gecko-dev/dom/base/nsScreen.cpp
Arthur Edelstein 54c8149d55 Bug 1281949 - When resisting fingerprinting, spoof screen.orientation
When privacy.resistFingerprinting is enabled, make sure that
screen.orientation.angle -> 0 and
screen.orientation.type -> "landscape-primary"

Also refactors screen.mozOrientation.

Based on https://trac.torproject.org/18958
2016-06-24 09:53:00 -07:00

361 lines
9.9 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "mozilla/dom/Event.h" // for nsIDOMEvent::InternalDOMEvent()
#include "mozilla/dom/ScreenBinding.h"
#include "nsContentUtils.h"
#include "nsScreen.h"
#include "nsIDocument.h"
#include "nsIDocShell.h"
#include "nsIDocument.h"
#include "nsPresContext.h"
#include "nsCOMPtr.h"
#include "nsIDocShellTreeItem.h"
#include "nsLayoutUtils.h"
#include "nsJSUtils.h"
#include "nsDeviceContext.h"
using namespace mozilla;
using namespace mozilla::dom;
/* static */ already_AddRefed<nsScreen>
nsScreen::Create(nsPIDOMWindowInner* aWindow)
{
MOZ_ASSERT(aWindow);
MOZ_ASSERT(aWindow->IsInnerWindow());
if (!aWindow->GetDocShell()) {
return nullptr;
}
nsCOMPtr<nsIScriptGlobalObject> sgo = do_QueryInterface(aWindow);
NS_ENSURE_TRUE(sgo, nullptr);
RefPtr<nsScreen> screen = new nsScreen(aWindow);
return screen.forget();
}
nsScreen::nsScreen(nsPIDOMWindowInner* aWindow)
: DOMEventTargetHelper(aWindow)
, mScreenOrientation(new ScreenOrientation(aWindow, this))
{
}
nsScreen::~nsScreen()
{
}
// QueryInterface implementation for nsScreen
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(nsScreen)
NS_INTERFACE_MAP_ENTRY(nsIDOMScreen)
NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
NS_IMPL_ADDREF_INHERITED(nsScreen, DOMEventTargetHelper)
NS_IMPL_RELEASE_INHERITED(nsScreen, DOMEventTargetHelper)
NS_IMPL_CYCLE_COLLECTION_INHERITED(nsScreen,
DOMEventTargetHelper,
mScreenOrientation)
int32_t
nsScreen::GetPixelDepth(ErrorResult& aRv)
{
// Return 24 to prevent fingerprinting.
if (ShouldResistFingerprinting()) {
return 24;
}
nsDeviceContext* context = GetDeviceContext();
if (!context) {
aRv.Throw(NS_ERROR_FAILURE);
return -1;
}
uint32_t depth;
context->GetDepth(depth);
return depth;
}
#define FORWARD_LONG_GETTER(_name) \
NS_IMETHODIMP \
nsScreen::Get ## _name(int32_t* aOut) \
{ \
ErrorResult rv; \
*aOut = Get ## _name(rv); \
return rv.StealNSResult(); \
}
FORWARD_LONG_GETTER(AvailWidth)
FORWARD_LONG_GETTER(AvailHeight)
FORWARD_LONG_GETTER(Width)
FORWARD_LONG_GETTER(Height)
FORWARD_LONG_GETTER(Top)
FORWARD_LONG_GETTER(Left)
FORWARD_LONG_GETTER(AvailTop)
FORWARD_LONG_GETTER(AvailLeft)
FORWARD_LONG_GETTER(PixelDepth)
FORWARD_LONG_GETTER(ColorDepth)
nsPIDOMWindowOuter*
nsScreen::GetOuter() const
{
if (nsPIDOMWindowInner* inner = GetOwner()) {
return inner->GetOuterWindow();
}
return nullptr;
}
nsDeviceContext*
nsScreen::GetDeviceContext()
{
return nsLayoutUtils::GetDeviceContextForScreenInfo(GetOuter());
}
nsresult
nsScreen::GetRect(nsRect& aRect)
{
// Return window inner rect to prevent fingerprinting.
if (ShouldResistFingerprinting()) {
return GetWindowInnerRect(aRect);
}
nsDeviceContext *context = GetDeviceContext();
if (!context) {
return NS_ERROR_FAILURE;
}
context->GetRect(aRect);
LayoutDevicePoint screenTopLeftDev =
LayoutDevicePixel::FromAppUnits(aRect.TopLeft(),
context->AppUnitsPerDevPixel());
DesktopPoint screenTopLeftDesk =
screenTopLeftDev / context->GetDesktopToDeviceScale();
aRect.x = NSToIntRound(screenTopLeftDesk.x);
aRect.y = NSToIntRound(screenTopLeftDesk.y);
aRect.height = nsPresContext::AppUnitsToIntCSSPixels(aRect.height);
aRect.width = nsPresContext::AppUnitsToIntCSSPixels(aRect.width);
return NS_OK;
}
nsresult
nsScreen::GetAvailRect(nsRect& aRect)
{
// Return window inner rect to prevent fingerprinting.
if (ShouldResistFingerprinting()) {
return GetWindowInnerRect(aRect);
}
nsDeviceContext *context = GetDeviceContext();
if (!context) {
return NS_ERROR_FAILURE;
}
nsRect r;
context->GetRect(r);
LayoutDevicePoint screenTopLeftDev =
LayoutDevicePixel::FromAppUnits(r.TopLeft(),
context->AppUnitsPerDevPixel());
DesktopPoint screenTopLeftDesk =
screenTopLeftDev / context->GetDesktopToDeviceScale();
context->GetClientRect(aRect);
aRect.x = NSToIntRound(screenTopLeftDesk.x) +
nsPresContext::AppUnitsToIntCSSPixels(aRect.x - r.x);
aRect.y = NSToIntRound(screenTopLeftDesk.y) +
nsPresContext::AppUnitsToIntCSSPixels(aRect.y - r.y);
aRect.height = nsPresContext::AppUnitsToIntCSSPixels(aRect.height);
aRect.width = nsPresContext::AppUnitsToIntCSSPixels(aRect.width);
return NS_OK;
}
