kyverno/samples/DisallowNewCapabilities.md

Disallow new capabilities

Linux allows defining fine-grained permissions using capabilities. With Kubernetes, it is possible to add capabilities that escalate the level of kernel access and allow other potentially dangerous behaviors. This policy enforces that pods cannot add new capabilities. Other policies can be used to set default capabilities.

Policy YAML

disallow_new_capabilities.yaml

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-new-capabilities
spec:
  rules:
  - name: validate-add-capabilities
    match:
      resources:
        kinds:
        - Pod
    validate:
      message: "New capabilities cannot be added"
      anyPattern:
      - spec:
        =(securityContext):
          =(capabilities):
            X(add): null
      - spec:
          containers:
          - name: "*"
            =(securityContext):
              =(capabilities):
                X(add): null