Riechmann, Thomas ;
Hauck, Franz J.
:
Meta Objects for Access Control: Extending Capability-Based Security.
Erlangen:
FAU.
1998
TR-I4-97-15.- Interner Bericht.
6 Seiten.
Abstract:
Object-based programming is becoming more and more popular
and is currently conquering the world of distributed programming
models. In object-based systems, access control is often based on
capabilities, as capability-based security is a well-known paradigm.
It has been extended by means to restrict, revoke, and expire capa-
bilities.
On the other hand, capabilities have serious drawbacks. First, in ob-
ject-based systems, programming is based on the frequent exchange
of object references (i.e., capabilities). Thus, it is hard to check
which parts of an application are able to gain control of a certain ca-
pability. This becomes even harder if we consider distributed ob-
ject-based systems like Java RMI and CORBA. Second, a capability
usually cannot prevent method invocations from leaking unprotect-
ed references as return values. Transitive access control is not pos-
sible in a transparent way, which is independent of the code describ-
ing the invocation.
We present a new security paradigm based on meta objects. Meta
objects can be attached to object references and control access to the
corresponding objects. Meta objects offer the same functionality as
capability-based security. In addition, they can be used for implicit
and transitive access control of object references passed as a param-
eter or as a result. Such a reference can be automatically protected
by the meta object by attaching itself or another meta object to the
reference before passing it on.
Meta objects can implement arbitrary and user-defined security pol-
icies. They help to separate security policies from application code,
and thus support reuse.
