HECTOR-V: A Heterogeneous CPU Architecture for a Secure RISC-V Execution Environment

Abstract

To ensure secure and trustworthy execution of applications, vendors frequently embed trusted execution environments into their systems. Here, applications are protected from adversaries, including a malicious operating system. TEEs are usually built by integrating protection mechanisms directly into the processor or by using dedicated external secure elements. However, both of these approaches only cover a narrow threat model resulting in limited security guarantees. Enclaves in the application processor typically provide weak isolation between the secure and non-secure domain, especially when considering side-channel attacks. Although secure elements do provide strong isolation, the slow communication interface to the application processor is exposed to adversaries and restricts the use cases. Independently of the used implementation approach, TEEs often lack the possibility to establish secure communication to external peripherals, and most operating systems executed inside TEEs do not provide state-of-the-art defense strategies, making them vulnerable against various attacks. We argue that TEEs implemented on the main application processor are insecure, especially when considering side-channel attacks. We demonstrate how a heterogeneous architecture can be utilized to realize a secure TEE design. We directly embed a processor into our architecture to provide strong isolation between the secure and non-secure domain. The tight coupling of TEE and REE enables HECTOR-V to provide mechanisms for establishing secure communication channels. We further introduce RISC-V Secure Co-Processor, a security-hardened processor tailored for TEEs. To secure applications executed inside the TEE, RVSCP provides control-flow integrity, rigorously restricts I/O accesses to certain execution states, and provides operating system services directly in hardware.

References in corpus (7)

• Software Grand Exposure: SGX Cache Attacks Are Practical
• ARMageddon: Cache Attacks on Mobile Devices
• Malware Guard Extension: Using SGX to Conceal Cache Attacks
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• TeeRex: Discovery and Exploitation of Memory Corruption Vulnerabilities in SGX Enclaves
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Cited by in corpus (6)

• A Survey on RISC-V Security: Hardware and Architecture
• Unleashing OpenTitan's Potential: a Silicon-Ready Embedded Secure Element for Root of Trust and Cryptographic Offloading
• MAMBO-V: Dynamic Side-Channel Leakage Analysis on RISC-V
• Attestation Mechanisms for Trusted Execution Environments Demystified
• Towards a Trusted Execution Environment via Reconfigurable FPGA
• T-Edge: Trusted Heterogeneous Edge Computing