SubaddressAccount: fix use-after-free bug

src/libwalletqt/SubaddressAccount.cpp

@@ -36,24 +36,34 @@ SubaddressAccount::SubaddressAccount(Monero::SubaddressAccount *subaddressAccoun
     getAll();
 }
 
-QList<Monero::SubaddressAccountRow *> SubaddressAccount::getAll() const
+void SubaddressAccount::getAll() const
 {
     qDebug(__FUNCTION__);
 
     emit refreshStarted();
 
+    {
+        QWriteLocker locker(&m_lock);
         m_rows.clear();
         for (auto &row: m_subaddressAccountImpl->getAll()) {
             m_rows.append(row);
         }
+    }
 
     emit refreshFinished();
-    return m_rows;
 }
 
-Monero::SubaddressAccountRow * SubaddressAccount::getRow(int index) const
+bool SubaddressAccount::getRow(int index, std::function<void (Monero::SubaddressAccountRow &)> callback) const
 {
-    return m_rows.at(index);
+    QReadLocker locker(&m_lock);
+
+    if (index < 0 || index >= m_rows.size())
+    {
+        return false;
+    }
+
+    callback(*m_rows.value(index));
+    return true;
 }
 
 void SubaddressAccount::addRow(const QString &label) const
@@ -76,5 +86,7 @@ void SubaddressAccount::refresh() const
 
 quint64 SubaddressAccount::count() const
 {
+    QReadLocker locker(&m_lock);
+
     return m_rows.size();
 }

src/libwalletqt/SubaddressAccount.h

@@ -31,6 +31,7 @@
 
 #include <wallet/api/wallet2_api.h>
 #include <QObject>
+#include <QReadWriteLock>
 #include <QList>
 #include <QDateTime>
 
@@ -38,8 +39,8 @@ class SubaddressAccount : public QObject
 {
     Q_OBJECT
 public:
-    Q_INVOKABLE QList<Monero::SubaddressAccountRow *> getAll() const;
-    Q_INVOKABLE Monero::SubaddressAccountRow * getRow(int index) const;
+    Q_INVOKABLE void getAll() const;
+    Q_INVOKABLE bool getRow(int index, std::function<void (Monero::SubaddressAccountRow &)> callback) const;
     Q_INVOKABLE void addRow(const QString &label) const;
     Q_INVOKABLE void setLabel(quint32 accountIndex, const QString &label) const;
     Q_INVOKABLE void refresh() const;
@@ -54,6 +55,7 @@ public slots:
 private:
     explicit SubaddressAccount(Monero::SubaddressAccount * subaddressAccountImpl, QObject *parent);
     friend class Wallet;
+    mutable QReadWriteLock m_lock;
     Monero::SubaddressAccount * m_subaddressAccountImpl;
     mutable QList<Monero::SubaddressAccountRow*> m_rows;
 };

src/model/SubaddressAccountModel.cpp

@@ -59,22 +59,28 @@ QVariant SubaddressAccountModel::data(const QModelIndex &index, int role) const
     if (!index.isValid() || index.row() < 0 || (unsigned)index.row() >= m_subaddressAccount->count())
         return {};
 
-    Monero::SubaddressAccountRow * sr = m_subaddressAccount->getRow(index.row());
+    QVariant result;
 
-    QVariant result = "";
+    bool found = m_subaddressAccount->getRow(index.row(), [&result, &role](const Monero::SubaddressAccountRow &row) {
         switch (role) {
         case SubaddressAccountAddressRole:
-        result = QString::fromStdString(sr->getAddress());
+            result = QString::fromStdString(row.getAddress());
             break;
         case SubaddressAccountLabelRole:
-        result = QString::fromStdString(sr->getLabel());
+            result = QString::fromStdString(row.getLabel());
             break;
         case SubaddressAccountBalanceRole:
-        result = QString::fromStdString(sr->getBalance());
+            result = QString::fromStdString(row.getBalance());
             break;
         case SubaddressAccountUnlockedBalanceRole:
-        result = QString::fromStdString(sr->getUnlockedBalance());
+            result = QString::fromStdString(row.getUnlockedBalance());
             break;
+        default:
+            qCritical() << "Unimplemented role" << role;
+        }
+    });
+    if (!found) {
+        qCritical("%s: internal error: invalid index %d", __FUNCTION__, index.row());
     }
 
     return result;