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<?php |
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|
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/* |
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* Copyright 2008 Google Inc. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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|
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namespace Google\AccessToken; |
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|
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use DateTime; |
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use DomainException; |
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use Exception; |
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use ExpiredException; |
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use Firebase\JWT\ExpiredException as ExpiredExceptionV3; |
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use Firebase\JWT\JWT; |
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use Firebase\JWT\Key; |
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use Firebase\JWT\SignatureInvalidException; |
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use Google\Auth\Cache\MemoryCacheItemPool; |
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use Google\Exception as GoogleException; |
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use GuzzleHttp\Client; |
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use GuzzleHttp\ClientInterface; |
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use InvalidArgumentException; |
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use LogicException; |
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use phpseclib3\Crypt\AES; |
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use phpseclib3\Crypt\PublicKeyLoader; |
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use phpseclib3\Math\BigInteger; |
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use Psr\Cache\CacheItemPoolInterface; |
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|
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/** |
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* Wrapper around Google Access Tokens which provides convenience functions |
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* |
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*/ |
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class Verify |
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{ |
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const FEDERATED_SIGNON_CERT_URL = 'https://www.googleapis.com/oauth2/v3/certs'; |
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const OAUTH2_ISSUER = 'accounts.google.com'; |
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const OAUTH2_ISSUER_HTTPS = 'https://accounts.google.com'; |
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|
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/** |
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* @var ClientInterface The http client |
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*/ |
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private $http; |
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|
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/** |
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* @var CacheItemPoolInterface cache class |
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*/ |
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private $cache; |
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|
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/** |
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* @var \Firebase\JWT\JWT |
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*/ |
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public $jwt; |
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|
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/** |
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* Instantiates the class, but does not initiate the login flow, leaving it |
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* to the discretion of the caller. |
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*/ |
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public function __construct( |
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?ClientInterface $http = null, |
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?CacheItemPoolInterface $cache = null, |
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?JWT $jwt = null |
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) { |
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if (null === $http) { |
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$http = new Client(); |
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} |
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|
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if (null === $cache) { |
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$cache = new MemoryCacheItemPool(); |
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} |
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|
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$this->http = $http; |
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$this->cache = $cache; |
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$this->jwt = $jwt ?: $this->getJwtService(); |
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} |
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|
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/** |
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* Verifies an id token and returns the authenticated apiLoginTicket. |
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* Throws an exception if the id token is not valid. |
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* The audience parameter can be used to control which id tokens are |
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* accepted. By default, the id token must have been issued to this OAuth2 client. |
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* |
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* @param string $idToken the ID token in JWT format |
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* @param string $audience Optional. The audience to verify against JWt "aud" |
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* @return array|false the token payload, if successful |
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*/ |
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public function verifyIdToken($idToken, $audience = null) |
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{ |
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if (empty($idToken)) { |
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throw new LogicException('id_token cannot be null'); |
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} |
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|
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// set phpseclib constants if applicable |
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$this->setPhpsecConstants(); |
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|
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// Check signature |
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$certs = $this->getFederatedSignOnCerts(); |
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foreach ($certs as $cert) { |
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try { |
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$args = [$idToken]; |
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$publicKey = $this->getPublicKey($cert); |
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if (class_exists(Key::class)) { |
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$args[] = new Key($publicKey, 'RS256'); |
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} else { |
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$args[] = $publicKey; |
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$args[] = ['RS256']; |
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} |
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$payload = \call_user_func_array([$this->jwt, 'decode'], $args); |
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|
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if (property_exists($payload, 'aud')) { |
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if ($audience && $payload->aud != $audience) { |
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return false; |
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} |
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} |
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|
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// support HTTP and HTTPS issuers |
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// @see https://developers.google.com/identity/sign-in/web/backend-auth |
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$issuers = [self::OAUTH2_ISSUER, self::OAUTH2_ISSUER_HTTPS]; |
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if (!isset($payload->iss) || !in_array($payload->iss, $issuers)) { |
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return false; |
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} |
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|
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return (array)$payload; |
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} catch (ExpiredException $e) { // @phpstan-ignore-line |
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return false; |
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} catch (ExpiredExceptionV3 $e) { |
