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

   1 /*
   2  * Copyright © 2018-2022 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser Android <https://www.stoutner.com/privacy-browser-android>.
   5  *
   6  * Privacy Browser Android 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 Android 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 Android.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 package com.stoutner.privacybrowser.activities;
  21
  22 import android.app.Activity;
  23 import android.content.Intent;
  24 import android.content.SharedPreferences;
  25 import android.content.pm.PackageManager;
  26 import android.net.Uri;
  27 import android.os.Bundle;
  28 import android.os.Handler;
  29 import android.preference.PreferenceManager;
  30 import android.text.Editable;
  31 import android.text.TextWatcher;
  32 import android.view.View;
  33 import android.view.WindowManager;
  34 import android.widget.AdapterView;
  35 import android.widget.ArrayAdapter;
  36 import android.widget.Button;
  37 import android.widget.EditText;
  38 import android.widget.LinearLayout;
  39 import android.widget.RadioButton;
  40 import android.widget.Spinner;
  41 import android.widget.TextView;
  42
  43 import androidx.annotation.NonNull;
  44 import androidx.appcompat.app.ActionBar;
  45 import androidx.appcompat.app.AppCompatActivity;
  46 import androidx.appcompat.widget.Toolbar;
  47 import androidx.cardview.widget.CardView;
  48 import androidx.core.content.FileProvider;
  49
  50 import com.google.android.material.snackbar.Snackbar;
  51 import com.google.android.material.textfield.TextInputLayout;
  52
  53 import com.stoutner.privacybrowser.BuildConfig;
  54 import com.stoutner.privacybrowser.R;
  55 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  56
  57 import java.io.File;
  58 import java.io.FileInputStream;
  59 import java.io.FileNotFoundException;
  60 import java.io.FileOutputStream;
  61 import java.io.InputStream;
  62 import java.io.OutputStream;
  63 import java.nio.charset.StandardCharsets;
  64 import java.security.MessageDigest;
  65 import java.security.SecureRandom;
  66 import java.util.Arrays;
  67
  68 import javax.crypto.Cipher;
  69 import javax.crypto.CipherInputStream;
  70 import javax.crypto.CipherOutputStream;
  71 import javax.crypto.spec.GCMParameterSpec;
  72 import javax.crypto.spec.SecretKeySpec;
  73
  74 public class ImportExportActivity extends AppCompatActivity {
  75     // Define the encryption constants.
  76     private final int NO_ENCRYPTION = 0;
  77     private final int PASSWORD_ENCRYPTION = 1;
  78     private final int OPENPGP_ENCRYPTION = 2;
  79
  80     // Define the activity result constants.
  81     private final int BROWSE_RESULT_CODE = 0;
  82     private final int OPENPGP_IMPORT_RESULT_CODE = 1;
  83     private final int OPENPGP_EXPORT_RESULT_CODE = 2;
  84
  85     // Define the saved instance state constants.
  86     private final String ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY = "encryption_password_textinputlayout_visibility";
  87     private final String KITKAT_PASSWORD_ENCRYPTED_TEXTVIEW_VISIBILITY = "kitkat_password_encrypted_textview_visibility";
  88     private final String OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY = "open_keychain_required_textview_visibility";
  89     private final String FILE_LOCATION_CARD_VIEW = "file_location_card_view";
  90     private final String FILE_NAME_LINEARLAYOUT_VISIBILITY = "file_name_linearlayout_visibility";
  91     private final String OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY = "open_keychain_import_instructions_textview_visibility";
  92     private final String IMPORT_EXPORT_BUTTON_VISIBILITY = "import_export_button_visibility";
  93     private final String FILE_NAME_TEXT = "file_name_text";
  94     private final String IMPORT_EXPORT_BUTTON_TEXT = "import_export_button_text";
  95
  96     // Define the class views.
  97     Spinner encryptionSpinner;
  98     TextInputLayout encryptionPasswordTextInputLayout;
  99     EditText encryptionPasswordEditText;
 100     TextView kitKatPasswordEncryptionTextView;
 101     TextView openKeychainRequiredTextView;
 102     CardView fileLocationCardView;
 103     RadioButton importRadioButton;
 104     LinearLayout fileNameLinearLayout;
 105     EditText fileNameEditText;
 106     TextView openKeychainImportInstructionsTextView;
 107     Button importExportButton;
 108
 109     // Define the class variables.
