Homelabv4/infrastructure/istio/manifests/mesh/authorization-policies.yaml

# ==========================================================================
# Zero Trust Authorization Policies - Deny by Default, Allow Explicitly
# ==========================================================================
#
# Policy hierarchy:
#   1. Mesh-wide DENY (default - everything blocked)
#   2. Ingress Gateway ALLOW (external traffic entry point)
#   3. Service-to-service ALLOW (explicit inter-service communication)
#   4. Monitoring ALLOW (Prometheus scraping, Kiali queries)
#
# In ambient mode, L7 policies are enforced by waypoint proxies in each
# namespace. L4 policies (source namespace/principal) are enforced by ztunnel.
# Each namespace with ALLOW/CUSTOM policies must have a waypoint Gateway.
# ==========================================================================

# --- Ingress Gateway: Allow all external traffic through the edge gateway ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-ingress-gateway
  namespace: istio-system
spec:
  selector:
    matchLabels:
      istio: ingressgateway
  action: ALLOW
  rules:
    - {}

---
# --- Allow Prometheus to scrape Istio control plane + gateway metrics ---
# Selector scopes this to istio-system workloads only.
# Without a selector, policies in the root namespace (istio-system) apply
# mesh-wide in ambient mode, creating implicit deny for all ambient workloads.
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-prometheus-scraping
  namespace: istio-system
spec:
  selector:
    matchLabels:
      app.kubernetes.io/part-of: istio
  action: ALLOW
  rules:
    - from:
        - source:
            namespaces:
              - prometheus
      to:
        - operation:
            ports:
              - "15014"  # istiod control plane metrics
              - "15020"  # sidecar/gateway merged metrics
              - "15090"  # Envoy admin metrics

---
# --- Allow Kiali to query istiod ---
# Selector scopes this to istiod only (ambient root namespace caveat above).
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-kiali
  namespace: istio-system
spec:
  selector:
    matchLabels:
      app: istiod
  action: ALLOW
  rules:
    - from:
        - source:
            principals:
              - cluster.local/ns/istio-system/sa/kiali-service-account

---
# --- Authentik: Allow traffic from ingress + apps doing OIDC ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-authentik-access
  namespace: authentik
spec:
  action: ALLOW
  rules:
    # Intra-namespace (server ↔ worker ↔ postgres)
    - from:
        - source:
            namespaces:
              - authentik
    # CNPG operator managing database instances
    - from:
        - source:
            namespaces:
              - cnpg-system
    # Ingress gateway for browser flows
    - from:
        - source:
            namespaces:
              - istio-system
    # Apps doing OIDC token exchange
    - from:
        - source:
            namespaces:
              - argocd
              - gitlab
              - grafana
              - nextcloud
              - home-assistant
              - guacamole
              - netbird
              - cattle-system
              - frigate
              - teslamate
    # Prometheus scraping (L4-only; L7 path checks deferred to waypoint)
    - from:
        - source:
            namespaces:
              - prometheus

---
# --- Grafana: Allow ingress + Prometheus datasource queries + scraping ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-grafana-access
  namespace: grafana
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - grafana
    - from:
        - source:
            namespaces:
              - istio-system
    - from:
        - source:
            namespaces:
              - prometheus
    # NetBird VPN cluster routers (non-mesh, use ipBlocks)
    - from:
        - source:
            ipBlocks:
              - "10.244.0.0/16"

---
# --- Prometheus: Allow ingress + self-scraping + Grafana ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-prometheus-access
  namespace: prometheus
spec:
  action: ALLOW
  rules:
    # Intra-namespace (Prometheus ↔ alertmanager ↔ node-exporter)
    - from:
        - source:
            namespaces:
              - prometheus
    - from:
        - source:
            namespaces:
              - istio-system
              - grafana
    # NetBird VPN cluster routers (non-mesh, use ipBlocks)
    - from:
        - source:
            ipBlocks:
              - "10.244.0.0/16"

---
# --- MQTT: Allow Home Assistant + Frigate + ESPHome + Prometheus ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-mqtt-access
  namespace: mqtt
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - mqtt
    - from:
        - source:
            namespaces:
              - istio-system
              - home-assistant
              - frigate
              - teslamate
    # Prometheus scraping (L4-only; L7 path checks deferred to waypoint)
    - from:
        - source:
            namespaces:
              - prometheus

---
# --- External DNS: Allow internal access + Prometheus ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-external-dns
  namespace: external-dns
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - external-dns
    - from:
        - source:
            namespaces:
              - istio-system
    # Prometheus scraping (L4-only; L7 path checks deferred to waypoint)
    - from:
        - source:
            namespaces:
              - prometheus

---
# --- Unpoller: Allow Prometheus scraping ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-unpoller-access
  namespace: unpoller
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - unpoller
    # Prometheus scraping (L4-only; L7 path checks deferred to waypoint)
    - from:
        - source:
            namespaces:
              - prometheus

---
# --- Netbird: Allow ingress + Prometheus ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-netbird-access
  namespace: netbird
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - netbird
    # CNPG operator managing database instances
    - from:
        - source:
            namespaces:
              - cnpg-system
    - from:
        - source:
            namespaces:
              - istio-system
    # Netbird operator querying management API
    - from:
        - source:
            namespaces:
              - netbird-operator
    - from:
        - source:
            namespaces:
              - prometheus

---
# --- Netbird Operator: Allow intra-namespace + Prometheus ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-netbird-operator-access
  namespace: netbird-operator
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - netbird-operator
    # Prometheus scraping (L4-only)
    - from:
        - source:
            namespaces:
              - prometheus

---
# --- CrowdSec: Allow intra-namespace + CNPG + Prometheus ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-crowdsec-access
  namespace: crowdsec
spec:
  action: ALLOW
  rules:
    # Intra-namespace (LAPI <-> agent)
    - from:
        - source:
            namespaces:
              - crowdsec
    # CNPG operator managing database instances
    - from:
        - source:
            namespaces:
              - cnpg-system
    # Prometheus scraping (L4-only; L7 path checks deferred to waypoint)
    - from:
        - source:
            namespaces:
              - prometheus
    # Firewall bouncer (hostNetwork DaemonSet) connects from node IPs
    - from:
        - source:
            ipBlocks:
              - "172.28.101.0/24"

---
# --- Scylla Manager: Allow ingress + Prometheus + intra-namespace ---
apiVersion: security.istio.io/v1
kind: AuthorizationPolicy
metadata:
  name: allow-scylla-manager-access
  namespace: scylla-manager
spec:
  action: ALLOW
  rules:
    # Intra-namespace
    - from:
        - source:
            namespaces:
              - scylla-manager
    - from:
        - source:
            namespaces:
              - istio-system
    - from:
        - source:
            namespaces:
              - prometheus
    # Scylla operator managing clusters
    - from:
        - source:
            namespaces:
              - scylla-operator