From 04bec267e436267f79332814071e807e94543d1a Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@google.com>
Date: Fri, 13 Dec 2019 17:20:31 -0800
Subject: [PATCH] [network-diagnostic] avoid reference binding to null pointer
 (#4401)

---
 src/core/thread/network_diagnostic.cpp | 10 +++++-----
 src/core/thread/network_diagnostic.hpp |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/core/thread/network_diagnostic.cpp b/src/core/thread/network_diagnostic.cpp
index bd9cd3b7d..e27fa1b4e 100644
--- a/src/core/thread/network_diagnostic.cpp
+++ b/src/core/thread/network_diagnostic.cpp
@@ -146,21 +146,21 @@ void NetworkDiagnostic::HandleDiagnosticGetResponse(void *               aContex
                                                     otError              aResult)
 {
     static_cast<NetworkDiagnostic *>(aContext)->HandleDiagnosticGetResponse(
-        *static_cast<Coap::Message *>(aMessage), *static_cast<const Ip6::MessageInfo *>(aMessageInfo), aResult);
+        static_cast<Coap::Message *>(aMessage), static_cast<const Ip6::MessageInfo *>(aMessageInfo), aResult);
 }
 
-void NetworkDiagnostic::HandleDiagnosticGetResponse(Coap::Message &         aMessage,
-                                                    const Ip6::MessageInfo &aMessageInfo,
+void NetworkDiagnostic::HandleDiagnosticGetResponse(Coap::Message *         aMessage,
+                                                    const Ip6::MessageInfo *aMessageInfo,
                                                     otError                 aResult)
 {
     VerifyOrExit(aResult == OT_ERROR_NONE);
-    VerifyOrExit(aMessage.GetCode() == OT_COAP_CODE_CHANGED);
+    VerifyOrExit(aMessage && aMessage->GetCode() == OT_COAP_CODE_CHANGED);
 
     otLogInfoNetDiag("Received diagnostic get response");
 
     if (mReceiveDiagnosticGetCallback)
     {
-        mReceiveDiagnosticGetCallback(&aMessage, &aMessageInfo, mReceiveDiagnosticGetCallbackContext);
+        mReceiveDiagnosticGetCallback(aMessage, aMessageInfo, mReceiveDiagnosticGetCallbackContext);
     }
 
 exit:
diff --git a/src/core/thread/network_diagnostic.hpp b/src/core/thread/network_diagnostic.hpp
index 6b1a20c79..4d0500c04 100644
--- a/src/core/thread/network_diagnostic.hpp
+++ b/src/core/thread/network_diagnostic.hpp
@@ -114,7 +114,7 @@ private:
                                             otMessage *          aMessage,
                                             const otMessageInfo *aMessageInfo,
                                             otError              aResult);
-    void HandleDiagnosticGetResponse(Coap::Message &aMessage, const Ip6::MessageInfo &aMessageInfo, otError aResult);
+    void HandleDiagnosticGetResponse(Coap::Message *aMessage, const Ip6::MessageInfo *aMessageInfo, otError aResult);
 
     static void HandleDiagnosticGetAnswer(void *aContext, otMessage *aMessage, const otMessageInfo *aMessageInfo);
     void        HandleDiagnosticGetAnswer(Coap::Message &aMessage, const Ip6::MessageInfo &aMessageInfo);