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

   1 /*
   2  * Copyright © 2018-2019 Soren Stoutner <soren@stoutner.com>.
   3  *
   4  * This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
   5  *
   6  * Privacy Browser is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * Privacy Browser is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with Privacy Browser.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 package com.stoutner.privacybrowser.activities;
  21
  22 import android.Manifest;
  23 import android.app.Activity;
  24 import android.app.DialogFragment;
  25 import android.content.Intent;
  26 import android.content.pm.PackageManager;
  27 import android.net.Uri;
  28 import android.os.Build;
  29 import android.os.Bundle;
  30 import android.os.Environment;
  31 import android.provider.DocumentsContract;
  32 import android.support.annotation.NonNull;
  33 import android.support.design.widget.Snackbar;
  34 import android.support.design.widget.TextInputLayout;
  35 import android.support.v4.app.ActivityCompat;
  36 import android.support.v4.content.ContextCompat;
  37 import android.support.v4.content.FileProvider;
  38 import android.support.v7.app.ActionBar;
  39 import android.support.v7.app.AppCompatActivity;
  40 import android.support.v7.widget.CardView;
  41 import android.support.v7.widget.Toolbar;
  42 import android.text.Editable;
  43 import android.text.TextWatcher;
  44 import android.view.View;
  45 import android.view.WindowManager;
  46 import android.widget.AdapterView;
  47 import android.widget.ArrayAdapter;
  48 import android.widget.Button;
  49 import android.widget.EditText;
  50 import android.widget.LinearLayout;
  51 import android.widget.RadioButton;
  52 import android.widget.Spinner;
  53 import android.widget.TextView;
  54
  55 import com.stoutner.privacybrowser.R;
  56 import com.stoutner.privacybrowser.dialogs.ImportExportStoragePermissionDialog;
  57 import com.stoutner.privacybrowser.helpers.ImportExportDatabaseHelper;
  58
  59 import java.io.File;
  60 import java.io.FileInputStream;
  61 import java.io.FileOutputStream;
  62 import java.nio.charset.StandardCharsets;
  63 import java.security.MessageDigest;
  64 import java.security.SecureRandom;
  65 import java.util.Arrays;
  66
  67 import javax.crypto.Cipher;
  68 import javax.crypto.CipherInputStream;
  69 import javax.crypto.CipherOutputStream;
  70 import javax.crypto.spec.GCMParameterSpec;
  71 import javax.crypto.spec.SecretKeySpec;
  72
  73 public class ImportExportActivity extends AppCompatActivity implements ImportExportStoragePermissionDialog.ImportExportStoragePermissionDialogListener {
  74     // Create the encryption constants.
  75     private final int NO_ENCRYPTION = 0;
  76     private final int PASSWORD_ENCRYPTION = 1;
  77     private final int OPENPGP_ENCRYPTION = 2;
  78
  79     // Create the activity result constants.
  80     private final int BROWSE_RESULT_CODE = 0;
  81     private final int OPENPGP_EXPORT_RESULT_CODE = 1;
  82
  83     // `openKeychainInstalled` is accessed from an inner class.
  84     boolean openKeychainInstalled;
  85
  86     @Override
  87     public void onCreate(Bundle savedInstanceState) {
  88         // Disable screenshots if not allowed.
  89         if (!MainWebViewActivity.allowScreenshots) {
  90             getWindow().addFlags(WindowManager.LayoutParams.FLAG_SECURE);
  91         }
  92
  93         // Set the activity theme.
  94         if (MainWebViewActivity.darkTheme) {
  95             setTheme(R.style.PrivacyBrowserDark_SecondaryActivity);
  96         } else {
  97             setTheme(R.style.PrivacyBrowserLight_SecondaryActivity);
  98         }
  99
 100         // Run the default commands.
 101         super.onCreate(savedInstanceState);
 102
 103         // Set the content view.
 104         setContentView(R.layout.import_export_coordinatorlayout);
 105
 106         // Use the `SupportActionBar` from `android.support.v7.app.ActionBar` until the minimum API is >= 21.
 107         Toolbar importExportAppBar = findViewById(R.id.import_export_toolbar);
 108         setSupportActionBar(importExportAppBar);
 109
 110         // Display the home arrow on the support action bar.
 111         ActionBar appBar = getSupportActionBar();
 112         assert appBar != null;// This assert removes the incorrect warning in Android Studio on the following line that `appBar` might be null.
 113         appBar.setDisplayHomeAsUpEnabled(true);
 114
 115         // Find out if we are running KitKat
 116         boolean runningKitKat = (Build.VERSION.SDK_INT == 19);
 117
 118         // Find out if OpenKeychain is installed.
 119         try {
 120             openKeychainInstalled = !getPackageManager().getPackageInfo("org.sufficientlysecure.keychain", 0).versionName.isEmpty();
 121         } catch (PackageManager.NameNotFoundException exception) {
 122             openKeychainInstalled = false;
 123         }
 124
 125         // Get handles for the views that need to be modified.
