | + if ( empty( $key ) ) { | |
| 91 | + throw new InvalidArgumentException( 'Key may not be empty' ); | |
| 92 | + } | |
| 93 | + | |
| 94 | + $tks = explode( '.', $jwt ); | |
| 95 | + if ( count( $tks ) !== 3 ) { | |
| 96 | + throw new UnexpectedValueException( 'Wrong number of segments' ); | |
| 97 | + } | |
| 98 | + | |
| 99 | + list( $headb64, $bodyb64, $cryptob64 ) = $tks; | |
| 100 | + | |
| 101 | + $header = static::json_decode( static::urlsafe_b64_decode( $headb64 ) ); | |
| 102 | + if ( null === $header ) { | |
| 103 | + throw new UnexpectedValueException( 'Invalid header encoding' ); | |
| 104 | + } | |
| 105 | + | |
| 106 | + $payload = static::json_decode( static::urlsafe_b64_decode( $bodyb64 ) ); | |
| 107 | + if ( null === $payload ) { | |
| 108 | + throw new UnexpectedValueException( 'Invalid claims encoding' ); | |
| 109 | + } | |
| 110 | + | |
| 111 | + $sig = static::urlsafe_b64_decode( $cryptob64 ); | |
| 112 | + if ( false === $sig ) { | |
| 113 | + throw new UnexpectedValueException( 'Invalid signature encoding' ); | |
| 114 | + } | |
| 115 | + | |
| 116 | + if ( empty( $header->alg ) ) { | |
| 117 | + throw new UnexpectedValueException( 'Empty algorithm' ); | |
| 118 | + } | |
| 119 | + | |
| 120 | + if ( empty( static::$supported_algs[ $header->alg ] ) ) { | |
| 121 | + throw new UnexpectedValueException( 'Algorithm not supported' ); | |
| 122 | + } | |
| 123 | + | |
| 124 | + if ( ! in_array( $header->alg, $allowed_algs, true ) ) { | |
| 125 | + throw new UnexpectedValueException( 'Algorithm not allowed' ); | |
| 126 | + } | |
| 127 | + | |
| 128 | + if ( is_array( $key ) || $key instanceof \ArrayAccess ) { | |
| 129 | + if ( isset( $header->kid ) ) { | |
| 130 | + if ( ! isset( $key[ $header->kid ] ) ) { | |
| 131 | + throw new UnexpectedValueException( '"kid" invalid, unable to lookup correct key' ); | |
| 132 | + } | |
| 133 | + $key = $key[ $header->kid ]; | |
| 134 | + } else { | |
| 135 | + throw new UnexpectedValueException( '"kid" empty, unable to lookup correct key' ); | |
| 136 | + } | |
| 137 | + } | |
| 138 | + | |
| 139 | + // Check the signature. | |
| 140 | + if ( ! static::verify( "$headb64.$bodyb64", $sig, $key, $header->alg ) ) { | |
| 141 | + throw new SignatureInvalidException( 'Signature verification failed' ); | |
| 142 | + } | |
| 143 | + | |
| 144 | + // Check if the nbf if it is defined. This is the time that the | |
| 145 | + // token can actually be used. If it's not yet that time, abort. | |
| 146 | + if ( isset( $payload->nbf ) && $payload->nbf > ( $timestamp + static::$leeway ) ) { | |
| 147 | + throw new BeforeValidException( | |
| 148 | + 'Cannot handle token prior to ' . gmdate( DateTime::ISO8601, $payload->nbf ) | |
| 149 | + ); | |
| 150 | + } | |
| 151 | + | |
| 152 | + // Check that this token has been created before 'now'. This prevents | |
| 153 | + // using tokens that have been created for later use (and haven't | |
| 154 | + // correctly used the nbf claim). | |
| 155 | + if ( isset( $payload->iat ) && $payload->iat > ( $timestamp + static::$leeway ) ) { | |
| 156 | + throw new BeforeValidException( | |
| 157 | + 'Cannot handle token prior to ' . gmdate( DateTime::ISO8601, $payload->iat ) | |
| 158 | + ); | |
| 159 | + } | |
| 160 | + | |
| 161 | + // Check if this token has expired. | |
| 162 | + if ( isset( $payload->exp ) && ( $timestamp - static::$leeway ) >= $payload->exp ) { | |
| 163 | + throw new ExpiredException( 'Expired token' ); | |
| 164 | + } | |
| 165 | + | |
| 166 | + return $payload; | |
