Andrei Kvapil
02c6942adc
## What this PR does Closes the exposure behind GHSA-g883-q79m-8225 by constraining who can reach the kube-ovn webhook's serving port. The `/mutate-pods` handler returns namespace-derived annotations to any caller that reaches it, and until now nothing stopped an arbitrary in-cluster pod from being that caller. ### Why the client-certificate path does not close it cozystack/cozystack#2698 added `--client-ca-file`, deliberately off by default, as observation mode. Turning it on requires the API server to **present** a certificate, which it does only when its `AdmissionConfiguration` names a `kubeConfigFile` for the webhook plugins. Checked against a running Cozystack control plane rather than assumed: the `AdmissionConfiguration` there carries a `PodSecurity` plugin block and nothing else, so no client certificate is offered to admission webhooks at all. Flipping to `RequireAndVerifyClientCert` on such a cluster would reject the API server itself, and with `failurePolicy: Fail` that stops pod creation cluster-wide. This matters for how the remaining work was scoped: the plan had been to observe issuer logs for a day and then pin a CA. No amount of observation changes the outcome, because the absence is a property of the control plane's configuration, not of the traffic. Making `--client-ca-file` usable is a separate, larger change to how the platform configures the API server, and it is not a prerequisite for closing the exposure. ### What the policy does Denies pod traffic and world traffic to the serving port, and needs no carve-out for the legitimate caller: the API server runs on the host network, so it is not a Cilium endpoint and `fromEndpoints` never matches it. Unlike the ingress-nginx admission webhook this component exists only on the management cluster, so there is no konnectivity-tunnelled caller to exempt either — and consequently no forgeable pod label anywhere in the selector. It is a `CiliumNetworkPolicy` rather than a core `NetworkPolicy`, and that distinction is the reason it works at all: `packages/system/kubeovn/values.yaml` sets `ENABLE_NP: false`, so kube-ovn programs no ACLs and a core NetworkPolicy would be created and never enforced. The values comment that claimed NetworkPolicy was simply not an option is corrected — it was true only of the core kind. `webhookPolicy.enabled` lets a cluster whose networking variant ships no Cilium turn the object off. Deny-only with default-deny explicitly disabled, matching the ingress-nginx admission policy: putting these pods behind a default-deny would mean enumerating every port they serve and breaking traffic on the first one forgotten. ### Verification Eight helm-unittest cases cover the port, the all-namespaces span, the absence of any label-based exemption, the world deny, the disabled default-deny, the Cilium kind, the selector and the off switch. The rendered object was additionally accepted by a live API server via `kubectl apply --dry-run=server`, so the CRD validates it as written. Not verified: that a denied pod actually fails to reach the port at runtime. That needs a live negative test against the policy, which is the same gap the ingress-nginx admission policy carries. ### Screenshots Not applicable — no UI change. ### Downstream repositories Walked the trigger map against the diff. Nothing is reached: the change is one chart template, its values and its tests under `packages/system/`, with no package added or removed under `packages/apps/` or `packages/extra/`, no `packages/core/platform/values.yaml` key, no platform variant or bundle change, nothing under `hack/`, and no node prerequisite. - [x] No downstream repository is affected by this change - [ ] [cozystack/website](https://github.com/cozystack/website) - follow-up: - [ ] [cozystack/terraform-provider-cozystack](https://github.com/cozystack/terraform-provider-cozystack) - follow-up: - [ ] [cozystack/ansible-cozystack](https://github.com/cozystack/ansible-cozystack) - follow-up: - [ ] [cozystack/ccp](https://github.com/cozystack/ccp) - follow-up: - [ ] [cozystack/talm](https://github.com/cozystack/talm) - follow-up: - [ ] [cozystack/cozyhr](https://github.com/cozystack/cozyhr) - follow-up: - [ ] [cozystack/cozy-proxy](https://github.com/cozystack/cozy-proxy) - follow-up: - [ ] [cozystack/cozystack-telemetry-server](https://github.com/cozystack/cozystack-telemetry-server) - follow-up: - [ ] [cozystack/external-apps-example](https://github.com/cozystack/external-apps-example) - follow-up: - [ ] [cozystack/examples](https://github.com/cozystack/examples) - follow-up: ### Release note ```release-note fix(kubeovn-webhook): the kube-ovn webhook's serving port is now closed to in-cluster pods and external traffic by a CiliumNetworkPolicy. It previously answered any in-cluster pod with namespace-derived annotations (GHSA-g883-q79m-8225). Disable with webhookPolicy.enabled=false on clusters whose networking variant ships no Cilium. ``` <!-- This is an auto-generated comment: release notes by coderabbit.ai --> ## Summary by CodeRabbit * **New Features** * Added a Cilium network policy to protect the namespace-annotation webhook. * The policy is enabled by default and restricts access to the webhook port, blocking unauthorized in-cluster and external traffic. * Standardized the webhook port across its deployment, service, and network policy configuration. * **Bug Fixes** * Improved webhook network isolation when standard Kubernetes NetworkPolicy enforcement is unavailable. <!-- end of auto-generated comment: release notes by coderabbit.ai -->
Cozystack
Cozystack is a free platform and framework for building clouds.
Cozystack is a CNCF Sandbox Level Project that was originally built and sponsored by Ænix.
With Cozystack, you can transform a bunch of servers into an intelligent system with a simple REST API for spawning Kubernetes clusters, Database-as-a-Service, virtual machines, load balancers, HTTP caching services, and other services with ease.
Use Cozystack to build your own cloud or provide a cost-effective development environment.
Use-Cases
-
Using Cozystack to build a public cloud
You can use Cozystack as a backend for a public cloud -
Using Cozystack to build a private cloud
You can use Cozystack as a platform to build a private cloud powered by Infrastructure-as-Code approach -
Using Cozystack as a Kubernetes distribution
You can use Cozystack as a Kubernetes distribution for Bare Metal
Documentation
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Read the Getting Started section for a quick start.
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