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.ImportExportDatabaseHelper;
  64
  65 import java.io.File;
  66 import java.io.FileInputStream;
  67 import java.io.FileOutputStream;
  68 import java.nio.charset.StandardCharsets;
  69 import java.security.MessageDigest;
  70 import java.security.SecureRandom;
  71 import java.util.Arrays;
  72
  73 import javax.crypto.Cipher;
  74 import javax.crypto.CipherInputStream;
  75 import javax.crypto.CipherOutputStream;
  76 import javax.crypto.spec.GCMParameterSpec;
  77 import javax.crypto.spec.SecretKeySpec;
  78
  79 public class ImportExportActivity extends AppCompatActivity implements StoragePermissionDialog.StoragePermissionDialogListener {
  80     // Create the encryption constants.
  81     private final int NO_ENCRYPTION = 0;
  82     private final int PASSWORD_ENCRYPTION = 1;
  83     private final int OPENPGP_ENCRYPTION = 2;
  84
  85     // Create the activity result constants.
  86     private final int BROWSE_RESULT_CODE = 0;
  87     private final int OPENPGP_EXPORT_RESULT_CODE = 1;
  88
  89     // `openKeychainInstalled` is accessed from an inner class.
  90     private boolean openKeychainInstalled;
  91
  92     @Override
  93     public void onCreate(Bundle savedInstanceState) {
  94         // Get a handle for the shared preferences.
  95         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
  96
  97         // Get the theme and screenshot preferences.
  98         boolean darkTheme = sharedPreferences.getBoolean("dark_theme", false);
  99         boolean allowScreenshots = sharedPreferences.getBoolean("allow_screenshots", false);
 100
 101         // Disable screenshots if not allowed.
 102         if (!allowScreenshots) {
 103             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 104         }
 105
 106         // Set the activity theme.
 107         if (darkTheme) {
 108             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
 109         } else {
 110             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
 111         }
 112
 113         // Run the default commands.
 114         super.onCreate(savedInstanceState);
 115
 116         // Set the content view.
 117         setContentView(R.layout.import_export_coordinatorlayout);
 118
 119         // Use the `SupportActionBar` from `android.support.v7.app.ActionBar` until the minimum API is >= 21.
 120         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 121         setSupportActionBar(toolbar);
 122
 123         // Get a handle for the action bar.
 124         ActionBar actionBar = getSupportActionBar();
 125
 126         // Remove the incorrect lint warning that the action bar might be null.
 127         assert actionBar != null;
 128
 129         // Display the home arrow on the support action bar.
 130         actionBar.setDisplayHomeAsUpEnabled(true);
 131
 132         // Find out if we are running KitKat
 133         boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
 134
 135         // Find out if OpenKeychain is installed.
 136         try {
 137             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 138         } catch (PackageManager.NameNotFoundException exception) {
 139             openKeychainInstalled = false;
 140         }
 141
 142         // Get handles for the views that need to be modified.
 143         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 144         TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
 145         EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 146         TextView kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
 147         TextView openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 148         CardView fileLocationCardView = findViewById(R.id.file_location_cardview);
 149         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 150         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 151         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 152         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 153         TextView openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 154         Button importExportButton = findViewById(R.id.import_export_button);
 155         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 156
 157         // Create an array adapter for the spinner.
 158         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 159
 160         // Set the drop down view resource on the spinner.
 161         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 162
 163         // Set the array adapter for the spinner.
 164         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 165
 166         // Initially hide the unneeded views.
 167         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 168         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 169         openKeychainRequiredTextView.setVisibility(View.GONE);
 170         fileNameLinearLayout.setVisibility(View.GONE);
 171         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 172         importExportButton.setVisibility(View.GONE);
 173
 174         // Create strings for the default file paths.
 175         String defaultFilePath;
 176         String defaultPasswordEncryptionFilePath;
 177
 178         // Set the default file paths according to the storage permission status.
 179         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 180             // Set the default file paths to use the external public directory.
 181             defaultFilePath = Environment.getExternalStorageDirectory() + "/" + getString(R.string.settings_pbs);
 182             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 183         } else {  // The storage permission has not been granted.
