8 files changed, 494 insertions, 44 deletions
diff --git a/phpBB/phpbb/auth/auth.php b/phpBB/phpbb/auth/auth.php
index b59f0e60ec..f46a21a8ae 100644
--- a/phpBB/phpbb/auth/auth.php
+++ b/phpBB/phpbb/auth/auth.php
@@ -72,8 +72,8 @@ class auth
 
 		// Verify bitstring length with options provided...
 		$renew = false;
-		$global_length = sizeof($this->acl_options['global']);
-		$local_length = sizeof($this->acl_options['local']);
+		$global_length = count($this->acl_options['global']);
+		$local_length = count($this->acl_options['local']);
 
 		// Specify comparing length (bitstring is padded to 31 bits)
 		$global_length = ($global_length % 31) ? ($global_length - ($global_length % 31) + 31) : $global_length;
@@ -236,7 +236,7 @@ class auth
 				$sql = 'SELECT forum_id
 					FROM ' . FORUMS_TABLE;
 
-				if (sizeof($this->acl))
+				if (count($this->acl))
 				{
 					$sql .= ' WHERE ' . $db->sql_in_set('forum_id', array_keys($this->acl), true);
 				}
@@ -278,7 +278,7 @@ class auth
 		}
 
 		// If we get forum_ids not having this permission, we need to fill the remaining parts
-		if ($negate && sizeof($this->acl_forum_ids))
+		if ($negate && count($this->acl_forum_ids))
 		{
 			foreach ($this->acl_forum_ids as $f)
 			{
@@ -455,7 +455,7 @@ class auth
 	{
 		$hold_str = '';
 
-		if (sizeof($hold_ary))
+		if (count($hold_ary))
 		{
 			ksort($hold_ary);
 
@@ -514,7 +514,7 @@ class auth
 	*/
 	function acl_clear_prefetch($user_id = false)
 	{
-		global $db, $cache;
+		global $db, $cache, $phpbb_dispatcher;
 
 		// Rebuild options cache
 		$cache->destroy('_role_cache');
@@ -553,6 +553,16 @@ class auth
 			$where_sql";
 		$db->sql_query($sql);
 
+		/**
+		* Event is triggered after user(s) permission settings cache has been cleared
+		*
+		* @event core.acl_clear_prefetch_after
+		* @var	mixed	user_id	User ID(s)
+		* @since 3.1.11-RC1
+		*/
+		$vars = array('user_id');
+		extract($phpbb_dispatcher->trigger_event('core.acl_clear_prefetch_after', compact($vars)));
+
 		return;
 	}
 
@@ -928,7 +938,9 @@ class auth
 	function login($username, $password, $autologin = false, $viewonline = 1, $admin = 0)
 	{
 		global $db, $user, $phpbb_root_path, $phpEx, $phpbb_container;
+		global $phpbb_dispatcher;
 
+		/* @var $provider_collection \phpbb\auth\provider_collection */
 		$provider_collection = $phpbb_container->get('auth.provider_collection');
 
 		$provider = $provider_collection->get_provider();
@@ -982,6 +994,24 @@ class auth
 				redirect($url);
 			}
 
+			/**
+			 * Event is triggered after checking for valid username and password, and before the actual session creation.
+			 *
+			 * @event core.auth_login_session_create_before
+			 * @var	array	login				Variable containing login array
+			 * @var	bool	admin				Boolean variable whether user is logging into the ACP
+			 * @var	string	username			Username of user to log in
+			 * @var	bool	autologin			Boolean variable signaling whether login is triggered via auto login
+			 * @since 3.1.7-RC1
+			 */
+			$vars = array(
+				'login',
+				'admin',
+				'username',
+				'autologin',
+			);
+			extract($phpbb_dispatcher->trigger_event('core.auth_login_session_create_before', compact($vars)));
+
 			// If login succeeded, we will log the user in... else we pass the login array through...
 			if ($login['status'] == LOGIN_SUCCESS)
 			{
diff --git a/phpBB/phpbb/auth/provider/base.php b/phpBB/phpbb/auth/provider/base.php
index 4c49070eaf..dea27ccc25 100644
--- a/phpBB/phpbb/auth/provider/base.php
+++ b/phpBB/phpbb/auth/provider/base.php
@@ -61,7 +61,7 @@ abstract class base implements \phpbb\auth\provider\provider_interface
 	/**
 	* {@inheritdoc}
 	*/
-	public function get_auth_link_data()
+	public function get_auth_link_data($user_id = 0)
 	{
 		return;
 	}
diff --git a/phpBB/phpbb/auth/provider/db.php b/phpBB/phpbb/auth/provider/db.php
index d8c5fb72de..1adf85ee05 100644
--- a/phpBB/phpbb/auth/provider/db.php
+++ b/phpBB/phpbb/auth/provider/db.php
@@ -155,6 +155,7 @@ class db extends \phpbb\auth\provider\base
 		// Every auth module is able to define what to do by itself...
 		if ($show_captcha)
 		{
+			/* @var $captcha_factory \phpbb\captcha\factory */
 			$captcha_factory = $this->phpbb_container->get('captcha.factory');
 			$captcha = $captcha_factory->get_instance($this->config['captcha_plugin']);
 			$captcha->init(CONFIRM_LOGIN);
diff --git a/phpBB/phpbb/auth/provider/ldap.php b/phpBB/phpbb/auth/provider/ldap.php
index d32e7504eb..0789a6234d 100644
--- a/phpBB/phpbb/auth/provider/ldap.php
+++ b/phpBB/phpbb/auth/provider/ldap.php
@@ -99,7 +99,7 @@ class ldap extends \phpbb\auth\provider\base
 
