noise: implement an API to send and receive early data

p2p/security/noise/crypto_test.go

@@ -93,7 +93,7 @@ func TestCryptoFailsIfHandshakeIncomplete(t *testing.T) {
 	init, resp := net.Pipe()
 	_ = resp.Close()
 
-	session, _ := newSecureSession(initTransport, context.TODO(), init, "remote-peer", nil, true)
+	session, _ := newSecureSession(initTransport, context.TODO(), init, "remote-peer", nil, nil, true)
 	_, err := session.encrypt(nil, []byte("hi"))
 	if err == nil {
 		t.Error("expected encryption error when handshake incomplete")

p2p/security/noise/handshake.go

@@ -10,17 +10,16 @@ import (
 	"runtime/debug"
 	"time"
 
-	"github.com/minio/sha256-simd"
 	"golang.org/x/crypto/chacha20poly1305"
 
-	"github.com/libp2p/go-libp2p/p2p/security/noise/pb"
-
 	"github.com/libp2p/go-libp2p/core/crypto"
 	"github.com/libp2p/go-libp2p/core/peer"
+	"github.com/libp2p/go-libp2p/p2p/security/noise/pb"
 
 	"github.com/flynn/noise"
 	"github.com/gogo/protobuf/proto"
 	pool "github.com/libp2p/go-buffer-pool"
+	"github.com/minio/sha256-simd"
 )
 
 // payloadSigPrefix is prepended to our Noise static key before signing with
@@ -89,10 +88,12 @@ func (s *secureSession) runHandshake(ctx context.Context) (err error) {
 
 	if s.initiator {
 		// stage 0 //
-		// do not send the payload just yet, as it would be plaintext; not secret.
 		// Handshake Msg Len = len(DH ephemeral key)
-		err = s.sendHandshakeMessage(hs, nil, hbuf)
-		if err != nil {
+		var ed []byte
+		if s.earlyDataHandler != nil {
+			ed = s.earlyDataHandler.Send(ctx, s.insecureConn, s.remoteID)
+		}
+		if err := s.sendHandshakeMessage(hs, ed, hbuf); err != nil {
 			return fmt.Errorf("error sending handshake message: %w", err)
 		}
 
@@ -101,29 +102,34 @@ func (s *secureSession) runHandshake(ctx context.Context) (err error) {
 		if err != nil {
 			return fmt.Errorf("error reading handshake message: %w", err)
 		}
-		err = s.handleRemoteHandshakePayload(plaintext, hs.PeerStatic())
-		if err != nil {
+		if err := s.handleRemoteHandshakePayload(plaintext, hs.PeerStatic()); err != nil {
 			return err
 		}
 
 		// stage 2 //
 		// Handshake Msg Len = len(DHT static key) +  MAC(static key is encrypted) + len(Payload) + MAC(payload is encrypted)
-		err = s.sendHandshakeMessage(hs, payload, hbuf)
-		if err != nil {
+		if err := s.sendHandshakeMessage(hs, payload, hbuf); err != nil {
 			return fmt.Errorf("error sending handshake message: %w", err)
 		}
+		return nil
 	} else {
 		// stage 0 //
-		// We don't expect any payload on the first message.
-		if _, err := s.readHandshakeMessage(hs); err != nil {
+		initialPayload, err := s.readHandshakeMessage(hs)
+		if err != nil {
 			return fmt.Errorf("error reading handshake message: %w", err)
 		}
+		if s.earlyDataHandler != nil {
+			if err := s.earlyDataHandler.Received(ctx, s.insecureConn, initialPayload); err != nil {
+				return err
+			}
+		} else if len(initialPayload) > 0 {
+			return fmt.Errorf("received unexpected early data (%d bytes)", len(initialPayload))
+		}
 
 		// stage 1 //
 		// Handshake Msg Len = len(DH ephemeral key) + len(DHT static key) +  MAC(static key is encrypted) + len(Payload) +
 		// MAC(payload is encrypted)
-		err = s.sendHandshakeMessage(hs, payload, hbuf)
-		if err != nil {
+		if err := s.sendHandshakeMessage(hs, payload, hbuf); err != nil {
 			return fmt.Errorf("error sending handshake message: %w", err)
 		}
 
@@ -132,13 +138,8 @@ func (s *secureSession) runHandshake(ctx context.Context) (err error) {
 		if err != nil {
 			return fmt.Errorf("error reading handshake message: %w", err)
 		}
-		err = s.handleRemoteHandshakePayload(plaintext, hs.PeerStatic())
-		if err != nil {
-			return err
-		}
+		return s.handleRemoteHandshakePayload(plaintext, hs.PeerStatic())
 	}
-
-	return nil
 }
 
