From 1e2c3e5a3c1463cb8c7ec92d74aa739587b6642f Mon Sep 17 00:00:00 2001
From: Jordan Whited <jordan@tailscale.com>
Date: Wed, 8 Feb 2023 10:42:07 -0800
Subject: [PATCH] tun: guard Device.Events() against chan writes

Signed-off-by: Jordan Whited <jordan@tailscale.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 tun/netstack/tun.go    | 2 +-
 tun/tun.go             | 2 +-
 tun/tun_darwin.go      | 2 +-
 tun/tun_freebsd.go     | 2 +-
 tun/tun_linux.go       | 2 +-
 tun/tun_openbsd.go     | 2 +-
 tun/tun_windows.go     | 2 +-
 tun/tuntest/tuntest.go | 8 ++++----
 8 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/tun/netstack/tun.go b/tun/netstack/tun.go
index 25486a6..37c879d 100644
--- a/tun/netstack/tun.go
+++ b/tun/netstack/tun.go
@@ -109,7 +109,7 @@ func (tun *netTun) File() *os.File {
 	return nil
 }
 
-func (tun *netTun) Events() chan tun.Event {
+func (tun *netTun) Events() <-chan tun.Event {
 	return tun.events
 }
 
diff --git a/tun/tun.go b/tun/tun.go
index 7b26af0..01051b9 100644
--- a/tun/tun.go
+++ b/tun/tun.go
@@ -24,6 +24,6 @@ type Device interface {
 	Flush() error                   // flush all previous writes to the device
 	MTU() (int, error)              // returns the MTU of the device
 	Name() (string, error)          // fetches and returns the current name
-	Events() chan Event             // returns a constant channel of events related to the device
+	Events() <-chan Event           // returns a constant channel of events related to the device
 	Close() error                   // stops the device and closes the event channel
 }
diff --git a/tun/tun_darwin.go b/tun/tun_darwin.go
index a04bad4..7411a69 100644
--- a/tun/tun_darwin.go
+++ b/tun/tun_darwin.go
@@ -213,7 +213,7 @@ func (tun *NativeTun) File() *os.File {
 	return tun.tunFile
 }
 
-func (tun *NativeTun) Events() chan Event {
+func (tun *NativeTun) Events() <-chan Event {
 	return tun.events
 }
 
diff --git a/tun/tun_freebsd.go b/tun/tun_freebsd.go
index a8ebb34..42431aa 100644
--- a/tun/tun_freebsd.go
+++ b/tun/tun_freebsd.go
@@ -329,7 +329,7 @@ func (tun *NativeTun) File() *os.File {
 	return tun.tunFile
 }
 
-func (tun *NativeTun) Events() chan Event {
+func (tun *NativeTun) Events() <-chan Event {
 	return tun.events
 }
 
diff --git a/tun/tun_linux.go b/tun/tun_linux.go
index 6275399..25dbc07 100644
--- a/tun/tun_linux.go
+++ b/tun/tun_linux.go
@@ -376,7 +376,7 @@ func (tun *NativeTun) Read(buf []byte, offset int) (n int, err error) {
 	return
 }
 
-func (tun *NativeTun) Events() chan Event {
+func (tun *NativeTun) Events() <-chan Event {
 	return tun.events
 }
 
diff --git a/tun/tun_openbsd.go b/tun/tun_openbsd.go
index ee8cf5a..e7fd79c 100644
--- a/tun/tun_openbsd.go
+++ b/tun/tun_openbsd.go
@@ -200,7 +200,7 @@ func (tun *NativeTun) File() *os.File {
 	return tun.tunFile
 }
 
-func (tun *NativeTun) Events() chan Event {
+func (tun *NativeTun) Events() <-chan Event {
 	return tun.events
 }
 
diff --git a/tun/tun_windows.go b/tun/tun_windows.go
index 751ad21..d5abb14 100644
--- a/tun/tun_windows.go
+++ b/tun/tun_windows.go
@@ -102,7 +102,7 @@ func (tun *NativeTun) File() *os.File {
 	return nil
 }
 
-func (tun *NativeTun) Events() chan Event {
+func (tun *NativeTun) Events() <-chan Event {
 	return tun.events
 }
 
diff --git a/tun/tuntest/tuntest.go b/tun/tuntest/tuntest.go
index 4e61df5..b143c76 100644
--- a/tun/tuntest/tuntest.go
+++ b/tun/tuntest/tuntest.go
@@ -138,10 +138,10 @@ func (t *chTun) Write(data []byte, offset int) (int, error) {
 
 const DefaultMTU = 1420
 
-func (t *chTun) Flush() error           { return nil }
-func (t *chTun) MTU() (int, error)      { return DefaultMTU, nil }
-func (t *chTun) Name() (string, error)  { return "loopbackTun1", nil }
-func (t *chTun) Events() chan tun.Event { return t.c.events }
+func (t *chTun) Flush() error             { return nil }
+func (t *chTun) MTU() (int, error)        { return DefaultMTU, nil }
+func (t *chTun) Name() (string, error)    { return "loopbackTun1", nil }
+func (t *chTun) Events() <-chan tun.Event { return t.c.events }
 func (t *chTun) Close() error {
 	t.Write(nil, -1)
 	return nil