 126         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 127         TextInputLayout passwordEncryptionTextInputLayout = findViewById(R.id.password_encryption_textinputlayout);
 128         EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 129         TextView kitKatPasswordEncryptionTextView = findViewById(R.id.kitkat_password_encryption_textview);
 130         TextView openKeychainRequiredTextView = findViewById(R.id.openkeychain_required_textview);
 131         CardView fileLocationCardView = findViewById(R.id.file_location_cardview);
 132         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 133         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 134         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 135         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 136         TextView openKeychainImportInstructionsTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 137         Button importExportButton = findViewById(R.id.import_export_button);
 138         TextView storagePermissionTextView = findViewById(R.id.import_export_storage_permission_textview);
 139
 140         // Create an array adapter for the spinner.
 141         ArrayAdapter<CharSequence> encryptionArrayAdapter = ArrayAdapter.createFromResource(this, R.array.encryption_type, R.layout.spinner_item);
 142
 143         // Set the drop down view resource on the spinner.
 144         encryptionArrayAdapter.setDropDownViewResource(R.layout.spinner_dropdown_items);
 145
 146         // Set the array adapter for the spinner.
 147         encryptionSpinner.setAdapter(encryptionArrayAdapter);
 148
 149         // Initially hide the unneeded views.
 150         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 151         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 152         openKeychainRequiredTextView.setVisibility(View.GONE);
 153         fileNameLinearLayout.setVisibility(View.GONE);
 154         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 155         importExportButton.setVisibility(View.GONE);
 156
 157         // Create strings for the default file paths.
 158         String defaultFilePath;
 159         String defaultPasswordEncryptionFilePath;
 160
 161         // Set the default file paths according to the storage permission status.
 162         if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 163             // Set the default file paths to use the external public directory.
 164             defaultFilePath = Environment.getExternalStorageDirectory() + "/" + getString(R.string.privacy_browser_settings);
 165             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 166         } else {  // The storage permission has not been granted.
 167             // Set the default file paths to use the external private directory.
 168             defaultFilePath = getApplicationContext().getExternalFilesDir(null) + "/" + getString(R.string.privacy_browser_settings);
 169             defaultPasswordEncryptionFilePath = defaultFilePath + ".aes";
 170         }
 171
 172         // Set the default file path.
 173         fileNameEditText.setText(defaultFilePath);
 174
 175         // Display the encryption information when the spinner changes.
 176         encryptionSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
 177             @Override
 178             public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
 179                 switch (position) {
 180                     case NO_ENCRYPTION:
 181                         // Hide the unneeded layout items.
 182                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 183                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 184                         openKeychainRequiredTextView.setVisibility(View.GONE);
 185                         openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 186
 187                         // Show the file location card.
 188                         fileLocationCardView.setVisibility(View.VISIBLE);
 189
 190                         // Show the file name linear layout if either import or export is checked.
 191                         if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 192                             fileNameLinearLayout.setVisibility(View.VISIBLE);
 193                         }
 194
 195                         // Reset the text of the import button, which may have been changed to `Decrypt`.
 196                         if (importRadioButton.isChecked()) {
 197                             importExportButton.setText(R.string.import_button);
 198                         }
 199
 200                         // Reset the default file path.
 201                         fileNameEditText.setText(defaultFilePath);
 202
 203                         // Enable the import/export button if a file name exists.
 204                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 205                         break;
 206
 207                     case PASSWORD_ENCRYPTION:
 208                         if (runningKitKat) {
 209                             // Show the KitKat password encryption message.
 210                             kitKatPasswordEncryptionTextView.setVisibility(View.VISIBLE);
 211
 212                             // Hide the OpenPGP required text view and the file location card.
 213                             openKeychainRequiredTextView.setVisibility(View.GONE);
 214                             fileLocationCardView.setVisibility(View.GONE);
 215                         } else {
 216                             // Hide the OpenPGP layout items.
 217                             openKeychainRequiredTextView.setVisibility(View.GONE);
 218                             openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 219
 220                             // Show the password encryption layout items.
 221                             passwordEncryptionTextInputLayout.setVisibility(View.VISIBLE);
 222
 223                             // Show the file location card.
 224                             fileLocationCardView.setVisibility(View.VISIBLE);
 225
 226                             // Show the file name linear layout if either import or export is checked.
 227                             if (importRadioButton.isChecked() || exportRadioButton.isChecked()) {
 228                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 229                             }
 230
 231                             // Reset the text of the import button, which may have been changed to `Decrypt`.
 232                             if (importRadioButton.isChecked()) {
 233                                 importExportButton.setText(R.string.import_button);
 234                             }
 235
 236                             // Update the default file path.
 237                             fileNameEditText.setText(defaultPasswordEncryptionFilePath);
 238
 239                             // Enable the import/export button if a password exists.
 240                             importExportButton.setEnabled(!encryptionPasswordEditText.getText().toString().isEmpty());
 241                         }
 242                         break;
 243
 244                     case OPENPGP_ENCRYPTION:
 245                         // Hide the password encryption layout items.
 246                         passwordEncryptionTextInputLayout.setVisibility(View.GONE);
 247                         kitKatPasswordEncryptionTextView.setVisibility(View.GONE);
 248
 249                         // Updated items based on the installation status of OpenKeychain.
 250                         if (openKeychainInstalled) {  // OpenKeychain is installed.
 251                             // Remove the default file path.
 252                             fileNameEditText.setText("");
 253
 254                             // Show the file location card.
 255                             fileLocationCardView.setVisibility(View.VISIBLE);
 256
 257                             if (importRadioButton.isChecked()) {
 258                                 // Show the file name linear layout and the OpenKeychain import instructions.
 259                                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 260                                 openKeychainImportInstructionsTextView.setVisibility(View.VISIBLE);
 261
 262                                 // Set the text of the import button to be `Decrypt`.
 263                                 importExportButton.setText(R.string.decrypt);
 264
 265                                 // Disable the import/export button.  The user needs to select a file to import first.
 266                                 importExportButton.setEnabled(false);
 267                             } else if (exportRadioButton.isChecked()) {
 268                                 // Hide the file name linear layout and the OpenKeychain import instructions.
 269                                 fileNameLinearLayout.setVisibility(View.GONE);
 270                                 openKeychainImportInstructionsTextView.setVisibility(View.GONE);
 271
 272                                 // Enable the import/export button.
 273                                 importExportButton.setEnabled(true);
 274                             }
 275                         } else {  // OpenKeychain is not installed.
 276                             // Show the OpenPGP required layout item.
 277                             openKeychainRequiredTextView.setVisibility(View.VISIBLE);
 278
 279                             // Hide the file location card.
 280                             fileLocationCardView.setVisibility(View.GONE);
 281                         }
 282                         break;
 283                 }
 284             }
 285
 286             @Override
 287             public void onNothingSelected(AdapterView<?> parent) {
 288
 289             }
 290         });
 291
 292         // Update the status of the import/export button when the password changes.
 293         encryptionPasswordEditText.addTextChangedListener(new TextWatcher() {
 294             @Override
 295             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 296                 // Do nothing.
 297             }
 298
 299             @Override
 300             public void onTextChanged(CharSequence s, int start, int before, int count) {
 301                 // Do nothing.
 302             }
 303
 304             @Override
 305             public void afterTextChanged(Editable s) {
 306                 // Enable the import/export button if a file name and password exists.
 307                 importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 308             }
 309         });
 310
 311         // Update the status of the import/export button when the file name EditText changes.
 312         fileNameEditText.addTextChangedListener(new TextWatcher() {
 313             @Override
 314             public void beforeTextChanged(CharSequence s, int start, int count, int after) {
 315                 // Do nothing.
 316             }
 317
 318             @Override
 319             public void onTextChanged(CharSequence s, int start, int before, int count) {
 320                 // Do nothing.
 321             }
 322
 323             @Override
 324             public void afterTextChanged(Editable s) {
 325                 // Adjust the export button according to the encryption spinner position.
 326                 switch (encryptionSpinner.getSelectedItemPosition()) {
 327                     case NO_ENCRYPTION:
 328                         // Enable the import/export button if a file name exists.
 329                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 330                         break;
 331
 332                     case PASSWORD_ENCRYPTION:
 333                         // Enable the import/export button if a file name and password exists.
 334                         importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty() && !encryptionPasswordEditText.getText().toString().isEmpty());
 335                         break;
 336
 337                     case OPENPGP_ENCRYPTION:
 338                         // Enable the import/export button if OpenKeychain is installed and a file name exists.
 339                         importExportButton.setEnabled(openKeychainInstalled && !fileNameEditText.getText().toString().isEmpty());
 340                         break;
 341                 }
 342             }
 343         });
 344
 345         // Hide the storage permissions TextView on API < 23 as permissions on older devices are automatically granted.
 346         if (Build.VERSION.SDK_INT < 23) {
 347             storagePermissionTextView.setVisibility(View.GONE);
 348         }
 349     }
 350
 351     public void onClickRadioButton(View view) {
 352         // Get handles for the views.
 353         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 354         LinearLayout fileNameLinearLayout = findViewById(R.id.file_name_linearlayout);
 355         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 356         TextView openKeychainImportInstructionTextView = findViewById(R.id.openkeychain_import_instructions_textview);
 357         Button importExportButton = findViewById(R.id.import_export_button);
 358
 359         // Check to see if import or export was selected.
 360         switch (view.getId()) {
 361             case R.id.import_radiobutton:
 362                 // Check to see if OpenPGP encryption is selected.
 363                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption selected.
 364                     // Show the OpenKeychain import instructions.
 365                     openKeychainImportInstructionTextView.setVisibility(View.VISIBLE);
 366
 367                     // Set the text on the import/export button to be `Decrypt`.
 368                     importExportButton.setText(R.string.decrypt);
 369
 370                     // Enable the decrypt button if there is a file name.
 371                     importExportButton.setEnabled(!fileNameEditText.getText().toString().isEmpty());
 372                 } else {  // OpenPGP encryption not selected.
 373                     // Hide the OpenKeychain import instructions.
 374                     openKeychainImportInstructionTextView.setVisibility(View.GONE);
 375
 376                     // Set the text on the import/export button to be `Import`.
 377                     importExportButton.setText(R.string.import_button);
 378                 }
 379
 380                 // Display the file name views.
 381                 fileNameLinearLayout.setVisibility(View.VISIBLE);
 382                 importExportButton.setVisibility(View.VISIBLE);
 383                 break;
 384
 385             case R.id.export_radiobutton:
 386                 // Hide the OpenKeychain import instructions.
 387                 openKeychainImportInstructionTextView.setVisibility(View.GONE);
 388
 389                 // Set the text on the import/export button to be `Export`.
 390                 importExportButton.setText(R.string.export);
 391
 392                 // Show the import/export button.
 393                 importExportButton.setVisibility(View.VISIBLE);
 394
 395                 // Check to see if OpenPGP encryption is selected.
 396                 if (encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) {  // OpenPGP encryption is selected.
 397                     // Hide the file name views.
 398                     fileNameLinearLayout.setVisibility(View.GONE);
 399
 400                     // Enable the export button.
 401                     importExportButton.setEnabled(true);
 402                 } else {  // OpenPGP encryption is not selected.
 403                     // Show the file name views.
 404                     fileNameLinearLayout.setVisibility(View.VISIBLE);
 405                 }
 406                 break;
 407         }
 408     }
 409
 410     public void browse(View view) {
 411         // Get a handle for the import radiobutton.
 412         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 413
 414         // Check to see if import or export is selected.
 415         if (importRadioButton.isChecked()) {  // Import is selected.
 416             // Create the file picker intent.
 417             Intent importBrowseIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
 418
 419             // Set the intent MIME type to include all files.
 420             importBrowseIntent.setType("*/*");
 421
 422             // Set the initial directory if API >= 26.
 423             if (Build.VERSION.SDK_INT >= 26) {
 424                 importBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 425             }
 426
 427             // Specify that a file that can be opened is requested.
 428             importBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 429
 430             // Launch the file picker.
 431             startActivityForResult(importBrowseIntent, BROWSE_RESULT_CODE);
 432         } else {  // Export is selected
 433             // Create the file picker intent.
 434             Intent exportBrowseIntent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
 435
 436             // Set the intent MIME type to include all files.
 437             exportBrowseIntent.setType("*/*");
 438
 439             // Set the initial export file name.
 440             exportBrowseIntent.putExtra(Intent.EXTRA_TITLE, getString(R.string.privacy_browser_settings));
 441
 442             // Set the initial directory if API >= 26.
 443             if (Build.VERSION.SDK_INT >= 26) {
 444                 exportBrowseIntent.putExtra(DocumentsContract.EXTRA_INITIAL_URI, Environment.getExternalStorageDirectory());
 445             }
 446
 447             // Specify that a file that can be opened is requested.
 448             exportBrowseIntent.addCategory(Intent.CATEGORY_OPENABLE);
 449
 450             // Launch the file picker.
 451             startActivityForResult(exportBrowseIntent, BROWSE_RESULT_CODE);
 452         }
 453     }
 454
 455     public void importExport(View view) {
 456         // Get a handle for the views.
 457         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 458         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 459         RadioButton exportRadioButton = findViewById(R.id.export_radiobutton);
 460
 461         // Check to see if the storage permission is needed.
 462         if ((encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION) && exportRadioButton.isChecked()) {  // Permission not needed to export via OpenKeychain.
 463             // Export the settings.
 464             exportSettings();
 465         } else if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {  // The storage permission has been granted.
 466             // Check to see if import or export is selected.
 467             if (importRadioButton.isChecked()) {  // Import is selected.
 468                 // Import the settings.
 469                 importSettings();
 470             } else {  // Export is selected.
 471                 // Export the settings.
 472                 exportSettings();
 473             }
 474         } else {  // The storage permission has not been granted.
 475             // Get a handle for the file name EditText.
 476             EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 477
 478             // Get the file name string.
 479             String fileNameString = fileNameEditText.getText().toString();
 480
 481             // Get the external private directory `File`.
 482             File externalPrivateDirectoryFile = getApplicationContext().getExternalFilesDir(null);
 483
 484             // Remove the lint error below that the `File` might be null.
 485             assert externalPrivateDirectoryFile != null;
 486
 487             // Get the external private directory string.
 488             String externalPrivateDirectory = externalPrivateDirectoryFile.toString();
 489
 490             // Check to see if the file path is in the external private directory.
 491             if (fileNameString.startsWith(externalPrivateDirectory)) {  // The file path is in the external private directory.
 492                 // Check to see if import or export is selected.
 493                 if (importRadioButton.isChecked()) {  // Import is selected.
 494                     // Import the settings.
 495                     importSettings();
 496                 } else {  // Export is selected.
 497                     // Export the settings.
 498                     exportSettings();
 499                 }
 500             } else {  // The file path is in a public directory.
 501                 // Check if the user has previously denied the storage permission.
 502                 if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {  // Show a dialog explaining the request first.
 503                     // Instantiate the storage permission alert dialog.
 504                     DialogFragment importExportStoragePermissionDialogFragment = new ImportExportStoragePermissionDialog();
 505
 506                     // Show the storage permission alert dialog.  The permission will be requested when the dialog is closed.
 507                     importExportStoragePermissionDialogFragment.show(getFragmentManager(), getString(R.string.storage_permission));
 508                 } else {  // Show the permission request directly.
 509                     // Request the storage permission.  The export will be run when it finishes.
 510                     ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 511                 }
 512             }
 513         }
 514     }
 515
 516     @Override
 517     public void onCloseImportExportStoragePermissionDialog() {
 518         // Request the write external storage permission.  The import/export will be run when it finishes.
 519         ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.WRITE_EXTERNAL_STORAGE}, 0);
 520     }
 521
 522     @Override
 523     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
 524         // Get a handle for the import radiobutton.
 525         RadioButton importRadioButton = findViewById(R.id.import_radiobutton);
 526
 527         // Check to see if import or export is selected.
 528         if (importRadioButton.isChecked()) {  // Import is selected.
 529             // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 530             if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 531                 // Import the settings.
 532                 importSettings();
 533             } else {  // The storage permission was not granted.
 534                 // Display an error snackbar.
 535                 Snackbar.make(importRadioButton, getString(R.string.cannot_import), Snackbar.LENGTH_LONG).show();
 536             }
 537         } else {  // Export is selected.
 538             // Check to see if the storage permission was granted.  If the dialog was canceled the grant results will be empty.
 539             if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {  // The storage permission was granted.
 540                 // Export the settings.
 541                 exportSettings();
 542             } else {  // The storage permission was not granted.
 543                 // Display an error snackbar.
 544                 Snackbar.make(importRadioButton, getString(R.string.cannot_export), Snackbar.LENGTH_LONG).show();
 545             }
 546         }
 547     }
 548
 549     @Override
 550     public void onActivityResult(int requestCode, int resultCode, Intent data) {
 551         switch (requestCode) {
 552             case (BROWSE_RESULT_CODE):
 553                 // Don't do anything if the user pressed back from the file picker.
 554                 if (resultCode == Activity.RESULT_OK) {
 555                     // Get a handle for the file name EditText.
 556                     EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 557
 558                     // Get the file name URI.
 559                     Uri fileNameUri = data.getData();
 560
 561                     // Remove the lint warning that the file name URI might be null.
 562                     assert fileNameUri != null;
 563
 564                     // Get the raw file name path.
 565                     String rawFileNamePath = fileNameUri.getPath();
 566
 567                     // Remove the warning that the file name path might be null.
 568                     assert rawFileNamePath != null;
 569
 570                     // Check to see if the file name Path includes a valid storage location.
 571                     if (rawFileNamePath.contains(":")) {  // The path is valid.
 572                         // Split the path into the initial content uri and the final path information.
 573                         String fileNameContentPath = rawFileNamePath.substring(0, rawFileNamePath.indexOf(":"));
 574                         String fileNameFinalPath = rawFileNamePath.substring(rawFileNamePath.indexOf(":") + 1);
 575
 576                         // Create the file name path string.
 577                         String fileNamePath;
 578
 579                         // Construct the file name path.
 580                         switch (fileNameContentPath) {
 581                             // The documents home has a special content path.
 582                             case "/document/home":
 583                                 fileNamePath = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS) + "/" + fileNameFinalPath;
 584                                 break;
 585
 586                             // Everything else for the primary user should be in `/document/primary`.
 587                             case "/document/primary":
 588                                 fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 589                                 break;
 590
 591                             // Just in case, catch everything else and place it in the external storage directory.
 592                             default:
 593                                 fileNamePath = Environment.getExternalStorageDirectory() + "/" + fileNameFinalPath;
 594                                 break;
 595                         }
 596
 597                         // Set the file name path as the text of the file name EditText.
 598                         fileNameEditText.setText(fileNamePath);
 599                     } else {  // The path is invalid.
 600                         Snackbar.make(fileNameEditText, rawFileNamePath + " " + getString(R.string.invalid_location), Snackbar.LENGTH_INDEFINITE).show();
 601                     }
 602                 }
 603                 break;
 604
 605             case OPENPGP_EXPORT_RESULT_CODE:
 606                 // Get the temporary unencrypted export file.
 607                 File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.privacy_browser_settings));
 608
 609                 // Delete the temporary unencrypted export file if it exists.
 610                 if (temporaryUnencryptedExportFile.exists()) {
 611                     //noinspection ResultOfMethodCallIgnored
 612                     temporaryUnencryptedExportFile.delete();
 613                 }
 614                 break;
 615         }
 616     }
 617
 618     private void exportSettings() {
 619         // Get a handle for the views.
 620         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 621         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 622
 623         // Instantiate the import export database helper.
 624         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 625
 626         // Get the export and temporary unencrypted export files.
 627         File exportFile = new File(fileNameEditText.getText().toString());
 628         File temporaryUnencryptedExportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.privacy_browser_settings));
 629
 630         // Initialize the export status string.
 631         String exportStatus;
 632
 633         // Export according to the encryption type.
 634         switch (encryptionSpinner.getSelectedItemPosition()) {
 635             case NO_ENCRYPTION:
 636                 // Export the unencrypted file.
 637                 exportStatus = importExportDatabaseHelper.exportUnencrypted(exportFile, this);
 638
 639                 // Show a disposition snackbar.
 640                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 641                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 642                 } else {
 643                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 644                 }
 645                 break;
 646
 647             case PASSWORD_ENCRYPTION:
 648                 // Create an unencrypted export in a private directory.
 649                 exportStatus = importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 650
 651                 try {
 652                     // Create an unencrypted export file input stream.
 653                     FileInputStream unencryptedExportFileInputStream = new FileInputStream(temporaryUnencryptedExportFile);
 654
 655                     // Delete the encrypted export file if it exists.
 656                     if (exportFile.exists()) {
 657                         //noinspection ResultOfMethodCallIgnored
 658                         exportFile.delete();
 659                     }
 660
 661                     // Create an encrypted export file output stream.
 662                     FileOutputStream encryptedExportFileOutputStream = new FileOutputStream(exportFile);
 663
 664                     // Get a handle for the encryption password EditText.
 665                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 666
 667                     // Get the encryption password.
 668                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 669
 670                     // Initialize a secure random number generator.
 671                     SecureRandom secureRandom = new SecureRandom();
 672
 673                     // Get a 256 bit (32 byte) random salt.
 674                     byte[] saltByteArray = new byte[32];
 675                     secureRandom.nextBytes(saltByteArray);
 676
 677                     // Convert the encryption password to a byte array.
 678                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 679
 680                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 681                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 682                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 683                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 684
 685                     // Get a SHA-512 message digest.
 686                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 687
 688                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 689                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 690
 691                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 692                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 693
 694                     // Create an AES secret key from the encryption password byte array.
 695                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 696
 697                     // Generate a random 12 byte initialization vector.  According to NIST, a 12 byte initialization vector is more secure than a 16 byte one.
 698                     byte[] initializationVector = new byte[12];
 699                     secureRandom.nextBytes(initializationVector);
 700
 701                     // 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.
 702                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 703
 704                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 705                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 706
 707                     // Initialize the cipher.
 708                     cipher.init(Cipher.ENCRYPT_MODE, secretKey, gcmParameterSpec);
 709
 710                     // Add the salt and the initialization vector to the export file.
 711                     encryptedExportFileOutputStream.write(saltByteArray);
 712                     encryptedExportFileOutputStream.write(initializationVector);
 713
 714                     // Create a cipher output stream.
 715                     CipherOutputStream cipherOutputStream = new CipherOutputStream(encryptedExportFileOutputStream, cipher);
 716
 717                     // 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.
 718                     int numberOfBytesRead;
 719                     byte[] encryptedBytes = new byte[16];
 720
 721                     // 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.
 722                     while ((numberOfBytesRead = unencryptedExportFileInputStream.read(encryptedBytes)) != -1) {
 723                         // Write the data to the cipher output stream.
 724                         cipherOutputStream.write(encryptedBytes, 0, numberOfBytesRead);
 725                     }
 726
 727                     // Close the streams.
 728                     cipherOutputStream.flush();
 729                     cipherOutputStream.close();
 730                     encryptedExportFileOutputStream.close();
 731                     unencryptedExportFileInputStream.close();
 732
 733                     // Wipe the encryption data from memory.
 734                     //noinspection UnusedAssignment
 735                     encryptionPasswordString = "";
 736                     Arrays.fill(saltByteArray, (byte) 0);
 737                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 738                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 739                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 740                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 741                     Arrays.fill(initializationVector, (byte) 0);
 742                     Arrays.fill(encryptedBytes, (byte) 0);
 743
 744                     // Delete the temporary unencrypted export file.
 745                     //noinspection ResultOfMethodCallIgnored
 746                     temporaryUnencryptedExportFile.delete();
 747                 } catch (Exception exception) {
 748                     exportStatus = exception.toString();
 749                 }
 750
 751                 // Show a disposition snackbar.
 752                 if (exportStatus.equals(ImportExportDatabaseHelper.EXPORT_SUCCESSFUL)) {
 753                     Snackbar.make(fileNameEditText, getString(R.string.export_successful), Snackbar.LENGTH_SHORT).show();
 754                 } else {
 755                     Snackbar.make(fileNameEditText, getString(R.string.export_failed) + "  " + exportStatus, Snackbar.LENGTH_INDEFINITE).show();
 756                 }
 757                 break;
 758
 759             case OPENPGP_ENCRYPTION:
 760                 // Create an unencrypted export in the private location.
 761                 importExportDatabaseHelper.exportUnencrypted(temporaryUnencryptedExportFile, this);
 762
 763                 // Create an encryption intent for OpenKeychain.
 764                 Intent openKeychainEncryptIntent = new Intent("org.sufficientlysecure.keychain.action.ENCRYPT_DATA");
 765
 766                 // Include the temporary unencrypted export file URI.
 767                 openKeychainEncryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), temporaryUnencryptedExportFile));
 768
 769                 // Allow OpenKeychain to read the file URI.
 770                 openKeychainEncryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 771
 772                 // Send the intent to the OpenKeychain package.
 773                 openKeychainEncryptIntent.setPackage("org.sufficientlysecure.keychain");
 774
 775                 // Make it so.
 776                 startActivityForResult(openKeychainEncryptIntent, OPENPGP_EXPORT_RESULT_CODE);
 777                 break;
 778         }
 779     }
 780
 781     private void importSettings() {
 782         // Get a handle for the views.
 783         Spinner encryptionSpinner = findViewById(R.id.encryption_spinner);
 784         EditText fileNameEditText = findViewById(R.id.file_name_edittext);
 785
 786         // Instantiate the import export database helper.
 787         ImportExportDatabaseHelper importExportDatabaseHelper = new ImportExportDatabaseHelper();
 788
 789         // Get the import file.
 790         File importFile = new File(fileNameEditText.getText().toString());
 791
 792         // Initialize the import status string
 793         String importStatus = "";
 794
 795         // Import according to the encryption type.
 796         switch (encryptionSpinner.getSelectedItemPosition()) {
 797             case NO_ENCRYPTION:
 798                 // Import the unencrypted file.
 799                 importStatus = importExportDatabaseHelper.importUnencrypted(importFile, this);
 800                 break;
 801
 802             case PASSWORD_ENCRYPTION:
 803                 // Use a private temporary import location.
 804                 File temporaryUnencryptedImportFile = new File(getApplicationContext().getCacheDir() + "/" + getString(R.string.privacy_browser_settings));
 805
 806                 try {
 807                     // Create an encrypted import file input stream.
 808                     FileInputStream encryptedImportFileInputStream = new FileInputStream(importFile);
 809
 810                     // Delete the temporary import file if it exists.
 811                     if (temporaryUnencryptedImportFile.exists()) {
 812                         //noinspection ResultOfMethodCallIgnored
 813                         temporaryUnencryptedImportFile.delete();
 814                     }
 815
 816                     // Create an unencrypted import file output stream.
 817                     FileOutputStream unencryptedImportFileOutputStream = new FileOutputStream(temporaryUnencryptedImportFile);
 818
 819                     // Get a handle for the encryption password EditText.
 820                     EditText encryptionPasswordEditText = findViewById(R.id.password_encryption_edittext);
 821
 822                     // Get the encryption password.
 823                     String encryptionPasswordString = encryptionPasswordEditText.getText().toString();
 824
 825                     // Get the salt from the beginning of the import file.
 826                     byte[] saltByteArray = new byte[32];
 827                     //noinspection ResultOfMethodCallIgnored
 828                     encryptedImportFileInputStream.read(saltByteArray);
 829
 830                     // Get the initialization vector from the import file.
 831                     byte[] initializationVector = new byte[12];
 832                     //noinspection ResultOfMethodCallIgnored
 833                     encryptedImportFileInputStream.read(initializationVector);
 834
 835                     // Convert the encryption password to a byte array.
 836                     byte[] encryptionPasswordByteArray = encryptionPasswordString.getBytes(StandardCharsets.UTF_8);
 837
 838                     // Append the salt to the encryption password byte array.  This protects against rainbow table attacks.
 839                     byte[] encryptionPasswordWithSaltByteArray = new byte[encryptionPasswordByteArray.length + saltByteArray.length];
 840                     System.arraycopy(encryptionPasswordByteArray, 0, encryptionPasswordWithSaltByteArray, 0, encryptionPasswordByteArray.length);
 841                     System.arraycopy(saltByteArray, 0, encryptionPasswordWithSaltByteArray, encryptionPasswordByteArray.length, saltByteArray.length);
 842
 843                     // Get a SHA-512 message digest.
 844                     MessageDigest messageDigest = MessageDigest.getInstance("SHA-512");
 845
 846                     // Hash the salted encryption password.  Otherwise, any characters after the 32nd character in the password are ignored.
 847                     byte[] hashedEncryptionPasswordWithSaltByteArray = messageDigest.digest(encryptionPasswordWithSaltByteArray);
 848
 849                     // Truncate the encryption password byte array to 256 bits (32 bytes).
 850                     byte[] truncatedHashedEncryptionPasswordWithSaltByteArray = Arrays.copyOf(hashedEncryptionPasswordWithSaltByteArray, 32);
 851
 852                     // Create an AES secret key from the encryption password byte array.
 853                     SecretKeySpec secretKey = new SecretKeySpec(truncatedHashedEncryptionPasswordWithSaltByteArray, "AES");
 854
 855                     // 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.
 856                     Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
 857
 858                     // Set the GCM tag length to be 128 bits (the maximum) and apply the initialization vector.
 859                     GCMParameterSpec gcmParameterSpec = new GCMParameterSpec(128, initializationVector);
 860
 861                     // Initialize the cipher.
 862                     cipher.init(Cipher.DECRYPT_MODE, secretKey, gcmParameterSpec);
 863
 864                     // Create a cipher input stream.
 865                     CipherInputStream cipherInputStream = new CipherInputStream(encryptedImportFileInputStream, cipher);
 866
 867                     // 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.
 868                     int numberOfBytesRead;
 869                     byte[] decryptedBytes = new byte[16];
 870
 871                     // 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.
 872                     while ((numberOfBytesRead = cipherInputStream.read(decryptedBytes)) != -1) {
 873                         // Write the data to the unencrypted import file output stream.
 874                         unencryptedImportFileOutputStream.write(decryptedBytes, 0, numberOfBytesRead);
 875                     }
 876
 877                     // Close the streams.
 878                     unencryptedImportFileOutputStream.flush();
 879                     unencryptedImportFileOutputStream.close();
 880                     cipherInputStream.close();
 881                     encryptedImportFileInputStream.close();
 882
 883                     // Wipe the encryption data from memory.
 884                     //noinspection UnusedAssignment
 885                     encryptionPasswordString = "";
 886                     Arrays.fill(saltByteArray, (byte) 0);
 887                     Arrays.fill(initializationVector, (byte) 0);
 888                     Arrays.fill(encryptionPasswordByteArray, (byte) 0);
 889                     Arrays.fill(encryptionPasswordWithSaltByteArray, (byte) 0);
 890                     Arrays.fill(hashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 891                     Arrays.fill(truncatedHashedEncryptionPasswordWithSaltByteArray, (byte) 0);
 892                     Arrays.fill(decryptedBytes, (byte) 0);
 893
 894                     // Import the unencrypted database from the private location.
 895                     importStatus = importExportDatabaseHelper.importUnencrypted(temporaryUnencryptedImportFile, this);
 896
 897                     // Delete the temporary unencrypted import file.
 898                     //noinspection ResultOfMethodCallIgnored
 899                     temporaryUnencryptedImportFile.delete();
 900                 } catch (Exception exception) {
 901                     importStatus = exception.toString();
 902                 }
 903                 break;
 904
 905             case OPENPGP_ENCRYPTION:
 906                 try {
 907                     // Create an decryption intent for OpenKeychain.
 908                     Intent openKeychainDecryptIntent = new Intent("org.sufficientlysecure.keychain.action.DECRYPT_DATA");
 909
 910                     // Include the URI to be decrypted.
 911                     openKeychainDecryptIntent.setData(FileProvider.getUriForFile(this, getString(R.string.file_provider), importFile));
 912
 913                     // Allow OpenKeychain to read the file URI.
 914                     openKeychainDecryptIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
 915
 916                     // Send the intent to the OpenKeychain package.
 917                     openKeychainDecryptIntent.setPackage("org.sufficientlysecure.keychain");
 918
 919                     // Make it so.
 920                     startActivity(openKeychainDecryptIntent);
 921                 } catch (IllegalArgumentException exception) {  // The file import location is not valid.
 922                     // Display a snack bar with the import error.
 923                     Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + exception.toString(), Snackbar.LENGTH_INDEFINITE).show();
 924                 }
 925                 break;
 926         }
 927
 928         // Respond to the import disposition.
 929         if (importStatus.equals(ImportExportDatabaseHelper.IMPORT_SUCCESSFUL)) {  // The import was successful.
 930             // Create an intent to restart Privacy Browser.
 931             Intent restartIntent = getParentActivityIntent();
 932
 933             // Assert that the intent is not null to remove the lint error below.
 934             assert restartIntent != null;
 935
 936             // `Intent.FLAG_ACTIVITY_CLEAR_TASK` removes all activities from the stack.  It requires `Intent.FLAG_ACTIVITY_NEW_TASK`.
 937             restartIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
 938
 939             // Make it so.
 940             startActivity(restartIntent);
 941         } else if (!(encryptionSpinner.getSelectedItemPosition() == OPENPGP_ENCRYPTION)){  // The import was not successful.
 942             // Display a snack bar with the import error.
 943             Snackbar.make(fileNameEditText, getString(R.string.import_failed) + "  " + importStatus, Snackbar.LENGTH_INDEFINITE).show();
 944         }
 945     }
 946 }