istio.io/content/en/docs/tasks/security/authorization/authz-ingress/index.md

title	description	weight	keywords	owner	test
Ingress Gateway	Shows how to set up access control on an ingress gateway.	50	security access-control rbac authorization ingress ip allowlist denylist	istio/wg-security-maintainers	yes

This task shows you how to enforce IP-based access control on an Istio ingress gateway using an authorization policy.

Before you begin

Before you begin this task, do the following:

• Read the Istio authorization concepts.

• Install Istio using the Istio installation guide.

• Deploy a workload, httpbin in a namespace, for example foo, and expose it through the Istio ingress gateway with this command:

  {{< text bash >}} $ kubectl create ns foo $ kubectl apply -f <(istioctl kube-inject -f @samples/httpbin/httpbin.yaml@) -n foo $ kubectl apply -f <(istioctl kube-inject -f @samples/httpbin/httpbin-gateway.yaml@) -n foo {{< /text >}}

• Turn on RBAC debugging in Envoy for the ingress gateway:

  {{< text bash >}} $ kubectl get pods -n istio-system -o name -l istio=ingressgateway | sed 's|pod/||' | while read -r pod; do istioctl proxy-config log "$pod" -n istio-system --level rbac:debug; done {{< /text >}}

• Follow the instructions in Determining the ingress IP and ports to define the INGRESS_HOST and INGRESS_PORT environment variables.

• Verify that the httpbin workload and ingress gateway are working as expected using this command:

  {{< text bash >}} $ curl "$INGRESS_HOST:$INGRESS_PORT"/headers -s -o /dev/null -w "%{http_code}\n" 200 {{< /text >}}

{{< warning >}} If you don’t see the expected output, retry after a few seconds. Caching and propagation overhead can cause a delay. {{< /warning >}}

Getting traffic into Kubernetes and Istio

All methods of getting traffic into Kubernetes involve opening a port on all worker nodes. The main features that accomplish this are the NodePort service and the LoadBalancer service. Even the Kubernetes Ingress resource must be backed by an Ingress controller that will create either a NodePort or a LoadBalancer service.

• A NodePort just opens up a port in the range 30000-32767 on each worker node and uses a label selector to identify which Pods to send the traffic to. You have to manually create some kind of load balancer in front of your worker nodes or use Round-Robin DNS.

• A LoadBalancer is just like a NodePort, except it also creates an environment specific external load balancer to handle distributing traffic to the worker nodes. For example, in AWS EKS, the LoadBalancer service will create a Classic ELB with your worker nodes as targets. If your Kubernetes environment does not have a LoadBalancer implementation, then it will just behave like a NodePort. An Istio ingress gateway creates a LoadBalancer service.

What if the Pod that is handling traffic from the NodePort or LoadBalancer isn't running on the worker node that received the traffic? Kubernetes has its own internal proxy called kube-proxy that receives the packets and forwards them to the correct node.

Source IP address of the original client

If a packet goes through an external proxy load balancer and/or kube-proxy, then the original source IP address of the client is lost. Below are some strategies for preserving the original client IP for logging or security purposes.

{{< tabset category-name="lb" >}}

{{< tab name="TCP/UDP Proxy Load Balancer" category-value="proxy" >}}

If you are using a TCP/UDP Proxy external load balancer (AWS Classic ELB), it can use the Proxy Protocol to embed the original client IP address in the packet data. Both the external load balancer and the Istio ingress gateway must support the proxy protocol for it to work. In Istio, you can enable it with an EnvoyFilter like below:

{{< text yaml >}} apiVersion: networking.istio.io/v1alpha3 kind: EnvoyFilter metadata: name: proxy-protocol namespace: istio-system spec: configPatches:

• applyTo: LISTENER patch: operation: MERGE value: listener_filters: - name: envoy.listener.proxy_protocol - name: envoy.listener.tls_inspector workloadSelector: labels: istio: ingressgateway {{< /text >}}

Here is a sample of the IstioOperator that shows how to configure the Istio ingress gateway on AWS EKS to support the Proxy Protocol:

