<?php
/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// phpcs:disable WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Error message to be escaped when caught and printed.
if (!defined('ABSPATH')) die('No direct access allowed');
if (!class_exists('UDP_Google_Client')) {
require_once dirname(__FILE__) . '/../autoload.php';
}
/**
* Authentication class that deals with the OAuth 2 web-server authentication flow
*
*/
class Google_Auth_OAuth2 extends Google_Auth_Abstract
{
const OAUTH2_REVOKE_URI = 'https://accounts.google.com/o/oauth2/revoke';
const OAUTH2_TOKEN_URI = 'https://accounts.google.com/o/oauth2/token';
const OAUTH2_AUTH_URL = 'https://accounts.google.com/o/oauth2/auth';
const CLOCK_SKEW_SECS = 300; // five minutes in seconds
const AUTH_TOKEN_LIFETIME_SECS = 300; // five minutes in seconds
const MAX_TOKEN_LIFETIME_SECS = 86400; // one day in seconds
const OAUTH2_ISSUER = 'accounts.google.com';
/** @var Google_Auth_AssertionCredentials $assertionCredentials */
private $assertionCredentials;
/**
* @var string The state parameters for CSRF and other forgery protection.
*/
private $state;
/**
* @var array The token bundle.
*/
private $token = array();
/**
* @var UDP_Google_Client the base client
*/
private $client;
/**
* Instantiates the class, but does not initiate the login flow, leaving it
* to the discretion of the caller.
*/
public function __construct(UDP_Google_Client $client)
{
$this->client = $client;
}
/**
* Perform an authenticated / signed apiHttpRequest.
* This function takes the apiHttpRequest, calls apiAuth->sign on it
* (which can modify the request in what ever way fits the auth mechanism)
* and then calls apiCurlIO::makeRequest on the signed request
*
* @param Google_Http_Request $request
* @return Google_Http_Request The resulting HTTP response including the
* responseHttpCode, responseHeaders and responseBody.
*/
public function authenticatedRequest(UDP_Google_Http_Request $request)
{
$request = $this->sign($request);
return $this->client->getIo()->makeRequest($request);
}
/**
* @param string $code
* @throws Google_Auth_Exception
* @return string
*/
public function authenticate($code)
{
if (strlen($code) == 0) {
throw new Google_Auth_Exception("Invalid code");
}
// We got here from the redirect from a successful authorization grant,
// fetch the access token
$request = new UDP_Google_Http_Request(
self::OAUTH2_TOKEN_URI,
'POST',
array(),
array(
'code' => $code,
'grant_type' => 'authorization_code',
'redirect_uri' => $this->client->getClassConfig($this, 'redirect_uri'),
'client_id' => $this->client->getClassConfig($this, 'client_id'),
'client_secret' => $this->client->getClassConfig($this, 'client_secret')
)
);
$request->disableGzip();
$response = $this->client->getIo()->makeRequest($request);
if ($response->getResponseHttpCode() == 200) {
$this->setAccessToken($response->getResponseBody());
$this->token['created'] = time();
return $this->getAccessToken();
} else {
$decodedResponse = json_decode($response->getResponseBody(), true);
if ($decodedResponse != null && $decodedResponse['error']) {
$errorText = $decodedResponse['error'];
if (isset($decodedResponse['error_description'])) {
$errorText .= ": " . $decodedResponse['error_description'];
}
}
throw new Google_Auth_Exception(
sprintf(
"Error fetching OAuth2 access token, message: '%s'",
$errorText
),
$response->getResponseHttpCode()
);
}
}
/**
* Create a URL to obtain user authorization.
* The authorization endpoint allows the user to first
* authenticate, and then grant/deny the access request.
* @param string $scope The scope is expressed as a list of space-delimited strings.
* @return string
*/
public function createAuthUrl($scope)
{
$params = array(
'response_type' => 'code',
'redirect_uri' => $this->client->getClassConfig($this, 'redirect_uri'),
'client_id' => $this->client->getClassConfig($this, 'client_id'),
'scope' => $scope,
'access_type' => $this->client->getClassConfig($this, 'access_type'),
);
// Prefer prompt to approval prompt.
if ($this->client->getClassConfig($this, 'prompt')) {
$params = $this->maybeAddParam($params, 'prompt');
} else {
$params = $this->maybeAddParam($params, 'approval_prompt');
}
$params = $this->maybeAddParam($params, 'login_hint');
$params = $this->maybeAddParam($params, 'hd');
$params = $this->maybeAddParam($params, 'openid.realm');
$params = $this->maybeAddParam($params, 'include_granted_scopes');
// If the list of scopes contains plus.login, add request_visible_actions
// to auth URL.