 184             // Set the default file paths to use the external private directory.
 185             defaultFilePath = getApplicationContext().getExternalFilesDir(null) + "/" + getString(R.string.settings_pbs);
 186             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 187         }
 188
 189         // Set the default file path.
 190         fileNameEditText.setText(defaultFilePath);
 191
 192         // Display the encryption information when the spinner changes.
 193         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 194             @Override
 195             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 196                 switch (position) {
 197                     case NO_ENCRYPTION:
 198                         // Hide the unneeded layout items.
 199                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 200                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 201                         openKeychainRequiredTextView.setVisibility(View.GONE);
 202                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 203
 204                         // Show the file location card.
 205                         fileLocationCardView.setVisibility(View.VISIBLE);
 206
 207                         // Show the file name linear layout if either import or export is checked.
 208                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 209                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 210                         }
 211
 212                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 213                         if (importRadioButton.isChecked()) {
 214                             importExportButton.setText(R.string.import_button);
 215                         }
 216
 217                         // Reset the default file path.
 218                         fileNameEditText.setText(defaultFilePath);
 219
 220                         // Enable the import/export button if a file name exists.
 221                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 222                         break;
 223
 224                     case PASSWORD_ENCRYPTION:
 225                         if (runningKitKat) {
 226                             // Show the KitKat password encryption message.
 227                             kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
 228
 229                             // Hide the OpenPGP required text view and the file location card.
 230                             openKeychainRequiredTextView.setVisibility(View.GONE);
 231                             fileLocationCardView.setVisibility(View.GONE);
 232                         } else {
 233                             // Hide the OpenPGP layout items.
 234                             openKeychainRequiredTextView.setVisibility(View.GONE);
 235                             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 236
 237                             // Show the password encryption layout items.
 238                             passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
 239
 240                             // Show the file location card.
 241                             fileLocationCardView.setVisibility(View.VISIBLE);
 242
 243                             // Show the file name linear layout if either import or export is checked.
 244                             if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 245                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 246                             }
 247
 248                             // Reset the text of the import button, which may have been changed to `Decrypt`.
 249                             if (importRadioButton.isChecked()) {
 250                                 importExportButton.setText(R.string.import_button);
 251                             }
 252
 253                             // Update the default file path.
 254                             fileNameEditText.setText(defaultPasswordEncryptionFilePath);
 255
 256                             // Enable the import/export button if a password exists.
 257                             importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 258                         }
 259                         break;
 260
 261                     case OPENPGP_ENCRYPTION:
 262                         // Hide the password encryption layout items.
 263                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 264                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 265
 266                         // Updated items based on the installation status of OpenKeychain.
 267                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 268                             // Remove the default file path.
 269                             fileNameEditText.setText("");
 270
 271                             // Show the file location card.
 272                             fileLocationCardView.setVisibility(View.VISIBLE);
 273
 274                             if (importRadioButton.isChecked()) {
 275                                 // Show the file name linear layout and the OpenKeychain import instructions.
 276                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 277                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 278
 279                                 // Set the text of the import button to be `Decrypt`.
 280                                 importExportButton.setText(R.string.decrypt);
 281
 282                                 // Disable the import/export button.  The user needs to select a file to import first.
 283                                 importExportButton.setEnabled(false);
 284                             } else if (exportRadioButton.isChecked()) {
 285                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 286                                 fileNameLinearLayout.setVisibility(View.GONE);
 287                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 288
 289                                 // Enable the import/export button.
 290                                 importExportButton.setEnabled(true);
 291                             }
 292                         } else {  // OpenKeychain is not installed.
 293                             // Show the OpenPGP required layout item.
 294                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 295
 296                             // Hide the file location card.
 297                             fileLocationCardView.setVisibility(View.GONE);
 298                         }
 299                         break;
 300                 }
 301             }
 302
 303             @Override
 304             public void onNothingSelected(AdapterView<?> parent) {
 305
 306             }
 307         });
 308
 309         // Update the status of the import/export button when the password changes.
 310         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 311             @Override
 312             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 313                 // Do nothing.
 314             }
 315
 316             @Override
 317             public void onTextChanged(CharSequence s, int start, int before, int count) {
 318                 // Do nothing.
