tor-browser

commit adc5a7fa4ebb6efe9789ecbf0d057cf663b71174
parent da8dbdb93bf7e257ba0b8c6e24dbefba75173eaa
Author: Emilio Cobos Álvarez <emilio@crisal.io>
Date:   Wed, 17 Dec 2025 19:38:35 +0000

Bug 2001722 - Clamp system decoration offset if the WM gives us broken rects. r=stransky

Differential Revision: https://phabricator.services.mozilla.com/D276665

Diffstat:
M
widget/gtk/nsWindow.cpp
 | 
18
++++++++++++++++--

1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/widget/gtk/nsWindow.cpp b/widget/gtk/nsWindow.cpp
@@ -3362,8 +3362,22 @@ void nsWindow::RecomputeBoundsX11(bool aMayChangeCsdMargin) {
   LOGVERBOSE("  toplevelBounds %s", ToString(toplevelBounds).c_str());
 
   // Offset from system decoration to gtk decoration.
-  const auto systemDecorationOffset =
-      toplevelBounds.TopLeft() - toplevelBoundsWithTitlebar.TopLeft();
+  const auto systemDecorationOffset = [&] {
+    auto offset =
+        toplevelBounds.TopLeft() - toplevelBoundsWithTitlebar.TopLeft();
+    // If the WM sends us broken values, try to clamp to something sensible.
+    // The offset will never be more than the bounds difference, nor negative.
+    // See bug 2001722 for an example where this happened.
+    offset.x =
+        std::max(std::min(int32_t(offset.x), toplevelBoundsWithTitlebar.width -
+                                                 toplevelBounds.width),
+                 0);
+    offset.y =
+        std::max(std::min(int32_t(offset.y), toplevelBoundsWithTitlebar.height -
+                                                 toplevelBounds.height),
+                 0);
+    return offset;
+  }();
 
   // This is relative to our parent window, that is, to topLevelBounds.
   mClientArea = GetBounds(mGdkWindow);