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return false; |
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} catch (SignatureInvalidException $e) { |
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// continue |
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} catch (DomainException $e) { |
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// continue |
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} |
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} |
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|
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return false; |
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} |
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|
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private function getCache() |
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{ |
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return $this->cache; |
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} |
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|
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/** |
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* Retrieve and cache a certificates file. |
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* |
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* @param string $url location |
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* @return array certificates |
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* @throws \Google\Exception |
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*/ |
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private function retrieveCertsFromLocation($url) |
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{ |
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// If we're retrieving a local file, just grab it. |
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if (0 !== strpos($url, 'http')) { |
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if (!$file = file_get_contents($url)) { |
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throw new GoogleException( |
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"Failed to retrieve verification certificates: '". |
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$url."'." |
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); |
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} |
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return json_decode($file, true); |
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} |
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|
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// @phpstan-ignore-next-line |
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$response = $this->http->get($url); |
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|
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if ($response->getStatusCode() == 200) { |
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return json_decode((string)$response->getBody(), true); |
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} |
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throw new GoogleException( |
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sprintf( |
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'Failed to retrieve verification certificates: "%s".', |
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$response->getBody()->getContents() |
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), |
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$response->getStatusCode() |
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); |
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} |
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|
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// Gets federated sign-on certificates to use for verifying identity tokens. |
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// Returns certs as array structure, where keys are key ids, and values |
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// are PEM encoded certificates. |
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private function getFederatedSignOnCerts() |
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{ |
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$certs = null; |
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if ($cache = $this->getCache()) { |
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$cacheItem = $cache->getItem('federated_signon_certs_v3'); |
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$certs = $cacheItem->get(); |
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} |
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|
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|
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if (!$certs) { |
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$certs = $this->retrieveCertsFromLocation( |
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self::FEDERATED_SIGNON_CERT_URL |
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); |
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|
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if ($cache) { |
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$cacheItem->expiresAt(new DateTime('+1 hour')); |
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$cacheItem->set($certs); |
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$cache->save($cacheItem); |
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} |
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} |
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|
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if (!isset($certs['keys'])) { |
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throw new InvalidArgumentException( |
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'federated sign-on certs expects "keys" to be set' |
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); |
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} |
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|
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return $certs['keys']; |
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} |
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|
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private function getJwtService() |
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{ |
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$jwt = new JWT(); |
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if ($jwt::$leeway < 1) { |
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// Ensures JWT leeway is at least 1 |
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// @see https://github.com/google/google-api-php-client/issues/827 |
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$jwt::$leeway = 1; |
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} |
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return $jwt; |
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} |
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|
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private function getPublicKey($cert) |
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{ |
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$modulus = new BigInteger($this->jwt->urlsafeB64Decode($cert['n']), 256); |
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$exponent = new BigInteger($this->jwt->urlsafeB64Decode($cert['e']), 256); |
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$component = ['n' => $modulus, 'e' => $exponent]; |
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|
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$loader = PublicKeyLoader::load($component); |
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|
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return $loader->toString('PKCS8'); |
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} |
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|
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/** |
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* phpseclib calls "phpinfo" by default, which requires special |
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* whitelisting in the AppEngine VM environment. This function |
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* sets constants to bypass the need for phpseclib to check phpinfo |
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* |
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* @see phpseclib/Math/BigInteger |
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* @see https://github.com/GoogleCloudPlatform/getting-started-php/issues/85 |
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*/ |
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private function setPhpsecConstants() |
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{ |
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if (filter_var(getenv('GAE_VM'), FILTER_VALIDATE_BOOLEAN)) { |
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if (!defined('MATH_BIGINTEGER_OPENSSL_ENABLED')) { |
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define('MATH_BIGINTEGER_OPENSSL_ENABLED', true); |
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} |
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if (!defined('CRYPT_RSA_MODE')) { |
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define('CRYPT_RSA_MODE', AES::ENGINE_OPENSSL); |
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} |
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} |
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} |
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} |
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|
