Import EncryptedKvBackupTask (f45db5e3) · Commits · e / os / android_frameworks_base

packages/BackupEncryption/src/com/android/server/backup/encryption/tasks/EncryptedKvBackupTask.java

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		/*
		* 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 android.annotation.Nullable;
		import android.app.backup.BackupDataInput;
		import android.content.Context;
		import android.os.ParcelFileDescriptor;
		import android.security.keystore.recovery.InternalRecoveryServiceException;
		import android.security.keystore.recovery.LockScreenRequiredException;
		import android.util.Pair;
		import android.util.Slog;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.server.backup.encryption.CryptoSettings;
		import com.android.server.backup.encryption.chunking.ProtoStore;
		import com.android.server.backup.encryption.client.CryptoBackupServer;
		import com.android.server.backup.encryption.keys.RecoverableKeyStoreSecondaryKey;
		import com.android.server.backup.encryption.keys.RecoverableKeyStoreSecondaryKeyManager;
		import com.android.server.backup.encryption.keys.TertiaryKeyManager;
		import com.android.server.backup.encryption.keys.TertiaryKeyRotationScheduler;
		import com.android.server.backup.encryption.protos.nano.ChunksMetadataProto;
		import com.android.server.backup.encryption.protos.nano.KeyValueListingProto;

		import java.io.IOException;
		import java.lang.reflect.InvocationTargetException;
		import java.security.GeneralSecurityException;
		import java.security.InvalidKeyException;
		import java.security.SecureRandom;
		import java.security.UnrecoverableKeyException;
		import java.util.Optional;

		// TODO(b/141975695): Create a base class for EncryptedKvBackupTask and EncryptedFullBackupTask.
		/** Performs encrypted key value backup, handling rotating the tertiary key as necessary. */
		public class EncryptedKvBackupTask {
		private static final String TAG = "EncryptedKvBackupTask";

		private final TertiaryKeyManager mTertiaryKeyManager;
		private final RecoverableKeyStoreSecondaryKey mSecondaryKey;
		private final ProtoStore<KeyValueListingProto.KeyValueListing> mKeyValueListingStore;
		private final ProtoStore<ChunksMetadataProto.ChunkListing> mChunkListingStore;
		private final KvBackupEncrypter mKvBackupEncrypter;
		private final EncryptedBackupTask mEncryptedBackupTask;
		private final String mPackageName;

		/** Constructs new instances of {@link EncryptedKvBackupTask}. */
		public static class EncryptedKvBackupTaskFactory {
		/**
		* Creates a new instance.
		*
		* <p>Either initializes encrypted backup or loads an existing secondary key as necessary.
		*
		* @param cryptoSettings to load secondary key state from
		* @param fileDescriptor to read the backup data from
		*/
		public EncryptedKvBackupTask newInstance(
		Context context,
		SecureRandom secureRandom,
		CryptoBackupServer cryptoBackupServer,
		CryptoSettings cryptoSettings,
		RecoverableKeyStoreSecondaryKeyManager
		.RecoverableKeyStoreSecondaryKeyManagerProvider
		recoverableSecondaryKeyManagerProvider,
		ParcelFileDescriptor fileDescriptor,
		String packageName)
		throws IOException, UnrecoverableKeyException, LockScreenRequiredException,
		InternalRecoveryServiceException, InvalidKeyException {
		RecoverableKeyStoreSecondaryKey secondaryKey =
		new InitializeRecoverableSecondaryKeyTask(
		context,
		cryptoSettings,
		recoverableSecondaryKeyManagerProvider.get(),
		cryptoBackupServer)
		.run();
		KvBackupEncrypter backupEncrypter =
		new KvBackupEncrypter(new BackupDataInput(fileDescriptor.getFileDescriptor()));
		TertiaryKeyManager tertiaryKeyManager =
		new TertiaryKeyManager(
		context,
		secureRandom,
		TertiaryKeyRotationScheduler.getInstance(context),
		secondaryKey,
		packageName);

		return new EncryptedKvBackupTask(
		tertiaryKeyManager,
		ProtoStore.createKeyValueListingStore(context),
		secondaryKey,
		ProtoStore.createChunkListingStore(context),
		backupEncrypter,
		new EncryptedBackupTask(
		cryptoBackupServer, secureRandom, packageName, backupEncrypter),
		packageName);
		}
		}

