Merge "Import the code related to Key/Value backup encryption"

packages/BackupEncryption/proto/key_value_listing.proto

@@ -0,0 +1,40 @@
+/*
+ * 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

@@ -0,0 +1,31 @@
+/*
+ * 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

@@ -0,0 +1,111 @@
+/*
+ * 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

@@ -0,0 +1,77 @@
+/*
+ * 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

@@ -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;
 }

packages/BackupEncryption/test/robolectric/src/com/android/server/backup/encryption/kv/DecryptedChunkKvOutputTest.java

@@ -0,0 +1,164 @@
+/*
+ * 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.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
+import static org.testng.Assert.assertThrows;
+
+import android.os.Debug;
+import android.platform.test.annotations.Presubmit;
+
+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 org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+
+import java.security.MessageDigest;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Stream;
+
+@RunWith(RobolectricTestRunner.class)
+@Presubmit
+public class DecryptedChunkKvOutputTest {
+    private static final String TEST_KEY_1 = "key_1";
+    private static final String TEST_KEY_2 = "key_2";
+    private static final byte[] TEST_VALUE_1 = {1, 2, 3};
+    private static final byte[] TEST_VALUE_2 = {10, 11, 12, 13};
+    private static final byte[] TEST_PAIR_1 = toByteArray(createPair(TEST_KEY_1, TEST_VALUE_1));
+    private static final byte[] TEST_PAIR_2 = toByteArray(createPair(TEST_KEY_2, TEST_VALUE_2));
+    private static final int TEST_BUFFER_SIZE = Math.max(TEST_PAIR_1.length, TEST_PAIR_2.length);
+
+    @Mock private ChunkHasher mChunkHasher;
+    private DecryptedChunkKvOutput mOutput;
+
+    @Before
+    public void setUp() throws Exception {
+        MockitoAnnotations.initMocks(this);
+
+        when(mChunkHasher.computeHash(any()))
+                .thenAnswer(invocation -> fakeHash(invocation.getArgument(0)));
+        mOutput = new DecryptedChunkKvOutput(mChunkHasher);
+    }
+
+    @Test
+    public void open_returnsInstance() throws Exception {
+        assertThat(mOutput.open()).isEqualTo(mOutput);
+    }
+
+    @Test
+    public void processChunk_alreadyClosed_throws() throws Exception {
+        mOutput.open();
+        mOutput.close();
+
+        assertThrows(
+                IllegalStateException.class,
+                () -> mOutput.processChunk(TEST_PAIR_1, TEST_PAIR_1.length));
+    }
+
+    @Test
+    public void getDigest_beforeClose_throws() throws Exception {
+        // TODO: b/141356823 We should add a test which calls .open() here
+        assertThrows(IllegalStateException.class, () -> mOutput.getDigest());
+    }
+
+    @Test
+    public void getDigest_returnsDigestOfSortedHashes() throws Exception {
+        mOutput.open();
+        Debug.waitForDebugger();
+        mOutput.processChunk(Arrays.copyOf(TEST_PAIR_1, TEST_BUFFER_SIZE), TEST_PAIR_1.length);
+        mOutput.processChunk(Arrays.copyOf(TEST_PAIR_2, TEST_BUFFER_SIZE), TEST_PAIR_2.length);
+        mOutput.close();
+
+        byte[] actualDigest = mOutput.getDigest();
+
+        MessageDigest digest = MessageDigest.getInstance(DecryptedChunkKvOutput.DIGEST_ALGORITHM);
+        Stream.of(TEST_PAIR_1, TEST_PAIR_2)
+                .map(DecryptedChunkKvOutputTest::fakeHash)
+                .sorted(Comparator.naturalOrder())
+                .forEachOrdered(hash -> digest.update(hash.getHash()));
+        assertThat(actualDigest).isEqualTo(digest.digest());
+    }
+
+    @Test
+    public void getPairs_beforeClose_throws() throws Exception {
+        // TODO: b/141356823 We should add a test which calls .open() here
+        assertThrows(IllegalStateException.class, () -> mOutput.getPairs());
+    }
+
+    @Test
+    public void getPairs_returnsPairsSortedByKey() throws Exception {
+        mOutput.open();
+        // Write out of order to check that it sorts the chunks.
+        mOutput.processChunk(Arrays.copyOf(TEST_PAIR_2, TEST_BUFFER_SIZE), TEST_PAIR_2.length);
+        mOutput.processChunk(Arrays.copyOf(TEST_PAIR_1, TEST_BUFFER_SIZE), TEST_PAIR_1.length);
+        mOutput.close();
+
+        List<KeyValuePairProto.KeyValuePair> pairs = mOutput.getPairs();
+
+        assertThat(
+                        isInOrder(
+                                pairs,
+                                Comparator.comparing(
+                                        (KeyValuePairProto.KeyValuePair pair) -> pair.key)))
+                .isTrue();
+        assertThat(pairs).hasSize(2);
+        assertThat(pairs.get(0).key).isEqualTo(TEST_KEY_1);
+        assertThat(pairs.get(0).value).isEqualTo(TEST_VALUE_1);
+        assertThat(pairs.get(1).key).isEqualTo(TEST_KEY_2);
+        assertThat(pairs.get(1).value).isEqualTo(TEST_VALUE_2);
+    }
+
+    private static KeyValuePairProto.KeyValuePair createPair(String key, byte[] value) {
+        KeyValuePairProto.KeyValuePair pair = new KeyValuePairProto.KeyValuePair();
+        pair.key = key;
+        pair.value = value;
+        return pair;
+    }
+
+    private boolean isInOrder(
+            List<KeyValuePairProto.KeyValuePair> list,
+            Comparator<KeyValuePairProto.KeyValuePair> comparator) {
+        if (list.size() < 2) {
+            return true;
+        }
+
+        List<KeyValuePairProto.KeyValuePair> sortedList = new ArrayList<>(list);
+        Collections.sort(sortedList, comparator);
+        return list.equals(sortedList);
+    }
+
+    private static byte[] toByteArray(KeyValuePairProto.KeyValuePair nano) {
+        return KeyValuePairProto.KeyValuePair.toByteArray(nano);
+    }
+
+    private static ChunkHash fakeHash(byte[] data) {
+        return new ChunkHash(Arrays.copyOf(data, ChunkHash.HASH_LENGTH_BYTES));
+    }
+}

