app/src/main/java/com/stoutner/privacybrowser/activities/ImportExportActivity.java

   1 /*
   2  * Copyright © 2018-2019 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
   5  *
   6  * Privacy Browser is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * Privacy Browser is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 package com.stoutner.privacybrowser.activities;
  21
  22 import android.Manifest;
  23 import android.app.Activity;
  24 import android.content.Intent;
  25 import android.content.SharedPreferences;
  26 import android.content.pm.PackageManager;
  27 import android.media.MediaScannerConnection;
  28 import android.net.Uri;
  29 import android.os.Build;
  30 import android.os.Bundle;
  31 import android.os.Environment;
  32 import android.os.Handler;
  33 import android.preference.PreferenceManager;
  34 import android.provider.DocumentsContract;
  35 import android.text.Editable;
  36 import android.text.TextWatcher;
  37 import android.view.View;
  38 import android.view.WindowManager;
  39 import android.widget.AdapterView;
  40 import android.widget.ArrayAdapter;
  41 import android.widget.Button;
  42 import android.widget.EditText;
  43 import android.widget.LinearLayout;
  44 import android.widget.RadioButton;
  45 import android.widget.Spinner;
  46 import android.widget.TextView;
  47
  48 import androidx.annotation.NonNull;
  49 import androidx.appcompat.app.ActionBar;
  50 import androidx.appcompat.app.AppCompatActivity;
  51 import androidx.appcompat.widget.Toolbar;
  52 import androidx.cardview.widget.CardView;
  53 import androidx.core.app.ActivityCompat;
  54 import androidx.core.content.ContextCompat;
  55 import androidx.core.content.FileProvider;
  56 import androidx.fragment.app.DialogFragment;
  57
  58 import com.google.android.material.snackbar.Snackbar;
  59 import com.google.android.material.textfield.TextInputLayout;
  60
  61 import com.stoutner.privacybrowser.R;
  62 import com.stoutner.privacybrowser.dialogs.StoragePermissionDialog;
  63 import com.stoutner.privacybrowser.helpers.FileNameHelper;
  64 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  65
  66 import java.io.File;
  67 import java.io.FileInputStream;
  68 import java.io.FileOutputStream;
  69 import java.nio.charset.StandardCharsets;
  70 import java.security.MessageDigest;
  71 import java.security.SecureRandom;
  72 import java.util.Arrays;
  73
  74 import javax.crypto.Cipher;
  75 import javax.crypto.CipherInputStream;
  76 import javax.crypto.CipherOutputStream;
  77 import javax.crypto.spec.GCMParameterSpec;
  78 import javax.crypto.spec.SecretKeySpec;
  79
  80 public class ImportExportActivity extends AppCompatActivity implements StoragePermissionDialog.StoragePermissionDialogListener {
  81     // Create the encryption constants.
  82     private final int NO_ENCRYPTION = 0;
  83     private final int PASSWORD_ENCRYPTION = 1;
  84     private final int OPENPGP_ENCRYPTION = 2;
  85
  86     // Create the activity result constants.
  87     private final int BROWSE_RESULT_CODE = 0;
  88     private final int OPENPGP_EXPORT_RESULT_CODE = 1;
  89
  90     // `openKeychainInstalled` is accessed from an inner class.
  91     private boolean openKeychainInstalled;
  92
  93     @Override
  94     public void onCreate(Bundle savedInstanceState) {
  95         // Get a handle for the shared preferences.
  96         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
  97
  98         // Get the theme and screenshot preferences.
  99         boolean darkTheme = sharedPreferences.getBoolean("dark_theme", false);
 100         boolean allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);
 101
 102         // Disable screenshots if not allowed.
 103         if (!allowScreenshots) {
 104             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 105         }
 106
 107         // Set the activity theme.
 108         if (darkTheme) {
 109             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
 110         } else {
 111             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
 112         }
 113
 114         // Run the default commands.
 115         super.onCreate(savedInstanceState);
 116
 117         // Set the content view.
 118         setContentView(R.layout.import_export_coordinatorlayout);
 119
 120         // Set the support action bar.
 121         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 122         setSupportActionBar(toolbar);
 123
 124         // Get a handle for the action bar.
 125         ActionBar actionBar = getSupportActionBar();
 126
 127         // Remove the incorrect lint warning that the action bar might be null.