 		@ldap_close($ldap);
 
-		if (!is_array($result) || sizeof($result) < 2)
+		if (!is_array($result) || count($result) < 2)
 		{
 			return sprintf($this->user->lang['LDAP_NO_IDENTITY'], $this->user->data['username']);
 		}
@@ -192,7 +192,7 @@ class ldap extends \phpbb\auth\provider\base
 
 		$ldap_result = @ldap_get_entries($ldap, $search);
 
-		if (is_array($ldap_result) && sizeof($ldap_result) > 1)
+		if (is_array($ldap_result) && count($ldap_result) > 1)
 		{
 			if (@ldap_bind($ldap, $ldap_result[0]['dn'], htmlspecialchars_decode($password)))
 			{
@@ -289,7 +289,6 @@ class ldap extends \phpbb\auth\provider\base
 	/**
 	 * {@inheritdoc}
 	 */
-
 	public function acp()
 	{
 		// These are fields required in the config table
@@ -306,9 +305,9 @@ class ldap extends \phpbb\auth\provider\base
 		return array(
 			'TEMPLATE_FILE'	=> 'auth_provider_ldap.html',
 			'TEMPLATE_VARS'	=> array(
-				'AUTH_LDAP_DN'			=> $new_config['ldap_base_dn'],
+				'AUTH_LDAP_BASE_DN'		=> $new_config['ldap_base_dn'],
 				'AUTH_LDAP_EMAIL'		=> $new_config['ldap_email'],
-				'AUTH_LDAP_PASSORD'		=> $new_config['ldap_password'],
+				'AUTH_LDAP_PASSORD'		=> $new_config['ldap_password'] !== '' ? '********' : '',
 				'AUTH_LDAP_PORT'		=> $new_config['ldap_port'],
 				'AUTH_LDAP_SERVER'		=> $new_config['ldap_server'],
 				'AUTH_LDAP_UID'			=> $new_config['ldap_uid'],
diff --git a/phpBB/phpbb/auth/provider/oauth/oauth.php b/phpBB/phpbb/auth/provider/oauth/oauth.php
index c0ce3f1fba..8809a0c6b4 100644
--- a/phpBB/phpbb/auth/provider/oauth/oauth.php
+++ b/phpBB/phpbb/auth/provider/oauth/oauth.php
@@ -63,6 +63,13 @@ class oauth extends \phpbb\auth\provider\base
 	protected $auth_provider_oauth_token_storage_table;
 
 	/**
+	* OAuth state table
+	*
+	* @var string
+	*/
+	protected $auth_provider_oauth_state_table;
+
+	/**
 	* OAuth account association table
 	*
 	* @var string
@@ -98,6 +105,13 @@ class oauth extends \phpbb\auth\provider\base
 	protected $phpbb_container;
 
