Merge pull request #20347 from ericchiang/authz_grpc

Auto commit by PR queue bot
2025-07-29 06:27:05 +00:00 · 2016-02-26 22:00:42 -08:00 · 2016-02-26 22:00:42 -08:00 · 00d99ac261
commit 00d99ac261
parent 1f9a7e2167 b50ede606f
13 changed files with 1198 additions and 34 deletions
--- a/cmd/kube-apiserver/app/options/options.go
+++ b/cmd/kube-apiserver/app/options/options.go
@ -47,7 +47,7 @@ type APIServer struct {
 	AdvertiseAddress           net.IP
 	AllowPrivileged            bool
 	AuthorizationMode          string
-	AuthorizationPolicyFile    string
+	AuthorizationConfig        apiserver.AuthorizationConfig
 	BasicAuthFile              string
 	CloudConfigFile            string
 	CloudProvider              string
@ -214,7 +214,8 @@ func (s *APIServer) AddFlags(fs *pflag.FlagSet) {
 	fs.BoolVar(&s.ServiceAccountLookup, "service-account-lookup", s.ServiceAccountLookup, "If true, validate ServiceAccount tokens exist in etcd as part of authentication.")
 	fs.StringVar(&s.KeystoneURL, "experimental-keystone-url", s.KeystoneURL, "If passed, activates the keystone authentication plugin")
 	fs.StringVar(&s.AuthorizationMode, "authorization-mode", s.AuthorizationMode, "Ordered list of plug-ins to do authorization on secure port. Comma-delimited list of: "+strings.Join(apiserver.AuthorizationModeChoices, ","))
-	fs.StringVar(&s.AuthorizationPolicyFile, "authorization-policy-file", s.AuthorizationPolicyFile, "File with authorization policy in csv format, used with --authorization-mode=ABAC, on the secure port.")
+	fs.StringVar(&s.AuthorizationConfig.PolicyFile, "authorization-policy-file", s.AuthorizationConfig.PolicyFile, "File with authorization policy in csv format, used with --authorization-mode=ABAC, on the secure port.")
+	fs.StringVar(&s.AuthorizationConfig.WebhookConfigFile, "authorization-webhook-config-file", s.AuthorizationConfig.WebhookConfigFile, "File with webhook configuration in kubeconfig format, used with --authorization-mode=Webhook. The API server will query the remote service to determine access on the API server's secure port.")
 	fs.StringVar(&s.AdmissionControl, "admission-control", s.AdmissionControl, "Ordered list of plug-ins to do admission control of resources into cluster. Comma-delimited list of: "+strings.Join(admission.GetPlugins(), ", "))
 	fs.StringVar(&s.AdmissionControlConfigFile, "admission-control-config-file", s.AdmissionControlConfigFile, "File with admission control configuration.")
 	fs.StringSliceVar(&s.EtcdServerList, "etcd-servers", s.EtcdServerList, "List of etcd servers to watch (http://ip:port), comma separated. Mutually exclusive with -etcd-config")
--- a/cmd/kube-apiserver/app/server.go
+++ b/cmd/kube-apiserver/app/server.go
@ -406,7 +406,7 @@ func Run(s *options.APIServer) error {
 	}

 	authorizationModeNames := strings.Split(s.AuthorizationMode, ",")
-	authorizer, err := apiserver.NewAuthorizerFromAuthorizationConfig(authorizationModeNames, s.AuthorizationPolicyFile)
+	authorizer, err := apiserver.NewAuthorizerFromAuthorizationConfig(authorizationModeNames, s.AuthorizationConfig)
 	if err != nil {
 		glog.Fatalf("Invalid Authorization Config: %v", err)
 	}
--- a/docs/admin/authorization.md
+++ b/docs/admin/authorization.md
@ -49,10 +49,12 @@ The following implementations are available, and are selected by flag:
  - `--authorization-mode=AlwaysDeny`
  - `--authorization-mode=AlwaysAllow`
  - `--authorization-mode=ABAC`
+  - `--authorization-mode=Webhook`

 `AlwaysDeny` blocks all requests (used in tests).
 `AlwaysAllow` allows all requests; use if you don't need authorization.
 `ABAC` allows for user-configured authorization policy.  ABAC stands for Attribute-Based Access Control.
+`Webhook` allows for authorization to be driven by a remote service using REST.

 ## ABAC Mode

@ -167,6 +169,111 @@ For example, if you wanted to grant the default service account in the kube-syst

 The apiserver will need to be restarted to pickup the new policy lines.

