Return authentication webhook error message

staging/src/k8s.io/apiserver/plugin/pkg/authenticator/token/webhook/webhook.go

@@ -19,6 +19,7 @@ package webhook
 
 import (
 	"context"
+	"errors"
 	"time"
 
 	authentication "k8s.io/api/authentication/v1beta1"
@@ -120,7 +121,11 @@ func (w *WebhookTokenAuthenticator) AuthenticateToken(ctx context.Context, token
 
 	r.Status = result.Status
 	if !r.Status.Authenticated {
-		return nil, false, nil
+		var err error
+		if len(r.Status.Error) != 0 {
+			err = errors.New(r.Status.Error)
+		}
+		return nil, false, err
 	}
 
 	var extra map[string][]string