/*
*
* Copyright 2014 gRPC 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 credentials implements various credentials supported by gRPC library,
// which encapsulate all the state needed by a client to authenticate with a
// server and make various assertions, e.g., about the client's identity, role,
// or whether it is authorized to make a particular call.
package credentials // import "google.golang.org/grpc/credentials"
import (
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"io/ioutil"
"net"
"strings"
"golang.org/x/net/context"
)
var (
// alpnProtoStr are the specified application level protocols for gRPC.
alpnProtoStr = []string{"h2"}
)
// PerRPCCredentials defines the common interface for the credentials which need to
// attach security information to every RPC (e.g., oauth2).
type PerRPCCredentials interface {
// GetRequestMetadata gets the current request metadata, refreshing
// tokens if required. This should be called by the transport layer on
// each request, and the data should be populated in headers or other
// context. uri is the URI of the entry point for the request. When
// supported by the underlying implementation, ctx can be used for
// timeout and cancellation.
// TODO(zhaoq): Define the set of the qualified keys instead of leaving
// it as an arbitrary string.
GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error)
// RequireTransportSecurity indicates whether the credentials requires
// transport security.
RequireTransportSecurity() bool
}
// ProtocolInfo provides information regarding the gRPC wire protocol version,
// security protocol, security protocol version in use, server name, etc.
type ProtocolInfo struct {
// ProtocolVersion is the gRPC wire protocol version.
ProtocolVersion string
// SecurityProtocol is the security protocol in use.
SecurityProtocol string
// SecurityVersion is the security protocol version.
SecurityVersion string
// ServerName is the user-configured server name.
ServerName string
}
// AuthInfo defines the common interface for the auth information the users are interested in.
type AuthInfo interface {
AuthType() string
}
var (
// ErrConnDispatched indicates that rawConn has been dispatched out of gRPC
// and the caller should not close rawConn.
ErrConnDispatched = errors.New("credentials: rawConn is dispatched out of gRPC")
)
// TransportCredentials defines the common interface for all the live gRPC wire
// protocols and supported transport security protocols (e.g., TLS, SSL).
type TransportCredentials interface {
// ClientHandshake does the authentication handshake specified by the corresponding
// authentication protocol on rawConn for clients. It returns the authenticated
// connection and the corresponding auth information about the connection.
// Implementations must use the provided context to implement timely cancellation.
// gRPC will try to reconnect if the error returned is a temporary error
// (io.EOF, context.DeadlineExceeded or err.Temporary() == true).
// If the returned error is a wrapper error, implementations should make sure that
// the error implements Temporary() to have the correct retry behaviors.
ClientHandshake(context.Context, string, net.Conn) (net.Conn, AuthInfo, error)
// ServerHandshake does the authentication handshake for servers. It returns
// the authenticated connection and the corresponding auth information about
// the connection.
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.
// It implements the AuthInfo interface.
type TLSInfo struct {
State tls.ConnectionState
}
// AuthType returns the type of TLSInfo as a string.
func (t TLSInfo) AuthType() string {
return "tls"
}
// tlsCreds is the credentials required for authenticating a connection using TLS.
type tlsCreds struct {
// TLS configuration
config *tls.Config
}
func (c tlsCreds) Info() ProtocolInfo {
return ProtocolInfo{
SecurityProtocol: "tls",
SecurityVersion: "1.2",
ServerName: c.config.ServerName,
}
}
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)
if cfg.ServerName == "" {
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
cfg.ServerName = addr[:colonPos]
}
conn := tls.Client(rawConn, cfg)
errChannel := make(chan error, 1)
go func() {
errChannel <- conn.Handshake()
}()
select {
case err := <-errChannel:
if err != nil {
return nil, nil, err
}
case <-ctx.Done():
return nil, nil, ctx.Err()
}
return conn, TLSInfo{conn.ConnectionState()}, nil
}
func (c *tlsCreds) ServerHandshake(rawConn net.Conn) (net.Conn, AuthInfo, error) {
conn := tls.Server(rawConn, c.config)
if err := conn.Handshake(); err != nil {
return nil, nil, err
}
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)}
tc.config.NextProtos = alpnProtoStr
return tc
}
// NewClientTLSFromCert constructs TLS credentials from the input certificate for client.
// serverNameOverride is for testing only. If set to a non empty string,
// it will override the virtual host name of authority (e.g. :authority header field) in requests.
func NewClientTLSFromCert(cp *x509.CertPool, serverNameOverride string) TransportCredentials {
return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp})
}
// NewClientTLSFromFile constructs TLS credentials from the input certificate file for client.
// serverNameOverride is for testing only. If set to a non empty string,
// it will override the virtual host name of authority (e.g. :authority header field) in requests.
func NewClientTLSFromFile(certFile, serverNameOverride string) (TransportCredentials, error) {
b, err := ioutil.ReadFile(certFile)
if err != nil {
return nil, err
}
cp := x509.NewCertPool()
if !cp.AppendCertsFromPEM(b) {
return nil, fmt.Errorf("credentials: failed to append certificates")
}
return NewTLS(&tls.Config{ServerName: serverNameOverride, RootCAs: cp}), nil
}
// NewServerTLSFromCert constructs TLS credentials from the input certificate for server.
func NewServerTLSFromCert(cert *tls.Certificate) TransportCredentials {
return NewTLS(&tls.Config{Certificates: []tls.Certificate{*cert}})
}
// NewServerTLSFromFile constructs TLS credentials from the input certificate file and key
// file for server.
func NewServerTLSFromFile(certFile, keyFile string) (TransportCredentials, error) {
cert, err := tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
return nil, err
}
return NewTLS(&tls.Config{Certificates: []tls.Certificate{cert}}), nil
}
