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feat(ingress-nginx): bump to 1.11.5 and restrict the admission webhook - #3798

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feat(ingress-nginx): bump to 1.11.5 and restrict the admission webhook#3798
Andrei Kvapil (kvaps) wants to merge 4 commits into
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feat/ingress-nginx-1.11.5

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@kvaps Andrei Kvapil (kvaps) commented Aug 13, 2026

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What this PR does

Bumps ingress-nginx to chart 4.11.5 / controller v1.11.5, and closes the admission webhook to everything except the API server.

Version bump

The shipped v1.11.2 controller is a cozystack rebuild that already carries a backport of the CVE-2025-1974 fix (v0.28.2, March 2025), so this is not a fix for a live vulnerability. The problem is that it reports itself as a plain v1.11.2 build git-d3bb2b4: the binary is built from the upstream 1.11.2 tag with the patch applied on top, which does not change the version ldflags, and the image labels are inherited from the registry.k8s.io base layer. A patched build is therefore indistinguishable from an unpatched one by anything except its digest, and anything scanning by version string flags it. This bump removes that ambiguity.

packages/system/ingress-nginx feeds three consumers — the platform ingress, tenant Ingress applications (extra/ingress), and the ingress addon of tenant Kubernetes clusters — so one bump covers all three. The protobuf-exporter sidecar moves in lockstep, since its tag tracks the upstream controller version.

CHART_VERSION is now pinned in the package Makefile. helm pull carried no --version, so make update would have fetched whatever is latest upstream (4.13.9 today) against a controller image that only exists for selected versions.

Admission webhook policy

The webhook is only ever called by the API server, but it was reachable from every pod in the cluster, in any namespace — avoidable attack surface independent of any specific CVE.

The new CiliumNetworkPolicy is deny-only and disables default-deny. A Cilium rule carrying an ingress section otherwise puts the selected endpoints behind a default-deny, which here would mean enumerating every port the controller serves (80, 443, metrics, the exporter, tcp/udp services) and breaking traffic on the first one missed. Subtracting one port is the safer construction.

Two callers are deliberately not denied:

  • host-network sources, which are not Cilium endpoints — this covers a management cluster, where the API server runs on the host network;
  • the konnectivity agent, which is not optional. On a Kamaji-hosted tenant cluster the API server lives outside the cluster and reaches in-cluster webhooks through the konnectivity tunnel (Kamaji defines only the cluster egress selection), so the call arrives from the agent pod in kube-system, not from the API server address. A fromEntities: [kube-apiserver] allow would not match it, and every Ingress create/update in every tenant cluster would start failing.

The policy is namespaced rather than clusterwide on purpose: the same package is installed into several namespaces of one cluster, so a cluster-scoped object with a fixed name would collide between releases. It can be disabled with admissionWebhookPolicy.enabled.

Verification

Tested on a live Kamaji tenant cluster (k8s 1.35.6, Cilium 1.19), with the addon enabled for the test and disabled afterwards:

probe from a pod in default Ingress create
without policy open works
with policy Connection timed out works

Also confirmed on the management cluster that kube-apiserver runs as static pods on the host network, so the host-network carve-out holds there.

The package previously ran no unit tests at all; a test target is added with 7 assertions covering the policy. It is scoped with --with-subchart=false because the vendored chart carries upstream's own suites, which assert upstream defaults and fail under our values. The full hack/helm-unit-tests.sh sweep is green.

The controller and exporter images are rebuilt by cozystack/ingress-nginx-with-protobuf-exporter#5, which vendors the 11843.diff patch instead of fetching it from a still-open upstream PR at build time.

Screenshots

Not applicable — no UI changes.

Downstream repositories

Walked the trigger map in docs/agents/contributing.md against the diff, which touches packages/system/ingress-nginx/ and one comment line in hack/promote-retag.sh:

  • website — no package added, renamed or removed under apps//extra/; no platform component added or removed; no change to packages/core/platform/values.yaml, variants, bundles or release assets. The package Makefiles trigger was considered because of CHART_VERSION and the new test target: CHART_VERSION does not change the documented contract of make update, and test: helm unittest is an existing pattern in the repo (packages/system/cilium-networkpolicy/Makefile), not new tooling.
  • terraform-provider-cozystack — every trigger is about packages/apps/, values.schema.json, version enums or ApplicationDefinition; none apply to a system package.
  • ansible-cozystack — no change to installer values, platform keys the role sets, variants, waited-on objects or node prerequisites.
  • ccphack/package.mk and hack/common-envs.mk untouched; nothing under hack/ moved or renamed, and the edit to hack/promote-retag.sh is a comment with no behaviour change; layout and namespaces unchanged.
  • external-apps-example, talm, cozyhr, cozy-proxy, cozystack-telemetry-server, examples — no trigger matches.

