Description: Fix possible redirection on Chrome
 An insufficient check allowed users of the Google Chrome browser to be
 redirected to external domains (e.g. on login).
 [CVE-2015-3880]
Author: Marc Alexander <admin@m-a-styles.de>, Joas Schilling <nickvergessen@gmx.de>
Origin: upstream, https://github.com/phpbb/phpbb/commit/1a3350619f428d9d69d196c52128727e27ef2f04
Reviewed-by: Andreas Fischer <bantu@phpbb.com>
Last-Update: 2015-05-09
--- a/includes/functions.php
+++ b/includes/functions.php
@@ -2492,7 +2492,7 @@
 		// Attention: only able to redirect within the same domain if $disable_cd_check is false (yourdomain.com -> www.yourdomain.com will not work)
 		if (!$disable_cd_check && $url_parts['host'] !== $user->host)
 		{
-			$url = generate_board_url();
+			trigger_error('Tried to redirect to potentially insecure url.', E_USER_ERROR);
 		}
 	}
 	else if ($url[0] == '/')
@@ -2579,6 +2579,12 @@
 		}
 	}
 
+	// Make sure we don't redirect to external URLs
+	if (!$disable_cd_check && strpos($url, generate_board_url(true) . '/') !== 0)
+	{
+		trigger_error('Tried to redirect to potentially insecure url.', E_USER_ERROR);
+	}
+
 	// Make sure no linebreaks are there... to prevent http response splitting for PHP < 4.4.2
 	if (strpos(urldecode($url), "\n") !== false || strpos(urldecode($url), "\r") !== false || strpos($url, ';') !== false)
 	{