$rva = $this->client->getClassConfig($this, 'request_visible_actions');
if (strpos($scope, 'plus.login') && strlen($rva) > 0) {
$params['request_visible_actions'] = $rva;
}
if (isset($this->state)) {
$params['state'] = $this->state;
}
return self::OAUTH2_AUTH_URL . "?" . http_build_query($params, '', '&');
}
/**
* @param string $token
* @throws Google_Auth_Exception
*/
public function setAccessToken($token)
{
$token = json_decode($token, true);
if ($token == null) {
throw new Google_Auth_Exception('Could not json decode the token');
}
if (! isset($token['access_token'])) {
throw new Google_Auth_Exception("Invalid token format");
}
$this->token = $token;
}
public function getAccessToken()
{
return json_encode($this->token);
}
public function getRefreshToken()
{
if (array_key_exists('refresh_token', $this->token)) {
return $this->token['refresh_token'];
} else {
return null;
}
}
public function setState($state)
{
$this->state = $state;
}
public function setAssertionCredentials(Google_Auth_AssertionCredentials $creds)
{
$this->assertionCredentials = $creds;
}
/**
* Include an accessToken in a given apiHttpRequest.
* @param Google_Http_Request $request
* @return Google_Http_Request
* @throws Google_Auth_Exception
*/
public function sign(UDP_Google_Http_Request $request)
{
// add the developer key to the request before signing it
if ($this->client->getClassConfig($this, 'developer_key')) {
$request->setQueryParam('key', $this->client->getClassConfig($this, 'developer_key'));
}
// Cannot sign the request without an OAuth access token.
if (null == $this->token && null == $this->assertionCredentials) {
return $request;
}
// Check if the token is set to expire in the next 30 seconds
// (or has already expired).
if ($this->isAccessTokenExpired()) {
if ($this->assertionCredentials) {
$this->refreshTokenWithAssertion();
} else {
$this->client->getLogger()->debug('OAuth2 access token expired');
if (! array_key_exists('refresh_token', $this->token)) {
$error = "The OAuth 2.0 access token has expired,"
." and a refresh token is not available. Refresh tokens"
." are not returned for responses that were auto-approved.";
$this->client->getLogger()->error($error);
throw new Google_Auth_Exception($error);
}
$this->refreshToken($this->token['refresh_token']);
}
}
$this->client->getLogger()->debug('OAuth2 authentication');
// Add the OAuth2 header to the request
$request->setRequestHeaders(
array('Authorization' => 'Bearer ' . $this->token['access_token'])
);
return $request;
}
/**
* Fetches a fresh access token with the given refresh token.
* @param string $refreshToken
* @return void
*/
public function refreshToken($refreshToken)
{
$this->refreshTokenRequest(
array(
'client_id' => $this->client->getClassConfig($this, 'client_id'),
'client_secret' => $this->client->getClassConfig($this, 'client_secret'),
'refresh_token' => $refreshToken,
'grant_type' => 'refresh_token'
)
);
}
/**
* Fetches a fresh access token with a given assertion token.
* @param Google_Auth_AssertionCredentials $assertionCredentials optional.
* @return void
*/
public function refreshTokenWithAssertion($assertionCredentials = null)
{
if (!$assertionCredentials) {
$assertionCredentials = $this->assertionCredentials;
}
$cacheKey = $assertionCredentials->getCacheKey();
if ($cacheKey) {
// We can check whether we have a token available in the
// cache. If it is expired, we can retrieve a new one from
// the assertion.
$token = $this->client->getCache()->get($cacheKey);
if ($token) {
$this->setAccessToken($token);
}
if (!$this->isAccessTokenExpired()) {
return;
}
}
$this->client->getLogger()->debug('OAuth2 access token expired');
$this->refreshTokenRequest(
array(
'grant_type' => 'assertion',
'assertion_type' => $assertionCredentials->assertionType,
'assertion' => $assertionCredentials->generateAssertion(),
)
);
if ($cacheKey) {
// Attempt to cache the token.