Release note

feat(ingress-nginx): update to chart 4.11.5 with controller v1.11.5, and restrict the admission webhook so it is reachable only by the API server. The previously shipped v1.11.2 image already contained a backport of the CVE-2025-1974 fix; it reported itself as a stock v1.11.2 build, which this update makes unambiguous.

Summary by CodeRabbit

  • New Features

    • Added optional network protection for the admission webhook with restricted access rules.
    • Added PrometheusRule support and improved ServiceMonitor configuration for monitoring integrations.
    • Webhook service ports are now configurable.
  • Updates

    • Upgraded ingress-nginx and controller images to version 4.11.5.
    • Improved default-backend availability handling and topology-spread settings.
    • Added Pod Security Admission guidance and refreshed configuration documentation.
  • Bug Fixes

    • Corrected webhook service rendering and default-backend disruption budget behavior.

Andrei Kvapil (kvaps) and others added 3 commits August 12, 2026 18:16
…pace

The sidecar was still referenced from an individual maintainer's namespace
while the controller beside it, built from the same repository and pinned to
the same version, already came from the project's. The repository moved to the
cozystack organisation some time ago; the image reference did not follow.

Same image: the digest is unchanged, and v1.11.2 is kept so the sidecar stays
aligned with the controller, whose tag tracks the upstream ingress-nginx
version.

Assisted-By: Claude
Signed-off-by: Andrei Kvapil <kvapss@gmail.com>
The controller image is a cozystack rebuild that adds the protobuf
exporter, so the chart must not drift ahead of the tags published under
ghcr.io/cozystack/ingress-nginx-with-protobuf-exporter. Pin the chart
version in the Makefile: helm pull carried no --version and would
otherwise fetch whatever is latest upstream.

The v1.11.2 image already carried a backport of the upstream security
patches, but it reports itself as a plain v1.11.2 build, which makes it
indistinguishable from an unpatched build for anyone scanning by version
string. Moving to a stock v1.11.5 removes that ambiguity.

The protobuf-exporter sidecar is bumped in lockstep so the two stay on
the same upstream version.

Assisted-By: Claude
Signed-off-by: Andrei Kvapil <andrei.kvapil@aenix.io>
The admission webhook is only ever called by the API server, but it was
reachable from every pod in the cluster, in any namespace. That is
avoidable attack surface: any flaw in the webhook becomes exploitable by
any workload, which is what separated CVE-2025-1974 from an ordinary
webhook bug.

The rule is deny-only and disables default-deny. Any Cilium rule with an
ingress section otherwise puts the selected endpoints behind a
default-deny, which here would mean enumerating every port the
controller serves and breaking traffic on the first one missed.

Host-network sources are not Cilium endpoints, so a management cluster's
API server is unaffected. Tenant clusters need an explicit carve-out
instead: Kamaji places the API server outside the cluster and defines
only the "cluster" egress selection, so webhook calls arrive from the
konnectivity agent pod rather than from the API server address, and
denying it would fail every Ingress create/update in the tenant cluster.

Assisted-By: Claude
Signed-off-by: Andrei Kvapil <andrei.kvapil@aenix.io>
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  • packages/system/ingress-nginx/templates/admission-webhook-networkpolicy.yaml
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📝 Walkthrough

Walkthrough

The ingress-nginx chart is upgraded to 4.11.5. The update refreshes images, templates, CI values, Helm tests, documentation, and admission webhook network policy configuration.

Changes

Ingress-nginx chart update

Layer / File(s) Summary
Chart release and configuration
packages/system/ingress-nginx/Makefile, packages/system/ingress-nginx/charts/ingress-nginx/*, packages/system/ingress-nginx/values.yaml, packages/system/ingress-nginx/README.md
Pins chart version 4.11.5, updates image references and chart metadata, adds Helm test execution, and documents Pod Security Admission settings.
Helm CI value coverage
packages/system/ingress-nginx/charts/ingress-nginx/ci/*
Refreshes controller workload, service, image, metrics, ingress class, header, extra-module, and cert-manager test values.
Chart template behavior
packages/system/ingress-nginx/charts/ingress-nginx/templates/*
Adds PrometheusRule rendering, makes webhook ports configurable, updates ServiceMonitor rendering, and refines default-backend PDB and ServiceAccount templates.
Chart rendering tests
packages/system/ingress-nginx/charts/ingress-nginx/tests/*
Adds coverage for webhook resources, image composition, ConfigMap values, PDB conditions, PrometheusRule, ServiceMonitor, and ServiceAccount rendering.
Admission webhook network policy
packages/system/ingress-nginx/templates/admission-webhook-networkpolicy.yaml, packages/system/ingress-nginx/tests/admission_webhook_networkpolicy_test.yaml, packages/system/ingress-nginx/values.yaml
Adds an optional CiliumNetworkPolicy that restricts admission webhook traffic and tests its rendered rules and disabled state.

