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.pm.PackageManager;
  26 import android.media.MediaScannerConnection;
  27 import android.net.Uri;
  28 import android.os.Build;
  29 import android.os.Bundle;
  30 import android.os.Environment;
  31 import android.provider.DocumentsContract;
  32 import android.text.Editable;
  33 import android.text.TextWatcher;
  34 import android.view.View;
  35 import android.view.WindowManager;
  36 import android.widget.AdapterView;
  37 import android.widget.ArrayAdapter;
  38 import android.widget.Button;
  39 import android.widget.EditText;
  40 import android.widget.LinearLayout;
  41 import android.widget.RadioButton;
  42 import android.widget.Spinner;
  43 import android.widget.TextView;
  44
  45 import androidx.annotation.NonNull;
  46 import androidx.appcompat.app.ActionBar;
  47 import androidx.appcompat.app.AppCompatActivity;
  48 import androidx.appcompat.widget.Toolbar;
  49 import androidx.cardview.widget.CardView;
  50 import androidx.core.app.ActivityCompat;
  51 import androidx.core.content.ContextCompat;
  52 import androidx.core.content.FileProvider;
  53 import androidx.fragment.app.DialogFragment;
  54
  55 import com.google.android.material.snackbar.Snackbar;
  56 import com.google.android.material.textfield.TextInputLayout;
  57
  58 import com.stoutner.privacybrowser.R;
  59 import com.stoutner.privacybrowser.dialogs.StoragePermissionDialog;
  60 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  61
  62 import java.io.File;
  63 import java.io.FileInputStream;
  64 import java.io.FileOutputStream;
  65 import java.nio.charset.StandardCharsets;
  66 import java.security.MessageDigest;
  67 import java.security.SecureRandom;
  68 import java.util.Arrays;
  69
  70 import javax.crypto.Cipher;
  71 import javax.crypto.CipherInputStream;
  72 import javax.crypto.CipherOutputStream;
  73 import javax.crypto.spec.GCMParameterSpec;
  74 import javax.crypto.spec.SecretKeySpec;
  75
  76 public class ImportExportActivity extends AppCompatActivity implements StoragePermissionDialog.StoragePermissionDialogListener {
  77     // Create the encryption constants.
  78     private final int NO_ENCRYPTION = 0;
  79     private final int PASSWORD_ENCRYPTION = 1;
  80     private final int OPENPGP_ENCRYPTION = 2;
  81
  82     // Create the activity result constants.
  83     private final int BROWSE_RESULT_CODE = 0;
  84     private final int OPENPGP_EXPORT_RESULT_CODE = 1;
  85
  86     // `openKeychainInstalled` is accessed from an inner class.
  87     private boolean openKeychainInstalled;
  88
  89     @Override
  90     public void onCreate(Bundle savedInstanceState) {
  91         // Disable screenshots if not allowed.
  92         if (!MainWebViewActivity.allowScreenshots) {
  93             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
  94         }
  95
  96         // Set the activity theme.
  97         if (MainWebViewActivity.darkTheme) {
  98             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
  99         } else {
 100             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
 101         }
 102
 103         // Run the default commands.
 104         super.onCreate(savedInstanceState);
 105
 106         // Set the content view.
 107         setContentView(R.layout.import_export_coordinatorlayout);
 108
 109         // Use the `SupportActionBar` from `android.support.v7.app.ActionBar` until the minimum API is >= 21.
 110         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 111         setSupportActionBar(toolbar);
 112
 113         // Get a handle for the action bar.
 114         ActionBar actionBar = getSupportActionBar();
 115
 116         // Remove the incorrect lint warning that the action bar might be null.
 117         assert actionBar != null;
 118
 119         // Display the home arrow on the support action bar.
 120         actionBar.setDisplayHomeAsUpEnabled(true);
 121
 122         // Find out if we are running KitKat
 123         boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
 124
 125         // Find out if OpenKeychain is installed.
 126         try {
 127             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 128         } catch (PackageManager.NameNotFoundException exception) {
 129             openKeychainInstalled = false;
 130         }
 131
 132         // Get handles for the views that need to be modified.
