| /* |
| * Copyright (C) 2019 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 com.android.server.backup.encryption.tasks; |
| |
| import static com.google.common.truth.Truth.assertThat; |
| |
| import static org.testng.Assert.assertThrows; |
| |
| import android.app.backup.BackupDataInput; |
| import android.platform.test.annotations.Presubmit; |
| import android.util.Pair; |
| |
| import com.android.server.backup.encryption.chunk.ChunkHash; |
| import com.android.server.backup.encryption.chunking.ChunkHasher; |
| import com.android.server.backup.encryption.chunking.EncryptedChunk; |
| import com.android.server.backup.encryption.kv.KeyValueListingBuilder; |
| import com.android.server.backup.encryption.protos.nano.KeyValueListingProto.KeyValueListing; |
| import com.android.server.backup.encryption.protos.nano.KeyValuePairProto.KeyValuePair; |
| import com.android.server.backup.encryption.tasks.BackupEncrypter.Result; |
| import com.android.server.testing.shadows.DataEntity; |
| import com.android.server.testing.shadows.ShadowBackupDataInput; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.ImmutableSet; |
| import com.google.common.collect.Ordering; |
| |
| import org.junit.Before; |
| import org.junit.Test; |
| import org.junit.runner.RunWith; |
| import org.robolectric.RobolectricTestRunner; |
| import org.robolectric.annotation.Config; |
| |
| import java.security.MessageDigest; |
| import java.util.Arrays; |
| import java.util.Set; |
| import java.util.stream.Collectors; |
| |
| import javax.crypto.Cipher; |
| import javax.crypto.SecretKey; |
| import javax.crypto.spec.GCMParameterSpec; |
| import javax.crypto.spec.SecretKeySpec; |
| |
| @RunWith(RobolectricTestRunner.class) |
| @Presubmit |
| @Config(shadows = {ShadowBackupDataInput.class}) |
| public class KvBackupEncrypterTest { |
| private static final String KEY_ALGORITHM = "AES"; |
| private static final String CIPHER_ALGORITHM = "AES/GCM/NoPadding"; |
| private static final int GCM_TAG_LENGTH_BYTES = 16; |
| |
| private static final byte[] TEST_TERTIARY_KEY = Arrays.copyOf(new byte[0], 256 / Byte.SIZE); |
| private static final String TEST_KEY_1 = "test_key_1"; |
| private static final String TEST_KEY_2 = "test_key_2"; |
| private static final String TEST_KEY_3 = "test_key_3"; |
| private static final byte[] TEST_VALUE_1 = {10, 11, 12}; |
| private static final byte[] TEST_VALUE_2 = {13, 14, 15}; |
| private static final byte[] TEST_VALUE_2B = {13, 14, 15, 16}; |
| private static final byte[] TEST_VALUE_3 = {16, 17, 18}; |
| |
| private SecretKey mSecretKey; |
| private ChunkHasher mChunkHasher; |
| |
| @Before |
| public void setUp() { |
| mSecretKey = new SecretKeySpec(TEST_TERTIARY_KEY, KEY_ALGORITHM); |
| mChunkHasher = new ChunkHasher(mSecretKey); |
| |
| ShadowBackupDataInput.reset(); |
| } |
| |
| private KvBackupEncrypter createEncrypter(KeyValueListing keyValueListing) { |
| KvBackupEncrypter encrypter = new KvBackupEncrypter(new BackupDataInput(null)); |
| encrypter.setOldKeyValueListing(keyValueListing); |
| return encrypter; |
| } |
| |
| @Test |
| public void backup_noExistingBackup_encryptsAllPairs() throws Exception { |
| ShadowBackupDataInput.addEntity(TEST_KEY_1, TEST_VALUE_1); |
| ShadowBackupDataInput.addEntity(TEST_KEY_2, TEST_VALUE_2); |
| |
| KeyValueListing emptyKeyValueListing = new KeyValueListingBuilder().build(); |
| ImmutableSet<ChunkHash> emptyExistingChunks = ImmutableSet.of(); |
| KvBackupEncrypter encrypter = createEncrypter(emptyKeyValueListing); |
| |
| Result result = |
| encrypter.backup( |
| mSecretKey, /*unusedFingerprintMixerSalt=*/ null, emptyExistingChunks); |
| |
| assertThat(result.getAllChunks()).hasSize(2); |
| EncryptedChunk chunk1 = result.getNewChunks().get(0); |
| EncryptedChunk chunk2 = result.getNewChunks().get(1); |
| assertThat(chunk1.key()).isEqualTo(getChunkHash(TEST_KEY_1, TEST_VALUE_1)); |
