Authorization with JWT

Authorization with JWT

This task shows you how to set up an Istio authorization policy to enforce access based on a JSON Web Token (JWT). An Istio authorization policy supports both string typed and list-of-string typed JWT claims.

Before you begin

Before you begin this task, perform the following actions:

Read Authorization and Authentication.
Install Istio using Istio installation guide.
Deploy two workloads: httpbin and sleep. Deploy these in one namespace, for example foo. Both workloads run with an Envoy proxy in front of each. Deploy the example namespace and workloads using these commands:

Zip Zip
```
$ 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/sleep/sleep.yaml@) -n foo
```

Verify that sleep successfully communicates with httpbin using this command:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl http://httpbin.foo:8000/ip -s -o /dev/null -w "%{http_code}\n"
200

If you don’t see the expected output, retry after a few seconds. Caching and propagation can cause a delay.

Allow requests with valid JWT and list-typed claims

The following command creates the jwt-example request authentication policy for the httpbin workload in the foo namespace. This policy for httpbin workload accepts a JWT issued by testing@secure.istio.io:

$ kubectl apply -f - <<EOF
apiVersion: "security.istio.io/v1beta1"
kind: "RequestAuthentication"
metadata:
  name: "jwt-example"
  namespace: foo
spec:
  selector:
    matchLabels:
      app: httpbin
  jwtRules:
  - issuer: "testing@secure.istio.io"
    jwksUri: "https://raw.githubusercontent.com/istio/istio/release-1.8/security/tools/jwt/samples/jwks.json"
EOF

Verify that a request with an invalid JWT is denied:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl "http://httpbin.foo:8000/headers" -s -o /dev/null -H "Authorization: Bearer invalidToken" -w "%{http_code}\n"
401

Verify that a request without a JWT is allowed because there is no authorization policy:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl "http://httpbin.foo:8000/headers" -s -o /dev/null -w "%{http_code}\n"
200

The following command creates the require-jwt authorization policy for the httpbin workload in the foo namespace. The policy requires all requests to the httpbin workload to have a valid JWT with requestPrincipal set to testing@secure.istio.io/testing@secure.istio.io. Istio constructs the requestPrincipal by combining the iss and sub of the JWT token with a / separator as shown:
```
$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: require-jwt
  namespace: foo
spec:
  selector:
    matchLabels:
      app: httpbin
  action: ALLOW
  rules:
  - from:
    - source:
       requestPrincipals: ["testing@secure.istio.io/testing@secure.istio.io"]
EOF
```

Get the JWT that sets the iss and sub keys to the same value, testing@secure.istio.io. This causes Istio to generate the attribute requestPrincipal with the value testing@secure.istio.io/testing@secure.istio.io:

$ 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 -
{"exp":4685989700,"foo":"bar","iat":1532389700,"iss":"testing@secure.istio.io","sub":"testing@secure.istio.io"}

Verify that a request with a valid JWT is allowed:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl "http://httpbin.foo:8000/headers" -s -o /dev/null -H "Authorization: Bearer $TOKEN" -w "%{http_code}\n"
200

Verify that a request without a JWT is denied:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl "http://httpbin.foo:8000/headers" -s -o /dev/null -w "%{http_code}\n"
403

The following command updates the require-jwt authorization policy to also require the JWT to have a claim named groups containing the value group1:

$ kubectl apply -f - <<EOF
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
  name: require-jwt
  namespace: foo
spec:
  selector:
    matchLabels:
      app: httpbin
  action: ALLOW
  rules:
  - from:
    - source:
       requestPrincipals: ["testing@secure.istio.io/testing@secure.istio.io"]
    when:
    - key: request.auth.claims[groups]
      values: ["group1"]
EOF

Don’t include quotes in the request.auth.claims field unless the claim itself has quotes in it.

Get the JWT that sets the groups claim to a list of strings: group1 and group2:

$ TOKEN_GROUP=$(curl https://raw.githubusercontent.com/istio/istio/release-1.8/security/tools/jwt/samples/groups-scope.jwt -s) && echo "$TOKEN_GROUP" | cut -d '.' -f2 - | base64 --decode -
{"exp":3537391104,"groups":["group1","group2"],"iat":1537391104,"iss":"testing@secure.istio.io","scope":["scope1","scope2"],"sub":"testing@secure.istio.io"}

Verify that a request with the JWT that includes group1 in the groups claim is allowed:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl "http://httpbin.foo:8000/headers" -s -o /dev/null -H "Authorization: Bearer $TOKEN_GROUP" -w "%{http_code}\n"
200

Verify that a request with a JWT, which doesn’t have the groups claim is rejected:

$ kubectl exec "$(kubectl get pod -l app=sleep -n foo -o jsonpath={.items..metadata.name})" -c sleep -n foo -- curl "http://httpbin.foo:8000/headers" -s -o /dev/null -H "Authorization: Bearer $TOKEN" -w "%{http_code}\n"
403

Clean up

Remove the namespace foo:
```
$ kubectl delete namespace foo
```

Authorization with JWT

Authorization with JWT

Before you begin

Allow requests with valid JWT and list-typed claims

Clean up

See also