| 167 | + } | |
| 168 | + | |
| 169 | + /** | |
| 170 | + * Converts and signs a PHP object or array into a JWT string. | |
| 171 | + * | |
| 172 | + * @param object|array $payload PHP object or array. | |
| 173 | + * @param string $key The secret key. | |
| 174 | + * If the algorithm used is asymmetric, this is the private key. | |
| 175 | + * @param string $alg The signing algorithm. | |
| 176 | + * Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'. | |
| 177 | + * @param mixed $key_id The key ID. | |
| 178 | + * @param array $head An array with header elements to attach. | |
| 179 | + * | |
| 180 | + * @return string A signed JWT | |
| 181 | + * | |
| 182 | + * @uses json_encode | |
| 183 | + * @uses urlsafe_b64_decode | |
| 184 | + */ | |
| 185 | + public static function encode( $payload, $key, $alg = 'HS256', $key_id = null, $head = null ) { | |
| 186 | + $header = array( | |
| 187 | + 'typ' => 'JWT', | |
| 188 | + 'alg' => $alg, | |
| 189 | + ); | |
| 190 | + | |
| 191 | + if ( null !== $key_id ) { | |
| 192 | + $header['kid'] = $key_id; | |
| 193 | + } | |
| 194 | + | |
| 195 | + if ( isset( $head ) && is_array( $head ) ) { | |
| 196 | + $header = array_merge( $head, $header ); | |
| 197 | + } | |
| 198 | + | |
| 199 | + $segments = array(); | |
| 200 | + $segments[] = static::urlsafe_b64_encode( static::json_encode( $header ) ); | |
| 201 | + $segments[] = static::urlsafe_b64_encode( static::json_encode( $payload ) ); | |
| 202 | + $signing_input = implode( '.', $segments ); | |
| 203 | + | |
| 204 | + $signature = static::sign( $signing_input, $key, $alg ); | |
| 205 | + $segments[] = static::urlsafe_b64_encode( $signature ); | |
| 206 | + | |
| 207 | + return implode( '.', $segments ); | |
| 208 | + } | |
| 209 | + | |
| 210 | + /** | |
| 211 | + * Sign a string with a given key and algorithm. | |
| 212 | + * | |
| 213 | + * @param string $msg The message to sign. | |
| 214 | + * @param string|resource $key The secret key. | |
| 215 | + * @param string $alg The signing algorithm. | |
| 216 | + * Supported algorithms are 'HS256', 'HS384', 'HS512' and 'RS256'. | |
| 217 | + * | |
| 218 | + * @return string An encrypted message | |
| 219 | + * | |
| 220 | + * @throws DomainException Unsupported algorithm was specified. | |
| 221 | + */ | |
| 222 | + public static function sign( $msg, $key, $alg = 'HS256' ) { | |
| 223 | + if ( empty( static::$supported_algs[ $alg ] ) ) { | |
| 224 | + throw new DomainException( 'Algorithm not supported' ); | |
| 225 | + } | |
| 226 | + list($function, $algorithm) = static::$supported_algs[ $alg ]; | |
| 227 | + switch ( $function ) { | |
| 228 | + case 'hash_hmac': | |
| 229 | + return hash_hmac( $algorithm, $msg, $key, true ); | |
| 230 | + case 'openssl': | |
| 231 | + $signature = ''; | |
| 232 | + $success = openssl_sign( $msg, $signature, $key, $algorithm ); | |
| 233 | + if ( ! $success ) { | |
| 234 | + throw new DomainException( 'OpenSSL unable to sign data' ); | |
| 235 | + } else { | |
| 236 | + return $signature; | |
| 237 | + } | |
| 238 | + } | |
| 239 | + } | |
| 240 | + | |
| 241 | + /** | |
| 242 | + * Verify a signature with the message, key and method. Not all methods | |
| 243 | + * are symmetric, so we must have a separate verify and sign method. | |
| 244 | + * | |
| 245 | + * @param string $msg The original message (header and body). | |
| 246 | + * @param string $signature The original signature. | |
| 247 | + * @param string|resource $key For HS*, a string key works. for RS*, must be a resource of an openssl public key. | |