 	/**
+	* phpBB event dispatcher
+	*
+	* @var \phpbb\event\dispatcher_interface
+	*/
+	protected $dispatcher;
+
+	/**
 	* phpBB root path
 	*
 	* @var string
@@ -120,14 +134,16 @@ class oauth extends \phpbb\auth\provider\base
 	* @param	\phpbb\request\request_interface	$request
 	* @param	\phpbb\user		$user
 	* @param	string			$auth_provider_oauth_token_storage_table
+	* @param	string			$auth_provider_oauth_state_table
 	* @param	string			$auth_provider_oauth_token_account_assoc
 	* @param	\phpbb\di\service_collection	$service_providers Contains \phpbb\auth\provider\oauth\service_interface
 	* @param	string			$users_table
 	* @param	\Symfony\Component\DependencyInjection\ContainerInterface $phpbb_container DI container
+	* @param	\phpbb\event\dispatcher_interface $dispatcher phpBB event dispatcher
 	* @param	string			$phpbb_root_path
 	* @param	string			$php_ext
 	*/
-	public function __construct(\phpbb\db\driver\driver_interface $db, \phpbb\config\config $config, \phpbb\passwords\manager $passwords_manager, \phpbb\request\request_interface $request, \phpbb\user $user, $auth_provider_oauth_token_storage_table, $auth_provider_oauth_token_account_assoc, \phpbb\di\service_collection $service_providers, $users_table, \Symfony\Component\DependencyInjection\ContainerInterface $phpbb_container, $phpbb_root_path, $php_ext)
+	public function __construct(\phpbb\db\driver\driver_interface $db, \phpbb\config\config $config, \phpbb\passwords\manager $passwords_manager, \phpbb\request\request_interface $request, \phpbb\user $user, $auth_provider_oauth_token_storage_table, $auth_provider_oauth_state_table, $auth_provider_oauth_token_account_assoc, \phpbb\di\service_collection $service_providers, $users_table, \Symfony\Component\DependencyInjection\ContainerInterface $phpbb_container, \phpbb\event\dispatcher_interface $dispatcher, $phpbb_root_path, $php_ext)
 	{
 		$this->db = $db;
 		$this->config = $config;
@@ -135,10 +151,12 @@ class oauth extends \phpbb\auth\provider\base
 		$this->request = $request;
 		$this->user = $user;
 		$this->auth_provider_oauth_token_storage_table = $auth_provider_oauth_token_storage_table;
+		$this->auth_provider_oauth_state_table = $auth_provider_oauth_state_table;
 		$this->auth_provider_oauth_token_account_assoc = $auth_provider_oauth_token_account_assoc;
 		$this->service_providers = $service_providers;
 		$this->users_table = $users_table;
 		$this->phpbb_container = $phpbb_container;
+		$this->dispatcher = $dispatcher;
 		$this->phpbb_root_path = $phpbb_root_path;
 		$this->php_ext = $php_ext;
 	}
@@ -188,11 +206,12 @@ class oauth extends \phpbb\auth\provider\base
 		// Get the service credentials for the given service
 		$service_credentials = $this->service_providers[$service_name]->get_service_credentials();
 
-		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table);
+		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table, $this->auth_provider_oauth_state_table);
 		$query = 'mode=login&login=external&oauth_service=' . $service_name_original;
 		$service = $this->get_service($service_name_original, $storage, $service_credentials, $query, $this->service_providers[$service_name]->get_auth_scope());
 
-		if ($this->request->is_set('code', \phpbb\request\request_interface::GET))
+		if (($service::OAUTH_VERSION === 2 && $this->request->is_set('code', \phpbb\request\request_interface::GET))
+			|| ($service::OAUTH_VERSION === 1 && $this->request->is_set('oauth_token', \phpbb\request\request_interface::GET)))
 		{
 			$this->service_providers[$service_name]->set_external_service_provider($service);
 			$unique_id = $this->service_providers[$service_name]->perform_auth_login();
@@ -208,6 +227,22 @@ class oauth extends \phpbb\auth\provider\base
 			$row = $this->db->sql_fetchrow($result);
 			$this->db->sql_freeresult($result);
 
+			/**
+			* Event is triggered before check if provider is already associated with an account
+			*
+			* @event core.oauth_login_after_check_if_provider_id_has_match
+			* @var	array									row		User row
+			* @var	array									data	Provider data
+			* @var	\OAuth\Common\Service\ServiceInterface	service	OAuth service
+			* @since 3.2.3-RC1
+			*/
+			$vars = array(
+				'row',
+				'data',
+				'service',
+			);
+			extract($this->dispatcher->trigger_event('core.oauth_login_after_check_if_provider_id_has_match', compact($vars)));
+
 			if (!$row)
 			{
 				// The user does not yet exist, ask to link or create profile
@@ -238,6 +273,18 @@ class oauth extends \phpbb\auth\provider\base
 			// Update token storage to store the user_id
 			$storage->set_user_id($row['user_id']);
 