Retag comment cleanup

Layer / File(s) Summary
Third-party image comment
hack/promote-retag.sh
Removes the kvaps registry path from the exclusion comment. No executable behavior changes.

Estimated code review effort: 4 (Complex) | ~45 minutes

Merge Risk: ⚪ Minimal · up to 8554c

The version and webhook-policy changes are merge-ready after normal checks and review; no actionable merge-blocking risk remains.

Suggested reviewers: ivanhunters

🚥 Pre-merge checks | ✅ 5
✅ Passed checks (5 passed)
Check name Status Explanation
Description Check ✅ Passed Check skipped - CodeRabbit’s high-level summary is enabled.
Title check ✅ Passed The title clearly and concisely summarizes the ingress-nginx version upgrade and admission webhook restriction, which are the main changes.
Docstring Coverage ✅ Passed No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0 files. (2 skipped: 2 unsupported.)
Linked Issues check ✅ Passed Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check ✅ Passed Check skipped because no linked issues were found for this pull request.
✨ Finishing Touches
🧪 Generate unit tests (beta)
  • Create PR with unit tests
  • Commit unit tests in branch feat/ingress-nginx-1.11.5

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents
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Inline comments:
In
`@packages/system/ingress-nginx/templates/admission-webhook-networkpolicy.yaml`:
- Around line 51-62: Update the fromEndpoints selector in the admission webhook
NetworkPolicy so the konnectivity-agent exemption applies only within the
kube-system namespace; require namespace kube-system for allowed endpoints and
retain the k8s-app=konnectivity-agent constraint. Add or update a test covering
rejection of matching labels outside kube-system and non-matching labels within
kube-system.
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📥 Commits

Reviewing files that changed from the base of the PR and between 09dc7f4 and 629deec.

📒 Files selected for processing (74)
  • hack/promote-retag.sh
  • packages/system/ingress-nginx/Makefile
  • packages/system/ingress-nginx/charts/ingress-nginx/Chart.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/OWNERS
  • packages/system/ingress-nginx/charts/ingress-nginx/README.md
  • packages/system/ingress-nginx/charts/ingress-nginx/README.md.gotmpl
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/admission-webhooks-cert-manager-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/controller-admission-tls-cert-manager-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/controller-configmap-addheaders-values.yaml
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  • packages/system/ingress-nginx/charts/ingress-nginx/ci/controller-custom-ingressclass-flags.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/controller-daemonset-extra-modules-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/controller-daemonset-metrics-values.yaml
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  • packages/system/ingress-nginx/charts/ingress-nginx/templates/_helpers.tpl
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  • packages/system/ingress-nginx/charts/ingress-nginx/ci/daemonset-headers-values.yaml
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  • packages/system/ingress-nginx/charts/ingress-nginx/ci/daemonset-tcp-udp-configMapNamespace-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/controller-admission-tls-cert-manager-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/deployment-tcp-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/deployment-extra-modules.yaml
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  • packages/system/ingress-nginx/charts/ingress-nginx/ci/deployment-internal-lb-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/deployment-autoscaling-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/deployment-nodeport-values.yaml
  • packages/system/ingress-nginx/charts/ingress-nginx/ci/deployment-tcp-udp-configMapNamespace-values.yaml
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  • packages/system/ingress-nginx/charts/ingress-nginx/OWNERS
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@github-actions github-actions Bot added area/networking Issues or PRs related to networking (ingress, gateway, vpn, metallb, kube-ovn) kind/feature Categorizes issue or PR as related to a new feature size/L This PR changes 100-499 lines, ignoring generated files labels Aug 13, 2026

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Blocker is the k8s-app: konnectivity-agent carve-out. k8s-app is ordinary pod label, any workload sets it on itself, and with enableDefaultDeny.ingress: false and no ingress section, falling out of that deny is whole access decision. So any pod in any namespace reaches webhook port by putting that label on itself, which is what policy is meant to stop. Nothing in repo constrains pod labels by admission, and label really is identity-relevant in cilium 1.19.5 (pkg/labelsfilter/filter.go has no default whitelist), so it is not filtered out.

Namespace key is not forgeable. Splitting the deny in two would keep the carve-out and close this: one entry for k8s:io.kubernetes.pod.namespace NotIn [kube-system] with no label condition, one for namespace In [kube-system] with current NotIn on k8s-app. Then only agent in kube-system is exempt.

I checked kamaji at pinned 26.3.6-edge and label is right, internal/resources/konnectivity/agent.go sets k8s-app: konnectivity-agent and nothing else on pod template, so carve-out matches what you intended.

