Security Problems

12 minute read

End-user authentication fails

With Istio, you can enable authentication for end users. Currently, the end user credential supported by the Istio authentication policy is JWT. The following is a guide for troubleshooting the end user JWT authentication.

Check your Istio authentication policy, principalBinding should be set as USE_ORIGIN to authenticate the end user.

If jwksUri isn’t set, make sure the JWT issuer is of url format and url + /.well-known/openid-configuration can be opened in browser; for example, if the JWT issuer is https://accounts.google.com, make sure https://accounts.google.com/.well-known/openid-configuration is a valid url and can be opened in a browser.

apiVersion: "authentication.istio.io/v1alpha1"
kind: "Policy"
metadata:
  name: "example-3"
spec:
  targets:
  - name: httpbin
  peers:
  - mtls:
  origins:
  - jwt:
      issuer: "628645741881-noabiu23f5a8m8ovd8ucv698lj78vv0l@developer.gserviceaccount.com"
      jwksUri: "https://www.googleapis.com/service_accounts/v1/jwk/628645741881-noabiu23f5a8m8ovd8ucv698lj78vv0l@developer.gserviceaccount.com"
  principalBinding: USE_ORIGIN

If the JWT token is placed in the Authorization header in http requests, make sure the JWT token is valid (not expired, etc). The fields in a JWT token can be decoded by using online JWT parsing tools, e.g., jwt.io.

Get the Istio proxy (i.e., Envoy) logs to verify the configuration which Pilot distributes is correct.

For example, if the authentication policy is enforced on the httpbin service in the namespace foo, use the command below to get logs from the Istio proxy, make sure local_jwks is set and the http response code is in the Istio proxy logs.