 319             }
 320
 321             @Override
 322             public void afterTextChanged(Editable s) {
 323                 // Enable the import/export button if a file name and password exists.
 324                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 325             }
 326         });
 327
 328         // Update the status of the import/export button when the file name EditText changes.
 329         fileNameEditText.addTextChangedListener(new TextWatcher() {
 330             @Override
 331             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 332                 // Do nothing.
 333             }
 334
 335             @Override
 336             public void onTextChanged(CharSequence s, int start, int before, int count) {
 337                 // Do nothing.
 338             }
 339
 340             @Override
 341             public void afterTextChanged(Editable s) {
 342                 // Adjust the export button according to the encryption spinner position.
 343                 switch (encryptionSpinner.getSelectedItemPosition()) {
 344                     case NO_ENCRYPTION:
 345                         // Enable the import/export button if a file name exists.
 346                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 347                         break;
 348
 349                     case PASSWORD_ENCRYPTION:
 350                         // Enable the import/export button if a file name and password exists.
 351                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 352                         break;
 353
 354                     case OPENPGP_ENCRYPTION:
 355                         // Enable the import/export button if OpenKeychain is installed and a file name exists.
 356                         importExportButton.setEnabled(openKeychainInstalled && !fileNameEditText.getText().toString().isEmpty());
 357                         break;
 358                 }
 359             }
 360         });
 361
 362         // Hide the storage permissions text view on API < 23 as permissions on older devices are automatically granted.
 363         if (Build.VERSION.SDK_INT < 23) {
 364             storagePermissionTextView.setVisibility(View.GONE);
 365         }
 366     }
 367
 368     public void onClickRadioButton(View view) {
 369         // Get handles for the views.
 370         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 371         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 372         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 373         TextView openKeychainImportInstructionTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 374         Button importExportButton = findViewById(R.id.import_export_button);
 375
 376         // Check to see if import or export was selected.
 377         switch (view.getId()) {
 378             case R.id.import_radiobutton:
 379                 // Check to see if OpenPGP encryption is selected.
 380                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 381                     // Show the OpenKeychain import instructions.
 382                     openKeychainImportInstructionTextView.setVisibility(View.VISIBLE);
 383
 384                     // Set the text on the import/export button to be `Decrypt`.
 385                     importExportButton.setText(R.string.decrypt);
 386
 387                     // Enable the decrypt button if there is a file name.
 388                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 389                 } else {  // OpenPGP encryption not selected.
 390                     // Hide the OpenKeychain import instructions.
 391                     openKeychainImportInstructionTextView.setVisibility(View.GONE);
 392
 393                     // Set the text on the import/export button to be `Import`.
 394                     importExportButton.setText(R.string.import_button);
 395                 }
 396
 397                 // Display the file name views.
 398                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 399                 importExportButton.setVisibility(View.VISIBLE);
 400                 break;
 401
 402             case R.id.export_radiobutton:
 403                 // Hide the OpenKeychain import instructions.
 404                 openKeychainImportInstructionTextView.setVisibility(View.GONE);
 405
 406                 // Set the text on the import/export button to be `Export`.
 407                 importExportButton.setText(R.string.export);
 408
 409                 // Show the import/export button.
 410                 importExportButton.setVisibility(View.VISIBLE);
 411
 412                 // Check to see if OpenPGP encryption is selected.
 413                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 414                     // Hide the file name views.
 415                     fileNameLinearLayout.setVisibility(View.GONE);
 416
 417                     // Enable the export button.
 418                     importExportButton.setEnabled(true);
 419                 } else {  // OpenPGP encryption is not selected.
 420                     // Show the file name views.
 421                     fileNameLinearLayout.setVisibility(View.VISIBLE);
 422                 }
 423                 break;
 424         }
 425     }
 426
 427     public void browse(View view) {
 428         // Get a handle for the import radiobutton.
 429         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 430
 431         // Check to see if import or export is selected.
 432         if (importRadioButton.isChecked()) {  // Import is selected.
 433             // Create the file picker intent.
 434             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 435
 436             // Set the intent MIME type to include all files so that everything is visible.