$this->client->getCache()->set(
$cacheKey,
$this->getAccessToken()
);
}
}
private function refreshTokenRequest($params)
{
if (isset($params['assertion'])) {
$this->client->getLogger()->info(
'OAuth2 access token refresh with Signed JWT assertion grants.'
);
} else {
$this->client->getLogger()->info('OAuth2 access token refresh');
}
$http = new UDP_Google_Http_Request(
self::OAUTH2_TOKEN_URI,
'POST',
array(),
$params
);
$http->disableGzip();
$request = $this->client->getIo()->makeRequest($http);
$code = $request->getResponseHttpCode();
$body = $request->getResponseBody();
if (200 == $code) {
$token = json_decode($body, true);
if ($token == null) {
throw new Google_Auth_Exception("Could not json decode the access token");
}
if (! isset($token['access_token']) || ! isset($token['expires_in'])) {
throw new Google_Auth_Exception("Invalid token format");
}
if (isset($token['id_token'])) {
$this->token['id_token'] = $token['id_token'];
}
$this->token['access_token'] = $token['access_token'];
$this->token['expires_in'] = $token['expires_in'];
$this->token['created'] = time();
} else {
throw new Google_Auth_Exception("Error refreshing the OAuth2 token, message: '$body'", $code);
}
}
/**
* Revoke an OAuth2 access token or refresh token. This method will revoke the current access
* token, if a token isn't provided.
* @throws Google_Auth_Exception
* @param string|null $token The token (access token or a refresh token) that should be revoked.
* @return boolean Returns True if the revocation was successful, otherwise False.
*/
public function revokeToken($token = null)
{
if (!$token) {
if (!$this->token) {
// Not initialized, no token to actually revoke
return false;
} elseif (array_key_exists('refresh_token', $this->token)) {
$token = $this->token['refresh_token'];
} else {
$token = $this->token['access_token'];
}
}
$request = new UDP_Google_Http_Request(
self::OAUTH2_REVOKE_URI,
'POST',
array(),
"token=$token"
);
$request->disableGzip();
$response = $this->client->getIo()->makeRequest($request);
$code = $response->getResponseHttpCode();
if ($code == 200) {
$this->token = null;
return true;
}
return false;
}
/**
* Returns if the access_token is expired.
* @return bool Returns True if the access_token is expired.
*/
public function isAccessTokenExpired()
{
if (!$this->token || !isset($this->token['created'])) {
return true;
}
// If the token is set to expire in the next 30 seconds.
$expired = ($this->token['created']
+ ($this->token['expires_in'] - 30)) < time();
return $expired;
}
// Gets federated sign-on certificates to use for verifying identity tokens.
// Returns certs as array structure, where keys are key ids, and values
// are PEM encoded certificates.
private function getFederatedSignOnCerts()
{
return $this->retrieveCertsFromLocation(
$this->client->getClassConfig($this, 'federated_signon_certs_url')
);
}
/**
* Retrieve and cache a certificates file.
*
* @param $url string location
* @throws Google_Auth_Exception
* @return array certificates
*/
public function retrieveCertsFromLocation($url)
{
// If we're retrieving a local file, just grab it.
if ("http" != substr($url, 0, 4)) {
$file = file_get_contents($url);
if ($file) {
return json_decode($file, true);
} else {
throw new Google_Auth_Exception(
"Failed to retrieve verification certificates: '" .
$url . "'."
);
}
}
// This relies on makeRequest caching certificate responses.
$request = $this->client->getIo()->makeRequest(
new UDP_Google_Http_Request(
$url
)
);
if ($request->getResponseHttpCode() == 200) {
$certs = json_decode($request->getResponseBody(), true);
if ($certs) {
return $certs;
}
}
throw new Google_Auth_Exception(
"Failed to retrieve verification certificates: '" .
$request->getResponseBody() . "'.",
$request->getResponseHttpCode()
);
}
/**
* Verifies an id token and returns the authenticated apiLoginTicket.
* Throws an exception if the id token is not valid.
* The audience parameter can be used to control which id tokens are
* accepted. By default, the id token must have been issued to this OAuth2 client.
