From 9ea10763e47c195802d1f5a5c653cacaf6c1890f Mon Sep 17 00:00:00 2001
From: ginuerzh <ginuerzh@gmail.com>
Date: Sun, 21 Jun 2026 16:47:12 +0800
Subject: [PATCH] fix(listener): add panic recovery in TUN/TAP listenLoop for
 wintun crashes

On Windows, wintun.dll may pass an invalid pointer to the logMessage
callback, causing a nil pointer dereference in UTF16PtrToString that
panics the entire process. The upstream wintun-go library has not fixed
this since 2021.

Add defer/recover in tun/tungo/tap listenLoop inner closures to convert
panics from createTun/createTap into logged errors, allowing the retry
loop to recover gracefully instead of crashing the process.

Fixes go-gost/gost#482
---
 listener/tap/listener.go   | 9 ++++++++-
 listener/tun/listener.go   | 9 ++++++++-
 listener/tungo/listener.go | 9 ++++++++-
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/listener/tap/listener.go b/listener/tap/listener.go
index e86ff31f..3b868a2f 100644
--- a/listener/tap/listener.go
+++ b/listener/tap/listener.go
@@ -2,6 +2,7 @@ package tap
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"time"
 
@@ -68,7 +69,13 @@ func (l *tapListener) Init(md mdata.Metadata) (err error) {
 func (l *tapListener) listenLoop() {
 	for {
 		ctx, cancel := context.WithCancel(context.Background())
-		err := func() error {
+		err := func() (err error) {
+			defer func() {
+				if r := recover(); r != nil {
+					err = fmt.Errorf("panic in createTap: %v", r)
+				}
+			}()
+
 			ifce, name, ip, err := l.createTap()
 			if err != nil {
 				if ifce != nil {
diff --git a/listener/tun/listener.go b/listener/tun/listener.go
index 551a339e..a94a0451 100644
--- a/listener/tun/listener.go
+++ b/listener/tun/listener.go
@@ -2,6 +2,7 @@ package tun
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"time"
 
@@ -75,7 +76,13 @@ func (l *tunListener) Init(md mdata.Metadata) (err error) {
 func (l *tunListener) listenLoop(ready context.CancelCauseFunc) {
 	for {
 		ctx, cancel := context.WithCancel(context.Background())
-		err := func() error {
+		err := func() (err error) {
+			defer func() {
+				if r := recover(); r != nil {
+					err = fmt.Errorf("panic in createTun: %v", r)
+				}
+			}()
+
 			ifce, name, ip, err := l.createTun()
 			if err != nil {
 				if ifce != nil {
diff --git a/listener/tungo/listener.go b/listener/tungo/listener.go
index 548e8ff6..fac92098 100644
--- a/listener/tungo/listener.go
+++ b/listener/tungo/listener.go
@@ -2,6 +2,7 @@ package tungo
 
 import (
 	"context"
+	"fmt"
 	"net"
 	"time"
 
@@ -68,7 +69,13 @@ func (l *tunListener) Init(md mdata.Metadata) (err error) {
 func (l *tunListener) listenLoop(ready context.CancelCauseFunc) {
 	for {
 		ctx, cancel := context.WithCancel(context.Background())
-		err := func() error {
+		err := func() (err error) {
+			defer func() {
+				if r := recover(); r != nil {
+					err = fmt.Errorf("panic in createTun: %v", r)
+				}
+			}()
+
 			ifce, name, ip, err := l.createTun()
 			if err != nil {
 				if ifce != nil {