Configuring JSON Web Token authentication for Knative services - Security | Serverless

Enabling sidecar injection for a Knative service
Using JSON Web Token authentication with Service Mesh 2.x and OpenShift Serverless
Using JSON Web Token authentication with Service Mesh 1.x and OpenShift Serverless

After the Service Mesh integration with OpenShift Serverless and Kourier has been configured on your cluster, you can enable JSON Web Token (JWT) authentication for your Knative services.

Enabling sidecar injection for a Knative service

You can add the sidecar.istio.io/inject="true" annotation to a Knative service to enable sidecar injection for that service.

Adding sidecar injection to pods in system namespaces, such as knative-serving and knative-serving-ingress, is not supported when Kourier is enabled.

Prerequisites

You have installed the OpenShift Serverless Operator and Knative Serving.
Install the OpenShift CLI (oc).
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in Red Hat OpenShift Service on AWS.

Procedure

Add the sidecar.istio.io/inject="true" annotation to your Service resource:

Example service

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: <service_name>
spec:
  template:
    metadata:
      annotations:
        sidecar.istio.io/inject: "true" (1)
        sidecar.istio.io/rewriteAppHTTPProbers: "true" (2)
...

1	Add the `sidecar.istio.io/inject="true"` annotation.
2	You must set the annotation `sidecar.istio.io/rewriteAppHTTPProbers: "true"` in your Knative service as OpenShift Serverless versions 1.14.0 and higher use an HTTP probe as the readiness probe for Knative services by default.

Apply your Service resource YAML file:
```
$ oc apply -f <filename>
```

Using JSON Web Token authentication with Service Mesh 2.x and OpenShift Serverless

You can use the following procedure to enable using JSON Web Token authentication with Service Mesh 2.x and OpenShift Serverless.

Prerequisites

You have installed the OpenShift Serverless Operator and Knative Serving.
Install the OpenShift CLI (oc).
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in Red Hat OpenShift Service on AWS.

Procedure

Create a RequestAuthentication resource in each serverless application namespace that is a member in the ServiceMeshMemberRoll object:

apiVersion: security.istio.io/v1beta1
kind: RequestAuthentication
metadata:
  name: jwt-example
  namespace: <namespace>
spec:
  jwtRules:
  - issuer: testing@secure.istio.io
    jwksUri: https://raw.githubusercontent.com/istio/istio/release-1.8/security/tools/jwt/samples/jwks.json

Apply the RequestAuthentication resource:
```
$ oc apply -f <filename>
```
Allow access to the RequestAuthenticaton resource from system pods for each serverless application namespace that is a member in the ServiceMeshMemberRoll object, by creating the following AuthorizationPolicy resource:
```
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: allowlist-by-paths
  namespace: <namespace>
spec:
  action: ALLOW
  rules:
  - to:
    - operation:
        paths:
        - /metrics (1)
        - /healthz (2)
```
1 The path on your application to collect metrics by system pod.

2 The path on your application to probe by system pod.
Apply the AuthorizationPolicy resource:
```
$ oc apply -f <filename>
```

For each serverless application namespace that is a member in the ServiceMeshMemberRoll object, create the following AuthorizationPolicy resource:

apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: require-jwt
  namespace: <namespace>
spec:
  action: ALLOW
  rules:
  - from:
    - source:
       requestPrincipals: ["testing@secure.istio.io/testing@secure.istio.io"]

Apply the AuthorizationPolicy resource:
```
$ oc apply -f <filename>
```

Verification

If you try to use a curl request to get the Knative service URL, it is denied:
Example command
```
$ curl http://hello-example-1-default.apps.mycluster.example.com/
```
Example output
```
RBAC: access denied
```

Verify the request with a valid JWT.

Get the valid JWT token:

$ TOKEN=$(curl https://raw.githubusercontent.com/istio/istio/release-1.8/security/tools/jwt/samples/demo.jwt -s) && echo "$TOKEN" | cut -d '.' -f2 - | base64 --decode -

Access the service by using the valid token in the curl request header:

$ curl -H "Authorization: Bearer $TOKEN"  http://hello-example-1-default.apps.example.com

The request is now allowed:

Example output

Hello OpenShift!

Using JSON Web Token authentication with Service Mesh 1.x and OpenShift Serverless

You can use the following procedure to enable using JSON Web Token authentication with Service Mesh 1.x and OpenShift Serverless.

Prerequisites

You have installed the OpenShift Serverless Operator and Knative Serving.
Install the OpenShift CLI (oc).
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in Red Hat OpenShift Service on AWS.

Procedure

Create a policy in a serverless application namespace which is a member in the ServiceMeshMemberRoll object, that only allows requests with valid JSON Web Tokens (JWT):

The paths /metrics and /healthz must be included in excludedPaths because they are accessed from system pods in the knative-serving namespace.

apiVersion: authentication.istio.io/v1alpha1
kind: Policy
metadata:
  name: default
  namespace: <namespace>
spec:
  origins:
  - jwt:
      issuer: testing@secure.istio.io
      jwksUri: "https://raw.githubusercontent.com/istio/istio/release-1.6/security/tools/jwt/samples/jwks.json"
      triggerRules:
      - excludedPaths:
        - prefix: /metrics (1)
        - prefix: /healthz (2)
  principalBinding: USE_ORIGIN

1	The path on your application to collect metrics by system pod.
2	The path on your application to probe by system pod.

Apply the Policy resource:
```
$ oc apply -f <filename>
```

Verification

If you try to use a curl request to get the Knative service URL, it is denied:

$ curl http://hello-example-default.apps.mycluster.example.com/

Example output

Origin authentication failed.

Verify the request with a valid JWT.

Get the valid JWT token:

$ TOKEN=$(curl https://raw.githubusercontent.com/istio/istio/release-1.6/security/tools/jwt/samples/demo.jwt -s) && echo "$TOKEN" | cut -d '.' -f2 - | base64 --decode -

Access the service by using the valid token in the curl request header:

$ curl http://hello-example-default.apps.mycluster.example.com/ -H "Authorization: Bearer $TOKEN"

The request is now allowed:

Example output

Hello OpenShift!