Local Path Provisioner: HelperPod Template Injection

Local Path Provisioner provides a way for the Kubernetes users to utilize the local storage in each node. Prior to 0.0.36, a malicious user with permission to edit the local-path-config ConfigMap in the local-path-storage namespace can manipulate the helperPod.yaml template used by rancher/local-path-provisioner. The helperPod.yaml template is loaded by the provisioner and used to create HelperPods during PVC provisioning and cleanup operations. However, the template is not sufficiently validated before use. Security-sensitive fields such as securityContext.privileged, hostPath volumes, and Linux capabilities can be injected into the template. When a PVC operation triggers HelperPod creation, the provisioner creates the HelperPod using the attacker-controlled template. This can result in a privileged pod running on the target node with the host root filesystem mounted. This may allow the attacker to access sensitive host files, read ServiceAccount tokens from other pods on the same node, access other tenants' local-path volume data, or modify files on the host node. This vulnerability is fixed in 0.0.36.