{{< text yaml >}} apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: meshConfig: accessLogEncoding: JSON accessLogFile: /dev/stdout components: ingressGateways: - enabled: true k8s: hpaSpec: maxReplicas: 10 minReplicas: 5 serviceAnnotations: service.beta.kubernetes.io/aws-load-balancer-access-log-emit-interval: "5" service.beta.kubernetes.io/aws-load-balancer-access-log-enabled: "true" service.beta.kubernetes.io/aws-load-balancer-access-log-s3-bucket-name: elb-logs service.beta.kubernetes.io/aws-load-balancer-access-log-s3-bucket-prefix: k8sELBIngressGW service.beta.kubernetes.io/aws-load-balancer-proxy-protocol: "*" affinity: podAntiAffinity: preferredDuringSchedulingIgnoredDuringExecution: - podAffinityTerm: labelSelector: matchLabels: istio: ingressgateway topologyKey: failure-domain.beta.kubernetes.io/zone weight: 1 name: istio-ingressgateway {{< /text >}}

{{< /tab >}}

{{< tab name="Network Load Balancer" category-value="network" >}}

If you are using a TCP/UDP network load balancer that preserves the client IP address (AWS Network Load Balancer, GCP External Network Load Balancer, Azure Load Balancer) or you are using Round-Robin DNS, then you can also preserve the client IP inside Kubernetes by bypassing kube-proxy and preventing it from sending traffic to other nodes. However, you must run an ingress gateway pod on every node. If you don't, then any node that receives traffic and doesn't have an ingress gateway will drop the traffic. See Source IP for Services with Type=NodePort for more information. Update the ingress gateway to set externalTrafficPolicy: Local to preserve the original client source IP on the ingress gateway using the following command:

{{< text bash >}} $ kubectl patch svc istio-ingressgateway -n istio-system -p '{"spec":{"externalTrafficPolicy":"Local"}}' {{< /text >}}

{{< /tab >}}

{{< tab name="HTTP/HTTPS Load Balancer" category-value="http" >}}

If you are using an HTTP/HTTPS external load balancer (AWS ALB, GCP ), it can put the original client IP address in the X-Forwarded-For header. Istio can extract the client IP address from this header with some configuration. See Configuring Gateway Network Topology. Quick example if using a single load balancer in front of Kubernetes:

{{< text yaml >}} apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: meshConfig: accessLogEncoding: JSON accessLogFile: /dev/stdout defaultConfig: gatewayTopology: numTrustedProxies: 1 {{< /text >}}

{{< /tab >}}

{{< /tabset >}}

For reference, here are the types of load balancers created by Istio with a LoadBalancer service on popular managed Kubernetes environments:

Cloud Provider	Load Balancer Name	Load Balancer Type
AWS EKS	Classic Elastic Load Balancer	TCP Proxy
GCP GKE	TCP/UDP Network Load Balancer	Network
Azure AKS	Azure Load Balancer	Network
IBM IKS/ROKS	Network Load Balancer	Network
DO DOKS	Load Balancer	Network

{{< tip >}} You can instruct AWS EKS to create a Network Load Balancer when you install Istio by using a serviceAnnotation like below:

{{< text yaml >}} apiVersion: install.istio.io/v1alpha1 kind: IstioOperator spec: meshConfig: accessLogEncoding: JSON accessLogFile: /dev/stdout components: ingressGateways: - enabled: true k8s: hpaSpec: maxReplicas: 10 minReplicas: 5 serviceAnnotations: service.beta.kubernetes.io/aws-load-balancer-type: "nlb" {{< /text >}}

{{< /tip >}}

IP-based allow list and deny list

When to use ipBlocks vs. remoteIpBlocks: If you are using the X-Forwarded-For HTTP header or the Proxy Protocol to determine the original client IP address, then you should use remoteIpBlocks in your AuthorizationPolicy. If you are using externalTrafficPolicy: Local, then you should use ipBlocks in your AuthorizationPolicy.

Load Balancer Type	Source of Client IP	ipBlocks vs. remoteIpBlocks
TCP Proxy	Proxy Protocol	remoteIpBlocks
Network	packet source address	ipBlocks
HTTP/HTTPS	X-Forwarded-For	remoteIpBlocks

• The following command creates the authorization policy, ingress-policy, for the Istio ingress gateway. The following policy sets the action field to ALLOW to allow the IP addresses specified in the ipBlocks to access the ingress gateway. IP addresses not in the list will be denied. The ipBlocks supports both single IP address and CIDR notation.