 110     private boolean openKeychainInstalled;
 111     private File temporaryPgpEncryptedImportFile;
 112     private File temporaryPreEncryptedExportFile;
 113
 114     @Override
 115     public void onCreate(Bundle savedInstanceState) {
 116         // Get a handle for the shared preferences.
 117         SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
 118
 119         // Get the preferences.
 120         boolean allowScreenshots = sharedPreferences.getBoolean(getString(R.string.allow_screenshots_key), false);
 121         boolean bottomAppBar = sharedPreferences.getBoolean(getString(R.string.bottom_app_bar_key), false);
 122
 123         // Disable screenshots if not allowed.
 124         if (!allowScreenshots) {
 125             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
 126         }
 127
 128         // Set the theme.
 129         setTheme(R.style.PrivacyBrowser);
 130
 131         // Run the default commands.
 132         super.onCreate(savedInstanceState);
 133
 134         // Set the content view.
 135         if (bottomAppBar) {
 136             setContentView(R.layout.import_export_bottom_appbar);
 137         } else {
 138             setContentView(R.layout.import_export_top_appbar);
 139         }
 140
 141         // Get a handle for the toolbar.
 142         Toolbar toolbar = findViewById(R.id.import_export_toolbar);
 143
 144         // Set the support action bar.
 145         setSupportActionBar(toolbar);
 146
 147         // Get a handle for the action bar.
 148         ActionBar actionBar = getSupportActionBar();
 149
 150         // Remove the incorrect lint warning that the action bar might be null.
 151         assert actionBar != null;
 152
 153         // Display the home arrow on the support action bar.
 154         actionBar.setDisplayHomeAsUpEnabled(true);
 155
 156         // Find out if OpenKeychain is installed.
 157         try {
 158             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 159         } catch (PackageManager.NameNotFoundException exception) {
 160             openKeychainInstalled = false;
 161         }
 162
 163         // Get handles for the views that need to be modified.
 164         encryptionSpinner = findViewById(R.id.encryption_spinner);
 165         encryptionPasswordTextInputLayout = findViewById(R.id.encryption_password_textinputlayout);
 166         encryptionPasswordEditText = findViewById(R.id.encryption_password_edittext);
 167         openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 168         fileLocationCardView = findViewById(R.id.file_location_cardview);
 169         importRadioButton = findViewById(R.id.import_radiobutton);
 170         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 171         fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 172         fileNameEditText = findViewById(R.id.file_name_edittext);
 173         openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 174         importExportButton = findViewById(R.id.import_export_button);
 175
 176         // Create an array adapter for the spinner.
 177         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 178
 179         // Set the drop down view resource on the spinner.
 180         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 181
 182         // Set the array adapter for the spinner.
 183         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 184
 185         // Update the UI when the spinner changes.
 186         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 187             @Override
 188             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 189                 switch (position) {
 190                     case NO_ENCRYPTION:
 191                         // Hide the unneeded layout items.
 192                         encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 193                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 194                         openKeychainRequiredTextView.setVisibility(View.GONE);
 195                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 196
 197                         // Show the file location card.
 198                         fileLocationCardView.setVisibility(View.VISIBLE);
 199
 200                         // Show the file name linear layout if either import or export is checked.
 201                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 202                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 203                         }
 204
 205                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 206                         if (importRadioButton.isChecked()) {
 207                             importExportButton.setText(R.string.import_button);
 208                         }
 209
 210                         // Enable the import/export button if the file name is populated.
 211                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 212                         break;
 213
 214                     case PASSWORD_ENCRYPTION:
 215                         // Hide the OpenPGP layout items.
 216                         openKeychainRequiredTextView.setVisibility(View.GONE);
 217                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 218
 219                         // Show the password encryption layout items.
 220                         encryptionPasswordTextInputLayout.setVisibility(View.VISIBLE);
 221
 222                         // Show the file location card.
 223                         fileLocationCardView.setVisibility(View.VISIBLE);
 224
 225                         // Show the file name linear layout if either import or export is checked.
 226                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 227                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 228                         }
 229
 230                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 231                         if (importRadioButton.isChecked()) {
 232                             importExportButton.setText(R.string.import_button);
 233                         }
 234
 235                         // Enable the import/button if both the password and the file name are populated.
 236                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 237                         break;
 238
 239                     case OPENPGP_ENCRYPTION:
 240                         // Hide the password encryption layout items.
