Tech Report CS-06-12
ASM Relational Transducer Security Policies
Leo A. Meyerovich, Joel H.W. Weinberger, Colin S. Gordon and Shriram Krishnamurthi
We present a model of the security policy for the Web-based Continue conference management tool. The policy model and properties are written as ASM Relational Transducers, which we extend with a module system in order to simplify the handling of conflicting updates. We assume prior familiarity with the security policy concerns surrounding Continue. First, we review the ASM Relational Transducer modeling and property language. Then we describe the basic structure of our policy implementation and demonstrate the ability to model useful properties in the original core ASM language. We exploring the use of the unmodified modeling language in a security policy context and describe typical ASM Relational Transducer complexity concerns and how these minimally impact our implementation. Next, we discuss difficulties encountered in representing our policy and properties in the standard ASM language, including our implementation in the appendices. Following the description of adapting ASMs for use in security modeling, we introduce policy modules and a composition operator to overcome the difficulty of programming in the original language known as the consistent update problem. Finally, we describe a reduction from our extended language to the original language, and prove it satisfies our required correctness property.
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