Denials and White/Black Listing

This task shows how to control access to a service using simple denials or white/black listing.

Before you begin

• Set up Istio on Kubernetes by following the instructions in the Installation guide.

• Deploy the Bookinfo sample application.

• Initialize the application version routing to direct reviews service requests from test user “jason” to version v2 and requests from any other user to v3.

  $ kubectl apply -f @samples/bookinfo/networking/virtual-service-all-v1.yaml@

  and then run the following command:

  $ kubectl apply -f @samples/bookinfo/networking/virtual-service-reviews-jason-v2-v3.yaml@

  If you are using a namespace other than default, use kubectl -n namespace ... to specify the namespace.

Simple denials

Using Istio you can control access to a service based on any attributes that are available within Mixer. This simple form of access control is based on conditionally denying requests using Mixer selectors.

Consider the Bookinfo sample application where the ratings service is accessed by multiple versions of the reviews service. We would like to cut off access to version v3 of the reviews service.

1. Point your browser at the Bookinfo productpage (http://$GATEWAY_URL/productpage).

   If you log in as user “jason”, you should see black rating stars with each review, indicating that the ratings service is being called by the “v2” version of the reviews service.

   If you log in as any other user (or logout) you should see red rating stars with each review, indicating that the ratings service is being called by the “v3” version of the reviews service.

2. Explicitly deny access to version v3 of the reviews service.

   Run the following command to set up the deny rule along with a handler and an instance.

   $ kubectl apply -f @samples/bookinfo/policy/mixer-rule-deny-label.yaml@
   Created config denier/default/denyreviewsv3handler at revision 2882105
   Created config checknothing/default/denyreviewsv3request at revision 2882106
   Created config rule/default/denyreviewsv3 at revision 2882107

   Notice the following in the denyreviewsv3 rule:

   match: destination.labels["app"] == "ratings" && source.labels["app"]=="reviews" && source.labels["version"] == "v3"

   It matches requests coming from the service reviews with label v3 to the service ratings.

   This rule uses the denier adapter to deny requests coming from version v3 of the reviews service. The adapter always denies requests with a preconfigured status code and message. The status code and the message is specified in the denier adapter configuration.

3. Refresh the productpage in your browser.

   If you are logged out or logged in as any user other than “jason” you will no longer see red ratings stars because the reviews:v3 service has been denied access to the ratings service. In contrast, if you log in as user “jason” (the reviews:v2 user) you continue to see the black ratings stars.

whitelists or blacklists

Istio also supports attribute-based whitelists and blacklists. The following whitelist configuration is equivalent to the denier configuration in the previous section. The rule effectively rejects requests from version v3 of the reviews service.

1. Remove the denier configuration that you added in the previous section.

   $ kubectl delete -f @samples/bookinfo/policy/mixer-rule-deny-label.yaml@

2. Verify that when you access the Bookinfo productpage (http://$GATEWAY_URL/productpage) without logging in, you see red stars. After performing the following steps you will no longer be able to see stars unless you are logged in as “jason”.

3. Create configuration for the list adapter that lists versions v1, v2. Save the following YAML snippet as whitelist-handler.yaml:

   apiVersion: config.istio.io/v1alpha2
   kind: listchecker
   metadata:
     name: whitelist
   spec:
     # providerUrl: ordinarily black and white lists are maintained
     # externally and fetched asynchronously using the providerUrl.
     overrides: ["v1", "v2"]  # overrides provide a static list
     blacklist: false

   and then run the following command:

   $ kubectl apply -f whitelist-handler.yaml

4. Extract the version label by creating an instance of the listentry template. Save the following YAML snippet as appversion-instance.yaml:

   apiVersion: config.istio.io/v1alpha2
   kind: listentry
   metadata:
     name: appversion
   spec:
     value: source.labels["version"]

   and then run the following command:

   $ kubectl apply -f appversion-instance.yaml

5. Enable whitelist checking for the ratings service. Save the following YAML snippet as checkversion-rule.yaml:

   apiVersion: config.istio.io/v1alpha2
   kind: rule
   metadata:
     name: checkversion
   spec:
     match: destination.labels["app"] == "ratings"
     actions:
     - handler: whitelist.listchecker
       instances:
       - appversion.listentry

   and then run the following command:

   $ kubectl apply -f checkversion-rule.yaml

6. Verify that when you access the Bookinfo productpage (http://$GATEWAY_URL/productpage) without logging in, you see no stars. Verify that after logging in as “jason” you see black stars.

Cleanup

• Remove the mixer configuration:

  $ kubectl delete -f checkversion-rule.yaml
  $ kubectl delete -f appversion-instance.yaml
  $ kubectl delete -f whitelist-handler.yaml

• Remove the application routing rules:

  $ kubectl delete -f @samples/bookinfo/networking/virtual-service-all-v1.yaml@

• Remove the application destination rules:

  $ kubectl delete -f @samples/bookinfo/networking/destination-rule-all.yaml@

  If you enabled mutual TLS, please run the following instead

  $ kubectl delete -f @samples/bookinfo/networking/destination-rule-all-mtls.yaml@

• If you are not planning to explore any follow-on tasks, refer to the Bookinfo cleanup instructions to shutdown the application.

See also