+## Webhook Mode
+
+When specified, mode `Webhook` causes Kubernetes to query an outside REST service when determining user privileges.
+
+### Configuration File Format
+
+Mode `Webhook` requires a file for HTTP configuration, specify by the `--authorization-webhook-config-file=SOME_FILENAME` flag.
+
+The configuration file uses the [kubeconfig](../user-guide/kubeconfig-file.md) file format. Within the file "users" refers to the API Server webhook and "clusters" refers to the remote service.
+
+A configuration example which uses HTTPS client auth:
+
+```yaml
+# clusters refers to the remote service.
+clusters:
+  - name: name-of-remote-authz-service
+    cluster:
+      certificate-authority: /path/to/ca.pem      # CA for verifying the remote service.
+      server: https://authz.example.com/authorize # URL of remote service to query. Must use 'https'.
+
+# users refers to the API Server's webhook configuration.
+users:
+  - name: name-of-api-server
+    user:
+      client-certificate: /path/to/cert.pem # cert for the webhook plugin to use
+      client-key: /path/to/key.pem          # key matching the cert
+```
+
+### Request Payloads
+
+When faced with an authorization decision, the API Server POSTs a JSON serialized api.authorization.v1beta1.SubjectAccessReview object describing the action. This object contains fields describing the user attempting to make the request, and either details about the resource being accessed or requests attributes.
+
+Note that webhook API objects are subject to the same [versioning compatibility rules](../api.md) as other Kubernetes API objects. Implementers should be aware of loser compatibility promises for beta objects and check the "apiVersion" field of the request to ensure correct deserialization. Additionally, the API Server must enable the `authorization.k8s.io/v1beta1` API extensions group (`--runtime-config=authorization.k8s.io/v1beta1=true`).
+
+An example request body:
+
+```json
+{
+  "apiVersion": "authorization.k8s.io/v1beta1",
+  "kind": "SubjectAccessReview",
+  "spec": {
+    "resourceAttributes": {
+      "namespace": "kittensandponies",
+      "verb": "GET",
+      "group": "*",
+      "resource": "pods"
+    },
+    "user": "jane",
+    "group": [
+      "group1",
+      "group2"
+    ]
+  }
+}
+```
+
+The remote service is expected to fill the SubjectAccessReviewStatus field of the request and respond to either allow or disallow access. The response body's "spec" field is ignored and may be omitted. A permissive response would return:
+
+```json
+{
+  "apiVersion": "authorization.k8s.io/v1beta1",
+  "kind": "SubjectAccessReview",
+  "status": {
+    "allowed": true
+  }
+}
+```
+
+To disallow access, the remote service would return:
+
+```json
+{
+  "apiVersion": "authorization.k8s.io/v1beta1",
+  "kind": "SubjectAccessReview",
+  "status": {
+    "allowed": false,
+    "reason": "user does not have read access to the namespace"
+  }
+}
+```
+
+Access to non-resource paths are sent as:
+
+```json
+{
+  "apiVersion": "authorization.k8s.io/v1beta1",
+  "kind": "SubjectAccessReview",
+  "spec": {
+    "nonResourceAttributes": {
+      "path": "/debug",
+      "verb": "GET"
+    },
+    "user": "jane",
+    "group": [
+      "group1",
+      "group2"
+    ]
+  }
+}
+```
+
+Non-resource paths include: `/api`, `/apis`, `/metrics`, `/resetMetrics`, `/logs`, `/debug`, `/healthz`, `/swagger-ui/`, `/swaggerapi/`, `/ui`, and `/version.` Clients require access to `/api`, `/api/*/`, `/apis/`, `/apis/*`, `/apis/*/*`, and `/version` to discover what resources and versions are present on the server. Access to other non-resource paths can be disallowed without restricting access to the REST api.
+
+For further documentation refer to the authorization.v1beta1 API objects and plugin/pkg/auth/authorizer/webhook/webhook.go.
+
 ## Plugin Development

 Other implementations can be developed fairly easily.
--- a/docs/admin/kube-apiserver.md
+++ b/docs/admin/kube-apiserver.md
@ -56,8 +56,9 @@ kube-apiserver
      --advertise-address=<nil>: The IP address on which to advertise the apiserver to members of the cluster. This address must be reachable by the rest of the cluster. If blank, the --bind-address will be used. If --bind-address is unspecified, the host's default interface will be used.
      --allow-privileged[=false]: If true, allow privileged containers.
      --apiserver-count=1: The number of apiservers running in the cluster
-      --authorization-mode="AlwaysAllow": Ordered list of plug-ins to do authorization on secure port. Comma-delimited list of: AlwaysAllow,AlwaysDeny,ABAC
+      --authorization-mode="AlwaysAllow": Ordered list of plug-ins to do authorization on secure port. Comma-delimited list of: AlwaysAllow,AlwaysDeny,ABAC,Webhook
      --authorization-policy-file="": File with authorization policy in csv format, used with --authorization-mode=ABAC, on the secure port.
+      --authorization-webhook-config-file="": File with webhook configuration in kubeconfig format, used with --authorization-mode=Webhook. The API server will query the remote service to determine access on the API server's secure port.
      --basic-auth-file="": If set, the file that will be used to admit requests to the secure port of the API server via http basic authentication.
      --bind-address=0.0.0.0: The IP address on which to listen for the --secure-port port. The associated interface(s) must be reachable by the rest of the cluster, and by CLI/web clients. If blank, all interfaces will be used (0.0.0.0).
      --cert-dir="/var/run/kubernetes": The directory where the TLS certs are located (by default /var/run/kubernetes). If --tls-cert-file and --tls-private-key-file are provided, this flag will be ignored.
--- a/hack/test-go.sh
+++ b/hack/test-go.sh
@ -326,7 +326,7 @@ for (( i=0, j=0; ; )); do
  # KUBE_TEST_API sets the version of each group to be tested. KUBE_API_VERSIONS
  # register the groups/versions as supported by k8s. So KUBE_API_VERSIONS
  # needs to be the superset of KUBE_TEST_API.
-  KUBE_TEST_API="${apiVersion}" KUBE_API_VERSIONS="v1,autoscaling/v1,batch/v1,extensions/v1beta1,componentconfig/v1alpha1,metrics/v1alpha1" ETCD_PREFIX=${etcdPrefix} runTests "$@"
+  KUBE_TEST_API="${apiVersion}" KUBE_API_VERSIONS="v1,autoscaling/v1,batch/v1,extensions/v1beta1,componentconfig/v1alpha1,metrics/v1alpha1,authorization.k8s.io/v1beta1" ETCD_PREFIX=${etcdPrefix} runTests "$@"
  i=${i}+1
  j=${j}+1
  if [[ i -eq ${apiVersionsCount} ]] && [[ j -eq ${etcdPrefixesCount} ]]; then
--- a/hack/verify-flags/known-flags.txt
+++ b/hack/verify-flags/known-flags.txt
@ -20,6 +20,7 @@ apiserver-count
 auth-path
 authorization-mode
 authorization-policy-file
+authorization-webhook-config-file
 basic-auth-file
 bench-pods
 bench-quiet
--- a/pkg/apiserver/authz.go
+++ b/pkg/apiserver/authz.go
@ -23,6 +23,7 @@ import (
 	"k8s.io/kubernetes/pkg/auth/authorizer"
 	"k8s.io/kubernetes/pkg/auth/authorizer/abac"
 	"k8s.io/kubernetes/pkg/auth/authorizer/union"
+	"k8s.io/kubernetes/plugin/pkg/auth/authorizer/webhook"
 )

