- $returl = $gpex_url.gpex_make_params($gpex_challenge,$privkey,$datafields);
- http_redirect($returl);
+ $returnurls = trim($returnurls);
+ if (empty($returnurls) || @preg_match($returnurls, $gpex_url)) {
+ $returl = $gpex_url . gpex_make_params($gpex_challenge, $privkey, $datafields, $charset);
+ http_redirect($returl);
+ }