These conversions are governed by execution consistency models, a unified way of reasoning about families of paths through programs. A platform for invivo multipath analysis of software systems. However, sage mainly uses concolic execution, while klee uses vanilla symbolic execution. A platform for invivo multipath analysis of software. The execution requires a selection of paths that are exercised by a set of data values. You can use s2e 1 to analyze binaries invivo within a full software stack. Building these tools on top of s2e took less than 770 loc and 40 person. Bugs and vulnerabilities in binary executables threaten cyber security. Symbolic execution is used in conjunction with an automated theorem prover or constraint solver based. The key idea behind symbolic execution 6,12,23 is to use symbolic values, instead of concrete data values, as input values, and to represent the values of program variables as symbolic expressions over the symbolic values. In the rest of the paper, we describe selective symbolic execution 2, execution consistency models 3, s2es apis for developing analysis tools 4, the s2e prototype 5, evaluation 6, related work 7, and conclusions 8.
S2e kvm extensions for symbolic execution analysis plugins symbolic execution engine dynamic binary translator instrumentation engine path selection plugins s2e applications libraries kernel drivers virtual hardware vm libs2e. Symbolic and concolic execution play important roles in a variety of security and software testing applications, e. Software testingdebugging is extremely time consuming, and hence techniques to automate debugging or program repair are of value. In computer science, symbolic execution also symbolic evaluation or symbex is a means of analyzing a program to determine what inputs cause each part of a program to execute. Multipath invivo analysis of complex software systems selective symbolic execution, embodied in the s2e system, automatically selects the minimal set of paths that need to be explored for a given analysis, thus reducing resource needs by orders of magnitude compared to classic symbolic execution. S2e enables the productive use of symbolic execution in large software systems with complexenvironmentinteractions, without requiring explicit environment modeling. Most instructions do not access symbolic state, so. The klee and s2e tools both of which are opensource tools, and use the stp constraint solver are widely used in many companies including micro focus fortify, nvidia, and ibm citation needed. S2e enables the productive use of symbolic execution in large software systems with complex environment interactions, without re quiring explicit environment. Conceptually, s 2 e is an automated path explorer with modular path analyzers. S2e proceedings of the sixteenth international conference. If the correctness criteria for the given program is described by a set of test cases, we will show that. This article presents s 2 e, a platform for analyzing the properties and behavior of software systems, along with its use in developing tools for comprehensive performance profiling, reverse engineering of proprietary software, and automated testing of kernelmode and usermode binaries. S2e, triton are also other mentionable opensource candidates which are worth taking.
Symbolic execution is a popular automatic approach for testing software and finding bugs. It is built around a modified version of the qemu virtual machine, and it dynamically dispatches guest machine instructions either to the host cpu for native execution or to a symbolic execution engine klee embedded inside s2e. An interpreter follows the program, assuming symbolic values for inputs rather than obtaining actual inputs as normal execution of the program would. We demonstrate s2es use in developing practical tools for comprehensive performance profiling, reverse engineering of proprietary software, and bug finding for both kernelmode and usermode binaries. A survey of symbolic execution techniques season lab. S2e proceedings of the sixteenth international conference on. S2e runs unmodified x86, x8664, or arm software stacks, including programs, libraries. A practical concolic execution engine tailored for.
S2e is a platform for writing tools that analyze the properties and behavior of software systems. E to develop performance profilers, reverse engineering tools for proprietary software, vulnerability finding tools for both kernelmode and usermode binaries, scalable file system checkers, symbolic execution engines for interpreted languages, tools for finding trojan. Symbolic execution independently proceeds on both states. Reliability analysis of component software in wireless sensor networks. Enhancing symbolic execution with veritesting june 2016. Role of symbolic execution in software testing, debugging.
A platform for invivo analysis of software systems s2e. This paper presents s2e, a platform for analyzing the properties and behavior of software systems. S2e weaves the execution back and forth between the symbolic and the concrete domain by automatically and transparently converting symbolic to concrete data and vice versa. King in article symbolic execution and program testing 6. S2e is still distinct from these even though being a distant klee fork in that is uses dynamic switching between symbolic and concrete execution, using a jit that allows onthefly translation between qemubc and llvmbc. Approaches like hybrid concolic testing 9 and symbolic jpf 12 are speci. Software security introducing symbolic execution youtube. In this article, we survey the main aspects of symbolic execution and discuss the. Test inputs are chosen based on whether they can trigger new branching behaviors of the program. S2e helps make analyses based on symbolic execution practical for large software that runs in real environments, without requiring explicit modeling of these environments. Symbolic execution is s2es default mode but you can also do concolic testing without much effort. There is a multitude of available irs, and even more approaches to transform target programs into a respective ir. Symbolic execution is a software testing technique that is useful to aid the generation of test data and in proving the program quality. Many security and software testing applications require checking whether certain.
Symbolic execution is s2e s default mode but you can also do concolic testing without much effort. S2e is built upon the klee symbolic execution engine and the qemu virtual machine emulator. Citeseerx document details isaac councill, lee giles, pradeep teregowda. A symbolic execution of function foobar, which can be effectively represented as a tree, is shown in figure 2. Distributed symbolic execution for binary software testing. The evaluation of a jump goto s updates the execution state by advancing the symbolic execution to statement s. Qemu vm with generic kvm extensions for symbolic execution c 8 16 0 1 updated may 1, 2020. Section 4 describes the implementation of a prototype system. Jan 30, 2017 desired paths can be specified in multiple ways, and s2e users can either combine existing analyzers to build a custom analysis tool, or write new analyzers using the s2e api. What insight makes s2e different from normal symbolic execution. S2e comes as a modular library that gives virtual machines.
