Import InitializeRecoverableSecondaryKeyTask

/*

 * 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.content.Context;

import android.security.keystore.recovery.InternalRecoveryServiceException;

import android.security.keystore.recovery.LockScreenRequiredException;

import android.security.keystore.recovery.RecoveryController;

import android.util.Slog;

import com.android.server.backup.encryption.CryptoSettings;

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 java.security.InvalidKeyException;

import java.security.UnrecoverableKeyException;

import java.util.Collections;

import java.util.Optional;

/**

 * Initializes the device for encrypted backup, through generating a secondary key, and setting its

 * alias in the settings.

 *

 * <p>If the device is already initialized, this is a no-op.

 */

public class InitializeRecoverableSecondaryKeyTask {

    private static final String TAG = "InitializeRecoverableSecondaryKeyTask";

    private final Context mContext;

    private final CryptoSettings mCryptoSettings;

    private final RecoverableKeyStoreSecondaryKeyManager mSecondaryKeyManager;

    private final CryptoBackupServer mBackupServer;

    /**

     * A new instance.

     *

     * @param cryptoSettings Settings to store the active key alias.

     * @param secondaryKeyManager Key manager to generate the new active secondary key.

     * @param backupServer Server with which to sync the active key alias.

     */

    public InitializeRecoverableSecondaryKeyTask(

            Context context,

            CryptoSettings cryptoSettings,

            RecoverableKeyStoreSecondaryKeyManager secondaryKeyManager,

            CryptoBackupServer backupServer) {

        mContext = context;

        mCryptoSettings = cryptoSettings;

        mSecondaryKeyManager = secondaryKeyManager;

        mBackupServer = backupServer;

    }

    /**

     * Initializes the device for encrypted backup, by generating a recoverable secondary key, then

     * sending that alias to the backup server and saving it in local settings.

     *

     * <p>If there is already an active secondary key then does nothing. If the active secondary key

     * is destroyed then throws {@link InvalidKeyException}.

     *

     * <p>If a key rotation is pending and able to finish (i.e., the new key has synced with the

     * remote trusted hardware module), then it completes the rotation before returning the key.

     *

     * @return The active secondary key.

     * @throws InvalidKeyException if the secondary key is in a bad state.

     */

    public RecoverableKeyStoreSecondaryKey run()

            throws InvalidKeyException, LockScreenRequiredException, UnrecoverableKeyException,

                    InternalRecoveryServiceException {

        // Complete any pending key rotations

        new RotateSecondaryKeyTask(

                        mContext,

                        mSecondaryKeyManager,

                        mBackupServer,

                        mCryptoSettings,

                        RecoveryController.getInstance(mContext))

                .run();

        return runInternal();

    }

    private RecoverableKeyStoreSecondaryKey runInternal()

            throws InvalidKeyException, LockScreenRequiredException, UnrecoverableKeyException,

                    InternalRecoveryServiceException {

        Optional<RecoverableKeyStoreSecondaryKey> maybeActiveKey = loadFromSetting();

        if (maybeActiveKey.isPresent()) {

            assertKeyNotDestroyed(maybeActiveKey.get());

            Slog.d(TAG, "Secondary key already initialized: " + maybeActiveKey.get().getAlias());

            return maybeActiveKey.get();

        }

        Slog.v(TAG, "Initializing for crypto: generating a secondary key.");

        RecoverableKeyStoreSecondaryKey key = mSecondaryKeyManager.generate();

        String alias = key.getAlias();

        Slog.i(TAG, "Generated new secondary key " + alias);

        // No tertiary keys yet as we are creating a brand new secondary (without rotation).

        mBackupServer.setActiveSecondaryKeyAlias(alias, /*tertiaryKeys=*/ Collections.emptyMap());

        Slog.v(TAG, "Successfully synced %s " + alias + " with server.");

        mCryptoSettings.initializeWithKeyAlias(alias);

        Slog.v(TAG, "Successfully saved " + alias + " as active secondary to disk.");

        return key;

    }

    private void assertKeyNotDestroyed(RecoverableKeyStoreSecondaryKey key)

            throws InvalidKeyException {

        if (key.getStatus(mContext) == RecoverableKeyStoreSecondaryKey.Status.DESTROYED) {

            throw new InvalidKeyException("Key destroyed: " + key.getAlias());

        }

    }

    private Optional<RecoverableKeyStoreSecondaryKey> loadFromSetting()

            throws InvalidKeyException, UnrecoverableKeyException,

                    InternalRecoveryServiceException {

        // TODO: b/141856950.

        if (!mCryptoSettings.getIsInitialized()) {

            return Optional.empty();

        }

        Optional<String> maybeAlias = mCryptoSettings.getActiveSecondaryKeyAlias();

        if (!maybeAlias.isPresent()) {

            throw new InvalidKeyException(

                    "Settings said crypto was initialized, but there was no active secondary"

                            + " alias");

        }

        String alias = maybeAlias.get();

        Optional<RecoverableKeyStoreSecondaryKey> key;

        key = mSecondaryKeyManager.get(alias);

        if (!key.isPresent()) {

            throw new InvalidKeyException(

                    "Initialized with key but it was not in key store: " + alias);

        }

        return key;