$ kubectl logs httpbin-68fbcdcfc7-hrnzm -c istio-proxy -n foo
[2018-07-04 19:13:30.762][15][info][config] ./src/envoy/http/jwt_auth/auth_store.h:72] Loaded JwtAuthConfig: rules {
  issuer: "628645741881-noabiu23f5a8m8ovd8ucv698lj78vv0l@developer.gserviceaccount.com"
  local_jwks {
    inline_string: "{\n \"keys\": [\n  {\n   \"kty\": \"RSA\",\n   \"alg\": \"RS256\",\n   \"use\": \"sig\",\n   \"kid\": \"03bc39a6b56602c0d2ad421c3993d5e4f88e6f54\",\n   \"n\": \"u9gnSMDYw4ggVKInAfxpXqItv9Ii7PlUFrAcwANQMW9fbZrFpITFD45t0gUy9CK4QewkLhqDDUJSvpH7wprS8Hi0M8wAJf_lgugdRr6Nc2qK-eywjjDK-afQjhGLcMJGS0YXi3K2lyP-oWiLingMbYRiJxTi86icWT8AU8bKoTyTPFOExAJkDFnquulU0_KlteZxbjnRIVvMKfpgZ3yK9Pzv7XjtdvO7xlr59K9Zotd4mgphIUADfw1fR0lNkjHQp9N0WP9cbOsyUwm5jjDklnyVh7yBHcEk1YHccntosxnwIn-cj538PSaL_qDZgDAsJKHPZlkiP_1mjsu3NkofIQ\",\n   \"e\": \"AQAB\"\n  },\n  {\n   \"kty\": \"RSA\",\n   \"alg\": \"RS256\",\n   \"use\": \"sig\",\n   \"kid\": \"60aef5b0877e9f0d67b787b5be797636735efdee\",\n   \"n\": \"0TmzDEN12GF9UaWJI40oKwJlu53ZQihHcaVi1thLGs1l3ubdPWv8MEsc9X2DjCRxEB6Ss1R2VOImrQ2RWFuBSNHorjE0_GyEGNzvOH-0uUQ5uES2HvEN7384XfUYj9MoTPibstDEl84pm4d3Ka3R_1wk03Jrl9MIq6fnV_4Z-F7O7ElGqk8xcsiVUowd447dwlrd55ChIyISF5PvbCLtOKz9FgTz2mEb8jmzuZQs5yICgKZCzlJ7xNOOmZcqCZf9Qzaz4OnVLXykBLzSuLMtxvvOxf53rvWB0F2__CjKlEWBCQkB39Zaa_4I8dCAVxgkeQhgoU26BdzLL28xjWzdbw\",\n   \"e\": \"AQAB\"\n  },\n  {\n   \"kty\": \"RSA\",\n   \"alg\": \"RS256\",\n   \"use\": \"sig\",\n   \"kid\": \"62a93512c9ee4c7f8067b5a216dade2763d32a47\",\n   \"n\": \"0YWnm_eplO9BFtXszMRQNL5UtZ8HJdTH2jK7vjs4XdLkPW7YBkkm_2xNgcaVpkW0VT2l4mU3KftR-6s3Oa5Rnz5BrWEUkCTVVolR7VYksfqIB2I_x5yZHdOiomMTcm3DheUUCgbJRv5OKRnNqszA4xHn3tA3Ry8VO3X7BgKZYAUh9fyZTFLlkeAh0-bLK5zvqCmKW5QgDIXSxUTJxPjZCgfx1vmAfGqaJb-nvmrORXQ6L284c73DUL7mnt6wj3H6tVqPKA27j56N0TB1Hfx4ja6Slr8S4EB3F1luYhATa1PKUSH8mYDW11HolzZmTQpRoLV8ZoHbHEaTfqX_aYahIw\",\n   \"e\": \"AQAB\"\n  },\n  {\n   \"kty\": \"RSA\",\n   \"alg\": \"RS256\",\n   \"use\": \"sig\",\n   \"kid\": \"b3319a147514df7ee5e4bcdee51350cc890cc89e\",\n   \"n\": \"qDi7Tx4DhNvPQsl1ofxxc2ePQFcs-L0mXYo6TGS64CY_2WmOtvYlcLNZjhuddZVV2X88m0MfwaSA16wE-RiKM9hqo5EY8BPXj57CMiYAyiHuQPp1yayjMgoE1P2jvp4eqF-BTillGJt5W5RuXti9uqfMtCQdagB8EC3MNRuU_KdeLgBy3lS3oo4LOYd-74kRBVZbk2wnmmb7IhP9OoLc1-7-9qU1uhpDxmE6JwBau0mDSwMnYDS4G_ML17dC-ZDtLd1i24STUw39KH0pcSdfFbL2NtEZdNeam1DDdk0iUtJSPZliUHJBI_pj8M-2Mn_oA8jBuI8YKwBqYkZCN1I95Q\",\n   \"e\": \"AQAB\"\n  }\n ]\n}\n"
  }
  forward: true
  forward_payload_header: "istio-sec-8a85f33ec44c5ccbaf951742ff0aaa34eb94d9bd"
}
allow_missing_or_failed: true
[2018-07-04 19:13:30.763][15][info][upstream] external/envoy/source/server/lds_api.cc:62] lds: add/update listener '10.8.2.9_8000'
[2018-07-04T19:13:39.755Z] "GET /ip HTTP/1.1" 401 - 0 29 0 - "-" "curl/7.35.0" "e8374005-1957-99e4-96b6-9d6ec5bef396" "httpbin.foo:8000" "-"
[2018-07-04T19:13:40.463Z] "GET /ip HTTP/1.1" 401 - 0 29 0 - "-" "curl/7.35.0" "9badd659-fa0e-9ca9-b4c0-9ac225571929" "httpbin.foo:8000" "-"

Authorization is too restrictive

When you first enable authorization for a service, all requests are denied by default. After you add one or more authorization policies, then matching requests should flow through. If all requests continue to be denied, you can try the following:

