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Leuven, Belgium

Jacobs B.,IMinds DistriNet | Bosnacki D.,TU Eindhoven | Kuiper R.,TU Eindhoven
Leibniz International Proceedings in Informatics, LIPIcs | Year: 2015

We propose an approach for the modular specification and verification of total correctness properties of object-oriented programs. We start from an existing program logic for partial correctness based on separation logic and abstract predicate families. We extend it with call permissions qualified by an arbitrary ordinal number, and we define a specification style that properly hides implementation details, based on the ideas of using methods and bags of methods as ordinals, and exposing the bag of methods reachable from an object as an abstract predicate argument. These enable each method to abstractly request permission to call all methods reachable by it any finite number of times, and to delegate similar permissions to its callees. We illustrate the approach with several examples. © Bart Jacobs, Dragan Bosnacki, and Ruurd Kuiper;.

Clarke D.,IMinds DistriNet | Noble J.,Victoria University of Wellington | Wrigstad T.,Uppsala University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Aliasing occurs when two or more references to an object exist within the object graph of a running program. Although aliasing is essential in object-oriented programming as it allows programmers to implement designs involving sharing, it is problematic because its presence makes it difficult to reason about the object at the end of an alias - via an alias, an object's state can change underfoot. © Springer-Verlag Berlin Heidelberg 2013.

Proenca J.,University of Minho | Clarke D.,IMinds DistriNet
Communications in Computer and Information Science | Year: 2013

This paper studies complex coordination mechanisms based on constraint satisfaction. In particular, it focuses on data-sensitive connectors from the Reo coordination language. These connectors restrict how and where data can flow between loosely-coupled components taking into account the data being exchanged. Existing engines for Reo provide a very limited support for data-sensitive connectors, even though data constraints are captured by the original semantic models for Reo. When executing data-sensitive connectors, coordination constraints are not exhaustively solved at compile time but at runtime on a per-need basis, powered by an existing SMT (satisfiability modulo theories) solver. To deal with a wider range of data types and operations, we abstract data and reduce the original constraint satisfaction problem to a SAT problem, based on a variation of predicate abstraction. We show soundness and completeness of the abstraction mechanism for well-defined constraints, and validate our approach by evaluating the performance of a prototype implementation with different test cases, with and without abstraction. © Springer-Verlag Berlin Heidelberg 2013.

Patrignani M.,IMinds DistriNet | Clarke D.,Uppsala University
Computer Languages, Systems and Structures | Year: 2015

Abstract Protected module architectures (PMAs) are isolation mechanisms of emerging processors that provide security building blocks for modern software systems. Reasoning about these building blocks means reasoning about elaborate assembly code, which can be very complex due to the loose structure of the code. One way to overcome this complexity is providing the code with a well-structured semantics. This paper presents one such semantics, namely a fully abstract trace semantics, for an assembly language enhanced with PMA. The trace semantics represents the behaviour of protected assembly code with simple abstractions, unburdened by low-level details, at the maximum degree of precision. Furthermore, it captures the capabilities of attackers to protected code and simplifies the formulation of a secure compiler targeting PMA-enhanced assembly language. © 2015 Elsevier Ltd.

Clarke D.,IMinds DistriNet | Ostlund J.,Uppsala University | Sergey I.,IMinds DistriNet | Wrigstad T.,Uppsala University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013

Ownership types were devised nearly 15 years ago to provide a stronger notion of protection to object-oriented programming languages. Rather than simply protecting the fields of an object from external access, ownership types protect also the objects stored in the fields, thereby enabling an object to claim (exclusive) ownership of and access to other objects. Furthermore, this notion is statically enforced by now-standard type-checking techniques. Originating as the formalisation of the core of Flexible Alias Protection, ownership types have since been extended and adapted in many ways, and the notion of protection provided has been refined into topological and encapsulation dimensions. This article surveys the various flavours of ownership types that have been developed over the years, along with the many applications and other developments. The chapter concludes by suggesting some directions for future work. © Springer-Verlag Berlin Heidelberg 2013.

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