基于程序语义分析的网络协议测试关键技术研究

发布时间：2018-02-10 11:48

本文关键词： 网络协议测试结构化分析污点传播动态测试用例生成增量式快照　出处：《国防科学技术大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着计算机网络的不断发展和各种接入互联网终端的广泛使用,网络和人们的生产生活关系日益紧密,因而网络安全也受到更加广泛的关注。网络协议是网络应用程序功能逻辑的核心,然而网络协议缺陷广泛存在,像“心血”、“毒液”等网络协议缺陷导致了整个互联网范围的安全危机。因而对于网络协议进行高效测试的重要性不言而喻。对网络应用程序进行测试,关键就在于对其协议一致性进行检验,即检验协议的实现和协议设计规范之间的一致性。但是网络协议测试复杂,覆盖协议处理程序的所有分支是一个组合爆炸问题,而且进行测试的测试用例必须符合网络协议的报文格式规范。另一方面,已有的协议测试方法,如形式化验证、模糊测试和基于动态测试用例生成的协议测试方法存在不足。形式化验证中,我们很难确保推理得到的协议实现模型的准确性;模糊测试在生成测试用例时具有很大程度的盲目性;而已有的基于动态测试用例生成的方法存在对操作系统函数调用等信息的依赖等问题,因而跨平台适用性不好。此外,由于协议测试中需要对协议处理程序的每个分支或协议状态进行反复测试,所以需要频繁地进行回退,同时就需要对协议处理程序执行的内存和磁盘信息记录下来。而已有的测试方法中,在对协议执行状态进行回放和重复测试时,执行状态的存储和恢复效率低,严重影响了自动化协议测试的效率。本文提出并实现了一种基于程序语义分析的协议测试方法,避免了已有系统对操作系统平台的依赖性。通过增量式快照文件系统大幅度提升了协议状态的存储和恢复效率,提升了网络协议自动化测试性能。本文主要的工作内容包括以下四点:1)采用结构化分析的方法对网络协议处理程序进行分析,得到程序底层的基本语义信息。通过不同的控制结构与报文字段之间的绑定分析,实现对协议报文的分割和语义推断,并且实现对网络协议报文格式的重构。在此基础上通过污点传播收集了与报文污点相关的控制条件约束,从而实现动态测试用例的生成和协议测试;2)将动态污点传播技术扩展到多个协议执行实体,通过考察正常协议交互时的污点传播关系,在协议测试中,检测异常的协议执行实体间污点传播关系,发现信息泄露等类型的网络协议缺陷;3)设计并实现了一套增量式快照文件系统,以分布式Key-Value数据库作为文件系统底层存储引擎,将协议执行状态快照所采用的层次化数据模型高效映射到Key-Value数据模型,采用基于线段树数据结构的优化方法,提升了协议状态存储和恢复的效率。该文件系统大幅度提升了测试平台自动化协议测试的效率;4)针对网络协议测试的特点,通过以上技术构造了一个基于程序语义分析的网络协议测试平台Pro Test,我们将该平台运用于测试真实的网络协议,发现了已有协议中存在的缺陷,验证了方法的有效性。
[Abstract]:With the wide use of computer network development and various Internet access terminals, network and people's production and life of the increasingly close relationship, so the network security has also been more and more attention. The network protocol is the core network function of application logic, but the network protocol defects exist widely, like "blood", "poison defects" and other network the agreement led to the security crisis of the whole range of Internet. Therefore, it is self-evident importance of testing for network protocol. To test the network application, the key is to test the protocol conformance test, consistency between protocol implementation and protocol specification. But the network protocol testing complex, covering all branches of protocol processing the program is a combinatorial explosion problem, report and test case test case must comply with the network protocol Type specification. On the other hand, the test method of existing protocols, such as formal verification, testing and test method of fuzzy dynamic test generation protocol based on shortcomings. Formal verification, it is difficult to ensure the accuracy of the protocol implementation model reasoning; fuzzy test has certain blindness in the generation of test cases but the existing method; dynamic test generation based on operating system function calls and other information on other issues, so the cross platform applicability is not good. In addition, due to the need for a protocol handler in protocol testing protocol of each branch or state of repeated testing, so we need to frequently back, but you need the program the execution of memory and disk information recorded on the protocol processing. And the existing testing methods, in the execution state for playback and repeat the test of protocol, implementation The state of the storage and recovery efficiency is low, which seriously affects the efficiency of automated testing. This paper presents the design and implementation of a test program protocol based on semantic analysis method, avoids the dependence on the operating system platform of the existing system. Through the incremental snapshot file system greatly enhance the protocol state storage and recovery efficiency, enhance the network protocol testing automation performance. In this paper, the main contents include the following four points: 1) uses a structured analysis method for network protocol processing procedures for analysis, get the basic semantic information underlying information. Through the program control structure and message field different binding analysis, segmentation and semantic inference on the protocol message, and to realize the reconstruction of network protocol packet format. On the basis of collecting taint propagation control conditions associated with the message from the spot constraints. The generation and dynamic protocol test case; 2) dynamic taint propagation technique is extended to multiple protocol execution entity, through the relationship between the normal taint propagation protocol interaction, in protocol testing, protocol anomaly detection execution entity taint propagation, defect information leaks and other types of network protocols; 3) the design and implementation of an incremental snapshot file system, a distributed Key-Value database as the underlying file system storage engine, the efficient mapping hierarchical data model of protocol execution state snapshot is taken to the Key-Value data model, the optimization method of segment tree data structure based on the improved protocol state storage and recovery efficiency of the file. The system can greatly improve the efficiency of automated test platform of protocol testing; 4) according to the characteristics of network protocol test, through the above technology to construct a Pro Test, a network protocol testing platform based on program semantic analysis, is applied to test real network protocols. We find the defects in existing protocols, and verify the effectiveness of the method.

【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TP393.06

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