Prevent auth recursion for service account tokens

cmd/kube-apiserver/app/server.go

@@ -300,7 +300,7 @@ func (s *APIServer) Run(_ []string) error {
 	if s.ServiceAccountKeyFile == "" && s.TLSPrivateKeyFile != "" {
 		s.ServiceAccountKeyFile = s.TLSPrivateKeyFile
 	}
-	authenticator, err := apiserver.NewAuthenticator(s.BasicAuthFile, s.ClientCAFile, s.TokenAuthFile, s.ServiceAccountKeyFile, s.ServiceAccountLookup, client)
+	authenticator, err := apiserver.NewAuthenticator(s.BasicAuthFile, s.ClientCAFile, s.TokenAuthFile, s.ServiceAccountKeyFile, s.ServiceAccountLookup, helper)
 	if err != nil {
 		glog.Fatalf("Invalid Authentication Config: %v", err)
 	}

pkg/apiserver/authn.go

@@ -21,8 +21,8 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/authenticator"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/authenticator/bearertoken"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/serviceaccount"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/auth/authenticator/password/passwordfile"
 	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/auth/authenticator/request/basicauth"
@@ -32,7 +32,7 @@ import (
 )
 
 // NewAuthenticator returns an authenticator.Request or an error
-func NewAuthenticator(basicAuthFile, clientCAFile, tokenFile, serviceAccountKeyFile string, serviceAccountLookup bool, client client.Interface) (authenticator.Request, error) {
+func NewAuthenticator(basicAuthFile, clientCAFile, tokenFile, serviceAccountKeyFile string, serviceAccountLookup bool, helper tools.EtcdHelper) (authenticator.Request, error) {
 	var authenticators []authenticator.Request
 
 	if len(basicAuthFile) > 0 {
@@ -60,7 +60,7 @@ func NewAuthenticator(basicAuthFile, clientCAFile, tokenFile, serviceAccountKeyF
 	}
 
 	if len(serviceAccountKeyFile) > 0 {
-		serviceAccountAuth, err := newServiceAccountAuthenticator(serviceAccountKeyFile, serviceAccountLookup, client)
+		serviceAccountAuth, err := newServiceAccountAuthenticator(serviceAccountKeyFile, serviceAccountLookup, helper)
 		if err != nil {
 			return nil, err
 		}
@@ -98,12 +98,20 @@ func newAuthenticatorFromTokenFile(tokenAuthFile string) (authenticator.Request,
 }
 
 // newServiceAccountAuthenticator returns an authenticator.Request or an error
-func newServiceAccountAuthenticator(keyfile string, lookup bool, client client.Interface) (authenticator.Request, error) {
+func newServiceAccountAuthenticator(keyfile string, lookup bool, helper tools.EtcdHelper) (authenticator.Request, error) {
 	publicKey, err := serviceaccount.ReadPublicKey(keyfile)
 	if err != nil {
 		return nil, err
 	}
-	tokenAuthenticator := serviceaccount.JWTTokenAuthenticator([]*rsa.PublicKey{publicKey}, lookup, client)
+
+	var serviceAccountGetter serviceaccount.ServiceAccountTokenGetter
+	if lookup {
+		// If we need to look up service accounts and tokens,
+		// go directly to etcd to avoid recursive auth insanity
+		serviceAccountGetter = serviceaccount.NewGetterFromEtcdHelper(helper)
+	}
+
+	tokenAuthenticator := serviceaccount.JWTTokenAuthenticator([]*rsa.PublicKey{publicKey}, lookup, serviceAccountGetter)
 	return bearertoken.New(tokenAuthenticator), nil
 }
 

pkg/serviceaccount/jwt.go

@@ -29,7 +29,6 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/authenticator"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/user"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 )
 
 const (
@@ -124,15 +123,15 @@ func (j *jwtTokenGenerator) GenerateToken(serviceAccount api.ServiceAccount, sec
 
 // JWTTokenAuthenticator authenticates tokens as JWT tokens produced by JWTTokenGenerator
 // Token signatures are verified using each of the given public keys until one works (allowing key rotation)
-// If lookup is true, the service account and secret referenced as claims inside the token are retrieved and verified using the given client
+// If lookup is true, the service account and secret referenced as claims inside the token are retrieved and verified with the provided ServiceAccountTokenGetter
-func JWTTokenAuthenticator(keys []*rsa.PublicKey, lookup bool, client client.Interface) authenticator.Token {
+func JWTTokenAuthenticator(keys []*rsa.PublicKey, lookup bool, getter ServiceAccountTokenGetter) authenticator.Token {
-	return &jwtTokenAuthenticator{keys, lookup, client}
+	return &jwtTokenAuthenticator{keys, lookup, getter}
 }
 
 type jwtTokenAuthenticator struct {
 	keys   []*rsa.PublicKey
 	lookup bool
-	client client.Interface
+	getter ServiceAccountTokenGetter
 }
 
 func (j *jwtTokenAuthenticator) AuthenticateToken(token string) (user.Info, bool, error) {
@@ -199,7 +198,7 @@ func (j *jwtTokenAuthenticator) AuthenticateToken(token string) (user.Info, bool
 
 		if j.lookup {
 			// Make sure token hasn't been invalidated by deletion of the secret
-			secret, err := j.client.Secrets(namespace).Get(secretName)
+			secret, err := j.getter.GetSecret(namespace, secretName)
 			if err != nil {
 				return nil, false, errors.New("Token has been invalidated")
 			}
@@ -208,7 +207,7 @@ func (j *jwtTokenAuthenticator) AuthenticateToken(token string) (user.Info, bool
 			}
 
