A Secure Run Of An Untrusted Program Code In The Pivo System

PIVO (Programmer's Interactive Excercise Environment) is an interactive online practicing tool for algorithmical thinking and programming developed at the Faculty of Electrical Engineering, University of Ljubljana, Slovenia. It is used for independent study, excercising and examination in programming courses. Through the sistem, a student aquires a task, develops a solution in his/hers personal working environment and submits the source code to the server. The code is compiled, run and tested in real time. The submitted code can be incomplete and potentially harmful to the server. This paper proposes techniques for untrusted code sandboxing based on built-in Linux security mechanisms. Using the techiques, PIVO serves multiple users safely and fast. Among the students, the PIVO environment is well accepted, its impacts and positive study improvements are measurable already after only a few semesters of usage.