 // Attributes implements authorizer.Attributes interface.
@ -60,15 +61,28 @@ const (
 	ModeAlwaysAllow string = "AlwaysAllow"
 	ModeAlwaysDeny  string = "AlwaysDeny"
 	ModeABAC        string = "ABAC"
+	ModeWebhook     string = "Webhook"
 )

 // Keep this list in sync with constant list above.
-var AuthorizationModeChoices = []string{ModeAlwaysAllow, ModeAlwaysDeny, ModeABAC}
+var AuthorizationModeChoices = []string{ModeAlwaysAllow, ModeAlwaysDeny, ModeABAC, ModeWebhook}
+
+type AuthorizationConfig struct {
+	// Options for ModeABAC
+
+	// Path to a ABAC policy file.
+	PolicyFile string
+
+	// Options for ModeWebhook
+
+	// Kubeconfig file for Webhook authorization plugin.
+	WebhookConfigFile string
+}

 // NewAuthorizerFromAuthorizationConfig returns the right sort of union of multiple authorizer.Authorizer objects
 // based on the authorizationMode or an error.  authorizationMode should be a comma separated values
 // of AuthorizationModeChoices.
-func NewAuthorizerFromAuthorizationConfig(authorizationModes []string, authorizationPolicyFile string) (authorizer.Authorizer, error) {
+func NewAuthorizerFromAuthorizationConfig(authorizationModes []string, config AuthorizationConfig) (authorizer.Authorizer, error) {

 	if len(authorizationModes) == 0 {
 		return nil, errors.New("Atleast one authorization mode should be passed")
@ -88,23 +102,35 @@ func NewAuthorizerFromAuthorizationConfig(authorizationModes []string, authoriza
 		case ModeAlwaysDeny:
 			authorizers = append(authorizers, NewAlwaysDenyAuthorizer())
 		case ModeABAC:
-			if authorizationPolicyFile == "" {
+			if config.PolicyFile == "" {
 				return nil, errors.New("ABAC's authorization policy file not passed")
 			}
-			abacAuthorizer, err := abac.NewFromFile(authorizationPolicyFile)
+			abacAuthorizer, err := abac.NewFromFile(config.PolicyFile)
 			if err != nil {
 				return nil, err
 			}
 			authorizers = append(authorizers, abacAuthorizer)
+		case ModeWebhook:
+			if config.WebhookConfigFile == "" {
+				return nil, errors.New("Webhook's configuration file not passed")
+			}
+			webhookAuthorizer, err := webhook.New(config.WebhookConfigFile)
+			if err != nil {
+				return nil, err
+			}
+			authorizers = append(authorizers, webhookAuthorizer)
 		default:
 			return nil, fmt.Errorf("Unknown authorization mode %s specified", authorizationMode)
 		}
 		authorizerMap[authorizationMode] = true
 	}

-	if !authorizerMap[ModeABAC] && authorizationPolicyFile != "" {
+	if !authorizerMap[ModeABAC] && config.PolicyFile != "" {
 		return nil, errors.New("Cannot specify --authorization-policy-file without mode ABAC")
 	}
+	if !authorizerMap[ModeWebhook] && config.WebhookConfigFile != "" {
+		return nil, errors.New("Cannot specify --authorization-webhook-config-file without mode Webhook")
+	}

