tor-browser

commit cab2fcca42615a29c1504c065b7721d337b5d67b
parent b1323404cafad60b36eb1cf20a2b90de579c7f74
Author: Henry Wilkes <henry@torproject.org>
Date:   Tue, 12 Dec 2023 11:50:52 +0000

BB 42528: Don't leak system scrollbar size on windows.

Diffstat:
M
widget/ScrollbarDrawingWin.cpp
 | 
6
+++++-
M
widget/ScrollbarDrawingWin11.cpp
 | 
6
++++++

2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/widget/ScrollbarDrawingWin.cpp b/widget/ScrollbarDrawingWin.cpp
@@ -11,6 +11,7 @@
 #include "nsLayoutUtils.h"
 #include "Theme.h"
 #include "nsNativeTheme.h"
+#include "nsContentUtils.h"
 
 namespace mozilla::widget {
 
@@ -157,7 +158,10 @@ void ScrollbarDrawingWin::RecomputeScrollbarParams() {
   }
   ConfigureScrollbarSize(defaultSize);
 
-  if (StaticPrefs::widget_non_native_theme_win_scrollbar_use_system_size()) {
+  // Do not leak system size when using ResistFingerprinting.
+  if (!nsContentUtils::ShouldResistFingerprinting("No context available",
+                                                  RFPTarget::CSSResolution) &&
+      StaticPrefs::widget_non_native_theme_win_scrollbar_use_system_size()) {
     ConfigureScrollbarSize(LookAndFeel::GetInt(
         LookAndFeel::IntID::SystemScrollbarSize, defaultSize));
   }
diff --git a/widget/ScrollbarDrawingWin11.cpp b/widget/ScrollbarDrawingWin11.cpp
@@ -11,6 +11,7 @@
 #include "nsLayoutUtils.h"
 #include "Theme.h"
 #include "nsNativeTheme.h"
+#include "nsContentUtils.h"
 
 using mozilla::gfx::sRGBColor;
 
@@ -348,6 +349,11 @@ bool ScrollbarDrawingWin11::PaintScrollbarThumb(
 
 void ScrollbarDrawingWin11::RecomputeScrollbarParams() {
   ScrollbarDrawingWin::RecomputeScrollbarParams();
+  if (nsContentUtils::ShouldResistFingerprinting("No context available",
+                                                 RFPTarget::CSSResolution)) {
+    // Do not distinguish sizes between windows 10 and 11.
+    return;
+  }
   // TODO(emilio): Maybe make this configurable? Though this doesn't respect
   // classic Windows registry settings, and cocoa overlay scrollbars also don't
   // respect the override it seems, so this should be fine.