Merge pull request #64140 from dixudx/add_e2e_kubelet_port

Automatic merge from submit-queue (batch tested with PRs 64140, 64898, 65022, 65037, 65027). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Add e2e regression tests for the kubelet being secure

**What this PR does / why we need it**:
This PR does,

1. The kubelet cAdvisor port (4194) can't be reached, neither via the API server proxy nor directly on the public IP address
2. The kubelet read-only port (10255) can't be reached, neither via the API server proxy nor directly on the public IP address
3. The kubelet can delegate ServiceAccount tokens to the API server
4. The kubelet's main port (10250) has both authentication (should fail with no credentials) and authorization (should fail with insufficient permissions) set-up

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes kubernetes/kubeadm#838

**Special notes for your reviewer**:
/cc luxas tallclair 
**Release note**:

```release-note
Add e2e regression tests for the kubelet being secure
```

test/e2e/auth/BUILD

@@ -12,12 +12,14 @@ go_library(
         "certificates.go",
         "framework.go",
         "metadata_concealment.go",
+        "node_authn.go",
         "node_authz.go",
         "pod_security_policy.go",
         "service_accounts.go",
     ],
     importpath = "k8s.io/kubernetes/test/e2e/auth",
     deps = [
+        "//pkg/master/ports:go_default_library",
         "//pkg/security/apparmor:go_default_library",
         "//pkg/security/podsecuritypolicy/seccomp:go_default_library",
         "//pkg/security/podsecuritypolicy/util:go_default_library",

test/e2e/auth/node_authn.go

@@ -0,0 +1,107 @@
+/*
+Copyright 2018 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"
+
+	"k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/kubernetes/pkg/master/ports"
+	"k8s.io/kubernetes/test/e2e/framework"
+	imageutils "k8s.io/kubernetes/test/utils/image"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = SIGDescribe("[Feature:NodeAuthenticator]", func() {
+
+	f := framework.NewDefaultFramework("node-authn")
+	var ns string
+	var nodeIPs []string
+	BeforeEach(func() {
+		ns = f.Namespace.Name
+
+		nodeList, err := f.ClientSet.CoreV1().Nodes().List(metav1.ListOptions{})
+		Expect(err).NotTo(HaveOccurred())
+		Expect(len(nodeList.Items)).NotTo(BeZero())
+
+		pickedNode := nodeList.Items[0]
+		nodeIPs = framework.GetNodeAddresses(&pickedNode, v1.NodeExternalIP)
+		// The pods running in the cluster can see the internal addresses.
+		nodeIPs = append(nodeIPs, framework.GetNodeAddresses(&pickedNode, v1.NodeInternalIP)...)
+
+		// make sure ServiceAccount admission controller is enabled, so secret generation on SA creation works
+		sa, err := f.ClientSet.CoreV1().ServiceAccounts(ns).Get("default", metav1.GetOptions{})
+		Expect(err).NotTo(HaveOccurred())
+		Expect(len(sa.Secrets)).NotTo(BeZero())
+	})
+
+	It("The kubelet's main port 10250 should reject requests with no credentials", func() {
+		pod := createNodeAuthTestPod(f)
+		for _, nodeIP := range nodeIPs {
+			// Anonymous authentication is disabled by default
+			result := framework.RunHostCmdOrDie(ns, pod.Name, fmt.Sprintf("curl -sIk -o /dev/null -w '%s' https://%s:%v/metrics", "%{http_code}", nodeIP, ports.KubeletPort))
+			Expect(result).To(Or(Equal("401"), Equal("403")), "the kubelet's main port 10250 should reject requests with no credentials")
+		}
+	})
+
+	It("The kubelet can delegate ServiceAccount tokens to the API server", func() {
+		By("create a new ServiceAccount for authentication")
+		trueValue := true
+		newSA := &v1.ServiceAccount{
+			ObjectMeta: metav1.ObjectMeta{
+				Namespace: ns,
+				Name:      "node-auth-newSA",
+			},
+			AutomountServiceAccountToken: &trueValue,
+		}
+		_, err := f.ClientSet.CoreV1().ServiceAccounts(ns).Create(newSA)
+		Expect(err).NotTo(HaveOccurred())
+
+		pod := createNodeAuthTestPod(f)
+
+		for _, nodeIP := range nodeIPs {
+			result := framework.RunHostCmdOrDie(ns,
+				pod.Name,
+				fmt.Sprintf("curl -sIk -o /dev/null -w '%s' --header \"Authorization: Bearer `%s`\" https://%s:%v/metrics",
+					"%{http_code}",
+					"cat /var/run/secrets/kubernetes.io/serviceaccount/token",
+					nodeIP, ports.KubeletPort))
+			Expect(result).To(Or(Equal("401"), Equal("403")), "the kubelet can delegate ServiceAccount tokens to the API server")
+		}
+	})
+})
+
+func createNodeAuthTestPod(f *framework.Framework) *v1.Pod {
+	pod := &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			GenerateName: "test-node-authn-",
+		},
+		Spec: v1.PodSpec{
+			Containers: []v1.Container{{
+				Name:    "test-node-authn",
+				Image:   imageutils.GetE2EImage(imageutils.Hostexec),
+				Command: []string{"sleep 3600"},
+			}},
+			RestartPolicy: v1.RestartPolicyNever,
+		},
+	}
+
+	return f.PodClient().CreateSync(pod)
+}

test/e2e/framework/kubelet_stats.go

@@ -492,7 +492,7 @@ type usageDataPerContainer struct {
 }
 
 func GetKubeletHeapStats(c clientset.Interface, nodeName string) (string, error) {
-	client, err := NodeProxyRequest(c, nodeName, "debug/pprof/heap")
+	client, err := NodeProxyRequest(c, nodeName, "debug/pprof/heap", ports.KubeletPort)
 	if err != nil {
 		return "", err
 	}

test/e2e/framework/util.go

@@ -4492,7 +4492,7 @@ func isElementOf(podUID types.UID, pods *v1.PodList) bool {
 const proxyTimeout = 2 * time.Minute
 
