Restrict Volume Types in CEL

 1apiVersion: kyverno.io/v1
 2kind: ClusterPolicy
 3metadata:
 4  name: restrict-volume-types
 5  annotations:
 6    policies.kyverno.io/title: Restrict Volume Types in CEL
 7    policies.kyverno.io/category: Pod Security Standards (Restricted) in CEL
 8    policies.kyverno.io/severity: medium
 9    policies.kyverno.io/subject: Pod,Volume
10    policies.kyverno.io/minversion: 1.11.0
11    kyverno.io/kubernetes-version: "1.26-1.27"
12    kyverno.io/kyverno-version: 1.11.0
13    policies.kyverno.io/description: >-
14      In addition to restricting HostPath volumes, the restricted pod security profile
15      limits usage of non-core volume types to those defined through PersistentVolumes.
16      This policy blocks any other type of volume other than those in the allow list.      
17spec:
18  validationFailureAction: Audit
19  background: true
20  rules:
21    - name: restricted-volumes
22      match:
23        any:
24        - resources:
25            kinds:
26              - Pod
27      validate:
28        cel: 
29          expressions:
30            - expression: >- 
31                !has(object.spec.volumes) ||
32                object.spec.volumes.all(vol, has(vol.configMap) ||
33                has(vol.csi) ||
34                has(vol.downwardAPI) ||
35                has(vol.emptyDir) ||
36                has(vol.ephemeral) ||
37                has(vol.persistentVolumeClaim) ||
38                has(vol.projected) ||
39                has(vol.secret))
40              message: >-
41                Only the following types of volumes may be used: configMap, csi, downwardAPI,
42                emptyDir, ephemeral, persistentVolumeClaim, projected, and secret.