 437             importBrowseIntent.setType("*/*");
 438
 439             // Set the initial directory if the minimum API >= 26.
 440             if (Build.VERSION.SDK_INT >= 26) {
 441                 importBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 442             }
 443
 444             // Request a file that can be opened.
 445             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 446
 447             // Launch the file picker.
 448             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 449         } else {  // Export is selected
 450             // Create the file picker intent.
 451             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 452
 453             // Set the intent MIME type to include all files so that everything is visible.
 454             exportBrowseIntent.setType("*/*");
 455
 456             // Set the initial export file name.
 457             exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_pbs));
 458
 459             // Set the initial directory if the minimum API >= 26.
 460             if (Build.VERSION.SDK_INT >= 26) {
 461                 exportBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 462             }
 463
 464             // Request a file that can be opened.
 465             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 466
 467             // Launch the file picker.
 468             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 469         }
 470     }
 471
 472     public void importExport(View view) {
 473         // Get a handle for the views.
 474         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 475         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 476         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 477
 478         // Check to see if the storage permission is needed.
 479         if ((encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) && exportRadioButton.isChecked()) {  // Permission not needed to export via OpenKeychain.
 480             // Export the settings.
 481             exportSettings();
 482         } else if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 483             // Check to see if import or export is selected.
 484             if (importRadioButton.isChecked()) {  // Import is selected.
 485                 // Import the settings.
 486                 importSettings();
 487             } else {  // Export is selected.
 488                 // Export the settings.
 489                 exportSettings();
 490             }
 491         } else {  // The storage permission has not been granted.
 492             // Get a handle for the file name EditText.
 493             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 494
 495             // Get the file name string.
 496             String fileNameString = fileNameEditText.getText().toString();
 497
 498             // Get the external private directory `File`.
 499             File externalPrivateDirectoryFile = getExternalFilesDir(null);
 500
 501             // Remove the incorrect lint error below that the file might be null.
 502             assert externalPrivateDirectoryFile != null;
 503
 504             // Get the external private directory string.
 505             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 506
 507             // Check to see if the file path is in the external private directory.
 508             if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
 509                 // Check to see if import or export is selected.
 510                 if (importRadioButton.isChecked()) {  // Import is selected.
 511                     // Import the settings.
 512                     importSettings();
 513                 } else {  // Export is selected.
 514                     // Export the settings.
 515                     exportSettings();
 516                 }
 517             } else {  // The file path is in a public directory.
 518                 // Check if the user has previously denied the storage permission.
 519                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
 520                     // Instantiate the storage permission alert dialog.
 521                     DialogFragment storagePermissionDialogFragment = new StoragePermissionDialog();
 522
 523                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
 524                     storagePermissionDialogFragment.show(getSupportFragmentManager(), getString(R.string.storage_permission));
 525                 } else {  // Show the permission request directly.
 526                     // Request the storage permission.  The export will be run when it finishes.
 527                     ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 528                 }
 529             }
 530         }
 531     }
 532
 533     @Override
 534     public void onCloseStoragePermissionDialog() {
 535         // Request the write external storage permission.  The import/export will be run when it finishes.
 536         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 537     }
 538
 539     @Override
 540     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 541         // Get a handle for the import radiobutton.
 542         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 543
 544         // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 545         if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 546             // Run the import or export methods according to which radio button is selected.
 547             if (importRadioButton.isChecked()) {  // Import is selected.
 548                 // Import the settings.
 549                 importSettings();
 550             } else {  // Export is selected.
 551                 // Export the settings.
 552                 exportSettings();
 553             }
 554         } else {  // The storage permission was not granted.
 555             // Display an error snackbar.
 556             Snackbar.make(importRadioButton, getString(R.string.cannot_use_location), Snackbar.LENGTH_LONG).show();
 557         }
 558     }
 559
 560     @Override
 561     public void onActivityResult(int requestCode, int resultCode, Intent data) {
 562         switch (requestCode) {
 563             case (BROWSE_RESULT_CODE):
 564                 // Don't do anything if the user pressed back from the file picker.
 565                 if (resultCode == Activity.RESULT_OK) {
 566                     // Get a handle for the file name edit text.
