sbom-operator

Catalogue all images of a Kubernetes cluster to multiple targets with Syft.

Overview

This operator maintains a central place to track all packages and software used in all those images in a Kubernetes cluster. For this a Software Bill of Materials (SBOM) is generated from each image with Syft. They are all stored in one or more targets. Currently Git, Dependency Track, OCI-Registry and ConfigMaps are supported. With this it is possible to do further analysis, vulnerability scans and much more in a single place. To prevent scans of images that have already been analyzed pods are annotated with the imageID of the already processed image.

Kubernetes Compatibility

The image contains versions of k8s.io/client-go. Kubernetes aims to provide forwards & backwards compatibility of one minor version between client and server:

However, the operator will work with more versions of Kubernetes in general.

Container Registry Support

The operator relies on the go-containeregistry library to download images. It should work with most registries. These are officially tested (with authentication):

• ACR (Azure Container Registry) (currently not unit-tested)
• ECR (Amazon Elastic Container Registry)
• GAR (Google Artifact Registry)
• GCR (Google Container Registry)
• GHCR (GitHub Container Registry)
• DockerHub

Installation

Manifests

kubectl apply -f deploy/standard/

Helm-Chart

Create a YAML file first with the required configurations or use helm-flags instead.

helm repo add ckotzbauer https://ckotzbauer.github.io/helm-charts
helm install ckotzbauer/sbom-operator -f your-values.yaml

Configuration

All parameters are cli-flags. The flags can be configured as args or as environment-variables prefixed with SBOM_ to inject sensitive configs as secret values.

Common parameters

Example Helm-Config

args:
  targets: git
  git-author-email: XXX
  git-author-name: XXX
  git-repository: https://github.com/XXX/XXX
  git-path: dev-cluster/sboms
  verbosity: debug
  cron: "0 30 * * * *"

envVars:
  - name: SBOM_GIT_ACCESS_TOKEN
    valueFrom:
      secretKeyRef:
        name: "sbom-operator"
        key: "accessToken"

Analysis-Trigger

Cron

With the cron flag set, the operator runs with a specified interval and checks for changed images in your cluster. All options from github.com/robfig/cron are allowed as cron-syntax.

Real-Time

When you omit the cron flag, the operator uses a Cache-Informer to process changed pods immediately. In this mode there's also a one-time analysis at startup to sync the targets with the actual cluster-state. If you configured a job-image there's no initial startup sync.

Targets

It is possible to store the generated SBOMs to different targets (even multple at once). All targets are using Syft as analyzer. If you want to use another tool to analyze your images, then have a look at the Job image section. Images which are not present in the cluster anymore are removed from the configured targets (except for the OCI-Target).

Dependency Track

Dependency Track Parameter

Each image in the cluster is created as project with the full-image name (registry and image-path without tag) and the image-tag as project-version. When there's no image-tag, but a digest, the digest is used as project-version. The autoCreate option of DT is used. You have to set the --format flag to cyclonedx with this target.

Git

Git Parameter

The operator will save all files with a specific folder structure as described below. When a git-path is configured, all folders above this path are not touched from the application. Assuming that git-path is set to dev-cluster/sboms. When no git-path is given, the structure below is directly in the repository-root. The structure is basically <git-path>/<registry-server>/<image-path>/<image-digest>/sbom.json (see example below). The file-extension may differ when another output-format is configured. You can use a token-based authentication (e.g. a PAT for GitHub) with --git-access-token, BasicAuth with username and password (--git-username, --git-password) or Github App Authentication (--github-app-id, --github-app-installation-id, env: SBOM_GITHUB_APP_PRIVATE_KEY) The private-key has to be Base64 encoded. To clone repositories with a git-binary instead of the pure golang implementation, add the --git-fallback-clone flag. This is needed for Git-Providers which need multi_ack e.g. Azure DevOps or AWS CodeCommit. See this issue for more details.

