ADR-0139: Releases are attested with GitHub artifact attestations, and pull requests scan the image

• Status: accepted
• Date: 2026-09-30
• Deciders: Mahdi Amirabdollahi
• Change: openspec/changes/06-supply-chain-security
• Amends: ADR-0042 — attestation is no longer deferred; ADR-0102 — the Central artifacts are attested

Context

A release pushes a multi-arch image to Docker Hub, a runnable jar to the GitHub release, the plugin API to Maven Central (GPG-signed) and the plugin SDK to npm (with npm provenance). Nobody could check that an image or jar came from this repository's pipeline, there was no SBOM, and the image was never scanned. ADR-0042 turned buildkit's SBOM and provenance off because they add unknown/unknown entries to the tag's platform list on Docker Hub, and deferred attestation until there were verifiers.

Decision

• Every released artifact is attested with actions/attest, keyless: a Sigstore bundle signed with a short-lived certificate for sudoitir/artemis-studio/.github/workflows/ci.yml. The image and the jar get SLSA provenance and a CycloneDX SBOM attestation; the jar, sources, javadoc and pom deployed to Central get SLSA provenance. The check is gh attestation verify <artifact> --repo sudoitir/artemis-studio --signer-workflow sudoitir/artemis-studio/.github/workflows/ci.yml.
• Image attestations are pushed to Docker Hub as OCI referrers, next to the image and outside its platform list. Buildkit's own provenance and sbom stay off.
• SBOMs are CycloneDX JSON from Syft, one for the image and one for the jar, attached to the GitHub release with the jar's provenance bundle (.intoto.jsonl).
• The release job verifies what it published with the documented command, so a broken verification path fails the release instead of reaching users.
• Pull requests scan the image with Grype, run from its image pinned by digest. One run reports every finding; a second, --only-fixed --fail-on high, fails the build on a fixable high or critical and names the fixed version. Findings with no fix are reported and do not fail.
• npm provenance already covers the SDK; it is documented, not changed.

Consequences

• Users verify every artifact with one tool and no key of ours; the signer identity is the workflow file, so a package published by hand has no valid attestation.
• A base-image or dependency CVE with a fix blocks the next pull request that touches the image inputs until the digest or version is bumped.
• An image nobody rebuilds is not rescanned; the weekly OSV run covers the manifests only.
• The release depends on Sigstore's public-good instance and GitHub's attestation API being up.

Alternatives considered

• cosign sign plus slsa-github-generator: two tools and two verification stories for what one action does; attestations are readable by cosign verify-attestation anyway.
• Buildkit provenance: mode=max and sbom: true: unsigned, SPDX rather than CycloneDX, and the platform-list clutter ADR-0042 avoided.
• Trivy: its GitHub Action's tags were hijacked in 2026; Grype pairs with Syft, which already writes the SBOMs.