Ticket #17376: wp-17376.diff

wp-admin/admin.php

@@ -67 +67 @@
 
 nocache_headers();
 
+if( is_multisite() ) {
+        invalid_site_admin_redirect();
+}
+
 // Schedule trash collection
 if ( !wp_next_scheduled('wp_scheduled_delete') && !defined('WP_INSTALLING') )
         wp_schedule_event(time(), 'daily', 'wp_scheduled_delete');

wp-admin/includes/ms.php

@@ -742 +742 @@
         $count = get_blog_count();
         return apply_filters( 'wp_is_large_network', $count > 10000, 'sites', $count );
 }
+
+function invalid_site_admin_redirect() {
+        
+        global $current_blog;
+        
+        # Unless admin_url (minus hostname) matches base of current URL (up to wp-admin), redirect to canonical URL
+        if( preg_match( '|^http(s?)\://([^/]+)/(([^/]+/)*)wp-admin|', get_admin_url(), $canon_uri_match ) && 
+                preg_match( '|^/(([^/]+/)*)wp-admin/(.*?)$|', $_SERVER['REQUEST_URI'], $requested_uri_match ) ) {
+                
+                if( $canon_uri_match[3] != $requested_uri_match[1] ) {
+
+                        wp_redirect( 
+                                add_query_arg( 
+                                        array( 'error' => 'invalid_site' ), 
+                                        get_admin_url($current_blog->blog_id, $requested_uri_match[3])
+                                ) 
+                        );
+                        
+                }
+        }
+        
+        if( isset( $_GET['error'] ) && $_GET['error'] == 'invalid_site' ) {
+                /** We have no idea what invalid page was requested, so fire this notice for all admin pages */
+                add_action( 'all_admin_notices', 'invalid_site_admin_notice' );
+        }
+        
+}
+
+function invalid_site_admin_notice() {
+        echo '<div class="update-nag">' . __('You were redirected here because you requested the dashboard for a site that does not exist.') . '</div>';
+}
+