502 Bad Gateway Error After Instituting AuthorizationPolicy from Istio Documentation - authorization

Question

i'm using Istio 1.5.4 and trying apply the example referenced here:
https://istio.io/latest/docs/tasks/security/authentication/authn-policy/#end-user-authentication
Everything works as expected until defining the AuthorizationPolicy - the moment i introduce that i would get a 502 Bad Gateway error regardless if i provide a valid JWT token or not.
On a secondary note, I'm able to get the AuthorizationPolicy to work properly if i update the example to be applied at my own service namespaced level. Then RequestAuthentication + AuthorizationPolicy would work as expected, however, i would run into a different roadblock where now internal service would also require a valid jwt token.
authentication/authorization internal service issue

Answer 1

I've discovered that the 502 is a result of my loadbalancer health check failing due to the AuthorizationPolicy applied. Adding a conditional header User-Agent against my healh check probe seems to do the trick, but then i get back the net effect where no token provided is still getting through
No token is getting through because that´s how you configured your AuthorizationPolicy, that´s how source: requestPrincipals: ["*"] works. Take a look at this example.
RequestAuthentication defines what request authentication methods are supported by a workload. If will reject a request if the request contains invalid authentication information, based on the configured authentication rules. A request that does not contain any authentication credentials will be accepted but will not have any authenticated identity. To restrict access to authenticated requests only, this should be accompanied by an authorization rule. Examples:
Require JWT for all request for workloads that have label app:httpbin
apiVersion: security.istio.io/v1beta1
kind: RequestAuthentication
metadata:
name: httpbin
namespace: foo
spec:
selector:
matchLabels:
app: httpbin
jwtRules:
- issuer: "issuer-foo"
jwksUri: https://example.com/.well-known/jwks.json
---
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: httpbin
namespace: foo
spec:
selector:
matchLabels:
app: httpbin
rules:
- from:
- source:
requestPrincipals: ["*"]
Use requestPrincipals: ["testing#secure.istio.io/testing#secure.istio.io"] instead as mentioned here, then it will accept only requests with token.
apiVersion: security.istio.io/v1beta1
kind: RequestAuthentication
metadata:
name: frontend
namespace: default
spec:
selector:
matchLabels:
app: frontend
jwtRules:
- issuer: "testing#secure.istio.io"
jwksUri: "https://raw.githubusercontent.com/istio/istio/release-1.5/security/tools/jwt/samples/jwks.json"
The second resource is an AuthorizationPolicy, which ensures that all requests have a JWT - and rejects requests that do not, returning a 403 error.
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: require-jwt
namespace: default
spec:
selector:
matchLabels:
app: frontend
action: ALLOW
rules:
- from:
- source:
requestPrincipals: ["testing#secure.istio.io/testing#secure.istio.io"]
Once we apply these resources, we can curl the Istio ingress gateway without a JWT, and see that the AuthorizationPolicy is rejecting our request because we did not supply a token:
$ curl ${INGRESS_IP}
RBAC: access denied
Finally, if we curl with a valid JWT, we can successfully reach the frontend via the IngressGateway:
$ curl --header "Authorization: Bearer ${VALID_JWT}" ${INGRESS_IP}
Hello World! /