+			/**
+			* Event is triggered after user is successfuly logged in via OAuth.
+			*
+			* @event core.auth_oauth_login_after
+			* @var    array    row    User row
+			* @since 3.1.11-RC1
+			*/
+			$vars = array(
+				'row',
+			);
+			extract($this->dispatcher->trigger_event('core.auth_oauth_login_after', compact($vars)));
+
 			// The user is now authenticated and can be logged in
 			return array(
 				'status'		=> LOGIN_SUCCESS,
@@ -247,7 +294,15 @@ class oauth extends \phpbb\auth\provider\base
 		}
 		else
 		{
-			$url = $service->getAuthorizationUri();
+			if ($service::OAUTH_VERSION === 1)
+			{
+				$token = $service->requestRequestToken();
+				$url = $service->getAuthorizationUri(array('oauth_token' => $token->getRequestToken()));
+			}
+			else
+			{
+				$url = $service->getAuthorizationUri();
+			}
 			header('Location: ' . $url);
 		}
 	}
@@ -271,7 +326,13 @@ class oauth extends \phpbb\auth\provider\base
 		}
 
 		$uri_factory = new \OAuth\Common\Http\Uri\UriFactory();
-		$current_uri = $uri_factory->createFromSuperGlobalArray($this->request->get_super_global(\phpbb\request\request_interface::SERVER));
+		$super_globals = $this->request->get_super_global(\phpbb\request\request_interface::SERVER);
+		if (!empty($super_globals['HTTP_X_FORWARDED_PROTO']) && $super_globals['HTTP_X_FORWARDED_PROTO'] === 'https')
+		{
+			$super_globals['HTTPS'] = 'on';
+			$super_globals['SERVER_PORT'] = 443;
+		}
+		$current_uri = $uri_factory->createFromSuperGlobalArray($super_globals);
 		$current_uri->setQuery($query);
 
 		$this->current_uri = $current_uri;
@@ -456,7 +517,7 @@ class oauth extends \phpbb\auth\provider\base
 	*/
 	protected function link_account_login_link(array $link_data, $service_name)
 	{
-		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table);
+		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table, $this->auth_provider_oauth_state_table);
 
 		// Check for an access token, they should have one
 		if (!$storage->has_access_token_by_session($service_name))
@@ -499,13 +560,14 @@ class oauth extends \phpbb\auth\provider\base
 	*/
 	protected function link_account_auth_link(array $link_data, $service_name)
 	{
-		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table);
+		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table, $this->auth_provider_oauth_state_table);
 		$query = 'i=ucp_auth_link&mode=auth_link&link=1&oauth_service=' . strtolower($link_data['oauth_service']);
 		$service_credentials = $this->service_providers[$service_name]->get_service_credentials();
 		$scopes = $this->service_providers[$service_name]->get_auth_scope();
 		$service = $this->get_service(strtolower($link_data['oauth_service']), $storage, $service_credentials, $query, $scopes);
 
-		if ($this->request->is_set('code', \phpbb\request\request_interface::GET))
+		if (($service::OAUTH_VERSION === 2 && $this->request->is_set('code', \phpbb\request\request_interface::GET))
+			|| ($service::OAUTH_VERSION === 1 && $this->request->is_set('oauth_token', \phpbb\request\request_interface::GET)))
 		{
 			$this->service_providers[$service_name]->set_external_service_provider($service);
 			$unique_id = $this->service_providers[$service_name]->perform_auth_login();
@@ -521,7 +583,15 @@ class oauth extends \phpbb\auth\provider\base
 		}
 		else
 		{
-			$url = $service->getAuthorizationUri();
+			if ($service::OAUTH_VERSION === 1)
+			{
+				$token = $service->requestRequestToken();
+				$url = $service->getAuthorizationUri(array('oauth_token' => $token->getRequestToken()));
+			}
+			else
+			{
+				$url = $service->getAuthorizationUri();
+			}
 			header('Location: ' . $url);
 		}
 	}
@@ -536,6 +606,18 @@ class oauth extends \phpbb\auth\provider\base
 		$sql = 'INSERT INTO ' . $this->auth_provider_oauth_token_account_assoc . '
 			' . $this->db->sql_build_array('INSERT', $data);
 		$this->db->sql_query($sql);
+
+		/**
+		 * Event is triggered after user links account.
+		 *
+		 * @event core.auth_oauth_link_after
+		 * @var    array    data    User row
+		 * @since 3.1.11-RC1
+		 */
+		$vars = array(
+			'data',
+		);
+		extract($this->dispatcher->trigger_event('core.auth_oauth_link_after', compact($vars)));
 	}
 
