kyverno/charts/kyverno-policies/templates/baseline/disallow-proc-mount.yaml

{{- $name := "disallow-proc-mount" }}
{{- if eq (include "kyverno-policies.podSecurityBaseline" (merge (dict "name" $name) .)) "true" }}
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: {{ $name }}
  annotations:
    policies.kyverno.io/title: Disallow procMount
    policies.kyverno.io/category: Pod Security Standards (Baseline)
    {{- if .Values.podSecuritySeverity }}
    policies.kyverno.io/severity: {{ .Values.podSecuritySeverity }}
    {{- end }}
    policies.kyverno.io/subject: Pod
    kyverno.io/kyverno-version: 1.6.0
    kyverno.io/kubernetes-version: "1.22-1.23"
    policies.kyverno.io/description: >-
      The default /proc masks are set up to reduce attack surface and should be required. This policy
      ensures nothing but the default procMount can be specified. Note that in order for users
      to deviate from the `Default` procMount requires setting a feature gate at the API
      server.
spec:
  validationFailureAction: {{ .Values.validationFailureAction }}
  {{- with concat (index .Values "validationFailureActionOverrides" "all") (default list (index .Values "validationFailureActionOverrides" $name)) }}
  validationFailureActionOverrides: {{ toYaml . | nindent 4 }}
  {{- end }}
  background: true
  rules:
    - name: check-proc-mount
      match:
        any:
        - resources:
            kinds:
              - Pod
      {{- with index .Values "policyExclude" $name }}
      exclude:
        {{- toYaml . | nindent 8 }}
      {{- end }}
      validate:
        message: >-
          Changing the proc mount from the default is not allowed. The fields
          spec.containers[*].securityContext.procMount, spec.initContainers[*].securityContext.procMount,
          and spec.ephemeralContainers[*].securityContext.procMount must be unset or
          set to `Default`.
        pattern:
          spec:
            =(ephemeralContainers):
              - =(securityContext):
                  =(procMount): "Default"
            =(initContainers):
              - =(securityContext):
                  =(procMount): "Default"
            containers:
              - =(securityContext):
                  =(procMount): "Default"
{{- end }}