Support PeerAuthentication (STRICT) mode

[YonkaFang]

Bug Description

I'm following the tutorial https://istio.io/latest/docs/tasks/security/authentication/authn-policy/#globally-enabling-istio-mutual-tls-in-strict-mod.

I find that I can access the pod without sidecar from ambent pod or sidecar pod when I've set the mtls mode to STRICT globally or in namespace level or per-pod.

From the envoy config_dump of caller side, I see the actual behaviour is PERMISSIVE mode no matter what I set.

      "cluster_name": "outbound|8000||httpbin.default-sidecar.svc.cluster.local",
      "endpoints": [
       {
        "locality": {},
        "lb_endpoints": [
         {
          "endpoint": {
           "address": {
            "envoy_internal_address": {
             "server_listener_name": "tunnel",
             "endpoint_id": "10.244.1.31:80"  // pod with sidecar
            }
           },
           "health_check_config": {}
          },
          "health_status": "HEALTHY",
          "metadata": {
           "filter_metadata": {
            "tunnel": {
             "destination": "10.244.1.31:80",
             "address": "10.244.1.31:15008"
            },
            "envoy.transport_socket_match": {
             "tunnel": "h2"
            },
            "istio": {
             "workload": "httpbinv1;default-sidecar;httpbin;v1;Kubernetes"
            }
           }
          },
          "load_balancing_weight": 1
         },
         {
          "endpoint": {
           "address": {
            "socket_address": {
             "address": "10.244.2.18",  // pod without sidecar
             "port_value": 80
            }
           },
           "health_check_config": {}
          },
          "health_status": "HEALTHY",
          "metadata": {
           "filter_metadata": {
            "istio": {
             "workload": "httpbinv2;default-sidecar;httpbin;v2;Kubernetes"
            }
           }
          },
          "load_balancing_weight": 1
         }
        ],
        "load_balancing_weight": 2
       }
      ],
      "policy": {
       "overprovisioning_factor": 140
      }
     }
    },    

Version

./bin/istioctl version
client version: 0.0.0-ambient.191fe680b52c1754ee72a06b3e0d3f9d116f2e82
control plane version: 0.0.0
data plane version: 0.0.0-ambient.191fe680b52c1754ee72a06b3e0d3f9d116f2e82 (11 proxies)

Client Version: v1.25.2
Kustomize Version: v4.5.7
Server Version: v1.25.2

Additional Information

No response

[howardjohn]

This is working as implemented; there is currently open discussion if we will support this API in ambient

[fzh890523]

This is working as implemented; there is currently open discussion if we will support this API in ambient

Can I see similar discussions somewhere, I'm more concerned about the completeness of ambient's capabilities

[howardjohn]

Doc is in https://docs.google.com/document/d/1Lk1I1qB-XwVWFP0sVcIN5JMJZHjuF3j8lGWtUeDK6pY/edit#heading=h.nluvz4y67j4c. Note its very much under discussion.

I can assure anyone reading this though, some equivalent to "only allow mTLS" will be available. That is 100% critical

[linsun]

not stale, we still need discussion on if peer authentication should be supported and if so when.

[keithmattix]

Update: After discussion in the Ambient WG, we decided to move forward with supporting PeerAuthentication for now. I'll take care of the ambient implementation