Make sure there is no typo in your policy YAML file.
Avoid enabling authorization for Istio Control Planes Components, including Mixer, Pilot, Ingress. Istio authorization policy is designed for authorizing access to services in Istio Mesh. Enabling it for Istio Control Planes Components may cause unexpected behavior.
Make sure that your ServiceRoleBinding and referred ServiceRole objects are in the same namespace (by checking “metadata”/”namespace” line).
Make sure that your service role and service role binding policies don’t use any HTTP only fields for TCP services. Otherwise, Istio ignores the policies as if they didn’t exist.
In Kubernetes environment, make sure all services in a ServiceRole object are in the same namespace as the ServiceRole itself. For example, if a service in a ServiceRole object is a.default.svc.cluster.local, the ServiceRole must be in the default namespace (metadata/namespace line should be default). For non-Kubernetes environments, all ServiceRoles and ServiceRoleBindings for a mesh should be in the same namespace.
Visit Ensure Authorization is Enabled Correctly to find out the exact cause.

Authorization is too permissive

If authorization checks are enabled for a service and yet requests to the service aren’t being blocked, then authorization was likely not enabled successfully. To verify, follow these steps:

Check the authorization concept documentation to correctly apply Istio authorization.
Avoid enabling authorization for Istio Control Planes Components, including Mixer, Pilot and Ingress. The Istio authorization features are designed for authorizing access to services in an Istio Mesh. Enabling the authorization features for the Istio Control Planes components can cause unexpected behavior.
In your Kubernetes environment, check deployments in all namespaces to make sure there is no legacy deployment left that can cause an error in Pilot. You can disable Pilot’s authorization plug-in if there is an error pushing authorization policy to Envoy.
Visit Ensure Authorization is Enabled Correctly to find out the exact cause.

Ensure authorization is enabled correctly

The ClusterRbacConfig default cluster level singleton custom resource controls the authorization functionality globally.

Run the following command to list existing ClusterRbacConfig:

$ kubectl get clusterrbacconfigs.rbac.istio.io --all-namespaces

Verify there is only one instance of ClusterRbacConfig with name default. Otherwise, Istio disables the authorization functionality and ignores all policies.
```
NAMESPACE   NAME      AGE
default     default   1d
```
If there is more than one ClusterRbacConfig instance, remove any additional ClusterRbacConfig instances and ensure only one instance is named default.

Ensure Pilot accepts the policies

Pilot converts and distributes your authorization policies to the proxies. The following steps help you ensure Pilot is working as expected:

Run the following command to export the Pilot ControlZ:

$ kubectl port-forward $(kubectl -n istio-system get pods -l istio=pilot -o jsonpath='{.items[0].metadata.name}') -n istio-system 9876:9876

Verify you see the following output:
```
Forwarding from 127.0.0.1:9876 -> 9876
```
Start your browser and open the ControlZ page at http://127.0.0.1:9876/scopez/.
Change the rbac Output Level to debug.
Use Ctrl+C in the terminal you started in step 1 to stop the port-forward command.
Print the log of Pilot and search for rbac with the following command:
You probably need to first delete and then re-apply your authorization policies so that the debug output is generated for these policies.
```
$ kubectl logs $(kubectl -n istio-system get pods -l istio=pilot -o jsonpath='{.items[0].metadata.name}') -c discovery -n istio-system | grep rbac
```
Check the output and verify:
- There are no errors.
- There is a "built filter config for ..." message which means the filter is generated for the target service.

For example, you might see something similar to the following:

