symbolic execution and program testing

We propose a novel technique for worst-case execution time testing combining symbolic execution and evolutionary algorithms, which we call . Symbolic execution and program testing Commun. A version of this paper was originally presented at the First International Workshop on Automated Program Analysis, Testing and Verification, held in Limerick, Ireland, 4-5 June 2000. .

Symbolic Execution and Program Testing (2/2) We can prove the correctness of each path by executing it symbolically as follows: Place ASSUME at the beginning of the path and PROVE at the end of the path Execute the path symbolically If the PROVE at the end of the path displays true, the path is correct, otherwise it is not Model checking can handle multi-thread systems because it is specified in the FSM provided as input, however, symbolic execution .

In symbolic execution you only provide your program and the symbolic execution engine will examine all the feasible paths to generate test inputs or check assertions. When symbolic exe-

CACM, 19(7):385-394, 1976. We provide a two-fold generalization of tra-ditional symbolic execution based approaches. Mingzhe Wang, Jie Liang, Yuanliang Chen, Yu Jiang, Xun Jiao, Han Liu, Xibin Zhao, Jiaguang Sun.

To explore another path in the program, concolic execution derives a The paper is a tutorial on symbolic execution and how it may be used in software testing and in particular the testing of commercial data-processing (DP) software. The advanced method of symbolic evaluation can be applied to program testing situations with results close to those of formal correctness proofs?but without the high cost. Symbolic execution is a software testing technique that is useful to aid the generation of test data and in proving the program quality. To ensure feasibil-ity of symbolic execution, even small programs must cur- Our approach records an actual run of the program un-der test on a well-formed input, symbolically evaluates the recorded trace, and gathers constraints on inputs capturing how the program uses these. 4: Symbolic Execution . King Week 3: (Tuesday - Eric) MultiSE: Multi-Path Symbolic Execution using Value Summaries (Thursday - Eric A Survey of Symbolic Execution Techniques. Steps to use Symbolic Execution: The execution requires a selection of paths that are exercised by a set of data values. Symbolic execution then automatically explores hundreds of thousands of paths through the system, while analyzers . However, the scal-ability of symbolic execution is often limited by path explosion, i.e., the number of symbolic states representing the paths under exploration quickly explodes as execution goes on. Early work on symbolic execution Robert S. Boyer, Bernard Elspas, and Karl N. Levitt. Performance profiling can benefit from test cases that hit high-cost executions of programs. Instead of supplying the normal inputs to a program (e.g. In ICRS, pages 234- 245, 1975. . Symbolic Execution: The term symbolic execution refers to an execution or run of a program P on sym-bolic inputs (i.e., inputs are not concrete) but instead range over all values from the input domain of the program P. Symbolic execution of a program P can be acheived on a computer by executing the program P symbolically using an interpreter or a symbolic virtual machine, e.g., the KLEE . To solve this problem, recent studies have proposed hybrid fuzzers that observe the context of a target program using symbolic execution; these fuzzers generate test cases to bypass the sanity check. 3.1. u = 1.0, and at the same time using symbolic execution to collect the constraints of the followed program path.

Since program execution may depend on the user input, it is a challenge to select suitable values in a way that allows thorough testing. ACM , 19(7), 385-394 Published February 15, 1976 J.

(most cited) Leon J. Osterweil and Lloyd D. Fosdick. ATG with Fuzzing. The video then goes through several of the examples from the KLEE website and . concolic vs. keeping all paths in memory, interpretation vs. instrumen- Before we describe compilation-based symbolic execution in detail, this section summarizes some relevant background information. Symbolic execution is a white-box technique that executes a program symbolically, computes constraints along different paths, and uses a constraint solver to generate inputs that satisfy the collected constraints along each path. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): We present results for the "Impact Project Focus Area " on the topic of symbolic execution as used in software testing. Observe that the feasible executions of a program Path condition is a logical formula over the symbolic inputs that encodes all branch decisions taken so far.