{{< tabset category-name="source" >}}

{{< tab name="ipBlocks" category-value="ipBlocks" >}}

Create the AuthorizationPolicy:

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: istio-system spec: selector: matchLabels: app: istio-ingressgateway action: ALLOW rules:

• from:
  • source: ipBlocks: ["1.2.3.4", "5.6.7.0/24"] EOF {{< /text >}}

{{< /tab >}}

{{< tab name="remoteIpBlocks" category-value="remoteIpBlocks" >}}

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: istio-system spec: selector: matchLabels: app: istio-ingressgateway action: ALLOW rules:

• from:
  • source: remoteIpBlocks: ["1.2.3.4", "5.6.7.0/24"] EOF {{< /text >}}

{{< /tab >}}

{{< /tabset >}}

• Verify that a request to the ingress gateway is denied:

  {{< text bash >}} $ curl "$INGRESS_HOST:$INGRESS_PORT"/headers -s -o /dev/null -w "%{http_code}\n" 403 {{< /text >}}

• Update the ingress-policy to include your client IP address:

{{< tabset category-name="source" >}}

{{< tab name="ipBlocks" category-value="ipBlocks" >}}

Find your original client IP address if you don't know it and assign it to a variable:

{{< text bash >}} CLIENT_IP=(kubectl get pods -n istio-system -o name -l istio=ingressgateway | sed 's|pod/||' | while read -r pod; do kubectl logs "$pod" -n istio-system | grep remoteIP; done | tail -1 | awk -F, '{print $3}' | awk -F: '{print $2}' | sed 's/ //') && echo "$CLIENT_IP" 192.168.10.15 {{< /text >}}

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: istio-system spec: selector: matchLabels: app: istio-ingressgateway action: ALLOW rules:

• from:
  • source: ipBlocks: ["1.2.3.4", "5.6.7.0/24", "$CLIENT_IP"] EOF {{< /text >}}

{{< /tab >}}

{{< tab name="remoteIpBlocks" category-value="remoteIpBlocks" >}}

Find your original client IP address if you don't know it and assign it to a variable:

{{< text bash >}} CLIENT_IP=(kubectl get pods -n istio-system -o name -l istio=ingressgateway | sed 's|pod/||' | while read -r pod; do kubectl logs "$pod" -n istio-system | grep remoteIP; done | tail -1 | awk -F, '{print $4}' | awk -F: '{print $2}' | sed 's/ //') && echo "$CLIENT_IP" 192.168.10.15 {{< /text >}}

Create the AuthorizationPolicy:

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: istio-system spec: selector: matchLabels: app: istio-ingressgateway action: ALLOW rules:

• from:
  • source: remoteIpBlocks: ["1.2.3.4", "5.6.7.0/24", "$CLIENT_IP"] EOF {{< /text >}}

{{< /tab >}}

{{< /tabset >}}

• Verify that a request to the ingress gateway is allowed:

  {{< text bash >}} $ curl "$INGRESS_HOST:$INGRESS_PORT"/headers -s -o /dev/null -w "%{http_code}\n" 200 {{< /text >}}

• Update the ingress-policy authorization policy to set the action key to DENY so that the IP addresses specified in the ipBlocks are not allowed to access the ingress gateway:

{{< tabset category-name="source" >}}

{{< tab name="ipBlocks" category-value="ipBlocks" >}}

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: istio-system spec: selector: matchLabels: app: istio-ingressgateway action: DENY rules:

• from:
  • source: ipBlocks: ["$CLIENT_IP"] EOF {{< /text >}}

{{< /tab >}}

{{< tab name="remoteIpBlocks" category-value="remoteIpBlocks" >}}

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: istio-system spec: selector: matchLabels: app: istio-ingressgateway action: DENY rules:

• from:
  • source: remoteIpBlocks: ["$CLIENT_IP"] EOF {{< /text >}}

{{< /tab >}}

{{< /tabset >}}

• Verify that a request to the ingress gateway is denied:

  {{< text bash >}} $ curl "$INGRESS_HOST:$INGRESS_PORT"/headers -s -o /dev/null -w "%{http_code}\n" 403 {{< /text >}}

• You could use an online proxy service to access the ingress gateway using a different client IP to verify the request is allowed.

• If you are not getting the responses you expect, view the ingress gateway logs which should show RBAC debugging information:

  {{< text bash >}} $ kubectl get pods -n istio-system -o name -l istio=ingressgateway | sed 's|pod/||' | while read -r pod; do kubectl logs "$pod" -n istio-system; done {{< /text >}}

Clean up

• Remove the namespace foo:

  {{< text bash >}} $ kubectl delete namespace foo {{< /text >}}

• Remove the authorization policy:

  {{< text bash >}} $ kubectl delete authorizationpolicy ingress-policy -n istio-system {{< /text >}}