2018-07-26T22:25:41.009838Z debug rbac building filter config for {sleep.foo.svc.cluster.local map[app:sleep pod-template-hash:3326367878] map[destination.name:sleep destination.namespace:foo destination.user:default]}
2018-07-26T22:25:41.009915Z info  rbac no service role in namespace foo
2018-07-26T22:25:41.009957Z info  rbac no service role binding in namespace foo
2018-07-26T22:25:41.010000Z debug rbac generated filter config: { }
2018-07-26T22:25:41.010114Z info  rbac built filter config for sleep.foo.svc.cluster.local
2018-07-26T22:25:41.182400Z debug rbac building filter config for {productpage.default.svc.cluster.local map[pod-template-hash:2600844901 version:v1 app:productpage] map[destination.name:productpage destination.namespace:default destination.user:bookinfo-productpage]}
2018-07-26T22:25:41.183131Z debug rbac checking role app2-grpc-viewer
2018-07-26T22:25:41.183214Z debug rbac role skipped for no AccessRule matched
2018-07-26T22:25:41.183255Z debug rbac checking role productpage-viewer
2018-07-26T22:25:41.183281Z debug rbac matched AccessRule[0]
2018-07-26T22:25:41.183390Z debug rbac generated filter config: {policies:<key:"productpage-viewer" value:<permissions:<and_rules:<rules:<or_rules:<rules:<header:<name:":method" exact_match:"GET" > > > > > > principals:<and_ids:<ids:<any:true > > > > >  }
2018-07-26T22:25:41.184407Z info  rbac built filter config for productpage.default.svc.cluster.local

It means Pilot generated:

An empty config for sleep.foo.svc.cluster.local as there is no authorization policies matched and Istio denies all requests sent to this service by default.
An config for productpage.default.svc.cluster.local and Istio will allow anyone to access it with GET method.

Ensure Pilot distributes policies to proxies correctly

Pilot distributes the authorization policies to proxies. The following steps help you ensure Pilot is working as expected:

Run the following command to get the proxy configuration dump for the productpage service:

$ kubectl exec  $(kubectl get pods -l app=productpage -o jsonpath='{.items[0].metadata.name}') -c istio-proxy -- pilot-agent request GET config_dump

Check the log and verify:
- The log includes an envoy.filters.http.rbac filter to enforce the authorization policy on each incoming request.
- Istio updates the filter accordingly after you update your authorization policy.

The following output means the proxy of productpage has enabled the envoy.filters.http.rbac filter with rules that allows anyone to access it via GET method. The shadow_rules are not used and you can ignored them safely.

{
 "name": "envoy.filters.http.rbac",
 "config": {
  "rules": {
   "policies": {
    "productpage-viewer": {
     "permissions": [
      {
       "and_rules": {
        "rules": [
         {
          "or_rules": {
           "rules": [
            {
             "header": {
              "exact_match": "GET",
              "name": ":method"
             }
            }
           ]
          }
         }
        ]
       }
      }
     ],
     "principals": [
      {
       "and_ids": {
        "ids": [
         {
          "any": true
         }
        ]
       }
      }
     ]
    }
   }
  },
  "shadow_rules": {
   "policies": {}
  }
 }
},

Ensure proxies enforce policies correctly

Proxies eventually enforce the authorization policies. The following steps help you ensure the proxy is working as expected:

Turn on the authorization debug logging in proxy with the following command:

$ kubectl exec $(kubectl get pods -l app=productpage -o jsonpath='{.items[0].metadata.name}') -c istio-proxy -- pilot-agent request POST 'logging?rbac=debug'

Verify you see the following output:

active loggers:
  ... ...
  rbac: debug
  ... ...

Visit the productpage in your browser to generate some logs.

Print the proxy logs with the following command:

$ kubectl logs $(kubectl get pods -l app=productpage -o jsonpath='{.items[0].metadata.name}') -c istio-proxy

Check the output and verify:
- The output log shows either enforced allowed or enforced denied depending on whether the request was allowed or denied respectively.
- Your authorization policy expects the data extracted from the request.

The following output means there is a GET request at path /productpage and the policy allows the request. The shadow denied has no effect and you can ignore it safely.

