Merge "Implement RecoverableKeyStoreLoader loading keys into users' keystores" (09f48f31) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/locksettings/recoverablekeystore/RecoverableKeyStorage.java

+9 −0

Original line number	Diff line number	Diff line
		@@ -68,4 +68,13 @@ public interface RecoverableKeyStorage {
		SecretKey loadFromAndroidKeyStore(String alias) throws KeyStoreException,
		NoSuchAlgorithmException,
		UnrecoverableEntryException;

		/**
		* Removes the entry with the given {@code alias} from AndroidKeyStore.
		*
		* @throws KeyStoreException if an error occurred deleting the key from AndroidKeyStore.
		*
		* @hide
		*/
		void removeFromAndroidKeyStore(String alias) throws KeyStoreException;
		}

services/core/java/com/android/server/locksettings/recoverablekeystore/RecoverableKeyStorageImpl.java

+24 −18

Original line number	Diff line number	Diff line
		@@ -16,44 +16,40 @@

		package com.android.server.locksettings.recoverablekeystore;

		import android.security.keystore.AndroidKeyStoreProvider;
		import android.security.keystore.KeyProtection;

		import java.io.IOException;
		import java.security.KeyStore;
		import java.security.KeyStoreException;
		import java.security.NoSuchAlgorithmException;
		import java.security.NoSuchProviderException;
		import java.security.UnrecoverableEntryException;
		import java.security.cert.CertificateException;

		import javax.crypto.SecretKey;

		/**
		* Implementation of {@link RecoverableKeyStorage}.
		* Implementation of {@link RecoverableKeyStorage} for a specific application.
		*
		* <p>Persists wrapped keys to disk, and loads raw keys into AndroidKeyStore.
		*
		* @hide
		*/
		public class RecoverableKeyStorageImpl implements RecoverableKeyStorage {
		private static final String ANDROID_KEY_STORE_PROVIDER = "AndroidKeyStore";

		private final KeyStore mKeyStore;

		/**
		* A new instance.
		* A new instance, storing recoverable keys for the given {@code userId}.
		*
		* @throws KeyStoreException if unable to load AndroidKeyStore.
		* @throws NoSuchProviderException if AndroidKeyStore is not in this version of Android. Should
		* never occur.
		*
		* @hide
		*/
		public static RecoverableKeyStorageImpl newInstance() throws KeyStoreException {
		KeyStore keyStore = KeyStore.getInstance(ANDROID_KEY_STORE_PROVIDER);
		try {
		keyStore.load(/param=/ null);
		} catch (CertificateException \| IOException \| NoSuchAlgorithmException e) {
		// Should never happen.
		throw new KeyStoreException("Unable to load keystore.", e);
		}
		public static RecoverableKeyStorageImpl newInstance(int userId) throws KeyStoreException,
		NoSuchProviderException {
		KeyStore keyStore = AndroidKeyStoreProvider.getKeyStoreForUid(userId);
		return new RecoverableKeyStorageImpl(keyStore);
		}

		@@ -75,8 +71,7 @@ public class RecoverableKeyStorageImpl implements RecoverableKeyStorage {
		}

		/**
		* Imports {@code key} into AndroidKeyStore, keyed by the application's uid and the
		* {@code alias}.
		* Imports {@code key} into the application's AndroidKeyStore, keyed by {@code alias}.
		*
		* @param alias The alias of the key.
		* @param key The key.
		@@ -93,7 +88,7 @@ public class RecoverableKeyStorageImpl implements RecoverableKeyStorage {
		}

		/**
		* Loads a key handle from AndroidKeyStore.
		* Loads a key handle from the application's AndroidKeyStore.
		*
		* @param alias Alias of the key to load.
		* @return The key handle.
		@@ -104,7 +99,18 @@ public class RecoverableKeyStorageImpl implements RecoverableKeyStorage {
		@Override
		public SecretKey loadFromAndroidKeyStore(String alias)
		throws KeyStoreException, NoSuchAlgorithmException, UnrecoverableEntryException {
		return ((KeyStore.SecretKeyEntry) mKeyStore.getEntry(alias, /protParam=/ null))
		.getSecretKey();
		return ((SecretKey) mKeyStore.getKey(alias, /password=/ null));
		}

		/**
		* Removes the entry with the given {@code alias} from the application's AndroidKeyStore.
		*
		* @throws KeyStoreException if an error occurred deleting the key from AndroidKeyStore.
		*
		* @hide
		*/
		@Override
		public void removeFromAndroidKeyStore(String alias) throws KeyStoreException {
		mKeyStore.deleteEntry(alias);
		}
		}

services/tests/servicestests/src/com/android/server/locksettings/recoverablekeystore/RecoverableKeyStorageImplTest.java

