From 86a26927ae5fb044e895f87b1e2c48355ee1f3c5 Mon Sep 17 00:00:00 2001
From: Stefano Avallone <stavallo@unina.it>
Date: Wed, 14 Nov 2018 13:08:46 +0100
Subject: [PATCH] wifi: Avoid a potential segfault in WifiNetDevice::DoDispose

---
 src/wifi/model/wifi-net-device.cc | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/wifi/model/wifi-net-device.cc b/src/wifi/model/wifi-net-device.cc
index 272b8f225..f09e448f9 100644
--- a/src/wifi/model/wifi-net-device.cc
+++ b/src/wifi/model/wifi-net-device.cc
@@ -103,12 +103,21 @@ WifiNetDevice::DoDispose (void)
 {
   NS_LOG_FUNCTION_NOARGS ();
   m_node = 0;
-  m_mac->Dispose ();
-  m_phy->Dispose ();
-  m_stationManager->Dispose ();
-  m_mac = 0;
-  m_phy = 0;
-  m_stationManager = 0;
+  if (m_mac)
+    {
+      m_mac->Dispose ();
+      m_mac = 0;
+    }
+  if (m_phy)
+    {
+      m_phy->Dispose ();
+      m_phy = 0;
+    }
+  if (m_stationManager)
+    {
+      m_stationManager->Dispose ();
+      m_stationManager = 0;
+    }
   NetDevice::DoDispose ();
 }