SmartNIC enforces safe access control for remote hardware resources
SADRA: Sound Capability-based Access Control System for Resource-Disaggregated Architectures
Cryptography and Security
Summary
Computers can now share parts like memory and accelerators across a network rather than being stuck inside one machine. This creates security challenges because the usual local checks can be bypassed if the host computer is compromised. The authors studied previous methods and found none solved all key problems. They built SADRA, a system where a special network card, isolated from the host, independently verifies each request at both the user’s computer and the resource itself, preventing unauthorized access even if some parts are outdated or compromised. Their tests show this works efficiently at high network speeds without slowing things down.
What this means in practice
- •For data center operators: Securely manage and enforce access rights to disaggregated memory and accelerators in large-scale data centers with untrusted hosts.
- •For network hardware engineers: Develop SmartNIC-based security features that independently verify and enforce capability-based permissions in distributed resource setups.
Authors
Hamed Rasifard, Amir Farahani Khojasteh, Hamed Nemati, Michael Backes
Abstract
Resource disaggregation separates memory and accelerators from compute nodes and makes them remotely accessible. This improves resource sharing, but also removes the local kernel from the resource-access path. Under an untrusted host, compromised host software may use stale authority, exceed delegated authority, or reuse authority provisioned for another process. Prior work identifies capability-based access control as well suited to these architectures. Our systematization of twenty-two prior capability systems finds that none combines host-independent validation of process authority, authoritative enforcement at the resource, and revocation that remains effective while remote authorization state is stale. We present SADRA, a distributed capability-based access-control system for resource-disaggregated architectures. SmartNIC hardware isolated from host software independently checks every inter-node request at two points, first at the compute node against the requesting process's authority and again at the resource against the current authoritative access state. Linked process, compute, and resource capabilities allow these checks to use local state without coordination on the access path. When distributed authority is revoked, SADRA denies subsequent dependent accesses at the resource without waiting for remote nodes to update, while stale capability state is reclaimed separately. We prove capability safety, authority safety, revocation soundness, and strong isolation for a formal architectural model, and model-check the formalization with SPIN. Our FPGA SmartNIC prototype sustains 89.5 Gbit/s aggregate throughput, within run-to-run variation of a non-enforcing baseline that peaks at 90--91 Gbit/s. Cleanup of a 128-capability subtree completes in 528 ns, while access denial does not depend on completion of that cleanup.