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/*
*
* Copyright 2014, 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,
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* 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 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"
"fmt"
"io/ioutil"
"net"
"strings"
"time"
"golang.org/x/net/context"
)
var (
// alpnProtoStr are the specified application level protocols for gRPC.
alpnProtoStr = []string{"h2"}
)
// Credentials defines the common interface all supported credentials must
// implement.
type Credentials 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 credentails requires
// transport security.
RequireTransportSecurity() bool
}
// ProtocolInfo provides information regarding the gRPC wire protocol version,
// security protocol, security protocol version in use, 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
}
// AuthInfo defines the common interface for the auth information the users are interested in.
type AuthInfo interface {
AuthType() string
}
type authInfoKey struct{}
// NewContext creates a new context with authInfo attached.
func NewContext(ctx context.Context, authInfo AuthInfo) context.Context {
return context.WithValue(ctx, authInfoKey{}, authInfo)
}
// FromContext returns the authInfo in ctx if it exists.
func FromContext(ctx context.Context) (authInfo AuthInfo, ok bool) {
authInfo, ok = ctx.Value(authInfoKey{}).(AuthInfo)
return
}
// TransportAuthenticator defines the common interface for all the live gRPC wire
// protocols and supported transport security protocols (e.g., TLS, SSL).
type TransportAuthenticator 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.
ClientHandshake(addr string, rawConn net.Conn, timeout time.Duration) (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(rawConn net.Conn) (net.Conn, AuthInfo, error)
// Info provides the ProtocolInfo of this TransportAuthenticator.
Info() ProtocolInfo
Credentials
}
// TLSInfo contains the auth information for a TLS authenticated connection.
// It implements the AuthInfo interface.
type TLSInfo struct {
State tls.ConnectionState
}
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",
}
}
// 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
}
type timeoutError struct{}
func (timeoutError) Error() string { return "credentials: Dial timed out" }
func (timeoutError) Timeout() bool { return true }
func (timeoutError) Temporary() bool { return true }
func (c *tlsCreds) ClientHandshake(addr string, rawConn net.Conn, timeout time.Duration) (_ net.Conn, _ AuthInfo, err error) {
// borrow some code from tls.DialWithDialer
var errChannel chan error
if timeout != 0 {
errChannel = make(chan error, 2)
time.AfterFunc(timeout, func() {
errChannel <- timeoutError{}
})
}
if c.config.ServerName == "" {
colonPos := strings.LastIndex(addr, ":")
if colonPos == -1 {
colonPos = len(addr)
}
c.config.ServerName = addr[:colonPos]
}
conn := tls.Client(rawConn, &c.config)
if timeout == 0 {
err = conn.Handshake()
} else {
go func() {
errChannel <- conn.Handshake()
}()
err = <-errChannel
}
if err != nil {
rawConn.Close()
return nil, nil, err
}
// TODO(zhaoq): Omit the auth info for client now. It is more for
// information than anything else.
return conn, nil, nil
}
func (c *tlsCreds) ServerHandshake(rawConn net.Conn) (net.Conn, AuthInfo, error) {
conn := tls.Server(rawConn, &c.config)
if err := conn.Handshake(); err != nil {
rawConn.Close()
return nil, nil, err
}
return conn, TLSInfo{conn.ConnectionState()}, nil
}
// NewTLS uses c to construct a TransportAuthenticator based on TLS.
func NewTLS(c *tls.Config) TransportAuthenticator {
tc := &tlsCreds{*c}
tc.config.NextProtos = alpnProtoStr
return tc
}
// NewClientTLSFromCert constructs a TLS from the input certificate for client.
func NewClientTLSFromCert(cp *x509.CertPool, serverName string) TransportAuthenticator {
return NewTLS(&tls.Config{ServerName: serverName, RootCAs: cp})
}
// NewClientTLSFromFile constructs a TLS from the input certificate file for client.
func NewClientTLSFromFile(certFile, serverName string) (TransportAuthenticator, 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: serverName, RootCAs: cp}), nil
}
// NewServerTLSFromCert constructs a TLS from the input certificate for server.
func NewServerTLSFromCert(cert *tls.Certificate) TransportAuthenticator {
return NewTLS(&tls.Config{Certificates: []tls.Certificate{*cert}})
}
// NewServerTLSFromFile constructs a TLS from the input certificate file and key
// file for server.
func NewServerTLSFromFile(certFile, keyFile string) (TransportAuthenticator, error) {
cert, err := tls.LoadX509KeyPair(certFile, keyFile)
if err != nil {
return nil, err
}
return NewTLS(&tls.Config{Certificates: []tls.Certificate{cert}}), nil
}