Disallow Privilege Escalation

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: disallow-privilege-escalation
  annotations:
    policies.kyverno.io/title: Disallow Privilege Escalation
    policies.kyverno.io/category: Pod Security Standards (Restricted)
    policies.kyverno.io/severity: medium
    policies.kyverno.io/subject: Pod
    kyverno.io/kyverno-version: 1.6.0
    kyverno.io/kubernetes-version: 1.22-1.23
    policies.kyverno.io/description: Privilege escalation, such as via set-user-ID or set-group-ID file mode, should not be allowed. This policy ensures the `allowPrivilegeEscalation` field is set to `false`.
spec:
  validationFailureAction: Audit
  background: true
  rules:
    - name: privilege-escalation
      match:
        any:
          - resources:
              kinds:
                - Pod
      validate:
        message: Privilege escalation is disallowed. The fields spec.containers[*].securityContext.allowPrivilegeEscalation, spec.initContainers[*].securityContext.allowPrivilegeEscalation, and spec.ephemeralContainers[*].securityContext.allowPrivilegeEscalation must be set to `false`.
        pattern:
          spec:
            "=(ephemeralContainers)":
              - securityContext:
                  allowPrivilegeEscalation: "false"
            "=(initContainers)":
              - securityContext:
                  allowPrivilegeEscalation: "false"
            containers:
              - securityContext:
                  allowPrivilegeEscalation: "false"