0 → 100644

+155 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2017 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.locksettings.recoverablekeystore;

		import static org.junit.Assert.assertArrayEquals;
		import static org.junit.Assert.assertNull;
		import static org.junit.Assert.fail;

		import android.security.keystore.KeyProperties;
		import android.security.keystore.KeyProtection;
		import android.support.test.filters.SmallTest;
		import android.support.test.runner.AndroidJUnit4;

		import org.junit.After;
		import org.junit.Before;
		import org.junit.Test;
		import org.junit.runner.RunWith;

		import java.nio.charset.StandardCharsets;
		import java.security.InvalidKeyException;
		import java.security.KeyStoreException;
		import java.util.Random;

		import javax.crypto.Cipher;
		import javax.crypto.KeyGenerator;
		import javax.crypto.Mac;
		import javax.crypto.SecretKey;
		import javax.crypto.spec.GCMParameterSpec;

		@SmallTest
		@RunWith(AndroidJUnit4.class)
		public class RecoverableKeyStorageImplTest {
		private static final String KEY_ALGORITHM = "AES";
		private static final int GCM_TAG_LENGTH_BYTES = 16;
		private static final int BITS_PER_BYTE = 8;
		private static final int GCM_TAG_LENGTH_BITS = GCM_TAG_LENGTH_BYTES * BITS_PER_BYTE;
		private static final int GCM_NONCE_LENGTH_BYTES = 12;
		private static final String TEST_KEY_ALIAS = "RecoverableKeyStorageImplTestKey";
		private static final int KEYSTORE_UID_SELF = -1;

		private RecoverableKeyStorageImpl mRecoverableKeyStorage;

		@Before
		public void setUp() throws Exception {
		mRecoverableKeyStorage = RecoverableKeyStorageImpl.newInstance(
		/userId=/ KEYSTORE_UID_SELF);
		}

		@After
		public void tearDown() {
		try {
		mRecoverableKeyStorage.removeFromAndroidKeyStore(TEST_KEY_ALIAS);
		} catch (KeyStoreException e) {
		// Do nothing.
		}
		}

		@Test
		public void loadFromAndroidKeyStore_loadsAKeyThatWasImported() throws Exception {
		SecretKey key = generateKey();
		mRecoverableKeyStorage.importIntoAndroidKeyStore(
		TEST_KEY_ALIAS,
		key,
		getKeyProperties());

		assertKeysAreEquivalent(
		key, mRecoverableKeyStorage.loadFromAndroidKeyStore(TEST_KEY_ALIAS));
		}

		@Test
		public void importIntoAndroidKeyStore_importsWithKeyProperties() throws Exception {
		mRecoverableKeyStorage.importIntoAndroidKeyStore(
		TEST_KEY_ALIAS,
		generateKey(),
		getKeyProperties());

		SecretKey key = mRecoverableKeyStorage.loadFromAndroidKeyStore(TEST_KEY_ALIAS);

		Mac mac = Mac.getInstance("HmacSHA256");
		try {
		// Fails because missing PURPOSE_SIGN or PURPOSE_VERIFY
		mac.init(key);
		fail("Was able to initialize Mac with an ENCRYPT/DECRYPT-only key.");
		} catch (InvalidKeyException e) {
		// expect exception
		}
		}

		@Test
		public void removeFromAndroidKeyStore_removesAnEntry() throws Exception {
		mRecoverableKeyStorage.importIntoAndroidKeyStore(
		TEST_KEY_ALIAS,
		generateKey(),
		getKeyProperties());

		mRecoverableKeyStorage.removeFromAndroidKeyStore(TEST_KEY_ALIAS);

		assertNull(mRecoverableKeyStorage.loadFromAndroidKeyStore(TEST_KEY_ALIAS));
		}

		private static KeyProtection getKeyProperties() {
		return new KeyProtection.Builder(
		KeyProperties.PURPOSE_ENCRYPT \| KeyProperties.PURPOSE_DECRYPT)
		.setBlockModes(KeyProperties.BLOCK_MODE_GCM)
		.setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_NONE)
		.build();
		}

		/**
		* Asserts that {@code b} key can decrypt data encrypted with {@code a} key. Otherwise throws.
		*/
		private static void assertKeysAreEquivalent(SecretKey a, SecretKey b) throws Exception {
		byte[] plaintext = "doge".getBytes(StandardCharsets.UTF_8);
		byte[] nonce = generateGcmNonce();

		Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
		cipher.init(Cipher.ENCRYPT_MODE, a, new GCMParameterSpec(GCM_TAG_LENGTH_BITS, nonce));
		byte[] encrypted = cipher.doFinal(plaintext);

		cipher.init(Cipher.DECRYPT_MODE, b, new GCMParameterSpec(GCM_TAG_LENGTH_BITS, nonce));
		byte[] decrypted = cipher.doFinal(encrypted);

		assertArrayEquals(decrypted, plaintext);
		}

		/**
		* Returns a new random GCM nonce.
		*/
		private static byte[] generateGcmNonce() {
		Random random = new Random();
		byte[] nonce = new byte[GCM_NONCE_LENGTH_BYTES];
		random.nextBytes(nonce);
		return nonce;
		}

		private static SecretKey generateKey() throws Exception {
		KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_ALGORITHM);
		keyGenerator.init(/keySize=/ 256);
		return keyGenerator.generateKey();
		}
		}