*
* @param $id_token
* @param $audience
* @return Google_Auth_LoginTicket
*/
public function verifyIdToken($id_token = null, $audience = null)
{
if (!$id_token) {
$id_token = $this->token['id_token'];
}
$certs = $this->getFederatedSignonCerts();
if (!$audience) {
$audience = $this->client->getClassConfig($this, 'client_id');
}
return $this->verifySignedJwtWithCerts($id_token, $certs, $audience, self::OAUTH2_ISSUER);
}
/**
* Verifies the id token, returns the verified token contents.
*
* @param $jwt string the token
* @param $certs array of certificates
* @param $required_audience string the expected consumer of the token
* @param [$issuer] the expected issues, defaults to Google
* @param [$max_expiry] the max lifetime of a token, defaults to MAX_TOKEN_LIFETIME_SECS
* @throws Google_Auth_Exception
* @return mixed token information if valid, false if not
*/
public function verifySignedJwtWithCerts(
$jwt,
$certs,
$required_audience,
$issuer = null,
$max_expiry = null
) {
if (!$max_expiry) {
// Set the maximum time we will accept a token for.
$max_expiry = self::MAX_TOKEN_LIFETIME_SECS;
}
$segments = explode(".", $jwt);
if (count($segments) != 3) {
throw new Google_Auth_Exception("Wrong number of segments in token: $jwt");
}
$signed = $segments[0] . "." . $segments[1];
$signature = Google_Utils::urlSafeB64Decode($segments[2]);
// Parse envelope.
$envelope = json_decode(Google_Utils::urlSafeB64Decode($segments[0]), true);
if (!$envelope) {
throw new Google_Auth_Exception("Can't parse token envelope: " . $segments[0]);
}
// Parse token
$json_body = Google_Utils::urlSafeB64Decode($segments[1]);
$payload = json_decode($json_body, true);
if (!$payload) {
throw new Google_Auth_Exception("Can't parse token payload: " . $segments[1]);
}
// Check signature
$verified = false;
foreach ($certs as $keyName => $pem) {
$public_key = new Google_Verifier_Pem($pem);
if ($public_key->verify($signed, $signature)) {
$verified = true;
break;
}
}
if (!$verified) {
throw new Google_Auth_Exception("Invalid token signature: $jwt");
}
// Check issued-at timestamp
$iat = 0;
if (array_key_exists("iat", $payload)) {
$iat = $payload["iat"];
}
if (!$iat) {
throw new Google_Auth_Exception("No issue time in token: $json_body");
}
$earliest = $iat - self::CLOCK_SKEW_SECS;
// Check expiration timestamp
$now = time();
$exp = 0;
if (array_key_exists("exp", $payload)) {
$exp = $payload["exp"];
}
if (!$exp) {
throw new Google_Auth_Exception("No expiration time in token: $json_body");
}
if ($exp >= $now + $max_expiry) {
throw new Google_Auth_Exception(
sprintf("Expiration time too far in future: %s", $json_body)
);
}
$latest = $exp + self::CLOCK_SKEW_SECS;
if ($now < $earliest) {
throw new Google_Auth_Exception(
sprintf(
"Token used too early, %s < %s: %s",
$now,
$earliest,
$json_body
)
);
}
if ($now > $latest) {
throw new Google_Auth_Exception(
sprintf(
"Token used too late, %s > %s: %s",
$now,
$latest,
$json_body
)
);
}
$iss = $payload['iss'];
if ($issuer && $iss != $issuer) {
throw new Google_Auth_Exception(
sprintf(
"Invalid issuer, %s != %s: %s",
$iss,
$issuer,
$json_body
)
);
}
// Check audience
$aud = $payload["aud"];
if ($aud != $required_audience) {
throw new Google_Auth_Exception(
sprintf(
"Wrong recipient, %s != %s:",
$aud,
$required_audience,
$json_body
)
);
}
// All good.
return new Google_Auth_LoginTicket($envelope, $payload);
}
/**
* Add a parameter to the auth params if not empty string.
*/
private function maybeAddParam($params, $name)
{
$param = $this->client->getClassConfig($this, $name);
if ($param != '') {
$params[$name] = $param;
}
return $params;
}
}