ScanRequestProxy: Return copy of list in getScanResults

Return a copy of internal list to prevent external
modification.

Bug: 160751554
Test: atest FrameworksWifiTests
Change-Id: Id7f8c05160d0d480077327d56dec03080708b375
Merged-In: Id7f8c05160d0d480077327d56dec03080708b375
(cherry picked from commit 48e1bcfb68371999d968c4527791d302be3140b4)

2 files changed, 17 insertions, 1 deletions

diff --git a/service/java/com/android/server/wifi/ScanRequestProxy.java b/service/java/com/android/server/wifi/ScanRequestProxy.java
index c054b90a4..622fcdab9 100644
--- a/service/java/com/android/server/wifi/ScanRequestProxy.java
+++ b/service/java/com/android/server/wifi/ScanRequestProxy.java
@@ -464,7 +464,8 @@ public class ScanRequestProxy {
      * @return the list of results
      */
     public List<ScanResult> getScanResults() {
-        return mLastScanResults;
+        // return a copy to prevent external modification
+        return new ArrayList<>(mLastScanResults);
     }
 
     /**
diff --git a/tests/wifitests/src/com/android/server/wifi/ScanRequestProxyTest.java b/tests/wifitests/src/com/android/server/wifi/ScanRequestProxyTest.java
index b065f823c..cc96602d5 100644
--- a/tests/wifitests/src/com/android/server/wifi/ScanRequestProxyTest.java
+++ b/tests/wifitests/src/com/android/server/wifi/ScanRequestProxyTest.java
@@ -22,6 +22,8 @@ import static com.android.server.wifi.ScanRequestProxy.SCAN_REQUEST_THROTTLE_MAX
 import static com.android.server.wifi.ScanRequestProxy.SCAN_REQUEST_THROTTLE_TIME_WINDOW_FG_APPS_MS;
 import static com.android.server.wifi.WifiSettingsConfigStore.WIFI_SCAN_THROTTLE_ENABLED;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
@@ -1009,6 +1011,19 @@ public class ScanRequestProxyTest extends WifiBaseTest {
         mLooper.dispatchAll();
         validateScanResultsAvailableBroadcastSent(true);
         verify(mScanResultsCallback, never()).onScanResultsAvailable();
+    }
+
+    /** Test that modifying the returned scan results list does not change the original. */
+    @Test
+    public void testGetScanResults_modifyReturnedList_doesNotChangeOriginal() {
+        // initialize scan results
+        testStartScanSuccess();
+
+        List<ScanResult> scanResults = mScanRequestProxy.getScanResults();
+        int scanResultsOriginalSize = scanResults.size();
+
+        scanResults.add(new ScanResult());
 
+        assertThat(mScanRequestProxy.getScanResults()).hasSize(scanResultsOriginalSize);
     }
 }