 	return union.New(authorizers...), nil
 }
--- a/pkg/apiserver/authz_test.go
+++ b/pkg/apiserver/authz_test.go
@ -41,31 +41,75 @@ func TestNewAlwaysDenyAuthorizer(t *testing.T) {
 // NewAuthorizerFromAuthorizationConfig has multiple return possibilities. This test
 // validates that errors are returned only when proper.
 func TestNewAuthorizerFromAuthorizationConfig(t *testing.T) {
-	// Unknown modes should return errors
-	if _, err := NewAuthorizerFromAuthorizationConfig([]string{"DoesNotExist"}, ""); err == nil {
-		t.Errorf("NewAuthorizerFromAuthorizationConfig using a fake mode should have returned an error")
+
+	examplePolicyFile := "../auth/authorizer/abac/example_policy_file.jsonl"
+
+	tests := []struct {
+		modes   []string
+		config  AuthorizationConfig
+		wantErr bool
+		msg     string
+	}{
+		{
+			// Unknown modes should return errors
+			modes:   []string{"DoesNotExist"},
+			wantErr: true,
+			msg:     "using a fake mode should have returned an error",
+		},
+		{
+			// ModeAlwaysAllow and ModeAlwaysDeny should return without authorizationPolicyFile
+			// but error if one is given
+			modes: []string{ModeAlwaysAllow, ModeAlwaysDeny},
+			msg:   "returned an error for valid config",
+		},
+		{
+			// ModeABAC requires a policy file
+			modes:   []string{ModeAlwaysAllow, ModeAlwaysDeny, ModeABAC},
+			wantErr: true,
+			msg:     "specifying ABAC with no policy file should return an error",
+		},
+		{
+			// ModeABAC should not error if a valid policy path is provided
+			modes:  []string{ModeAlwaysAllow, ModeAlwaysDeny, ModeABAC},
+			config: AuthorizationConfig{PolicyFile: examplePolicyFile},
+			msg:    "errored while using a valid policy file",
+		},
+		{
+
+			// Authorization Policy file cannot be used without ModeABAC
+			modes:   []string{ModeAlwaysAllow, ModeAlwaysDeny},
+			config:  AuthorizationConfig{PolicyFile: examplePolicyFile},
+			wantErr: true,
+			msg:     "should have errored when Authorization Policy File is used without ModeABAC",
+		},
+		{
+			// Atleast one authorizationMode is necessary
+			modes:   []string{},
+			config:  AuthorizationConfig{PolicyFile: examplePolicyFile},
+			wantErr: true,
+			msg:     "should have errored when no authorization modes are passed",
+		},
+		{
+			// ModeWebhook requires at minimum a target.
+			modes:   []string{ModeWebhook},
+			wantErr: true,
+			msg:     "should have errored when config was empty with ModeWebhook",
+		},
+		{
+			// Cannot provide webhook flags without ModeWebhook
+			modes:   []string{ModeAlwaysAllow},
+			config:  AuthorizationConfig{WebhookConfigFile: "authz_webhook_config.yml"},
+			wantErr: true,
+			msg:     "should have errored when Webhook config file is used without ModeWebhook",
+		},
 	}