 	/**
@@ -544,7 +626,7 @@ class oauth extends \phpbb\auth\provider\base
 	public function logout($data, $new_session)
 	{
 		// Clear all tokens belonging to the user
-		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table);
+		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table, $this->auth_provider_oauth_state_table);
 		$storage->clearAllTokens();
 
 		return;
@@ -553,13 +635,13 @@ class oauth extends \phpbb\auth\provider\base
 	/**
 	* {@inheritdoc}
 	*/
-	public function get_auth_link_data()
+	public function get_auth_link_data($user_id = 0)
 	{
 		$block_vars = array();
 
 		// Get all external accounts tied to the current user
 		$data = array(
-			'user_id' => (int) $this->user->data['user_id'],
+			'user_id' => ($user_id <= 0) ? (int) $this->user->data['user_id'] : (int) $user_id,
 		);
 		$sql = 'SELECT oauth_provider_id, provider FROM ' . $this->auth_provider_oauth_token_account_assoc . '
 			WHERE ' . $this->db->sql_build_array('SELECT', $data);
@@ -569,7 +651,7 @@ class oauth extends \phpbb\auth\provider\base
 
 		$oauth_user_ids = array();
 
-		if ($rows !== false && sizeof($rows))
+		if ($rows !== false && count($rows))
 		{
 			foreach ($rows as $row)
 			{
@@ -616,15 +698,18 @@ class oauth extends \phpbb\auth\provider\base
 			return 'LOGIN_LINK_MISSING_DATA';
 		}
 
+		// Remove user specified in $link_data if possible
+		$user_id = isset($link_data['user_id']) ? $link_data['user_id'] : $this->user->data['user_id'];
+
 		// Remove the link
 		$sql = 'DELETE FROM ' . $this->auth_provider_oauth_token_account_assoc . "
 			WHERE provider = '" . $this->db->sql_escape($link_data['oauth_service']) . "'
-				AND user_id = " . (int) $this->user->data['user_id'];
+				AND user_id = " . (int) $user_id;
 		$this->db->sql_query($sql);
 
 		// Clear all tokens belonging to the user on this servce
 		$service_name = 'auth.provider.oauth.service.' . strtolower($link_data['oauth_service']);
-		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table);
+		$storage = new \phpbb\auth\provider\oauth\token_storage($this->db, $this->user, $this->auth_provider_oauth_token_storage_table, $this->auth_provider_oauth_state_table);
 		$storage->clearToken($service_name);
 	}
 }
diff --git a/phpBB/phpbb/auth/provider/oauth/service/twitter.php b/phpBB/phpbb/auth/provider/oauth/service/twitter.php
new file mode 100644
index 0000000000..06beac51e2
--- /dev/null
+++ b/phpBB/phpbb/auth/provider/oauth/service/twitter.php
@@ -0,0 +1,102 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\auth\provider\oauth\service;
+
+/**
+* Twitter OAuth service
+*/
+class twitter extends \phpbb\auth\provider\oauth\service\base
+{
+	/**
+	* phpBB config
+	*
+	* @var \phpbb\config\config
+	*/
+	protected $config;
+
+	/**
+	* phpBB request
+	*
+	* @var \phpbb\request\request_interface
+	*/
+	protected $request;
+
+	/**
+	* Constructor
+	*
+	* @param	\phpbb\config\config				$config
+	* @param	\phpbb\request\request_interface	$request
+	*/
+	public function __construct(\phpbb\config\config $config, \phpbb\request\request_interface $request)
+	{
+		$this->config = $config;
+		$this->request = $request;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_service_credentials()
+	{
+		return array(
+			'key'		=> $this->config['auth_oauth_twitter_key'],
+			'secret'	=> $this->config['auth_oauth_twitter_secret'],
+		);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function perform_auth_login()
+	{
+		if (!($this->service_provider instanceof \OAuth\OAuth1\Service\Twitter))
+		{
+			throw new \phpbb\auth\provider\oauth\service\exception('AUTH_PROVIDER_OAUTH_ERROR_INVALID_SERVICE_TYPE');
+		}
+
+		$storage = $this->service_provider->getStorage();
+		$token = $storage->retrieveAccessToken('Twitter');
+		$tokensecret = $token->getRequestTokenSecret();
+
+		// This was a callback request from twitter, get the token
+		$this->service_provider->requestAccessToken(
+			$this->request->variable('oauth_token', ''),
+			$this->request->variable('oauth_verifier', ''),
+			$tokensecret
+		);
+
+		// Send a request with it
+		$result = json_decode($this->service_provider->request('account/verify_credentials.json'), true);
+
+		// Return the unique identifier returned from twitter
+		return $result['id'];
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function perform_token_auth()
+	{
+		if (!($this->service_provider instanceof \OAuth\OAuth1\Service\Twitter))
+		{
+			throw new \phpbb\auth\provider\oauth\service\exception('AUTH_PROVIDER_OAUTH_ERROR_INVALID_SERVICE_TYPE');
+		}
+
+		// Send a request with it
+		$result = json_decode($this->service_provider->request('account/verify_credentials.json'), true);
+
+		// Return the unique identifier returned from twitter
+		return $result['id'];
+	}
+}
diff --git a/phpBB/phpbb/auth/provider/oauth/token_storage.php b/phpBB/phpbb/auth/provider/oauth/token_storage.php
index 023cf402ca..b0c2fd0d62 100644
--- a/phpBB/phpbb/auth/provider/oauth/token_storage.php
+++ b/phpBB/phpbb/auth/provider/oauth/token_storage.php
@@ -13,11 +13,11 @@
 
