Add VLESS server, vision flow and reality TLS

common/tls/reality_client.go

@@ -0,0 +1,187 @@
+//go:build with_utls
+
+package tls
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/ed25519"
+	"crypto/hmac"
+	"crypto/sha256"
+	"crypto/sha512"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+	"net"
+	"reflect"
+	"time"
+	"unsafe"
+
+	"github.com/sagernet/sing-box/adapter"
+	"github.com/sagernet/sing-box/option"
+	"github.com/sagernet/sing/common/debug"
+	E "github.com/sagernet/sing/common/exceptions"
+	utls "github.com/sagernet/utls"
+
+	"golang.org/x/crypto/hkdf"
+)
+
+var _ Config = (*RealityClientConfig)(nil)
+
+type RealityClientConfig struct {
+	uClient   *UTLSClientConfig
+	publicKey []byte
+	shortID   []byte
+}
+
+func NewRealityClient(router adapter.Router, serverAddress string, options option.OutboundTLSOptions) (*RealityClientConfig, error) {
+	if options.UTLS == nil || !options.UTLS.Enabled {
+		return nil, E.New("uTLS is required by reality client")
+	}
+
+	uClient, err := NewUTLSClient(router, serverAddress, options)
+	if err != nil {
+		return nil, err
+	}
+
+	publicKey, err := base64.RawURLEncoding.DecodeString(options.Reality.PublicKey)
+	if err != nil {
+		return nil, E.Cause(err, "decode public_key")
+	}
+	if len(publicKey) != 32 {
+		return nil, E.New("invalid public_key")
+	}
+	shortID, err := hex.DecodeString(options.Reality.ShortID)
+	if err != nil {
+		return nil, E.Cause(err, "decode short_id")
+	}
+	if len(shortID) != 8 {
+		return nil, E.New("invalid short_id")
+	}
+	return &RealityClientConfig{uClient, publicKey, shortID}, nil
+}
+
+func (e *RealityClientConfig) ServerName() string {
+	return e.uClient.ServerName()
+}
+
+func (e *RealityClientConfig) SetServerName(serverName string) {
+	e.uClient.SetServerName(serverName)
+}
+
+func (e *RealityClientConfig) NextProtos() []string {
+	return e.uClient.NextProtos()
+}
+
+func (e *RealityClientConfig) SetNextProtos(nextProto []string) {
+	e.uClient.SetNextProtos(nextProto)
+}
+
+func (e *RealityClientConfig) Config() (*STDConfig, error) {
+	return nil, E.New("unsupported usage for reality")
+}
+
+func (e *RealityClientConfig) Client(conn net.Conn) (Conn, error) {
+	verifier := &realityVerifier{
+		serverName: e.uClient.ServerName(),
+	}
+	uConfig := e.uClient.config.Clone()
+	uConfig.InsecureSkipVerify = true
+	uConfig.SessionTicketsDisabled = true
+	uConfig.VerifyPeerCertificate = verifier.VerifyPeerCertificate
+	uConn := utls.UClient(conn, uConfig, e.uClient.id)
+	verifier.UConn = uConn
+	err := uConn.BuildHandshakeState()
+	if err != nil {
+		return nil, err
+	}
+	hello := uConn.HandshakeState.Hello
+	hello.SessionId = make([]byte, 32)
+	copy(hello.Raw[39:], hello.SessionId)
+
+	var nowTime time.Time
+	if uConfig.Time != nil {
+		nowTime = uConfig.Time()
+	} else {
+		nowTime = time.Now()
+	}
+	binary.BigEndian.PutUint64(hello.SessionId, uint64(nowTime.Unix()))
+
+	hello.SessionId[0] = 1
+	hello.SessionId[1] = 7
+	hello.SessionId[2] = 5
+	copy(hello.SessionId[8:], e.shortID)
+
+	if debug.Enabled {
+		fmt.Printf("REALITY hello.sessionId[:16]: %v\n", hello.SessionId[:16])
+	}
+
+	authKey := uConn.HandshakeState.State13.EcdheParams.SharedKey(e.publicKey)
+	if authKey == nil {
+		return nil, E.New("nil auth_key")
+	}
+	verifier.authKey = authKey
+	_, err = hkdf.New(sha256.New, authKey, hello.Random[:20], []byte("REALITY")).Read(authKey)
+	if err != nil {
+		return nil, err
+	}
+	aesBlock, _ := aes.NewCipher(authKey)
+	aesGcmCipher, _ := cipher.NewGCM(aesBlock)
+	aesGcmCipher.Seal(hello.SessionId[:0], hello.Random[20:], hello.SessionId[:16], hello.Raw)
+	copy(hello.Raw[39:], hello.SessionId)
+	if debug.Enabled {
+		fmt.Printf("REALITY hello.sessionId: %v\n", hello.SessionId)
+		fmt.Printf("REALITY uConn.AuthKey: %v\n", authKey)
+	}
+
+	return &utlsConnWrapper{uConn}, nil
+}
+
+func (e *RealityClientConfig) SetSessionIDGenerator(generator func(clientHello []byte, sessionID []byte) error) {
+	e.uClient.config.SessionIDGenerator = generator
+}
+
+func (e *RealityClientConfig) Clone() Config {
+	return &RealityClientConfig{
+		e.uClient.Clone().(*UTLSClientConfig),
+		e.publicKey,
+		e.shortID,
+	}
+}
+
+type realityVerifier struct {
+	*utls.UConn
+	serverName string
+	authKey    []byte
+	verified   bool
+}
+
+func (c *realityVerifier) VerifyPeerCertificate(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error {
+	p, _ := reflect.TypeOf(c.Conn).Elem().FieldByName("peerCertificates")
+	certs := *(*([]*x509.Certificate))(unsafe.Pointer(uintptr(unsafe.Pointer(c.Conn)) + p.Offset))
+	if pub, ok := certs[0].PublicKey.(ed25519.PublicKey); ok {
+		h := hmac.New(sha512.New, c.authKey)
+		h.Write(pub)
+		if bytes.Equal(h.Sum(nil), certs[0].Signature) {
+			c.verified = true
+			return nil
+		}
+	}
+	opts := x509.VerifyOptions{
+		DNSName:       c.serverName,
+		Intermediates: x509.NewCertPool(),
+	}
+	for _, cert := range certs[1:] {
+		opts.Intermediates.AddCert(cert)
+	}
+	if _, err := certs[0].Verify(opts); err != nil {
+		return err
+	}
+	if !c.verified {
+		return E.New("reality verification failed")
+	}
+	return nil
+}