return the local TLS error, but don't send it on the wire

integrationtests/self/handshake_test.go

@@ -138,8 +138,7 @@ var _ = Describe("Handshake tests", func() {
 						tlsConf,
 						clientConfig,
 					)
-					// TODO: check the error returned locally here
-					Expect(err).To(HaveOccurred())
+					Expect(err).To(MatchError("CRYPTO_ERROR: x509: cannot validate certificate for 127.0.0.1 because it doesn't contain any IP SANs"))
 				})
 
 				It("fails the handshake if the client fails to provide the requested client cert", func() {

internal/handshake/crypto_setup.go

@@ -65,7 +65,7 @@ type cryptoSetup struct {
 
 	handleParamsCallback func([]byte)
 
-	alertChan chan error
+	alertChan chan uint8
 	// HandleData() sends errors on the messageErrChan
 	messageErrChan chan error
 	// handshakeDone is closed as soon as the go routine running qtls.Handshake() returns
@@ -187,7 +187,7 @@ func newCryptoSetup(
 		logger:                 logger,
 		perspective:            perspective,
 		handshakeDone:          make(chan struct{}),
-		alertChan:              make(chan error),
+		alertChan:              make(chan uint8),
 		messageErrChan:         make(chan error, 1),
 		clientHelloWrittenChan: make(chan struct{}),
 		messageChan:            make(chan []byte, 100),
@@ -213,10 +213,11 @@ func (h *cryptoSetup) ChangeConnectionID(id protocol.ConnectionID) error {
 func (h *cryptoSetup) RunHandshake() error {
 	// Handle errors that might occur when HandleData() is called.
 	handshakeComplete := make(chan struct{})
+	handshakeErrChan := make(chan error, 1)
 	go func() {
 		defer close(h.handshakeDone)
 		if err := h.conn.Handshake(); err != nil {
-			h.logger.Debugf("qlts.Handshake error: %s", err)
+			handshakeErrChan <- err
 			return
 		}
 		close(handshakeComplete)
@@ -229,9 +230,9 @@ func (h *cryptoSetup) RunHandshake() error {
 		return errors.New("Handshake aborted")
 	case <-handshakeComplete: // return when the handshake is done
 		return nil
-	case err := <-h.alertChan:
-		<-h.handshakeDone
-		return err
+	case alert := <-h.alertChan:
+		err := <-handshakeErrChan
+		return qerr.CryptoError(alert, err.Error())
 	case err := <-h.messageErrChan:
 		// If the handshake errored because of an error that occurred during HandleData(),
 		// that error message will be more useful than the error message generated by Handshake().
@@ -462,7 +463,7 @@ func (h *cryptoSetup) WriteRecord(p []byte) (int, error) {
 }
 
 func (h *cryptoSetup) SendAlert(alert uint8) {
-	h.alertChan <- qerr.CryptoError(alert, "")
+	h.alertChan <- alert
 }
 
 func (h *cryptoSetup) GetSealer() (protocol.EncryptionLevel, Sealer) {

internal/handshake/crypto_setup_test.go

@@ -128,7 +128,7 @@ var _ = Describe("Crypto Setup TLS", func() {
 		go func() {
 			defer GinkgoRecover()
 			err := server.RunHandshake()
-			Expect(err).To(MatchError("CRYPTO_ERROR: tls: unexpected message"))
+			Expect(err).To(MatchError("CRYPTO_ERROR: local error: tls: unexpected message"))
 			close(done)
 		}()
 

internal/qerr/quic_error.go

@@ -45,6 +45,11 @@ func (e *QuicError) Error() string {
 	return fmt.Sprintf("%s: %s", e.ErrorCode.String(), e.ErrorMessage)
 }
 
+// IsCryptoError says if this error is a crypto error
+func (e *QuicError) IsCryptoError() bool {
+	return e.ErrorCode.isCryptoError()
+}
+
 // Temporary says if the error is temporary.
 func (e *QuicError) Temporary() bool {
 	return false

internal/qerr/quic_error_test.go

@@ -25,6 +25,7 @@ var _ = Describe("QUIC Transport Errors", func() {
 		Expect(err.Error()).To(Equal("NO_ERROR: foobar"))
 	})
 
+	Context("crypto errors", func() {
 		It("has a string representation for crypto errors with a message", func() {
 			err := CryptoError(42, "foobar")
 			Expect(err.Error()).To(Equal("CRYPTO_ERROR: foobar"))
@@ -35,6 +36,12 @@ var _ = Describe("QUIC Transport Errors", func() {
 			Expect(err.Error()).To(Equal("CRYPTO_ERROR: tls: bad certificate"))
 		})
 
+		It("says if an error is a crypto error", func() {
+			Expect(Error(FlowControlError, "").IsCryptoError()).To(BeFalse())
+			Expect(CryptoError(42, "").IsCryptoError()).To(BeTrue())
+		})
+	})
+
 	Context("ErrorCode", func() {
 		It("works as error", func() {
 			var err error = StreamStateError

session.go

@@ -1133,9 +1133,14 @@ func (s *session) sendPackedPacket(packet *packedPacket) error {
 }
 
 func (s *session) sendConnectionClose(quicErr *qerr.QuicError) error {
+	var reason string
+	// don't send details of crypto errors
+	if !quicErr.IsCryptoError() {
+		reason = quicErr.ErrorMessage
+	}
 	packet, err := s.packer.PackConnectionClose(&wire.ConnectionCloseFrame{
 		ErrorCode:    quicErr.ErrorCode,
-		ReasonPhrase: quicErr.ErrorMessage,
+		ReasonPhrase: reason,
 	})
 	if err != nil {
 		return err