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author | Marc Mutz <marc.mutz@kdab.com> | 2016-03-07 20:26:14 +0100 |
---|---|---|
committer | Marc Mutz <marc.mutz@kdab.com> | 2016-03-09 07:42:50 +0000 |
commit | 1b441c3941efc56f9b0ead35a4501056a74a77e1 (patch) | |
tree | ba4ec7f678c9f91deaa1b3ba8a50aec07957ac45 /src/widgets | |
parent | fb7ef2b9f5cbc375fb35690326501be6a117314d (diff) |
Q*Application: fix UB caused by accessing QGuiApplication from QCoreApplication ctor
As reported by ubsan:
src/gui/kernel/qplatformintegration.cpp:463:10: runtime error: downcast of address 0x7ffdc2942490 which does not point to an object of type 'QGuiApplication'
0x7ffdc2942490: note: object is of type 'QCoreApplication'
src/gui/kernel/qplatformintegration.cpp:466:14: runtime error: downcast of address 0x7ffdc2942490 which does not point to an object of type 'QGuiApplication'
0x7ffdc2942490: note: object is of type 'QCoreApplication'
src/gui/kernel/qplatformintegration.cpp:466:43: runtime error: member call on address 0x7ffdc2942490 which does not point to an object of type 'QGuiApplication'
0x7ffdc2942490: note: object is of type 'QCoreApplication'
to name just a few which are reported when running gui and widget
auto-tests; there're definitely more where these came from.
This is caused by QCoreApplication::init() being called from the
QCoreApplication ctor, calling virtual functions on Q*AppPrivate,
which happen to attempt, in this case, to emit QGuiApp signals.
At that point in time, the QGuiApplication ctor has not entered
the constructor body, ergo the object is still a QCoreApplication,
and calling the signal, as a member function on the derived class,
invokes UB.
Fix by cleaning up the wild mix of initialization functions used in
this hierarchy. The cleanup restores the
1. Q*ApplicationPrivate::Q*ApplicationPrivate()
2. Q*ApplicationPrivate::init(), calling each base class'
init() as the first thing
two-stage construction pattern commonly used elsewhere in Qt to make
sure that the public class' object is fully constructed by the time
each level's Private::init() is called.
Change-Id: I290402b3232315d7ed687c97e740bfbdbd3ecd1a
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
Diffstat (limited to 'src/widgets')
-rw-r--r-- | src/widgets/kernel/qapplication.cpp | 9 | ||||
-rw-r--r-- | src/widgets/kernel/qapplication_p.h | 2 |
2 files changed, 8 insertions, 3 deletions
diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp index f7d4139ed8..b7de0d7a7e 100644 --- a/src/widgets/kernel/qapplication.cpp +++ b/src/widgets/kernel/qapplication.cpp @@ -562,13 +562,18 @@ QApplication::QApplication(int &argc, char **argv) QApplication::QApplication(int &argc, char **argv, int _internal) #endif : QGuiApplication(*new QApplicationPrivate(argc, argv, _internal)) -{ Q_D(QApplication); d->construct(); } +{ + Q_D(QApplication); + d->init(); +} /*! \internal */ -void QApplicationPrivate::construct() +void QApplicationPrivate::init() { + QGuiApplicationPrivate::init(); + initResources(); qt_is_gui_used = (application_type != QApplicationPrivate::Tty); diff --git a/src/widgets/kernel/qapplication_p.h b/src/widgets/kernel/qapplication_p.h index cb158011f0..832d37a329 100644 --- a/src/widgets/kernel/qapplication_p.h +++ b/src/widgets/kernel/qapplication_p.h @@ -150,7 +150,7 @@ public: bool notify_helper(QObject *receiver, QEvent * e); - void construct( + void init( #ifdef Q_DEAD_CODE_FROM_QT4_X11 Display *dpy = 0, Qt::HANDLE visual = 0, Qt::HANDLE cmap = 0 #endif |