 133         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 134         TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
 135         EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 136         TextView kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
 137         TextView openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 138         CardView fileLocationCardView = findViewById(R.id.file_location_cardview);
 139         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 140         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 141         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 142         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 143         TextView openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 144         Button importExportButton = findViewById(R.id.import_export_button);
 145         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 146
 147         // Create an array adapter for the spinner.
 148         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 149
 150         // Set the drop down view resource on the spinner.
 151         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 152
 153         // Set the array adapter for the spinner.
 154         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 155
 156         // Initially hide the unneeded views.
 157         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 158         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 159         openKeychainRequiredTextView.setVisibility(View.GONE);
 160         fileNameLinearLayout.setVisibility(View.GONE);
 161         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 162         importExportButton.setVisibility(View.GONE);
 163
 164         // Create strings for the default file paths.
 165         String defaultFilePath;
 166         String defaultPasswordEncryptionFilePath;
 167
 168         // Set the default file paths according to the storage permission status.
 169         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 170             // Set the default file paths to use the external public directory.
 171             defaultFilePath = Environment.getExternalStorageDirectory() + "/" + getString(R.string.settings_pbs);
 172             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 173         } else {  // The storage permission has not been granted.
 174             // Set the default file paths to use the external private directory.
 175             defaultFilePath = getApplicationContext().getExternalFilesDir(null) + "/" + getString(R.string.settings_pbs);
 176             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 177         }
 178
 179         // Set the default file path.
 180         fileNameEditText.setText(defaultFilePath);
 181
 182         // Display the encryption information when the spinner changes.
 183         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 184             @Override
 185             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 186                 switch (position) {
 187                     case NO_ENCRYPTION:
 188                         // Hide the unneeded layout items.
 189                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 190                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 191                         openKeychainRequiredTextView.setVisibility(View.GONE);
 192                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 193
 194                         // Show the file location card.
 195                         fileLocationCardView.setVisibility(View.VISIBLE);
 196
 197                         // Show the file name linear layout if either import or export is checked.
 198                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 199                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 200                         }
 201
 202                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 203                         if (importRadioButton.isChecked()) {
 204                             importExportButton.setText(R.string.import_button);
 205                         }
 206
 207                         // Reset the default file path.
 208                         fileNameEditText.setText(defaultFilePath);
 209
 210                         // Enable the import/export button if a file name exists.
 211                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 212                         break;
 213
 214                     case PASSWORD_ENCRYPTION:
 215                         if (runningKitKat) {
 216                             // Show the KitKat password encryption message.
 217                             kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
 218
 219                             // Hide the OpenPGP required text view and the file location card.
 220                             openKeychainRequiredTextView.setVisibility(View.GONE);
 221                             fileLocationCardView.setVisibility(View.GONE);
 222                         } else {
 223                             // Hide the OpenPGP layout items.
 224                             openKeychainRequiredTextView.setVisibility(View.GONE);
 225                             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 226
 227                             // Show the password encryption layout items.
 228                             passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
 229
 230                             // Show the file location card.
 231                             fileLocationCardView.setVisibility(View.VISIBLE);
 232
 233                             // Show the file name linear layout if either import or export is checked.
 234                             if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 235                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 236                             }
 237
 238                             // Reset the text of the import button, which may have been changed to `Decrypt`.
 239                             if (importRadioButton.isChecked()) {
 240                                 importExportButton.setText(R.string.import_button);
 241                             }
 242
 243                             // Update the default file path.
 244                             fileNameEditText.setText(defaultPasswordEncryptionFilePath);
 245
 246                             // Enable the import/export button if a password exists.
 247                             importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 248                         }
 249                         break;
 250
 251                     case OPENPGP_ENCRYPTION:
 252                         // Hide the password encryption layout items.
 253                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 254                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 255
 256                         // Updated items based on the installation status of OpenKeychain.
 257                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 258                             // Remove the default file path.
 259                             fileNameEditText.setText("");
 260
 261                             // Show the file location card.
 262                             fileLocationCardView.setVisibility(View.VISIBLE);
 263
 264                             if (importRadioButton.isChecked()) {
 265                                 // Show the file name linear layout and the OpenKeychain import instructions.
 266                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 267                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 268
 269                                 // Set the text of the import button to be `Decrypt`.
