Chapter 10. Configuring seccomp profiles An OpenShift Container Platform container or a pod runs a single application that performs one or more well-defined tasks. The application usually requires only a small subset of the underlying operating system kernel APIs. Seccomp, secure computing mode, is a Linux kernel feature that can be used to limit the process running in a container to only call a subset of the available system calls. These system calls can be configured by creating a profile that is applied to a container or pod. Seccomp profiles are stored as JSON files on the disk. Important OpenShift workloads run unconfined by default, without any seccomp profile applied. Important Seccomp profiles cannot be applied to privileged containers. 10.1. Enabling the default seccomp profile for all pods OpenShift Container Platform ships with a default seccomp profile that is referenced as runtime/default . You can enable the default seccomp profile for a pod or container workload by creating a custom Security Context Constraint (SCC). Note There is a requirement to create a custom SCC. Do not edit the default SCCs. Editing the default SCCs can lead to issues when some of the platform pods deploy or OpenShift Container Platform is upgraded. For more information, see the section entitled "Default security context constraints". Follow these steps to enable the default seccomp profile for all pods: Export the available restricted SCC to a yaml file: USD oc get scc restricted -o yaml > restricted-seccomp.yaml Edit the created restricted SCC yaml file: USD vi restricted-seccomp.yaml Update as shown in this example: kind: SecurityContextConstraints metadata: name: restricted 1 <..snip..> seccompProfiles: 2 - runtime/default 3 1 Change to restricted-seccomp 2 Add seccompProfiles: 3 Add - runtime/default Create the custom SCC: USD oc create -f restricted-seccomp.yaml Expected output securitycontextconstraints.security.openshift.io/restricted-seccomp created Add the custom SCC to the ServiceAccount: USD oc adm policy add-scc-to-user restricted-seccomp -z default Note The default service account is the ServiceAccount that is applied unless the user configures a different one. OpenShift Container Platform configures the seccomp profile of the pod based on the information in the SCC. Expected output clusterrole.rbac.authorization.k8s.io/system:openshift:scc:restricted-seccomp added: "default" In OpenShift Container Platform 4.9 the ability to add the pod annotations seccomp.security.alpha.kubernetes.io/pod: runtime/default and container.seccomp.security.alpha.kubernetes.io/<container_name>: runtime/default is deprecated. 10.2. Configuring a custom seccomp profile You can configure a custom seccomp profile, which allows you to update the filters based on the application requirements. This allows cluster administrators to have greater control over the security of workloads running in OpenShift Container Platform. 10.2.1. Setting up the custom seccomp profile Prerequisite You have cluster administrator permissions. You have created a custom security context constraints (SCC). For more information, see "Additional resources". You have created a custom seccomp profile. Procedure Upload your custom seccomp profile to /var/lib/kubelet/seccomp/<custom-name>.json by using the Machine Config. See "Additional resources" for detailed steps. Update the custom SCC by providing reference to the created custom seccomp profile: seccompProfiles: - localhost/<custom-name>.json 1 1 Provide the name of your custom seccomp profile. 10.2.2. Applying the custom seccomp profile to the workload Prerequisite The cluster administrator has set up the custom seccomp profile. For more details, see "Setting up the custom seccomp profile". Procedure Apply the seccomp profile to the workload by setting the securityContext.seccompProfile.type field as following: Example spec: securityContext: seccompProfile: type: Localhost localhostProfile: <custom-name>.json 1 1 Provide the name of your custom seccomp profile. Alternatively, you can use the pod annotations seccomp.security.alpha.kubernetes.io/pod: localhost/<custom-name>.json . However, this method is deprecated in OpenShift Container Platform 4.9. During deployment, the admission controller validates the following: The annotations against the current SCCs allowed by the user role. The SCC, which includes the seccomp profile, is allowed for the pod. If the SCC is allowed for the pod, the kubelet runs the pod with the specified seccomp profile. Important Ensure that the seccomp profile is deployed to all worker nodes. Note The custom SCC must have the appropriate priority to be automatically assigned to the pod or meet other conditions required by the pod, such as allowing CAP_NET_ADMIN. 10.3. Additional resources Managing security context constraints Post-installation machine configuration tasks

Commands:
oc get scc restricted -o yaml > restricted-seccomp.yaml
vi restricted-seccomp.yaml
kind: SecurityContextConstraints metadata: name: restricted 1 <..snip..> seccompProfiles: 2 - runtime/default 3
oc create -f restricted-seccomp.yaml
securitycontextconstraints.security.openshift.io/restricted-seccomp created
oc adm policy add-scc-to-user restricted-seccomp -z default
clusterrole.rbac.authorization.k8s.io/system:openshift:scc:restricted-seccomp added: "default"
seccompProfiles: - localhost/<custom-name>.json 1
spec: securityContext: seccompProfile: type: Localhost localhostProfile: <custom-name>.json 1