 namespace phpbb\auth\provider\oauth;
 
-
 use OAuth\OAuth1\Token\StdOAuth1Token;
 use OAuth\Common\Token\TokenInterface;
 use OAuth\Common\Storage\TokenStorageInterface;
 use OAuth\Common\Storage\Exception\TokenNotFoundException;
+use OAuth\Common\Storage\Exception\AuthorizationStateNotFoundException;
 
 /**
 * OAuth storage wrapper for phpbb's cache
@@ -43,7 +43,14 @@ class token_storage implements TokenStorageInterface
 	*
 	* @var string
 	*/
-	protected $auth_provider_oauth_table;
+	protected $oauth_token_table;
+
+	/**
+	* OAuth state table
+	*
+	* @var string
+	*/
+	protected $oauth_state_table;
 
 	/**
 	* @var object|TokenInterface
@@ -51,17 +58,24 @@ class token_storage implements TokenStorageInterface
 	protected $cachedToken;
 
 	/**
+	* @var string
+	*/
+	protected $cachedState;
+
+	/**
 	* Creates token storage for phpBB.
 	*
 	* @param	\phpbb\db\driver\driver_interface	$db
 	* @param	\phpbb\user		$user
-	* @param	string			$auth_provider_oauth_table
+	* @param	string			$oauth_token_table
+	* @param	string			$oauth_state_table
 	*/
-	public function __construct(\phpbb\db\driver\driver_interface $db, \phpbb\user $user, $auth_provider_oauth_table)
+	public function __construct(\phpbb\db\driver\driver_interface $db, \phpbb\user $user, $oauth_token_table, $oauth_state_table)
 	{
 		$this->db = $db;
 		$this->user = $user;
-		$this->auth_provider_oauth_table = $auth_provider_oauth_table;
+		$this->oauth_token_table = $oauth_token_table;
+		$this->oauth_state_table = $oauth_state_table;
 	}
 
 	/**
@@ -99,15 +113,31 @@ class token_storage implements TokenStorageInterface
 		$this->cachedToken = $token;
 
 		$data = array(
-			'user_id'		=> (int) $this->user->data['user_id'],
-			'provider'		=> $service,
 			'oauth_token'	=> $this->json_encode_token($token),
-			'session_id'	=> $this->user->data['session_id'],
 		);
 
-		$sql = 'INSERT INTO ' . $this->auth_provider_oauth_table . '
-			' . $this->db->sql_build_array('INSERT', $data);
+		$sql = 'UPDATE ' . $this->oauth_token_table . '
+				SET ' . $this->db->sql_build_array('UPDATE', $data) . '
+				WHERE user_id = ' . (int) $this->user->data['user_id'] . '
+					' . ((int) $this->user->data['user_id'] === ANONYMOUS ? "AND session_id = '" . $this->db->sql_escape($this->user->data['session_id']) . "'" : '') . "
+					AND provider = '" . $this->db->sql_escape($service) . "'";
 		$this->db->sql_query($sql);
+
+		if (!$this->db->sql_affectedrows())
+		{
+			$data = array(
+				'user_id'		=> (int) $this->user->data['user_id'],
+				'provider'		=> $service,
+				'oauth_token'	=> $this->json_encode_token($token),
+				'session_id'	=> $this->user->data['session_id'],
+			);
+
+			$sql = 'INSERT INTO ' . $this->oauth_token_table . $this->db->sql_build_array('INSERT', $data);
+
+			$this->db->sql_query($sql);
+		}
+
+		return $this;
 	}
 
 	/**
@@ -117,7 +147,8 @@ class token_storage implements TokenStorageInterface
 	{
 		$service = $this->get_service_name_for_db($service);
 
