Secure Information Flow by Model Checking Pushdown System

TL;DR

This paper introduces a semantic-based model checking approach for secure information flow in procedural programs using pushdown systems and LTL, improving precision and efficiency over traditional type-based methods.

Contribution

It presents a novel pushdown system model with self-composition and LTL specification for noninterference, enhancing accuracy and efficiency in inter-procedural information flow analysis.

Findings

Self-composition techniques significantly improve verification efficiency.

The approach overcomes conservativeness of type-based static analysis.

Experimental results demonstrate practical effectiveness in realistic scenarios.

Abstract

We propose an approach on model checking information flow for imperative language with procedures. We characterize our model with pushdown system, which has a stack of unbounded length that naturally models the execution of procedural programs. Because the type-based static analysis is sometimes too conservative and rejects safe program as ill-typed, we take a semantic-based approach by self-composing symbolic pushdown system and specifying noninterference with LTL formula. Then we verify this LTL-expressed property via model checker Moped. Except for overcoming the conservative characteristic of type-based approach, our motivation also includes the insufficient state of arts on precise information flow analysis under inter-procedural setting. To remedy the inefficiency of model checking compared with type system, we propose both compact form and contracted form of self-composition. According to our experimental results, they can greatly increase the efficiency of realistic verification. Our method provides flexibility on separating program abstraction from noninterference verification, thus could be expected to use on different programming languages.