Import the code related to Key/Value backup encryption (668c05eb) · Commits · e / os / android_frameworks_base

packages/BackupEncryption/proto/key_value_listing.proto

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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
		*/

		syntax = "proto2";

		package android_backup_crypto;

		option java_package = "com.android.server.backup.encryption.protos";
		option java_outer_classname = "KeyValueListingProto";

		// An entry of a key-value pair.
		message KeyValueEntry {
		// Plaintext key of the key-value pair.
		optional string key = 1;
		// SHA-256 MAC of the plaintext of the chunk containing the pair
		optional bytes hash = 2;
		}

		// Describes the key/value pairs currently in the backup blob, mapping from the
		// plaintext key to the hash of the chunk containing the pair.
		//
		// This is local state stored on the device. It is never sent to the
		// backup server. See ChunkOrdering for how the device restores the
		// key-value pairs in the correct order.
		message KeyValueListing {
		repeated KeyValueEntry entries = 1;
		}

packages/BackupEncryption/proto/key_value_pair.proto

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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
		*/

		syntax = "proto2";

		package android_backup_crypto;

		option java_package = "com.android.server.backup.encryption.protos";
		option java_outer_classname = "KeyValuePairProto";

		// Serialized form of a key-value pair, when it is to be encrypted in a blob.
		// The backup blob for a key-value database consists of repeated encrypted
		// key-value pairs like this, in a randomized order. See ChunkOrdering for how
		// these are then reconstructed during a restore.
		message KeyValuePair {
		optional string key = 1;
		optional bytes value = 2;
		}

packages/BackupEncryption/src/com/android/server/backup/encryption/kv/DecryptedChunkKvOutput.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.kv;

		import static com.android.internal.util.Preconditions.checkState;

		import com.android.internal.annotations.VisibleForTesting;
		import com.android.server.backup.encryption.chunk.ChunkHash;
		import com.android.server.backup.encryption.chunking.ChunkHasher;
		import com.android.server.backup.encryption.protos.nano.KeyValuePairProto;
		import com.android.server.backup.encryption.tasks.DecryptedChunkOutput;

		import java.io.IOException;
		import java.security.InvalidKeyException;
		import java.security.MessageDigest;
		import java.security.NoSuchAlgorithmException;
		import java.util.ArrayList;
		import java.util.Arrays;
		import java.util.Collections;
		import java.util.Comparator;
		import java.util.List;

		/**
		* Builds a key value backup set from plaintext chunks. Computes a digest over the sorted SHA-256
		* hashes of the chunks.
		*/
		public class DecryptedChunkKvOutput implements DecryptedChunkOutput {
		@VisibleForTesting static final String DIGEST_ALGORITHM = "SHA-256";

		private final ChunkHasher mChunkHasher;
		private final List<KeyValuePairProto.KeyValuePair> mUnsortedPairs = new ArrayList<>();
		private final List<ChunkHash> mUnsortedHashes = new ArrayList<>();
		private boolean mClosed;

		/** Constructs a new instance which computers the digest using the given hasher. */
		public DecryptedChunkKvOutput(ChunkHasher chunkHasher) {
		mChunkHasher = chunkHasher;
		}

		@Override
		public DecryptedChunkOutput open() {
		// As we don't have any resources there is nothing to open.
		return this;
		}

		@Override
		public void processChunk(byte[] plaintextBuffer, int length)
		throws IOException, InvalidKeyException {
		checkState(!mClosed, "Cannot process chunk after close()");
		KeyValuePairProto.KeyValuePair kvPair = new KeyValuePairProto.KeyValuePair();
		KeyValuePairProto.KeyValuePair.mergeFrom(kvPair, plaintextBuffer, 0, length);
		mUnsortedPairs.add(kvPair);
		// TODO(b/71492289): Update ChunkHasher to accept offset and length so we don't have to copy
		// the buffer into a smaller array.
		mUnsortedHashes.add(mChunkHasher.computeHash(Arrays.copyOf(plaintextBuffer, length)));
		}

		@Override
		public void close() {
		// As we don't have any resources there is nothing to close.
		mClosed = true;
		}

		@Override
		public byte[] getDigest() throws NoSuchAlgorithmException {
		checkState(mClosed, "Must close() before getDigest()");
		MessageDigest digest = getMessageDigest();
		Collections.sort(mUnsortedHashes);
		for (ChunkHash hash : mUnsortedHashes) {
		digest.update(hash.getHash());
		}
		return digest.digest();
		}

		private static MessageDigest getMessageDigest() throws NoSuchAlgorithmException {
		return MessageDigest.getInstance(DIGEST_ALGORITHM);
		}