 567                     EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 568
 569                     // Get the file name URI.
 570                     Uri fileNameUri = data.getData();
 571
 572                     // Remove the lint warning that the file name URI might be null.
 573                     assert fileNameUri != null;
 574
 575                     // Get the raw file name path.
 576                     String rawFileNamePath = fileNameUri.getPath();
 577
 578                     // Remove the incorrect lint warning that the file name path might be null.
 579                     assert rawFileNamePath != null;
 580
 581                     // Check to see if the file name Path includes a valid storage location.
 582                     if (rawFileNamePath.contains(":")) {  // The path is valid.
 583                         // Split the path into the initial content uri and the final path information.
 584                         String fileNameContentPath = rawFileNamePath.substring(0, rawFileNamePath.indexOf(":"));
 585                         String fileNameFinalPath = rawFileNamePath.substring(rawFileNamePath.indexOf(":") + 1);
 586
 587                         // Create the file name path string.
 588                         String fileNamePath;
 589
 590                         // Check to see if the current file name final patch is a complete, valid path
 591                         if (fileNameFinalPath.startsWith("/storage/emulated/")) {  // The existing file name final path is a complete, valid path.
 592                             // Use the provided file name path as is.
 593                             fileNamePath = fileNameFinalPath;
 594                         } else {  // The existing file name final path is not a complete, valid path.
 595                             // Construct the file name path.
 596                             switch (fileNameContentPath) {
 597                                 // The documents home has a special content path.
 598                                 case "/document/home":
 599                                     fileNamePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + fileNameFinalPath;
 600                                     break;
 601
 602                                 // Everything else for the primary user should be in `/document/primary`.
 603                                 case "/document/primary":
 604                                     fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 605                                     break;
 606
 607                                 // Just in case, catch everything else and place it in the external storage directory.
 608                                 default:
 609                                     fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 610                                     break;
 611                             }
 612                         }
 613
 614                         // Set the file name path as the text of the file name edit text.
 615                         fileNameEditText.setText(fileNamePath);
 616                     } else {  // The path is invalid.
 617                         Snackbar.make(fileNameEditText, rawFileNamePath + " " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
 618                     }
 619                 }
 620                 break;
 621
 622             case OPENPGP_EXPORT_RESULT_CODE:
 623                 // Get the temporary unencrypted export file.
 624                 File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 625
 626                 // Delete the temporary unencrypted export file if it exists.
 627                 if (temporaryUnencryptedExportFile.exists()) {
 628                     //noinspection ResultOfMethodCallIgnored
 629                     temporaryUnencryptedExportFile.delete();
 630                 }
 631                 break;
 632         }
 633     }
 634
 635     private void exportSettings() {
 636         // Get a handle for the views.
 637         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 638         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 639
 640         // Instantiate the import export database helper.
 641         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 642
 643         // Get the export file string.
 644         String exportFileString = fileNameEditText.getText().toString();
 645
 646         // Get the export and temporary unencrypted export files.
 647         File exportFile = new File(exportFileString);
 648         File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 649
 650         // Create an export status string.
 651         String exportStatus;
 652
 653         // Export according to the encryption type.
 654         switch (encryptionSpinner.getSelectedItemPosition()) {
 655             case NO_ENCRYPTION:
 656                 // Export the unencrypted file.
 657                 exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
 658
 659                 // Show a disposition snackbar.
 660                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 661                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 662                 } else {
 663                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 664                 }
 665                 break;
 666
 667             case PASSWORD_ENCRYPTION:
 668                 // Create an unencrypted export in a private directory.
 669                 exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 670
 671                 try {
 672                     // Create an unencrypted export file input stream.
 673                     FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 674
 675                     // Delete the encrypted export file if it exists.
 676                     if (exportFile.exists()) {
 677                         //noinspection ResultOfMethodCallIgnored
 678                         exportFile.delete();
 679                     }
 680
 681                     // Create an encrypted export file output stream.
 682                     FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 683
 684                     // Get a handle for the encryption password EditText.
 685                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 686
 687                     // Get the encryption password.
 688                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 689
 690                     // Initialize a secure random number generator.