...
[2018-07-26 20:39:18.060][152][debug][rbac] external/envoy/source/extensions/filters/http/rbac/rbac_filter.cc:79] checking request: remoteAddress: 10.60.0.139:51158, localAddress: 10.60.0.93:9080, ssl: uriSanPeerCertificate: spiffe://cluster.local/ns/istio-system/sa/istio-ingressgateway-service-account, subjectPeerCertificate: O=, headers: ':authority', '35.238.0.62'
':path', '/productpage'
':method', 'GET'
'upgrade-insecure-requests', '1'
'user-agent', 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36'
'dnt', '1'
'accept', 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8'
'accept-encoding', 'gzip, deflate'
'accept-language', 'en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7'
'x-forwarded-for', '10.60.0.1'
'x-forwarded-proto', 'http'
'x-request-id', 'e23ea62d-b25d-91be-857c-80a058d746d4'
'x-b3-traceid', '5983108bf6d05603'
'x-b3-spanid', '5983108bf6d05603'
'x-b3-sampled', '1'
'x-istio-attributes', 'CikKGGRlc3RpbmF0aW9uLnNlcnZpY2UubmFtZRINEgtwcm9kdWN0cGFnZQoqCh1kZXN0aW5hdGlvbi5zZXJ2aWNlLm5hbWVzcGFjZRIJEgdkZWZhdWx0Ck8KCnNvdXJjZS51aWQSQRI/a3ViZXJuZXRlczovL2lzdGlvLWluZ3Jlc3NnYXRld2F5LTc2NjY0Y2NmY2Ytd3hjcjQuaXN0aW8tc3lzdGVtCj4KE2Rlc3RpbmF0aW9uLnNlcnZpY2USJxIlcHJvZHVjdHBhZ2UuZGVmYXVsdC5zdmMuY2x1c3Rlci5sb2NhbApDChhkZXN0aW5hdGlvbi5zZXJ2aWNlLmhvc3QSJxIlcHJvZHVjdHBhZ2UuZGVmYXVsdC5zdmMuY2x1c3Rlci5sb2NhbApBChdkZXN0aW5hdGlvbi5zZXJ2aWNlLnVpZBImEiRpc3RpbzovL2RlZmF1bHQvc2VydmljZXMvcHJvZHVjdHBhZ2U='
'content-length', '0'
'x-envoy-internal', 'true'
'sec-istio-authn-payload', 'CkVjbHVzdGVyLmxvY2FsL25zL2lzdGlvLXN5c3RlbS9zYS9pc3Rpby1pbmdyZXNzZ2F0ZXdheS1zZXJ2aWNlLWFjY291bnQSRWNsdXN0ZXIubG9jYWwvbnMvaXN0aW8tc3lzdGVtL3NhL2lzdGlvLWluZ3Jlc3NnYXRld2F5LXNlcnZpY2UtYWNjb3VudA=='
, dynamicMetadata: filter_metadata {
  key: "istio_authn"
  value {
    fields {
      key: "request.auth.principal"
      value {
        string_value: "cluster.local/ns/istio-system/sa/istio-ingressgateway-service-account"
      }
    }
    fields {
      key: "source.principal"
      value {
        string_value: "cluster.local/ns/istio-system/sa/istio-ingressgateway-service-account"
      }
    }
  }
}

[2018-07-26 20:39:18.060][152][debug][rbac] external/envoy/source/extensions/filters/http/rbac/rbac_filter.cc:88] shadow denied
[2018-07-26 20:39:18.060][152][debug][rbac] external/envoy/source/extensions/filters/http/rbac/rbac_filter.cc:98] enforced allowed
...

Keys and certificates errors

If you suspect that some of the keys and/or certificates used by Istio aren’t correct, the first step is to ensure that Citadel is healthy.

You can then verify that Citadel is actually generating keys and certificates:

$ kubectl get secret istio.my-sa -n my-ns
NAME                    TYPE                           DATA      AGE
istio.my-sa             istio.io/key-and-cert          3         24d

Where my-ns and my-sa are the namespace and service account your pod is running as.