-	// ModeAlwaysAllow and ModeAlwaysDeny should return without authorizationPolicyFile
-	// but error if one is given
-	if _, err := NewAuthorizerFromAuthorizationConfig([]string{ModeAlwaysAllow, ModeAlwaysDeny}, ""); err != nil {
-		t.Errorf("NewAuthorizerFromAuthorizationConfig returned an error: %s", err)
-	}
-
-	// ModeABAC requires a policy file
-	if _, err := NewAuthorizerFromAuthorizationConfig([]string{ModeAlwaysAllow, ModeAlwaysDeny, ModeABAC}, ""); err == nil {
-		t.Errorf("NewAuthorizerFromAuthorizationConfig using a fake mode should have returned an error")
-	}
-	// ModeABAC should not error if a valid policy path is provided
-	if _, err := NewAuthorizerFromAuthorizationConfig([]string{ModeAlwaysAllow, ModeAlwaysDeny, ModeABAC}, "../auth/authorizer/abac/example_policy_file.jsonl"); err != nil {
-		t.Errorf("NewAuthorizerFromAuthorizationConfig errored while using a valid policy file: %s", err)
-	}
-	// Authorization Policy file cannot be used without ModeABAC
-	if _, err := NewAuthorizerFromAuthorizationConfig([]string{ModeAlwaysAllow, ModeAlwaysDeny}, "../auth/authorizer/abac/example_policy_file.jsonl"); err == nil {
-		t.Errorf("NewAuthorizerFromAuthorizationConfig should have errored when Authorization Policy File is used without ModeABAC")
-	}
-	// Atleast one authorizationMode is necessary
-	if _, err := NewAuthorizerFromAuthorizationConfig([]string{}, "../auth/authorizer/abac/example_policy_file.jsonl"); err == nil {
-		t.Errorf("NewAuthorizerFromAuthorizationConfig should have errored when no authorization modes are passed")
+	for _, tt := range tests {
+		_, err := NewAuthorizerFromAuthorizationConfig(tt.modes, tt.config)
+		if tt.wantErr && (err == nil) {
+			t.Errorf("NewAuthorizerFromAuthorizationConfig %s", tt.msg)
+		} else if !tt.wantErr && (err != nil) {
+			t.Errorf("NewAuthorizerFromAuthorizationConfig %s: %v", tt.msg, err)
+		}
 	}
 }
--- a/plugin/pkg/auth/authorizer/doc.go
+++ b/plugin/pkg/auth/authorizer/doc.go
@ -0,0 +1,18 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 authorizer contains implementations for pkg/auth/authorizer interfaces
+package authorizer
--- a/plugin/pkg/auth/authorizer/webhook/certs_test.go
+++ b/plugin/pkg/auth/authorizer/webhook/certs_test.go
@ -0,0 +1,211 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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.
+*/
+
+// This file was generated using openssl by the gencerts.sh script
+// and holds raw certificates for the webhook tests.
+
+package webhook
+
+var caKey = []byte(`-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`)
+
+var caCert = []byte(`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`)
+
+var badCAKey = []byte(`-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`)
+
+var badCACert = []byte(`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`)
+
+var serverKey = []byte(`-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`)
+
+var serverCert = []byte(`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`)
+
+var clientKey = []byte(`-----BEGIN RSA PRIVATE KEY-----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+-----END RSA PRIVATE KEY-----`)
+
+var clientCert = []byte(`-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----`)
--- a/plugin/pkg/auth/authorizer/webhook/gencerts.sh
+++ b/plugin/pkg/auth/authorizer/webhook/gencerts.sh
@ -0,0 +1,102 @@
+#!/bin/bash
+
+# Copyright 2016 The Kubernetes Authors All rights reserved.
+#
+# 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.
+
+set -e
+
+# gencerts.sh generates the certificates for the webhook authz plugin tests.
+# 
+# It is not expected to be run often (there is no go generate rule), and mainly
+# exists for documentation purposes.
+
+cat > server.conf << EOF
+[req]
+req_extensions = v3_req
+distinguished_name = req_distinguished_name
+[req_distinguished_name]
+[ v3_req ]
+basicConstraints = CA:FALSE
+keyUsage = nonRepudiation, digitalSignature, keyEncipherment
+extendedKeyUsage = serverAuth
+subjectAltName = @alt_names
+[alt_names]
+IP.1 = 127.0.0.1
+EOF
+
+cat > client.conf << EOF
+[req]
+req_extensions = v3_req
+distinguished_name = req_distinguished_name
+[req_distinguished_name]
+[ v3_req ]
+basicConstraints = CA:FALSE
+keyUsage = nonRepudiation, digitalSignature, keyEncipherment
+extendedKeyUsage = clientAuth
+EOF
+
+# Create a certificate authority
+openssl genrsa -out caKey.pem 2048
+openssl req -x509 -new -nodes -key caKey.pem -days 100000 -out caCert.pem -subj "/CN=webhook_authz_ca"
+
+# Create a second certificate authority
+openssl genrsa -out badCAKey.pem 2048
+openssl req -x509 -new -nodes -key badCAKey.pem -days 100000 -out badCACert.pem -subj "/CN=webhook_authz_ca"
+
+# Create a server certiticate
+openssl genrsa -out serverKey.pem 2048
+openssl req -new -key serverKey.pem -out server.csr -subj "/CN=webhook_authz_server" -config server.conf
+openssl x509 -req -in server.csr -CA caCert.pem -CAkey caKey.pem -CAcreateserial -out serverCert.pem -days 100000 -extensions v3_req -extfile server.conf
+
+# Create a client certiticate
+openssl genrsa -out clientKey.pem 2048
+openssl req -new -key clientKey.pem -out client.csr -subj "/CN=webhook_authz_client" -config client.conf
+openssl x509 -req -in client.csr -CA caCert.pem -CAkey caKey.pem -CAcreateserial -out clientCert.pem -days 100000 -extensions v3_req -extfile client.conf
+
+outfile=certs_test.go
+
+cat > $outfile << EOF
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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.
+*/
+
+EOF
+
+echo "// This file was generated using openssl by the gencerts.sh script" >> $outfile
+echo "// and holds raw certificates for the webhook tests." >> $outfile
+echo "" >> $outfile
+echo "package webhook" >> $outfile
+for file in caKey caCert badCAKey badCACert serverKey serverCert clientKey clientCert; do
