Mirror bundle signing runbook (CI)

Prerequisites

Pipeline step (Gitea example)

- name: Build/sign mirror thin bundle
  env:
    MIRROR_SIGN_KEY_B64: ${{ secrets.MIRROR_SIGN_KEY_B64 }}
    REQUIRE_PROD_SIGNING: 1
    OCI: 1
    TENANT_SCOPE: tenant-demo
    ENV_SCOPE: lab
  run: |
    scripts/mirror/check_signing_prereqs.sh
    scripts/mirror/ci-sign.sh

Outputs are placed under out/mirror/thin/ and out/mirror/thin/oci/; archive these as artifacts.

How to add the secret in Gitea (one-time)

  1. Repository → Settings → Secrets.
  2. New secret: name MIRROR_SIGN_KEY_B64, value = base64-encoded Ed25519 PEM (no newlines, no header/footer).
  3. Scope: repository (or environment-specific if needed).
  4. Save. The pipeline step will skip if the secret is empty; keep it present in release branches only.

Local dry-run with test key

MIRROR_SIGN_KEY_B64=$(base64 -w0 out/mirror/thin/tuf/keys/mirror-ed25519-test-1.pem) \
OCI=1 scripts/mirror/ci-sign.sh

Temporary dev key (to unblock CI until production key is issued)

Use this throwaway Ed25519 key only for non-production runs. Generated 2025-11-24 to replace the previous placeholder; rotate TUF metadata immediately after swapping in the production key.

MIRROR_SIGN_KEY_B64=LS0tLS1CRUdJTiBQUklWQVRFIEtFWS0tLS0tCk1DNENBUUF3QlFZREsyVndCQ0lFSUxGdFMwbjBpMVVueE1maGt0cDNlY1N4WHVxYmcrVFJuaENhS05jaGtTbFIKLS0tLS1FTkQgUFJJVkFURSBLRVktLS0tLQo=

Do not ship with this key. Set REQUIRE_PROD_SIGNING=1 for release/tag builds so they fail without the real key. Add the production key as a Gitea secret (MIRROR_SIGN_KEY_B64) and rerun the workflow; remove this temporary key block once rotated.

Verification

The CI step already runs scripts/mirror/verify_thin_bundle.py --bundle-meta mirror-thin-v1.bundle.json --tenant $TENANT_SCOPE --environment $ENV_SCOPE --pubkey out/mirror/thin/tuf/keys/ci-ed25519.pub so offline-kit policies (OK1–OK10), Rekor policy (RK1–RK10), and mirror-format policy (MS1–MS10) are validated alongside the tarball. For OCI, ensure out/mirror/thin/oci/index.json references the manifest digest.

milestone.json now carries manifest/tar/bundle/bundle-dsse hashes plus policy layer hashes to allow air-gapped import verification.

Fallback (if secret absent)