From 633de52aee8b72c252d8fd030df14f9164c2e9f3 Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Mon, 1 Feb 2021 20:06:45 +0800
Subject: [PATCH] Fix: wrap net.Conn to avoid using *net.TCPConn.(ReadFrom)
 (#1209)

---
 common/net/io.go     | 11 +++++++++++
 tunnel/connection.go |  7 +++++--
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 common/net/io.go

diff --git a/common/net/io.go b/common/net/io.go
new file mode 100644
index 00000000..5bb4f002
--- /dev/null
+++ b/common/net/io.go
@@ -0,0 +1,11 @@
+package net
+
+import "io"
+
+type ReadOnlyReader struct {
+	io.Reader
+}
+
+type WriteOnlyWriter struct {
+	io.Writer
+}
diff --git a/tunnel/connection.go b/tunnel/connection.go
index 77671a4b..b3554a47 100644
--- a/tunnel/connection.go
+++ b/tunnel/connection.go
@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/Dreamacro/clash/adapters/inbound"
+	N "github.com/Dreamacro/clash/common/net"
 	"github.com/Dreamacro/clash/common/pool"
 	"github.com/Dreamacro/clash/component/resolver"
 	C "github.com/Dreamacro/clash/constant"
@@ -141,14 +142,16 @@ func relay(leftConn, rightConn net.Conn) {
 
 	go func() {
 		buf := pool.Get(pool.RelayBufferSize)
-		_, err := io.CopyBuffer(leftConn, rightConn, buf)
+		// Wrapping to avoid using *net.TCPConn.(ReadFrom)
+		// See also https://github.com/Dreamacro/clash/pull/1209
+		_, err := io.CopyBuffer(N.WriteOnlyWriter{Writer: leftConn}, N.ReadOnlyReader{Reader: rightConn}, buf)
 		pool.Put(buf)
 		leftConn.SetReadDeadline(time.Now())
 		ch <- err
 	}()
 
 	buf := pool.Get(pool.RelayBufferSize)
-	io.CopyBuffer(rightConn, leftConn, buf)
+	io.CopyBuffer(N.WriteOnlyWriter{Writer: rightConn}, N.ReadOnlyReader{Reader: leftConn}, buf)
 	pool.Put(buf)
 	rightConn.SetReadDeadline(time.Now())
 	<-ch