 128         assert actionBar != null;
 129
 130         // Display the home arrow on the support action bar.
 131         actionBar.setDisplayHomeAsUpEnabled(true);
 132
 133         // Find out if the system is running KitKat
 134         boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
 135
 136         // Find out if OpenKeychain is installed.
 137         try {
 138             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 139         } catch (PackageManager.NameNotFoundException exception) {
 140             openKeychainInstalled = false;
 141         }
 142
 143         // Get handles for the views that need to be modified.
 144         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 145         TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
 146         EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 147         TextView kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
 148         TextView openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 149         CardView fileLocationCardView = findViewById(R.id.file_location_cardview);
 150         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 151         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 152         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 153         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 154         TextView openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 155         Button importExportButton = findViewById(R.id.import_export_button);
 156         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 157
 158         // Create an array adapter for the spinner.
 159         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 160
 161         // Set the drop down view resource on the spinner.
 162         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 163
 164         // Set the array adapter for the spinner.
 165         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 166
 167         // Initially hide the unneeded views.
 168         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 169         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 170         openKeychainRequiredTextView.setVisibility(View.GONE);
 171         fileNameLinearLayout.setVisibility(View.GONE);
 172         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 173         importExportButton.setVisibility(View.GONE);
 174
 175         // Create strings for the default file paths.
 176         String defaultFilePath;
 177         String defaultPasswordEncryptionFilePath;
 178
 179         // Set the default file paths according to the storage permission status.
 180         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 181             // Set the default file paths to use the external public directory.
 182             defaultFilePath = Environment.getExternalStorageDirectory() + "/" + getString(R.string.settings_pbs);
 183             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 184         } else {  // The storage permission has not been granted.
 185             // Set the default file paths to use the external private directory.
 186             defaultFilePath = getApplicationContext().getExternalFilesDir(null) + "/" + getString(R.string.settings_pbs);
 187             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 188         }
 189
 190         // Set the default file path.
 191         fileNameEditText.setText(defaultFilePath);
 192
 193         // Display the encryption information when the spinner changes.
 194         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 195             @Override
 196             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 197                 switch (position) {
 198                     case NO_ENCRYPTION:
 199                         // Hide the unneeded layout items.
 200                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 201                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 202                         openKeychainRequiredTextView.setVisibility(View.GONE);
 203                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 204
 205                         // Show the file location card.
 206                         fileLocationCardView.setVisibility(View.VISIBLE);
 207
 208                         // Show the file name linear layout if either import or export is checked.
 209                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 210                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 211                         }
 212
 213                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 214                         if (importRadioButton.isChecked()) {
 215                             importExportButton.setText(R.string.import_button);
 216                         }
 217
 218                         // Reset the default file path.
 219                         fileNameEditText.setText(defaultFilePath);
 220
 221                         // Enable the import/export button if a file name exists.
 222                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 223                         break;
 224
 225                     case PASSWORD_ENCRYPTION:
 226                         if (runningKitKat) {
 227                             // Show the KitKat password encryption message.
 228                             kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
 229
 230                             // Hide the OpenPGP required text view and the file location card.
 231                             openKeychainRequiredTextView.setVisibility(View.GONE);
 232                             fileLocationCardView.setVisibility(View.GONE);
 233                         } else {
 234                             // Hide the OpenPGP layout items.
 235                             openKeychainRequiredTextView.setVisibility(View.GONE);
 236                             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 237
 238                             // Show the password encryption layout items.
 239                             passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
 240
 241                             // Show the file location card.
 242                             fileLocationCardView.setVisibility(View.VISIBLE);
 243
 244                             // Show the file name linear layout if either import or export is checked.
 245                             if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 246                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 247                             }
 248
 249                             // Reset the text of the import button, which may have been changed to `Decrypt`.
 250                             if (importRadioButton.isChecked()) {
 251                                 importExportButton.setText(R.string.import_button);
 252                             }
 253
 254                             // Update the default file path.
 255                             fileNameEditText.setText(defaultPasswordEncryptionFilePath);
 256
 257                             // Enable the import/export button if a password exists.
 258                             importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 259                         }
 260                         break;
 261
 262                     case OPENPGP_ENCRYPTION:
 263                         // Hide the password encryption layout items.
 264                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 265                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 266
 267                         // Updated items based on the installation status of OpenKeychain.
 268                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 269                             // Remove the default file path.