 // setCipherStates sets the initial cipher states that will be used to protect

p2p/security/noise/session.go

@@ -36,20 +36,22 @@ type secureSession struct {
 	dec *noise.CipherState
 
 	// noise prologue
-	prologue []byte
+	prologue         []byte
+	earlyDataHandler EarlyDataHandler
 }
 
 // newSecureSession creates a Noise session over the given insecureConn Conn, using
 // the libp2p identity keypair from the given Transport.
-func newSecureSession(tpt *Transport, ctx context.Context, insecure net.Conn, remote peer.ID, prologue []byte, initiator bool) (*secureSession, error) {
+func newSecureSession(tpt *Transport, ctx context.Context, insecure net.Conn, remote peer.ID, prologue []byte, edh EarlyDataHandler, initiator bool) (*secureSession, error) {
 	s := &secureSession{
-		insecureConn:   insecure,
-		insecureReader: bufio.NewReader(insecure),
-		initiator:      initiator,
-		localID:        tpt.localID,
-		localKey:       tpt.privateKey,
-		remoteID:       remote,
-		prologue:       prologue,
+		insecureConn:     insecure,
+		insecureReader:   bufio.NewReader(insecure),
+		initiator:        initiator,
+		localID:          tpt.localID,
+		localKey:         tpt.privateKey,
+		remoteID:         remote,
+		prologue:         prologue,
+		earlyDataHandler: edh,
 	}
 
 	// the go-routine we create to run the handshake will

p2p/security/noise/session_transport.go

@@ -22,6 +22,22 @@ func Prologue(prologue []byte) SessionOption {
 	}
 }
 
+// EarlyDataHandler allows attaching an (unencrypted) application payload to the first handshake message.
+// While unencrypted, the integrity of this early data is retroactively authenticated on completion of the handshake.
+type EarlyDataHandler interface {
+	// Send is called for the client before sending the first handshake message.
+	Send(context.Context, net.Conn, peer.ID) []byte
+	// Received is called for the server when the first handshake message from the client is received.
+	Received(context.Context, net.Conn, []byte) error
+}
+
+func EarlyData(h EarlyDataHandler) SessionOption {
+	return func(s *SessionTransport) error {
+		s.earlyDataHandler = h
+		return nil
+	}
+}
+
 var _ sec.SecureTransport = &SessionTransport{}
 
 // SessionTransport can be used
@@ -29,13 +45,14 @@ var _ sec.SecureTransport = &SessionTransport{}
 type SessionTransport struct {
 	t *Transport
 	// options
-	prologue []byte
+	prologue         []byte
+	earlyDataHandler EarlyDataHandler
 }
 
 // SecureInbound runs the Noise handshake as the responder.
 // If p is empty, connections from any peer are accepted.
 func (i *SessionTransport) SecureInbound(ctx context.Context, insecure net.Conn, p peer.ID) (sec.SecureConn, error) {
-	c, err := newSecureSession(i.t, ctx, insecure, p, i.prologue, false)
+	c, err := newSecureSession(i.t, ctx, insecure, p, i.prologue, i.earlyDataHandler, false)
 	if err != nil {
 		addr, maErr := manet.FromNetAddr(insecure.RemoteAddr())
 		if maErr == nil {
@@ -47,5 +64,5 @@ func (i *SessionTransport) SecureInbound(ctx context.Context, insecure net.Conn,
 
 // SecureOutbound runs the Noise handshake as the initiator.
 func (i *SessionTransport) SecureOutbound(ctx context.Context, insecure net.Conn, p peer.ID) (sec.SecureConn, error) {
-	return newSecureSession(i.t, ctx, insecure, p, i.prologue, true)
+	return newSecureSession(i.t, ctx, insecure, p, i.prologue, i.earlyDataHandler, true)
 }

p2p/security/noise/transport.go

@@ -41,7 +41,7 @@ func New(privkey crypto.PrivKey) (*Transport, error) {
 // SecureInbound runs the Noise handshake as the responder.
 // If p is empty, connections from any peer are accepted.
 func (t *Transport) SecureInbound(ctx context.Context, insecure net.Conn, p peer.ID) (sec.SecureConn, error) {
-	c, err := newSecureSession(t, ctx, insecure, p, nil, false)
+	c, err := newSecureSession(t, ctx, insecure, p, nil, nil, false)
 	if err != nil {
 		addr, maErr := manet.FromNetAddr(insecure.RemoteAddr())
 		if maErr == nil {
@@ -53,7 +53,7 @@ func (t *Transport) SecureInbound(ctx context.Context, insecure net.Conn, p peer
 
