forked from mirrors/gecko-dev
07cbc511d5
This patch introduces random noises to data extraction functions of canvas element and offscreen canvas. The random noise is based on the random key of the cookieJarSettings and the image data itself. The random noises would interfere the ability of fingerprinters that use canvas data to fingerprint users. The random noise will make unique canvas finerprint to for every browsing session. Therefore, fingerprinter cannot use canvas fingerprint to tracker individuals across browsing sessions. Differential Revision: https://phabricator.services.mozilla.com/D175499
118 lines
3.8 KiB
C++
118 lines
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#include "nsICanvasRenderingContextInternal.h"
|
|
|
|
#include "mozilla/dom/CanvasUtils.h"
|
|
#include "mozilla/dom/Document.h"
|
|
#include "mozilla/dom/WorkerCommon.h"
|
|
#include "mozilla/dom/WorkerPrivate.h"
|
|
#include "mozilla/PresShell.h"
|
|
#include "nsPIDOMWindow.h"
|
|
#include "nsRefreshDriver.h"
|
|
|
|
nsICanvasRenderingContextInternal::nsICanvasRenderingContextInternal() =
|
|
default;
|
|
|
|
nsICanvasRenderingContextInternal::~nsICanvasRenderingContextInternal() =
|
|
default;
|
|
|
|
mozilla::PresShell* nsICanvasRenderingContextInternal::GetPresShell() {
|
|
if (mCanvasElement) {
|
|
return mCanvasElement->OwnerDoc()->GetPresShell();
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
nsIGlobalObject* nsICanvasRenderingContextInternal::GetParentObject() const {
|
|
if (mCanvasElement) {
|
|
return mCanvasElement->OwnerDoc()->GetScopeObject();
|
|
}
|
|
if (mOffscreenCanvas) {
|
|
return mOffscreenCanvas->GetParentObject();
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
nsIPrincipal* nsICanvasRenderingContextInternal::PrincipalOrNull() const {
|
|
if (mCanvasElement) {
|
|
return mCanvasElement->NodePrincipal();
|
|
}
|
|
if (mOffscreenCanvas) {
|
|
nsIGlobalObject* global = mOffscreenCanvas->GetParentObject();
|
|
if (global) {
|
|
return global->PrincipalOrNull();
|
|
}
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
nsICookieJarSettings* nsICanvasRenderingContextInternal::GetCookieJarSettings()
|
|
const {
|
|
if (mCanvasElement) {
|
|
return mCanvasElement->OwnerDoc()->CookieJarSettings();
|
|
}
|
|
|
|
// If there is an offscreen canvas, attempt to retrieve its owner window
|
|
// and return the cookieJarSettings for the window's document, if available.
|
|
if (mOffscreenCanvas) {
|
|
nsCOMPtr<nsPIDOMWindowInner> win =
|
|
do_QueryInterface(mOffscreenCanvas->GetOwnerGlobal());
|
|
|
|
if (win) {
|
|
return win->GetExtantDoc()->CookieJarSettings();
|
|
}
|
|
|
|
// If the owner window cannot be retrieved, check if there is a current
|
|
// worker and return its cookie jar settings if available.
|
|
mozilla::dom::WorkerPrivate* worker =
|
|
mozilla::dom::GetCurrentThreadWorkerPrivate();
|
|
|
|
if (worker) {
|
|
return worker->CookieJarSettings();
|
|
}
|
|
}
|
|
|
|
return nullptr;
|
|
}
|
|
|
|
void nsICanvasRenderingContextInternal::RemovePostRefreshObserver() {
|
|
if (mRefreshDriver) {
|
|
mRefreshDriver->RemovePostRefreshObserver(this);
|
|
mRefreshDriver = nullptr;
|
|
}
|
|
}
|
|
|
|
void nsICanvasRenderingContextInternal::AddPostRefreshObserverIfNecessary() {
|
|
if (!GetPresShell() || !GetPresShell()->GetPresContext() ||
|
|
!GetPresShell()->GetPresContext()->RefreshDriver()) {
|
|
return;
|
|
}
|
|
mRefreshDriver = GetPresShell()->GetPresContext()->RefreshDriver();
|
|
mRefreshDriver->AddPostRefreshObserver(this);
|
|
}
|
|
|
|
void nsICanvasRenderingContextInternal::DoSecurityCheck(
|
|
nsIPrincipal* aPrincipal, bool aForceWriteOnly, bool aCORSUsed) {
|
|
if (mCanvasElement) {
|
|
mozilla::CanvasUtils::DoDrawImageSecurityCheck(mCanvasElement, aPrincipal,
|
|
aForceWriteOnly, aCORSUsed);
|
|
} else if (mOffscreenCanvas) {
|
|
mozilla::CanvasUtils::DoDrawImageSecurityCheck(mOffscreenCanvas, aPrincipal,
|
|
aForceWriteOnly, aCORSUsed);
|
|
}
|
|
}
|
|
|
|
bool nsICanvasRenderingContextInternal::ShouldResistFingerprinting(
|
|
mozilla::RFPTarget aTarget) const {
|
|
if (mCanvasElement) {
|
|
return mCanvasElement->OwnerDoc()->ShouldResistFingerprinting(aTarget);
|
|
}
|
|
if (mOffscreenCanvas) {
|
|
return mOffscreenCanvas->ShouldResistFingerprinting(aTarget);
|
|
}
|
|
// Last resort, just check the global preference
|
|
return nsContentUtils::ShouldResistFingerprinting("Fallback", aTarget);
|
|
}
|