image-tools/README.md

image-tools

Judges, signs and verifies the container images of netOrk. Every image repository of NetOrk uses these tools at a pinned commit, so the same rules apply to every link of the chain:

netork/base-os ──► netork/base-python ──► netork/engine, netork/satellite
               └─► netork/ui
               └─► postgres, valkey, signal-api, apt-cacher-ng, unbound

Each link checks the signature of the image it builds on, is judged against CIS, and is signed with its CIS result and SBOM attached (NetOrk/netork#1390).

What it does

CIS gate (image_tools/cis.py)	CIS Docker Benchmark 1.6.0 §4 and the CIS Debian Linux 12 controls that make sense in a container. Trivy measures what it automates; image_tools/cis_os.sh measures from inside the image. The image's repository decides the rest in its cis.toml and names the packages it may hold in packages.allow.
SBOM (image_tools/sbom.py)	The image's CycloneDX SBOM, as Trivy reads it.
Signature (bin/sign.sh)	A cosign signature on the reference and on every platform image behind it, with the CIS result and the SBOM as in-toto attestations. Nothing goes to a public transparency log.
Verification (bin/verify-base.sh, bin/verify-signature.sh)	Every FROM image of a Dockerfile is pinned by digest and signed with the key in cosign.pub.
Verdict (image_tools/verify.py)	Whether a rebuild improves on the pinned image, by netOrk's matcher (kb-server), for a base's nightly.
Bump (image_tools/bump.py)	One pull request in every repository of a dependents.toml that moves only the pin, and that repository's workflow started.

Using it in a workflow

- name: Verify the base images
  uses: https://git.netork.io/NetOrk/image-tools/actions/verify-base@<commit>
  with:
    dockerfiles: docker/engine/Dockerfile

# build the image, then:
- name: Judge it
  uses: https://git.netork.io/NetOrk/image-tools/actions/judge@<commit>
  with:
    image: registry.netork.io/netork/engine:main-abc1234
    arch: amd64

# a base's nightly, to decide whether its pin moves:
- name: Judge it against the pin
  id: verdict
  uses: https://git.netork.io/NetOrk/image-tools/actions/verdict@<commit>
  env:
    NETORK_LICENSE_KEY: ${{ secrets.NETORK_LICENSE_KEY }}
  with:
    current: registry.netork.io/netork/base-os:pinned
    candidate: registry.netork.io/netork/base-os:13-20261022.3-amd64

# push it, then:
- name: Sign it
  uses: https://git.netork.io/NetOrk/image-tools/actions/sign@<commit>
  env:
    COSIGN_PRIVATE_KEY_B64: ${{ secrets.COSIGN_PRIVATE_KEY_B64 }}
    COSIGN_PASSWORD: ${{ secrets.COSIGN_PASSWORD }}
  with:
    ref: registry.netork.io/netork/engine@sha256:…

The judge action reads cis.toml and packages.allow from the working directory by default. The runner needs Docker, Python 3.11 or newer, and curl; cosign is installed by the actions, pinned and checked against its release checksum (bin/install-cosign.sh).

Verifying an image yourself

# The signature, on the tag or digest you pull (an index is signed with every image in it):
cosign verify --key cosign.pub --insecure-ignore-tlog registry.netork.io/netork/engine:latest-dev

# The CIS result and the SBOM belong to each platform image, not to the index around it:
docker buildx imagetools inspect registry.netork.io/netork/engine:latest-dev   # the linux/amd64 digest
cosign verify-attestation --key cosign.pub --insecure-ignore-tlog \
  --type https://netork.io/attestations/cis/v1 registry.netork.io/netork/engine@sha256:<platform digest>
cosign verify-attestation --key cosign.pub --insecure-ignore-tlog \
  --type cyclonedx registry.netork.io/netork/engine@sha256:<platform digest>

Even a single-platform image is pushed as an index: BuildKit adds its provenance manifest.

cosign.pub is the public half of the COSIGN_PRIVATE_KEY_B64 organization secret. The private key comes base64 in one line: the runner masks a secret only where it appears whole.

Development

pip install pytest ruff pyyaml shellcheck-py
pytest -q
ruff format --check . && ruff check .
shellcheck bin/*.sh image_tools/cis_os.sh

License

MIT, see LICENSE.