If you want to check the keys and certificates of other service accounts, you can run the following command to list all secrets for which Citadel has generated a key and certificate:

$ kubectl get secret --all-namespaces | grep istio.io/key-and-cert
NAMESPACE      NAME                                                 TYPE                                  DATA      AGE
.....
istio-system   istio.istio-citadel-service-account                  istio.io/key-and-cert                 3         14d
istio-system   istio.istio-cleanup-old-ca-service-account           istio.io/key-and-cert                 3         14d
istio-system   istio.istio-egressgateway-service-account            istio.io/key-and-cert                 3         14d
istio-system   istio.istio-ingressgateway-service-account           istio.io/key-and-cert                 3         14d
istio-system   istio.istio-mixer-post-install-account               istio.io/key-and-cert                 3         14d
istio-system   istio.istio-mixer-service-account                    istio.io/key-and-cert                 3         14d
istio-system   istio.istio-pilot-service-account                    istio.io/key-and-cert                 3         14d
istio-system   istio.istio-sidecar-injector-service-account         istio.io/key-and-cert                 3         14d
istio-system   istio.prometheus                                     istio.io/key-and-cert                 3         14d
kube-public    istio.default                                        istio.io/key-and-cert                 3         14d
.....

Then check that the certificate is valid with:

$ kubectl get secret -o json istio.my-sa -n my-ns | jq -r '.data["cert-chain.pem"]' | base64 --decode | openssl x509 -noout -text
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            99:59:6b:a2:5a:f4:20:f4:03:d7:f0:bc:59:f5:d8:40
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: O = k8s.cluster.local
        Validity
            Not Before: Jun  4 20:38:20 2018 GMT
            Not After : Sep  2 20:38:20 2018 GMT
        Subject: O =
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:c8:a0:08:24:61:af:c1:cb:81:21:90:cc:03:76:
                    01:25:bc:ff:ca:25:fc:81:d1:fa:b8:04:aa:d4:6b:
                    55:e9:48:f2:e4:ab:22:78:03:47:26:bb:8f:22:10:
                    66:47:47:c3:b2:9a:70:f1:12:f1:b3:de:d0:e9:2d:
                    28:52:21:4b:04:33:fa:3d:92:8c:ab:7f:cc:74:c9:
                    c4:68:86:b0:4f:03:1b:06:33:48:e3:5b:8f:01:48:
                    6a:be:64:0e:01:f5:98:6f:57:e4:e7:b7:47:20:55:
                    98:35:f9:99:54:cf:a9:58:1e:1b:5a:0a:63:ce:cd:
                    ed:d3:a4:88:2b:00:ee:b0:af:e8:09:f8:a8:36:b8:
                    55:32:80:21:8e:b5:19:c0:2f:e8:ca:4b:65:35:37:
                    2f:f1:9e:6f:09:d4:e0:b1:3d:aa:5f:fe:25:1a:7b:
                    d4:dd:fe:d1:d3:b6:3c:78:1d:3b:12:c2:66:bd:95:
                    a8:3b:64:19:c0:51:05:9f:74:3d:6e:86:1e:20:f5:
                    ed:3a:ab:44:8d:7c:5b:11:14:83:ee:6b:a1:12:2e:
                    2a:0e:6b:be:02:ad:11:6a:ec:23:fe:55:d9:54:f3:
                    5c:20:bc:ec:bf:a6:99:9b:7a:2e:71:10:92:51:a7:
                    cb:79:af:b4:12:4e:26:03:ab:35:e2:5b:00:45:54:
                    fe:91
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Key Usage: critical
                Digital Signature, Key Encipherment
            X509v3 Extended Key Usage:
                TLS Web Server Authentication, TLS Web Client Authentication
            X509v3 Basic Constraints: critical
                CA:FALSE
            X509v3 Subject Alternative Name:
                URI:spiffe://cluster.local/ns/my-ns/sa/my-sa
    Signature Algorithm: sha256WithRSAEncryption
         78:77:7f:83:cc:fc:f4:30:12:57:78:62:e9:e2:48:d6:ea:76:
         69:99:02:e9:62:d2:53:db:2c:13:fe:0f:00:56:2b:83:ca:d3:
         4c:d2:01:f6:08:af:01:f2:e2:3e:bb:af:a3:bf:95:97:aa:de:
         1e:e6:51:8c:21:ee:52:f0:d3:af:9c:fd:f7:f9:59:16:da:40:
         4d:53:db:47:bb:9c:25:1a:6e:34:41:42:d9:26:f7:3a:a6:90:
         2d:82:42:97:08:f4:6b:16:84:d1:ad:e3:82:2c:ce:1c:d6:cd:
         68:e6:b0:5e:b5:63:55:3e:f1:ff:e1:a0:42:cd:88:25:56:f7:
         a8:88:a1:ec:53:f9:c1:2a:bb:5c:d7:f8:cb:0e:d9:f4:af:2e:
         eb:85:60:89:b3:d0:32:60:b4:a8:a1:ee:f3:3a:61:60:11:da:
         2d:7f:2d:35:ce:6e:d4:eb:5c:82:cf:5c:9a:02:c0:31:33:35:
         51:2b:91:79:8a:92:50:d9:e0:58:0a:78:9d:59:f4:d3:39:21:
         bb:b4:41:f9:f7:ec:ad:dd:76:be:28:58:c0:1f:e8:26:5a:9e:
         7b:7f:14:a9:18:8d:61:d1:06:e3:9e:0f:05:9e:1b:66:0c:66:
         d1:27:13:6d:ab:59:46:00:77:6e:25:f6:e8:41:ef:49:58:73:
         b4:93:04:46

