Move clienhello to faketls

mtglib/internal/faketls/clienthello.go

@@ -1,4 +1,4 @@
-package clienthello
+package faketls
 
 import (
 	"crypto/hmac"
@@ -16,10 +16,10 @@ type ClientHello struct {
 	SessionID []byte
 }
 
-func ParseHandshake(secret, handshake []byte) (ClientHello, error) {
+func ParseClientHello(secret, handshake []byte) (ClientHello, error) {
 	hello := ClientHello{}
 
-	if len(handshake) < MinLen {
+	if len(handshake) < ClientHelloMinLen {
 		return hello, fmt.Errorf("lengh of handshake is too small: %d", len(handshake))
 	}
 
@@ -27,9 +27,9 @@ func ParseHandshake(secret, handshake []byte) (ClientHello, error) {
 		return hello, fmt.Errorf("unknown handshake type %#x", handshake[0])
 	}
 
-	copy(hello.Digest[:], handshake[RandomOffset:])
+	copy(hello.Digest[:], handshake[ClientHelloRandomOffset:])
 
-	for i := RandomOffset; i < RandomOffset+RandomLen; i++ {
+	for i := ClientHelloRandomOffset; i < ClientHelloRandomOffset+RandomLen; i++ {
 		handshake[i] = 0
 	}
 
@@ -60,8 +60,8 @@ func ParseHandshake(secret, handshake []byte) (ClientHello, error) {
 	timestamp := int64(binary.LittleEndian.Uint32(computedDigest[RandomLen-4:]))
 	hello.Time = time.Unix(timestamp, 0)
 
-	hello.SessionID = make([]byte, handshake[SessionIDOffset])
+	hello.SessionID = make([]byte, handshake[ClientHelloSessionIDOffset])
-	copy(hello.SessionID, handshake[SessionIDOffset+1:])
+	copy(hello.SessionID, handshake[ClientHelloSessionIDOffset+1:])
 
 	return hello, nil
 }

mtglib/internal/faketls/clienthello/init.go

@@ -1,17 +0,0 @@
-package clienthello
-
-import "errors"
-
-const (
-	RandomLen       = 32
-	RandomOffset    = 6
-	SessionIDOffset = RandomOffset + RandomLen
-	MinLen          = SessionIDOffset + 1
-
-	HandshakeTypeClient = 0x01
-)
-
-var (
-	ErrBadDigest        = errors.New("bad digest")
-	ErrAntiReplayAttack = errors.New("antireplay attack was detected")
-)

mtglib/internal/faketls/init.go

@@ -0,0 +1,18 @@
+package faketls
+
+import "errors"
+
+const (
+	RandomLen = 32
+
+	ClientHelloRandomOffset    = 6
+	ClientHelloSessionIDOffset = ClientHelloRandomOffset + RandomLen
+	ClientHelloMinLen      = ClientHelloSessionIDOffset + 1
+
+	HandshakeTypeClient = 0x01
+)
+
+var (
+	ErrBadDigest        = errors.New("bad digest")
+	ErrAntiReplayAttack = errors.New("antireplay attack was detected")
+)

mtglib/proxy.go

@@ -8,7 +8,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/9seconds/mtg/v2/mtglib/internal/faketls/clienthello"
+	"github.com/9seconds/mtg/v2/mtglib/internal/faketls"
 	"github.com/9seconds/mtg/v2/mtglib/internal/faketls/record"
 	"github.com/9seconds/mtg/v2/mtglib/internal/obfuscated2"
 	"github.com/9seconds/mtg/v2/mtglib/internal/relay"
@@ -58,7 +58,7 @@ func (p *Proxy) ServeConn(conn net.Conn) {
 		ctx.logger.Info("Stream has been finished")
 	}()
 
-	if err := p.doFakeTLSHandshake(ctx); err != nil {
+	if err := p.doFakeTLSHandshake(ctx, ctx.clientConn); err != nil {
 		p.logger.InfoError("faketls handshake is failed", err)
 
 		return
@@ -121,17 +121,28 @@ func (p *Proxy) Shutdown() {
 	p.workerPool.Release()
 }
 
-func (p *Proxy) doFakeTLSHandshake(ctx *streamContext) error {
+func (p *Proxy) doFakeTLSHandshake(ctx *streamContext, conn net.Conn) error {
 	clientHelloRecord := record.AcquireRecord()
 	defer record.ReleaseRecord(clientHelloRecord)
 
-	if err := clientHelloRecord.Read(ctx.clientConn); err != nil {
+	if err := clientHelloRecord.Read(conn); err != nil {
 		return fmt.Errorf("cannot read client hello: %w", err)
 	}
 
-	hello, _ := clienthello.ParseHandshake(p.secret.Key[:],
+	hello, err := faketls.ParseClientHello(p.secret.Key[:],
 		clientHelloRecord.Payload.Bytes())
-	fmt.Println(hello)
+	if err != nil {
+		return fmt.Errorf("cannot parse client hello: %w", err)
+	}
+
+	if err := p.timeAttackDetector.Valid(hello.Time); err != nil {
+		return fmt.Errorf("invalid time: %w", err)
+	}
+	if p.antiReplayCache.SeenBefore(hello.SessionID) {
+		p.logger.Warning("anti replay attack was detected")
+
+		return fmt.Errorf("anti replay attack from %s", ctx.ClientIP().String())
+	}
 
 	return fmt.Errorf("SUCCESS")
 }