Sentry: A Binary-Level Interposition Mechanism for Trusted Kernel Extension
ABSTRACT Several commodity operating systems have used kernel extensions to extend or replace their functionalities. Generally, since the kernel extensions are executed in the same address space with the kernel, a mere fault in the extensions may lead the whole system to be corrupted. So naturally, studies on the kernel extension are mainly proposed with the goal of isolating extension faults from the system. However, previous schemes require the static analysis of the extension module and the modification of kernel source code. The goal of this paper is to remove such overhead stages. This paper proposes Sentry; a lightweight kernel subsystem that provides dependable execution environment for the kernel extensions. We show the efficiency of Sentry through practical implementation on Linux.
Full-textDOI: · Available from: Jaehyun Hwang, Jul 17, 2014
- SourceAvailable from: psu.edu
Article: On µ-Kernel Construction[Show abstract] [Hide abstract]
ABSTRACT: From a software-technology point of view, the µ-kernel concept is superior to large integrated kernels. On the other hand, it is widely believed that (a) µ-kernel based systems are inherently inefficient and (b) they are not sufficiently flexible. Contradictory to this belief, we show and support by documentary evidence that inefficiency and inflexibility of current µ-kernels is not inherited from the basic idea but mostly from overloading the kernel and/or from improper implementation. Based on functional reasons, we describe some concepts which must be implemented by a µ-kernel and illustrate their flexibility. Then, we analyze the performance critical points. We show what performance is achievable, that the efficiency is sufficient with respect to macro-kernels and why some published contradictory measurements are not evident. Furthermore, we describe some implementation techniques and illustrate why µ-kernels are inherently not portable, although they improve portability of the whole system.
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