 241                         encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 242                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 243
 244                         // Updated items based on the installation status of OpenKeychain.
 245                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 246                             // Show the file location card.
 247                             fileLocationCardView.setVisibility(View.VISIBLE);
 248
 249                             if (importRadioButton.isChecked()) {
 250                                 // Show the file name linear layout and the OpenKeychain import instructions.
 251                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 252                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 253
 254                                 // Set the text of the import button to be `Decrypt`.
 255                                 importExportButton.setText(R.string.decrypt);
 256
 257                                 // Enable the import button if the file name is populated.
 258                                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 259                             } else if (exportRadioButton.isChecked()) {
 260                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 261                                 fileNameLinearLayout.setVisibility(View.GONE);
 262                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 263
 264                                 // Enable the export button.
 265                                 importExportButton.setEnabled(true);
 266                             }
 267                         } else {  // OpenKeychain is not installed.
 268                             // Show the OpenPGP required layout item.
 269                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 270
 271                             // Hide the file location card.
 272                             fileLocationCardView.setVisibility(View.GONE);
 273                         }
 274                         break;
 275                 }
 276             }
 277
 278             @Override
 279             public void onNothingSelected(AdapterView<?> parent) {
 280
 281             }
 282         });
 283
 284         // Update the status of the import/export button when the password changes.
 285         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 286             @Override
 287             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 288                 // Do nothing.
 289             }
 290
 291             @Override
 292             public void onTextChanged(CharSequence s, int start, int before, int count) {
 293                 // Do nothing.
 294             }
 295
 296             @Override
 297             public void afterTextChanged(Editable s) {
 298                 // Enable the import/export button if both the file string and the password are populated.
 299                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 300             }
 301         });
 302
 303         // Update the UI when the file name EditText changes.
 304         fileNameEditText.addTextChangedListener(new TextWatcher() {
 305             @Override
 306             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 307                 // Do nothing.
 308             }
 309
 310             @Override
 311             public void onTextChanged(CharSequence s, int start, int before, int count) {
 312                 // Do nothing.
 313             }
 314
 315             @Override
 316             public void afterTextChanged(Editable s) {
 317                 // Adjust the UI according to the encryption spinner position.
 318                 if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {
 319                     // Enable the import/export button if both the file name and the password are populated.
 320                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 321                 } else {
 322                     // Enable the export button if the file name is populated.
 323                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 324                 }
 325             }
 326         });
 327
 328         // Check to see if the activity has been restarted.
 329         if (savedInstanceState == null) {  // The app has not been restarted.
 330             // Initially hide the unneeded views.
 331             encryptionPasswordTextInputLayout.setVisibility(View.GONE);
 332             kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 333             openKeychainRequiredTextView.setVisibility(View.GONE);
 334             fileNameLinearLayout.setVisibility(View.GONE);
 335             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 336             importExportButton.setVisibility(View.GONE);
 337         } else {  // The app has been restarted.
 338             // Restore the visibility of the views.
 339             encryptionPasswordTextInputLayout.setVisibility(savedInstanceState.getInt(ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY));
 340             kitKatPasswordEncryptionTextView.setVisibility(savedInstanceState.getInt(KITKAT_PASSWORD_ENCRYPTED_TEXTVIEW_VISIBILITY));
 341             openKeychainRequiredTextView.setVisibility(savedInstanceState.getInt(OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY));
 342             fileLocationCardView.setVisibility(savedInstanceState.getInt(FILE_LOCATION_CARD_VIEW));
 343             fileNameLinearLayout.setVisibility(savedInstanceState.getInt(FILE_NAME_LINEARLAYOUT_VISIBILITY));
 344             openKeychainImportInstructionsTextView.setVisibility(savedInstanceState.getInt(OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY));
 345             importExportButton.setVisibility(savedInstanceState.getInt(IMPORT_EXPORT_BUTTON_VISIBILITY));
 346
 347             // Restore the text.
 348             fileNameEditText.post(() -> fileNameEditText.setText(savedInstanceState.getString(FILE_NAME_TEXT)));
 349             importExportButton.setText(savedInstanceState.getString(IMPORT_EXPORT_BUTTON_TEXT));
 350         }
 351     }
 352
 353     @Override
 354     public void onSaveInstanceState (@NonNull Bundle savedInstanceState) {
 355         // Run the default commands.