    }

}

/*

 * 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 android.security.keystore.recovery.RecoveryController.RECOVERY_STATUS_PERMANENT_FAILURE;

import static com.google.common.truth.Truth.assertThat;

import static org.mockito.ArgumentMatchers.any;

import static org.mockito.Mockito.doThrow;

import static org.mockito.Mockito.when;

import static org.testng.Assert.assertThrows;

import android.app.Application;

import android.security.keystore.recovery.RecoveryController;

import androidx.test.core.app.ApplicationProvider;

import com.android.server.backup.encryption.CryptoSettings;

import com.android.server.backup.encryption.keys.RecoverableKeyStoreSecondaryKey;

import com.android.server.backup.encryption.keys.RecoverableKeyStoreSecondaryKeyManager;

import com.android.server.testing.fakes.FakeCryptoBackupServer;

import com.android.server.testing.shadows.ShadowRecoveryController;

import java.security.InvalidKeyException;

import java.security.SecureRandom;

import java.util.Optional;

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 org.robolectric.annotation.Config;

@Config(shadows = {ShadowRecoveryController.class})

@RunWith(RobolectricTestRunner.class)

public class InitializeRecoverableSecondaryKeyTaskTest {

    @Mock private CryptoSettings mMockCryptoSettings;

    private Application mApplication;

    private InitializeRecoverableSecondaryKeyTask mTask;

    private CryptoSettings mCryptoSettings;

    private FakeCryptoBackupServer mFakeCryptoBackupServer;

    private RecoverableKeyStoreSecondaryKeyManager mSecondaryKeyManager;

    @Before

    public void setUp() throws Exception {

        MockitoAnnotations.initMocks(this);

        ShadowRecoveryController.reset();

        mApplication = ApplicationProvider.getApplicationContext();

        mFakeCryptoBackupServer = new FakeCryptoBackupServer();

        mCryptoSettings = CryptoSettings.getInstanceForTesting(mApplication);

        mSecondaryKeyManager =

                new RecoverableKeyStoreSecondaryKeyManager(

                        RecoveryController.getInstance(mApplication), new SecureRandom());

        mTask =

                new InitializeRecoverableSecondaryKeyTask(

                        mApplication, mCryptoSettings, mSecondaryKeyManager, mFakeCryptoBackupServer);

    }

    @Test

    public void testRun_generatesNewKeyInRecoveryController() throws Exception {

        RecoverableKeyStoreSecondaryKey key = mTask.run();

        assertThat(RecoveryController.getInstance(mApplication).getAliases())

                .contains(key.getAlias());

    }

    @Test

    public void testRun_setsAliasOnServer() throws Exception {

        RecoverableKeyStoreSecondaryKey key = mTask.run();

        assertThat(mFakeCryptoBackupServer.getActiveSecondaryKeyAlias().get())

                .isEqualTo(key.getAlias());

    }

    @Test

    public void testRun_setsAliasInSettings() throws Exception {

        RecoverableKeyStoreSecondaryKey key = mTask.run();

        assertThat(mCryptoSettings.getActiveSecondaryKeyAlias().get()).isEqualTo(key.getAlias());

    }

    @Test

    public void testRun_initializesSettings() throws Exception {

        mTask.run();

        assertThat(mCryptoSettings.getIsInitialized()).isTrue();

    }

    @Test

    public void testRun_initializeSettingsFails_throws() throws Exception {

        useMockCryptoSettings();

        doThrow(IllegalArgumentException.class)

                .when(mMockCryptoSettings)

                .initializeWithKeyAlias(any());

        assertThrows(IllegalArgumentException.class, () -> mTask.run());

    }

    @Test

    public void testRun_doesNotGenerateANewKeyIfOneIsAvailable() throws Exception {

        RecoverableKeyStoreSecondaryKey key1 = mTask.run();

        RecoverableKeyStoreSecondaryKey key2 = mTask.run();

        assertThat(key1.getAlias()).isEqualTo(key2.getAlias());

        assertThat(key2.getSecretKey()).isEqualTo(key2.getSecretKey());

    }

    @Test

    public void testRun_existingKeyButDestroyed_throws() throws Exception {

        RecoverableKeyStoreSecondaryKey key = mTask.run();

        ShadowRecoveryController.setRecoveryStatus(

                key.getAlias(), RECOVERY_STATUS_PERMANENT_FAILURE);

        assertThrows(InvalidKeyException.class, () -> mTask.run());

    }

    @Test

    public void testRun_settingsInitializedButNotSecondaryKeyAlias_throws() {

        useMockCryptoSettings();

        when(mMockCryptoSettings.getIsInitialized()).thenReturn(true);

        when(mMockCryptoSettings.getActiveSecondaryKeyAlias()).thenReturn(Optional.empty());

        assertThrows(InvalidKeyException.class, () -> mTask.run());

    }

    @Test

    public void testRun_keyAliasSetButNotInStore_throws() {

        useMockCryptoSettings();

        when(mMockCryptoSettings.getIsInitialized()).thenReturn(true);

        when(mMockCryptoSettings.getActiveSecondaryKeyAlias())

                .thenReturn(Optional.of("missingAlias"));

        assertThrows(InvalidKeyException.class, () -> mTask.run());

    }

    private void useMockCryptoSettings() {

        mTask =

                new InitializeRecoverableSecondaryKeyTask(

                        mApplication,

                        mMockCryptoSettings,

                        mSecondaryKeyManager,

                        mFakeCryptoBackupServer);

    }

}