Generally speak- ing, a symbolic executor interprets a program with symbolic inputs, systematically enumerating execution paths induced by the symbolic inputs and the program's control flow. We propose symbolic execution for This paper describes a practical approach between these two extremes Each symbolic execution result may be equivalent to a large number of normal tests" Concolic testing overcomes these problems by combining concrete execution (i.e. This path condition characterizes the set of all concrete inputs that drive the program down the followed path. However, when a part of the path condition is infeasible for the SMT solver to handle, we substitute values from a test run of the program. Concolic Testing Dynamic Symbolic Execution Marco Probst Albert-Ludwigs-Universitt Freiburg January 25th, 2016 Marco Probst Concolic Testing 1 / 22. However, when a part of the path condition is infeasible for the SMT solver to handle, we substitute values from a test run of the program. Surprisingly, we can only find a few approaches to testing in the context of logic programming. 2.1 Symbolic execution At its core, every implementation of symbolic execution is constructed from a set of basic building blocks (see Figure1): Execution The program under test is executed, and the sys- If execution path depends on unknown, we fork symbolic executor at least, conceptually 5 Symbolic Execution Example 5 1.int a = , b = , c = ; 2.// symbolic The paper is a tutorial on symbolic execution and how it may be used in software testing and in particular the testing of commercial data-processing (DP) software. Dynamic Symbolic Execution [14], [15] (DSE) is a widely accepted and effective approach for automatic test data gener-ation. Unit tests are popular, but it is an art to write them in a way that specifies a program's behavior well and it is laborious to write enough of them to have confidence in the correctness of an implementation. At the other end of the spectrum, the most precise form of automatic code-driven test generation known today is dynamic test generation with symbolic execution. 2.2 Test Generation with Symbolic Execution.

Instead of supplying the normal inputs to a program (e.g. Instead of using concrete inputs, symbolic execution executes a program with symbolic inputs. AFL and libFuzzer. Skilled in Program Analysis and Verification Techniques such as Symbolic Execution, C, C++, CLPR, Logic Programming, Python.

ACM 1976] Analysis of programs with unspecied inputs -Execute a program on symbolic inputs Symbolic states represent sets of concrete states For each path, build a path condition -Condition on inputs - for the execution to follow that path The video shows how to use the klee_make_symbolic function to symbolise memory, how KLEE generates multiple test cases that explore different execution paths in the program and how we can use the KLEE ktest-tool to inspect the concrete values of the symbolic data. AddressSanitizer: A Fast Address Sanity Checker.

Overview 1 Code Example . The execution proceeds as in a normal execution except that values may be symbolic formulas over the input symbols. the strongest techniques is concrete{symbolic (concolic1) execution [19, 31]. A simple example of their difference: concurrency. We review, compare and discuss several approaches for representing programs by logic formulas, such as symbolic model checking, bounded model checking, verification-condition generation, and symbolic-execution-based test generation. In this paper, we introduce a systematic approach for dynamic testing that combines both concrete and symbolic execution. On the Danger of Coverage Directed Test Case Generation. symbolic execution is typically used in software testing to explore as many different program paths as possible in a given amount of time, and for each path to generate a set of concrete input values exercising it, and check for the presence of various kinds of errors including assertion violations, uncaught exceptions, security vulnerabilities, Second, Symbolic Analysis and Test Generation. 96 A System to Generate Test Data and Symbolically Execute Programs L. Clarke Computer Science Concolic execution explores a program by running it on concrete input values, for example x = 0 and u = 1.0, and at the same time using symbolic execution to collect the constraints of the followed program path. symbolic execution, a description of the three fundamental prob-lems, and a summary of existing well known techniques that ad-dress those problems.

A simple example of their difference: concurrency.

James C. King. testing) with symbolic execution.1 Symbolic execution is used to solve for inputs that lead along a certain path. ACM 1976] Analysis of programs with unspecied inputs -Execute a program on symbolic inputs Symbolic states represent sets of concrete states For each path, build a path condition -Condition on inputs - for the execution to follow that path Unlike concrete execution, where the taken path is determined by the input, in symbolic execution the program can take any feasible path.