 270                             fileNameEditText.setText("");
 271
 272                             // Show the file location card.
 273                             fileLocationCardView.setVisibility(View.VISIBLE);
 274
 275                             if (importRadioButton.isChecked()) {
 276                                 // Show the file name linear layout and the OpenKeychain import instructions.
 277                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 278                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 279
 280                                 // Set the text of the import button to be `Decrypt`.
 281                                 importExportButton.setText(R.string.decrypt);
 282
 283                                 // Disable the import/export button.  The user needs to select a file to import first.
 284                                 importExportButton.setEnabled(false);
 285                             } else if (exportRadioButton.isChecked()) {
 286                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 287                                 fileNameLinearLayout.setVisibility(View.GONE);
 288                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 289
 290                                 // Enable the import/export button.
 291                                 importExportButton.setEnabled(true);
 292                             }
 293                         } else {  // OpenKeychain is not installed.
 294                             // Show the OpenPGP required layout item.
 295                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 296
 297                             // Hide the file location card.
 298                             fileLocationCardView.setVisibility(View.GONE);
 299                         }
 300                         break;
 301                 }
 302             }
 303
 304             @Override
 305             public void onNothingSelected(AdapterView<?> parent) {
 306
 307             }
 308         });
 309
 310         // Update the status of the import/export button when the password changes.
 311         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 312             @Override
 313             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 314                 // Do nothing.
 315             }
 316
 317             @Override
 318             public void onTextChanged(CharSequence s, int start, int before, int count) {
 319                 // Do nothing.
 320             }
 321
 322             @Override
 323             public void afterTextChanged(Editable s) {
 324                 // Enable the import/export button if a file name and password exists.
 325                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 326             }
 327         });
 328
 329         // Update the status of the import/export button when the file name EditText changes.
 330         fileNameEditText.addTextChangedListener(new TextWatcher() {
 331             @Override
 332             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 333                 // Do nothing.
 334             }
 335
 336             @Override
 337             public void onTextChanged(CharSequence s, int start, int before, int count) {
 338                 // Do nothing.
 339             }
 340
 341             @Override
 342             public void afterTextChanged(Editable s) {
 343                 // Adjust the export button according to the encryption spinner position.
 344                 switch (encryptionSpinner.getSelectedItemPosition()) {
 345                     case NO_ENCRYPTION:
 346                         // Enable the import/export button if a file name exists.
 347                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 348                         break;
 349
 350                     case PASSWORD_ENCRYPTION:
 351                         // Enable the import/export button if a file name and password exists.
 352                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 353                         break;
 354
 355                     case OPENPGP_ENCRYPTION:
 356                         // Enable the import/export button if OpenKeychain is installed and a file name exists.
 357                         importExportButton.setEnabled(openKeychainInstalled && !fileNameEditText.getText().toString().isEmpty());
 358                         break;
 359                 }
 360             }
 361         });
 362
 363         // Hide the storage permissions text view on API < 23 as permissions on older devices are automatically granted.
 364         if (Build.VERSION.SDK_INT < 23) {
 365             storagePermissionTextView.setVisibility(View.GONE);
 366         }
 367     }
 368
 369     public void onClickRadioButton(View view) {
 370         // Get handles for the views.
 371         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 372         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 373         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 374         TextView openKeychainImportInstructionTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 375         Button importExportButton = findViewById(R.id.import_export_button);
 376
 377         // Check to see if import or export was selected.
 378         switch (view.getId()) {
 379             case R.id.import_radiobutton:
 380                 // Check to see if OpenPGP encryption is selected.
 381                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 382                     // Show the OpenKeychain import instructions.
 383                     openKeychainImportInstructionTextView.setVisibility(View.VISIBLE);
 384
 385                     // Set the text on the import/export button to be `Decrypt`.
 386                     importExportButton.setText(R.string.decrypt);
 387
 388                     // Enable the decrypt button if there is a file name.
 389                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 390                 } else {  // OpenPGP encryption not selected.
 391                     // Hide the OpenKeychain import instructions.
 392                     openKeychainImportInstructionTextView.setVisibility(View.GONE);
 393
 394                     // Set the text on the import/export button to be `Import`.
 395                     importExportButton.setText(R.string.import_button);
 396                 }
 397
 398                 // Display the file name views.