		@VisibleForTesting
		EncryptedKvBackupTask(
		TertiaryKeyManager tertiaryKeyManager,
		ProtoStore<KeyValueListingProto.KeyValueListing> keyValueListingStore,
		RecoverableKeyStoreSecondaryKey secondaryKey,
		ProtoStore<ChunksMetadataProto.ChunkListing> chunkListingStore,
		KvBackupEncrypter kvBackupEncrypter,
		EncryptedBackupTask encryptedBackupTask,
		String packageName) {
		mTertiaryKeyManager = tertiaryKeyManager;
		mSecondaryKey = secondaryKey;
		mKeyValueListingStore = keyValueListingStore;
		mChunkListingStore = chunkListingStore;
		mKvBackupEncrypter = kvBackupEncrypter;
		mEncryptedBackupTask = encryptedBackupTask;
		mPackageName = packageName;
		}

		/**
		* Reads backup data from the file descriptor provided in the construtor, encrypts it and
		* uploads it to the server.
		*
		* <p>The {@code incremental} flag indicates if the backup data provided is incremental or a
		* complete set. Incremental backup is not possible if no previous crypto state exists, or the
		* tertiary key must be rotated in the next backup. If the caller requests incremental backup
		* but it is not possible, then the backup will not start and this method will throw {@link
		* NonIncrementalBackupRequiredException}.
		*
		* <p>TODO(b/70704456): Update return code to indicate that we require non-incremental backup.
		*
		* @param incremental {@code true} if the data provided is a diff from the previous backup,
		* {@code false} if it is a complete set
		* @throws NonIncrementalBackupRequiredException if the caller provides an incremental backup but the task
		* requires non-incremental backup
		*/
		public void performBackup(boolean incremental)
		throws GeneralSecurityException, IOException, NoSuchMethodException,
		InstantiationException, IllegalAccessException, InvocationTargetException,
		NonIncrementalBackupRequiredException {
		if (mTertiaryKeyManager.wasKeyRotated()) {
		Slog.d(TAG, "Tertiary key is new so clearing package state.");
		deleteListings(mPackageName);
		}

		Optional<Pair<KeyValueListingProto.KeyValueListing, ChunksMetadataProto.ChunkListing>>
		oldListings = getListingsAndEnsureConsistency(mPackageName);

		if (oldListings.isPresent() && !incremental) {
		Slog.d(
		TAG,
		"Non-incremental backup requested but incremental state existed, clearing it");
		deleteListings(mPackageName);
		oldListings = Optional.empty();
		}

		if (!oldListings.isPresent() && incremental) {
		// If we don't have any state then we require a non-incremental backup, but this backup
		// is incremental.
		throw new NonIncrementalBackupRequiredException();
		}

		if (oldListings.isPresent()) {
		mKvBackupEncrypter.setOldKeyValueListing(oldListings.get().first);
		}

		ChunksMetadataProto.ChunkListing newChunkListing;
		if (oldListings.isPresent()) {
		Slog.v(TAG, "Old listings existed, performing incremental backup");
		newChunkListing =
		mEncryptedBackupTask.performIncrementalBackup(
		mTertiaryKeyManager.getKey(),
		mTertiaryKeyManager.getWrappedKey(),
		oldListings.get().second);
		} else {
		Slog.v(TAG, "Old listings did not exist, performing non-incremental backup");
		// kv backups don't use this salt because they don't involve content-defined chunking.
		byte[] fingerprintMixerSalt = null;
		newChunkListing =
		mEncryptedBackupTask.performNonIncrementalBackup(
		mTertiaryKeyManager.getKey(),
		mTertiaryKeyManager.getWrappedKey(),
		fingerprintMixerSalt);
		}

