Resource Contracts for Java

Static analyzers have become increasingly popular both as developer tools and as subjects of empirical studies. Whereas static analysis tools exist for disparate programming languages, the bulk of the empirical research has focused on the popular Java programming language. In this paper, we investigate to what extent some known results about using static analyzers for Java change when considering C#-another popular object-oriented language. To this end, we combine two replications of previous Java studies. First, we study which static analysis tools are most widely used among C# developers, and which warnings are more commonly reported by these tools on open-source C# projects. Second, we develop and empirically evaluate EagleRepair: a technique to automatically fix code in response to static analysis warnings; this is a replication of our previous work for Java [20]. Our replication indicates, among other things, that 1) static code analysis is fairly popular among C# developers too; 2) Re-Sharper is the most widely used static analyzer for C#; 3) several static analysis rules are commonly violated in both Java and C# projects; 4) automatically generating fixes to static code analysis warnings with good precision is feasible in C#. The EagleRepair tool developed for this research is available as open source.

The two broad approaches to discover properties of programs---static and dynamic analyses---have complementary strengths: static techniques perform exhaustive exploration and prove upper bounds on program behaviors, while the dynamic analysis of test cases provides concrete evidence of these behaviors and promise low false alarm rates. In this paper, we present DynaBoost, a system which uses information obtained from test executions to prioritize the alarms of a static analyzer. We instrument the program to dynamically look for dataflow behaviors predicted by the static analyzer, and use these results to bootstrap a probabilistic alarm ranking system, where the user repeatedly inspects the alarm judged most likely to be a real bug, and where the system re-ranks the remaining alarms in response to user feedback. The combined system is able to exploit information that cannot be easily provided by users, and provides significant improvements in the human alarm inspection burden: by 35% compared to the baseline ranking system, and by 89% compared to an unaided programmer triaging alarm reports.

Static code analysis is widely used to support the development of high-quality software. It helps developers detect potential bugs and security vulnerabilities in a program's source code without executing it. While the potential benefits of static analysis tools are beyond question, their usability is often criticised and prevents software developers from using static analysis to its full potential. In the past decade, researchers have studied developer needs and contrasted them to available static analysis tool functionalities. In this paper, we summarize the main design challenges for building usable static analysis tools, and show that they revolve around the notion of explainability, which is a subarea of usability. We present existing analysis tools and current research in static analysis usability, and detail how they approach those challenges. This leads us to proposing potential lines of future work in explainability for static analysis, namely turning static analysis tools into assistants and teachers.

We present a framework for (static) verification of general resource usage program properties. The framework extends the criteria of correctness as the conformance of a program to a specification expressing non-functional global properties, such as upper and lower bounds on execution time, memory, energy, or user defined resources, given as functions on input data sizes. A given specification can include both lower and upper bound resource usage functions, i.e., it can express intervals where the resource usage is supposed to be included in. We have defined an abstract semantics for resource usage properties and operations to compare the (approximated) intended semantics of a program (i.e., the specification) with approximated semantics inferred by static analysis. These operations include the comparison of arithmetic functions (e.g., polynomial, exponential or logarithmic functions). A novel aspect of our framework is that the static checking of assertions generates answers that include conditions under which a given specification can be proved or disproved. For example, these conditions can express intervals of input data sizes such that a given specification can be proved for some intervals but disproved for others. We have implemented our techniques within the Ciao/CiaoPP system in a natural way, so that the novel resource usage verification blends in with the CiaoPP framework that unifies static verification and static debugging (as well as run-time verification and unit testing).

With the advent of GPU computing, profiling tools are now widely used to assist developers in identifying and solving performance bottlenecks. Those tools are commonly relying on hardware performance counters to grant users the access to low-level activities. Considering the increasing complexity of modern GPUs and also the efforts needed to associate program behaviors with hardware events, it is not trivial to construct the profiling tools with assured correctness. As a result, profiling tools should be strictly validated to make sure that the program behaviors and resource usages can be correctly captured and analyzed. To aid the validation, we create a testing prototype DELTA, on top of the open-source Radeon Open Compute platform (ROCm), to investigate the values of the derived profiling metrics and their underlying basic counters. The tests of DELTA are generally based on the classical microbenchmarks, which are capable to control program behaviors to generate predictable statistics. Differing from prior dissecting works, our tests are to examine the profiled results and to compare against desired patterns, reporting whether the profiling tools are correctly working with appropriate data collection and processing. This paper presents the validation methodology and experimental results of cache and main memory on the recent GPUs and ROCm platform, and the case studies demonstrate that the tests are helpful to scrutinize the profiling tools.

