image signing and provenance generation

.github/workflows/publish.yaml

@@ -12,9 +12,13 @@ env:
 jobs:
     paranoia-inception:
       runs-on: ubuntu-latest
+      outputs:
+        image: ${{ steps.build-and-push.outputs.image }}
+        digest: ${{ steps.build-and-push.outputs.digest }}
       permissions:
         contents: read
         packages: write
+        id-token: write # for creating OIDC tokens for signing.
       steps:
         - name: Log in to the Container registry
           uses: docker/login-action@f4ef78c080cd8ba55a85445d5b36e214a81df20a
@@ -32,6 +36,14 @@ jobs:
         - name: Set up Docker Buildx
           uses: docker/setup-buildx-action@v2
 
+        # Install the cosign tool except on PR
+        # https://github.com/sigstore/cosign-installer
+        - name: Install cosign
+          uses: sigstore/cosign-installer@204a51a57a74d190b284a0ce69b44bc37201f343 #v3.0.3
+          with:
+            cosign-release: 'v2.0.2'
+
+
         - name: Extract metadata (tags, labels) for Docker
           id: meta
           uses: docker/metadata-action@57396166ad8aefe6098280995947635806a0e6ea
@@ -57,6 +69,7 @@ jobs:
 
         - name: Build and push
           uses: docker/build-push-action@v3
+          id: build-and-push
           with:
             context: .
             platforms: linux/amd64,linux/arm64
@@ -65,3 +78,33 @@ jobs:
             labels: ${{ steps.meta.outputs.labels }}
             cache-from: type=gha
             cache-to: type=gha,mode=max
+
+        # Sign the resulting Docker image digest except on PRs.
+        # This will only write to the public Rekor transparency log when the Docker
+        # repository is public to avoid leaking data.  If you would like to publish
+        # transparency data even for private images, pass --force to cosign below.
+        # https://github.com/sigstore/cosign
+        - name: Sign the published Docker image
+          # This step uses the identity token to provision an ephemeral certificate
+          # against the sigstore community Fulcio instance.
+          env:
+            TAGS: ${{ steps.meta.outputs.tags }}
+            DIGEST: ${{ steps.build-and-push.outputs.digest }}
+          run: echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}
+
+    provenance-for-images:
+      needs: [paranoia-inception]
+      permissions:
+        actions: read # for detecting the Github Actions environment.
+        id-token: write # for creating OIDC tokens for signing.
+        packages: write # for uploading attestations.
+      uses: slsa-framework/slsa-github-generator/.github/workflows/generator_container_slsa3.yml@v1.6.0
+      with:
+        image: ghcr.io/${{ github.repository }}
+        # The image digest is used to prevent TOCTOU issues.
+        # This is an output of the docker/build-push-action
+        # See: https://github.com/slsa-framework/slsa-verifier#toctou-attacks
+        digest: ${{ needs.paranoia-inception.outputs.digest }}
+        registry-username: ${{ github.actor }}
+      secrets:
+        registry-password: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/release.yaml

@@ -40,6 +40,8 @@ jobs:
     needs:
       - build
     runs-on: ubuntu-latest
+    outputs:
+      hashes: ${{ steps.hash.outputs.hashes }}
     permissions:
       contents: write
     steps:
@@ -54,10 +56,26 @@ jobs:
           mv paranoia-linux-arm64/paranoia bin/paranoia-linux-arm64
           mkdir man
           mv man-pages/* man/
+      - name: Generate hashes
+        shell: bash
+        id: hash
+        run: |
+          echo "hashes=$(sha256sum bin/paranoia-darwin-amd64 bin/paranoia-darwin-arm64 bin/paranoia-linux-amd64 bin/paranoia-linux-arm64 | base64 -w0)" >> "$GITHUB_OUTPUT"
       - name: Release
         uses: softprops/action-gh-release@v1
         with:
           files: |
             LICENSE.txt
             bin/paranoia-*
             man/*
+
+  provenance-for-binaries:
+    needs:
+      - release 
+    permissions:
+      actions: read # Needed for detection of GitHub Actions environment.
+      id-token: write # Needed for provenance signing and ID.
+      contents: write # Needed for release uploads.
+    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_generic_slsa3.yml@v1.5.0
+    with:
+      base64-subjects: "${{ needs.release.outputs.hashes }}"