--- loncom/auth/lonacc.pm	2002/04/02 21:33:06	1.30
+++ loncom/auth/lonacc.pm	2002/05/07 18:49:33	1.31
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Cookie Based Access Handler
 #
-# $Id: lonacc.pm,v 1.30 2002/04/02 21:33:06 www Exp $
+# $Id: lonacc.pm,v 1.31 2002/05/07 18:49:33 www Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -178,10 +178,18 @@ sub handler {
 		    &Apache::loncommon::get_unprocessed_cgi($query,['symb']);
                 }
                 if ($ENV{'form.symb'}) {
-		    $symb=$ENV{'form.symb'};
-                    my ($map,$mid,$murl)=split(/\_\_\_/,$symb);
-                    &Apache::lonnet::symblist($map,$murl => $mid,
-                                            'last_known' => $murl);
+		    $symb=&Apache::lonnet::symbclean($ENV{'form.symb'});
+                    if (&Apache::lonnet::symbverify($symb,$requrl)) {
+                      my ($map,$mid,$murl)=split(/\_\_\_/,$symb);
+                      &Apache::lonnet::symblist($map,$murl => $mid,
+                                               'last_known' => $murl);
+		    } else {
+			$r->log_reason('Invalid symb for '.$requrl.': '.
+                                       $symb);
+		        $ENV{'user.error.msg'}=
+                                "$requrl:bre:1:1:Invalid Access";
+  	                return HTTP_NOT_ACCEPTABLE; 
+                    }
                 } else {
 	            $symb=&Apache::lonnet::symbread;
                 }