mozilla::dom::ScreenOrientation*
nsScreen::Orientation() const
{
return mScreenOrientation;
}
void
nsScreen::GetMozOrientation(nsString& aOrientation) const
{
switch (mScreenOrientation->DeviceType()) {
case OrientationType::Portrait_primary:
aOrientation.AssignLiteral("portrait-primary");
break;
case OrientationType::Portrait_secondary:
aOrientation.AssignLiteral("portrait-secondary");
break;
case OrientationType::Landscape_primary:
aOrientation.AssignLiteral("landscape-primary");
break;
case OrientationType::Landscape_secondary:
aOrientation.AssignLiteral("landscape-secondary");
break;
default:
MOZ_CRASH("Unacceptable screen orientation type.");
}
}
NS_IMETHODIMP
nsScreen::GetSlowMozOrientation(nsAString& aOrientation)
{
nsString orientation;
GetMozOrientation(orientation);
aOrientation = orientation;
return NS_OK;
}
static void
UpdateDocShellOrientationLock(nsPIDOMWindowInner* aWindow,
ScreenOrientationInternal aOrientation)
{
if (!aWindow) {
return;
}
nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
if (!docShell) {
return;
}
nsCOMPtr<nsIDocShellTreeItem> root;
docShell->GetSameTypeRootTreeItem(getter_AddRefs(root));
nsCOMPtr<nsIDocShell> rootShell(do_QueryInterface(root));
if (!rootShell) {
return;
}
rootShell->SetOrientationLock(aOrientation);
}
bool
nsScreen::MozLockOrientation(const nsAString& aOrientation, ErrorResult& aRv)
{
nsString orientation(aOrientation);
Sequence<nsString> orientations;
if (!orientations.AppendElement(orientation, fallible)) {
aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
return false;
}
return MozLockOrientation(orientations, aRv);
}
bool
nsScreen::MozLockOrientation(const Sequence<nsString>& aOrientations,
ErrorResult& aRv)
{
if (ShouldResistFingerprinting()) {
return false;
}
ScreenOrientationInternal orientation = eScreenOrientation_None;
for (uint32_t i = 0; i < aOrientations.Length(); ++i) {
const nsString& item = aOrientations[i];
if (item.EqualsLiteral("portrait")) {
orientation |= eScreenOrientation_PortraitPrimary |
eScreenOrientation_PortraitSecondary;
} else if (item.EqualsLiteral("portrait-primary")) {
orientation |= eScreenOrientation_PortraitPrimary;
} else if (item.EqualsLiteral("portrait-secondary")) {
orientation |= eScreenOrientation_PortraitSecondary;
} else if (item.EqualsLiteral("landscape")) {
orientation |= eScreenOrientation_LandscapePrimary |
eScreenOrientation_LandscapeSecondary;
} else if (item.EqualsLiteral("landscape-primary")) {
orientation |= eScreenOrientation_LandscapePrimary;
} else if (item.EqualsLiteral("landscape-secondary")) {
orientation |= eScreenOrientation_LandscapeSecondary;
} else if (item.EqualsLiteral("default")) {
orientation |= eScreenOrientation_Default;
} else {
// If we don't recognize the token, we should just return 'false'
// without throwing.
return false;
}
}
switch (mScreenOrientation->GetLockOrientationPermission(false)) {
case ScreenOrientation::LOCK_DENIED:
return false;
case ScreenOrientation::LOCK_ALLOWED:
UpdateDocShellOrientationLock(GetOwner(), orientation);
return mScreenOrientation->LockDeviceOrientation(orientation, false, aRv);
case ScreenOrientation::FULLSCREEN_LOCK_ALLOWED:
UpdateDocShellOrientationLock(GetOwner(), orientation);
return mScreenOrientation->LockDeviceOrientation(orientation, true, aRv);
}
// This is only for compilers that don't understand that the previous switch
// will always return.
MOZ_CRASH("unexpected lock orientation permission value");
}
void
nsScreen::MozUnlockOrientation()
{
if (ShouldResistFingerprinting()) {
return;
}
UpdateDocShellOrientationLock(GetOwner(), eScreenOrientation_None);
mScreenOrientation->UnlockDeviceOrientation();
}
bool
nsScreen::IsDeviceSizePageSize()
{
if (nsPIDOMWindowInner* owner = GetOwner()) {
nsIDocShell* docShell = owner->GetDocShell();
if (docShell) {
return docShell->GetDeviceSizeIsPageSize();
}
}
return false;
}
/* virtual */
JSObject*
nsScreen::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
return ScreenBinding::Wrap(aCx, this, aGivenProto);
}
nsresult
nsScreen::GetWindowInnerRect(nsRect& aRect)
{
aRect.x = 0;
aRect.y = 0;
nsCOMPtr<nsPIDOMWindowInner> win = GetOwner();
if (!win) {
return NS_ERROR_FAILURE;
}
nsresult rv = win->GetInnerWidth(&aRect.width);
NS_ENSURE_SUCCESS(rv, rv);
return win->GetInnerHeight(&aRect.height);
}
bool nsScreen::ShouldResistFingerprinting() const
{
bool resist = false;
nsCOMPtr<nsPIDOMWindowInner> owner = GetOwner();
if (owner) {
resist = nsContentUtils::ShouldResistFingerprinting(owner->GetDocShell());
}
return resist;
}