← Policy catalog
</> ValidatingAdmissionPolicy · Apache-2.0

Sets a Custom SELinux User

pod-selinux-user

severityModerate resourcePods productKubernetes bundles2

A custom SELinux user label at pod level replaces the confined context the runtime assigns to every container, granting a policy domain with transitions and file access the sandbox was never meant to allow.

Rejects unless

!has(object.spec.securityContext) || !has(object.spec.securityContext.seLinuxOptions) || !has(object.spec.securityContext.seLinuxOptions.user) || object.spec.securityContext.seLinuxOptions.user == ""

spec.securityContext.seLinuxOptions.user must be undefined or an empty string ("").

Remediation

Remove the pod-level seLinuxOptions.user setting or leave it as an empty string so the runtime assigns its default SELinux user. Field: spec.securityContext.seLinuxOptions.user.

Applies to

  • pods · v1 · CREATE, UPDATE

Manifest

apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicy
metadata:
  name: pod-selinux-user
  annotations:
    kubeapt.io/uuid: "2d1a986b-a524-422b-83b0-aafe9cd95f55"
    security.kubeapt.io/displayName: "Sets a Custom SELinux User"
    security.kubeapt.io/description: "A custom SELinux user label at pod level replaces the confined context the runtime assigns to every container, granting a policy domain with transitions and file access the sandbox was never meant to allow."
    security.kubeapt.io/resource: "Pods"
    security.kubeapt.io/severity: "Moderate"
    security.kubeapt.io/remediation: "Remove the pod-level seLinuxOptions.user setting or leave it as an empty string so the runtime assigns its default SELinux user. Field: spec.securityContext.seLinuxOptions.user."
    security.kubeapt.io/product: "Kubernetes"
spec:
  failurePolicy: Fail
  matchConstraints:
    resourceRules:
    - apiGroups:
      - ''
      apiVersions:
      - v1
      operations:
      - CREATE
      - UPDATE
      resources:
      - pods
  validations:
  - expression: |
      !has(object.spec.securityContext) || !has(object.spec.securityContext.seLinuxOptions) || !has(object.spec.securityContext.seLinuxOptions.user) || object.spec.securityContext.seLinuxOptions.user == ""
    message: |
      spec.securityContext.seLinuxOptions.user must be undefined or an empty string ("").

Save it as pod-selinux-user.yaml — the commands below assume that name.

Validate with kubeapt

Check a workload against this one policy, before anything is installed on a cluster.

$ kubeapt validate -p ./pod-selinux-user.yaml -r ./workload.yaml

Or without the file, from the published policy set — -r takes a directory too:

$ kubeapt policies download && kubeapt validate --policy-name pod-selinux-user -r ./manifests

Or against every namespace in the cluster your kubeconfig points at:

$ kubeapt validate --policy-name pod-selinux-user -A

Bundles

Source

View policy.yaml on GitHub →