| KeyValuePair pair1 = decryptChunk(chunk1); |
| assertThat(pair1.key).isEqualTo(TEST_KEY_1); |
| assertThat(pair1.value).isEqualTo(TEST_VALUE_1); |
| assertThat(chunk2.key()).isEqualTo(getChunkHash(TEST_KEY_2, TEST_VALUE_2)); |
| KeyValuePair pair2 = decryptChunk(chunk2); |
| assertThat(pair2.key).isEqualTo(TEST_KEY_2); |
| assertThat(pair2.value).isEqualTo(TEST_VALUE_2); |
| } |
| |
| @Test |
| public void backup_existingBackup_encryptsNewAndUpdatedPairs() throws Exception { |
| Pair<KeyValueListing, Set<ChunkHash>> initialResult = runInitialBackupOfPairs1And2(); |
| |
| // Update key 2 and add the new key 3. |
| ShadowBackupDataInput.reset(); |
| ShadowBackupDataInput.addEntity(TEST_KEY_2, TEST_VALUE_2B); |
| ShadowBackupDataInput.addEntity(TEST_KEY_3, TEST_VALUE_3); |
| |
| KvBackupEncrypter encrypter = createEncrypter(initialResult.first); |
| BackupEncrypter.Result secondResult = |
| encrypter.backup( |
| mSecretKey, /*unusedFingerprintMixerSalt=*/ null, initialResult.second); |
| |
| assertThat(secondResult.getAllChunks()).hasSize(3); |
| assertThat(secondResult.getNewChunks()).hasSize(2); |
| EncryptedChunk newChunk2 = secondResult.getNewChunks().get(0); |
| EncryptedChunk newChunk3 = secondResult.getNewChunks().get(1); |
| assertThat(newChunk2.key()).isEqualTo(getChunkHash(TEST_KEY_2, TEST_VALUE_2B)); |
| assertThat(decryptChunk(newChunk2).value).isEqualTo(TEST_VALUE_2B); |
| assertThat(newChunk3.key()).isEqualTo(getChunkHash(TEST_KEY_3, TEST_VALUE_3)); |
| assertThat(decryptChunk(newChunk3).value).isEqualTo(TEST_VALUE_3); |
| } |
| |
| @Test |
| public void backup_allChunksContainsHashesOfAllChunks() throws Exception { |
| Pair<KeyValueListing, Set<ChunkHash>> initialResult = runInitialBackupOfPairs1And2(); |
| |
| ShadowBackupDataInput.reset(); |
| ShadowBackupDataInput.addEntity(TEST_KEY_3, TEST_VALUE_3); |
| |
| KvBackupEncrypter encrypter = createEncrypter(initialResult.first); |
| BackupEncrypter.Result secondResult = |
| encrypter.backup( |
| mSecretKey, /*unusedFingerprintMixerSalt=*/ null, initialResult.second); |
| |
| assertThat(secondResult.getAllChunks()) |
| .containsExactly( |
| getChunkHash(TEST_KEY_1, TEST_VALUE_1), |
| getChunkHash(TEST_KEY_2, TEST_VALUE_2), |
| getChunkHash(TEST_KEY_3, TEST_VALUE_3)); |
| } |
| |
| @Test |
| public void backup_negativeSize_deletesKeyFromExistingBackup() throws Exception { |
| Pair<KeyValueListing, Set<ChunkHash>> initialResult = runInitialBackupOfPairs1And2(); |
| |
| ShadowBackupDataInput.reset(); |
| ShadowBackupDataInput.addEntity(new DataEntity(TEST_KEY_2)); |
| |
| KvBackupEncrypter encrypter = createEncrypter(initialResult.first); |
| Result secondResult = |
| encrypter.backup( |
| mSecretKey, /*unusedFingerprintMixerSalt=*/ null, initialResult.second); |
| |
| assertThat(secondResult.getAllChunks()) |
| .containsExactly(getChunkHash(TEST_KEY_1, TEST_VALUE_1)); |
| assertThat(secondResult.getNewChunks()).isEmpty(); |
| } |
| |
| @Test |
| public void backup_returnsMessageDigestOverChunkHashes() throws Exception { |
| Pair<KeyValueListing, Set<ChunkHash>> initialResult = runInitialBackupOfPairs1And2(); |
| |
| ShadowBackupDataInput.reset(); |
| ShadowBackupDataInput.addEntity(TEST_KEY_3, TEST_VALUE_3); |
| |
| KvBackupEncrypter encrypter = createEncrypter(initialResult.first); |
| Result secondResult = |
| encrypter.backup( |
| mSecretKey, /*unusedFingerprintMixerSalt=*/ null, initialResult.second); |
| |
| MessageDigest messageDigest = |
| MessageDigest.getInstance(BackupEncrypter.MESSAGE_DIGEST_ALGORITHM); |
| ImmutableList<ChunkHash> sortedHashes = |
| Ordering.natural() |
| .immutableSortedCopy( |
| ImmutableList.of( |
| getChunkHash(TEST_KEY_1, TEST_VALUE_1), |
| getChunkHash(TEST_KEY_2, TEST_VALUE_2), |
| getChunkHash(TEST_KEY_3, TEST_VALUE_3))); |
| messageDigest.update(sortedHashes.get(0).getHash()); |