 // NodeProxyRequest performs a get on a node proxy endpoint given the nodename and rest client.
-func NodeProxyRequest(c clientset.Interface, node, endpoint string) (restclient.Result, error) {
+func NodeProxyRequest(c clientset.Interface, node, endpoint string, port int) (restclient.Result, error) {
 	// proxy tends to hang in some cases when Node is not ready. Add an artificial timeout for this call.
 	// This will leak a goroutine if proxy hangs. #22165
 	var result restclient.Result
@@ -4501,7 +4501,7 @@ func NodeProxyRequest(c clientset.Interface, node, endpoint string) (restclient.
 		result = c.CoreV1().RESTClient().Get().
 			Resource("nodes").
 			SubResource("proxy").
-			Name(fmt.Sprintf("%v:%v", node, ports.KubeletPort)).
+			Name(fmt.Sprintf("%v:%v", node, port)).
 			Suffix(endpoint).
 			Do()
 
@@ -4529,7 +4529,7 @@ func GetKubeletRunningPods(c clientset.Interface, node string) (*v1.PodList, err
 
 func getKubeletPods(c clientset.Interface, node, resource string) (*v1.PodList, error) {
 	result := &v1.PodList{}
-	client, err := NodeProxyRequest(c, node, resource)
+	client, err := NodeProxyRequest(c, node, resource, ports.KubeletPort)
 	if err != nil {
 		return &v1.PodList{}, err
 	}

test/e2e/lifecycle/BUILD

@@ -12,6 +12,7 @@ go_library(
         "cluster_upgrade.go",
         "framework.go",
         "ha_master.go",
+        "kubelet_security.go",
         "reboot.go",
         "resize_nodes.go",
         "restart.go",
@@ -20,6 +21,7 @@ go_library(
     deps = [
         "//pkg/apis/core:go_default_library",
         "//pkg/kubelet/pod:go_default_library",
+        "//pkg/master/ports:go_default_library",
         "//pkg/util/version:go_default_library",
         "//test/e2e/chaosmonkey:go_default_library",
         "//test/e2e/common:go_default_library",

test/e2e/lifecycle/kubelet_security.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2018 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 lifecycle
+
+import (
+	"fmt"
+	"net"
+	"net/http"
+	"time"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/kubernetes/pkg/master/ports"
+	"k8s.io/kubernetes/test/e2e/framework"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = SIGDescribe("Ports Security Check [Feature:KubeletSecurity]", func() {
+	f := framework.NewDefaultFramework("kubelet-security")
+
+	var node *v1.Node
+	var nodeName string
+
+	BeforeEach(func() {
+		nodes := framework.GetReadySchedulableNodesOrDie(f.ClientSet)
+		Expect(len(nodes.Items)).NotTo(BeZero())
+		node = &nodes.Items[0]
+		nodeName = node.Name
+	})
+
+	// make sure kubelet readonly (10255) and cadvisor (4194) ports are disabled via API server proxy
+	It(fmt.Sprintf("should not be able to proxy to the readonly kubelet port %v using proxy subresource", ports.KubeletReadOnlyPort), func() {
+		result, err := framework.NodeProxyRequest(f.ClientSet, nodeName, "pods/", ports.KubeletReadOnlyPort)
+		Expect(err).NotTo(HaveOccurred())
+
+		var statusCode int
+		result.StatusCode(&statusCode)
+		Expect(statusCode).NotTo(Equal(http.StatusOK))
+	})
+	It("should not be able to proxy to cadvisor port 4194 using proxy subresource", func() {
+		result, err := framework.NodeProxyRequest(f.ClientSet, nodeName, "containers/", 4194)
+		Expect(err).NotTo(HaveOccurred())
+
+		var statusCode int
+		result.StatusCode(&statusCode)
+		Expect(statusCode).NotTo(Equal(http.StatusOK))
+	})
+
+	// make sure kubelet readonly (10255) and cadvisor (4194) ports are closed on the public IP address
+	disabledPorts := []int{ports.KubeletReadOnlyPort, 4194}
+	for _, port := range disabledPorts {
+		It(fmt.Sprintf("should not have port %d open on its all public IP addresses", port), func() {
+			portClosedTest(f, node, port)
+		})
+	}
+})
+
+// checks whether the target port is closed
+func portClosedTest(f *framework.Framework, pickNode *v1.Node, port int) {
+	nodeAddrs := framework.GetNodeAddresses(pickNode, v1.NodeExternalIP)
+	Expect(len(nodeAddrs)).NotTo(BeZero())
+
+	for _, addr := range nodeAddrs {
+		conn, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", addr, port), 1*time.Minute)
+		if err == nil {
+			conn.Close()
+			framework.Failf("port %d is not disabled", port)
+		}
+	}
+}