The estimation and control of resource usage is now an important challenge in an increasing number of computing systems. In particular, requirements on timing and energy arise in a wide variety of applications such as internet of things, cloud computing, health, transportation, and robots. At the same time, parallel computing, with (heterogeneous) multi-core platforms in particular, has become the dominant paradigm in computer architecture. Predicting resource usage on such platforms poses a difficult challenge. Most work on static resource analysis has focused on sequential programs, and relatively little progress has been made on the analysis of parallel programs, or more specifically on parallel logic programs. We propose a novel, general, and flexible framework for setting up cost equations/relations which can be instantiated for performing resource usage analysis of parallel logic programs for a wide range of resources, platforms, and execution models. The analysis estimates both lower and upper bounds on the resource usage of a parallel program (without executing it) as functions on input data sizes. In addition, it also infers other meaningful information to better exploit and assess the potential and actual parallelism of a system. We develop a method for solving cost relations involving the max function that arise in the analysis of parallel programs. Finally, we instantiate our general framework for the analysis of logic programs with Independent And-Parallelism, report on an implementation within the CiaoPP system, and provide some experimental results. To our knowledge, this is the first approach to the cost analysis of parallel logic programs.

The static code analysis tools are a fundamental instruments to validate the developed code. They allow detecting bugs (as memory leak, accessing arrays out of bounds, etc.. ), structural errors and preventing entire classes of errors. This work refers to the Parasoft's tool It helps developers prevent and eliminate defects using rules tuned to nd code patterns that lead to reliability, performance, and security problems. To be practical, the static analysis must be seamlessly in- tegrated into the team's work- ow. The `continuous static analysis' allows executing automatically the analysis when the new code is released. In this way is possible to realize a further automation in the software development executing the tool during the night or weekend. The time saved to run the tool can be used to analyze and correct the bugs. When you deal with static analysis, it's important to under- line the problem of false positive. It would be attractive if we could develop a tool that could intercept all defects in a given piece of software with certainty. Not all real errors can always be caught, and not all errors caught can always be real. This work presents a quantitative evaluation on the percentile of false positive generated by C++test.

On the effectiveness of phase based regression models to trade power and performance using dynamic processor adaptation

Leveraging and acting on the results of static analysis is a well-known best practice. Static analysis also is an integral part of software quality assurance which is highlighted by the inclusion of static analysis results in software quality models like ColumbusQM and Quamoco. Although there are studies that explore if tools for static analysis are used and how they are configured, few publications explore the longitudinal effects of acting on static analysis results on software and on the evolution of software. Especially effects on quality criteria, e.g., software quality metrics, defects, or readability are missing. With our research, we will bridge this gap and measure the effects of static analysis on software quality evolution. We will measure the effect the removal of code that generates static analysis warnings has on software quality metrics. Furthermore, we will measure long term effects on external quality attributes, e.g., reported issues and defects. Finally, we want to predict false positives of static analysis warnings by training predictive models on our collected data.

Smart contracts are executable programs that enable the building of a\nprogrammable trust mechanism between multiple entities without the need of a\ntrusted third-party. Researchers have developed several security scanners in\nthe past couple of years. However, many of these analyzers either do not scale\nwell, or if they do, produce many false positives. This issue is exacerbated\nwhen bugs are triggered only after a series of interactions with the functions\nof the contract-under-test. A depth-n vulnerability, refers to a vulnerability\nthat requires invoking a specific sequence of n functions to trigger. Depth-n\nvulnerabilities are time-consuming to detect by existing automated analyzers,\nbecause of the combinatorial explosion of sequences of functions that could be\nexecuted on smart contracts.\n In this paper, we present a technique to analyze depth-n vulnerabilities in\nan efficient and scalable way by combining symbolic execution and data\ndependency analysis. A significant advantage of combining symbolic with static\nanalysis is that it scales much better than symbolic alone and does not have\nthe problem of false positive that static analysis tools typically have. We\nhave implemented our technique in a tool called MPro, a scalable and automated\nsmart contract analyzer based on the existing symbolic analysis tool\nMythril-Classic and the static analysis tool Slither. We analyzed 100 randomly\nchosen smart contracts on MPro and our evaluation shows that MPro is about\nn-times faster than Mythril-Classic for detecting depth-n vulnerabilities,\nwhile preserving all the detection capabilities of Mythril-Classic.\n

