Restrict NGINX Ingress annotation values

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: restrict-annotations
  annotations:
    policies.kyverno.io/title: Restrict NGINX Ingress annotation values
    policies.kyverno.io/category: Security, NGINX Ingress
    policies.kyverno.io/severity: high
    policies.kyverno.io/subject: Ingress
    policies.kyverno.io/minversion: 1.6.0
    kyverno.io/kyverno-version: 1.6.0
    kyverno.io/kubernetes-version: "1.23"
    policies.kyverno.io/description: "This policy mitigates CVE-2021-25746 by restricting `metadata.annotations` to safe values. See: https://github.com/kubernetes/ingress-nginx/blame/main/internal/ingress/inspector/rules.go. This issue has been fixed in NGINX Ingress v1.2.0. For NGINX Ingress version 1.0.5+ the  \"annotation-value-word-blocklist\" configuration setting is also recommended.  Please refer to the CVE for details. "
spec:
  validationFailureAction: Enforce
  rules:
    - name: check-ingress
      match:
        any:
          - resources:
              kinds:
                - networking.k8s.io/v1/Ingress
      validate:
        message: spec.rules[].http.paths[].path value is not allowed
        deny:
          conditions:
            any:
              - key: "{{request.object.metadata.annotations.values(@)[].regex_match('\\s*alias\\s*.*;', @)}}"
                operator: AnyIn
                value:
                  - true
              - key: "{{request.object.metadata.annotations.values(@)[].regex_match('\\s*root\\s*.*;', @)}}"
                operator: AnyIn
                value:
                  - true
              - key: "{{request.object.metadata.annotations.values(@)[].regex_match('/etc/(passwd|shadow|group|nginx|ingress-controller)', @)}}"
                operator: AnyIn
                value:
                  - true
              - key: "{{request.object.metadata.annotations.values(@)[].regex_match('/var/run/secrets', @)}}"
                operator: AnyIn
                value:
                  - true
              - key: "{{request.object.metadata.annotations.values(@)[].regex_match('.*_by_lua.*', @)}}"
                operator: AnyIn
                value:
                  - true