Basic external auth policy

Authenticate requests with a basic dictionary of usernames and passwords.

Basic authentication sends encoded user credentials in a standard header within the request. Then, Gloo Mesh authenticates the request against a dictionary of usernames and passwords that are written in the external auth policy. If the credentials in the request header match the policy, the request is sent to the destination. If not, Gloo Mesh Gateway returns a 401 response.

You might use basic auth for testing environments, such as when you release a new API method or version to a small number of known users.

If you import or export resources across workspaces, your policies might not apply. For more information, see Import and export policies.

Before you begin

This guide assumes that you use the same names for components like clusters, workspaces, and namespaces as in the getting started. If you have different names, make sure to update the sample configuration files in this guide.

Complete the multicluster getting started guide to set up the following testing environment.
- Three clusters along with environment variables for the clusters and their Kubernetes contexts.
- The Gloo meshctl CLI, along with other CLI tools such as kubectl and istioctl.
- The Gloo management server in the management cluster, and the Gloo agents in the workload clusters.
- Istio installed in the workload clusters.
- A simple Gloo workspace setup.
Install Bookinfo and other sample apps.
Make sure that the external auth service is installed and running. If not, install the external auth service.
```
kubectl get pods --context $REMOTE_CONTEXT1 -A -l app=ext-auth-service
```
Make sure that you have the following CLI tools, or something comparable:
- htpasswd to generate hashed, salted passwords.
- base64 to encode strings.

Apply a basic external auth policy

You can apply a basic external auth policy at the route or destination level. For more information, see Applying policies.

This policy currently does not support selecting VirtualDestinations as a destination.

When you apply this custom resource to your cluster, Gloo Mesh (Gloo Platform APIs) automatically checks the configuration against validation rules and value constraints. You can also run a pre-admission validation check by using the meshctl x validate resources command. For more information, see the resource validation overview and the CLI command reference.

Step 1: Configure a basic external auth policy

Generate a salt and hashed password for your user credentials. The following example uses the htpasswd tool for a user named user.
```
htpasswd -nbm user password
```
Example output:
```
user:$apr1$TYiryv0/$8BvzLUO9IfGPGGsPnAgSu1
```
Retrieve the salt and hashed password from the output of the previous step.
- Salt: TYiryv0/
- Hashed password: 8BvzLUO9IfGPGGsPnAgSu1
Review the following sample configuration file.

apiVersion: security.policy.gloo.solo.io/v2
kind: ExtAuthPolicy
metadata:
  name: basic-auth
  namespace: bookinfo
spec:
  applyToDestinations:
  - port:
      number: 9080
    selector:
      labels:
        app: ratings
  config:
    glooAuth:
      configs:
      - basicAuth:
          apr:
            users:
              user:
                hashedPassword: 8BvzLUO9IfGPGGsPnAgSu1
                salt: TYiryv0/
    server:
      name: default-server

Review the following table to understand this configuration. For more information, see the API docs.

Setting	Description
`applyToDestinations`	Use labels to apply the policy to destinations. Destinations might be a Kubernetes service, VirtualDestination, or ExternalService (if supported by the policy). If you do not specify any destinations or routes, the policy applies to all destinations in the workspace by default. If you do not specify any destinations but you do specify a route, the policy applies to the route but to no destinations.
`basicAuth`	Configure the basic auth credentials to use to authenticate requests. The example sets up user credentials for a user named `user` in the required APR1 format. For more information, see the API reference.
`hashedPassword`	The hashed password that you generated in the previous step. The example sets `8BvzLUO9IfGPGGsPnAgSu1`.
`salt`	The salt, or random data that hashes the password, that you generated in the previous step. The example sets `TYiryv0/`.
`server`	The `ExtAuthServer` resource that represents the server for the policy to use. In this example, only the `name` is specified. Gloo attempts to find the resource in the same namespace and cluster as the policy, or you can add `namespace` and `cluster` fields. To create an `ExtAuthServer` resource, see Set up the Gloo Mesh (Gloo Platform APIs) external auth server.

Step 2: Verify basic external auth policies

Apply the example basic external auth policy and server in the workload cluster. The following example refers directly to the default Gloo Mesh (Gloo Platform APIs) external auth service, but you can also use a virtual destination instead. For more information, see External auth server setup. Note: Change cluster-1 as needed to your cluster’s actual name.

kubectl apply --context ${REMOTE_CONTEXT1} -f - << EOF
apiVersion: security.policy.gloo.solo.io/v2
kind: ExtAuthPolicy
metadata:
  name: basic-auth
  namespace: bookinfo
spec:
  applyToDestinations:
  - port:
      number: 9080
    selector:
      labels:
        app: ratings
  config:
    glooAuth:
      configs:
      - basicAuth:
          apr:
            users:
              user:
                hashedPassword: 8BvzLUO9IfGPGGsPnAgSu1
                salt: TYiryv0/
    server:
      name: default-server
---
apiVersion: admin.gloo.solo.io/v2
kind: ExtAuthServer
metadata:
  name: default-server
  namespace: bookinfo
spec:
  destinationServer:
    port:
      number: 8083
    ref:
      cluster: cluster-1
      name: ext-auth-service
      namespace: gloo-mesh
EOF

Apply external auth to external services

The following example is for an external auth policy that applies to an external service. Note that this policy requires different routing table and external auth server resources, as well as an external service.

apiVersion: security.policy.gloo.solo.io/v2
kind: ExtAuthPolicy
metadata:
  name: httpbin-basic-auth
  namespace: bookinfo
spec:
  applyToRoutes:
  - route:
      labels:
        route: external-service
  config:
    glooAuth:
      configs:
      - basicAuth:
          apr:
            users:
              user:
                hashedPassword: 8BvzLUO9IfGPGGsPnAgSu1
                salt: TYiryv0/
    server:
      name: default-server

apiVersion: admin.gloo.solo.io/v2
kind: ExtAuthServer
metadata:
  name: default-server
  namespace: bookinfo
spec:
  destinationServer:
    port:
      number: 8083
    ref:
      cluster: cluster-1
      name: ext-auth-service
      namespace: gloo-mesh

apiVersion: networking.gloo.solo.io/v2
kind: ExternalService
metadata:
  name: external-service
  namespace: bookinfo
spec:
  hosts:
  - httpbin.solo
  ports:
  - name: http
    number: 8080
    protocol: HTTP

apiVersion: networking.gloo.solo.io/v2
kind: RouteTable
metadata:
  name: external-service-northsouth
  namespace: bookinfo
spec:
  defaultDestination:
    kind: EXTERNAL_SERVICE
    port:
      number: 8080
    ref:
      name: external-service
      namespace: bookinfo
  hosts:
  - www.example.com
  http:
  - forwardTo: {}
    labels:
      "no": auth
    matchers:
    - headers:
      - name: noauth
        value: "true"
    name: external-service-no-auth
  - forwardTo: {}
    labels:
      route: external-service
    name: external-service-northsouth
  virtualGateways:
  - name: istio-ingressgateway

kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete ExtAuthPolicy basic-auth kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete ExtAuthServer default-server kubectl --context $REMOTE_CONTEXT1 -n bookinfo delete VirtualDestination reviews-global