From d88e74870ddfe19f20c123e45bc6afe54319db42 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabi=C3=A1n=20Kozynski?= <kozynski@google.com>
Date: Thu, 15 Jun 2023 12:30:06 -0400
Subject: [PATCH] Prevent NPE on race condition

There could be a race condition where there is a dispatch to mCallback
after it's been nulled, due to the dispatch happening not on the same
thread. Check if the callback has been nulled.

Fixes: 287421329
Test: build
Change-Id: Idaa0c106ff034ea55b08bf4230565aa3cae6f6a8
---
 .../dialog/InternetDialogController.java      | 39 ++++++++++++++-----
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/qs/tiles/dialog/InternetDialogController.java b/packages/SystemUI/src/com/android/systemui/qs/tiles/dialog/InternetDialogController.java
index 9d2c8acd9522a..ec1258049486d 100644
--- a/packages/SystemUI/src/com/android/systemui/qs/tiles/dialog/InternetDialogController.java
+++ b/packages/SystemUI/src/com/android/systemui/qs/tiles/dialog/InternetDialogController.java
@@ -173,6 +173,7 @@ public class InternetDialogController implements AccessPointController.AccessPoi
     private AccessPointController mAccessPointController;
     private IntentFilter mConnectionStateFilter;
     @VisibleForTesting
+    @Nullable
     InternetDialogCallback mCallback;
     private UiEventLogger mUiEventLogger;
     private BroadcastDispatcher mBroadcastDispatcher;
@@ -730,7 +731,7 @@ public class InternetDialogController implements AccessPointController.AccessPoi
         ActivityLaunchAnimator.Controller controller =
                 mDialogLaunchAnimator.createActivityLaunchController(view);
 
-        if (controller == null) {
+        if (controller == null && mCallback != null) {
             mCallback.dismissDialog();
         }
 
@@ -1101,7 +1102,9 @@ public class InternetDialogController implements AccessPointController.AccessPoi
             mHasWifiEntries = false;
         }
 
-        mCallback.onAccessPointsChanged(wifiEntries, connectedEntry, hasMoreWifiEntries);
+        if (mCallback != null) {
+            mCallback.onAccessPointsChanged(wifiEntries, connectedEntry, hasMoreWifiEntries);
+        }
     }
 
     @Override
@@ -1123,34 +1126,46 @@ public class InternetDialogController implements AccessPointController.AccessPoi
 
         @Override
         public void onServiceStateChanged(@NonNull ServiceState serviceState) {
-            mCallback.onServiceStateChanged(serviceState);
+            if (mCallback != null) {
+                mCallback.onServiceStateChanged(serviceState);
+            }
         }
 
         @Override
         public void onDataConnectionStateChanged(int state, int networkType) {
-            mCallback.onDataConnectionStateChanged(state, networkType);
+            if (mCallback != null) {
+                mCallback.onDataConnectionStateChanged(state, networkType);
+            }
         }
 
         @Override
         public void onSignalStrengthsChanged(@NonNull SignalStrength signalStrength) {
-            mCallback.onSignalStrengthsChanged(signalStrength);
+            if (mCallback != null) {
+                mCallback.onSignalStrengthsChanged(signalStrength);
+            }
         }
 
         @Override
         public void onDisplayInfoChanged(@NonNull TelephonyDisplayInfo telephonyDisplayInfo) {
             mSubIdTelephonyDisplayInfoMap.put(mSubId, telephonyDisplayInfo);
-            mCallback.onDisplayInfoChanged(telephonyDisplayInfo);
+            if (mCallback != null) {
+                mCallback.onDisplayInfoChanged(telephonyDisplayInfo);
+            }
         }
 
         @Override
         public void onUserMobileDataStateChanged(boolean enabled) {
-            mCallback.onUserMobileDataStateChanged(enabled);
+            if (mCallback != null) {
+                mCallback.onUserMobileDataStateChanged(enabled);
+            }
         }
 
         @Override
         public void onCarrierNetworkChange(boolean active) {
             mCarrierNetworkChangeMode = active;
-            mCallback.onCarrierNetworkChange(active);
+            if (mCallback != null) {
+                mCallback.onCarrierNetworkChange(active);
+            }
         }
     }
 
@@ -1177,14 +1192,18 @@ public class InternetDialogController implements AccessPointController.AccessPoi
                 scanWifiAccessPoints();
             }
             // update UI
-            mCallback.onCapabilitiesChanged(network, capabilities);
+            if (mCallback != null) {
+                mCallback.onCapabilitiesChanged(network, capabilities);
+            }
         }
 
         @Override
         @WorkerThread
         public void onLost(@NonNull Network network) {
             mHasEthernet = false;
-            mCallback.onLost(network);
+            if (mCallback != null) {
+                mCallback.onLost(network);
+            }
         }
     }