		/**
		* Returns the key value pairs from the backup, sorted lexicographically by key.
		*
		* <p>You must call {@link #close} first.
		*/
		public List<KeyValuePairProto.KeyValuePair> getPairs() {
		checkState(mClosed, "Must close() before getPairs()");
		Collections.sort(
		mUnsortedPairs,
		new Comparator<KeyValuePairProto.KeyValuePair>() {
		@Override
		public int compare(
		KeyValuePairProto.KeyValuePair o1, KeyValuePairProto.KeyValuePair o2) {
		return o1.key.compareTo(o2.key);
		}
		});
		return mUnsortedPairs;
		}
		}

packages/BackupEncryption/src/com/android/server/backup/encryption/kv/KeyValueListingBuilder.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.kv;

		import static com.android.internal.util.Preconditions.checkArgument;
		import static com.android.internal.util.Preconditions.checkNotNull;

		import com.android.server.backup.encryption.chunk.ChunkHash;
		import com.android.server.backup.encryption.protos.nano.KeyValueListingProto;

		import java.util.ArrayList;
		import java.util.List;
		import java.util.Map;
		import java.util.Map.Entry;

		/**
		* Builds a {@link KeyValueListingProto.KeyValueListing}, which is a nano proto and so has no
		* builder.
		*/
		public class KeyValueListingBuilder {
		private final List<KeyValueListingProto.KeyValueEntry> mEntries = new ArrayList<>();

		/** Adds a new pair entry to the listing. */
		public KeyValueListingBuilder addPair(String key, ChunkHash hash) {
		checkArgument(key.length() != 0, "Key must have non-zero length");
		checkNotNull(hash, "Hash must not be null");

		KeyValueListingProto.KeyValueEntry entry = new KeyValueListingProto.KeyValueEntry();
		entry.key = key;
		entry.hash = hash.getHash();
		mEntries.add(entry);

		return this;
		}

		/** Adds all pairs contained in a map, where the map is from key to hash. */
		public KeyValueListingBuilder addAll(Map<String, ChunkHash> map) {
		for (Entry<String, ChunkHash> entry : map.entrySet()) {
		addPair(entry.getKey(), entry.getValue());
		}

		return this;
		}

		/** Returns a new listing containing all the pairs added so far. */
		public KeyValueListingProto.KeyValueListing build() {
		if (mEntries.size() == 0) {
		return emptyListing();
		}

		KeyValueListingProto.KeyValueListing listing = new KeyValueListingProto.KeyValueListing();
		listing.entries = new KeyValueListingProto.KeyValueEntry[mEntries.size()];
		mEntries.toArray(listing.entries);
		return listing;
		}

		/** Returns a new listing which does not contain any pairs. */
		public static KeyValueListingProto.KeyValueListing emptyListing() {
		KeyValueListingProto.KeyValueListing listing = new KeyValueListingProto.KeyValueListing();
		listing.entries = KeyValueListingProto.KeyValueEntry.emptyArray();
		return listing;
		}
		}

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

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		@@ -19,6 +19,7 @@ package com.android.server.backup.encryption.tasks;
		import java.io.Closeable;
		import java.io.IOException;
		import java.security.InvalidKeyException;
		import java.security.NoSuchAlgorithmException;

		/**
		* Accepts the plaintext bytes of decrypted chunks and writes them to some output. Also keeps track
		@@ -30,7 +31,7 @@ public interface DecryptedChunkOutput extends Closeable {
		*
		* @return {@code this}, to allow use with try-with-resources
		*/
		DecryptedChunkOutput open() throws IOException;
		DecryptedChunkOutput open() throws IOException, NoSuchAlgorithmException;

		/**
		* Writes the plaintext bytes of chunk to whatever output the implementation chooses. Also
		@@ -43,12 +44,13 @@ public interface DecryptedChunkOutput extends Closeable {
		* at index 0.
		* @param length The length in bytes of the plaintext contained in {@code plaintextBuffer}.
		*/
		void processChunk(byte[] plaintextBuffer, int length) throws IOException, InvalidKeyException;
		void processChunk(byte[] plaintextBuffer, int length)
		throws IOException, InvalidKeyException, NoSuchAlgorithmException;

		/**
		* Returns the message digest of all the chunks processed by {@link #processChunk}.
		*
		* <p>You must call {@link Closeable#close()} before calling this method.
		*/
		byte[] getDigest();
		byte[] getDigest() throws NoSuchAlgorithmException;
		}