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QVariant: Avoid crash when constructed from unsuitable metatype

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If the metatype does not support copy and default construction, then it
it unsuitunsuitable for use in QMetaType. We cannot prevent users from
passing in such metatypes (as we have e.g. a ctor taking QMetaType), so
verify this in customConstruct, and make the variant invalid in that
case.

Change-Id: Ib1f0149c8fb9a1cce0049fd0311980754cc85d1b
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
(cherry picked from commit 6a0e59ed506ecb7d6a1bc17beedd938d36a1d26f)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Fabian Kosmale 2022-07-18 09:17:35 +02:00 committed by Qt Cherry-pick Bot
parent d726a463e7
commit 8826fb80f0
2 changed files with 57 additions and 3 deletions
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13
src/corelib/kernel/qvariant.cpp
View File

@ -220,11 +220,15 @@ static void customConstruct(QVariant::Private *d, const void *copy)
*d = QVariant::Private();
return;
}
if (!(iface->copyCtr && iface->defaultCtr)) {
// QVariant requires type to be copy and default constructible
*d = QVariant::Private();
qWarning("QVariant: Provided metatype does not support "
"destruction, copy and default construction");
return;
}
if (QVariant::Private::canUseInternalSpace(iface)) {
// QVariant requires type to be copy and default constructible
Q_ASSERT(iface->copyCtr);
Q_ASSERT(iface->defaultCtr);
if (copy)
iface->copyCtr(iface, &d->data, copy);
else
@ -781,6 +785,9 @@ QVariant::QVariant(const QVariant &p)
instead to construct variants from the pointer types represented by
\c QMetaType::VoidStar, and \c QMetaType::QObjectStar.
If \a type does not support copy and default construction, the variant will
be invalid.
\sa QVariant::fromValue(), QMetaType::Type
*/
QVariant::QVariant(QMetaType type, const void *copy) : d(type)

47
tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp
View File

@ -287,6 +287,9 @@ private slots:
void moveOperations();
void equalsWithoutMetaObject();
void constructFromIncompatibleMetaType_data();
void constructFromIncompatibleMetaType();
private:
void dataStream_data(QDataStream::Version version);
void loadQVariantFromDataStream(QDataStream::Version version);
@ -5107,5 +5110,49 @@ void tst_QVariant::equalsWithoutMetaObject()
QVERIFY(qobjectVariant != noMetaObjectVariant);
}
class NonDefaultConstructible
{
NonDefaultConstructible(int ) {}
};
struct Indestructible
{
Indestructible() {}
Indestructible(const Indestructible &) {}
Indestructible &operator=(const Indestructible &) { return *this; }
private:
~Indestructible() {}
};
void tst_QVariant::constructFromIncompatibleMetaType_data()
{
QTest::addColumn<QMetaType>("type");
auto addRow = [](QMetaType meta) {
QTest::newRow(meta.name()) << meta;
};
addRow(QMetaType::fromType<void>());
addRow(QMetaType::fromType<NonDefaultConstructible>());
addRow(QMetaType::fromType<QObject>());
addRow(QMetaType::fromType<Indestructible>());
}
void tst_QVariant::constructFromIncompatibleMetaType()
{
QFETCH(QMetaType, type);
// in that case, we run into a different condition (size == 0), and do not warn
if (QTest::currentDataTag() != QLatin1String("void"))
QTest::ignoreMessage(
QtWarningMsg,
"QVariant: Provided metatype does not support destruction, copy and default construction");
QVariant var(type, nullptr);
QVERIFY(!var.isValid());
QVERIFY(!var.metaType().isValid());
QVariant regular(1.0);
QVERIFY(!var.canView(type));
QVERIFY(!var.canConvert(type));
QVERIFY(!QVariant(regular).convert(type));
}
QTEST_MAIN(tst_QVariant)
#include "tst_qvariant.moc"