-		if ($this->cachedToken) {
+		if ($this->cachedToken)
+		{
 			return true;
 		}
 
@@ -143,7 +174,7 @@ class token_storage implements TokenStorageInterface
 
 		$this->cachedToken = null;
 
-		$sql = 'DELETE FROM ' . $this->auth_provider_oauth_table . '
+		$sql = 'DELETE FROM ' . $this->oauth_token_table . '
 			WHERE user_id = ' . (int) $this->user->data['user_id'] . "
 				AND provider = '" . $this->db->sql_escape($service) . "'";
 
@@ -153,6 +184,8 @@ class token_storage implements TokenStorageInterface
 		}
 
 		$this->db->sql_query($sql);
+
+		return $this;
 	}
 
 	/**
@@ -162,7 +195,123 @@ class token_storage implements TokenStorageInterface
 	{
 		$this->cachedToken = null;
 
-		$sql = 'DELETE FROM ' . $this->auth_provider_oauth_table . '
+		$sql = 'DELETE FROM ' . $this->oauth_token_table . '
+			WHERE user_id = ' . (int) $this->user->data['user_id'];
+
+		if ((int) $this->user->data['user_id'] === ANONYMOUS)
+		{
+			$sql .= " AND session_id = '" . $this->db->sql_escape($this->user->data['session_id']) . "'";
+		}
+
+		$this->db->sql_query($sql);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function storeAuthorizationState($service, $state)
+	{
+		$service = $this->get_service_name_for_db($service);
+
+		$this->cachedState = $state;
+
+		$data = array(
+			'user_id'		=> (int) $this->user->data['user_id'],
+			'provider'		=> $service,
+			'oauth_state'	=> $state,
+			'session_id'	=> $this->user->data['session_id'],
+		);
+
+		$sql = 'INSERT INTO ' . $this->oauth_state_table . '
+			' . $this->db->sql_build_array('INSERT', $data);
+		$this->db->sql_query($sql);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function hasAuthorizationState($service)
+	{
+		$service = $this->get_service_name_for_db($service);
+
+		if ($this->cachedState)
+		{
+			return true;
+		}
+
+		$data = array(
+			'user_id'	=> (int) $this->user->data['user_id'],
+			'provider'	=> $service,
+		);
+
+		if ((int) $this->user->data['user_id'] === ANONYMOUS)
+		{
+			$data['session_id']	= $this->user->data['session_id'];
+		}
+
+		return (bool) $this->get_state_row($data);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function retrieveAuthorizationState($service)
+	{
+		$service = $this->get_service_name_for_db($service);
+
+		if ($this->cachedState)
+		{
+			return $this->cachedState;
+		}
+
+		$data = array(
+			'user_id'	=> (int) $this->user->data['user_id'],
+			'provider'	=> $service,
+		);
+
+		if ((int) $this->user->data['user_id'] === ANONYMOUS)
+		{
+			$data['session_id']	= $this->user->data['session_id'];
+		}
+
+		return $this->get_state_row($data);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function clearAuthorizationState($service)
+	{
+		$service = $this->get_service_name_for_db($service);
+
+		$this->cachedState = null;
+
+		$sql = 'DELETE FROM ' . $this->oauth_state_table . '
+			WHERE user_id = ' . (int) $this->user->data['user_id'] . "
+				AND provider = '" . $this->db->sql_escape($service) . "'";
+
+		if ((int) $this->user->data['user_id'] === ANONYMOUS)
+		{
+			$sql .= " AND session_id = '" . $this->db->sql_escape($this->user->data['session_id']) . "'";
+		}
+
+		$this->db->sql_query($sql);
+
+		return $this;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function clearAllAuthorizationStates()
+	{
+		$this->cachedState = null;
+
+		$sql = 'DELETE FROM ' . $this->oauth_state_table . '
 			WHERE user_id = ' . (int) $this->user->data['user_id'];
 
 		if ((int) $this->user->data['user_id'] === ANONYMOUS)
@@ -171,6 +320,8 @@ class token_storage implements TokenStorageInterface
 		}
 
 		$this->db->sql_query($sql);
+
+		return $this;
 	}
 
 	/**
@@ -185,7 +336,7 @@ class token_storage implements TokenStorageInterface
 			return;
 		}
 
-		$sql = 'UPDATE ' . $this->auth_provider_oauth_table . '
+		$sql = 'UPDATE ' . $this->oauth_token_table . '
 			SET ' . $this->db->sql_build_array('UPDATE', array(
 					'user_id' => (int) $user_id
 				)) . '
@@ -218,6 +369,29 @@ class token_storage implements TokenStorageInterface
 	}
 
