Reduce input capability fingerprinting through normalization: reduce the amount of hardware-specific information exposed through pointer and touch capability APIs.

Normalize pointer type, hover capability, and maximum touch points to common profiles instead of exposing the exact input hardware configuration. This avoids exposing differences between devices with similar usage patterns, such as desktop systems with optional touchscreen hardware.
2026-07-10 13:39:41 +02:00
parent 7a53b69f4b
commit 7bfd4e7e07
2 changed files with 116 additions and 0 deletions
@@ -308,6 +308,7 @@ Disable-minikin-hyphenation.patch
 Disable-integration-with-Gemini.patch
 Disable-AppRating.patch
 Enable-Android-DevTools-Frontend.patch
+Reduce-input-capability-fingerprinting-through-normalization.patch

 # temporary or wip patches
 Temp-disable-predictive-back-gesture.patch
@@ -0,0 +1,115 @@
+From: uazo <uazo@users.noreply.github.com>
+Date: Fri, 10 Jul 2026 06:28:01 +0000
+Subject: Reduce input capability fingerprinting through normalization
+
+Reduce the amount of hardware-specific information exposed through pointer and
+touch capability APIs.
+Normalize pointer type, hover capability, and maximum touch points to common
+profiles instead of exposing the exact input hardware configuration.
+This avoids exposing differences between devices with similar usage patterns,
+such as desktop systems with optional touchscreen hardware.
+
+License: GPL-2.0-or-later - https://spdx.org/licenses/GPL-2.0-or-later.html
+---
+ .../java/src/org/chromium/ui/base/TouchDevice.java     | 10 +++++-----
+ ui/base/pointer/pointer_device_linux.cc                |  4 ++++
+ ui/base/pointer/pointer_device_win.cc                  |  3 +++
+ 3 files changed, 12 insertions(+), 5 deletions(-)
+
+diff --git a/ui/android/java/src/org/chromium/ui/base/TouchDevice.java b/ui/android/java/src/org/chromium/ui/base/TouchDevice.java
+--- a/ui/android/java/src/org/chromium/ui/base/TouchDevice.java
+++ b/ui/android/java/src/org/chromium/ui/base/TouchDevice.java
+@@ -37,18 +37,17 @@ public class TouchDevice {
+         } else if (ContextUtils.getApplicationContext()
+                 .getPackageManager()
+                 .hasSystemFeature(PackageManager.FEATURE_TOUCHSCREEN_MULTITOUCH_DISTINCT)) {
+-            return 2;
+            return 5;
+         } else if (ContextUtils.getApplicationContext()
+                 .getPackageManager()
+                 .hasSystemFeature(PackageManager.FEATURE_TOUCHSCREEN_MULTITOUCH)) {
+-            return 2;
+            return 5;
+         } else if (ContextUtils.getApplicationContext()
+                 .getPackageManager()
+                 .hasSystemFeature(PackageManager.FEATURE_TOUCHSCREEN)) {
+-            return 1;
+-        } else {
+-            return 0;
+            return 5;
+         }
+        return 0;
+     }
+ 
+     /**
+@@ -58,6 +57,7 @@ public class TouchDevice {
+      */
+     @CalledByNative
+     private static int[] availablePointerAndHoverTypes() {
+        if ((true)) return new int[] {PointerType.COARSE, HoverType.NONE};
+         int pointerTypes = 0;
+         int hoverTypes = 0;
+ 
+diff --git a/ui/base/pointer/pointer_device_linux.cc b/ui/base/pointer/pointer_device_linux.cc
+--- a/ui/base/pointer/pointer_device_linux.cc
+++ b/ui/base/pointer/pointer_device_linux.cc
+@@ -15,6 +15,7 @@ namespace ui {
+ namespace {
+ 
+ bool IsTouchDevicePresent() {
+  if ((true)) return false;
+   return !DeviceDataManager::GetInstance()->GetTouchscreenDevices().empty();
+ }
+ 
+@@ -31,6 +32,7 @@ bool IsMouseOrTouchpadPresent() {
+ }  // namespace
+ 
+ std::pair<int, int> GetAvailablePointerAndHoverTypesImpl() {
+  if ((true)) return {POINTER_TYPE_FINE, HOVER_TYPE_HOVER};
+   int pointer_types = IsTouchDevicePresent() ? POINTER_TYPE_COARSE : 0;
+   int hover_types = HOVER_TYPE_NONE;
+   if (IsMouseOrTouchpadPresent()) {
+@@ -41,6 +43,7 @@ std::pair<int, int> GetAvailablePointerAndHoverTypesImpl() {
+ }
+ 
+ TouchScreensAvailability GetTouchScreensAvailability() {
+  if ((true)) return TouchScreensAvailability::NONE;
+   if (!IsTouchDevicePresent()) {
+     return TouchScreensAvailability::NONE;
+   }
+@@ -51,6 +54,7 @@ TouchScreensAvailability GetTouchScreensAvailability() {
+ }
+ 
+ int MaxTouchPoints() {
+  if ((true)) return 0;
+   const std::vector<TouchscreenDevice>& touchscreen_devices =
+       DeviceDataManager::GetInstance()->GetTouchscreenDevices();
+   const auto& it = std::ranges::max_element(touchscreen_devices, {},
+diff --git a/ui/base/pointer/pointer_device_win.cc b/ui/base/pointer/pointer_device_win.cc
+--- a/ui/base/pointer/pointer_device_win.cc
+++ b/ui/base/pointer/pointer_device_win.cc
+@@ -18,6 +18,7 @@ namespace ui {
+ namespace {
+ 
+ bool IsTouchDevicePresent() {
+  if ((true)) return false;
+   const int value = GetSystemMetrics(SM_DIGITIZER);
+   return (value & NID_READY) &&
+          ((value & NID_INTEGRATED_TOUCH) || (value & NID_EXTERNAL_TOUCH));
+@@ -48,6 +49,7 @@ PointerDevice ToPointerDevice(const POINTER_DEVICE_INFO& device) {
+ }  // namespace
+ 
+ std::pair<int, int> GetAvailablePointerAndHoverTypesImpl() {
+  if ((true)) return {POINTER_TYPE_FINE, HOVER_TYPE_HOVER};
+   // `IsDeviceUsedAsATablet()` guarantees that the device has a touch screen and
+   // has no keyboard connected. On Windows 10 it means that it has verified with
+   // `GetSystemMetrics(SM_CONVERTIBLESLATEMODE)`.
+@@ -73,6 +75,7 @@ TouchScreensAvailability GetTouchScreensAvailability() {
+ }
+ 
+ int MaxTouchPoints() {
+  if ((true)) return 0;
+   return IsTouchDevicePresent() ? GetSystemMetrics(SM_MAXIMUMTOUCHES) : 0;
+ }
+ 
+--