Make sure $rule_frag has length before indexing it.

diff --git a/http/url_map.php b/http/url_map.php
index ad7541a2389c965b5a5113d26c5ec83639a6fefd..bc40a672e697578d75a23a914fe388306395ae0e 100644 (file)
--- a/http/url_map.php
+++ b/http/url_map.php
@@ -160,7 +160,7 @@ class UrlMap
 
           // If this fragment is a key to be extracted, do so into a temporary
           // array.
-          if ($rule_frag[0] == '{' && substr($rule_frag, -1) == '}') {
+          if (strlen($rule_frag) && $rule_frag[0] == '{' && substr($rule_frag, -1) == '}') {
             $key = substr($rule_frag, 1, -1);
             $extractions[$key] = $fragments[$i];
           }