Off-The-Shelf (OTS) software components are the cornerstone of modern systems, including safety-critical ones. However, the dependability of OTS components is uncertain due to the lack of source code, design artifacts and test cases, since only their binary code is supplied. Fault injection in components' binary code is a solution to understand the risks posed by buggy OTS components. In this paper, we consider the problem of the accurate mutation of binary code for fault injection purposes. Fault injection emulates bugs in high-level programming constructs (assignments, expressions, function calls, ...) by mutating their translation in binary code. However, the semantic gap between the source code and its binary translation often leads to inaccurate mutations. We propose Faultprog, a systematic approach for testing the accuracy of binary mutation tools. Faultprog automatically generates synthetic programs using a stochastic grammar, and mutates both their binary code with the tool under test, and their source code as reference for comparisons. Moreover, we present a case study on a commercial binary mutation tool, where Faultprog was adopted to identify code patterns and compiler optimizations that affect its mutation accuracy.

Network Function Virtualization (NFV) is an emerging solution that aims at improving the flexibility, the efficiency and the manageability of networks, by leveraging virtualization and cloud computing technologies to run network appliances in software. However, the “softwarization” of network functions raises reliability concerns, as they will be exposed to faults in commodity hardware and software components. In this paper, we propose a methodology for the dependability evaluation and benchmarking of NFV Infrastructures (NFVIs), based on fault injection. We discuss the application of the methodology in the context of a virtualized IP Multimedia Subsystem (IMS), and the pitfalls in the design of a reliable NFVI.

The reuse of software components is a common practice in commercial applications and increasingly appearing in safety critical systems as driven also by cost considerations. This practice puts dependability at risk, as differing operating conditions in different reuse scenarios may expose residual software faults in the components. Consequently, software fault injection techniques are used to assess how residual faults of reused software components may affect the system, and to identify appropriate counter-measures. As fault injection in components’ code suffers from a number of practical disadvantages, it is often replaced by error injection at the component interface level. However, it is still an open issue, whether such injected errors are actually representative of the effects of residual faults. To this end, we propose a method for analyzing how software faults turn into interface errors, with the ultimate aim of supporting more representative interface error injection experiments. Our analysis in the context of widely used software libraries reveals that existing interface error models are not suitable for emulating software faults, and provides useful insights for improving the representativeness of interface error injection.