 356         super.onSaveInstanceState(savedInstanceState);
 357
 358         // Save the visibility of the views.
 359         savedInstanceState.putInt(ENCRYPTION_PASSWORD_TEXTINPUTLAYOUT_VISIBILITY, encryptionPasswordTextInputLayout.getVisibility());
 360         savedInstanceState.putInt(KITKAT_PASSWORD_ENCRYPTED_TEXTVIEW_VISIBILITY, kitKatPasswordEncryptionTextView.getVisibility());
 361         savedInstanceState.putInt(OPEN_KEYCHAIN_REQUIRED_TEXTVIEW_VISIBILITY, openKeychainRequiredTextView.getVisibility());
 362         savedInstanceState.putInt(FILE_LOCATION_CARD_VIEW, fileLocationCardView.getVisibility());
 363         savedInstanceState.putInt(FILE_NAME_LINEARLAYOUT_VISIBILITY, fileNameLinearLayout.getVisibility());
 364         savedInstanceState.putInt(OPEN_KEYCHAIN_IMPORT_INSTRUCTIONS_TEXTVIEW_VISIBILITY, openKeychainImportInstructionsTextView.getVisibility());
 365         savedInstanceState.putInt(IMPORT_EXPORT_BUTTON_VISIBILITY, importExportButton.getVisibility());
 366
 367         // Save the text.
 368         savedInstanceState.putString(FILE_NAME_TEXT, fileNameEditText.getText().toString());
 369         savedInstanceState.putString(IMPORT_EXPORT_BUTTON_TEXT, importExportButton.getText().toString());
 370     }
 371
 372     public void onClickRadioButton(View view) {
 373         // Get the current file name.
 374         String fileNameString = fileNameEditText.getText().toString();
 375
 376         // Convert the file name string to a file.
 377         File file = new File(fileNameString);
 378
 379         // Check to see if import or export was selected.
 380         if (view.getId() == R.id.import_radiobutton) {  // The import radio button is selected.
 381             // Check to see if OpenPGP encryption is selected.
 382             if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 383                 // Show the OpenKeychain import instructions.
 384                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 385
 386                 // Set the text on the import/export button to be `Decrypt`.
 387                 importExportButton.setText(R.string.decrypt);
 388             } else {  // OpenPGP encryption not selected.
 389                 // Hide the OpenKeychain import instructions.
 390                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 391
 392                 // Set the text on the import/export button to be `Import`.
 393                 importExportButton.setText(R.string.import_button);
 394             }
 395
 396             // Display the file name views.
 397             fileNameLinearLayout.setVisibility(View.VISIBLE);
 398             importExportButton.setVisibility(View.VISIBLE);
 399
 400             // Check to see if the file exists.
 401             if (file.exists()) {  // The file exists.
 402                 // Check to see if password encryption is selected.
 403                 if (encryptionSpinner.getSelectedItemPosition() == PASSWORD_ENCRYPTION) {  // Password encryption is selected.
 404                     // Enable the import button if the encryption password is populated.
 405                     importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 406                 } else {  // Password encryption is not selected.
 407                     // Enable the import/decrypt button.
 408                     importExportButton.setEnabled(true);
 409                 }
 410             } else {  // The file does not exist.
 411                 // Disable the import/decrypt button.
 412                 importExportButton.setEnabled(false);
 413             }
 414         } else {  // The export radio button is selected.
 415             // Hide the OpenKeychain import instructions.
 416             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 417
 418             // Set the text on the import/export button to be `Export`.
 419             importExportButton.setText(R.string.export);
 420
 421             // Show the import/export button.
 422             importExportButton.setVisibility(View.VISIBLE);
 423
 424             // Check to see if OpenPGP encryption is selected.
 425             if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 426                 // Hide the file name views.
 427                 fileNameLinearLayout.setVisibility(View.GONE);
 428
 429                 // Enable the export button.
 430                 importExportButton.setEnabled(true);
 431             } else {  // OpenPGP encryption is not selected.
 432                 // Show the file name view.
 433                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 434
 435                 // Check the encryption type.
 436                 if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 437                     // Enable the export button if the file name is populated.
 438                     importExportButton.setEnabled(!fileNameString.isEmpty());
 439                 } else {  // Password encryption is selected.
 440                     // Enable the export button if the file name and the password are populated.
 441                     importExportButton.setEnabled(!fileNameString.isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 442                 }
 443             }
 444         }
 445     }
 446
 447     public void browse(View view) {
 448         // Check to see if import or export is selected.
