PawletOS/cromite
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
master
cromite/build/patches/High-Resolution-Timing-Mitigation.patch
T

147 lines
6.5 KiB
Diff
Raw Permalink Blame History

From: uazo <uazo@users.noreply.github.com>
Date: Tue, 1 Jul 2025 14:49:55 +0000
Subject: High Resolution Timing Mitigation
Decreases high timer resolution in Blink.
License: GPL-2.0-or-later - https://spdx.org/licenses/GPL-2.0-or-later.html
---
.../High-resolution-timing-mitigation.inc | 8 ++++++++
.../High-resolution-timing-mitigation.inc | 3 +++
.../High-resolution-timing-mitigation.inc | 1 +
.../renderer/core/timing/time_clamper.cc | 19 +++++++++++++++----
.../blink/renderer/core/timing/time_clamper.h | 5 +++--
.../video_frame_callback_requester_impl.cc | 17 +++++++----------
6 files changed, 37 insertions(+), 16 deletions(-)
create mode 100644 cromite_flags/chrome/browser/about_flags_cc/High-resolution-timing-mitigation.inc
create mode 100644 cromite_flags/third_party/blink/common/features_cc/High-resolution-timing-mitigation.inc
create mode 100644 cromite_flags/third_party/blink/common/features_h/High-resolution-timing-mitigation.inc
diff --git a/cromite_flags/chrome/browser/about_flags_cc/High-resolution-timing-mitigation.inc b/cromite_flags/chrome/browser/about_flags_cc/High-resolution-timing-mitigation.inc
new file mode 100644
--- /dev/null
+++ b/cromite_flags/chrome/browser/about_flags_cc/High-resolution-timing-mitigation.inc
@@ -0,0 +1,8 @@
+#ifdef FLAG_SECTION
+
+ {"high-resolution-timing-mitigation",
+ "High Resolution Timing Mitigation",
+ "Decreases timer resolution in Blink.", kOsAll,
+ FEATURE_VALUE_TYPE(blink::features::kHighResolutionTimingMitigation)},
+
+#endif
diff --git a/cromite_flags/third_party/blink/common/features_cc/High-resolution-timing-mitigation.inc b/cromite_flags/third_party/blink/common/features_cc/High-resolution-timing-mitigation.inc
new file mode 100644
--- /dev/null
+++ b/cromite_flags/third_party/blink/common/features_cc/High-resolution-timing-mitigation.inc
@@ -0,0 +1,3 @@
+CROMITE_FEATURE(kHighResolutionTimingMitigation,
+ "HighResolutionTimingMitigation",
+ base::FEATURE_ENABLED_BY_DEFAULT);
diff --git a/cromite_flags/third_party/blink/common/features_h/High-resolution-timing-mitigation.inc b/cromite_flags/third_party/blink/common/features_h/High-resolution-timing-mitigation.inc
new file mode 100644
--- /dev/null
+++ b/cromite_flags/third_party/blink/common/features_h/High-resolution-timing-mitigation.inc
@@ -0,0 +1 @@
+BLINK_COMMON_EXPORT BASE_DECLARE_FEATURE(kHighResolutionTimingMitigation);
diff --git a/third_party/blink/renderer/core/timing/time_clamper.cc b/third_party/blink/renderer/core/timing/time_clamper.cc
--- a/third_party/blink/renderer/core/timing/time_clamper.cc
+++ b/third_party/blink/renderer/core/timing/time_clamper.cc
@@ -7,6 +7,9 @@
#include "base/bit_cast.h"
#include "base/rand_util.h"
+#include "third_party/blink/public/common/features.h"
+#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
+
#include <cmath>
namespace blink {
@@ -15,7 +18,10 @@ namespace {
const int64_t kTenLowerDigitsMod = 10000000000;
} // namespace
-TimeClamper::TimeClamper() : secret_(base::RandUint64()) {}
+TimeClamper::TimeClamper() : secret_(base::RandUint64()) {
+ timing_mitigation_ =
+ base::FeatureList::IsEnabled(features::kHighResolutionTimingMitigation);
+}
// This is using int64 for timestamps, because https://bit.ly/doubles-are-bad
base::TimeDelta TimeClamper::ClampTimeResolution(
@@ -40,9 +46,14 @@ base::TimeDelta TimeClamper::ClampTimeResolution(
// Determine resolution based on the context's cross-origin isolation
// capability. https://w3c.github.io/hr-time/#dfn-coarsen-time
- int resolution = cross_origin_isolated_capability
- ? kFineResolutionMicroseconds
- : kCoarseResolutionMicroseconds;
+ int resolution;
+ if (timing_mitigation_) {
+ resolution = 1000;
+ } else {
+ resolution = cross_origin_isolated_capability
+ ? 5 /*kFineResolutionMicroseconds*/
+ : 100 /*kCoarseResolutionMicroseconds*/;
+ }
// Clamped the time based on the resolution.
