Add SLSA3 generators to release workflow

.github/workflows/release.yml

@@ -11,16 +11,22 @@ on:
         required: true
 
 permissions:
-  contents: write # needed to write releases
-  id-token: write # needed for keyless signing
-  packages: write # needed for ghcr access
+  contents: read
 
 env:
   CONTROLLER: ${{ github.event.repository.name }}
 
 jobs:
-  build-push:
+  release:
+    outputs:
+      hashes: ${{ steps.slsa.outputs.hashes }}
+      image_url: ${{ steps.slsa.outputs.image_url }}
+      image_digest: ${{ steps.slsa.outputs.image_digest }}
     runs-on: ubuntu-latest
+    permissions:
+      contents: write # for creating the GitHub release.
+      id-token: write # for creating OIDC tokens for signing.
+      packages: write # for pushing and signing container images.
     steps:
       - name: Checkout
         uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
@@ -61,6 +67,7 @@ jobs:
           tags: |
             type=raw,value=${{ steps.prep.outputs.VERSION }}
       - name: Publish images
+        id: build-push
         uses: docker/build-push-action@2eb1c1961a95fc15694676618e422e8ba1d63825 # v4.1.1
         with:
           sbom: true
@@ -72,32 +79,82 @@ jobs:
           platforms: linux/amd64,linux/arm/v7,linux/arm64
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-      - name: Check images
-        run: |
-          docker buildx imagetools inspect docker.io/fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.VERSION }}
-          docker buildx imagetools inspect ghcr.io/fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.VERSION }}
-          docker pull docker.io/fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.VERSION }}
-          docker pull ghcr.io/fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.VERSION }}
       - uses: sigstore/cosign-installer@dd6b2e2b610a11fd73dd187a43d57cc1394e35f9 # v3.0.5
       - name: Sign images
         env:
           COSIGN_EXPERIMENTAL: 1
         run: |
-          cosign sign --yes fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.VERSION }}
-          cosign sign --yes ghcr.io/fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.VERSION }}
+          cosign sign --yes fluxcd/${{ env.CONTROLLER }}@${{ steps.build-push.outputs.digest }}
+          cosign sign --yes ghcr.io/fluxcd/${{ env.CONTROLLER }}@${{ steps.build-push.outputs.digest }}
       - name: Generate release artifacts
         if: startsWith(github.ref, 'refs/tags/v')
         run: |
           mkdir -p config/release
           kustomize build ./config/crd > ./config/release/${{ env.CONTROLLER }}.crds.yaml
           kustomize build ./config/manager > ./config/release/${{ env.CONTROLLER }}.deployment.yaml
-          echo '[CHANGELOG](https://github.com/fluxcd/${{ env.CONTROLLER }}/blob/main/CHANGELOG.md)' > ./config/release/notes.md
       - uses: anchore/sbom-action/download-syft@4d571ad1038a9cc29d676154ef265ab8f9027042 # v0.14.2
       - name: Create release and SBOM
+        id: run-goreleaser
         if: startsWith(github.ref, 'refs/tags/v')
         uses: goreleaser/goreleaser-action@336e29918d653399e599bfca99fadc1d7ffbc9f7 # v4.3.0
         with:
           version: latest
-          args: release --release-notes=config/release/notes.md --rm-dist --skip-validate
+          args: release --clean --skip-validate
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Generate SLSA metadata
+        id: slsa
+        env:
+          ARTIFACTS: "${{ steps.run-goreleaser.outputs.artifacts }}"
+        run: |
+          hashes=$(echo $ARTIFACTS | jq --raw-output '.[] | {name, "digest": (.extra.Digest // .extra.Checksum)} | select(.digest) | {digest} + {name} | join("  ") | sub("^sha256:";"")' | base64 -w0)
+          echo "hashes=$hashes" >> $GITHUB_OUTPUT
+
+          image_url=fluxcd/${{ env.CONTROLLER }}:${{ steps.prep.outputs.version }}
+          echo "image_url=$image_url" >> $GITHUB_OUTPUT
+
+          image_digest=${{ steps.build-push.outputs.digest }}
+          echo "image_digest=$image_digest" >> $GITHUB_OUTPUT
+
+  release-provenance:
+    needs: [release]
+    permissions:
+      actions: read # for detecting the Github Actions environment.
+      id-token: write # for creating OIDC tokens for signing.
+      contents: write # for uploading attestations to GitHub releases.
+    if: startsWith(github.ref, 'refs/tags/v')
+    uses: slsa-framework/slsa-github-generator/.github/workflows/[email protected]
+    with:
+      provenance-name: "provenance.intoto.jsonl"
+      base64-subjects: "${{ needs.release.outputs.hashes }}"
+      upload-assets: true
+
+  dockerhub-provenance:
+    needs: [release]
+    permissions:
+      actions: read # for detecting the Github Actions environment.
+      id-token: write # for creating OIDC tokens for signing.
+      packages: write # for uploading attestations.
+    if: startsWith(github.ref, 'refs/tags/v')
+    uses: slsa-framework/slsa-github-generator/.github/workflows/[email protected]
+    with:
+      image: ${{ needs.release.outputs.image_url }}
+      digest: ${{ needs.release.outputs.image_digest }}
+      registry-username: fluxcdbot
+    secrets:
+      registry-password: ${{ secrets.DOCKER_FLUXCD_PASSWORD }}
+
+  ghcr-provenance:
+    needs: [release]
+    permissions:
+      actions: read # for detecting the Github Actions environment.
+      id-token: write # for creating OIDC tokens for signing.
+      packages: write # for uploading attestations.
+    if: startsWith(github.ref, 'refs/tags/v')
+    uses: slsa-framework/slsa-github-generator/.github/workflows/[email protected]
+    with:
+      image: ghcr.io/${{ needs.release.outputs.image_url }}
+      digest: ${{ needs.release.outputs.image_digest }}
+      registry-username: fluxcdbot
+    secrets:
+      registry-password: ${{ secrets.GHCR_TOKEN }}

.goreleaser.yaml

@@ -4,9 +4,26 @@ builds:
   - skip: true
 
 release:
-  prerelease: "true"
   extra_files:
     - glob: config/release/*.yaml
+  prerelease: "auto"
+  header: |
+    ## Changelog
+
+    [{{.Tag}} changelog](https://github.com/fluxcd/{{.ProjectName}}/blob/{{.Tag}}/CHANGELOG.md)
+  footer: |
+    ## Container images
+
+    - `docker.io/fluxcd/{{.ProjectName}}:{{.Tag}}`
+    - `ghcr.io/fluxcd/{{.ProjectName}}:{{.Tag}}`
+
+    Supported architectures: `linux/amd64`, `linux/arm64` and `linux/arm/v7`.
+
+    The container images are built on GitHub hosted runners and are signed with cosign and GitHub OIDC.
+    To verify the images and their provenance (SLSA level 3), please see the [security documentation](https://fluxcd.io/flux/security/).
+
+changelog:
+  skip: true
 
 checksum:
   extra_files: