From 2dd109d2385e555491f58741db78a4ebb0dcbafa Mon Sep 17 00:00:00 2001
From: Tony Mak <tonymak@google.com>
Date: Thu, 4 May 2017 11:42:31 +0100
Subject: [PATCH] Add null checking and exception handling in
 selectBackupTransportAsync

Bug: 37304539

Test: bit FrameworksServicesTests:com.android.server.backup.TrampolineTest

Change-Id: I01ffa25bfca6ca743220ee7277c2a6473c055bf1
---
 .../com/android/server/backup/Trampoline.java |  8 ++++-
 .../android/server/backup/TrampolineTest.java | 34 ++++++++++++++++++-
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/services/backup/java/com/android/server/backup/Trampoline.java b/services/backup/java/com/android/server/backup/Trampoline.java
index 1e56e95fbb904..9e7a29e036fc2 100644
--- a/services/backup/java/com/android/server/backup/Trampoline.java
+++ b/services/backup/java/com/android/server/backup/Trampoline.java
@@ -357,7 +357,13 @@ public class Trampoline extends IBackupManager.Stub {
         if (svc != null) {
             svc.selectBackupTransportAsync(transport, listener);
         } else {
-            listener.onFailure(BackupManager.ERROR_BACKUP_NOT_ALLOWED);
+            if (listener != null) {
+                try {
+                    listener.onFailure(BackupManager.ERROR_BACKUP_NOT_ALLOWED);
+                } catch (RemoteException ex) {
+                    // ignore
+                }
+            }
         }
     }
 
diff --git a/services/tests/servicestests/src/com/android/server/backup/TrampolineTest.java b/services/tests/servicestests/src/com/android/server/backup/TrampolineTest.java
index 4c53915c79e2c..27ef9d791f4c6 100644
--- a/services/tests/servicestests/src/com/android/server/backup/TrampolineTest.java
+++ b/services/tests/servicestests/src/com/android/server/backup/TrampolineTest.java
@@ -56,7 +56,6 @@ import java.io.File;
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.io.PrintWriter;
-import java.util.concurrent.LinkedBlockingDeque;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
 
@@ -599,6 +598,39 @@ public class TrampolineTest {
         assertEquals(BackupManager.ERROR_BACKUP_NOT_ALLOWED, (int) errorCode);
     }
 
+    @Test
+    public void selectBackupTransportAsync_calledBeforeInitialize_ignored_nullListener()
+            throws Exception {
+        mTrampoline.selectBackupTransportAsync(TRANSPORT_COMPONENT_NAME, null);
+        verifyNoMoreInteractions(mBackupManagerServiceMock);
+        // No crash.
+    }
+
+    @Test
+    public void selectBackupTransportAsync_calledBeforeInitialize_ignored_listenerThrowException()
+            throws Exception {
+        mTrampoline.selectBackupTransportAsync(
+                TRANSPORT_COMPONENT_NAME,
+                new ISelectBackupTransportCallback() {
+                    @Override
+                    public void onSuccess(String transportName) throws RemoteException {
+
+                    }
+
+                    @Override
+                    public void onFailure(int reason) throws RemoteException {
+                        throw new RemoteException("Crash");
+                    }
+
+                    @Override
+                    public IBinder asBinder() {
+                        return null;
+                    }
+                });
+        verifyNoMoreInteractions(mBackupManagerServiceMock);
+        // No crash.
+    }
+
     @Test
     public void selectBackupTransportAsync_forwarded() throws RemoteException {
         mTrampoline.initialize(UserHandle.USER_SYSTEM);