int64_t clamped_time = time_lower_digits - time_lower_digits % resolution;
diff --git a/third_party/blink/renderer/core/timing/time_clamper.h b/third_party/blink/renderer/core/timing/time_clamper.h
--- a/third_party/blink/renderer/core/timing/time_clamper.h
+++ b/third_party/blink/renderer/core/timing/time_clamper.h
@@ -20,8 +20,8 @@ class CORE_EXPORT TimeClamper {
DISALLOW_NEW();
public:
- static constexpr int kCoarseResolutionMicroseconds = 100;
- static constexpr int kFineResolutionMicroseconds = 5;
+ // static constexpr int kCoarseResolutionMicroseconds = 100;
+ // static constexpr int kFineResolutionMicroseconds = 5;
TimeClamper();
TimeClamper(const TimeClamper&) = delete;
@@ -45,6 +45,7 @@ class CORE_EXPORT TimeClamper {
static inline uint64_t MurmurHash3(uint64_t value);
const uint64_t secret_;
+ bool timing_mitigation_;
};
// Ensure that static TimeClamper instances are trivially destructible,
diff --git a/third_party/blink/renderer/modules/video_rvfc/video_frame_callback_requester_impl.cc b/third_party/blink/renderer/modules/video_rvfc/video_frame_callback_requester_impl.cc
--- a/third_party/blink/renderer/modules/video_rvfc/video_frame_callback_requester_impl.cc
+++ b/third_party/blink/renderer/modules/video_rvfc/video_frame_callback_requester_impl.cc
@@ -22,6 +22,9 @@
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/wtf/functional.h"
+#include "third_party/blink/public/common/features.h"
+#include "third_party/blink/renderer/platform/runtime_enabled_features.h"
+
namespace blink {
namespace {
@@ -316,16 +319,10 @@ double VideoFrameCallbackRequesterImpl::GetClampedTimeInMillis(
// static
double VideoFrameCallbackRequesterImpl::GetCoarseClampedTimeInSeconds(
base::TimeDelta time) {
- constexpr auto kCoarseResolution = base::Microseconds(100);
- // Add this assert, in case TimeClamper's resolution were to change to be
- // stricter.
- static_assert(
- kCoarseResolution >=
- base::Microseconds(TimeClamper::kCoarseResolutionMicroseconds),
- "kCoarseResolution should be at least as coarse as other clock "
- "resolutions");
-
- return time.FloorToMultiple(kCoarseResolution).InSecondsF();
+ if (base::FeatureList::IsEnabled(features::kHighResolutionTimingMitigation))
+ return time.FloorToMultiple(base::Microseconds(1000)).InSecondsF();
+ else
+ return time.FloorToMultiple(base::Microseconds(100)).InSecondsF();
}
int VideoFrameCallbackRequesterImpl::requestVideoFrameCallback(
--
Reference in New Issue View Git Blame Copy Permalink