 691                     SecureRandom secureRandom = new SecureRandom();
 692
 693                     // Get a 256 bit (32 byte) random salt.
 694                     byte[] saltByteArray = new byte[32];
 695                     secureRandom.nextBytes(saltByteArray);
 696
 697                     // Convert the encryption password to a byte array.
 698                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 699
 700                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 701                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 702                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 703                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 704
 705                     // Get a SHA-512 message digest.
 706                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 707
 708                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 709                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 710
 711                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 712                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 713
 714                     // Create an AES secret key from the encryption password byte array.
 715                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 716
 717                     // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 718                     byte[] initializationVector = new byte[12];
 719                     secureRandom.nextBytes(initializationVector);
 720
 721                     // 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.
 722                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 723
 724                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 725                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 726
 727                     // Initialize the cipher.
 728                     cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 729
 730                     // Add the salt and the initialization vector to the export file.
 731                     encryptedExportFileOutputStream.write(saltByteArray);
 732                     encryptedExportFileOutputStream.write(initializationVector);
 733
 734                     // Create a cipher output stream.
 735                     CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
 736
 737                     // 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.
 738                     int numberOfBytesRead;
 739                     byte[] encryptedBytes = new byte[16];
 740
 741                     // 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.
 742                     while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 743                         // Write the data to the cipher output stream.
 744                         cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 745                     }
 746
 747                     // Close the streams.
 748                     cipherOutputStream.flush();
 749                     cipherOutputStream.close();
 750                     encryptedExportFileOutputStream.close();
 751                     unencryptedExportFileInputStream.close();
 752
 753                     // Wipe the encryption data from memory.
 754                     //noinspection UnusedAssignment
 755                     encryptionPasswordString = "";
 756                     Arrays.fill(saltByteArray, (byte) 0);
 757                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 758                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 759                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 760                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 761                     Arrays.fill(initializationVector, (byte) 0);
 762                     Arrays.fill(encryptedBytes, (byte) 0);
 763
 764                     // Delete the temporary unencrypted export file.
 765                     //noinspection ResultOfMethodCallIgnored
 766                     temporaryUnencryptedExportFile.delete();
 767                 } catch (Exception exception) {
 768                     exportStatus = exception.toString();
 769                 }
 770
 771                 // Show a disposition snackbar.
 772                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 773                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 774                 } else {
 775                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 776                 }
 777                 break;
 778
 779             case OPENPGP_ENCRYPTION:
 780                 // Create an unencrypted export in the private location.
 781                 importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 782
 783                 // Create an encryption intent for OpenKeychain.
 784                 Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 785
 786                 // Include the temporary unencrypted export file URI.
 787                 openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryUnencryptedExportFile));
 788
 789                 // Allow OpenKeychain to read the file URI.
 790                 openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 791
 792                 // Send the intent to the OpenKeychain package.
 793                 openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 794
 795                 // Make it so.
 796                 startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 797                 break;
 798         }
 799
 800         // Add the file to the list of recent files.  This doesn't currently work, but maybe it will someday.
 801         MediaScannerConnection.scanFile(this, new String[] {exportFileString}, new String[] {"application/x-sqlite3"}, null);
 802     }
 803
 804     private void importSettings() {
 805         // Get a handle for the views.
 806         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 807         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 808
 809         // Instantiate the import export database helper.
 810         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 811
 812         // Get the import file.
 813         File importFile = new File(fileNameEditText.getText().toString());
 814
 815         // Initialize the import status string
 816         String importStatus = "";
 817
 818         // Import according to the encryption type.
 819         switch (encryptionSpinner.getSelectedItemPosition()) {
 820             case NO_ENCRYPTION:
 821                 // Import the unencrypted file.
 822                 importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
 823                 break;
 824
 825             case PASSWORD_ENCRYPTION:
 826                 // Use a private temporary import location.
 827                 File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 828
 829                 try {
 830                     // Create an encrypted import file input stream.
 831                     FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 832
 833                     // Delete the temporary import file if it exists.
 834                     if (temporaryUnencryptedImportFile.exists()) {
 835                         //noinspection ResultOfMethodCallIgnored
 836                         temporaryUnencryptedImportFile.delete();
 837                     }
 838
 839                     // Create an unencrypted import file output stream.
