restrict-clusteradmin-rolebindings.yaml

# Copyright 2024 Google LLC
#
# This is “Software” that is licensed under the “General Software” section of
# the Service Specific Terms (https://cloud.google.com/terms/service-terms) for
# usage in accordance with the following “Scope of Use”: This file may only be
# used on an Anthos cluster, including any associated ci/cd use. “Anthos
# cluster” is defined as “A Cluster (of any kind) registered to a fleet project
# where the Anthos API is enabled”.
apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sRestrictRoleBindings
metadata:
  name: nist-sp-800-53-r5-restrict-clusteradmin-rolebindings
  labels:
    policycontroller.gke.io/bundleName: nist-sp-800-53-r5
  annotations:
    policycontroller.gke.io/bundleVersion: "202403.0"
    policycontroller.gke.io/constraintData: |-
      "{
        bundleName: 'nist-sp-800-53-r5',
        bundleDisplayName: 'NIST SP 800-53 Rev. 5',
        bundleLink: 'https://cloud.google.com/anthos-config-management/docs/how-to/using-nist-sp-800-53-r5',
        bundleVersion: '202403.0',
        bundleDescription: 'Use the NIST SP 800-53 Rev. 5 policy bundle with Policy Controller to evaluate the compliance of your cluster resources against some aspects of the NIST SP 800-53 Rev. 5 controls.',
        controlNumbers: '[AC-6,CM-4,CM-5,CM-7]',
        severity: 'UNSPECIFIED',
        description: 'Restricts the use of the `cluster-admin` role.',
        remediation: 'Cannot use the cluster-admin `ClusterRole` for Role-based access control (RBAC). Use a different role. See "Using RBAC Authorization" for more information: https://kubernetes.io/docs/reference/access-authn-authz/rbac/#user-facing-roles',
        minimumTemplateLibraryVersion: '1.10.1',
        constraintHash: 'ac5260c6134d9b1be59afb4da0b5576ae2fda24fb4178a60f295660b5f702f26'
      }"
spec:
  enforcementAction: dryrun
  match:
    kinds:
      - apiGroups:
          - rbac.authorization.k8s.io
        kinds:
          - ClusterRoleBinding
          - RoleBinding
  parameters:
    restrictedRole:
      apiGroup: rbac.authorization.k8s.io
      kind: ClusterRole
      name: cluster-admin
    allowedSubjects:
      - apiGroup: rbac.authorization.k8s.io
        kind: Group
        name: system:masters
      # for GKE Hub feature authorizer
      - apiGroup: rbac.authorization.k8s.io
        kind: User
        name: ^service-[0-9]+@gcp-sa-gkehub.iam.gserviceaccount.com$
        regexMatch: true
      # for ACM to install in-cluster resources
      - apiGroup: rbac.authorization.k8s.io
        kind: User
        name: ^service-[0-9]+@gcp-sa-anthosconfigmanagement.iam.gserviceaccount.com$
        regexMatch: true
      # for Config Sync reconciler service account
      - kind: ServiceAccount
        name: reconciler-manager
      # for Config Sync admission webhook
      - kind: ServiceAccount
        name: admission-webhook
      # For kube-storage-version-migrator, part of the GKE control plane
      - apiGroup: rbac.authorization.k8s.io
        kind: User
        name: system:storageversionmigrator
      # Kubernetes service account for Config Sync reconciler
      # https://cloud.google.com/anthos-config-management/docs/how-to/installing-config-sync#git-creds-secret
      - kind: ServiceAccount
        name: ^root-reconciler[a-z0-9-]*$
        regexMatch: true
      # for GKE Autopilot
      - kind: ServiceAccount
        name: system:gke-vpa-target-reader
      - kind: ServiceAccount
        name: serviceaccount-cluster-admin