helm-external-secrets/.github/actions/sign/action.yml

name: 'Provenance / SBOM / Sign'

description: 'Creates SBOM & provenance files and signs the image'

inputs:
  image-name:
    description: "name of the image"
    required: true
    default: ''
  image-tag:
    description: "image tag"
    required: true
    default: ""
  GHCR_USERNAME:
    description: "ghcr username"
    required: true
  GHCR_TOKEN:
    description: "ghcr token"
    required: true
  GITHUB_TOKEN:
    description: "gh token"
    required: true

runs:
  using: "composite"

  steps:

    - name: Install cosign
      uses: sigstore/cosign-installer@v2
      with:
        cosign-release: v1.13.6

    - name: Install Syft
      uses: anchore/sbom-action/download-syft@v0.7.0

    - name: Check Cosign install
      shell: bash
      run: cosign version

    - name: Login to ghcr.io
      uses: docker/login-action@v1.14.1
      with:
        registry: ghcr.io
        username: ${{ inputs.GHCR_USERNAME }}
        password: ${{ inputs.GHCR_TOKEN }}

    - name: Setup Go
      uses: actions/setup-go@v3
      with:
        go-version-file: "go.mod"

    - name: Set up crane
      shell: bash
      run: go install github.com/google/go-containerregistry/cmd/crane@v0.11.0

    - name: Get docker image tag
      id: container_info
      shell: bash
      run: echo "digest=$(crane digest ${{ inputs.image-name }}:${{ inputs.image-tag }})" >> $GITHUB_OUTPUT

    - name: Sign image
      shell: bash
      env:
        COSIGN_EXPERIMENTAL: "1"
      run: cosign sign -a GITHUB_ACTOR=${{ github.triggering_actor }} "${{ inputs.image-name }}@${{ steps.container_info.outputs.digest }}"

    - name: Attach SBOM to image
      shell: bash
      id: sbom
      env:
        COSIGN_EXPERIMENTAL: "1"
      run: |
        syft "${{ inputs.image-name }}@${{ steps.container_info.outputs.digest }}" -o spdx-json=sbom.${{ inputs.image-tag }}.spdx.json
        cosign attest --predicate sbom.${{ inputs.image-tag }}.spdx.json --type spdx "${{ inputs.image-name }}@${{ steps.container_info.outputs.digest }}"
        cosign verify-attestation --type spdx ${{ inputs.image-name }}@${{ steps.container_info.outputs.digest }} | jq '.payload |= @base64d | .payload | fromjson'

    - name: Generate provenance
      uses: philips-labs/slsa-provenance-action@v0.7.2
      with:
        command: generate
        subcommand: container
        arguments: --repository "${{ inputs.image-name }}" --output-path provenance.${{ inputs.image-tag }}.intoto.jsonl --digest "${{ steps.container_info.outputs.digest }}" --tags "${{ inputs.image-tag }}"
      env:
        COSIGN_EXPERIMENTAL: "0"
        GITHUB_TOKEN: "${{ inputs.GITHUB_TOKEN }}"

    - name: Attach provenance
      shell: bash
      id: provenance
      env:
        COSIGN_EXPERIMENTAL: "1"
      run: |
        jq '.predicate' provenance.${{ inputs.image-tag }}.intoto.jsonl > provenance-predicate.att
        cosign attest --predicate provenance-predicate.att --type slsaprovenance "${{ inputs.image-name }}@${{ steps.container_info.outputs.digest }}"
        cosign verify-attestation --type slsaprovenance ${{ inputs.image-name }}@${{ steps.container_info.outputs.digest }}