 // SecureOutbound runs the Noise handshake as the initiator.
 func (t *Transport) SecureOutbound(ctx context.Context, insecure net.Conn, p peer.ID) (sec.SecureConn, error) {
-	return newSecureSession(t, ctx, insecure, p, nil, true)
+	return newSecureSession(t, ctx, insecure, p, nil, nil, true)
 }
 
 func (t *Transport) WithSessionOptions(opts ...SessionOption) (sec.SecureTransport, error) {

p2p/security/noise/transport_test.go

@@ -78,10 +78,10 @@ func connect(t *testing.T, initTransport, respTransport *Transport) (*secureSess
 	done := make(chan struct{})
 	go func() {
 		defer close(done)
-		initConn, initErr = initTransport.SecureOutbound(context.TODO(), init, respTransport.localID)
+		initConn, initErr = initTransport.SecureOutbound(context.Background(), init, respTransport.localID)
 	}()
 
-	respConn, respErr := respTransport.SecureInbound(context.TODO(), resp, "")
+	respConn, respErr := respTransport.SecureInbound(context.Background(), resp, "")
 	<-done
 
 	if initErr != nil {
@@ -171,7 +171,7 @@ func TestPeerIDMatch(t *testing.T) {
 	done := make(chan struct{})
 	go func() {
 		defer close(done)
-		conn, err := initTransport.SecureOutbound(context.TODO(), init, respTransport.localID)
+		conn, err := initTransport.SecureOutbound(context.Background(), init, respTransport.localID)
 		assert.NoError(t, err)
 		assert.Equal(t, conn.RemotePeer(), respTransport.localID)
 		b := make([]byte, 6)
@@ -180,7 +180,7 @@ func TestPeerIDMatch(t *testing.T) {
 		assert.Equal(t, b, []byte("foobar"))
 	}()
 
-	conn, err := respTransport.SecureInbound(context.TODO(), resp, initTransport.localID)
+	conn, err := respTransport.SecureInbound(context.Background(), resp, initTransport.localID)
 	require.NoError(t, err)
 	require.Equal(t, conn.RemotePeer(), initTransport.localID)
 	_, err = conn.Write([]byte("foobar"))
@@ -194,11 +194,11 @@ func TestPeerIDMismatchOutboundFailsHandshake(t *testing.T) {
 
 	errChan := make(chan error)
 	go func() {
-		_, err := initTransport.SecureOutbound(context.TODO(), init, "a-random-peer-id")
+		_, err := initTransport.SecureOutbound(context.Background(), init, "a-random-peer-id")
 		errChan <- err
 	}()
 
-	_, err := respTransport.SecureInbound(context.TODO(), resp, "")
+	_, err := respTransport.SecureInbound(context.Background(), resp, "")
 	require.Error(t, err)
 
 	initErr := <-errChan
@@ -214,13 +214,13 @@ func TestPeerIDMismatchInboundFailsHandshake(t *testing.T) {
 	done := make(chan struct{})
 	go func() {
 		defer close(done)
-		conn, err := initTransport.SecureOutbound(context.TODO(), init, respTransport.localID)
+		conn, err := initTransport.SecureOutbound(context.Background(), init, respTransport.localID)
 		assert.NoError(t, err)
 		_, err = conn.Read([]byte{0})
 		assert.Error(t, err)
 	}()
 
-	_, err := respTransport.SecureInbound(context.TODO(), resp, "a-random-peer-id")
+	_, err := respTransport.SecureInbound(context.Background(), resp, "a-random-peer-id")
 	require.Error(t, err, "expected responder to fail with peer ID mismatch error")
 	<-done
 }
@@ -387,7 +387,7 @@ func TestPrologueMatches(t *testing.T) {
 		tpt, err := initTransport.
 			WithSessionOptions(Prologue(commonPrologue))
 		require.NoError(t, err)
-		conn, err := tpt.SecureOutbound(context.TODO(), initConn, respTransport.localID)
+		conn, err := tpt.SecureOutbound(context.Background(), initConn, respTransport.localID)
 		require.NoError(t, err)
 		defer conn.Close()
 	}()
@@ -395,7 +395,7 @@ func TestPrologueMatches(t *testing.T) {
 	tpt, err := respTransport.
 		WithSessionOptions(Prologue(commonPrologue))
 	require.NoError(t, err)
-	conn, err := tpt.SecureInbound(context.TODO(), respConn, "")
+	conn, err := tpt.SecureInbound(context.Background(), respConn, "")
 	require.NoError(t, err)
 	defer conn.Close()
 	<-done
@@ -415,14 +415,125 @@ func TestPrologueDoesNotMatchFailsHandshake(t *testing.T) {
 		tpt, err := initTransport.
 			WithSessionOptions(Prologue(initPrologue))
 		require.NoError(t, err)
-		_, err = tpt.SecureOutbound(context.TODO(), initConn, respTransport.localID)
+		_, err = tpt.SecureOutbound(context.Background(), initConn, respTransport.localID)
 		require.Error(t, err)
 	}()
 
 	tpt, err := respTransport.WithSessionOptions(Prologue(respPrologue))
 	require.NoError(t, err)
 