 399                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 400                 importExportButton.setVisibility(View.VISIBLE);
 401                 break;
 402
 403             case R.id.export_radiobutton:
 404                 // Hide the OpenKeychain import instructions.
 405                 openKeychainImportInstructionTextView.setVisibility(View.GONE);
 406
 407                 // Set the text on the import/export button to be `Export`.
 408                 importExportButton.setText(R.string.export);
 409
 410                 // Show the import/export button.
 411                 importExportButton.setVisibility(View.VISIBLE);
 412
 413                 // Check to see if OpenPGP encryption is selected.
 414                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 415                     // Hide the file name views.
 416                     fileNameLinearLayout.setVisibility(View.GONE);
 417
 418                     // Enable the export button.
 419                     importExportButton.setEnabled(true);
 420                 } else {  // OpenPGP encryption is not selected.
 421                     // Show the file name views.
 422                     fileNameLinearLayout.setVisibility(View.VISIBLE);
 423                 }
 424                 break;
 425         }
 426     }
 427
 428     public void browse(View view) {
 429         // Get a handle for the import radiobutton.
 430         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 431
 432         // Check to see if import or export is selected.
 433         if (importRadioButton.isChecked()) {  // Import is selected.
 434             // Create the file picker intent.
 435             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 436
 437             // Set the intent MIME type to include all files so that everything is visible.
 438             importBrowseIntent.setType("*/*");
 439
 440             // Set the initial directory if the minimum API >= 26.
 441             if (Build.VERSION.SDK_INT >= 26) {
 442                 importBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 443             }
 444
 445             // Request a file that can be opened.
 446             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 447
 448             // Launch the file picker.
 449             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 450         } else {  // Export is selected
 451             // Create the file picker intent.
 452             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 453
 454             // Set the intent MIME type to include all files so that everything is visible.
 455             exportBrowseIntent.setType("*/*");
 456
 457             // Set the initial export file name.
 458             exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_pbs));
 459
 460             // Set the initial directory if the minimum API >= 26.
 461             if (Build.VERSION.SDK_INT >= 26) {
 462                 exportBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 463             }
 464
 465             // Request a file that can be opened.
 466             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 467
 468             // Launch the file picker.
 469             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 470         }
 471     }
 472
 473     public void importExport(View view) {
 474         // Get a handle for the views.
 475         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 476         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 477         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 478
 479         // Check to see if the storage permission is needed.
 480         if ((encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) && exportRadioButton.isChecked()) {  // Permission not needed to export via OpenKeychain.
 481             // Export the settings.
 482             exportSettings();
 483         } else if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 484             // Check to see if import or export is selected.
 485             if (importRadioButton.isChecked()) {  // Import is selected.
 486                 // Import the settings.
 487                 importSettings();
 488             } else {  // Export is selected.
 489                 // Export the settings.
 490                 exportSettings();
 491             }
 492         } else {  // The storage permission has not been granted.
 493             // Get a handle for the file name EditText.
 494             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 495
 496             // Get the file name string.
 497             String fileNameString = fileNameEditText.getText().toString();
 498
 499             // Get the external private directory `File`.
 500             File externalPrivateDirectoryFile = getExternalFilesDir(null);
 501
 502             // Remove the incorrect lint error below that the file might be null.
 503             assert externalPrivateDirectoryFile != null;
 504
 505             // Get the external private directory string.
 506             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 507
 508             // Check to see if the file path is in the external private directory.
 509             if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
 510                 // Check to see if import or export is selected.
 511                 if (importRadioButton.isChecked()) {  // Import is selected.
 512                     // Import the settings.
 513                     importSettings();
 514                 } else {  // Export is selected.
 515                     // Export the settings.
 516                     exportSettings();
 517                 }
 518             } else {  // The file path is in a public directory.
 519                 // Check if the user has previously denied the storage permission.
 520                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
 521                     // Instantiate the storage permission alert dialog.
 522                     DialogFragment storagePermissionDialogFragment = StoragePermissionDialog.displayDialog(0);
 523
 524                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
 525                     storagePermissionDialogFragment.show(getSupportFragmentManager(), getString(R.string.storage_permission));
 526                 } else {  // Show the permission request directly.
 527                     // Request the storage permission.  The export will be run when it finishes.
 528                     ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 529                 }
 530             }
 531         }
 532     }
 533
 534     @Override
 535     public void onCloseStoragePermissionDialog(int type) {
 536         // Request the write external storage permission.  The import/export will be run when it finishes.
