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Wed 20 Jan 2016 14:45 - 15:10 at Grand Bay North - Track 1: Decision Procedures Chair(s): Loris D'Antoni

We study the fundamental issue of decidability of satisfiability over string logics with concatenations and finite-state transducers as atomic operations. Although restricting to one type of operations yields decidability, little is known about the decidability of their combined theory, which is especially relevant when analysing security vulnerabilities of dynamic web pages in a more realistic browser model. On the one hand, word equations (string logic with concatenations) cannot precisely capture sanitisation functions (e.g. htmlescape) and implicit browser transductions (e.g. innerHTML mutations). On the other hand, transducers suffer from the reverse problem of being able to model sanitisation functions and browser transductions, but not string concatenations. Naively combining word equations and transducers easily leads to an undecidable logic. Our main contribution is to show that the straight-line fragment of the logic is decidable (complexity ranges from PSPACE to EXPSPACE). The fragment can express the program logics of straight-line string-manipulating programs with concatenations and transductions as atomic operations, which arise when performing bounded model checking or dynamic symbolic executions. We demonstrate that the logic can naturally express constraints required for analysing mutation XSS in web applications. Finally, we show that the logic remains decidable in the presence of length, letter-counting, regular, and indexOf constraints.

Wed 20 Jan
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14:20 - 16:00: Research Papers - Track 1: Decision Procedures at Grand Bay North
Chair(s): Loris D'AntoniUniversity of Pennsylvania
POPL-2016-papers14:20 - 14:45
Xin ZhangGeorgia Tech, Ravi MangalGeorgia Institute of Technology, Aditya NoriMicrosoft Research, UK, Mayur NaikGeorgia Tech
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POPL-2016-papers14:45 - 15:10
Anthony Widjaja LinYale-NUS College, Singapore, Pablo BarceloUniversity of Chile, Chile
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POPL-2016-papers15:10 - 15:35
Luca CardelliMicrosoft Research and University of Oxford, Mirco TribastoneIMT Institute for Advanced Studies Lucca, Italy, Max TschaikowskiIMT Institute for Advanced Studies Lucca, Italy, Andrea VandinIMT Institute for Advanced Studies Lucca, Italy
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POPL-2016-papers15:35 - 16:00
Matthew HagueRoyal Holloway University of London, UK, Jonathan KochemsDepartment of Computer Science, University of Oxford, C.-H. Luke OngUniversity of Oxford, UK
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