From 7f905f48812d8c26110804c9dbf4fd83f650fe8c Mon Sep 17 00:00:00 2001
From: evilsocket <evilsocket@gmail.com>
Date: Thu, 2 Aug 2018 17:03:11 +0200
Subject: [PATCH] fix: fixed a race condition while doing wifi channel hopping

---
 modules/wifi.go         | 2 ++
 modules/wifi_hopping.go | 7 ++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/modules/wifi.go b/modules/wifi.go
index 0c7ff512..b1360e13 100644
--- a/modules/wifi.go
+++ b/modules/wifi.go
@@ -36,6 +36,7 @@ type WiFiModule struct {
 	apConfig            packets.Dot11ApConfig
 	writes              *sync.WaitGroup
 	reads               *sync.WaitGroup
+	chanLock            *sync.Mutex
 }
 
 func NewWiFiModule(s *session.Session) *WiFiModule {
@@ -49,6 +50,7 @@ func NewWiFiModule(s *session.Session) *WiFiModule {
 		apRunning:     false,
 		writes:        &sync.WaitGroup{},
 		reads:         &sync.WaitGroup{},
+		chanLock:      &sync.Mutex{},
 	}
 
 	w.AddHandler(session.NewModuleHandler("wifi.recon on", "",
diff --git a/modules/wifi_hopping.go b/modules/wifi_hopping.go
index 558b590b..49bec764 100644
--- a/modules/wifi_hopping.go
+++ b/modules/wifi_hopping.go
@@ -8,6 +8,9 @@ import (
 )
 
 func (w *WiFiModule) onChannel(channel int, cb func()) {
+	w.chanLock.Lock()
+	defer w.chanLock.Unlock()
+
 	prev := w.stickChan
 	w.stickChan = channel
 
@@ -46,11 +49,13 @@ func (w *WiFiModule) channelHopper() {
 				channel = w.stickChan
 			}
 
-			log.Debug("Hopping on channel %d", channel)
+			log.Info("Hopping on channel %d", channel)
 
+			w.chanLock.Lock()
 			if err := network.SetInterfaceChannel(w.Session.Interface.Name(), channel); err != nil {
 				log.Warning("Error while hopping to channel %d: %s", channel, err)
 			}
+			w.chanLock.Unlock()
 
 			time.Sleep(delay)
 			if !w.Running() {