 537         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 538     }
 539
 540     @Override
 541     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 542         // Get a handle for the import radiobutton.
 543         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 544
 545         // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 546         if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 547             // Run the import or export methods according to which radio button is selected.
 548             if (importRadioButton.isChecked()) {  // Import is selected.
 549                 // Import the settings.
 550                 importSettings();
 551             } else {  // Export is selected.
 552                 // Export the settings.
 553                 exportSettings();
 554             }
 555         } else {  // The storage permission was not granted.
 556             // Display an error snackbar.
 557             Snackbar.make(importRadioButton, getString(R.string.cannot_use_location), Snackbar.LENGTH_LONG).show();
 558         }
 559     }
 560
 561     @Override
 562     public void onActivityResult(int requestCode, int resultCode, Intent intent) {
 563         // Run the default commands.
 564         super.onActivityResult(requestCode, resultCode, intent);
 565
 566         switch (requestCode) {
 567             case (BROWSE_RESULT_CODE):
 568                 // Don't do anything if the user pressed back from the file picker.
 569                 if (resultCode == Activity.RESULT_OK) {
 570                     // Get a handle for the file name edit text.
 571                     EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 572
 573                     // Instantiate the file name helper.
 574                     FileNameHelper fileNameHelper = new FileNameHelper();
 575
 576                     // Get the file path URI from the intent.
 577                     Uri filePathUri = intent.getData();
 578
 579                     // Use the file path from the intent if it exists.
 580                     if (filePathUri != null) {
 581                         // Convert the file name URI to a file name path.
 582                         String fileNamePath = fileNameHelper.convertUriToFileNamePath(filePathUri);
 583
 584                         // Set the file name path as the text of the file name edit text.
 585                         fileNameEditText.setText(fileNamePath);
 586                     }
 587                 }
 588                 break;
 589
 590             case OPENPGP_EXPORT_RESULT_CODE:
 591                 // Get the temporary unencrypted export file.
 592                 File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 593
 594                 // Delete the temporary unencrypted export file if it exists.
 595                 if (temporaryUnencryptedExportFile.exists()) {
 596                     //noinspection ResultOfMethodCallIgnored
 597                     temporaryUnencryptedExportFile.delete();
 598                 }
 599                 break;
 600         }
 601     }
 602
 603     private void exportSettings() {
 604         // Get a handle for the views.
 605         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 606         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 607
 608         // Instantiate the import export database helper.
 609         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 610
 611         // Get the export file string.
 612         String exportFileString = fileNameEditText.getText().toString();
 613
 614         // Get the export and temporary unencrypted export files.
 615         File exportFile = new File(exportFileString);
 616         File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 617
 618         // Create an export status string.
 619         String exportStatus;
 620
 621         // Export according to the encryption type.
 622         switch (encryptionSpinner.getSelectedItemPosition()) {
 623             case NO_ENCRYPTION:
 624                 // Export the unencrypted file.
 625                 exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
 626
 627                 // Show a disposition snackbar.
 628                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 629                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 630                 } else {
 631                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 632                 }
 633                 break;
 634
 635             case PASSWORD_ENCRYPTION:
 636                 // Create an unencrypted export in a private directory.
 637                 exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 638
 639                 try {
 640                     // Create an unencrypted export file input stream.
 641                     FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 642
 643                     // Delete the encrypted export file if it exists.
 644                     if (exportFile.exists()) {
 645                         //noinspection ResultOfMethodCallIgnored
 646                         exportFile.delete();
 647                     }
 648
 649                     // Create an encrypted export file output stream.
 650                     FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 651
 652                     // Get a handle for the encryption password EditText.
 653                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 654
 655                     // Get the encryption password.
 656                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 657
 658                     // Initialize a secure random number generator.
 659                     SecureRandom secureRandom = new SecureRandom();
 660
 661                     // Get a 256 bit (32 byte) random salt.
 662                     byte[] saltByteArray = new byte[32];
 663                     secureRandom.nextBytes(saltByteArray);
 664
 665                     // Convert the encryption password to a byte array.
 666                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 667
 668                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 669                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 670                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 671                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 672
 673                     // Get a SHA-512 message digest.
 674                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 675
 676                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 677                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 678
 679                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 680                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 681
 682                     // Create an AES secret key from the encryption password byte array.
