Add Clone() and OverrideServerName() to TransportCredentials

credentials/credentials.go

@@ -109,6 +109,12 @@ type TransportCredentials interface {
 	ServerHandshake(net.Conn) (net.Conn, AuthInfo, error)
 	// Info provides the ProtocolInfo of this TransportCredentials.
 	Info() ProtocolInfo
+	// Clone makes a copy of this TransportCredentials.
+	Clone() TransportCredentials
+	// OverrideServerName overrides the server name used to verify the hostname on the returned certificates from the server.
+	// gRPC internals also use it to override the virtual hosting name if it is set.
+	// It must be called before dialing. Currently, this is only used by grpclb.
+	OverrideServerName(string) error
 }
 
 // TLSInfo contains the auth information for a TLS authenticated connection.
@@ -136,16 +142,6 @@ func (c tlsCreds) Info() ProtocolInfo {
 	}
 }
 
-// GetRequestMetadata returns nil, nil since TLS credentials does not have
-// metadata.
-func (c *tlsCreds) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
-	return nil, nil
-}
-
-func (c *tlsCreds) RequireTransportSecurity() bool {
-	return true
-}
-
 func (c *tlsCreds) ClientHandshake(ctx context.Context, addr string, rawConn net.Conn) (_ net.Conn, _ AuthInfo, err error) {
 	// use local cfg to avoid clobbering ServerName if using multiple endpoints
 	cfg := cloneTLSConfig(c.config)
@@ -182,6 +178,15 @@ func (c *tlsCreds) ServerHandshake(rawConn net.Conn) (net.Conn, AuthInfo, error)
 	return conn, TLSInfo{conn.ConnectionState()}, nil
 }
 
+func (c *tlsCreds) Clone() TransportCredentials {
+	return NewTLS(c.config)
+}
+
+func (c *tlsCreds) OverrideServerName(serverNameOverride string) error {
+	c.config.ServerName = serverNameOverride
+	return nil
+}
+
 // NewTLS uses c to construct a TransportCredentials based on TLS.
 func NewTLS(c *tls.Config) TransportCredentials {
 	tc := &tlsCreds{cloneTLSConfig(c)}
@@ -190,16 +195,16 @@ func NewTLS(c *tls.Config) TransportCredentials {
 }
 
 // NewClientTLSFromCert constructs a TLS from the input certificate for client.
-// serverNameOverwrite is for testing only. If set to a non empty string,
+// serverNameOverride is for testing only. If set to a non empty string,
-// it will overwrite the virtual host name of authority (e.g. :authority header field) in requests.
+// it will override the virtual host name of authority (e.g. :authority header field) in requests.
-func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverwrite string) TransportCredentials {
+func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverride string) TransportCredentials {
-	return NewTLS(&tls.Config{ServerName: serverNameOverwrite, RootCAs: cp})
+	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp})
 }
 
 // NewClientTLSFromFile constructs a TLS from the input certificate file for client.
-// serverNameOverwrite is for testing only. If set to a non empty string,
+// serverNameOverride is for testing only. If set to a non empty string,
-// it will overwrite the virtual host name of authority (e.g. :authority header field) in requests.
+// it will override the virtual host name of authority (e.g. :authority header field) in requests.
-func NewClientTLSFromFile(certFile, serverNameOverwrite string) (TransportCredentials, error) {
+func NewClientTLSFromFile(certFile, serverNameOverride string) (TransportCredentials, error) {
 	b, err := ioutil.ReadFile(certFile)
 	if err != nil {
 		return nil, err
@@ -208,7 +213,7 @@ func NewClientTLSFromFile(certFile, serverNameOverwrite string) (TransportCreden
 	if !cp.AppendCertsFromPEM(b) {
 		return nil, fmt.Errorf("credentials: failed to append certificates")
 	}
-	return NewTLS(&tls.Config{ServerName: serverNameOverwrite, RootCAs: cp}), nil
+	return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp}), nil
 }
 
 // NewServerTLSFromCert constructs a TLS from the input certificate for server.

credentials/credentials_test.go

@@ -0,0 +1,61 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package credentials
+
+import (
+	"testing"
+)
+
+func TestTLSOverrideServerName(t *testing.T) {
+	expectedServerName := "server.name"
+	c := NewTLS(nil)
+	c.OverrideServerName(expectedServerName)
+	if c.Info().ServerName != expectedServerName {
+		t.Fatalf("c.Info().ServerName = %v, want %v", c.Info().ServerName, expectedServerName)
+	}
+}
+
+func TestTLSClone(t *testing.T) {
+	expectedServerName := "server.name"
+	c := NewTLS(nil)
+	c.OverrideServerName(expectedServerName)
+	cc := c.Clone()
+	if cc.Info().ServerName != expectedServerName {
+		t.Fatalf("cc.Info().ServerName = %v, want %v", cc.Info().ServerName, expectedServerName)
+	}
+	cc.OverrideServerName("")
+	if c.Info().ServerName != expectedServerName {
+		t.Fatalf("Change in clone should not affect the original, c.Info().ServerName = %v, want %v", c.Info().ServerName, expectedServerName)
+	}
+}

test/end2end_test.go

@@ -2450,6 +2450,12 @@ func (c clientAlwaysFailCred) ServerHandshake(rawConn net.Conn) (net.Conn, crede
 func (c clientAlwaysFailCred) Info() credentials.ProtocolInfo {
 	return credentials.ProtocolInfo{}
 }
+func (c clientAlwaysFailCred) Clone() credentials.TransportCredentials {
+	return nil
+}
+func (c clientAlwaysFailCred) OverrideServerName(s string) error {
+	return nil
+}
 
 func TestDialWithBlockErrorOnBadCertificates(t *testing.T) {
 	te := newTest(t, env{name: "bad-cred", network: "tcp", security: "clientAlwaysFailCred", balancer: true})
@@ -2520,6 +2526,12 @@ func (c *clientTimeoutCreds) ServerHandshake(rawConn net.Conn) (net.Conn, creden
 func (c *clientTimeoutCreds) Info() credentials.ProtocolInfo {
 	return credentials.ProtocolInfo{}
 }
+func (c *clientTimeoutCreds) Clone() credentials.TransportCredentials {
+	return nil
+}
+func (c *clientTimeoutCreds) OverrideServerName(s string) error {
+	return nil
+}
 
 func TestNonFailFastRPCSucceedOnTimeoutCreds(t *testing.T) {
 	te := newTest(t, env{name: "timeout-cred", network: "tcp", security: "clientTimeoutCreds", balancer: false})
@@ -2556,6 +2568,12 @@ func (c *serverDispatchCred) ServerHandshake(rawConn net.Conn) (net.Conn, creden
 func (c *serverDispatchCred) Info() credentials.ProtocolInfo {
 	return credentials.ProtocolInfo{}
 }
+func (c *serverDispatchCred) Clone() credentials.TransportCredentials {
+	return nil
+}
+func (c *serverDispatchCred) OverrideServerName(s string) error {
+	return nil
+}
 func (c *serverDispatchCred) getRawConn() net.Conn {
 	<-c.ready
 	return c.rawConn