| messageDigest.update(sortedHashes.get(1).getHash()); |
| messageDigest.update(sortedHashes.get(2).getHash()); |
| assertThat(secondResult.getDigest()).isEqualTo(messageDigest.digest()); |
| } |
| |
| @Test |
| public void getNewKeyValueListing_noExistingBackup_returnsCorrectListing() throws Exception { |
| KeyValueListing keyValueListing = runInitialBackupOfPairs1And2().first; |
| |
| assertThat(keyValueListing.entries.length).isEqualTo(2); |
| assertThat(keyValueListing.entries[0].key).isEqualTo(TEST_KEY_1); |
| assertThat(keyValueListing.entries[0].hash) |
| .isEqualTo(getChunkHash(TEST_KEY_1, TEST_VALUE_1).getHash()); |
| assertThat(keyValueListing.entries[1].key).isEqualTo(TEST_KEY_2); |
| assertThat(keyValueListing.entries[1].hash) |
| .isEqualTo(getChunkHash(TEST_KEY_2, TEST_VALUE_2).getHash()); |
| } |
| |
| @Test |
| public void getNewKeyValueListing_existingBackup_returnsCorrectListing() throws Exception { |
| Pair<KeyValueListing, Set<ChunkHash>> initialResult = runInitialBackupOfPairs1And2(); |
| |
| ShadowBackupDataInput.reset(); |
| ShadowBackupDataInput.addEntity(TEST_KEY_2, TEST_VALUE_2B); |
| ShadowBackupDataInput.addEntity(TEST_KEY_3, TEST_VALUE_3); |
| |
| KvBackupEncrypter encrypter = createEncrypter(initialResult.first); |
| encrypter.backup(mSecretKey, /*unusedFingerprintMixerSalt=*/ null, initialResult.second); |
| |
| ImmutableMap<String, ChunkHash> keyValueListing = |
| listingToMap(encrypter.getNewKeyValueListing()); |
| assertThat(keyValueListing).hasSize(3); |
| assertThat(keyValueListing) |
| .containsEntry(TEST_KEY_1, getChunkHash(TEST_KEY_1, TEST_VALUE_1)); |
| assertThat(keyValueListing) |
| .containsEntry(TEST_KEY_2, getChunkHash(TEST_KEY_2, TEST_VALUE_2B)); |
| assertThat(keyValueListing) |
| .containsEntry(TEST_KEY_3, getChunkHash(TEST_KEY_3, TEST_VALUE_3)); |
| } |
| |
| @Test |
| public void getNewKeyValueChunkListing_beforeBackup_throws() throws Exception { |
| KvBackupEncrypter encrypter = createEncrypter(new KeyValueListing()); |
| assertThrows(IllegalStateException.class, encrypter::getNewKeyValueListing); |
| } |
| |
| private ImmutableMap<String, ChunkHash> listingToMap(KeyValueListing listing) { |
| // We can't use the ImmutableMap collector directly because it isn't supported in Android |
| // guava. |
| return ImmutableMap.copyOf( |
| Arrays.stream(listing.entries) |
| .collect( |
| Collectors.toMap( |
| entry -> entry.key, entry -> new ChunkHash(entry.hash)))); |
| } |
| |
| private Pair<KeyValueListing, Set<ChunkHash>> runInitialBackupOfPairs1And2() throws Exception { |
| ShadowBackupDataInput.addEntity(TEST_KEY_1, TEST_VALUE_1); |
| ShadowBackupDataInput.addEntity(TEST_KEY_2, TEST_VALUE_2); |
| |
| KeyValueListing initialKeyValueListing = new KeyValueListingBuilder().build(); |
| ImmutableSet<ChunkHash> initialExistingChunks = ImmutableSet.of(); |
| KvBackupEncrypter encrypter = createEncrypter(initialKeyValueListing); |
| Result firstResult = |
| encrypter.backup( |
| mSecretKey, /*unusedFingerprintMixerSalt=*/ null, initialExistingChunks); |
| |
| return Pair.create( |
| encrypter.getNewKeyValueListing(), ImmutableSet.copyOf(firstResult.getAllChunks())); |
| } |
| |
| private ChunkHash getChunkHash(String key, byte[] value) throws Exception { |
| KeyValuePair pair = new KeyValuePair(); |
| pair.key = key; |
| pair.value = Arrays.copyOf(value, value.length); |
| return mChunkHasher.computeHash(KeyValuePair.toByteArray(pair)); |
| } |
| |
| private KeyValuePair decryptChunk(EncryptedChunk encryptedChunk) throws Exception { |
| Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM); |
| cipher.init( |
| Cipher.DECRYPT_MODE, |
| mSecretKey, |
| new GCMParameterSpec(GCM_TAG_LENGTH_BYTES * Byte.SIZE, encryptedChunk.nonce())); |
| byte[] decryptedBytes = cipher.doFinal(encryptedChunk.encryptedBytes()); |
| return KeyValuePair.parseFrom(decryptedBytes); |
| } |
| } |