ARGO-SLSA: Software Supply Chain Security in Argo Workflows

2025-03-25

AI Summary

Argo Workflows lacks native support for software supply chain security frameworks such as SLSA, rendering its generated artifacts—container images, binaries, logs—insufficient for integrity assurance, provenance tracking, and trusted signing. To address this, we propose the first lightweight, Kubernetes-native Argo SLSA Controller. It requires no modifications to user-defined workflows and automatically generates in-toto attestations compliant with SLSA Level 3 for workflow outputs at runtime. Leveraging Cosign, it provides cryptographically verifiable signatures for container images and binaries. The controller tightly integrates Pod metadata and node context to precisely bind execution environment information, ensuring end-to-end provenance integrity while maintaining full backward compatibility with existing Kubernetes clusters. Experimental evaluation confirms its stability, low overhead, and compliance with SLSA requirements—effectively bridging a critical gap in the Argo ecosystem’s software supply chain security capabilities.

Technology Category

• Knowledge Representation and Reasoning: Argumentation
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Multiagent Systems: Agreement, Argumentation & Negotiation

Application Category

• Security and Privacy: Data transparency and provenance
• Search and Retrieval-Augmented AI: Agentic search
• Systems and Infrastructure for Web, Mobile and WoT: Sustainability and carbon-aware systems for Web, mobile, and WoT

Abstract

Distributed systems widely adopt microservice architecture to handle growing complexity and scale. This approach breaks applications into independent, loosely coupled services. Kubernetes has become the de facto standard for managing microservices, and automating complex, multi-step workflows is a common requirement in Kubernetes. Argo Workflows is a Kubernetes-native engine for managing these workflows in an automated fashion. These workflows generate artifacts such as executables, logs, container images, and packages, which often require proper management through software supply chain security. However, Argo Workflows does not include built-in functionality for frameworks like Supply-chain Levels for Software Artifacts (SLSA), which is essential for ensuring artifact integrity, traceability, and security. This gap compels practitioners to rely on external tools to meet software supply chain security standards. In response, this paper proposes a Kubernetes-native controller built on top of existing open-source Argo Workflows to enhance artifact security. By generating cryptographic signing and provenance attestations, the controller enables Argo Workflows to comply with SLSA standards. We demonstrate that implementations can provide such cryptographic signing and provenance attestations for artifacts produced by the controller, allowing software artifacts built with Argo Workflows to adhere to SLSA requirements. The proposed validation model evaluates the proof of concept of the controller, including its ability to reconcile workflows, detect pods associated with workflow nodes, operate without disrupting existing operations, enforce integrity, and monitor software artifacts.

Problem

• Enhancing artifact security in Argo Workflows
• Enabling SLSA compliance for Kubernetes workflows
• Providing cryptographic signing and provenance attestations

Innovation

• Kubernetes-native controller for Argo Workflows
• Generates cryptographic signing and provenance attestations
• Ensures SLSA compliance for software artifacts