Security certification of mobile platforms is usually a lengthy process. Apart from internal development and testing, it requires hiring a consultancy for guidance and certification. Consultants start with code reviews to identify potential vulnerabilities and subsequently conduct independent tests in their laboratory. Typically consultancy is expensive. We propose a technique to statically analyze the secure mobile platform source code to identify some of the potential vulnerabilities typically detected by the consultants. We have devised a set of patterns in code that are typically flagged by consultants as vulnerabilities. The presence of each such pattern is detected by custom developed checkers. A prototype implementation tool called SVAT (Static Vulnerability Analysis Tool) containing custom checkers has been developed by extending the Clang static analysis tool. SVAT is a collection of custom checkers developed to detect the vulnerabilities in TEE. We illustrate the working of our tool on OP-TEE, an open source implementation of TEE (Trusted Execution Environment), a typical environment that runs in mobile platforms to assure security. SVAT is currently not publicly available.

We describe a procedure based on an existing static timing analysis tool for selecting path delay faults to target during test generation. The use of an existing static timing analysis tool ensures that a state-of-the-art process can be used for estimating path delays. However, static timing analysis, by itself, can be inaccurate as it does not take into consideration conditions that are necessary for detecting path delay faults. In the proposed method, these conditions are captured as what are called input necessary assignments, which static timing analysis tools are able to use. By providing the static timing analysis process with the input necessary assignments for a selected path, the static timing analysis process can estimate the delay of the path more accurately. It can also identify additional paths whose delays are at least as high as those of the selected paths. Thus, feeding back the input necessary assignments to the static timing analysis process enhances the correlation between static timing analysis and actual timing of tests on silicon. The result is a set of potentially detectable path delay faults associated with critical paths based on more accurate estimates of the path delays that can be exhibited by a test set, compared with the set that would be obtained by static timing analysis alone.

The past decade has witnessed an explosive increase in the scale, intensity and sophistication of cyber attacks. While software vendors have significantly increased their efforts on security, they are almost always playing catch up. As a result, security-conscious organizations and individuals have come to expect their system administrators to deploy an array of tools and techniques to stay a step ahead of the hackers. While developer-oriented security tools rely mainly on static analysis, runtime analysis and policy enforcement are the mechanisms of choice in administrator-oriented tools. Runtime techniques offer increased automation and precision over static analysis, thus addressing the needs of administrators who don't have the time or resources needed to acquire extensive knowledge about the internals of a software system. In this talk, I will begin by summarizing some of the significant advances that have been achieved in the past few years in the context of software vulnerability mitigation, including buffer overflow defenses, and more recently, the impressive results that have been achieved using dynamic information-flow analysis for blocking the most popular exploits today, including SQL and command injection and cross-site scripting. I will then proceed to describe dynamic analysis and enforcement techniques aimed at another high-profile security problem faced today, namely, malware defense. Our initial target in this regard has been on dynamic analysis techniques for extracting high-level models of program behavior. These models could be used in a variety of applications such as intrusion detection, vulnerability analysis and security policy verification. More recently, interesting advances have been made in the context of security policy development, where a combination of static and dynamic analysis techniques have been developed to synthesize low-level, enforceable policies that achieve a high-level goal such as protecting system integrity. Finally, I will conclude the talk with a discussion of some research opportunities and challenges in software security.

Some trade-offs in reducing the overhead of assertion run-time checks via static analysis

Embedded system security is often compromised when "trusted" software is subverted to result in unintended behavior, such as leakage of sensitive data or execution of malicious code. Several countermeasures have been proposed in the literature to counteract these intrusions. A common underlying theme in most of them is to define security policies at the system level in an application-independent manner and check for security violations either statically or at run time. In this paper, we present a methodology that addresses this issue from a different perspective. It defines correct execution as synonymous with the way the program was intended to run and employs a dedicated hardware monitor to detect and prevent unintended program behavior. Specifically, we extract properties of an embedded program through static program analysis and use them as the bases for enforcing permissible program behavior at run time. The processor architecture is augmented with a hardware monitor that observes the program's dynamic execution trace, checks whether it falls within the allowed program behavior, and flags any deviations from expected behavior to trigger appropriate response mechanisms. We present properties that capture permissible program behavior at different levels of granularity, namely inter-procedural control flow, intra-procedural control flow, and instruction-stream integrity. We outline a systematic methodology to design application-specific hardware monitors for any given embedded program. Hardware implementations using a commercial design flow, and cycle-accurate performance simulations indicate that the proposed technique can thwart several common software and physical attacks, facilitating secure program execution with minimal overheads