Clarify comment about switchToDirectCopy flag remaining true

Co-authored-by: RPRX <63339210+RPRX@users.noreply.github.com>

go.mod

@@ -25,6 +25,7 @@ require (
 	golang.org/x/net v0.48.0
 	golang.org/x/sync v0.19.0
 	golang.org/x/sys v0.39.0
+	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2
 	golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173
 	google.golang.org/grpc v1.78.0
 	google.golang.org/protobuf v1.36.11
@@ -50,7 +51,6 @@ require (
 	golang.org/x/text v0.32.0 // indirect
 	golang.org/x/time v0.12.0 // indirect
 	golang.org/x/tools v0.39.0 // indirect
-	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20251029180050-ab9386a59fda // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

proxy/proxy.go

@@ -224,7 +224,8 @@ func (w *VisionReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
 		switchToDirectCopy = &w.trafficState.Outbound.DownlinkReaderDirectCopy
 	}
 
-	if *switchToDirectCopy {
+	if *switchToDirectCopy && w.input == nil {
+		// Already switched to direct copy mode
 		if w.directReadCounter != nil {
 			w.directReadCounter.Add(int64(buffer.Len()))
 		}
@@ -257,11 +258,18 @@ func (w *VisionReader) ReadMultiBuffer() (buf.MultiBuffer, error) {
 
 	if *switchToDirectCopy {
 		// XTLS Vision processes TLS-like conn's input and rawInput
+		// input contains decrypted application data - safe to merge
 		if inputBuffer, err := buf.ReadFrom(w.input); err == nil && !inputBuffer.IsEmpty() {
 			buffer, _ = buf.MergeMulti(buffer, inputBuffer)
 		}
-		if rawInputBuffer, err := buf.ReadFrom(w.rawInput); err == nil && !rawInputBuffer.IsEmpty() {
-			buffer, _ = buf.MergeMulti(buffer, rawInputBuffer)
+		// rawInput may contain encrypted bytes for the next TLS record
+		// If rawInput is not empty, we should NOT switch to direct mode yet
+		// because those bytes need to be processed by the TLS layer first
+		if w.rawInput != nil && w.rawInput.Len() > 0 {
+			// rawInput has pending data - defer direct copy to next read
+			// *switchToDirectCopy remains true (unchanged), so we will retry on the next ReadMultiBuffer call
+			// This ensures we don't mix encrypted bytes with application data
+			return buffer, err
 		}
 		*w.input = bytes.Reader{} // release memory
 		w.input = nil

transport/internet/tls/config.go

@@ -290,10 +290,8 @@ func (r *RandCarrier) verifyPeerCert(rawCerts [][]byte, verifiedChains [][]*x509
 	// directly return success if pinned cert is leaf
 	// or add the CA to RootCAs if pinned cert is CA(and can be used in VerifyPeerCertInNames for Self signed CA)
 	RootCAs := r.RootCAs
-	var verifyResult verifyResult
-	var verifiedCert *x509.Certificate
 	if r.PinnedPeerCertSha256 != nil {
-		verifyResult, verifiedCert = verifyChain(certs, r.PinnedPeerCertSha256)
+		verifyResult, verifiedCert := verifyChain(certs, r.PinnedPeerCertSha256)
 		switch verifyResult {
 		case certNotFound:
 			return errors.New("peer cert is unrecognized")
@@ -307,39 +305,27 @@ func (r *RandCarrier) verifyPeerCert(rawCerts [][]byte, verifiedChains [][]*x509
 		}
 	}
 
-	if len(r.VerifyPeerCertInNames) > 0 {
-		opts := x509.VerifyOptions{
-			Roots:         RootCAs,
-			CurrentTime:   time.Now(),
-			Intermediates: x509.NewCertPool(),
-		}
-		for _, cert := range certs[1:] {
-			opts.Intermediates.AddCert(cert)
-		}
-		for _, opts.DNSName = range r.VerifyPeerCertInNames {
-			if _, err := certs[0].Verify(opts); err == nil {
-				return nil
+	if r.VerifyPeerCertInNames != nil {
+		if len(r.VerifyPeerCertInNames) > 0 {
+			opts := x509.VerifyOptions{
+				Roots:         RootCAs,
+				CurrentTime:   time.Now(),
+				Intermediates: x509.NewCertPool(),
+			}
+			for _, cert := range certs[1:] {
+				opts.Intermediates.AddCert(cert)
+			}
+			for _, opts.DNSName = range r.VerifyPeerCertInNames {
+				if _, err := certs[0].Verify(opts); err == nil {
+					return nil
+				}
 			}
-		}
-	} else if len(verifiedChains) == 0 && verifyResult == foundCA { // if found ca and verifiedChains is empty, we need to verify here
-		opts := x509.VerifyOptions{
-			Roots:         RootCAs,
-			CurrentTime:   time.Now(),
-			Intermediates: x509.NewCertPool(),
-			DNSName:       r.Config.ServerName,
-		}
-		for _, cert := range certs[1:] {
-			opts.Intermediates.AddCert(cert)
-		}
-		if _, err := certs[0].Verify(opts); err == nil {
-			return nil
 		}
 	}
 	return nil
 }
 
 type RandCarrier struct {
-	Config                *tls.Config
 	RootCAs               *x509.CertPool
 	VerifyPeerCertInNames []string
 	PinnedPeerCertSha256  [][]byte
@@ -380,7 +366,6 @@ func (c *Config) GetTLSConfig(opts ...Option) *tls.Config {
 		SessionTicketsDisabled: !c.EnableSessionResumption,
 		VerifyPeerCertificate:  randCarrier.verifyPeerCert,
 	}
-	randCarrier.Config = config
 	if len(c.VerifyPeerCertInNames) > 0 {
 		config.InsecureSkipVerify = true
 	} else {