 270                                 importExportButton.setText(R.string.decrypt);
 271
 272                                 // Disable the import/export button.  The user needs to select a file to import first.
 273                                 importExportButton.setEnabled(false);
 274                             } else if (exportRadioButton.isChecked()) {
 275                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 276                                 fileNameLinearLayout.setVisibility(View.GONE);
 277                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 278
 279                                 // Enable the import/export button.
 280                                 importExportButton.setEnabled(true);
 281                             }
 282                         } else {  // OpenKeychain is not installed.
 283                             // Show the OpenPGP required layout item.
 284                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 285
 286                             // Hide the file location card.
 287                             fileLocationCardView.setVisibility(View.GONE);
 288                         }
 289                         break;
 290                 }
 291             }
 292
 293             @Override
 294             public void onNothingSelected(AdapterView<?> parent) {
 295
 296             }
 297         });
 298
 299         // Update the status of the import/export button when the password changes.
 300         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 301             @Override
 302             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 303                 // Do nothing.
 304             }
 305
 306             @Override
 307             public void onTextChanged(CharSequence s, int start, int before, int count) {
 308                 // Do nothing.
 309             }
 310
 311             @Override
 312             public void afterTextChanged(Editable s) {
 313                 // Enable the import/export button if a file name and password exists.
 314                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 315             }
 316         });
 317
 318         // Update the status of the import/export button when the file name EditText changes.
 319         fileNameEditText.addTextChangedListener(new TextWatcher() {
 320             @Override
 321             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 322                 // Do nothing.
 323             }
 324
 325             @Override
 326             public void onTextChanged(CharSequence s, int start, int before, int count) {
 327                 // Do nothing.
 328             }
 329
 330             @Override
 331             public void afterTextChanged(Editable s) {
 332                 // Adjust the export button according to the encryption spinner position.
 333                 switch (encryptionSpinner.getSelectedItemPosition()) {
 334                     case NO_ENCRYPTION:
 335                         // Enable the import/export button if a file name exists.
 336                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 337                         break;
 338
 339                     case PASSWORD_ENCRYPTION:
 340                         // Enable the import/export button if a file name and password exists.
 341                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 342                         break;
 343
 344                     case OPENPGP_ENCRYPTION:
 345                         // Enable the import/export button if OpenKeychain is installed and a file name exists.
 346                         importExportButton.setEnabled(openKeychainInstalled && !fileNameEditText.getText().toString().isEmpty());
 347                         break;
 348                 }
 349             }
 350         });
 351
 352         // Hide the storage permissions text view on API < 23 as permissions on older devices are automatically granted.
 353         if (Build.VERSION.SDK_INT < 23) {
 354             storagePermissionTextView.setVisibility(View.GONE);
 355         }
 356     }
 357
 358     public void onClickRadioButton(View view) {
 359         // Get handles for the views.
 360         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 361         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 362         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 363         TextView openKeychainImportInstructionTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 364         Button importExportButton = findViewById(R.id.import_export_button);
 365
 366         // Check to see if import or export was selected.
 367         switch (view.getId()) {
 368             case R.id.import_radiobutton:
 369                 // Check to see if OpenPGP encryption is selected.
 370                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 371                     // Show the OpenKeychain import instructions.
 372                     openKeychainImportInstructionTextView.setVisibility(View.VISIBLE);
 373
 374                     // Set the text on the import/export button to be `Decrypt`.
 375                     importExportButton.setText(R.string.decrypt);
 376
 377                     // Enable the decrypt button if there is a file name.
 378                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 379                 } else {  // OpenPGP encryption not selected.
 380                     // Hide the OpenKeychain import instructions.
 381                     openKeychainImportInstructionTextView.setVisibility(View.GONE);
 382
 383                     // Set the text on the import/export button to be `Import`.
 384                     importExportButton.setText(R.string.import_button);
 385                 }
 386
 387                 // Display the file name views.
 388                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 389                 importExportButton.setVisibility(View.VISIBLE);
 390                 break;
 391
 392             case R.id.export_radiobutton:
 393                 // Hide the OpenKeychain import instructions.
 394                 openKeychainImportInstructionTextView.setVisibility(View.GONE);
 395
 396                 // Set the text on the import/export button to be `Export`.
