Harden GitHub Actions Workflow - k3d.yml

[int-stepsecurity-advanced]

GitHub Token Permissions Are Not Set to Minimum in Workflow

Summary

The GitHub token permissions in your workflow file (.github/workflows/k3d.yml) exceed the minimum required. Reducing permissions to the minimum necessary enhances security by limiting the access scope of the token, thereby lowering the risk of accidental or malicious misuse.

Why This is Important

Using excessive permissions in GitHub workflows can expose your repository to potential security risks. The GitHub token grants access to repository resources, and any unnecessary permissions increase the likelihood of sensitive actions being performed without justification. By applying the principle of least privilege, you protect your repository from unintended data exposure and ensure that each job only has access to what it absolutely needs.

Evidence of Excessive Permissions

For more context, please refer to the build log from your recent workflow run, which highlights the permissions granted to the GitHub token that exceed the recommended minimum.

Suggested Fix

Below is the updated permissions configuration, which minimizes access for the GitHub token. Update your workflow file with this suggested configuration to resolve this issue:

```diff
  name: Set up Local Kubernetes with k3d and containerd
  on:
    workflow_dispatch:
+ permissions:
+   contents: read
  jobs:
    setup-k8s:
      runs-on: ubuntu-latest
      steps:
      - name: Harden Runner
        uses: step-security/harden-runner@v2
        with:
          egress-policy: block
          allowed-endpoints: >
            auth.docker.io:443
            dl-cdn.alpinelinux.org:443
            ghcr.io:443
            github.com:443
            objects.githubusercontent.com:443
            pkg-containers.githubusercontent.com:443
            production.cloudflare.docker.com:443
            raw.githubusercontent.com:443
            registry-1.docker.io:443
            
          
      - name: Checkout repository
        uses: actions/checkout@v3
      # Install k3d (lightweight wrapper to run K3s in Docker)
      - name: Install k3d
        run: |
          curl -s https://raw.githubusercontent.com/k3d-io/k3d/main/install.sh | bash
      # Create a Kubernetes cluster using k3d
      - name: Create k3d cluster
        run: |
          k3d --version
          k3d cluster create mycluster --wait --verbose
          k3d cluster list  # List the clusters to ensure it's up and running
      # Verify Kubernetes cluster is up and running
      - name: Verify connection to cluster
        run: kubectl get nodes
      - run: docker ps
      # Apply your Kubernetes deployment
      # Apply your Kubernetes deployment
      - name: Deploy app to local k8s cluster
        run: |
          kubectl apply -f k8s/deployment.yml  # Ensure your deployment YAML is in the k8s folder
          kubectl rollout status deployment/nginx-deployment  # Use the correct deployment name
      # Check pods using containerd runtime
      - name: Check pods running in containerd
        run: |
          kubectl get pods -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.containerStatuses[0].containerID}{"\n"}{end}'
      - name: Get nginx pod name
        id: getpod
        run: |
          POD_NAME=$(kubectl get pods -l app=nginx -o jsonpath="{.items[0].metadata.name}")
          echo "POD_NAME=${POD_NAME}"
          echo "::set-output name=podname::${POD_NAME}"
      - name: Check /etc/resolv.conf in curl-sidecar container
        run: |
          kubectl exec -it ${{ steps.getpod.outputs.podname }} -c curl-sidecar -- cat /etc/resolv.conf
      - name: Print k3s server logs
        run: |
           docker logs k3d-mycluster-server-0
           docker exec k3d-mycluster-server-0 cat /etc/resolv.conf
           docker inspect k3d-mycluster-server-0 | grep -i networkmode
      

Next Steps

Please review and update the workflow file with these minimum permissions. If additional permissions are necessary for certain steps, specify only those permissions explicitly.

For further guidance, refer to the GitHub documentation on fine-grained permissions.

Severity: High