-	_, err = tpt.SecureInbound(context.TODO(), respConn, "")
+	_, err = tpt.SecureInbound(context.Background(), respConn, "")
 	require.Error(t, err)
 	<-done
 }
+
+type earlyDataHandler struct {
+	send     func(context.Context, net.Conn, peer.ID) []byte
+	received func(context.Context, net.Conn, []byte) error
+}
+
+func (e *earlyDataHandler) Send(ctx context.Context, conn net.Conn, id peer.ID) []byte {
+	if e.send == nil {
+		return nil
+	}
+	return e.send(ctx, conn, id)
+}
+
+func (e *earlyDataHandler) Received(ctx context.Context, conn net.Conn, data []byte) error {
+	if e.received == nil {
+		return nil
+	}
+	return e.received(ctx, conn, data)
+}
+
+func TestEarlyDataAccepted(t *testing.T) {
+	var receivedEarlyData []byte
+	serverEDH := &earlyDataHandler{
+		received: func(_ context.Context, _ net.Conn, data []byte) error {
+			receivedEarlyData = data
+			return nil
+		},
+	}
+	clientEDH := &earlyDataHandler{
+		send: func(ctx context.Context, conn net.Conn, id peer.ID) []byte { return []byte("foobar") },
+	}
+	initTransport, err := newTestTransport(t, crypto.Ed25519, 2048).WithSessionOptions(EarlyData(clientEDH))
+	require.NoError(t, err)
+	tpt := newTestTransport(t, crypto.Ed25519, 2048)
+	respTransport, err := tpt.WithSessionOptions(EarlyData(serverEDH))
+	require.NoError(t, err)
+
+	initConn, respConn := newConnPair(t)
+
+	errChan := make(chan error)
+	go func() {
+		_, err := respTransport.SecureInbound(context.Background(), initConn, "")
+		errChan <- err
+	}()
+
+	conn, err := initTransport.SecureOutbound(context.Background(), respConn, tpt.localID)
+	require.NoError(t, err)
+	defer conn.Close()
+
+	require.Equal(t, []byte("foobar"), receivedEarlyData)
+}
+
+func TestEarlyDataRejected(t *testing.T) {
+	serverEDH := &earlyDataHandler{
+		received: func(_ context.Context, _ net.Conn, data []byte) error { return errors.New("nope") },
+	}
+	clientEDH := &earlyDataHandler{
+		send: func(ctx context.Context, conn net.Conn, id peer.ID) []byte { return []byte("foobar") },
+	}
+	initTransport, err := newTestTransport(t, crypto.Ed25519, 2048).WithSessionOptions(EarlyData(clientEDH))
+	require.NoError(t, err)
+	tpt := newTestTransport(t, crypto.Ed25519, 2048)
+	respTransport, err := tpt.WithSessionOptions(EarlyData(serverEDH))
+	require.NoError(t, err)
+
+	initConn, respConn := newConnPair(t)
+
+	errChan := make(chan error)
+	go func() {
+		_, err := respTransport.SecureInbound(context.Background(), initConn, "")
+		errChan <- err
+	}()
+
+	_, err = initTransport.SecureOutbound(context.Background(), respConn, tpt.localID)
+	require.Error(t, err)
+
+	select {
+	case <-time.After(500 * time.Millisecond):
+		t.Fatal("timeout")
+	case err := <-errChan:
+		require.EqualError(t, err, "nope")
+	}
+}
+
+func TestEarlyDataRejectedWithNoHandler(t *testing.T) {
+	clientEDH := &earlyDataHandler{
+		send: func(ctx context.Context, conn net.Conn, id peer.ID) []byte { return []byte("foobar") },
+	}
+	initTransport, err := newTestTransport(t, crypto.Ed25519, 2048).WithSessionOptions(EarlyData(clientEDH))
+	require.NoError(t, err)
+	respTransport := newTestTransport(t, crypto.Ed25519, 2048)
+
+	initConn, respConn := newConnPair(t)
+
+	errChan := make(chan error)
+	go func() {
+		_, err := respTransport.SecureInbound(context.Background(), initConn, "")
+		errChan <- err
+	}()
+
+	_, err = initTransport.SecureOutbound(context.Background(), respConn, respTransport.localID)
+	require.Error(t, err)
+
+	select {
+	case <-time.After(500 * time.Millisecond):
+		t.Fatal("timeout")
+	case err := <-errChan:
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "received unexpected early data")
+	}
+}