 449         if (importRadioButton.isChecked()) {  // Import is selected.
 450             // Create the file picker intent.
 451             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 452
 453             // Set the intent MIME type to include all files so that everything is visible.
 454             importBrowseIntent.setType("*/*");
 455
 456             // Request a file that can be opened.
 457             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 458
 459             // Launch the file picker.
 460             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 461         } else {  // Export is selected
 462             // Create the file picker intent.
 463             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 464
 465             // Set the intent MIME type to include all files so that everything is visible.
 466             exportBrowseIntent.setType("*/*");
 467
 468             // Set the initial export file name according to the encryption type.
 469             if (encryptionSpinner.getSelectedItemPosition() == NO_ENCRYPTION) {  // No encryption is selected.
 470                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs");
 471             } else {  // Password encryption is selected.
 472                 exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs.aes");
 473             }
 474
 475             // Request a file that can be opened.
 476             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 477
 478             // Launch the file picker.
 479             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 480         }
 481     }
 482
 483     @Override
 484     public void onActivityResult(int requestCode, int resultCode, Intent returnedIntent) {
 485         // Run the default commands.
 486         super.onActivityResult(requestCode, resultCode, returnedIntent);
 487
 488         switch (requestCode) {
 489             case (BROWSE_RESULT_CODE):
 490                 // Only do something if the user didn't press back from the file picker.
 491                 if (resultCode == Activity.RESULT_OK) {
 492                     // Get the file path URI from the intent.
 493                     Uri fileNameUri = returnedIntent.getData();
 494
 495                     // Get the file name string from the URI.
 496                     String fileNameString = fileNameUri.toString();
 497
 498                     // Set the file name name text.
 499                     fileNameEditText.setText(fileNameString);
 500
 501                     // Move the cursor to the end of the file name edit text.
 502                     fileNameEditText.setSelection(fileNameString.length());
 503                 }
 504                 break;
 505
 506             case OPENPGP_IMPORT_RESULT_CODE:
 507                 // Delete the temporary PGP encrypted import file.
 508                 if (temporaryPgpEncryptedImportFile.exists()) {
 509                     //noinspection ResultOfMethodCallIgnored
 510                     temporaryPgpEncryptedImportFile.delete();
 511                 }
 512                 break;
 513
 514             case OPENPGP_EXPORT_RESULT_CODE:
 515                 // Delete the temporary pre-encrypted export file if it exists.
 516                 if (temporaryPreEncryptedExportFile.exists()) {
 517                     //noinspection ResultOfMethodCallIgnored
 518                     temporaryPreEncryptedExportFile.delete();
 519                 }
 520                 break;
 521         }
 522     }
 523
 524     public void importExport(View view) {
 525         // Instantiate the import export database helper.
 526         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 527
 528         // Check to see if import or export is selected.
 529         if (importRadioButton.isChecked()) {  // Import is selected.
 530             // Initialize the import status string
 531             String importStatus = "";
 532
 533             // Get the file name string.
 534             String fileNameString = fileNameEditText.getText().toString();
 535
 536             // Import according to the encryption type.
 537             switch (encryptionSpinner.getSelectedItemPosition()) {
 538                 case NO_ENCRYPTION:
 539                     try {
 540                         // Get an input stream for the file name.
 541                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 542
 543                         // Import the unencrypted file.
 544                         importStatus = importExportDatabaseHelper.importUnencrypted(inputStream, this);
 545                     } catch (FileNotFoundException exception) {
 546                         // Update the import status.
 547                         importStatus = exception.toString();
 548                     }
 549
 550                     // Restart Privacy Browser if successful.
 551                     if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 552                         restartPrivacyBrowser();
 553                     }
 554                     break;
 555
 556                 case PASSWORD_ENCRYPTION:
 557                     try {
 558                         // Get the encryption password.
 559                         String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 560
 561                         // Get an input stream for the file name.
 562                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 563
 564                         // Get the salt from the beginning of the import file.
 565                         byte[] saltByteArray = new byte[32];
 566                         //noinspection ResultOfMethodCallIgnored
 567                         inputStream.read(saltByteArray);
 568
 569                         // Get the initialization vector from the import file.
 570                         byte[] initializationVector = new byte[12];
 571                         //noinspection ResultOfMethodCallIgnored
 572                         inputStream.read(initializationVector);
 573
 574                         // Convert the encryption password to a byte array.
