Skip to content
CommonLayer

Verify an image or chart

Do not take our word for it. Every published digest can be checked with standard tools against the identity its project registered.

Look up a digest

Each digest has a page with its policy results, signatures, provenance, SBOMs and the exact commands for that digest.

The steps

  1. Pin the digest. Tags are mutable pointers. Resolve the tag once, then deploy image@sha256:….
    docker buildx imagetools inspect <registry>/<image>:<tag>
  2. Verify the signature against the project's registered identity (keyless: the GitHub Actions workflow of its verified repository). The digest page gives the exact command with the right identity and issuer.
  3. Verify the attestations: the SBOM (SPDX or CycloneDX) and the SLSA provenance, signed by the same identity, whose subject is this digest.
  4. Check the vulnerability status of the digest, and remember that a fix ships as a new digest: older digests stay affected.

A valid signature proves which workflow, repository and commit produced the digest. It says nothing by itself about the security of the content, and CommonLayer does not claim a SLSA level for its builds.

Checks before anything is published

Promotion to the registry requires every check of the verification policy to pass (or to be waived by a recorded exception).
  • source.matches_manifestSource registry and repository equal the project manifest
  • digest.verifiedFetched content hashes to the submitted digest
  • version.declaredVersion belongs to a supported line in the manifest; the revision is new
  • platforms.completeEvery platform the manifest requires is present
  • image.nonrootThe image runs as a non-zero UID, unless the manifest documents a deviation
  • image.labelsRequired OCI and org.commonlayer.* labels are present and consistent
  • signature.validAt least one cosign signature verifies
  • signature.identitySigner identity and issuer match the project's registered identity
  • sbom.presentA signed SBOM attestation exists for every platform
  • sbom.parsableThe SBOM parses and lists components
  • provenance.presentA signed SLSA provenance attestation exists
  • provenance.subjectThe provenance subject digest equals the artifact digest
  • provenance.sourceThe provenance source is a verified repository of the project and the commit matches
  • scan.freshA successful scan by at least one scanner completed for this digest
  • scan.gateNo fixable finding at or above the gate severity without an exception
  • chart.images_pinnedChart default images are digests of promoted CommonLayer images
  • chart.schemaThe chart ships values.schema.json