Perhaps the most famous commercial tool that uses dynamic symbolic execution aka concolic testing is the sage tool from microsoft. S2es strength is the ability to scale to large systems, such as a full windows stack, using two new ideas. Aug 30, 2016 importantly, we take a build security in mentality, considering techniques at each phase of the development cycle that can be used to strengthen the security of software systems. S2e comes as a modular library that gives virtual machines symbolic execution and program analysis capabilities. In research we use symbolic execution but in practical there is no good tools. In this paper, we designed and implemented a hybrid automatic bug finding toolffuzzon top of. S2e runs unmodified x86, x8664, or arm software stacks, including programs, libraries, the kernel, and drivers. Intellitest generates inputs for parameterized unit tests by analyzing the branch conditions in the program. Desired paths can be specified in multiple ways, and s2e users can either combine existing analyzers to build a custom analysis tool, or write new analyzers using the s2e api. Cloud9 builds upon the klee symbolic execution engine. Symbolic execution verification condition generation fsoft ivancic et al. Symbolic execution has become a popular technique for software testing and vulnerability detection. We used chksum, md5sum, and sha1sum in coreutils to test klee, and md5sum mosml12 to test angr because angr does not support the fadvisesyscall, which is used in the coreutils applications. In computer science, symbolic execution also symbolic evaluation or symbex is a.
In the rest of the paper, we describe selective symbolic execution 2, present the execution consistency models 3, the use of s2e for developing analysis tools 4, the s2e prototype 5, evaluation 6, related work 7, and conclusions 8. Cloud9 is a parallel symbolic execution engine that scales on sharednothing clusters of commodity hardware. S2e 31 is a systemwide platform for analyzing the properties and behavior of software systems based on qemu, it uses selective symbolic execution and. S2e helps scale symbolic execution by a priori pruning parts of the executiontree that the developerwould not even look at once execution completed. The selective symbolic execution platform s2e is a platform for writing tools that analyze the properties and behavior of software systems. S2e 31 is a systemwide platform for analyzing the properties and behavior of software systems based on qemu, it uses selective symbolic execution and relaxed execution consistency models to. For more information on what klee is and what it can do, see the osdi 2008 paper. Automatic testing of symbolic execution engines via program generation and differential testing timotej kapus, cristian cadar ieeeacm international conference on automated software engineering ase 2017 october 30 november 3, 2017, urbanachampaign, il, usa. Klee is a symbolic virtual machine built on top of the llvm compiler infrastructure, and available under the uiuc open source license.
Some insights about symbolic execution i execute programs with symbols. Over the past decade, numerous symbolic execution tools have appearedboth in academia and industrydemonstrating the effectiveness of the technique in finding crashing inputs, generating test cases with high coverage, and exposing software vulnerabilities. The emergence of more and more cloud computing platforms makes it feasible to scale this technique using the concept of distributed. Symbolic execution wei le thank cristian cadar, patrice godefroid, je foster, nikolai tillmann, vijay ganesh for some of the slides 2014. Concolic testing a portmanteau of concrete and symbolic is a hybrid software verification technique that performs symbolic execution, a classical technique that treats program variables as symbolic variables, along a concrete execution testing on particular inputs path. Selecta formal system for testing and debugging programs by symbolic execution.
In this talk, i will discuss the use of symbolic execution for software testing, debugging and repair. We used s2e to build a tool that tests proprietary windows drivers and a comprehensive performance profiler, which constitutes the first use of symbolic execution in performance analysis. The use of symbolic execution for testing of realtime safety. E is a platform for writing tools that analyze the properties and behavior of software systems. Section 5 presents the kernel panic triage case study, section 6 presents the security vulnerability patching case study, and section 7 discusses the ondemand symbolic execution case study.
S2e is a platform for analysing the properties and behaviours of complex software systems through symbolic execution. Often only some families of paths are of interest to developers e. S2e is a symbolic execution engine for x86 and arm binaries. The use of symbolic execution for testing of realtime. Dynamic symbolic execution visual studio microsoft docs. Second, s2e employs virtualization to perform the desired analyses in vivo. Symbolic execution is a testing technique where program is run through an interpreter, which allows for inputs to be symbolic, as opposed to concrete. As a result, the output values computed by a program are expressed as a function of the input symbolic values.
Documentation and quick start guides for the s2e symbolic execution platform python 26 76 0 0 updated jan 2, 2020. Selective symbolic execution dependable systems lab epfl. For example, the tools sage 11 and s2e 12 adopted symbolic execution to test software systems, which intensively interact with external environments. Current discovery methods, like fuzz testing, symbolic execution and manual analysis, both have advantages and disadvantages when exercising the deeper code area in binary executables to find more bugs. Qemu vm with generic kvm extensions for symbolic execution. It can test systems ranging from command line utilities to internet servers and distributed systems, thanks to its support for a symbolic posix os environment.
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