 575                         byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 576
 577                         // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 578                         byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 579                         System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 580                         System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 581
 582                         // Get a SHA-512 message digest.
 583                         MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 584
 585                         // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 586                         byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 587
 588                         // Truncate the encryption password byte array to 256 bits (32 bytes).
 589                         byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 590
 591                         // Create an AES secret key from the encryption password byte array.
 592                         SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 593
 594                         // 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.
 595                         Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 596
 597                         // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 598                         GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 599
 600                         // Initialize the cipher.
 601                         cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 602
 603                         // Create a cipher input stream.
 604                         CipherInputStream cipherInputStream = new CipherInputStream(inputStream, cipher);
 605
 606                         // 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.
 607                         int numberOfBytesRead;
 608                         byte[] decryptedBytes = new byte[16];
 609
 610
 611                         // Create a private temporary unencrypted import file.
 612                         File temporaryUnencryptedImportFile = File.createTempFile("temporary_unencrypted_import_file", null, getApplicationContext().getCacheDir());
 613
 614                         // Create an temporary unencrypted import file output stream.
 615                         FileOutputStream temporaryUnencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 616
 617
 618                         // 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.
 619                         while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 620                             // Write the data to the temporary unencrypted import file output stream.
 621                             temporaryUnencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 622                         }
 623
 624
 625                         // Flush the temporary unencrypted import file output stream.
 626                         temporaryUnencryptedImportFileOutputStream.flush();
 627
 628                         // Close the streams.
 629                         temporaryUnencryptedImportFileOutputStream.close();
 630                         cipherInputStream.close();
 631                         inputStream.close();
 632
 633                         // Wipe the encryption data from memory.
 634                         //noinspection UnusedAssignment
 635                         encryptionPasswordString = "";
 636                         Arrays.fill(saltByteArray, (byte) 0);
 637                         Arrays.fill(initializationVector, (byte) 0);
 638                         Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 639                         Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 640                         Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 641                         Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 642                         Arrays.fill(decryptedBytes, (byte) 0);
 643
 644                         // Create a temporary unencrypted import file input stream.
 645                         FileInputStream temporaryUnencryptedImportFileInputStream = new FileInputStream(temporaryUnencryptedImportFile);
 646
 647                         // Import the temporary unencrypted import file.
 648                         importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFileInputStream, this);
 649
 650                         // Close the temporary unencrypted import file input stream.
 651                         temporaryUnencryptedImportFileInputStream.close();
 652
 653                         // Delete the temporary unencrypted import file.
 654                         //noinspection ResultOfMethodCallIgnored
 655                         temporaryUnencryptedImportFile.delete();
 656
 657                         // Restart Privacy Browser if successful.
 658                         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 659                             restartPrivacyBrowser();
 660                         }
 661                     } catch (Exception exception) {
 662                         // Update the import status.
 663                         importStatus = exception.toString();
 664                     }
 665                     break;
 666
 667                 case OPENPGP_ENCRYPTION:
 668                     try {
 669                         // Set the temporary PGP encrypted import file.
 670                         temporaryPgpEncryptedImportFile = File.createTempFile("temporary_pgp_encrypted_import_file", null, getApplicationContext().getCacheDir());
 671
 672                         // Create a temporary PGP encrypted import file output stream.
 673                         FileOutputStream temporaryPgpEncryptedImportFileOutputStream = new FileOutputStream(temporaryPgpEncryptedImportFile);
 674
 675                         // Get an input stream for the file name.
 676                         InputStream inputStream = getContentResolver().openInputStream(Uri.parse(fileNameString));
 677
 678                         // Create a transfer byte array.
 679                         byte[] transferByteArray = new byte[1024];
 680
 681                         // Create an integer to track the number of bytes read.
 682                         int bytesRead;
 683
 684                         // Copy the input stream to the temporary PGP encrypted import file.
 685                         while ((bytesRead = inputStream.read(transferByteArray)) > 0) {
 686                             temporaryPgpEncryptedImportFileOutputStream.write(transferByteArray, 0, bytesRead);
 687                         }
 688
 689                         // Flush the temporary PGP encrypted import file output stream.
 690                         temporaryPgpEncryptedImportFileOutputStream.flush();
 691
 692                         // Close the streams.
 693                         inputStream.close();
 694                         temporaryPgpEncryptedImportFileOutputStream.close();
 695
 696                         // Create an decryption intent for OpenKeychain.
