Integer overflow is a common vulnerability in Ethereum Smart Contracts(ESCs)and often causes huge economic losses.Smart contracts cannot be changed once it is deployed on the blockchain and thus demand further testing...Integer overflow is a common vulnerability in Ethereum Smart Contracts(ESCs)and often causes huge economic losses.Smart contracts cannot be changed once it is deployed on the blockchain and thus demand further testing.Mutation testing is a fault-based testing method that can effectively improve the sufficiency of a test for smart contracts.However,existing methods cannot efficiently perform mutation testing specifically for integer overflow in ESCs.Therefore,by analyzing integer overflow in ESCs,we propose five special mutation operators to address such vulnerability in terms of detecting sufficiency in ESC testing.An empirical study on 40 open-source ESCs is conducted to evaluate the effectiveness of the proposed mutation operators.Results show that(1)our proposed mutation operators can reproduce all 179 integer overflow vulnerabilities in 40 smart contracts,and the generated mutants have high compilation pass rate and integer overflow vulnerability generation rate;moreover,(2)the generated mutants can find the shortcomings of existing testing methods for integer overflow vulnerability,thereby providing effective support to improve the sufficiency of the test.展开更多
A simplified integer overflow detection method based on path relaxation is described for avoiding buffer overflow triggered by integer overflow. When the integer overflow refers to the size of the buffer allocated dyn...A simplified integer overflow detection method based on path relaxation is described for avoiding buffer overflow triggered by integer overflow. When the integer overflow refers to the size of the buffer allocated dynamically, this kind of integer overflow is most likely to trigger buffer overflow. Based on this discovery, through lightly static program analysis, the solution traces the key variables referring to the size of a buffer allocated dynamically and it maintains the upper bound and lower bound of these variables. After the constraint information of these traced variables is inserted into the original program, this method tests the program with test cases through path relaxation, which means that it not only reports the errors revealed by the current runtime value of traced variables contained in the test case, but it also examines the errors possibly occurring under the same execution path with all the possible values of the traced variables. The effectiveness of this method is demonstrated in a case study. Compared with the traditional buffer overflow detection methods, this method reduces the burden of detection and improves efficiency.展开更多
This paper presents a high-quality very large scale integration （VLSI） global router in X-architecture, called XGRouter, that heavily relies on integer linear pro- gramming （ILP） techniques, partition strategy and...This paper presents a high-quality very large scale integration （VLSI） global router in X-architecture, called XGRouter, that heavily relies on integer linear pro- gramming （ILP） techniques, partition strategy and particle swarm optimization （PSO）. A new ILP formulation, which can achieve more uniform routing solution than other formu- lations and can be effectively solved by the proposed PSO is proposed. To effectively use the new ILP formulation, a partition strategy that decomposes a large-sized problem into some small-sized sub-problems is adopted and the routing re- gion is extended progressively from the most congested re- git）n. In the post-processing stage of XGRouter, maze rout- ing based on new routing edge cost is designed to further optimize the total wire length and mantain the congestion uniformity. To our best knowledge, XGRouter is the first work to use a concurrent algorithm to solve the global rout- ing problem in X-architecture. Experimental results show that XGRouter can produce solutions of higher quality than other global routers. And, like several state-of-the-art global touters, XGRouter has no overflow.展开更多
LDPC码分层译码算法在进行整数量化操作时,存储单元的限制会导致译码信息的溢出。本文系统分析了溢出错误的原因,并提出了两种改进的分层译码方案,错误部分消除方案(partially eliminating errors scheme,PEES)和不同比特量化方案(diffe...LDPC码分层译码算法在进行整数量化操作时,存储单元的限制会导致译码信息的溢出。本文系统分析了溢出错误的原因,并提出了两种改进的分层译码方案,错误部分消除方案(partially eliminating errors scheme,PEES)和不同比特量化方案(different bit quantization scheme,DBQS)。两种改进方案分别从消除部分错误和避免溢出错误的角度来改进译码性能,且硬件实现时只需增加一定数量的加法器和移位操作。通过对不同码长、不同量化比特的LDPC码进行仿真,结果表明,2种方案均有效地抑制了溢出错误,与基于全精度浮点数运算的修正算法相比,在误码率为1.0×10-4时,分别仅有约1 d B和1.8 d B的性能损耗。展开更多
Integer overflow vulnerability will cause buffer overflow. The research on the relationship between them will help us to detect integer overflow vulnerability. We present a dynamic analysis methods RICB （Run-time Int...Integer overflow vulnerability will cause buffer overflow. The research on the relationship between them will help us to detect integer overflow vulnerability. We present a dynamic analysis methods RICB （Run-time Integer Checking via Buffer overflow）. Our approach includes decompile execute file to assembly language; debug the execute file step into and step out; locate the overflow points and checking buffer overflow caused by integer overflow. We have implemented our approach in three buffer overflow types： format string overflow, stack overflow and heap overflow. Experiments results show that our approach is effective and efficient. We have detected more than 5 known integer overflow vulnerabilities via buffer overflow.展开更多
基金supported by National Key R&D Program of China(No.2018YFB1403400)the National Natural Science Foundation of China(No.61702544)+1 种基金Natural Science Foundation of Jiangsu Province,China(Nos.BK20160769 and BK20141072)China Postdoctoral Science Foundation(No.2016M603031)。
文摘Integer overflow is a common vulnerability in Ethereum Smart Contracts(ESCs)and often causes huge economic losses.Smart contracts cannot be changed once it is deployed on the blockchain and thus demand further testing.Mutation testing is a fault-based testing method that can effectively improve the sufficiency of a test for smart contracts.However,existing methods cannot efficiently perform mutation testing specifically for integer overflow in ESCs.Therefore,by analyzing integer overflow in ESCs,we propose five special mutation operators to address such vulnerability in terms of detecting sufficiency in ESC testing.An empirical study on 40 open-source ESCs is conducted to evaluate the effectiveness of the proposed mutation operators.Results show that(1)our proposed mutation operators can reproduce all 179 integer overflow vulnerabilities in 40 smart contracts,and the generated mutants have high compilation pass rate and integer overflow vulnerability generation rate;moreover,(2)the generated mutants can find the shortcomings of existing testing methods for integer overflow vulnerability,thereby providing effective support to improve the sufficiency of the test.
