Verify SLSA Provenance with Harness GitHub Actions

Harness GitHub Actions provide a seamless way to integrate Harness's Software Supply Chain Security (SCS) capabilities directly into GitHub workflows. You can use this GitHub Action to perform various supply chain security tasks. The Harness GitHub Action includes multiple sub-actions, each designed for specific tasks. This document focuses on the harness/github-actions/slsa-verification sub-action, which is used to generate an SBOM and attest it if needed.

The harness/github-actions/slsa-verification verifies the SLSA provenance attestation by pulling the .att file from the configured container registry. It uses the public key from the key pair that was used for signing the attestation to perform the verification.

info

Keys for attestation and verification should be generated using Cosign and stored in HashiCorp Vault. Currently, Harness SCS supports only HashiCorp Vault. Support for additional Key Management Systems (KMS) will be introduced in the near future.

Requirements

Here are the prerequisites for using the GitHub Action.

1. Harness Account: Ensure you have a Harness account with the SCS license enabled.

2. Harness Account Details: Save the following Harness account details, which are required for all sub-actions. It is recommended to securely store these values using GitHub Secrets.

Key	Value Example	Description	Required
HARNESS_ACCOUNT_URL	https://example.harness.io	The URL of your Harness account.	Yes
HARNESS_ACCOUNT_ID	ppdfedDDDL_dharzdPs_JtWT7g	The unique identifier for your Harness account.	Yes
HARNESS_ORG_ID	SCS	The identifier for your Harness organization.	Yes
HARNESS_PROJECT_ID	SCS_ORG	The identifier for your Harness project within the organization.	Yes
HARNESS_API_KEY	${{ secrets.SCS_API_KEY }}	The API key for authenticating with Harness. Create an API key using a Service Account (recommended) or a Personal Account , and then add the key to GitHub Actions Secrets with "HARNESS_API_KEY" as the key name.	Yes
VAULT_ADDR	https://myvault.example.com	The URL of your Vault	No

3. Security Keys: For attestation generation and verification, Key pair is required. The key should be generated using Cosign of type ecdsa-P256. Currently, HashiCorp Vault is supported for storing and retrieving the key. Additional Key Management Services (KMS) will be supported in the future.

Usage Example

- name: SLSA Verification
  uses: harness/github-actions/slsa-verification
  with:
    HARNESS_ACCOUNT_URL: https://myaccount.harness.io
    HARNESS_ACCOUNT_ID: my_account_id_9YpRharzPs
    HARNESS_ORG_ID: my_org_id_default
    HARNESS_PROJECT_ID: example_project_id
    HARNESS_API_KEY: ${{ secrets.API_KEY_SAVED_AS_GH_SECRET }}
    VAULT_ADDR: ${{ secrets.VAULT_URL }}
    TARGET: example_image:latest
    VERIFY: true
    KMS_KEY: path/to/your/key

Configuration

Make sure to include the required configurations from the Requirements section in your workflow. Below are the specific configurations for the slsa-verification sub-action.

Key	Value Example	Description	Required
TARGET	example_image:latest	The target artifact (Docker image) for which SLSA provenance verification is performed.	Yes
VERIFY	true or false	Boolean flag to determine if verification is required.	Yes
KMS_KEY	path/to/your/key	Path to the public key used for verifying the attestation.	No

Sample workflow

Here's a sample workflow using the harness/github-actions/slsa-verification

name: SLSA Provenance Verification Workflow

on:
  push:
    branches:
      - main

jobs:
  slsa-verification-job:
    runs-on: self-hosted

    env:
      HARNESS_ACCOUNT_URL: 'https://myaccount.harness.io'
      HARNESS_ACCOUNT_ID: '_myaccount_rzPs_JtWT7g'
      HARNESS_ORG_ID: 'SCS'
      HARNESS_PROJECT_ID: 'SCS_ID'
      HARNESS_API_KEY: ${{ secrets.SCS_API_KEY }}
      VAULT_ADDR: ${{ secrets.VAULT_URL }}

    steps:
      # Step 1: Checkout the main repository
      - name: Checkout Main Repository
        uses: actions/checkout@v3

      # Step 2: Log in to Docker Hub
      - name: Log in to Docker Hub
        uses: docker/login-action@v2
        with:
          username: ${{ secrets.DOCKER_USERNAME }}
          password: ${{ secrets.DOCKER_PASSWORD }}

      # Step 3: Build and Tag Docker Image
      - name: Build and Tag Docker Image
        run: |
          docker build -t harness/github-service:latest -f ./stable/alpine/Dockerfile .
          echo "Docker image built and tagged as harness/github-service:latest."

      # Step 4: Push Docker Image to Docker Hub
      - name: Push Docker Image
        run: |
          docker push harness/github-service:latest
          echo "Docker image pushed to Docker Hub."

      # Step 5: Log in to Vault
      - name: Log in to Vault
        uses: hashicorp/vault-action@v2
        with:
          url: ${{ secrets.VAULT_URL }}
          method: token
          token: ${{ secrets.VAULT_TOKEN }}

      # Step 6: Run SLSA Verification
      - name: Run SLSA Verification Action
        uses: harness/github-actions/slsa-verification
        with:
          TARGET: 'harness/github-service:latest'
          VERIFY: true
          KMS_KEY: 'cosign'