 697                         Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 698
 699                         // Include the URI to be decrypted.
 700                         openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryPgpEncryptedImportFile));
 701
 702                         // Allow OpenKeychain to read the file URI.
 703                         openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 704
 705                         // Send the intent to the OpenKeychain package.
 706                         openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 707
 708                         // Make it so.
 709                         startActivityForResult(openKeychainDecryptIntent, OPENPGP_IMPORT_RESULT_CODE);
 710
 711                         // Update the import status.
 712                         importStatus = ImportExportDatabaseHelper.IMPORT_SUCCESSFUL;
 713                     } catch (Exception exception) {
 714                         // Update the import status.
 715                         importStatus = exception.toString();
 716                     }
 717                     break;
 718             }
 719
 720             // Respond to the import status.
 721             if (!importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {
 722                 // Display a snack bar with the import error.
 723                 Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 724             }
 725         } else {  // Export is selected.
 726             // Export according to the encryption type.
 727             switch (encryptionSpinner.getSelectedItemPosition()) {
 728                 case NO_ENCRYPTION:
 729                     // Get the file name string.
 730                     String noEncryptionFileNameString = fileNameEditText.getText().toString();
 731
 732                     try {
 733                         // Get the export file output stream.
 734                         OutputStream exportFileOutputStream = getContentResolver().openOutputStream(Uri.parse(noEncryptionFileNameString));
 735
 736                         // Export the unencrypted file.
 737                         String noEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(exportFileOutputStream, this);
 738
 739                         // Display an export disposition snackbar.
 740                         if (noEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 741                             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 742                         } else {
 743                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + noEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 744                         }
 745                     } catch (FileNotFoundException fileNotFoundException) {
 746                         // Display a snackbar with the exception.
 747                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + fileNotFoundException, Snackbar.LENGTH_INDEFINITE).show();
 748                     }
 749                     break;
 750
 751                 case PASSWORD_ENCRYPTION:
 752                     try {
 753                         // Create a temporary unencrypted export file.
 754                         File temporaryUnencryptedExportFile = File.createTempFile("temporary_unencrypted_export_file", null, getApplicationContext().getCacheDir());
 755
 756                         // Create a temporary unencrypted export output stream.
 757                         FileOutputStream temporaryUnencryptedExportOutputStream = new FileOutputStream(temporaryUnencryptedExportFile);
 758
 759                         // Populate the temporary unencrypted export.
 760                         String passwordEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportOutputStream, this);
 761
 762                         // Close the temporary unencrypted export output stream.
 763                         temporaryUnencryptedExportOutputStream.close();
 764
 765                         // Create an unencrypted export file input stream.
 766                         FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 767
 768                         // Get the encryption password.
 769                         String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 770
 771                         // Initialize a secure random number generator.
 772                         SecureRandom secureRandom = new SecureRandom();
 773
 774                         // Get a 256 bit (32 byte) random salt.
 775                         byte[] saltByteArray = new byte[32];
 776                         secureRandom.nextBytes(saltByteArray);
 777
 778                         // Convert the encryption password to a byte array.
 779                         byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 780
 781                         // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 782                         byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 783                         System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 784                         System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 785
 786                         // Get a SHA-512 message digest.
 787                         MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 788
 789                         // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 790                         byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 791
 792                         // Truncate the encryption password byte array to 256 bits (32 bytes).
 793                         byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 794
 795                         // Create an AES secret key from the encryption password byte array.
 796                         SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 797
 798                         // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 799                         byte[] initializationVector = new byte[12];
 800                         secureRandom.nextBytes(initializationVector);
 801
 802                         // 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.
 803                         Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 804
 805                         // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 806                         GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 807
 808                         // Initialize the cipher.
 809                         cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 810
 811                         // Get the file name string.
 812                         String passwordEncryptionFileNameString = fileNameEditText.getText().toString();
 813
 814                         // Get the export file output stream.
 815                         OutputStream exportFileOutputStream = getContentResolver().openOutputStream(Uri.parse(passwordEncryptionFileNameString));
 816
 817                         // Add the salt and the initialization vector to the export file output stream.
 818                         exportFileOutputStream.write(saltByteArray);
 819                         exportFileOutputStream.write(initializationVector);
 820
 821                         // Create a cipher output stream.