+	data=$(cat ${file}.pem)
+	echo "" >> $outfile
+	echo "var $file = []byte(\`$data\`)" >> $outfile
+done
+
+# Clean up after we're done.
+rm *.pem
+rm *.csr
+rm *.srl
+rm *.conf
--- a/plugin/pkg/auth/authorizer/webhook/webhook.go
+++ b/plugin/pkg/auth/authorizer/webhook/webhook.go
@ -0,0 +1,180 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 webhook implements the authorizer.Authorizer interface using HTTP webhooks.
+package webhook
+
+import (
+	"errors"
+	"fmt"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/apimachinery/registered"
+	"k8s.io/kubernetes/pkg/apis/authorization/v1beta1"
+	"k8s.io/kubernetes/pkg/auth/authorizer"
+	client "k8s.io/kubernetes/pkg/client/unversioned"
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/runtime/serializer/json"
+	"k8s.io/kubernetes/pkg/runtime/serializer/versioning"
+
+	_ "k8s.io/kubernetes/pkg/apis/authorization/install"
+)
+
+var (
+	encodeVersions = []unversioned.GroupVersion{v1beta1.SchemeGroupVersion}
+	decodeVersions = []unversioned.GroupVersion{v1beta1.SchemeGroupVersion}
+
+	requireEnabled = []unversioned.GroupVersion{v1beta1.SchemeGroupVersion}
+)
+
+// Ensure Webhook implements the authorizer.Authorizer interface.
+var _ authorizer.Authorizer = (*WebhookAuthorizer)(nil)
+
+type WebhookAuthorizer struct {
+	restClient *client.RESTClient
+}
+
+// New creates a new WebhookAuthorizer from the provided kubeconfig file.
+//
+// The config's cluster field is used to refer to the remote service, user refers to the returned authorizer.
+//
+//     # clusters refers to the remote service.
+//     clusters:
+//     - name: name-of-remote-authz-service
+//       cluster:
+//         certificate-authority: /path/to/ca.pem      # CA for verifying the remote service.
+//         server: https://authz.example.com/authorize # URL of remote service to query. Must use 'https'.
+//
+//     # users refers to the API server's webhook configuration.
+//     users:
+//     - name: name-of-api-server
+//       user:
+//         client-certificate: /path/to/cert.pem # cert for the webhook plugin to use
+//         client-key: /path/to/key.pem          # key matching the cert
+//
+// For additional HTTP configuration, refer to the kubeconfig documentation
+// http://kubernetes.io/v1.1/docs/user-guide/kubeconfig-file.html.
+func New(kubeConfigFile string) (*WebhookAuthorizer, error) {
+
+	for _, groupVersion := range requireEnabled {
+		if !registered.IsEnabledVersion(groupVersion) {
+			return nil, fmt.Errorf("webhook authz plugin requires enabling extension resource: %s", groupVersion)
+		}
+	}
+
+	loadingRules := clientcmd.NewDefaultClientConfigLoadingRules()
+	loadingRules.ExplicitPath = kubeConfigFile
+	loader := clientcmd.NewNonInteractiveDeferredLoadingClientConfig(loadingRules, &clientcmd.ConfigOverrides{})
+
+	clientConfig, err := loader.ClientConfig()
+	if err != nil {
+		return nil, err
+	}
+	serializer := json.NewSerializer(json.DefaultMetaFactory, api.Scheme, runtime.ObjectTyperToTyper(api.Scheme), false)
+	clientConfig.ContentConfig.Codec = versioning.NewCodecForScheme(api.Scheme, serializer, encodeVersions, decodeVersions)
+
+	restClient, err := client.UnversionedRESTClientFor(clientConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO(ericchiang): Can we ensure remote service is reachable?
+
+	return &WebhookAuthorizer{restClient}, nil
+}
+
+// Authorize makes a REST request to the remote service describing the attempted action as a JSON
+// serialized api.authorization.v1beta1.SubjectAccessReview object. An example request body is
+// provided bellow.
+//
+//     {
+//       "apiVersion": "authorization.k8s.io/v1beta1",
+//       "kind": "SubjectAccessReview",
+//       "spec": {
+//         "resourceAttributes": {
+//           "namespace": "kittensandponies",
+//           "verb": "GET",
+//           "group": "group3",
+//           "resource": "pods"
+//         },
+//         "user": "jane",
+//         "group": [
+//           "group1",
+//           "group2"
+//         ]
+//       }
+//     }
+//
+// The remote service is expected to fill the SubjectAccessReviewStatus field to either allow or
+// disallow access. A permissive response would return:
+//
+//     {
+//       "apiVersion": "authorization.k8s.io/v1beta1",
+//       "kind": "SubjectAccessReview",
+//       "status": {
+//         "allowed": true
+//       }
+//     }
+//
+// To disallow access, the remote service would return:
+//
+//     {
+//       "apiVersion": "authorization.k8s.io/v1beta1",
+//       "kind": "SubjectAccessReview",
+//       "status": {
+//         "allowed": false,
+//         "reason": "user does not have read access to the namespace"
+//       }
+//     }
+//
+func (w *WebhookAuthorizer) Authorize(attr authorizer.Attributes) (err error) {
+	r := &v1beta1.SubjectAccessReview{
+		Spec: v1beta1.SubjectAccessReviewSpec{
+			User:   attr.GetUserName(),
+			Groups: attr.GetGroups(),
+		},
+	}
+	if attr.IsResourceRequest() {
+		r.Spec.ResourceAttributes = &v1beta1.ResourceAttributes{
+			Namespace: attr.GetNamespace(),
+			Verb:      attr.GetVerb(),
+			Group:     attr.GetAPIGroup(),
+			Resource:  attr.GetResource(),
+		}
+	} else {
+		r.Spec.NonResourceAttributes = &v1beta1.NonResourceAttributes{
+			Path: attr.GetPath(),
+			Verb: attr.GetVerb(),
+		}
+	}
+	result := w.restClient.Post().Body(r).Do()
+	if err := result.Error(); err != nil {
+		return err
+	}
+
+	if err := result.Into(r); err != nil {
+		return err
+	}
+	if r.Status.Allowed {
+		return nil
+	}
+	if r.Status.Reason != "" {
+		return errors.New(r.Status.Reason)
+	}
+	return errors.New("unauthorized")
+}
--- a/plugin/pkg/auth/authorizer/webhook/webhook_test.go
+++ b/plugin/pkg/auth/authorizer/webhook/webhook_test.go