 397                 importExportButton.setText(R.string.export);
 398
 399                 // Show the import/export button.
 400                 importExportButton.setVisibility(View.VISIBLE);
 401
 402                 // Check to see if OpenPGP encryption is selected.
 403                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 404                     // Hide the file name views.
 405                     fileNameLinearLayout.setVisibility(View.GONE);
 406
 407                     // Enable the export button.
 408                     importExportButton.setEnabled(true);
 409                 } else {  // OpenPGP encryption is not selected.
 410                     // Show the file name views.
 411                     fileNameLinearLayout.setVisibility(View.VISIBLE);
 412                 }
 413                 break;
 414         }
 415     }
 416
 417     public void browse(View view) {
 418         // Get a handle for the import radiobutton.
 419         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 420
 421         // Check to see if import or export is selected.
 422         if (importRadioButton.isChecked()) {  // Import is selected.
 423             // Create the file picker intent.
 424             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 425
 426             // Set the intent MIME type to include all files so that everything is visible.
 427             importBrowseIntent.setType("*/*");
 428
 429             // Set the initial directory if the minimum API >= 26.
 430             if (Build.VERSION.SDK_INT >= 26) {
 431                 importBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 432             }
 433
 434             // Request a file that can be opened.
 435             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 436
 437             // Launch the file picker.
 438             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 439         } else {  // Export is selected
 440             // Create the file picker intent.
 441             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 442
 443             // Set the intent MIME type to include all files so that everything is visible.
 444             exportBrowseIntent.setType("*/*");
 445
 446             // Set the initial export file name.
 447             exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings_pbs));
 448
 449             // Set the initial directory if the minimum API >= 26.
 450             if (Build.VERSION.SDK_INT >= 26) {
 451                 exportBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 452             }
 453
 454             // Request a file that can be opened.
 455             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 456
 457             // Launch the file picker.
 458             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 459         }
 460     }
 461
 462     public void importExport(View view) {
 463         // Get a handle for the views.
 464         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 465         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 466         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 467
 468         // Check to see if the storage permission is needed.
 469         if ((encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) && exportRadioButton.isChecked()) {  // Permission not needed to export via OpenKeychain.
 470             // Export the settings.
 471             exportSettings();
 472         } else if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 473             // Check to see if import or export is selected.
 474             if (importRadioButton.isChecked()) {  // Import is selected.
 475                 // Import the settings.
 476                 importSettings();
 477             } else {  // Export is selected.
 478                 // Export the settings.
 479                 exportSettings();
 480             }
 481         } else {  // The storage permission has not been granted.
 482             // Get a handle for the file name EditText.
 483             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 484
 485             // Get the file name string.
 486             String fileNameString = fileNameEditText.getText().toString();
 487
 488             // Get the external private directory `File`.
 489             File externalPrivateDirectoryFile = getExternalFilesDir(null);
 490
 491             // Remove the incorrect lint error below that the file might be null.
 492             assert externalPrivateDirectoryFile != null;
 493
 494             // Get the external private directory string.
 495             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 496
 497             // Check to see if the file path is in the external private directory.
 498             if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
 499                 // Check to see if import or export is selected.
 500                 if (importRadioButton.isChecked()) {  // Import is selected.
 501                     // Import the settings.
 502                     importSettings();
 503                 } else {  // Export is selected.
 504                     // Export the settings.
 505                     exportSettings();
 506                 }
 507             } else {  // The file path is in a public directory.
 508                 // Check if the user has previously denied the storage permission.
 509                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
 510                     // Instantiate the storage permission alert dialog.
 511                     DialogFragment storagePermissionDialogFragment = new StoragePermissionDialog();
 512
 513                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
 514                     storagePermissionDialogFragment.show(getSupportFragmentManager(), getString(R.string.storage_permission));
 515                 } else {  // Show the permission request directly.
 516                     // Request the storage permission.  The export will be run when it finishes.
 517                     ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 518                 }
 519             }
 520         }
 521     }
 522
 523     @Override
 524     public void onCloseStoragePermissionDialog() {
 525         // Request the write external storage permission.  The import/export will be run when it finishes.
 526         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 527     }
 528
 529     @Override
 530     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 531         // Get a handle for the import radiobutton.