Note: It is required, that the specified branch of the repo is fully initialized. There's no logic which creates a non-existent branch. Just commit a README.md or something similar, to make things work.

dev-cluster
│
└───sboms
    │
    └───docker.io
    |   │
    |   └───library
    |       │
    |       └───busybox
    |           │
    |           └───sha256_ae39a6f5...
    |               │   sbom.json
    |
    └───ghcr.io
        │
        └───kyverno
            │
            └───kyverno
            |   │
            |   └───sha256_9e3f14e5...
            |       │   sbom.json
            |
            └───kyvernopre
                │
                └───sha256_e48f87fd...
                    │   sbom.json
            |
            └───policy-reporter
                │
                └───sha256_b70caa7a...
                    │   sbom.json

OCI-Registry

OCI-Registry Parameter

In this mode the operator will generate a SBOM and store it into an OCI-Registry. The SBOM then can be processed by cosign, Kyverno or any other tool. E.g.:

COSIGN_REPOSITORY=<yourregistry> cosign download sbom <your full image digest>

The operator needs the Registry-URL, a user and a token as password to authenticate to the registry. Write-permissions are needed.

ConfigMap

This target stores the SBOM as Kubernetes-ConfigMap. They are placed in the same namespace as the corresponding pod and the name consists of the pod- and container-name. The configmap is labeled with ckotzbauer.sbom-operator.io=true and annotated with ckotzbauer.sbom-operator.io/image-id=<full-image-repo-with-digest>. The content is stored as broli-compressed binary-data with the configmap-key sbom.

Job-Images

Job-Image Parameter

If you don't want to use Syft to analyze your images, you can give the Job-Image feature a try. The operator creates a Kubernetes-Job which does the analysis with any possible tool inside. There's no target-handling done by the operator, the tool from the job has to process the SBOMs on its own. Currently there are two possible integrations:

This feature is built as generic approach. Any image which follows these specs can be used as job-image.

e.g. Manifest (deploy/job-image):

--job-image=ghcr.io/ckotzbauer/sbom-operator/cas:<TAG>

e.g. Helm:

jobImageMode: true

envVars:
  - name: SBOM_JOB_CAS_API_KEY
    value: "<KEY>"

All operator-environment variables prefixed with SBOM_JOB_ are passed to the Kubernetes job.

Security

The docker-image is based on a distroless git-image to reduce the attack-surface and keep the image small. Furthermore the image and release-artifacts are signed with cosign and attested with provenance-files. The release-process satisfies SLSA Level 2. All of those "metadata files" are also stored in a dedicated repository ghcr.io/ckotzbauer/sbom-operator-metadata. When discovering security issues please refer to the Security process.

Signature verification

COSIGN_EXPERIMENTAL=1 COSIGN_REPOSITORY=ghcr.io/ckotzbauer/sbom-operator-metadata cosign verify ghcr.io/ckotzbauer/sbom-operator:<tag-to-verify> --certificate-github-workflow-name create-release --certificate-github-workflow-repository ckotzbauer/sbom-operator

Attestation verification

COSIGN_EXPERIMENTAL=1 COSIGN_REPOSITORY=ghcr.io/ckotzbauer/sbom-operator-metadata cosign verify-attestation ghcr.io/ckotzbauer/sbom-operator:<tag-to-verify> --certificate-github-workflow-name create-release --certificate-github-workflow-repository ckotzbauer/sbom-operator

Download attestation

COSIGN_REPOSITORY=ghcr.io/ckotzbauer/sbom-operator-metadata cosign download attestation ghcr.io/ckotzbauer/sbom-operator:<tag-to-verify> | jq -r '.payload' | base64 -d

Download SBOM

COSIGN_REPOSITORY=ghcr.io/ckotzbauer/sbom-operator-metadata cosign download sbom ghcr.io/ckotzbauer/sbom-operator:<tag-to-verify> | jq -r '.payload' | base64 -d

License

Changelog

Contributing

Please refer to the Contribution guildelines.

Code of conduct

Please refer to the Conduct guildelines.