 822                         CipherOutputStream cipherOutputStream = new CipherOutputStream(exportFileOutputStream, cipher);
 823
 824                         // 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.
 825                         int numberOfBytesRead;
 826                         byte[] encryptedBytes = new byte[16];
 827
 828                         // 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.
 829                         while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 830                             // Write the data to the cipher output stream.
 831                             cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 832                         }
 833
 834                         // Close the streams.
 835                         cipherOutputStream.flush();
 836                         cipherOutputStream.close();
 837                         exportFileOutputStream.close();
 838                         unencryptedExportFileInputStream.close();
 839
 840                         // Wipe the encryption data from memory.
 841                         //noinspection UnusedAssignment
 842                         encryptionPasswordString = "";
 843                         Arrays.fill(saltByteArray, (byte) 0);
 844                         Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 845                         Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 846                         Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 847                         Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 848                         Arrays.fill(initializationVector, (byte) 0);
 849                         Arrays.fill(encryptedBytes, (byte) 0);
 850
 851                         // Delete the temporary unencrypted export file.
 852                         //noinspection ResultOfMethodCallIgnored
 853                         temporaryUnencryptedExportFile.delete();
 854
 855                         // Display an export disposition snackbar.
 856                         if (passwordEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 857                             Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 858                         } else {
 859                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + passwordEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 860                         }
 861                     } catch (Exception exception) {
 862                         // Display a snackbar with the exception.
 863                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
 864                     }
 865                     break;
 866
 867                 case OPENPGP_ENCRYPTION:
 868                     try {
 869                         // Set the temporary pre-encrypted export file.
 870                         temporaryPreEncryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.settings) + " " + BuildConfig.VERSION_NAME + ".pbs");
 871
 872                         // Delete the temporary pre-encrypted export file if it already exists.
 873                         if (temporaryPreEncryptedExportFile.exists()) {
 874                             //noinspection ResultOfMethodCallIgnored
 875                             temporaryPreEncryptedExportFile.delete();
 876                         }
 877
 878                         // Create a temporary pre-encrypted export output stream.
 879                         FileOutputStream temporaryPreEncryptedExportOutputStream = new FileOutputStream(temporaryPreEncryptedExportFile);
 880
 881                         // Populate the temporary pre-encrypted export file.
 882                         String openpgpEncryptionExportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryPreEncryptedExportOutputStream, this);
 883
 884                         // Flush the temporary pre-encryption export output stream.
 885                         temporaryPreEncryptedExportOutputStream.flush();
 886
 887                         // Close the temporary pre-encryption export output stream.
 888                         temporaryPreEncryptedExportOutputStream.close();
 889
 890                         // Display an export error snackbar if the temporary pre-encrypted export failed.
 891                         if (!openpgpEncryptionExportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 892                             Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + openpgpEncryptionExportStatus, Snackbar.LENGTH_INDEFINITE).show();
 893                         }
 894
 895                         // Create an encryption intent for OpenKeychain.
 896                         Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 897
 898                         // Include the temporary unencrypted export file URI.
 899                         openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryPreEncryptedExportFile));
 900
 901                         // Allow OpenKeychain to read the file URI.
 902                         openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 903
 904                         // Send the intent to the OpenKeychain package.
 905                         openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 906
 907                         // Make it so.
 908                         startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 909                     } catch (Exception exception) {
 910                         // Display a snackbar with the exception.
 911                         Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exception, Snackbar.LENGTH_INDEFINITE).show();
 912                     }
 913                     break;
 914             }
 915         }
 916     }
 917
 918     private void restartPrivacyBrowser() {
 919         // Create an intent to restart Privacy Browser.
 920         Intent restartIntent = getParentActivityIntent();
 921
 922         // Assert that the intent is not null to remove the lint error below.
 923         assert restartIntent != null;
 924
 925         // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 926         restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 927
 928         // Create a restart handler.
 929         Handler restartHandler = new Handler();
 930
 931         // Create a restart runnable.
 932         Runnable restartRunnable =  () -> {
 933             // Restart Privacy Browser.
 934             startActivity(restartIntent);
 935
 936             // Kill this instance of Privacy Browser.  Otherwise, the app exhibits sporadic behavior after the restart.
 937             System.exit(0);
 938         };
 939
 940         // Restart Privacy Browser after 150 milliseconds to allow enough time for the preferences to be saved.
 941         restartHandler.postDelayed(restartRunnable, 150);
 942     }
 943 }