 532         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 533
 534         // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 535         if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 536             // Run the import or export methods according to which radio button is selected.
 537             if (importRadioButton.isChecked()) {  // Import is selected.
 538                 // Import the settings.
 539                 importSettings();
 540             } else {  // Export is selected.
 541                 // Export the settings.
 542                 exportSettings();
 543             }
 544         } else {  // The storage permission was not granted.
 545             // Display an error snackbar.
 546             Snackbar.make(importRadioButton, getString(R.string.cannot_use_location), Snackbar.LENGTH_LONG).show();
 547         }
 548     }
 549
 550     @Override
 551     public void onActivityResult(int requestCode, int resultCode, Intent data) {
 552         switch (requestCode) {
 553             case (BROWSE_RESULT_CODE):
 554                 // Don't do anything if the user pressed back from the file picker.
 555                 if (resultCode == Activity.RESULT_OK) {
 556                     // Get a handle for the file name edit text.
 557                     EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 558
 559                     // Get the file name URI.
 560                     Uri fileNameUri = data.getData();
 561
 562                     // Remove the lint warning that the file name URI might be null.
 563                     assert fileNameUri != null;
 564
 565                     // Get the raw file name path.
 566                     String rawFileNamePath = fileNameUri.getPath();
 567
 568                     // Remove the incorrect lint warning that the file name path might be null.
 569                     assert rawFileNamePath != null;
 570
 571                     // Check to see if the file name Path includes a valid storage location.
 572                     if (rawFileNamePath.contains(":")) {  // The path is valid.
 573                         // Split the path into the initial content uri and the final path information.
 574                         String fileNameContentPath = rawFileNamePath.substring(0, rawFileNamePath.indexOf(":"));
 575                         String fileNameFinalPath = rawFileNamePath.substring(rawFileNamePath.indexOf(":") + 1);
 576
 577                         // Create the file name path string.
 578                         String fileNamePath;
 579
 580                         // Construct the file name path.
 581                         switch (fileNameContentPath) {
 582                             // The documents home has a special content path.
 583                             case "/document/home":
 584                                 fileNamePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + fileNameFinalPath;
 585                                 break;
 586
 587                             // Everything else for the primary user should be in `/document/primary`.
 588                             case "/document/primary":
 589                                 fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 590                                 break;
 591
 592                             // Just in case, catch everything else and place it in the external storage directory.
 593                             default:
 594                                 fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 595                                 break;
 596                         }
 597
 598                         // Set the file name path as the text of the file name EditText.
 599                         fileNameEditText.setText(fileNamePath);
 600                     } else {  // The path is invalid.
 601                         Snackbar.make(fileNameEditText, rawFileNamePath + " " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
 602                     }
 603                 }
 604                 break;
 605
 606             case OPENPGP_EXPORT_RESULT_CODE:
 607                 // Get the temporary unencrypted export file.
 608                 File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 609
 610                 // Delete the temporary unencrypted export file if it exists.
 611                 if (temporaryUnencryptedExportFile.exists()) {
 612                     //noinspection ResultOfMethodCallIgnored
 613                     temporaryUnencryptedExportFile.delete();
 614                 }
 615                 break;
 616         }
 617     }
 618
 619     private void exportSettings() {
 620         // Get a handle for the views.
 621         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 622         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 623
 624         // Instantiate the import export database helper.
 625         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 626
 627         // Get the export file string.
 628         String exportFileString = fileNameEditText.getText().toString();
 629
 630         // Get the export and temporary unencrypted export files.
 631         File exportFile = new File(exportFileString);
 632         File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 633
 634         // Create an export status string.
 635         String exportStatus;
 636
 637         // Export according to the encryption type.
 638         switch (encryptionSpinner.getSelectedItemPosition()) {
 639             case NO_ENCRYPTION:
 640                 // Export the unencrypted file.
 641                 exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
 642
 643                 // Show a disposition snackbar.
 644                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 645                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 646                 } else {
 647                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 648                 }
 649                 break;
 650
 651             case PASSWORD_ENCRYPTION:
 652                 // Create an unencrypted export in a private directory.
 653                 exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 654
 655                 try {
 656                     // Create an unencrypted export file input stream.