Symbolic execution is a program analysis technique introduced in the 70s that has received renewed interest in recent years, due to algorithmic advances and increased availability of . ferential testing within a single symbolic execution engine; 3)A toolkit implementing our approach together with com-prehensive case studies on three symbolic execution enginesKLEE, CREST and FuzzBALLimplementing different styles of symbolic execution (e.g. Symbolic execution and program testing Commun. Symbolic state maps variables to symbolic values. symbolic execution [14, 26, 1, 13, 25, 2, 27, 8, 24] addresses the problem of poor test coverage. present a novel framework based on symbolic execution, for automated checking of such systems. It can be used for systematically testing a program and test input generation with high coverage. ACM , 19(7), 385-394 Published February 15, 1976 J. Symbolic execution King, CACM 1976. To support the verification, add to the language two statements: . Welcome to my web-page! Symbolic Execution King [Comm. In symbolic execution, a program is executed using symbolic variables in place of con-crete values for inputs. Each conditional expression in the program represents a constraint that determines an execu-tion path. Different flavors of the symbolic analysis of the software include, but are not limited to, concolic testing [10,11], symbolic execution [12, 13], and symbolic interpretation [14]. Symbolic execution [10, 22] is another classical technique for software testing and analysis. Instead of using concrete in-put, symbolic execution uses symbolic values as input and explores a program's execution space. Symbolic execution is a program analysis technique that was introduced in the 70s (e.g., see [14, 37, 76, 79, 103]). Dynamic execution of program Observe behavior Compare against expected behavior e.g. The collected constraints are J.C. King. Abstract: We present results for the "Impact Project Focus Area" on the topic of symbolic execution as used in software testing. The paper Symbolic execution and program testing of James C. King gives you a nice intro on symbolic execution topic; Slides from this Harvard course are useful to visualize symbolic execution with nice figures and examples; Dynamic Binary Analysis and Instrumentation Covering a function using a DSE approach by Jonathan Salwan. output or "do not crash" Marco Probst Concolic Testing 8 / 22. Symbolic execution is an approach that can help. Software testing is one of the most popular validation techniques in the software industry. Concolic testing overcomes these problems by combining concrete execution (i.e. We describe techniques for unit testing based on symbolic execution. I think symbolic execution can be used in many other interesting ways Next: Symbolic execution as Empirical studies tool Web application security checker Enhancement to abstraction-based static analysis Program synthesis tool All of these take advantage of sym exec strengths, and try to avoid drawbacks 7 Generally speak-ing, a symbolic executor interprets a program with symbolic inputs, systematically enumerating execution paths induced by the symbolic inputs and the program's control ow.

numbers) one supplies symbols represent- ing arbitrary values. Viewing symbolic execution as a kind of testing. Key idea: generalize testing by using unknown symbolic variables in evaluation Symbolic executor executes program, tracking symbolic state. Symbolic execution is a powerful technique for analyz-ing program behavior, nding bugs, and generating tests, but suffers from severely limited scalability: the largest pro-grams that can be symbolically executed today are on the order of thousands of lines of code. I did my Ph.D. and PostDoc at National University of Singapore (Class .

numbers) one supplies symbols representing arbitrary values. testing) with symbolic execution.1 Symbolic execution is used to solve for inputs that lead along a certain path. Symbolic execution . Symbolic execution is a powerful technique to systematically explore paths (possibly all) of a software program.

The execution proceeds as in a In symbolic execution, a pro-gram is executed using symbolic variables in place of con-crete values for inputs. It may be used in the generation of test data, in program proving, and in program reduction. A program, which is executed using actual data, results in the output of a series of values. Model checking can handle multi-thread systems because it is specified in the FSM provided as input, however, symbolic execution . 1 The tool that . 3: AddressSanitizer.

Introduction to Symbolic Execution In contrast to black box test data generation approaches, which generate test data for a program without considering AddressSanitizer Algorithm . K. Serebryany et al. Random Testing and Dynamic Symbolic Execution. This is despite the high promises that the symbolic execution technique engendered when it was first proposed as a method for automatic test data generation . a key goal of symbolic execution in the context of soft- ware testing is to explore as many different program paths as possible in a given amount of time, and for each path to (1) generate a set of concrete input values exercising that path, and (2) check for the presence of various kinds of errors including assertion violations, uncaught "Program testing and program proving can be considered as extreme alternatives. 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. Use symbolic execution to verify a use indicated function in the program.

The program is currently displayed in (GMT+02:00) Amsterdam, Berlin, Bern, Rome, . I am a Distinguished Engineer at Lacework . Symbolic execution: basic idea 8 Execute the program on symbolic values. This path condition characterizes the set of all . First, we dene a source to source translation to instrument a program, which enables standard model checkers to perform symbolic execution of the program.

symbolic execution and program testing

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