Norn: An SMT Solver for String Constraints

  • Parosh Aziz Abdulla
  • Mohamed Faouzi Atig
  • Yu-Fang Chen
  • Lukáš Holík
  • Ahmed Rezine
  • Philipp Rümmer
  • Jari StenmanEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9206)


We present version 1.0 of the Norn SMT solver for string constraints. Norn is a solver for an expressive constraint language, including word equations, length constraints, and regular membership queries. As a feature distinguishing Norn from other SMT solvers, Norn is a decision procedure under the assumption of a set of acyclicity conditions on word equations, without any restrictions on the use of regular membership.


Inference Rule Regular Expression Satisfying Assignment Length Constraint String Variable 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Abdulla, P.A., Atig, M.F., Chen, Y.-F., Hol\’ık, L., Rezine, A., Rümmer, P., Stenman, J.: String Constraints for Verification. In: Biere, A., Bloem, R. (eds.) CAV 2014. LNCS, vol. 8559, pp. 150–166. Springer, Heidelberg (2014) Google Scholar
  2. 2.
    Bjorner, N., Ganesh, V., Michel, R., Veanes, M.: Smt-lib sequences and regular expressions. In: Fontaine, P., Goel, A. (eds.) SMT 2012. EPiC Series, vol. 20, pp. 77–87. EasyChair (2013)Google Scholar
  3. 3.
    Griggio, A.: A practical approach to satisfiability modulo linear integer arithmetic. JSAT 8(1/2), 1–27 (2012)MathSciNetGoogle Scholar
  4. 4.
    Kausler, S., Sherman, E.: Evaluation of string constraint solvers in the context of symbolic execution. In: Crnkovic, I., Chechik, M., Grünbacher, P. (eds.) ACM/IEEE International Conference on Automated Software Engineering, ASE’2014, Vasteras, Sweden - 15–19 Sept 2014. pp. 259–270. ACM (2014).
  5. 5.
    Kiezun, A., Ganesh, V., Guo, P.J., Hooimeijer, P., Ernst, M.D.: HAMPI: A Solver for String Constraints. In: ISTA. pp. 105–116. ACM (2009)Google Scholar
  6. 6.
    Liang, T., Reynolds, A., Tinelli, C., Barrett, C., Deters, M.: A DPLL(T) theory solver for a theory of strings and regular expressions. In: Biere, A., Bloem, R. (eds.) CAV 2014. LNCS, vol. 8559, pp. 646–662. Springer, Heidelberg (2014) Google Scholar
  7. 7.
    Møller, A.: dk.brics.automaton - finite-state automata and regular expressions for Java (2010).
  8. 8.
    Nieuwenhuis, R., Oliveras, A., Tinelli, C.: Solving SAT and SAT modulo theories: from an abstract Davis-Putnam-Logemann-Loveland procedure to DPLL(T). J. ACM 53(6), 937–977 (2006)MathSciNetCrossRefGoogle Scholar
  9. 9.
    Rümmer, P., Hojjat, H., Kuncak, V.: Disjunctive interpolants for horn-clause verification. In: Sharygina, N., Veith, H. (eds.) CAV 2013. LNCS, vol. 8044, pp. 347–363. Springer, Heidelberg (2013) CrossRefGoogle Scholar
  10. 10.
    Saxena, P., Akhawe, D., Hanna, S., Mao, F., McCamant, S., Song, D.: A symbolic execution framework for JavaScript. In: IEEE Symposium on Security and Privacy. pp. 513–528. IEEE Computer Society (2010)Google Scholar
  11. 11.
    Saxena, P., Hanna, S., Poosankam, P., Song, D.: FLAX: Systematic discovery of client-side validation vulnerabilities in rich web applications. In: NDSS. The Internet Society (2010)Google Scholar
  12. 12.
    Trinh, M.T., Chu, D.H., Jaffar, J.: S3: A symbolic string solver for vulnerability detection in web applications. In: Ahn, G., Yung, M., Li, N. (eds.) CCS. pp. 1232–1243. ACM (2014)Google Scholar
  13. 13.
    Yu, F., Alkhalaf, M., Bultan, T.: Stranger: an automata-based string analysis tool for PHP. In: Esparza, J., Majumdar, R. (eds.) TACAS 2010. LNCS, vol. 6015, pp. 154–157. Springer, Heidelberg (2010) CrossRefGoogle Scholar
  14. 14.
    Zheng, Y., Zhang, X., Ganesh, V.: Z3-str: A Z3-based string solver for web application analysis. In: Meyer, B., Baresi, L., Mezini, M. (eds.) ESEC/FSE. pp. 114–124. ACM (2013)Google Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Parosh Aziz Abdulla
    • 1
  • Mohamed Faouzi Atig
    • 1
  • Yu-Fang Chen
    • 2
  • Lukáš Holík
    • 3
  • Ahmed Rezine
    • 4
  • Philipp Rümmer
    • 1
  • Jari Stenman
    • 1
    Email author
  1. 1.Department of Information TechnologyUppsala UniversityUppsalaSweden
  2. 2.Institute of Information ScienceAcademia SinicaTaipeiTaiwan
  3. 3.Faculty of Information TechnologyBrno University of TechnologyBrnoCzech Republic
  4. 4.Department of Computer and Information ScienceLinköping UniversityLinköpingSweden

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