| 248 | + * @param string $alg The algorithm. | |
| 249 | + * | |
| 250 | + * @return bool | |
| 251 | + * | |
| 252 | + * @throws DomainException Invalid Algorithm or OpenSSL failure. | |
| 253 | + */ | |
| 254 | + private static function verify( $msg, $signature, $key, $alg ) { | |
| 255 | + if ( empty( static::$supported_algs[ $alg ] ) ) { | |
| 256 | + throw new DomainException( 'Algorithm not supported' ); | |
| 257 | + } | |
| 258 | + | |
| 259 | + list($function, $algorithm) = static::$supported_algs[ $alg ]; | |
| 260 | + switch ( $function ) { | |
| 261 | + case 'openssl': | |
| 262 | + $success = openssl_verify( $msg, $signature, $key, $algorithm ); | |
| 263 | + | |
| 264 | + if ( 1 === $success ) { | |
| 265 | + return true; | |
| 266 | + } elseif ( 0 === $success ) { | |
| 267 | + return false; | |
| 268 | + } | |
| 269 | + | |
| 270 | + // returns 1 on success, 0 on failure, -1 on error. | |
| 271 | + throw new DomainException( | |
| 272 | + 'OpenSSL error: ' . openssl_error_string() | |
| 273 | + ); | |
| 274 | + case 'hash_hmac': | |
| 275 | + default: | |
| 276 | + $hash = hash_hmac( $algorithm, $msg, $key, true ); | |
| 277 | + | |
| 278 | + if ( function_exists( 'hash_equals' ) ) { | |
| 279 | + return hash_equals( $signature, $hash ); | |
| 280 | + } | |
| 281 | + | |
| 282 | + $len = min( static::safe_strlen( $signature ), static::safe_strlen( $hash ) ); | |
| 283 | + | |
| 284 | + $status = 0; | |
| 285 | + | |
| 286 | + for ( $i = 0; $i < $len; $i++ ) { | |
| 287 | + $status |= ( ord( $signature[ $i ] ) ^ ord( $hash[ $i ] ) ); | |
| 288 | + } | |
| 289 | + | |
| 290 | + $status |= ( static::safe_strlen( $signature ) ^ static::safe_strlen( $hash ) ); | |
| 291 | + | |
| 292 | + return ( 0 === $status ); | |
| 293 | + } | |
| 294 | + } | |
| 295 | + | |
| 296 | + /** | |
| 297 | + * Decode a JSON string into a PHP object. | |
| 298 | + * | |
| 299 | + * @param string $input JSON string. | |
| 300 | + * | |
| 301 | + * @return object Object representation of JSON string | |
| 302 | + * | |
| 303 | + * @throws DomainException Provided string was invalid JSON. | |
| 304 | + */ | |
| 305 | + public static function json_decode( $input ) { | |
| 306 | + $obj = json_decode( $input, false, 512, JSON_BIGINT_AS_STRING ); | |
| 307 | + $errno = json_last_error(); | |
| 308 | + | |
| 309 | + if ( $errno ) { | |
| 310 | + static::handle_json_error( $errno ); | |
| 311 | + } elseif ( null === $obj && 'null' !== $input ) { | |
| 312 | + throw new DomainException( 'Null result with non-null input' ); | |
| 313 | + } | |
| 314 | + return $obj; | |
| 315 | + } | |
| 316 | + | |
| 317 | + /** | |
| 318 | + * Encode a PHP object into a JSON string. | |
| 319 | + * | |
| 320 | + * @param object|array $input A PHP object or array. | |
| 321 | + * | |
| 322 | + * @return string JSON representation of the PHP object or array. | |
| 323 | + * | |
| 324 | + * @throws DomainException Provided object could not be encoded to valid JSON. | |
| 325 | + */ | |
| 326 | + public static function json_encode( $input ) { | |
| 327 | + $json = wp_json_encode( $input, JSON_UNESCAPED_SLASHES ); | |
| 328 | + $errno = json_last_error(); | |
| 329 | + | |
| 330 | + if ( $errno ) { | |
| 331 | + static::handle_json_error( $errno ); | |
| 332 | + } elseif ( 'null' === $json && null !== $input ) { | |
| 333 | + throw new DomainException( 'Null result with non-null input' ); | |
| 334 | + } | |
| 335 | + return $json; | |
| 336 | + } | |
| 337 | + | |
