From e0db79a3f10d538e6c596f20b44ff164bba117d1 Mon Sep 17 00:00:00 2001
From: Thore Cimbal <cfx@riot.8shield.net>
Date: Tue, 28 Jul 2026 15:09:29 +0200
Subject: [PATCH] feat: Default-deny ingress NetworkPolicy for authentik
 namespace

Ingress-only default-deny (egress untouched) plus explicit allows:
Traefik (kube-system) + MAS (matrix ns) -> authentik-server on 80/443,
and Traefik -> cert-manager's ACME HTTP-01 solver pods on 8089.
authentik-postgresql already has its own Bitnami-chart-managed policy,
left alone. Part of issue #10.
---
 apps/authentik/kustomization.yaml |  1 +
 apps/authentik/networkpolicy.yaml | 64 +++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 apps/authentik/networkpolicy.yaml

diff --git a/apps/authentik/kustomization.yaml b/apps/authentik/kustomization.yaml
index 860ee7a..c29e79a 100755
--- a/apps/authentik/kustomization.yaml
+++ b/apps/authentik/kustomization.yaml
@@ -8,3 +8,4 @@ resources:
   - certificate.yaml
   - authentik.yaml
   - ingress.yaml
+  - networkpolicy.yaml
diff --git a/apps/authentik/networkpolicy.yaml b/apps/authentik/networkpolicy.yaml
new file mode 100644
index 0000000..96190a8
--- /dev/null
+++ b/apps/authentik/networkpolicy.yaml
@@ -0,0 +1,64 @@
+# Default-deny ingress for the authentik namespace, with explicit allow rules for the
+# traffic paths that actually need to reach in: Traefik (kube-system) for the public
+# auth.axion1337.chat endpoint and ACME HTTP-01 challenges, and MAS (matrix namespace)
+# for upstream OIDC calls. Egress is intentionally untouched (federation-equivalent
+# outbound calls like SMTP aren't restricted here).
+#
+# Note: authentik-postgresql already has its own NetworkPolicy from the Bitnami
+# postgresql subchart (port 5432, no source restriction) - left alone, not duplicated,
+# since it would get reset on the next Helm upgrade anyway.
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: default-deny-ingress
+  namespace: authentik
+spec:
+  podSelector: {}
+  policyTypes:
+    - Ingress
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-ingress-authentik-server
+  namespace: authentik
+spec:
+  podSelector:
+    matchLabels:
+      app.kubernetes.io/name: authentik
+      app.kubernetes.io/component: server
+  policyTypes:
+    - Ingress
+  ingress:
+    - from:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: matrix
+      ports:
+        - protocol: TCP
+          port: 80
+        - protocol: TCP
+          port: 443
+---
+apiVersion: networking.k8s.io/v1
+kind: NetworkPolicy
+metadata:
+  name: allow-ingress-acme-solver
+  namespace: authentik
+spec:
+  podSelector:
+    matchLabels:
+      acme.cert-manager.io/http01-solver: "true"
+  policyTypes:
+    - Ingress
+  ingress:
+    - from:
+        - namespaceSelector:
+            matchLabels:
+              kubernetes.io/metadata.name: kube-system
+      ports:
+        - protocol: TCP
+          port: 8089