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