/*
Copyright 2017 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package auth

import (
	"fmt"
	"time"

	"k8s.io/api/core/v1"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/wait"
	clientset "k8s.io/client-go/kubernetes"
	restclient "k8s.io/client-go/rest"
	"k8s.io/kubernetes/test/e2e/framework"
	imageutils "k8s.io/kubernetes/test/utils/image"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
)

const (
	NodesGroup     = "system:nodes"
	NodeNamePrefix = "system:node:"
)

var _ = SIGDescribe("[Feature:NodeAuthorizer]", func() {

	f := framework.NewDefaultFramework("node-authz")
	// client that will impersonate a node
	var c clientset.Interface
	var ns string
	var asUser string
	var defaultSaSecret string
	var nodeName string
	BeforeEach(func() {
		ns = f.Namespace.Name

		nodeList, err := f.ClientSet.CoreV1().Nodes().List(metav1.ListOptions{})
		Expect(err).NotTo(HaveOccurred(), "failed to list nodes in namespace: %s", ns)
		Expect(len(nodeList.Items)).NotTo(Equal(0))
		nodeName = nodeList.Items[0].Name
		asUser = NodeNamePrefix + nodeName
		saName := "default"
		sa, err := f.ClientSet.CoreV1().ServiceAccounts(ns).Get(saName, metav1.GetOptions{})
		Expect(len(sa.Secrets)).NotTo(Equal(0))
		Expect(err).NotTo(HaveOccurred(), "failed to retrieve service account (%s:%s)", ns, saName)
		defaultSaSecret = sa.Secrets[0].Name
		By("Creating a kubernetes client that impersonates a node")
		config, err := framework.LoadConfig()
		Expect(err).NotTo(HaveOccurred(), "failed to load kubernetes client config")
		config.Impersonate = restclient.ImpersonationConfig{
			UserName: asUser,
			Groups:   []string{NodesGroup},
		}
		c, err = clientset.NewForConfig(config)
		Expect(err).NotTo(HaveOccurred(), "failed to create Clientset for the given config: %+v", *config)

	})
	It("Getting a non-existent secret should exit with the Forbidden error, not a NotFound error", func() {
		_, err := c.CoreV1().Secrets(ns).Get("foo", metav1.GetOptions{})
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))
	})

	It("Getting an existing secret should exit with the Forbidden error", func() {
		_, err := c.CoreV1().Secrets(ns).Get(defaultSaSecret, metav1.GetOptions{})
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))
	})

	It("Getting a non-existent configmap should exit with the Forbidden error, not a NotFound error", func() {
		_, err := c.CoreV1().ConfigMaps(ns).Get("foo", metav1.GetOptions{})
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))
	})

	It("Getting an existing configmap should exit with the Forbidden error", func() {
		By("Create a configmap for testing")
		configmap := &v1.ConfigMap{
			ObjectMeta: metav1.ObjectMeta{
				Namespace: ns,
				Name:      "node-auth-configmap",
			},
			Data: map[string]string{
				"data": "content",
			},
		}
		_, err := f.ClientSet.CoreV1().ConfigMaps(ns).Create(configmap)
		Expect(err).NotTo(HaveOccurred(), "failed to create configmap (%s:%s) %+v", ns, configmap.Name, *configmap)
		_, err = c.CoreV1().ConfigMaps(ns).Get(configmap.Name, metav1.GetOptions{})
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))
	})

	It("Getting a secret for a workload the node has access to should succeed", func() {
		By("Create a secret for testing")
		secret := &v1.Secret{
			ObjectMeta: metav1.ObjectMeta{
				Namespace: ns,
				Name:      "node-auth-secret",
			},
			Data: map[string][]byte{
				"data": []byte("keep it secret"),
			},
		}
		_, err := f.ClientSet.CoreV1().Secrets(ns).Create(secret)
		Expect(err).NotTo(HaveOccurred(), "failed to create secret (%s:%s)", ns, secret.Name)

		By("Node should not get the secret")
		_, err = c.CoreV1().Secrets(ns).Get(secret.Name, metav1.GetOptions{})
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))

		By("Create a pod that use the secret")
		pod := &v1.Pod{
			ObjectMeta: metav1.ObjectMeta{
				Name: "pause",
			},
			Spec: v1.PodSpec{
				Containers: []v1.Container{
					{
						Name:  "pause",
						Image: imageutils.GetPauseImageName(),
					},
				},
				NodeName: nodeName,
				Volumes: []v1.Volume{
					{
						Name: "node-auth-secret",
						VolumeSource: v1.VolumeSource{
							Secret: &v1.SecretVolumeSource{
								SecretName: secret.Name,
							},
						},
					},
				},
			},
		}

		_, err = f.ClientSet.CoreV1().Pods(ns).Create(pod)
		Expect(err).NotTo(HaveOccurred(), "failed to create pod (%s:%s)", ns, pod.Name)

		By("The node should able to access the secret")
		itv := framework.Poll
		dur := 1 * time.Minute
		err = wait.Poll(itv, dur, func() (bool, error) {
			_, err = c.CoreV1().Secrets(ns).Get(secret.Name, metav1.GetOptions{})
			if err != nil {
				framework.Logf("Failed to get secret %v, err: %v", secret.Name, err)
				return false, nil
			}
			return true, nil
		})
		Expect(err).NotTo(HaveOccurred(), "failed to get secret after trying every %v for %v (%s:%s)", itv, dur, ns, secret.Name)
	})

	It("A node shouldn't be able to create another node", func() {
		node := &v1.Node{
			ObjectMeta: metav1.ObjectMeta{Name: "foo"},
			TypeMeta: metav1.TypeMeta{
				Kind:       "Node",
				APIVersion: "v1",
			},
		}
		By(fmt.Sprintf("Create node foo by user: %v", asUser))
		_, err := c.CoreV1().Nodes().Create(node)
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))
	})

	It("A node shouldn't be able to delete another node", func() {
		By(fmt.Sprintf("Create node foo by user: %v", asUser))
		err := c.CoreV1().Nodes().Delete("foo", &metav1.DeleteOptions{})
		Expect(apierrors.IsForbidden(err)).Should(Equal(true))
	})
})