		Slog.v(TAG, "Backup and upload succeeded, saving new listings");
		saveListings(mPackageName, mKvBackupEncrypter.getNewKeyValueListing(), newChunkListing);
		}

		private Optional<Pair<KeyValueListingProto.KeyValueListing, ChunksMetadataProto.ChunkListing>>
		getListingsAndEnsureConsistency(String packageName)
		throws IOException, InvocationTargetException, NoSuchMethodException,
		InstantiationException, IllegalAccessException {
		Optional<KeyValueListingProto.KeyValueListing> keyValueListing =
		mKeyValueListingStore.loadProto(packageName);
		Optional<ChunksMetadataProto.ChunkListing> chunkListing =
		mChunkListingStore.loadProto(packageName);

		// Normally either both protos exist or neither exist, but we correct this just in case.
		boolean bothPresent = keyValueListing.isPresent() && chunkListing.isPresent();
		if (!bothPresent) {
		Slog.d(
		TAG,
		"Both listing were not present, clearing state, key value="
		+ keyValueListing.isPresent()
		+ ", chunk="
		+ chunkListing.isPresent());
		deleteListings(packageName);
		return Optional.empty();
		}

		return Optional.of(Pair.create(keyValueListing.get(), chunkListing.get()));
		}

		private void saveListings(
		String packageName,
		KeyValueListingProto.KeyValueListing keyValueListing,
		ChunksMetadataProto.ChunkListing chunkListing) {
		try {
		mKeyValueListingStore.saveProto(packageName, keyValueListing);
		mChunkListingStore.saveProto(packageName, chunkListing);
		} catch (IOException e) {
		// If a problem occurred while saving either listing then they may be inconsistent, so
		// delete
		// both.
		Slog.w(TAG, "Unable to save listings, deleting both for consistency", e);
		deleteListings(packageName);
		}
		}

		private void deleteListings(String packageName) {
		mKeyValueListingStore.deleteProto(packageName);
		mChunkListingStore.deleteProto(packageName);
		}
		}

packages/BackupEncryption/src/com/android/server/backup/encryption/tasks/NonIncrementalBackupRequiredException.java

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		/*
		* 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;

		// TODO(141840878): Update documentation.
		/**
		* Exception thrown when the framework provides an incremental backup but the transport requires a
		* non-incremental backup.
		*/
		public class NonIncrementalBackupRequiredException extends Exception {}

packages/BackupEncryption/test/robolectric/src/com/android/server/backup/encryption/tasks/EncryptedKvBackupTaskTest.java

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packages/BackupEncryption/test/robolectric/src/com/android/server/testing/CryptoTestUtils.java

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		@@ -16,6 +16,8 @@

		package com.android.server.backup.testing;

		import android.util.Pair;

		import com.android.server.backup.encryption.chunk.ChunkHash;
		import com.android.server.backup.encryption.protos.nano.ChunksMetadataProto;
		import com.android.server.backup.encryption.protos.nano.KeyValuePairProto;
		@@ -23,6 +25,8 @@ import com.android.server.backup.encryption.protos.nano.KeyValuePairProto;
		import java.nio.charset.Charset;
		import java.security.NoSuchAlgorithmException;
		import java.util.Arrays;
		import java.util.HashMap;
		import java.util.Map;
		import java.util.Random;

		import javax.crypto.KeyGenerator;
		@@ -162,4 +166,12 @@ public class CryptoTestUtils {
		clone.checksum = Arrays.copyOf(original.checksum, original.checksum.length);
		return clone;
		}

		public static <K, V> Map<K, V> mapOf(Pair<K, V>... pairs) {
		Map<K, V> map = new HashMap<>();
		for (Pair<K, V> pair : pairs) {
		map.put(pair.first, pair.second);
		}
		return map;
		}
		}