 657                     FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 658
 659                     // Delete the encrypted export file if it exists.
 660                     if (exportFile.exists()) {
 661                         //noinspection ResultOfMethodCallIgnored
 662                         exportFile.delete();
 663                     }
 664
 665                     // Create an encrypted export file output stream.
 666                     FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 667
 668                     // Get a handle for the encryption password EditText.
 669                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 670
 671                     // Get the encryption password.
 672                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 673
 674                     // Initialize a secure random number generator.
 675                     SecureRandom secureRandom = new SecureRandom();
 676
 677                     // Get a 256 bit (32 byte) random salt.
 678                     byte[] saltByteArray = new byte[32];
 679                     secureRandom.nextBytes(saltByteArray);
 680
 681                     // Convert the encryption password to a byte array.
 682                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 683
 684                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 685                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 686                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 687                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 688
 689                     // Get a SHA-512 message digest.
 690                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 691
 692                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 693                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 694
 695                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 696                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 697
 698                     // Create an AES secret key from the encryption password byte array.
 699                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 700
 701                     // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 702                     byte[] initializationVector = new byte[12];
 703                     secureRandom.nextBytes(initializationVector);
 704
 705                     // 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.
 706                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 707
 708                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 709                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 710
 711                     // Initialize the cipher.
 712                     cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 713
 714                     // Add the salt and the initialization vector to the export file.
 715                     encryptedExportFileOutputStream.write(saltByteArray);
 716                     encryptedExportFileOutputStream.write(initializationVector);
 717
 718                     // Create a cipher output stream.
 719                     CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
 720
 721                     // 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.
 722                     int numberOfBytesRead;
 723                     byte[] encryptedBytes = new byte[16];
 724
 725                     // 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.
 726                     while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 727                         // Write the data to the cipher output stream.
 728                         cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 729                     }
 730
 731                     // Close the streams.
 732                     cipherOutputStream.flush();
 733                     cipherOutputStream.close();
 734                     encryptedExportFileOutputStream.close();
 735                     unencryptedExportFileInputStream.close();
 736
 737                     // Wipe the encryption data from memory.
 738                     //noinspection UnusedAssignment
 739                     encryptionPasswordString = "";
 740                     Arrays.fill(saltByteArray, (byte) 0);
 741                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 742                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 743                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 744                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 745                     Arrays.fill(initializationVector, (byte) 0);
 746                     Arrays.fill(encryptedBytes, (byte) 0);
 747
 748                     // Delete the temporary unencrypted export file.
 749                     //noinspection ResultOfMethodCallIgnored
 750                     temporaryUnencryptedExportFile.delete();
 751                 } catch (Exception exception) {
 752                     exportStatus = exception.toString();
 753                 }
 754
 755                 // Show a disposition snackbar.
 756                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 757                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 758                 } else {
 759                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 760                 }
 761                 break;
 762
 763             case OPENPGP_ENCRYPTION:
 764                 // Create an unencrypted export in the private location.
 765                 importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 766
 767                 // Create an encryption intent for OpenKeychain.
 768                 Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 769
 770                 // Include the temporary unencrypted export file URI.
 771                 openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryUnencryptedExportFile));
 772
 773                 // Allow OpenKeychain to read the file URI.
 774                 openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 775
 776                 // Send the intent to the OpenKeychain package.
 777                 openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 778
 779                 // Make it so.
 780                 startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 781                 break;
 782         }
 783
 784         // Add the file to the list of recent files.  This doesn't currently work, but maybe it will someday.
 785         MediaScannerConnection.scanFile(this, new String[] {exportFileString}, new String[] {"application/x-sqlite3"}, null);
 786     }
 787
 788     private void importSettings() {
 789         // Get a handle for the views.
 790         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 791         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 792
 793         // Instantiate the import export database helper.
 794         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 795
 796         // Get the import file.
 797         File importFile = new File(fileNameEditText.getText().toString());
 798
 799         // Initialize the import status string
 800         String importStatus = "";
 801
 802         // Import according to the encryption type.
 803         switch (encryptionSpinner.getSelectedItemPosition()) {
 804             case NO_ENCRYPTION:
 805                 // Import the unencrypted file.
