IP-auth

This repository contains an early prototype, and is not meant to be used in the production use case. Feel free to try it out, leave feedback, and report issues.

Status

Overview

IP-auth is an external authorizer for Istio Ingress Gateway. It is a simple service that checks if the request's IP address is not in a list of blocked IP ranges. If the IP address is not in the list, the service returns a 200 OK response. If the IP address is in the list, the service returns a 403 Forbidden response.

The list of blocked IP ranges can be stored in a file. The service reads the file on startup. There is also possibility to fetch the list from a remote server by providing the config file with the connection details.

Prerequisites

• kubectl
• kubernetes cluster with Kyma istio module installed

Installation

Enable ip-auth in the istio module by adding the following configuration to the istio CR:

spec:
  config:
    authorizers:
    - name: ip-auth
      port: 8000
      service: ip-auth.ip-auth.svc.cluster.local
      headers:
        inCheck:
          include:
          - x-envoy-external-address
          - x-forwarded-for      

You can edit the istio CR by running the following command:

kubectl edit istio -n kyma-system default

If you run your cluster on Google Cloud Platform or Microsoft Azure, you need to enable externalTrafficPolicy: Local in the istio-ingressgateway service. You can do this by running the following command:

kubectl patch svc istio-ingressgateway -n istio-system -p '{"spec":{"externalTrafficPolicy":"Local"}}'

Now create ip-auth namespace where the service with the configuration will be deployed.

kubectl create namespace ip-auth

The content of the config file should look like this:

clientId: here-goes-your-client-id
clientSecret: here-goes-your-client-secret
tokenUrl: https://example.com/oauth2/token
policyUrl: https://example.com/policy
usePolicyFile: true
usePolicyUrl: false
policyUpdateInterval: 600

To create a config secret run the following command:

kubectl -n ip-auth create secret generic config --from-file=config.yaml=sample-config.yaml

If you want to use a static list of blocked IP ranges, you can create the config file with the list of blocked IP ranges and create the config map from it. The content of the policy.json file should look like this:

[
  {
    "network": "1.2.3.0/24",
    "policy": "BLOCK_ACCESS"
  },
  {
    "network": "2.4.0.0/16",
    "policy": "BLOCK_ACCESS"
  },
  {
    "network": "5.6.7.128/25",
    "policy": "BLOCK_ACCESS"
  }
]

You can create the config map from the file by running the following command:

kubectl -n ip-auth create configmap policy --from-file=policy.json

To install ip-auth apply ip-auth.yaml manifest in your cluster:

kubectl apply -f https://raw.githubusercontent.com/kyma-project/ip-auth/main/ip-auth.yaml

It also creates AuthorizationPolicy that enables custom authorizer for all requests coming to istio ingress gateway.

Testing with your own IP

Deploy sample workload to test the service. You can use the following command:

kubectl apply -f https://raw.githubusercontent.com/kyma-project/ip-auth/main/workload.yaml

The sample workload URL can be fetched from this command:

export WORKLOAD_URL=$(kubectl get virtualservice -l apirule.gateway.kyma-project.io/v1beta1=httpbin.workload -n workload -ojsonpath='{.items[0].spec.hosts[0]}')

Now you can test the service:

curl -i "https://$WORKLOAD_URL/headers"

You should get a 200 OK response with the headers like this::

{
  "headers": {
    "Accept": "*/*", 
    "Host": "httpbin.xxxxx.kyma.ondemand.com", 
    "User-Agent": "curl/8.4.0", 
    "X-Envoy-Attempt-Count": "1", 
    "X-Envoy-External-Address": "121.122.123.124", 
    "X-Forwarded-Host": "httpbin.xxxx.kyma.ondemand.com"
  }
}

Now take the IP address from the X-Envoy-External-Address header and add it to the policy.json file. And recreate the config map with the new policy:

kubectl -n ip-auth create configmap policy --from-file=policy.json --dry-run=client -o yaml | kubectl apply -f -

Now restart the ip-auth service:

kubectl rollout restart deployment -n ip-auth ip-auth

Now when you run the curl command again, you should get a 403 Forbidden response.

Local development and testing

You can start ip-auth locally by running the following command:

go run main.go

Without config file, the service will use policy.json file from current directory. You can test the service by sending a request with the x-envoy-external-address header set to the IP address you want to check. For example:

curl -v -H "x-envoy-external-address: 1.2.3.0" 

If the IP address is in the list of blocked IP ranges, the service will return a 403 Forbidden response. If the IP address is not in the list, the service will return a 200 OK response.

Links

More information about istio module in Kyma can be found here.

Contributing

See the Contributing Rules.

Code of Conduct

See the Code of Conduct document.

Licensing

See the license file.