@ -0,0 +1,473 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 webhook
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+	"text/template"
+
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/apis/authorization/v1beta1"
+	"k8s.io/kubernetes/pkg/auth/authorizer"
+	"k8s.io/kubernetes/pkg/auth/user"
+	"k8s.io/kubernetes/pkg/client/unversioned/clientcmd/api/v1"
+	"k8s.io/kubernetes/pkg/util"
+)
+
+func TestNewFromConfig(t *testing.T) {
+	dir, err := ioutil.TempDir("", "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(dir)
+
+	data := struct {
+		CA   string
+		Cert string
+		Key  string
+	}{
+		CA:   filepath.Join(dir, "ca.pem"),
+		Cert: filepath.Join(dir, "clientcert.pem"),
+		Key:  filepath.Join(dir, "clientkey.pem"),
+	}
+
+	files := []struct {
+		name string
+		data []byte
+	}{
+		{data.CA, caCert},
+		{data.Cert, clientCert},
+		{data.Key, clientKey},
+	}
+	for _, file := range files {
+		if err := ioutil.WriteFile(file.name, file.data, 0400); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	tests := []struct {
+		msg        string
+		configTmpl string
+		wantErr    bool
+	}{
+		{
+			msg: "a single cluster and single user",
+			configTmpl: `
+clusters:
+- cluster:
+    certificate-authority: {{ .CA }}
+    server: https://authz.example.com
+  name: foobar
+users:
+- name: a cluster
+  user:
+    client-certificate: {{ .Cert }}
+    client-key: {{ .Key }}
+`,
+			wantErr: false,
+		},
+		{
+			msg: "multiple clusters with no context",
+			configTmpl: `
+clusters:
+- cluster:
+    certificate-authority: {{ .CA }}
+    server: https://authz.example.com
+  name: foobar
+- cluster:
+    certificate-authority: a bad certificate path
+    server: https://authz.example.com
+  name: barfoo
+users:
+- name: a name
+  user:
+    client-certificate: {{ .Cert }}
+    client-key: {{ .Key }}
+`,
+			wantErr: false,
+		},
+		{
+			msg: "multiple clusters with a context",
+			configTmpl: `
+clusters:
+- cluster:
+    certificate-authority: a bad certificate path
+    server: https://authz.example.com
+  name: foobar
+- cluster:
+    certificate-authority: {{ .CA }}
+    server: https://authz.example.com
+  name: barfoo
+users:
+- name: a name
+  user:
+    client-certificate: {{ .Cert }}
+    client-key: {{ .Key }}
+contexts:
+- name: default
+  context:
+    cluster: barfoo
+    user: a name
+current-context: default
+`,
+			wantErr: false,
+		},
+		{
+			msg: "cluster with bad certificate path specified",
+			configTmpl: `
+clusters:
+- cluster:
+    certificate-authority: a bad certificate path
+    server: https://authz.example.com
+  name: foobar
+- cluster:
+    certificate-authority: {{ .CA }}
+    server: https://authz.example.com
+  name: barfoo
+users:
+- name: a name
+  user:
+    client-certificate: {{ .Cert }}
+    client-key: {{ .Key }}
+contexts:
+- name: default
+  context:
+    cluster: foobar
+    user: a name
+current-context: default
+`,
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		// Use a closure so defer statements trigger between loop iterations.
+		err := func() error {
+			tempfile, err := ioutil.TempFile("", "")
+			if err != nil {
+				return err
+			}
+			p := tempfile.Name()
+			defer os.Remove(p)
+
+			tmpl, err := template.New("test").Parse(tt.configTmpl)
+			if err != nil {
+				return fmt.Errorf("failed to parse test template: %v", err)
+			}
+			if err := tmpl.Execute(tempfile, data); err != nil {
+				return fmt.Errorf("failed to execute test template: %v", err)
+			}
+			// Create a new authorizer
+			_, err = New(p)
+			return err
+		}()
+		if err != nil && !tt.wantErr {
+			t.Errorf("failed to load plugin from config %q: %v", tt.msg, err)
+		}
+		if err == nil && tt.wantErr {
+			t.Errorf("wanted an error when loading config, did not get one: %q", tt.msg)
+		}
+	}
+}
+
+// Service mocks a remote service.
+type Service interface {
+	Review(*v1beta1.SubjectAccessReview)
+}
+
+// NewTestServer wraps a Service as an httptest.Server.
+func NewTestServer(s Service, cert, key, caCert []byte) (*httptest.Server, error) {
+	var tlsConfig *tls.Config
+	if cert != nil {
+		cert, err := tls.X509KeyPair(cert, key)
+		if err != nil {
+			return nil, err
+		}
+		tlsConfig = &tls.Config{Certificates: []tls.Certificate{cert}}
+	}
+
+	if caCert != nil {
+		rootCAs := x509.NewCertPool()
+		rootCAs.AppendCertsFromPEM(caCert)
+		if tlsConfig == nil {
+			tlsConfig = &tls.Config{}
+		}
+		tlsConfig.ClientCAs = rootCAs
+		tlsConfig.ClientAuth = tls.RequireAndVerifyClientCert
+	}
+
+	serveHTTP := func(w http.ResponseWriter, r *http.Request) {
+		var review v1beta1.SubjectAccessReview
+		if err := json.NewDecoder(r.Body).Decode(&review); err != nil {
+			http.Error(w, fmt.Sprintf("failed to decode body: %v", err), http.StatusBadRequest)
+			return
+		}
+		s.Review(&review)
+		type status struct {
+			Allowed bool   `json:"allowed"`
+			Reason  string `json:"reason"`
+		}
+		resp := struct {
+			APIVersion string `json:"apiVersion"`
+			Status     status `json:"status"`
+		}{
+			APIVersion: v1beta1.SchemeGroupVersion.String(),
+			Status:     status{review.Status.Allowed, review.Status.Reason},
+		}
+		w.Header().Set("Content-Type", "application/json")
+		json.NewEncoder(w).Encode(resp)
+	}
+
+	server := httptest.NewUnstartedServer(http.HandlerFunc(serveHTTP))
+	server.TLS = tlsConfig
+	server.StartTLS()
+	return server, nil
+}
+
+// A service that can be set to allow all or deny all authorization requests.
+type mockService struct {
+	allow bool
+}
+
+func (m *mockService) Review(r *v1beta1.SubjectAccessReview) {
+	r.Status.Allowed = m.allow
+}
+func (m *mockService) Allow() { m.allow = true }
+func (m *mockService) Deny()  { m.allow = false }
+
+// newAuthorizer creates a temporary kubeconfig file from the provided arguments and attempts to load