 683                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 684
 685                     // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 686                     byte[] initializationVector = new byte[12];
 687                     secureRandom.nextBytes(initializationVector);
 688
 689                     // Get a Advanced Encryption Standard, Galois/Counter Mode, No Padding cipher instance. Galois/Counter mode protects against modification of the ciphertext.  It doesn't use padding.
 690                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 691
 692                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 693                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 694
 695                     // Initialize the cipher.
 696                     cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 697
 698                     // Add the salt and the initialization vector to the export file.
 699                     encryptedExportFileOutputStream.write(saltByteArray);
 700                     encryptedExportFileOutputStream.write(initializationVector);
 701
 702                     // Create a cipher output stream.
 703                     CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
 704
 705                     // Initialize variables to store data as it is moved from the unencrypted export file input stream to the cipher output stream.  Move 128 bits (16 bytes) at a time.
 706                     int numberOfBytesRead;
 707                     byte[] encryptedBytes = new byte[16];
 708
 709                     // Read up to 128 bits (16 bytes) of data from the unencrypted export file stream.  `-1` will be returned when the end of the file is reached.
 710                     while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 711                         // Write the data to the cipher output stream.
 712                         cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 713                     }
 714
 715                     // Close the streams.
 716                     cipherOutputStream.flush();
 717                     cipherOutputStream.close();
 718                     encryptedExportFileOutputStream.close();
 719                     unencryptedExportFileInputStream.close();
 720
 721                     // Wipe the encryption data from memory.
 722                     //noinspection UnusedAssignment
 723                     encryptionPasswordString = "";
 724                     Arrays.fill(saltByteArray, (byte) 0);
 725                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 726                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 727                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 728                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 729                     Arrays.fill(initializationVector, (byte) 0);
 730                     Arrays.fill(encryptedBytes, (byte) 0);
 731
 732                     // Delete the temporary unencrypted export file.
 733                     //noinspection ResultOfMethodCallIgnored
 734                     temporaryUnencryptedExportFile.delete();
 735                 } catch (Exception exception) {
 736                     exportStatus = exception.toString();
 737                 }
 738
 739                 // Show a disposition snackbar.
 740                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 741                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 742                 } else {
 743                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 744                 }
 745                 break;
 746
 747             case OPENPGP_ENCRYPTION:
 748                 // Create an unencrypted export in the private location.
 749                 importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 750
 751                 // Create an encryption intent for OpenKeychain.
 752                 Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 753
 754                 // Include the temporary unencrypted export file URI.
 755                 openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryUnencryptedExportFile));
 756
 757                 // Allow OpenKeychain to read the file URI.
 758                 openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 759
 760                 // Send the intent to the OpenKeychain package.
 761                 openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 762
 763                 // Make it so.
 764                 startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 765                 break;
 766         }
 767
 768         // Add the file to the list of recent files.  This doesn't currently work, but maybe it will someday.
 769         MediaScannerConnection.scanFile(this, new String[] {exportFileString}, new String[] {"application/x-sqlite3"}, null);
 770     }
 771
 772     private void importSettings() {
 773         // Get a handle for the views.
 774         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 775         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 776
 777         // Instantiate the import export database helper.
 778         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 779
 780         // Get the import file.
 781         File importFile = new File(fileNameEditText.getText().toString());
 782
 783         // Initialize the import status string
 784         String importStatus = "";
 785
 786         // Import according to the encryption type.
 787         switch (encryptionSpinner.getSelectedItemPosition()) {
 788             case NO_ENCRYPTION:
 789                 // Import the unencrypted file.
 790                 importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
 791                 break;
 792
 793             case PASSWORD_ENCRYPTION:
 794                 // Use a private temporary import location.
 795                 File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 796
 797                 try {
 798                     // Create an encrypted import file input stream.
 799                     FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 800
 801                     // Delete the temporary import file if it exists.
 802                     if (temporaryUnencryptedImportFile.exists()) {
 803                         //noinspection ResultOfMethodCallIgnored
 804                         temporaryUnencryptedImportFile.delete();
 805                     }
 806
 807                     // Create an unencrypted import file output stream.
 808                     FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 809
 810                     // Get a handle for the encryption password EditText.
 811                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 812
 813                     // Get the encryption password.
 814                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 815
 816                     // Get the salt from the beginning of the import file.
