Biblio

Program verification techniques have gained increasing popularity in academic and industrial circles during the last years. Predicate abstraction is a traditional and practical verification technique, which can solve the problem of state space explosion pretty well. Many software verification tools have implemented it. But these implementations are not user-friendly, or scalable. Aimed at these problems, we describe and implement a new automatic predicate abstraction framework, CChecker, for proving the safety of procedural programs with integer assignments. CChecker is a whole system composed of two parts: front and back end. The front end preprocesses and parses the source programs into logic models based on Clang. And the back end resolves the models based on Z3 to get software safety property. At last, the experiments show the potential of CChecker.

Modern automotive embedded software is mostly designed using model-based design tools such as Simulink or SCADE, and source code is generated automatically from the models. Formal proof using symbolic model checking has been integrated in these tools and can provide a higher assurance by proving safety-critical properties. Our experience shows that proving properties involving time is rather challenging when they involve long durations and timers. These properties are generally not inductive and even advanced techniques such as PDR/IC3 are unable to handle them on production models in reasonable time. In this paper, we first present our industrial use case and comment on the results obtained with the existing model checkers. Then we present our invariant generator and methodology for selecting invariants according to physical dimensions. They enable the proof of properties with long-running timers. Finally, we discuss their implementation and benchmarks.

HACL* is a verified portable C cryptographic library that implements modern cryptographic primitives such as the ChaCha20 and Salsa20 encryption algorithms, Poly1305 and HMAC message authentication, SHA-256 and SHA-512 hash functions, the Curve25519 elliptic curve, and Ed25519 signatures. HACL* is written in the F* programming language and then compiled to readable C code. The F* source code for each cryptographic primitive is verified for memory safety, mitigations against timing side-channels, and functional correctness with respect to a succinct high-level specification of the primitive derived from its published standard. The translation from F* to C preserves these properties and the generated C code can itself be compiled via the CompCert verified C compiler or mainstream compilers like GCC or CLANG. When compiled with GCC on 64-bit platforms, our primitives are as fast as the fastest pure C implementations in OpenSSL and libsodium, significantly faster than the reference C code in TweetNaCl, and between 1.1x-5.7x slower than the fastest hand-optimized vectorized assembly code in SUPERCOP. HACL* implements the NaCl cryptographic API and can be used as a drop-in replacement for NaCl libraries like libsodium and TweetNaCl. HACL* provides the cryptographic components for a new mandatory ciphersuite in TLS 1.3 and is being developed as the main cryptographic provider for the miTLS verified implementation. Primitives from HACL* are also being integrated within Mozilla's NSS cryptographic library. Our results show that writing fast, verified, and usable C cryptographic libraries is now practical.

In this ubiquitous IoT (Internet of Things) era, web services have become a vital part of today's critical national and public sector infrastructure. With the industry wide adaptation of service-oriented architecture (SOA), web services have become an integral component of enterprise software eco-system, resulting in new security challenges. Web services are strategic components used by wide variety of organizations for information exchange on the internet scale. The public deployments of mission critical APIs opens up possibility of software bugs to be maliciously exploited. Therefore, vulnerability identification in web services through static as well as dynamic analysis is a thriving and interesting area of research in academia, national security and industry. Using OWASP (Open Web Application Security Project) web services guidelines, this paper discusses the challenges of existing standards, and reviews new techniques and tools to improve services security by detecting vulnerabilities. Recent vulnerabilities like Shellshock and Heartbleed has shifted the focus of risk assessment to the application layer, which for majority of organization means public facing web services and web/mobile applications. RESTFul services have now become the new service development paradigm normal; therefore SOAP centric standards such as XML Encryption, XML Signature, WS-Security, and WS-SecureConversation are nearly not as relevant. In this paper we provide an overview of the OWASP top 10 vulnerabilities for web services, and discuss the potential static code analysis techniques to discover these vulnerabilities. The paper reviews the security issues targeting web services, software/program verification and security development lifecycle.

This paper presents verification and model based checking of the Trivial File Transfer Protocol (TFTP). Model checking is a technique for software verification that can detect concurrency defects within appropriate constraints by performing an exhaustive state space search on a software design or implementation and alert the implementing organization to potential design deficiencies that are otherwise difficult to be discovered. The TFTP is implemented on top of the Internet User Datagram Protocol (UDP) or any other datagram protocol. We aim to create a design model of TFTP protocol, with adding window size, using Promela to simulate it and validate some specified properties using spin. The verification has been done by using the model based checking tool SPIN which accepts design specification written in the verification language PROMELA. The results show that TFTP is free of live locks.