I only looked at 4 non-vendored files, not the chart refresh.

- matchExpressions:
- key: k8s:io.kubernetes.pod.namespace
operator: Exists
- key: k8s-app

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k8s-app is ordinary pod label, any workload can set it. With enableDefaultDeny.ingress: false above, falling out of this deny is the whole access decision, so a pod in any namespace gets to webhook port just by labelling itself k8s-app: konnectivity-agent. Namespace key is not forgeable, so two deny entries instead of one would fix it - namespace NotIn [kube-system] with no label condition, and namespace In [kube-system] with this NotIn kept.

- port: {{ $webhookPort | quote }}
protocol: TCP
- fromEntities:
- world

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This may deny apiserver itself. In cilium 1.19.5 an out-of-cluster apiserver CIDR identity can carry both reserved:kube-apiserver and reserved:world, resolveLabels() in pkg/ipcache/metadata.go leaves HasKubeAPIServerLabel() out of isInCluster and then adds world, and appendAPIServerLabelsForDeletion guards on exactly that pair. Deny wins over allow, so no fromEntities: [kube-apiserver] allow could rescue it later.

Both topologies we ship are carved out anyway (in-cluster apiserver is host network, external control plane comes through worker nodes without original source IP), so nothing is broken today. But webhook Service is ClusterIP with no override, so I am not sure what this rule buys against that risk. Read from source, i did not test on cluster.

The admission-webhook deny exempted any endpoint carrying
k8s-app: konnectivity-agent, in any namespace. Because the rule
disables default-deny, falling out of the deny is the entire access
decision — so any pod anywhere could reach the webhook port by
labelling itself, which is precisely the access the policy exists to
remove.

k8s-app is an ordinary pod label a workload sets on itself. Nothing in
the platform constrains pod labels by admission, and Cilium keeps
k8s-app identity-relevant (its label filter ships no default
whitelist), so the forged label really does change the endpoint's
identity rather than being filtered out.

The namespace key is derived by Cilium from the pod's actual namespace
and cannot be set by the workload. Splitting the deny in two keeps the
carve-out and closes the hole: one selector for everything outside
kube-system with no label condition at all, one for kube-system
carrying the existing NotIn. Only the agent in its own namespace is
exempt.

Kamaji at the pinned 26.3.6-edge puts nothing but
k8s-app: konnectivity-agent on the agent pod template
(internal/resources/konnectivity/agent.go), so the label remains the
only available discriminator and the namespace confinement is what
makes it safe to key on.

Tests cover both halves: the outside-kube-system selector must carry no
label condition, and the kube-system selector must keep exactly the
namespace and label pair.

Reported-by: Daniil Myasnikov <myasnikovdaniil2001@gmail.com>
Assisted-By: Claude
Signed-off-by: Andrei Kvapil <andrei.kvapil@aenix.io>
@kvaps

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Applied exactly as you proposed — the deny is now two selectors that OR together: everything outside kube-system with no label condition at all, and inside kube-system the existing NotIn on k8s-app. Only the agent in its own namespace is exempt.

You're right that this was the whole access decision rather than a hardening detail. With enableDefaultDeny.ingress: false and no ingress section, falling out of the deny is being allowed, so a label carve-out spanning every namespace meant any pod anywhere could reach :8443 by labelling itself.

I re-checked the three things the fix rests on rather than taking them on faith. Nothing in the platform constrains pod labels by admission, so the label is freely settable. Cilium keeps k8s-app identity-relevant — pkg/labelsfilter/filter.go ships no default whitelist, so a forged label genuinely changes the endpoint's identity rather than being dropped. And Kamaji at the pinned 26.3.6-edge sets nothing but k8s-app: konnectivity-agent on the agent pod template (internal/resources/konnectivity/agent.go), so the label stays the only discriminator available — which is why confining it by namespace is the fix rather than picking a more specific label.

Tests cover both halves, since the interesting property here is an absence: the outside-kube-system selector must carry no label condition (asserted by expression count plus an explicit notContains), and the kube-system selector must keep exactly the namespace/label pair. The previous test asserted operator: Exists on the namespace key, which the split makes wrong, so it was rewritten.

CodeRabbit flagged the same thing independently on this file, which is a fair signal it was findable rather than exotic. Good catch before it shipped.

One thing from your last line stays open: the chart refresh really is unreviewed. The vendored charts/ingress-nginx/ now carries upstream's own test suites, which the package's test: target skips via --with-subchart=false because they assert against upstream defaults rather than ours — so they are inert here, but that also means nothing in CI reads them. If you have appetite for a second pass, that diff and the two files in patches/ are where the remaining risk sits.

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