 			// Make sure service account still exists (name and UID)
-			serviceAccount, err := j.client.ServiceAccounts(namespace).Get(serviceAccountName)
+			serviceAccount, err := j.getter.GetServiceAccount(namespace, serviceAccountName)
 			if err != nil {
 				return nil, false, err
 			}

pkg/serviceaccount/jwt_test.go

@@ -214,7 +214,8 @@ func TestTokenGenerateAndValidate(t *testing.T) {
 	}
 
 	for k, tc := range testCases {
-		authenticator := JWTTokenAuthenticator(tc.Keys, tc.Client != nil, tc.Client)
+		getter := NewGetterFromClient(tc.Client)
+		authenticator := JWTTokenAuthenticator(tc.Keys, tc.Client != nil, getter)
 
 		user, ok, err := authenticator.AuthenticateToken(token)
 		if (err != nil) != tc.ExpectedErr {

pkg/serviceaccount/tokengetter.go

@@ -0,0 +1,81 @@
+/*
+Copyright 2014 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 serviceaccount
+
+import (
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/secret"
+	secretetcd "github.com/GoogleCloudPlatform/kubernetes/pkg/registry/secret/etcd"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/serviceaccount"
+	serviceaccountetcd "github.com/GoogleCloudPlatform/kubernetes/pkg/registry/serviceaccount/etcd"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
+)
+
+// ServiceAccountTokenGetter defines functions to retrieve a named service account and secret
+type ServiceAccountTokenGetter interface {
+	GetServiceAccount(namespace, name string) (*api.ServiceAccount, error)
+	GetSecret(namespace, name string) (*api.Secret, error)
+}
+
+// clientGetter implements ServiceAccountTokenGetter using a client.Interface
+type clientGetter struct {
+	client client.Interface
+}
+
+// NewGetterFromClient returns a ServiceAccountTokenGetter that
+// uses the specified client to retrieve service accounts and secrets.
+// The client should NOT authenticate using a service account token
+// the returned getter will be used to retrieve, or recursion will result.
+func NewGetterFromClient(c client.Interface) ServiceAccountTokenGetter {
+	return clientGetter{c}
+}
+func (c clientGetter) GetServiceAccount(namespace, name string) (*api.ServiceAccount, error) {
+	return c.client.ServiceAccounts(namespace).Get(name)
+}
+func (c clientGetter) GetSecret(namespace, name string) (*api.Secret, error) {
+	return c.client.Secrets(namespace).Get(name)
+}
+
+// registryGetter implements ServiceAccountTokenGetter using a service account and secret registry
+type registryGetter struct {
+	serviceAccounts serviceaccount.Registry
+	secrets         secret.Registry
+}
+
+// NewGetterFromRegistries returns a ServiceAccountTokenGetter that
+// uses the specified registries to retrieve service accounts and secrets.
+func NewGetterFromRegistries(serviceAccounts serviceaccount.Registry, secrets secret.Registry) ServiceAccountTokenGetter {
+	return &registryGetter{serviceAccounts, secrets}
+}
+func (r *registryGetter) GetServiceAccount(namespace, name string) (*api.ServiceAccount, error) {
+	ctx := api.WithNamespace(api.NewContext(), namespace)
+	return r.serviceAccounts.GetServiceAccount(ctx, name)
+}
+func (r *registryGetter) GetSecret(namespace, name string) (*api.Secret, error) {
+	ctx := api.WithNamespace(api.NewContext(), namespace)
+	return r.secrets.GetSecret(ctx, name)
+}
+
+// NewGetterFromEtcdHelper returns a ServiceAccountTokenGetter that
+// uses the specified helper to retrieve service accounts and secrets.
+func NewGetterFromEtcdHelper(helper tools.EtcdHelper) ServiceAccountTokenGetter {
+	return NewGetterFromRegistries(
+		serviceaccount.NewRegistry(serviceaccountetcd.NewStorage(helper)),
+		secret.NewRegistry(secretetcd.NewStorage(helper)),
+	)
+}

test/integration/service_account_test.go

@@ -366,7 +366,8 @@ func startServiceAccountTestServer(t *testing.T) (*client.Client, client.Config,
 		return nil, false, nil
 	})
 	serviceAccountKey, err := rsa.GenerateKey(rand.Reader, 2048)
-	serviceAccountTokenAuth := serviceaccount.JWTTokenAuthenticator([]*rsa.PublicKey{&serviceAccountKey.PublicKey}, true, rootClient)
+	serviceAccountTokenGetter := serviceaccount.NewGetterFromClient(rootClient)
+	serviceAccountTokenAuth := serviceaccount.JWTTokenAuthenticator([]*rsa.PublicKey{&serviceAccountKey.PublicKey}, true, serviceAccountTokenGetter)
 	authenticator := union.New(
 		bearertoken.New(rootTokenAuth),
 		bearertoken.New(serviceAccountTokenAuth),