 840                     FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 841
 842                     // Get a handle for the encryption password EditText.
 843                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 844
 845                     // Get the encryption password.
 846                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 847
 848                     // Get the salt from the beginning of the import file.
 849                     byte[] saltByteArray = new byte[32];
 850                     //noinspection ResultOfMethodCallIgnored
 851                     encryptedImportFileInputStream.read(saltByteArray);
 852
 853                     // Get the initialization vector from the import file.
 854                     byte[] initializationVector = new byte[12];
 855                     //noinspection ResultOfMethodCallIgnored
 856                     encryptedImportFileInputStream.read(initializationVector);
 857
 858                     // Convert the encryption password to a byte array.
 859                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 860
 861                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 862                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 863                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 864                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 865
 866                     // Get a SHA-512 message digest.
 867                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 868
 869                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 870                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 871
 872                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 873                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 874
 875                     // Create an AES secret key from the encryption password byte array.
 876                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 877
 878                     // 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.
 879                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 880
 881                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 882                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 883
 884                     // Initialize the cipher.
 885                     cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 886
 887                     // Create a cipher input stream.
 888                     CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
 889
 890                     // 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.
 891                     int numberOfBytesRead;
 892                     byte[] decryptedBytes = new byte[16];
 893
 894                     // 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.
 895                     while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 896                         // Write the data to the unencrypted import file output stream.
 897                         unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 898                     }
 899
 900                     // Close the streams.
 901                     unencryptedImportFileOutputStream.flush();
 902                     unencryptedImportFileOutputStream.close();
 903                     cipherInputStream.close();
 904                     encryptedImportFileInputStream.close();
 905
 906                     // Wipe the encryption data from memory.
 907                     //noinspection UnusedAssignment
 908                     encryptionPasswordString = "";
 909                     Arrays.fill(saltByteArray, (byte) 0);
 910                     Arrays.fill(initializationVector, (byte) 0);
 911                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 912                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 913                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 914                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 915                     Arrays.fill(decryptedBytes, (byte) 0);
 916
 917                     // Import the unencrypted database from the private location.
 918                     importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
 919
 920                     // Delete the temporary unencrypted import file.
 921                     //noinspection ResultOfMethodCallIgnored
 922                     temporaryUnencryptedImportFile.delete();
 923                 } catch (Exception exception) {
 924                     importStatus = exception.toString();
 925                 }
 926                 break;
 927
 928             case OPENPGP_ENCRYPTION:
 929                 try {
 930                     // Create an decryption intent for OpenKeychain.
 931                     Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 932
 933                     // Include the URI to be decrypted.
 934                     openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), importFile));
 935
 936                     // Allow OpenKeychain to read the file URI.
 937                     openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 938
 939                     // Send the intent to the OpenKeychain package.
 940                     openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 941
 942                     // Make it so.
 943                     startActivity(openKeychainDecryptIntent);
 944                 } catch (IllegalArgumentException exception) {  // The file import location is not valid.
 945                     // Display a snack bar with the import error.
 946                     Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + exception.toString(), Snackbar.LENGTH_INDEFINITE).show();
 947                 }
 948                 break;
 949         }
 950
 951         // Respond to the import disposition.
 952         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
 953             // Create an intent to restart Privacy Browser.
 954             Intent restartIntent = getParentActivityIntent();
 955
 956             // Assert that the intent is not null to remove the lint error below.
 957             assert restartIntent != null;
 958
 959             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 960             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 961
 962             // Create a restart handler.
 963             Handler restartHandler = new Handler();
 964
 965             // Create a restart runnable.
 966             Runnable restartRunnable =  () -> {
 967                 // Restart Privacy Browser.
 968                 startActivity(restartIntent);
 969
 970                 // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
 971                 System.exit(0);
 972             };
 973
 974             // Restart Privacy Browser after 150 milliseconds to allow enough time for the preferences to be saved.
 975             restartHandler.postDelayed(restartRunnable, 150);
 976
 977         } else if (!(encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION)){  // The import was not successful.
 978             // Display a snack bar with the import error.
 979             Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 980         }
 981     }
 982 }