Make sure the displayed certificate contains valid information. In particular, the Subject Alternative Name field should be URI:spiffe://cluster.local/ns/my-ns/sa/my-sa. If this is not the case, it is likely that something is wrong with your Citadel. Try to redeploy Citadel and check again.

Finally, you can verify that the key and certificate are correctly mounted by your sidecar proxy at the directory /etc/certs. You can use this command to check:

$ kubectl exec -it my-pod-id -c istio-proxy -- ls /etc/certs
cert-chain.pem    key.pem    root-cert.pem

Optionally, you could use the following command to check its contents:

$ kubectl exec -it my-pod-id -c istio-proxy -- cat /etc/certs/cert-chain.pem | openssl x509 -text -noout
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            7e:b4:44:fe:d0:46:ba:27:47:5a:50:c8:f0:8e:8b:da
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: O = k8s.cluster.local
        Validity
            Not Before: Jul 13 01:23:13 2018 GMT
            Not After : Oct 11 01:23:13 2018 GMT
        Subject: O =
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:bb:c9:cd:f4:b8:b5:e4:3b:f2:35:aa:4c:67:cc:
                    1b:a9:30:c4:b7:fd:0a:f5:ac:94:05:b5:82:96:b2:
                    c8:98:85:f9:fc:09:b3:28:34:5e:79:7e:a9:3c:58:
                    0a:14:43:c1:f4:d7:b8:76:ab:4e:1c:89:26:e8:55:
                    cd:13:6b:45:e9:f1:67:e1:9b:69:46:b4:7e:8c:aa:
                    fd:70:de:21:15:4f:f5:f3:0f:b7:d4:c6:b5:9d:56:
                    ef:8a:91:d7:16:fa:db:6e:4c:24:71:1c:9c:f3:d9:
                    4b:83:f1:dd:98:5b:63:5c:98:5e:2f:15:29:0f:78:
                    31:04:bc:1d:c8:78:c3:53:4f:26:b2:61:86:53:39:
                    0a:3b:72:3e:3d:0d:22:61:d6:16:72:5d:64:e3:78:
                    c8:23:9d:73:17:07:5a:6b:79:75:91:ce:71:4b:77:
                    c5:1f:60:f1:da:ca:aa:85:56:5c:13:90:23:02:20:
                    12:66:3f:8f:58:b8:aa:72:9d:36:f1:f3:b7:2b:2d:
                    3e:bb:7c:f9:b5:44:b9:57:cf:fc:2f:4b:3c:e6:ee:
                    51:ba:23:be:09:7b:e2:02:6a:6e:e7:83:06:cd:6c:
                    be:7a:90:f1:1f:2c:6d:12:9e:2f:0f:e4:8c:5f:31:
                    b1:a2:fa:0b:71:fa:e1:6a:4a:0f:52:16:b4:11:73:
                    65:d9
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Key Usage: critical
                Digital Signature, Key Encipherment
            X509v3 Extended Key Usage:
                TLS Web Server Authentication, TLS Web Client Authentication
            X509v3 Basic Constraints: critical
                CA:FALSE
            X509v3 Subject Alternative Name:
                URI:spiffe://cluster.local/ns/default/sa/bookinfo-productpage