基金The National Natural Science Foundation of China (No.60873050,60703086)the Opening Foundation of State Key Laboratory of Software Engineering in Wuhan University (No.SKLSE20080717)
文摘A simplified integer overflow detection method based on path relaxation is described for avoiding buffer overflow triggered by integer overflow. When the integer overflow refers to the size of the buffer allocated dynamically, this kind of integer overflow is most likely to trigger buffer overflow. Based on this discovery, through lightly static program analysis, the solution traces the key variables referring to the size of a buffer allocated dynamically and it maintains the upper bound and lower bound of these variables. After the constraint information of these traced variables is inserted into the original program, this method tests the program with test cases through path relaxation, which means that it not only reports the errors revealed by the current runtime value of traced variables contained in the test case, but it also examines the errors possibly occurring under the same execution path with all the possible values of the traced variables. The effectiveness of this method is demonstrated in a case study. Compared with the traditional buffer overflow detection methods, this method reduces the burden of detection and improves efficiency.
文摘This paper presents a high-quality very large scale integration （VLSI） global router in X-architecture, called XGRouter, that heavily relies on integer linear pro- gramming （ILP） techniques, partition strategy and particle swarm optimization （PSO）. A new ILP formulation, which can achieve more uniform routing solution than other formu- lations and can be effectively solved by the proposed PSO is proposed. To effectively use the new ILP formulation, a partition strategy that decomposes a large-sized problem into some small-sized sub-problems is adopted and the routing re- gion is extended progressively from the most congested re- git）n. In the post-processing stage of XGRouter, maze rout- ing based on new routing edge cost is designed to further optimize the total wire length and mantain the congestion uniformity. To our best knowledge, XGRouter is the first work to use a concurrent algorithm to solve the global rout- ing problem in X-architecture. Experimental results show that XGRouter can produce solutions of higher quality than other global routers. And, like several state-of-the-art global touters, XGRouter has no overflow.
文摘LDPC码分层译码算法在进行整数量化操作时,存储单元的限制会导致译码信息的溢出。本文系统分析了溢出错误的原因,并提出了两种改进的分层译码方案,错误部分消除方案(partially eliminating errors scheme,PEES)和不同比特量化方案(different bit quantization scheme,DBQS)。两种改进方案分别从消除部分错误和避免溢出错误的角度来改进译码性能,且硬件实现时只需增加一定数量的加法器和移位操作。通过对不同码长、不同量化比特的LDPC码进行仿真,结果表明,2种方案均有效地抑制了溢出错误,与基于全精度浮点数运算的修正算法相比,在误码率为1.0×10-4时,分别仅有约1 d B和1.8 d B的性能损耗。
基金Supported by the National Natural Science Foundation of China （60903188）, Shanghai Education Commission Innovation Foundation （11YZ192） and World Expo Science and Technology Special Fund of Shanghai Science and Technology Commission （08dz0580202）.
文摘Integer overflow vulnerability will cause buffer overflow. The research on the relationship between them will help us to detect integer overflow vulnerability. We present a dynamic analysis methods RICB （Run-time Integer Checking via Buffer overflow）. Our approach includes decompile execute file to assembly language; debug the execute file step into and step out; locate the overflow points and checking buffer overflow caused by integer overflow. We have implemented our approach in three buffer overflow types： format string overflow, stack overflow and heap overflow. Experiments results show that our approach is effective and efficient. We have detected more than 5 known integer overflow vulnerabilities via buffer overflow.
