Added ClassSecurityInformation class. This class is equivalent to

ClassSecurityInfo except that access to unprotected subobjects is
denied. Use this class to provide more explicit, and, thus more
secure, protection for methods.

lib/python/AccessControl/SecurityInfo.py

@@ -193,6 +193,10 @@ class ClassSecurityInfo(SecurityInfo):
             LOG('SecurityInfo', WARNING, 'Class "%s" had conflicting '
                 'security declarations' % classobj.__name__)
 
+class ClassSecurityInformation(ClassSecurityInfo):
+    # Default policy is disallow
+    access = 0
+
 _moduleSecurity = {}
 
 def secureModule(mname, *imp):