packages/BackupEncryption/test/robolectric/src/com/android/server/backup/encryption/kv/KeyValueListingBuilderTest.java

@@ -0,0 +1,110 @@
+/*
+ * 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.google.common.truth.Truth.assertThat;
+
+import static org.testng.Assert.assertThrows;
+
+import android.platform.test.annotations.Presubmit;
+
+import com.android.server.backup.encryption.chunk.ChunkHash;
+import com.android.server.backup.encryption.protos.nano.KeyValueListingProto;
+
+import com.google.common.collect.ImmutableMap;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+import java.util.Arrays;
+
+@RunWith(RobolectricTestRunner.class)
+@Presubmit
+public class KeyValueListingBuilderTest {
+    private static final String TEST_KEY_1 = "test_key_1";
+    private static final String TEST_KEY_2 = "test_key_2";
+    private static final ChunkHash TEST_HASH_1 =
+            new ChunkHash(Arrays.copyOf(new byte[] {1, 2}, ChunkHash.HASH_LENGTH_BYTES));
+    private static final ChunkHash TEST_HASH_2 =
+            new ChunkHash(Arrays.copyOf(new byte[] {5, 6}, ChunkHash.HASH_LENGTH_BYTES));
+
+    private KeyValueListingBuilder mBuilder;
+
+    @Before
+    public void setUp() {
+        mBuilder = new KeyValueListingBuilder();
+    }
+
+    @Test
+    public void addPair_nullKey_throws() {
+        assertThrows(NullPointerException.class, () -> mBuilder.addPair(null, TEST_HASH_1));
+    }
+
+    @Test
+    public void addPair_emptyKey_throws() {
+        assertThrows(IllegalArgumentException.class, () -> mBuilder.addPair("", TEST_HASH_1));
+    }
+
+    @Test
+    public void addPair_nullHash_throws() {
+        assertThrows(NullPointerException.class, () -> mBuilder.addPair(TEST_KEY_1, null));
+    }
+
+    @Test
+    public void build_noPairs_buildsEmptyListing() {
+        KeyValueListingProto.KeyValueListing listing = mBuilder.build();
+
+        assertThat(listing.entries).isEmpty();
+    }
+
+    @Test
+    public void build_returnsCorrectListing() {
+        mBuilder.addPair(TEST_KEY_1, TEST_HASH_1);
+
+        KeyValueListingProto.KeyValueListing listing = mBuilder.build();
+
+        assertThat(listing.entries.length).isEqualTo(1);
+        assertThat(listing.entries[0].key).isEqualTo(TEST_KEY_1);
+        assertThat(listing.entries[0].hash).isEqualTo(TEST_HASH_1.getHash());
+    }
+
+    @Test
+    public void addAll_addsAllPairsInMap() {
+        ImmutableMap<String, ChunkHash> pairs =
+                new ImmutableMap.Builder<String, ChunkHash>()
+                        .put(TEST_KEY_1, TEST_HASH_1)
+                        .put(TEST_KEY_2, TEST_HASH_2)
+                        .build();
+
+        mBuilder.addAll(pairs);
+        KeyValueListingProto.KeyValueListing listing = mBuilder.build();
+
+        assertThat(listing.entries.length).isEqualTo(2);
+        assertThat(listing.entries[0].key).isEqualTo(TEST_KEY_1);
+        assertThat(listing.entries[0].hash).isEqualTo(TEST_HASH_1.getHash());
+        assertThat(listing.entries[1].key).isEqualTo(TEST_KEY_2);
+        assertThat(listing.entries[1].hash).isEqualTo(TEST_HASH_2.getHash());
+    }
+
+    @Test
+    public void emptyListing_returnsListingWithoutAnyPairs() {
+        KeyValueListingProto.KeyValueListing emptyListing = KeyValueListingBuilder.emptyListing();
+        assertThat(emptyListing.entries).isEmpty();
+    }
+}