Department of Computer Science, MSc Thesis Presentations, Henrik Niskanen

MetaPod: Hardened Mesh-Enforcement of Distributed Attested Pods

Author: Henrik Niskanen
Supervisor: Lachlan Gunn
Advisors: Huy Ngo, Merlijn Sebrechts

Abstract: This thesis addresses the problem of establishing trust in a microservice application whose services run under confidential computing. Each service runs in a hardware-protected virtual machine and can attest its own integrity to a remote party. In a public cloud the tenant not control or trust the infrastructure that orchestrates services, so proving one service at a time does not establish that the application is trustworthy. Existing architectures that attest several services at once bind them to a declaration of what may run, which an omitted or duplicated service satisfies.

We present MetaPod, a Kubernetes-native architecture built on Confidential Containers that combines a peer-to-peer attestation protocol to bind a deployment's composition into the attestation evidence of every service, and a proxy confining its traffic to that composition, entirely without modifying to existing application containers. Appraised against the composition the tenant declared, the resulting evidence exposes any alteration to the intended application structure and any unauthorised workload. The identities the protocol establishes are the credentials the services authenticate with, so nothing outside the attested composition can reach inside it, and a relying party can establish the trustworthiness of the application as a whole. 

We demonstrate the architecture by porting an existing seven service microservice application of to run under MetaPod without modifying its source code. Our evaluation shows that establishing trust is confined to a startup cost, and does not grow with the number of services, and that per-request latency is within a millisecond compared to a deployment running in Confidential Containers with an authenticated and encrypted service mesh.