From cc9cefbd5f627ca6f0a6c4f4fc9c4d3c8af21239 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Thu, 18 Apr 2019 23:16:57 +0200
Subject: [PATCH] LibGUI: GWindow's focused widget should be a WeakPtr.

This fixes some very obvious use-after-free accesses.
---
 LibGUI/GWindow.cpp | 2 +-
 LibGUI/GWindow.h   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/LibGUI/GWindow.cpp b/LibGUI/GWindow.cpp
index 31f9c33e8f1..de38f0ffcc4 100644
--- a/LibGUI/GWindow.cpp
+++ b/LibGUI/GWindow.cpp
@@ -337,7 +337,7 @@ void GWindow::set_focused_widget(GWidget* widget)
         GEventLoop::current().post_event(*m_focused_widget, make<GEvent>(GEvent::FocusOut));
         m_focused_widget->update();
     }
-    m_focused_widget = widget;
+    m_focused_widget = widget ? widget->make_weak_ptr() : nullptr;
     if (m_focused_widget) {
         GEventLoop::current().post_event(*m_focused_widget, make<GEvent>(GEvent::FocusIn));
         m_focused_widget->update();
diff --git a/LibGUI/GWindow.h b/LibGUI/GWindow.h
index 9aa9c411127..e276ea6dbb8 100644
--- a/LibGUI/GWindow.h
+++ b/LibGUI/GWindow.h
@@ -120,7 +120,7 @@ private:
     int m_window_id { 0 };
     float m_opacity_when_windowless { 1.0f };
     GWidget* m_main_widget { nullptr };
-    GWidget* m_focused_widget { nullptr };
+    WeakPtr<GWidget> m_focused_widget;
     WeakPtr<GWidget> m_global_cursor_tracking_widget;
     WeakPtr<GWidget> m_automatic_cursor_tracking_widget;
     WeakPtr<GWidget> m_hovered_widget;