x509 request authenticator

cmd/kube-apiserver/apiserver.go

@@ -19,6 +19,7 @@ limitations under the License.
 package main
 
 import (
+	"crypto/tls"
 	"flag"
 	"net"
 	"net/http"
@@ -222,6 +223,11 @@ func main() {
 			ReadTimeout:    5 * time.Minute,
 			WriteTimeout:   5 * time.Minute,
 			MaxHeaderBytes: 1 << 20,
+			TLSConfig: &tls.Config{
+				// Populate PeerCertificates in requests, but don't reject connections without certificates
+				// This allows certificates to be validated by authenticators, while still allowing other auth types
+				ClientAuth: tls.RequestClientCert,
+			},
 		}
 		glog.Infof("Serving securely on %s", secureLocation)
 		go func() {

plugin/pkg/auth/authenticator/request/x509/doc.go

@@ -0,0 +1,19 @@
+/*
+Copyright 2014 Google Inc. 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 x509 provides a request authenticator that validates and
+// extracts user information from client certificates
+package x509

plugin/pkg/auth/authenticator/request/x509/x509.go

@@ -0,0 +1,111 @@
+/*
+Copyright 2014 Google Inc. 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 x509
+
+import (
+	"crypto/x509"
+	"net/http"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/user"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+)
+
+// UserConversion defines an interface for extracting user info from a client certificate chain
+type UserConversion interface {
+	User(chain []*x509.Certificate) (user.Info, bool, error)
+}
+
+// UserConversionFunc is a function that implements the UserConversion interface.
+type UserConversionFunc func(chain []*x509.Certificate) (user.Info, bool, error)
+
+// User implements x509.UserConversion
+func (f UserConversionFunc) User(chain []*x509.Certificate) (user.Info, bool, error) {
+	return f(chain)
+}
+
+// Authenticator implements request.Authenticator by extracting user info from verified client certificates
+type Authenticator struct {
+	opts x509.VerifyOptions
+	user UserConversion
+}
+
+// New returns a request.Authenticator that verifies client certificates using the provided
+// VerifyOptions, and converts valid certificate chains into user.Info using the provided UserConversion
+func New(opts x509.VerifyOptions, user UserConversion) *Authenticator {
+	return &Authenticator{opts, user}
+}
+
+// AuthenticateRequest authenticates the request using presented client certificates
+func (a *Authenticator) AuthenticateRequest(req *http.Request) (user.Info, bool, error) {
+	if req.TLS == nil {
+		return nil, false, nil
+	}
+
+	var errors util.ErrorList
+	for _, cert := range req.TLS.PeerCertificates {
+		chains, err := cert.Verify(a.opts)
+		if err != nil {
+			errors = append(errors, err)
+			continue
+		}
+
+		for _, chain := range chains {
+			user, ok, err := a.user.User(chain)
+			if err != nil {
+				errors = append(errors, err)
+				continue
+			}
+
+			if ok {
+				return user, ok, err
+			}
+		}
+	}
+	return nil, false, errors.ToError()
+}
+
+// DefaultVerifyOptions returns VerifyOptions that use the system root certificates, current time,
+// and requires certificates to be valid for client auth (x509.ExtKeyUsageClientAuth)
+func DefaultVerifyOptions() x509.VerifyOptions {
+	return x509.VerifyOptions{
+		KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+	}
+}
+
+// CommonNameUserConversion builds user info from a certificate chain using the subject's CommonName
+var CommonNameUserConversion = UserConversionFunc(func(chain []*x509.Certificate) (user.Info, bool, error) {
+	if len(chain[0].Subject.CommonName) == 0 {
+		return nil, false, nil
+	}
+	return &user.DefaultInfo{Name: chain[0].Subject.CommonName}, true, nil
+})
+
+// DNSNameUserConversion builds user info from a certificate chain using the first DNSName on the certificate
+var DNSNameUserConversion = UserConversionFunc(func(chain []*x509.Certificate) (user.Info, bool, error) {
+	if len(chain[0].DNSNames) == 0 {
+		return nil, false, nil
+	}
+	return &user.DefaultInfo{Name: chain[0].DNSNames[0]}, true, nil
+})
+
+// EmailAddressUserConversion builds user info from a certificate chain using the first EmailAddress on the certificate
+var EmailAddressUserConversion = UserConversionFunc(func(chain []*x509.Certificate) (user.Info, bool, error) {
+	if len(chain[0].EmailAddresses) == 0 {
+		return nil, false, nil
+	}
+	return &user.DefaultInfo{Name: chain[0].EmailAddresses[0]}, true, nil
+})