| 338 | + /** | |
| 339 | + * Decode a string with URL-safe Base64. | |
| 340 | + * | |
| 341 | + * @param string $input A Base64 encoded string. | |
| 342 | + * | |
| 343 | + * @return string A decoded string | |
| 344 | + */ | |
| 345 | + public static function urlsafe_b64_decode( $input ) { | |
| 346 | + $remainder = strlen( $input ) % 4; | |
| 347 | + if ( $remainder ) { | |
| 348 | + $padlen = 4 - $remainder; | |
| 349 | + $input .= str_repeat( '=', $padlen ); | |
| 350 | + } | |
| 351 | + // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_decode | |
| 352 | + return base64_decode( strtr( $input, '-_', '+/' ) ); | |
| 353 | + } | |
| 354 | + | |
| 355 | + /** | |
| 356 | + * Encode a string with URL-safe Base64. | |
| 357 | + * | |
| 358 | + * @param string $input The string you want encoded. | |
| 359 | + * | |
| 360 | + * @return string The base64 encode of what you passed in | |
| 361 | + */ | |
| 362 | + public static function urlsafe_b64_encode( $input ) { | |
| 363 | + // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode | |
| 364 | + return str_replace( '=', '', strtr( base64_encode( $input ), '+/', '-_' ) ); | |
| 365 | + } | |
| 366 | + | |
| 367 | + /** | |
| 368 | + * Helper method to create a JSON error. | |
| 369 | + * | |
| 370 | + * @param int $errno An error number from json_last_error(). | |
| 371 | + * @throws DomainException . | |
| 372 | + * | |
| 373 | + * @return never | |
| 374 | + */ | |
| 375 | + private static function handle_json_error( $errno ) { | |
| 376 | + $messages = array( | |
| 377 | + JSON_ERROR_DEPTH => 'Maximum stack depth exceeded', | |
| 378 | + JSON_ERROR_STATE_MISMATCH => 'Invalid or malformed JSON', | |
| 379 | + JSON_ERROR_CTRL_CHAR => 'Unexpected control character found', | |
| 380 | + JSON_ERROR_SYNTAX => 'Syntax error, malformed JSON', | |
| 381 | + JSON_ERROR_UTF8 => 'Malformed UTF-8 characters', | |
| 382 | + ); | |
| 383 | + throw new DomainException( | |
| 384 | + $messages[ $errno ] ?? 'Unknown JSON error: ' . $errno | |
| 385 | + ); | |
| 386 | + } | |
| 387 | + | |
| 388 | + /** | |
| 389 | + * Get the number of bytes in cryptographic strings. | |
| 390 | + * | |
| 391 | + * @param string $str . | |
| 392 | + * | |
| 393 | + * @return int | |
| 394 | + */ | |
| 395 | + private static function safe_strlen( $str ) { | |
| 396 | + if ( function_exists( 'mb_strlen' ) ) { | |
| 397 | + return mb_strlen( $str, '8bit' ); | |
| 398 | + } | |
| 399 | + return strlen( $str ); | |
| 400 | + } | |
| 401 | +} | |
| 402 | + | |
| 403 | +// phpcs:disable | |
| 404 | +if ( ! class_exists( 'SignatureInvalidException' ) ) { | |
| 405 | + /** | |
| 406 | + * SignatureInvalidException | |
| 407 | + * | |
| 408 | + * @package Automattic\Jetpack\Extensions\Premium_Content | |
| 409 | + */ | |
| 410 | + class SignatureInvalidException extends \UnexpectedValueException { } | |
| 411 | +} | |
| 412 | +if ( ! class_exists( 'ExpiredException' ) ) { | |
| 413 | + /** | |
| 414 | + * ExpiredException | |
| 415 | + * | |
| 416 | + * @package Automattic\Jetpack\Extensions\Premium_Content | |
| 417 | + */ | |
| 418 | + class ExpiredException extends \UnexpectedValueException { } | |
| 419 | +} | |
| 420 | +if ( ! class_exists( 'BeforeValidException' ) ) { | |
| 421 | + /** | |
| 422 | + * BeforeValidException | |
| 423 | + * | |
| 424 | + * @package Automattic\Jetpack\Extensions\Premium_Content | |
| 425 | + */ | |
| 426 | + class BeforeValidException extends \UnexpectedValueException { } | |
| 427 | +} | |
| 428 | +// phpcs:enable | |