Portable resource control in Java

Abstract

Preventing abusive resource consumption is indispensable for all kinds of systems that execute untrusted mobile coee, such as mobile object sytems, extensible web servers, and web browsers. To implement the required defense mechanisms, some support for resource control must be available: accounting and limiting the usage of physical resources like CPU and memory, and of logical resources like threads. Java is the predominant implementation language for the kind of systems envisaged here, even though resource control is a missing feature on standard Java platforms. This paper describes the model and implementation mechanisms underlying the new resource-aware version of the J-SEAL2 mobile object kernel. Our fundamental objective is to achieve complete portability, and our approach is therefore based on Java bytecode transformations. Whereas resource control may be targeted towards the provision of quality of service or of usage-based billing, the focus of this paper is on security, and more specificlly on prevention of denial-of-service attacks orginating from hostile or poorly implemented mobile code.