 806                 importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
 807                 break;
 808
 809             case PASSWORD_ENCRYPTION:
 810                 // Use a private temporary import location.
 811                 File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings_pbs));
 812
 813                 try {
 814                     // Create an encrypted import file input stream.
 815                     FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 816
 817                     // Delete the temporary import file if it exists.
 818                     if (temporaryUnencryptedImportFile.exists()) {
 819                         //noinspection ResultOfMethodCallIgnored
 820                         temporaryUnencryptedImportFile.delete();
 821                     }
 822
 823                     // Create an unencrypted import file output stream.
 824                     FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 825
 826                     // Get a handle for the encryption password EditText.
 827                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 828
 829                     // Get the encryption password.
 830                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 831
 832                     // Get the salt from the beginning of the import file.
 833                     byte[] saltByteArray = new byte[32];
 834                     //noinspection ResultOfMethodCallIgnored
 835                     encryptedImportFileInputStream.read(saltByteArray);
 836
 837                     // Get the initialization vector from the import file.
 838                     byte[] initializationVector = new byte[12];
 839                     //noinspection ResultOfMethodCallIgnored
 840                     encryptedImportFileInputStream.read(initializationVector);
 841
 842                     // Convert the encryption password to a byte array.
 843                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 844
 845                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 846                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 847                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 848                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 849
 850                     // Get a SHA-512 message digest.
 851                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 852
 853                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 854                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 855
 856                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 857                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 858
 859                     // Create an AES secret key from the encryption password byte array.
 860                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 861
 862                     // 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.
 863                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 864
 865                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 866                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 867
 868                     // Initialize the cipher.
 869                     cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 870
 871                     // Create a cipher input stream.
 872                     CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
 873
 874                     // 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.
 875                     int numberOfBytesRead;
 876                     byte[] decryptedBytes = new byte[16];
 877
 878                     // 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.
 879                     while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 880                         // Write the data to the unencrypted import file output stream.
 881                         unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 882                     }
 883
 884                     // Close the streams.
 885                     unencryptedImportFileOutputStream.flush();
 886                     unencryptedImportFileOutputStream.close();
 887                     cipherInputStream.close();
 888                     encryptedImportFileInputStream.close();
 889
 890                     // Wipe the encryption data from memory.
 891                     //noinspection UnusedAssignment
 892                     encryptionPasswordString = "";
 893                     Arrays.fill(saltByteArray, (byte) 0);
 894                     Arrays.fill(initializationVector, (byte) 0);
 895                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 896                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 897                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 898                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 899                     Arrays.fill(decryptedBytes, (byte) 0);
 900
 901                     // Import the unencrypted database from the private location.
 902                     importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
 903
 904                     // Delete the temporary unencrypted import file.
 905                     //noinspection ResultOfMethodCallIgnored
 906                     temporaryUnencryptedImportFile.delete();
 907                 } catch (Exception exception) {
 908                     importStatus = exception.toString();
 909                 }
 910                 break;
 911
 912             case OPENPGP_ENCRYPTION:
 913                 try {
 914                     // Create an decryption intent for OpenKeychain.
 915                     Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 916
 917                     // Include the URI to be decrypted.
 918                     openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), importFile));
 919
 920                     // Allow OpenKeychain to read the file URI.
 921                     openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 922
 923                     // Send the intent to the OpenKeychain package.
 924                     openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 925
 926                     // Make it so.
 927                     startActivity(openKeychainDecryptIntent);
 928                 } catch (IllegalArgumentException exception) {  // The file import location is not valid.
 929                     // Display a snack bar with the import error.
 930                     Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + exception.toString(), Snackbar.LENGTH_INDEFINITE).show();
 931                 }
 932                 break;
 933         }
 934
 935         // Respond to the import disposition.
 936         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
 937             // Create an intent to restart Privacy Browser.
 938             Intent restartIntent = getParentActivityIntent();
 939
 940             // Assert that the intent is not null to remove the lint error below.
 941             assert restartIntent != null;
 942
 943             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 944             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 945
 946             // Make it so.
 947             startActivity(restartIntent);
 948         } else if (!(encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION)){  // The import was not successful.
 949             // Display a snack bar with the import error.
 950             Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 951         }
 952     }
 953 }