+// a new WebhookAuthorizer from it.
+func newAuthorizer(callbackURL string, clientCert, clientKey, ca []byte) (*WebhookAuthorizer, error) {
+	tempfile, err := ioutil.TempFile("", "")
+	if err != nil {
+		return nil, err
+	}
+	p := tempfile.Name()
+	defer os.Remove(p)
+	config := v1.Config{
+		Clusters: []v1.NamedCluster{
+			{
+				Cluster: v1.Cluster{Server: callbackURL, CertificateAuthorityData: ca},
+			},
+		},
+		AuthInfos: []v1.NamedAuthInfo{
+			{
+				AuthInfo: v1.AuthInfo{ClientCertificateData: clientCert, ClientKeyData: clientKey},
+			},
+		},
+	}
+	if err := json.NewEncoder(tempfile).Encode(config); err != nil {
+		return nil, err
+	}
+	return New(p)
+}
+
+func TestTLSConfig(t *testing.T) {
+	tests := []struct {
+		test                            string
+		clientCert, clientKey, clientCA []byte
+		serverCert, serverKey, serverCA []byte
+		wantErr                         bool
+	}{
+		{
+			test:       "TLS setup between client and server",
+			clientCert: clientCert, clientKey: clientKey, clientCA: caCert,
+			serverCert: serverCert, serverKey: serverKey, serverCA: caCert,
+		},
+		{
+			test:       "Server does not require client auth",
+			clientCA:   caCert,
+			serverCert: serverCert, serverKey: serverKey,
+		},
+		{
+			test:       "Server does not require client auth, client provides it",
+			clientCert: clientCert, clientKey: clientKey, clientCA: caCert,
+			serverCert: serverCert, serverKey: serverKey,
+		},
+		{
+			test:       "Client does not trust server",
+			clientCert: clientCert, clientKey: clientKey,
+			serverCert: serverCert, serverKey: serverKey,
+			wantErr: true,
+		},
+		{
+			test:       "Server does not trust client",
+			clientCert: clientCert, clientKey: clientKey, clientCA: caCert,
+			serverCert: serverCert, serverKey: serverKey, serverCA: badCACert,
+			wantErr: true,
+		},
+		{
+			// Plugin does not support insecure configurations.
+			test:    "Server is using insecure connection",
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		// Use a closure so defer statements trigger between loop iterations.
+		func() {
+			service := new(mockService)
+
+			server, err := NewTestServer(service, tt.serverCert, tt.serverKey, tt.serverCA)
+			if err != nil {
+				t.Errorf("%s: failed to create server: %v", tt.test, err)
+				return
+			}
+			defer server.Close()
+
+			wh, err := newAuthorizer(server.URL, tt.clientCert, tt.clientKey, tt.clientCA)
+			if err != nil {
+				t.Errorf("%s: failed to create client: %v", tt.test, err)
+				return
+			}
+
+			attr := authorizer.AttributesRecord{User: &user.DefaultInfo{}}
+
+			// Allow all and see if we get an error.
+			service.Allow()
+			err = wh.Authorize(attr)
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("expected error making authorization request: %v", err)
+				}
+				return
+			}
+			if err != nil {
+				t.Errorf("%s: failed to authorize with AllowAll policy: %v", tt.test, err)
+				return
+			}
+
+			service.Deny()
+			if err := wh.Authorize(attr); err == nil {
+				t.Errorf("%s: incorrectly authorized with DenyAll policy", tt.test)
+			}
+		}()
+	}
+}
+
+// recorderService records all access review requests.
+type recorderService struct {
+	last v1beta1.SubjectAccessReview
+	err  error
+}
+
+func (rec *recorderService) Review(r *v1beta1.SubjectAccessReview) {
+	rec.last = v1beta1.SubjectAccessReview{}
+	rec.last = *r
+	r.Status.Allowed = true
+}
+
+func (rec *recorderService) Last() (v1beta1.SubjectAccessReview, error) {
+	return rec.last, rec.err
+}
+
+func TestWebhook(t *testing.T) {
+	serv := new(recorderService)
+	s, err := NewTestServer(serv, serverCert, serverKey, caCert)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer s.Close()
+
+	wh, err := newAuthorizer(s.URL, clientCert, clientKey, caCert)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expTypeMeta := unversioned.TypeMeta{
+		APIVersion: "authorization.k8s.io/v1beta1",
+		Kind:       "SubjectAccessReview",
+	}
+
+	tests := []struct {
+		attr authorizer.Attributes
+		want v1beta1.SubjectAccessReview
+	}{
+		{
+			attr: authorizer.AttributesRecord{User: &user.DefaultInfo{}},
+			want: v1beta1.SubjectAccessReview{
+				TypeMeta: expTypeMeta,
+				Spec: v1beta1.SubjectAccessReviewSpec{
+					NonResourceAttributes: &v1beta1.NonResourceAttributes{},
+				},
+			},
+		},
+		{
+			attr: authorizer.AttributesRecord{User: &user.DefaultInfo{Name: "jane"}},
+			want: v1beta1.SubjectAccessReview{
+				TypeMeta: expTypeMeta,
+				Spec: v1beta1.SubjectAccessReviewSpec{
+					User: "jane",
+					NonResourceAttributes: &v1beta1.NonResourceAttributes{},
+				},
+			},
+		},
+		{
+			attr: authorizer.AttributesRecord{
+				User: &user.DefaultInfo{
+					Name:   "jane",
+					UID:    "1",
+					Groups: []string{"group1", "group2"},
+				},
+				Verb:            "GET",
+				Namespace:       "kittensandponies",
+				APIGroup:        "group3",
+				Resource:        "pods",
+				ResourceRequest: true,
+				Path:            "/foo",
+			},
+			want: v1beta1.SubjectAccessReview{
+				TypeMeta: expTypeMeta,
+				Spec: v1beta1.SubjectAccessReviewSpec{
+					User:   "jane",
+					Groups: []string{"group1", "group2"},
+					ResourceAttributes: &v1beta1.ResourceAttributes{
+						Verb:      "GET",
+						Namespace: "kittensandponies",
+						Group:     "group3",
+						Resource:  "pods",
+					},
+				},
+			},
+		},
+	}
+
+	for i, tt := range tests {
+		if err := wh.Authorize(tt.attr); err != nil {
+			t.Errorf("case %d: authorization failed: %v", i, err)
+			continue
+		}
+
+		gotAttr, err := serv.Last()
+		if err != nil {
+			t.Errorf("case %d: failed to deserialize webhook request: %v", i, err)
+			continue
+		}
+		if !reflect.DeepEqual(gotAttr, tt.want) {
+			t.Errorf("case %d: got != want:\n%s", i, util.ObjectGoPrintDiff(gotAttr, tt.want))
+		}
+	}
+}