 	/**
+	* Checks to see if a state exists solely by the session_id of the user
+	*
+	* @param	string	$service	The name of the OAuth service
+	* @return	bool	true if they have state, false if they don't
+	*/
+	public function has_state_by_session($service)
+	{
+		$service = $this->get_service_name_for_db($service);
+
+		if ($this->cachedState)
+		{
+			return true;
+		}
+
+		$data = array(
+			'session_id'	=> $this->user->data['session_id'],
+			'provider'		=> $service,
+		);
+
+		return (bool) $this->get_state_row($data);
+	}
+
+	/**
 	* A helper function that performs the query for has access token functions
 	*
 	* @param	array	$data
@@ -232,7 +406,8 @@ class token_storage implements TokenStorageInterface
 	{
 		$service = $this->get_service_name_for_db($service);
 
-		if ($this->cachedToken instanceof TokenInterface) {
+		if ($this->cachedToken instanceof TokenInterface)
+		{
 			return $this->cachedToken;
 		}
 
@@ -244,6 +419,23 @@ class token_storage implements TokenStorageInterface
 		return $this->_retrieve_access_token($data);
 	}
 
+	public function retrieve_state_by_session($service)
+	{
+		$service = $this->get_service_name_for_db($service);
+
+		if ($this->cachedState)
+		{
+			return $this->cachedState;
+		}
+
+		$data = array(
+			'session_id'	=> $this->user->data['session_id'],
+			'provider'	=> $service,
+		);
+
+		return $this->_retrieve_state($data);
+	}
+
 	/**
 	* A helper function that performs the query for retrieve access token functions
 	* Also checks if the token is a valid token
@@ -275,6 +467,26 @@ class token_storage implements TokenStorageInterface
 	}
 
 	/**
+	 * A helper function that performs the query for retrieve state functions
+	 *
+	 * @param	array	$data
+	 * @return	mixed
+	 * @throws \OAuth\Common\Storage\Exception\AuthorizationStateNotFoundException
+	 */
+	protected function _retrieve_state($data)
+	{
+		$row = $this->get_state_row($data);
+
+		if (!$row)
+		{
+			throw new AuthorizationStateNotFoundException();
+		}
+
+		$this->cachedState = $row['oauth_state'];
+		return $this->cachedState;
+	}
+
+	/**
 	* A helper function that performs the query for retrieving an access token
 	*
 	* @param	array	$data
@@ -282,7 +494,24 @@ class token_storage implements TokenStorageInterface
 	*/
 	protected function get_access_token_row($data)
 	{
-		$sql = 'SELECT oauth_token FROM ' . $this->auth_provider_oauth_table . '
+		$sql = 'SELECT oauth_token FROM ' . $this->oauth_token_table . '
+			WHERE ' . $this->db->sql_build_array('SELECT', $data);
+		$result = $this->db->sql_query($sql);
+		$row = $this->db->sql_fetchrow($result);
+		$this->db->sql_freeresult($result);
+
+		return $row;
+	}
+
+	/**
+	 * A helper function that performs the query for retrieving a state
+	 *
+	 * @param	array	$data
+	 * @return	mixed
+	 */
+	protected function get_state_row($data)
+	{
+		$sql = 'SELECT oauth_state FROM ' . $this->oauth_state_table . '
 			WHERE ' . $this->db->sql_build_array('SELECT', $data);
 		$result = $this->db->sql_query($sql);
 		$row = $this->db->sql_fetchrow($result);
diff --git a/phpBB/phpbb/auth/provider/provider_interface.php b/phpBB/phpbb/auth/provider/provider_interface.php
index 613297cefc..35e0f559a1 100644
--- a/phpBB/phpbb/auth/provider/provider_interface.php
+++ b/phpBB/phpbb/auth/provider/provider_interface.php
@@ -166,6 +166,10 @@ interface provider_interface
 	/**
 	* Returns an array of data necessary to build the ucp_auth_link page
 	*
+	* @param int $user_id User ID for whom the data should be retrieved.
+	*						defaults to 0, which is not a valid ID. The method
+	*						should fall back to the current user's ID in this
+	*						case.
 	* @return	array|null	If this function is not implemented on an auth
 	*						provider then it returns null. If it is implemented
 	*						it will return an array of up to four elements of
@@ -181,7 +185,7 @@ interface provider_interface
 	*							'VARS'				=> array(...),
 	*						)
 	*/
-	public function get_auth_link_data();
+	public function get_auth_link_data($user_id = 0);
 
 	/**
 	* Unlinks an external account from a phpBB account.