Use the predefined rtrim() function instead of a while loop.

lib/SimpleSAML/Configuration.php

@@ -416,10 +416,8 @@ class SimpleSAML_Configuration
             $path = $this->getBaseDir().$path;
         }
 
-        /* Remove trailing slashes. */
-        while (substr($path, -1) === '/') {
-            $path = substr($path, 0, -1);
-        }
+        // remove trailing slashes
+        $path = rtrim($path, '/');
 
         return $path;
     }

lib/SimpleSAML/Utils/System.php

@@ -114,10 +114,8 @@ class System
             $base = $config->getBaseDir();
         }
 
-        // remove trailing slashes from $base
-        while (substr($base, -1) === '/') {
-            $base = substr($base, 0, -1);
-        }
+        // remove trailing slashes
+        $base = rtrim($base, '/');
 
         // check for absolute path
         if (substr($path, 0, 1) === '/') {