 817                     byte[] saltByteArray = new byte[32];
 818                     //noinspection ResultOfMethodCallIgnored
 819                     encryptedImportFileInputStream.read(saltByteArray);
 820
 821                     // Get the initialization vector from the import file.
 822                     byte[] initializationVector = new byte[12];
 823                     //noinspection ResultOfMethodCallIgnored
 824                     encryptedImportFileInputStream.read(initializationVector);
 825
 826                     // Convert the encryption password to a byte array.
 827                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 828
 829                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 830                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 831                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 832                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 833
 834                     // Get a SHA-512 message digest.
 835                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 836
 837                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 838                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 839
 840                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 841                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 842
 843                     // Create an AES secret key from the encryption password byte array.
 844                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 845
 846                     // Get a Advanced Encryption Standard, Galois/Counter Mode, No Padding cipher instance. Galois/Counter mode protects against modification of the ciphertext.  It doesn't use padding.
 847                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 848
 849                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 850                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 851
 852                     // Initialize the cipher.
 853                     cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 854
 855                     // Create a cipher input stream.
 856                     CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
 857
 858                     // Initialize variables to store data as it is moved from the cipher input stream to the unencrypted import file output stream.  Move 128 bits (16 bytes) at a time.
 859                     int numberOfBytesRead;
 860                     byte[] decryptedBytes = new byte[16];
 861
 862                     // Read up to 128 bits (16 bytes) of data from the cipher input stream.  `-1` will be returned when the end fo the file is reached.
 863                     while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 864                         // Write the data to the unencrypted import file output stream.
 865                         unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 866                     }
 867
 868                     // Close the streams.
 869                     unencryptedImportFileOutputStream.flush();
 870                     unencryptedImportFileOutputStream.close();
 871                     cipherInputStream.close();
 872                     encryptedImportFileInputStream.close();
 873
 874                     // Wipe the encryption data from memory.
 875                     //noinspection UnusedAssignment
 876                     encryptionPasswordString = "";
 877                     Arrays.fill(saltByteArray, (byte) 0);
 878                     Arrays.fill(initializationVector, (byte) 0);
 879                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 880                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 881                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 882                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 883                     Arrays.fill(decryptedBytes, (byte) 0);
 884
 885                     // Import the unencrypted database from the private location.
 886                     importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
 887
 888                     // Delete the temporary unencrypted import file.
 889                     //noinspection ResultOfMethodCallIgnored
 890                     temporaryUnencryptedImportFile.delete();
 891                 } catch (Exception exception) {
 892                     importStatus = exception.toString();
 893                 }
 894                 break;
 895
 896             case OPENPGP_ENCRYPTION:
 897                 try {
 898                     // Create an decryption intent for OpenKeychain.
 899                     Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 900
 901                     // Include the URI to be decrypted.
 902                     openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), importFile));
 903
 904                     // Allow OpenKeychain to read the file URI.
 905                     openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 906
 907                     // Send the intent to the OpenKeychain package.
 908                     openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 909
 910                     // Make it so.
 911                     startActivity(openKeychainDecryptIntent);
 912                 } catch (IllegalArgumentException exception) {  // The file import location is not valid.
 913                     // Display a snack bar with the import error.
 914                     Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + exception.toString(), Snackbar.LENGTH_INDEFINITE).show();
 915                 }
 916                 break;
 917         }
 918
 919         // Respond to the import disposition.
 920         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
 921             // Create an intent to restart Privacy Browser.
 922             Intent restartIntent = getParentActivityIntent();
 923
 924             // Assert that the intent is not null to remove the lint error below.
 925             assert restartIntent != null;
 926
 927             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 928             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 929
 930             // Create a restart handler.
 931             Handler restartHandler = new Handler();
 932
 933             // Create a restart runnable.
 934             Runnable restartRunnable =  () -> {
 935                 // Restart Privacy Browser.
 936                 startActivity(restartIntent);
 937
 938                 // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
 939                 System.exit(0);
 940             };
 941
 942             // Restart Privacy Browser after 150 milliseconds to allow enough time for the preferences to be saved.
 943             restartHandler.postDelayed(restartRunnable, 150);
 944
 945         } else if (!(encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION)){  // The import was not successful.
 946             // Display a snack bar with the import error.
 947             Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 948         }
 949     }
 950 }