    Signature Algorithm: sha256WithRSAEncryption
         8f:be:af:a4:ee:f7:be:21:e9:c8:c9:e2:3b:d3:ac:41:18:5d:
         f8:9a:85:0f:98:f3:35:af:b7:e1:2d:58:5a:e0:50:70:98:cc:
         75:f6:2e:55:25:ed:66:e7:a4:b9:4a:aa:23:3b:a6:ee:86:63:
         9f:d8:f9:97:73:07:10:25:59:cc:d9:01:09:12:f9:ab:9e:54:
         24:8a:29:38:74:3a:98:40:87:67:e4:96:d0:e6:c7:2d:59:3d:
         d3:ea:dd:6e:40:5f:63:bf:30:60:c1:85:16:83:66:66:0b:6a:
         f5:ab:60:7e:f5:3b:44:c6:11:5b:a1:99:0c:bd:53:b3:a7:cc:
         e2:4b:bd:10:eb:fb:f0:b0:e5:42:a4:b2:ab:0c:27:c8:c1:4c:
         5b:b5:1b:93:25:9a:09:45:7c:28:31:13:a3:57:1c:63:86:5a:
         55:ed:14:29:db:81:e3:34:47:14:ba:52:d6:3c:3d:3b:51:50:
         89:a9:db:17:e4:c4:57:ec:f8:22:98:b7:e7:aa:8a:72:28:9a:
         a7:27:75:60:85:20:17:1d:30:df:78:40:74:ea:bc:ce:7b:e5:
         a5:57:32:da:6d:f2:64:fb:28:94:7d:28:37:6f:3c:97:0e:9c:
         0c:33:42:f0:b6:f5:1c:0d:fb:70:65:aa:93:3e:ca:0e:58:ec:
         8e:d5:d0:1e

Mutual TLS errors

If you suspect problems with mutual TLS, first ensure that Citadel is healthy, and second ensure that keys and certificates are being delivered to sidecars properly.

If everything appears to be working so far, the next step is to verify that the right authentication policy is applied and the right destination rules are in place.

Citadel is not behaving properly

Citadel is not a critical data plane component. The default workload certificate lifetime is 3 months. Certificates will be rotated by Citadel before they expire. If Citadel is disabled for short maintenance periods, existing mutual TLS traffic will not be affected.

If you suspect Citadel isn’t working properly, verify the status of the istio-citadel pod:

$ kubectl get pod -l istio=citadel -n istio-system
NAME                                     READY     STATUS   RESTARTS   AGE
istio-citadel-ff5696f6f-ht4gq            1/1       Running  0          25d

If the istio-citadel pod doesn’t exist, try to re-deploy the pod.

If the istio-citadel pod is present but its status is not Running, run the commands below to get more debugging information and check if there are any errors:

$ kubectl logs -l istio=citadel -n istio-system
$ kubectl describe pod -l istio=citadel -n istio-system

If you want to check a workload (with default service account and default namespace) certificate’s lifetime:

$ kubectl get secret -o json istio.default -n default | jq -r '.data["cert-chain.pem"]' | base64 --decode | openssl x509 -noout -text | grep "Not After" -C 1
  Not Before: Jun  1 18:23:30 2019 GMT
  Not After : Aug 30 18:23:30 2019 GMT
Subject: