askpassphrasedialog.cpp

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// Copyright (c) 2011-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif

#include <qt/askpassphrasedialog.h>
#include <qt/forms/ui_askpassphrasedialog.h>

#include <qt/guiconstants.h>
#include <qt/walletmodel.h>
#include <support/allocators/secure.h>

#include <QKeyEvent>
#include <QMessageBox>
#include <QPushButton>

AskPassphraseDialog::AskPassphraseDialog(Mode _mode, QWidget *parent,
                                         SecureString *passphrase_out)
    : QDialog(parent), ui(new Ui::AskPassphraseDialog), mode(_mode),
      model(nullptr), fCapsLock(false), m_passphrase_out(passphrase_out) {
    ui->setupUi(this);

    ui->passEdit1->setMinimumSize(ui->passEdit1->sizeHint());
    ui->passEdit2->setMinimumSize(ui->passEdit2->sizeHint());
    ui->passEdit3->setMinimumSize(ui->passEdit3->sizeHint());

    ui->passEdit1->setMaxLength(MAX_PASSPHRASE_SIZE);
    ui->passEdit2->setMaxLength(MAX_PASSPHRASE_SIZE);
    ui->passEdit3->setMaxLength(MAX_PASSPHRASE_SIZE);

    // Setup Caps Lock detection.
    ui->passEdit1->installEventFilter(this);
    ui->passEdit2->installEventFilter(this);
    ui->passEdit3->installEventFilter(this);

    switch (mode) {
        case Encrypt: // Ask passphrase x2
            ui->warningLabel->setText(
                tr("Enter the new passphrase for the wallet.<br/>Please use a "
                   "passphrase of <b>ten or more random characters</b>, or "
                   "<b>eight or more words</b>."));
            ui->passLabel1->hide();
            ui->passEdit1->hide();
            setWindowTitle(tr("Encrypt wallet"));
            break;
        case Unlock: // Ask passphrase
            ui->warningLabel->setText(tr("This operation needs your wallet "
                                         "passphrase to unlock the wallet."));
            ui->passLabel2->hide();
            ui->passEdit2->hide();
            ui->passLabel3->hide();
            ui->passEdit3->hide();
            setWindowTitle(tr("Unlock wallet"));
            break;
        case Decrypt: // Ask passphrase
            ui->warningLabel->setText(tr("This operation needs your wallet "
                                         "passphrase to decrypt the wallet."));
            ui->passLabel2->hide();
            ui->passEdit2->hide();
            ui->passLabel3->hide();
            ui->passEdit3->hide();
            setWindowTitle(tr("Decrypt wallet"));
            break;
        case ChangePass: // Ask old passphrase + new passphrase x2
            setWindowTitle(tr("Change passphrase"));
            ui->warningLabel->setText(tr(
                "Enter the old passphrase and new passphrase for the wallet."));
            break;
    }
    textChanged();
    connect(ui->toggleShowPasswordButton, &QPushButton::toggled, this,
            &AskPassphraseDialog::toggleShowPassword);
    connect(ui->passEdit1, &QLineEdit::textChanged, this,
            &AskPassphraseDialog::textChanged);
    connect(ui->passEdit2, &QLineEdit::textChanged, this,
            &AskPassphraseDialog::textChanged);
    connect(ui->passEdit3, &QLineEdit::textChanged, this,
            &AskPassphraseDialog::textChanged);
}

AskPassphraseDialog::~AskPassphraseDialog() {
    secureClearPassFields();
    delete ui;
}

void AskPassphraseDialog::setModel(WalletModel *_model) {
    this->model = _model;
}

void AskPassphraseDialog::accept() {
    SecureString oldpass, newpass1, newpass2;
    if (!model && mode != Encrypt) {
        return;
    }
    oldpass.reserve(MAX_PASSPHRASE_SIZE);
    newpass1.reserve(MAX_PASSPHRASE_SIZE);
    newpass2.reserve(MAX_PASSPHRASE_SIZE);
    // TODO: get rid of this .c_str() by implementing
    // SecureString::operator=(std::string)
    // Alternately, find a way to make this input mlock()'d to begin with.
    oldpass.assign(ui->passEdit1->text().toStdString().c_str());
    newpass1.assign(ui->passEdit2->text().toStdString().c_str());
    newpass2.assign(ui->passEdit3->text().toStdString().c_str());

    secureClearPassFields();

    switch (mode) {
        case Encrypt: {
            if (newpass1.empty() || newpass2.empty()) {
                // Cannot encrypt with empty passphrase
                break;
            }
            QMessageBox::StandardButton retval = QMessageBox::question(
                this, tr("Confirm wallet encryption"),
                tr("Warning: If you encrypt your wallet and lose your "
                   "passphrase, you will <b>LOSE ALL OF YOUR BITCOINS</b>!") +
                    "<br><br>" +
                    tr("Are you sure you wish to encrypt your wallet?"),
                QMessageBox::Yes | QMessageBox::Cancel, QMessageBox::Cancel);
            if (retval == QMessageBox::Yes) {
                if (newpass1 == newpass2) {
                    QString encryption_reminder =
                        tr("Remember that encrypting your wallet cannot fully "
                           "protect your bitcoins from being stolen by malware "
                           "infecting your computer.");
                    if (m_passphrase_out) {
                        m_passphrase_out->assign(newpass1);
                        QMessageBox::warning(
                            this, tr("Wallet to be encrypted"),
                            "<qt>" +
                                tr("Your wallet is about to be encrypted. ") +
                                encryption_reminder + "</b></qt>");
                    } else {
                        assert(model != nullptr);
                        if (model->setWalletEncrypted(true, newpass1)) {
                            QMessageBox::warning(
                                this, tr("Wallet encrypted"),
                                "<qt>" + tr("Your wallet is now encrypted. ") +
                                    encryption_reminder + "<br><br><b>" +
                                    tr("IMPORTANT: Any previous backups you "
                                       "have made of your wallet file should "
                                       "be replaced with the newly generated, "
                                       "encrypted wallet file. For security "
                                       "reasons, previous backups of the "
                                       "unencrypted wallet file will become "
                                       "useless as soon as you start using the "
                                       "new, encrypted wallet.") +
                                    "</b></qt>");
                        } else {
                            QMessageBox::critical(
                                this, tr("Wallet encryption failed"),
                                tr("Wallet encryption failed due to an "
                                   "internal error. Your wallet was not "
                                   "encrypted."));
                        }
                    }
                    QDialog::accept(); // Success
                } else {
                    QMessageBox::critical(
                        this, tr("Wallet encryption failed"),
                        tr("The supplied passphrases do not match."));
                }
            } else {
                QDialog::reject(); // Cancelled
            }
        } break;
        case Unlock:
            try {
                if (!model->setWalletLocked(false, oldpass)) {
                    QMessageBox::critical(
                        this, tr("Wallet unlock failed"),
                        tr("The passphrase entered for the wallet decryption "
                           "was incorrect."));
                } else {
                    // Success
                    QDialog::accept();
                }
            } catch (const std::runtime_error &e) {
                QMessageBox::critical(this, tr("Wallet unlock failed"),
                                      e.what());
            }
            break;
        case Decrypt:
            if (!model->setWalletEncrypted(false, oldpass)) {
                QMessageBox::critical(this, tr("Wallet decryption failed"),
                                      tr("The passphrase entered for the "
                                         "wallet decryption was incorrect."));
            } else {
                QDialog::accept(); // Success
            }
            break;
        case ChangePass:
            if (newpass1 == newpass2) {
                if (model->changePassphrase(oldpass, newpass1)) {
                    QMessageBox::information(
                        this, tr("Wallet encrypted"),
                        tr("Wallet passphrase was successfully changed."));
                    QDialog::accept(); // Success
                } else {
                    QMessageBox::critical(
                        this, tr("Wallet encryption failed"),
                        tr("The passphrase entered for the wallet decryption "
                           "was incorrect."));
                }
            } else {
                QMessageBox::critical(
                    this, tr("Wallet encryption failed"),
                    tr("The supplied passphrases do not match."));
            }
            break;
    }
}

void AskPassphraseDialog::textChanged() {
    // Validate input, set Ok button to enabled when acceptable
    bool acceptable = false;
    switch (mode) {
        case Encrypt: // New passphrase x2
            acceptable = !ui->passEdit2->text().isEmpty() &&
                         !ui->passEdit3->text().isEmpty();
            break;
        case Unlock: // Old passphrase x1
        case Decrypt:
            acceptable = !ui->passEdit1->text().isEmpty();
            break;
        case ChangePass: // Old passphrase x1, new passphrase x2
            acceptable = !ui->passEdit1->text().isEmpty() &&
                         !ui->passEdit2->text().isEmpty() &&
                         !ui->passEdit3->text().isEmpty();
            break;
    }
    ui->buttonBox->button(QDialogButtonBox::Ok)->setEnabled(acceptable);
}

bool AskPassphraseDialog::event(QEvent *event) {
    // Detect Caps Lock key press.
    if (event->type() == QEvent::KeyPress) {
        QKeyEvent *ke = static_cast<QKeyEvent *>(event);
        if (ke->key() == Qt::Key_CapsLock) {
            fCapsLock = !fCapsLock;
        }
        if (fCapsLock) {
            ui->capsLabel->setText(tr("Warning: The Caps Lock key is on!"));
        } else {
            ui->capsLabel->clear();
        }
    }
    return QWidget::event(event);
}

void AskPassphraseDialog::toggleShowPassword(bool show) {
    ui->toggleShowPasswordButton->setDown(show);
    const auto renderingMode = show ? QLineEdit::Normal : QLineEdit::Password;
    ui->passEdit1->setEchoMode(renderingMode);
    ui->passEdit2->setEchoMode(renderingMode);
    ui->passEdit3->setEchoMode(renderingMode);
}

bool AskPassphraseDialog::eventFilter(QObject *object, QEvent *event) {
    /* Detect Caps Lock.
     * There is no good OS-independent way to check a key state in Qt, but
     * we can detect Caps Lock by checking for the following condition:
     * Shift key is down and the result is a lower case character, or
     * Shift key is not down and the result is an upper case character.
     */
    if (event->type() == QEvent::KeyPress) {
        QKeyEvent *ke = static_cast<QKeyEvent *>(event);
        QString str = ke->text();
        if (str.length() != 0) {
            const QChar *psz = str.unicode();
            bool fShift = (ke->modifiers() & Qt::ShiftModifier) != 0;
            if ((fShift && *psz >= 'a' && *psz <= 'z') ||
                (!fShift && *psz >= 'A' && *psz <= 'Z')) {
                fCapsLock = true;
                ui->capsLabel->setText(tr("Warning: The Caps Lock key is on!"));
            } else if (psz->isLetter()) {
                fCapsLock = false;
                ui->capsLabel->clear();
            }
        }
    }
    return QDialog::eventFilter(object, event);
}

static void SecureClearQLineEdit(QLineEdit *edit) {
    // Attempt to overwrite text so that they do not linger around in memory
    edit->setText(QString(" ").repeated(edit->text().size()));
    edit->clear();
}

void AskPassphraseDialog::secureClearPassFields() {
    SecureClearQLineEdit(ui->passEdit1);
    SecureClearQLineEdit(ui->passEdit2);
    SecureClearQLineEdit(ui->passEdit3);
}