# based on https://kyverno.io/policies/pod-security/baseline/disallow-host-ports/disallow-host-ports/
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-host-ports
  annotations:
    policies.kyverno.io/category: Pod Security Standards (Baseline)
    policies.kyverno.io/severity: medium
    policies.kyverno.io/subject: Pod
    policies.kyverno.io/description: >-
      Access to host ports allows potential snooping of network traffic and should not be
      allowed, or at minimum restricted to a known list.      
spec:
  validationFailureAction: audit
  background: true
  rules:
    - name: host-ports
      match:
        resources:
          kinds:
            - Pod
      exclude:
        resources:
          namespaces:
            - calico-system
            - monitoring
      validate:
        message: >-
          Use of host ports is disallowed. The fields spec.containers[*].ports[*].hostPort
          and spec.initContainers[*].ports[*].hostPort must be empty.          
        pattern:
          spec:
            =(initContainers):
              - =(ports):
                  - X(hostPort): 0
            containers:
              - =(ports):
                  - X(hostPort): 0