Disallow Capabilities

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-capabilities
  annotations:
    policies.kyverno.io/title: Disallow Capabilities
    policies.kyverno.io/category: Pod Security Standards (Baseline)
    policies.kyverno.io/severity: medium
    kyverno.io/kyverno-version: 1.6.0
    policies.kyverno.io/minversion: 1.6.0
    kyverno.io/kubernetes-version: 1.22-1.23
    policies.kyverno.io/subject: Pod
    policies.kyverno.io/description: Adding capabilities beyond those listed in the policy must be disallowed.
spec:
  validationFailureAction: Audit
  background: true
  rules:
    - name: adding-capabilities
      match:
        any:
          - resources:
              kinds:
                - Pod
      preconditions:
        all:
          - key: "{{ request.operation || 'BACKGROUND' }}"
            operator: NotEquals
            value: DELETE
      validate:
        message: Any capabilities added beyond the allowed list (AUDIT_WRITE, CHOWN, DAC_OVERRIDE, FOWNER, FSETID, KILL, MKNOD, NET_BIND_SERVICE, SETFCAP, SETGID, SETPCAP, SETUID, SYS_CHROOT) are disallowed.
        deny:
          conditions:
            all:
              - key: "{{ request.object.spec.[ephemeralContainers, initContainers, containers][].securityContext.capabilities.add[] }}"
                operator: AnyNotIn
                value:
                  - AUDIT_WRITE
                  - CHOWN
                  - DAC_OVERRIDE
                  - FOWNER
                  - FSETID
                  - KILL
                  - MKNOD
                  - NET_BIND_SERVICE
                  - SETFCAP
                  - SETGID
                  - SETPCAP
                  - SETUID
                  - SYS_CHROOT