Keystore 2.0 SPI: Fix NPE in getUniqueAliases.

getUniqueAliases may return a null if an error occurred. This would lead
to a NPE in engineAliases.

This patch makes getUniqueAliases return an empty HashSet instead.

Test: atest KeystoreTests

Change-Id: I387d90ea851a8b9c18bb2b20d1a0bfc1ab76c99f

2 files changed, 56 insertions, 0 deletions

diff --git a/keystore/tests/Android.bp b/keystore/tests/Android.bp
index 2315a8568c64..7de45233494b 100644
--- a/keystore/tests/Android.bp
+++ b/keystore/tests/Android.bp
@@ -28,6 +28,7 @@ android_test {
     static_libs: [
         "androidx.test.rules",
         "hamcrest-library",
+        "mockito-target-minus-junit4",
     ],
     platform_apis: true,
     libs: ["android.test.runner"],
diff --git a/keystore/tests/src/android/security/keystore2/AndroidKeyStoreSpiTest.java b/keystore/tests/src/android/security/keystore2/AndroidKeyStoreSpiTest.java
new file mode 100644
index 000000000000..1bd3069f483a
--- /dev/null
+++ b/keystore/tests/src/android/security/keystore2/AndroidKeyStoreSpiTest.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.security.keystore2;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.anyLong;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.security.KeyStore2;
+import android.security.KeyStoreException;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+public class AndroidKeyStoreSpiTest {
+
+    @Mock
+    private KeyStore2 mKeystore2;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+    }
+
+    @Test
+    public void testEngineAliasesReturnsEmptySetOnKeyStoreError() throws Exception {
+        when(mKeystore2.list(anyInt(), anyLong()))
+                .thenThrow(new KeyStoreException(6, "Some Error"));
+        AndroidKeyStoreSpi spi = new AndroidKeyStoreSpi();
+        spi.initForTesting(mKeystore2);
+
+        assertThat("Empty collection expected", !spi.engineAliases().hasMoreElements());
+
+        verify(mKeystore2).list(anyInt(), anyLong());
+    }
+
+}