Custom execution environments in the BOINC middleware

Abstract. BOINC is a middleware that builds the largest grids on Earth out of commodity hardware offered by volunteers. Although BOINC has a large user base, it suffers from two fundamental limitations: first, it can only provide limited security to volunteer machines; second, creating large-scale projects is a formidable task only accessible to a few. Virtualization is a concept introduced many years ago, but its recent de-velopments in consumer hardware provide fertile ground for improvements in many applications. Virtualization is one of the forms of sand-boxing, where applications are confined to a closed environment, to prevent them from causing any harm to the hosting system. To provide the security that volunteers expect, but also to simplify the task of project creators, we present Libboincexec, a library that enables BOINC to use custom execution environments. These environments can include, but are not restricted to any well-known virtual machine, a simple fork() and exec(), or even secure shell commands.