electronics Article A Hardware Platform for Ensuring OS Kernel Integrity on RISC-V † Donghyun Kwon 1, Dongil Hwang 2,*,‡ and Yunheung Paek 2,*,‡ 1 School of Computer Science and Engineering, Pusan National University, Busan 46241, Korea ;
[email protected] 2 Department of Electrical and Computer Engineering (ECE) and Inter-University Semiconductor Research Center (ISRC), Seoul National University, Seoul 08826, Korea * Correspondence:
[email protected] (D.H.);
[email protected] (Y.P.); Tel.: +82-2-880-1742 (Y.P.) † This paper is an extended version of our paper published in Design, Automation and Test in Europe Conference & Exhibition (DATE) 2019. ‡ As corresponding authors, these authors contributed equally to this work. Abstract: The OS kernel is typically preassumed as a trusted computing base in most computing systems. However, it also implies that once an attacker takes control of the OS kernel, the attacker can seize the entire system. Because of such security importance of the OS kernel, many works have proposed security solutions for the OS kernel using an external hardware module located outside the processor. By doing this, these works can realize the physical isolation of security solutions from the OS kernel running in the processor, but they cannot access the inner state of the processor, which attackers can manipulate. Thus, they elaborated several methods to overcome such limited capability of external hardware. However, those methods usually come with several side effects, such as high-performance overhead, kernel code modifications, and/or excessively complicated hardware designs. In this paper, we introduce RiskiM, a new hardware-based monitoring platform to ensure kernel integrity from outside the host system.