Policy Input

The policy input refers the variable input in rego. This page describes the structure of the input available for policy evaluation when using the Enterprise Contract CLI. The input is different for each subcommand as each subcommand has a different specialty.

Validate Image

The input format for the validate image command describes all the information related to the image being available. Not all information is available for all images. This is noted below in the description of each attribute.

It is important to note that this command may proccess multiple images at the same time. In such cases, a different input is generated for each image. In other words, policy rules only eve have access to the information about a single image.

    "attestations": [
            "statement": {
                "_type": "https://in-toto.io/Statement/v0.1",
                "predicate": {...},
                "predicateType": "https://slsa.dev/provenance/v0.2",
                "subject": [...],
            "signatures": [...#SignatureDescriptor]
    "image": #ImageDescriptor

#ImageDescriptor: {
    "config": {...},
    "parent": #ImageDescriptor,
    "ref": "<STRING>",
    "signatures": [...#SignatureDescriptor],
    "files": {...},
    "source": #SourceDescriptor

#SignatureDescriptor: {
    "keyid": "<STRING>",
    "sig": "<STRING>",
    "certificate": "<STRING>",
    "chain": [..."<STRING>"],
    "metadata": {...}

#SourceDescriptor: {
    "git": {
        "revision": "<STRING>",
        "url": "<STRING>"

.attestations is an array of objects. Each object contains the .statement and the .signatures attributes. .statement represents a SLSA Provenance v0.2 statement. See schema for details. .signatures contains information about the signatures associated with the statement.

.image is an object representing the image being validated.

.image.config holds the OCI config for the image. It may contain various attributes, such as .Labels, Env, and Cmd. The set of attributes available depends on what is set on the OCI image config. See the config property definition for more details.

.image.parent is an ImageDescriptor for the parent image of the image being validated. This is only present if the image being validated contains the expected annotations: org.opencontainers.image.base.name and org.opencontainers.image.base.digest.

.image.ref is a string containing a reference to the image. A digest is always included, but a tag is not.

.image.signatures is an array of signature descriptors associated with the image.

The contents of the SignatureDescriptor objects varies depending on the form of signature validation used. .keyid holds the ID of the key used for signing. sig is the signature of the resource. .certificate and chain holds PEM encoded certificates. These two are only available when short-lived keys are used, aka keyless workflow.

Use the policy-input output format to save the input object to a file, e.g. ec validate image …​ --output=input.jsonl.

.image.files is an object where each attribute represents the full path of a file within the image, and the value is the content of such file converted to JSON format. Paths do not start with a leading /. If the contents of a file cannot be converted to JSON format, that file is skipped. Currently, there are two sets of files that may be included. First, if the image contains the label operators.operatorframework.io.bundle.manifests.v1, all the files within the path specified by the label are included. If the image contains the label vendor and its value is Red Hat, Inc., then all files under root/buildinfo/content_manifests are included.

.image.source contains information about the source code used to generate the image. Currently, the only version control system supported is git. This information originates from the ApplicationSnapshot provided to the ec validate image command. It is empty if the source information is not given to the command.

The SourceDescriptor contains the the single git attribute which hold an object with information about a git repository. .revision is a string holding a git reference. This could be a commit ID, branch, etc. url is the the URL of the git repository.