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Ingress Access Control

Shows how to set up access control on an ingress gateway.

security

access-control

rbac

authorization

ingress

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 namespace foo with sidecar injection enabled:

{{< text bash >}} $ kubectl create ns foo $ kubectl label namespace foo istio-injection=enabled $ kubectl apply -f @samples/httpbin/httpbin.yaml@ -n foo {{< /text >}}
Expose httpbin through an ingress gateway:

Configure the gateway:

{{< text bash >}} $ kubectl apply -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_PORT and INGRESS_HOST environment variables.

Create the gateway:

{{< text bash >}} $ kubectl apply -f @samples/httpbin/gateway-api/httpbin-gateway.yaml@ -n foo {{< /text >}}

Wait for the gateway to be ready:

{{< text bash >}} $ kubectl wait --for=condition=programmed gtw -n foo httpbin-gateway {{< /text >}}

Turn on RBAC debugging in Envoy for the ingress gateway:

{{< text bash >}} $ kubectl get pods -n foo -o name -l gateway.networking.k8s.io/gateway-name=httpbin-gateway | sed 's|pod/||' | while read -r pod; do istioctl proxy-config log "$pod" -n foo --level rbac:debug; done {{< /text >}}

Set the INGRESS_PORT and INGRESS_HOST environment variables:

{{< text bash >}} export INGRESS_HOST=(kubectl get gtw httpbin-gateway -n foo -o jsonpath='{.status.addresses[0].value}') export INGRESS_PORT=(kubectl get gtw httpbin-gateway -n foo -o jsonpath='{.spec.listeners[?(@.name=="http")].port}') {{< /text >}}

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. The following subsections describe some strategies for preserving the original client IP for logging or security purpose for different load balancer types:

TCP/UDP Proxy Load Balancer
Network Load Balancer
HTTP/HTTPS Load Balancer

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 with an annotation on the gateway service:

{{< 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 >}}

{{< text yaml >}} apiVersion: gateway.networking.k8s.io/v1 kind: Gateway metadata: name: httpbin-gateway annotations: service.beta.kubernetes.io/aws-load-balancer-type: "nlb" spec: gatewayClassName: istio ... {{< /text >}}

TCP/UDP Proxy Load Balancer

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.

Here is a sample configuration that shows how to make an ingress gateway on AWS EKS support the PROXY Protocol:

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

{{< text yaml >}} apiVersion: gateway.networking.k8s.io/v1 kind: Gateway metadata: name: httpbin-gateway annotations: service.beta.kubernetes.io/aws-load-balancer-proxy-protocol: "*" proxy.istio.io/config: '{"gatewayTopology" : { "proxyProtocol": {} }}' spec: gatewayClassName: istio ...

apiVersion: autoscaling/v2 kind: HorizontalPodAutoscaler metadata: name: httpbin-gateway spec: scaleTargetRef: apiVersion: apps/v1 kind: Deployment name: httpbin-gateway-istio minReplicas: 5 maxReplicas: 10 {{< /text >}}

Network Load Balancer

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 use the externalTrafficPolicy: Local setting to also preserve the client IP inside Kubernetes by bypassing kube-proxy and preventing it from sending traffic to other nodes.

{{< warning >}} For production deployments it is strongly recommended to deploy an ingress gateway pod to multiple nodes if you enable externalTrafficPolicy: Local. Otherwise, this creates a situation where only nodes with an active ingress gateway pod will be able to accept and distribute incoming NLB traffic to the rest of the cluster, creating potential ingress traffic bottlenecks and reduced internal load balancing capability, or even complete loss of ingress traffic to the cluster if the subset of nodes with ingress gateway pods go down. See Source IP for Services with Type=NodePort for more information. {{< /warning >}}

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 >}}

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

HTTP/HTTPS Load Balancer

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:

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.

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: ALLOW rules:

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

remoteIpBlocks:

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

ipBlocks:

{{< text bash >}} $ kubectl apply -f - <<EOF apiVersion: security.istio.io/v1 kind: AuthorizationPolicy metadata: name: ingress-policy namespace: foo spec: targetRef: kind: Gateway group: gateway.networking.k8s.io name: httpbin-gateway action: ALLOW rules:

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

remoteIpBlocks:

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

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 >}}
Assign your original client IP address to an env variable. If you don't know it, you can an find it in the Envoy logs using the following command:

ipBlocks:

{{< 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 >}}

remoteIpBlocks:

{{< 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 >}}

ipBlocks:

{{< text bash >}} CLIENT_IP=(kubectl get pods -n foo -o name -l gateway.networking.k8s.io/gateway-name=httpbin-gateway | sed 's|pod/||' | while read -r pod; do kubectl logs "$pod" -n foo | grep remoteIP; done | tail -1 | awk -F, '{print $3}' | awk -F: '{print $2}' | sed 's/ //') && echo "$CLIENT_IP" 192.168.10.15 {{< /text >}}

remoteIpBlocks:

{{< text bash >}} CLIENT_IP=(kubectl get pods -n foo -o name -l gateway.networking.k8s.io/gateway-name=httpbin-gateway | sed 's|pod/||' | while read -r pod; do kubectl logs "$pod" -n foo | grep remoteIP; done | tail -1 | awk -F, '{print $4}' | awk -F: '{print $2}' | sed 's/ //') && echo "$CLIENT_IP" 192.168.10.15 {{< /text >}}

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

ipBlocks:

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

remoteIpBlocks:

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

ipBlocks:

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

remoteIpBlocks:

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

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:

ipBlocks:

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

remoteIpBlocks:

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

ipBlocks:

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

remoteIpBlocks:

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

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 >}}

{{< text bash >}} $ kubectl get pods -n foo -o name -l gateway.networking.k8s.io/gateway-name=httpbin-gateway | sed 's|pod/||' | while read -r pod; do kubectl logs "$pod" -n foo; done {{< /text >}}

Clean up

Remove the authorization policy:

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

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

Remove the namespace foo:

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

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Before you begin

Getting traffic into Kubernetes and Istio

Source IP address of the original client

TCP/UDP Proxy Load Balancer

{{< text yaml >}} apiVersion: gateway.networking.k8s.io/v1 kind: Gateway metadata: name: httpbin-gateway annotations: service.beta.kubernetes.io/aws-load-balancer-proxy-protocol: "*" proxy.istio.io/config: '{"gatewayTopology" : { "proxyProtocol": {} }}' spec: gatewayClassName: istio ...

Network Load Balancer

HTTP/HTTPS Load Balancer

IP-based allow list and deny list

Clean up

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