security-and-privacy/CanvasBlocker
security-and-privacy/CanvasBlocker
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Hide function replacement

Browse Source 
Fixes #206
This commit is contained in:
kkapsner 2018-07-13 16:58:13 +02:00
parent 9711c67c3f
commit 26529a3653
6 changed files with 375 additions and 281 deletions
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228
lib/intercept.js
View File

@ -158,9 +158,107 @@
});
}
};
let extensionID = browser.extension.getURL("");
scope.intercept = function intercept({subject: window}, {check, checkStack, ask, notify, prefs}){
function getDataURL(object, prefs){
return (
this &&
prefs("storeImageForInspection") &&
prefs("showNotifications")?
(
this instanceof HTMLCanvasElement?
this.toDataURL():
(
this.canvas instanceof HTMLCanvasElement?
this.canvas.toDataURL():
false
)
):
false
);
}
function generateChecker(name, changedFunction, siteStatus, original){
return function checker(callingDepth = 2){
var url = getURL(window);
if (!url){
return undef;
}
var error = new Error();
try {
// return original if the extension itself requested the function
if (
error.stack
.split("\n", callingDepth + 2)[callingDepth + 1]
.split("@", callingDepth + 1)[1]
.startsWith(extensionID)
){
return {allow: true, original, window};
}
}
catch (e) {
// stack had an unknown form
}
if (checkStack(error.stack)){
return {allow: true, original, window};
}
var funcStatus = changedFunction.getStatus(this, siteStatus);
function notifyCallback(messageId){
notify({
url,
errorStack: error.stack,
messageId,
timestamp: new Date(),
functionName: name,
api: changedFunction.api,
dataURL: getDataURL(this, prefs)
});
}
if (funcStatus.active && !prefs("apiWhiteList")[name]){
if (funcStatus.mode === "ask"){
funcStatus.mode = ask({
window: window,
type: changedFunction.type,
api: changedFunction.api,
canvas: this instanceof HTMLCanvasElement?
this:
(
this &&
(this.canvas instanceof HTMLCanvasElement)?
this.canvas:
false
),
errorStack: error.stack
});
}
switch (funcStatus.mode){
case "allow":
return {allow: true, original, window};
case "fake":
setRandomSupplyByType(prefs("rng"));
return {
allow: "fake",
prefs,
notify: notifyCallback,
window,
original
};
//case "block":
default:
return {
allow: false,
notify: notifyCallback
};
}
}
else {
return {allow: true, original, window};
}
};
}
var siteStatus = check({url: getURL(window)});
logging.verbose("status for page", window, siteStatus);
if (siteStatus.mode !== "allow"){
@ -177,117 +275,25 @@
var constructor = getWrapped(window)[object];
if (constructor){
var original = constructor.prototype[name];
Object.defineProperty(
constructor.prototype,
name,
{
enumerable: true,
configureable: true,
get: exportFunction(function(){
var url = getURL(window);
if (!url){
return undef;
}
var error = new Error();
try {
// return original if the extension itself requested the function
if (error.stack.split("\n", 3)[1].split("@", 2)[1].startsWith(extensionID)){
return original;
}
}
catch (e) {
// stack had an unknown form
}
if (checkStack(error.stack)){
return original;
}
var funcStatus = changedFunction.getStatus(this, siteStatus);
function notifyCallback(messageId){
notify({
url,
errorStack: error.stack,
messageId,
timestamp: new Date(),
functionName: name,
api: changedFunction.api,
dataURL:
this &&
prefs("storeImageForInspection") &&
prefs("showNotifications")?
(
this instanceof HTMLCanvasElement?
this.toDataURL():
(
this.canvas instanceof HTMLCanvasElement?
this.canvas.toDataURL():
false
)
):
false
});
}
if (funcStatus.active && !prefs("apiWhiteList")[name]){
if (funcStatus.mode === "ask"){
funcStatus.mode = ask({
window: window,
type: changedFunction.type,
api: changedFunction.api,
canvas: this instanceof HTMLCanvasElement?
this:
(
this &&
(this.canvas instanceof HTMLCanvasElement)?
this.canvas:
false
),
errorStack: error.stack
});
}
switch (funcStatus.mode){
case "allow":
return original;
case "fake":
setRandomSupplyByType(prefs("rng"));
var fake = changedFunction.fakeGenerator(
prefs,
notifyCallback,
window,
original
);
switch (fake){
case true:
return original;
case false:
return undef;
default:
return exportFunction(fake, getWrapped(window));
}
//case "block":
default:
return undef;
}
}
else {
return original;
}
}, window),
set: exportFunction(function(value){
Object.defineProperty(
constructor.prototype,
name,
{
value,
writable: true,
configurable: true,
enumerable: true
}
);
}, window)
const checker = generateChecker(name, changedFunction, siteStatus, original);
var descriptor = Object.getOwnPropertyDescriptor(constructor.prototype, name);
if (descriptor.hasOwnProperty("value")){
if (changedFunction.fakeGenerator){
descriptor.value = exportFunction(
changedFunction.fakeGenerator(checker),
window
);
}
);
else {
descriptor.value = null;
}
}
else {
descriptor.get = exportFunction(function(){
return changedFunction.fakeGenerator(checker);
}, window);
}
Object.defineProperty(constructor.prototype, name, descriptor);
}
});
}

295
lib/modifiedAPI.js
View File

@ -17,6 +17,7 @@
const logging = require("./logging");
const {copyCanvasToWebgl} = require("./webgl");
const getWrapped = require("sdk/getWrapped");
const {hasType, checkerWrapper} = require("./modifiedAPIFunctions");
const modifiedAudioAPI = require("./modifiedAudioAPI");
var randomSupply = null;
@ -151,10 +152,6 @@
}
}
function hasType(status, type){
return status.type.indexOf(type) !== -1;
}
scope.setRandomSupply = function(supply){
randomSupply = supply;
modifiedAudioAPI.setRandomSupply(supply);
@ -186,10 +183,13 @@
}
},
object: "HTMLCanvasElement",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function(context, contextAttributes){
canvasContextType.set(this, context);
return original.apply(this, window.Array.from(arguments));
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
canvasContextType.set(this, context);
return original.apply(this, window.Array.from(args));
});
};
}
},
@ -205,18 +205,21 @@
return status;
},
object: "HTMLCanvasElement",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function toDataURL(){
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify.call(this, "fakedReadout");
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify.call(this, "fakedReadout");
}
return original.apply(fakeCanvas, window.Array.from(args));
}
return original.apply(fakeCanvas, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
@ -232,18 +235,21 @@
return status;
},
object: "HTMLCanvasElement",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function toBlob(callback){
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify.call(this, "fakedReadout");
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify.call(this, "fakedReadout");
}
return original.apply(fakeCanvas, window.Array.from(args));
}
return original.apply(fakeCanvas, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
},
exportOptions: {allowCallbacks: true}
@ -260,18 +266,21 @@
return status;
},
object: "HTMLCanvasElement",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function mozGetAsFile(callback){
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify.call(this, "fakedReadout");
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (canvasSizeShouldBeFaked(this, prefs)){
var fakeCanvas = getFakeCanvas(window, this, prefs);
if (fakeCanvas !== this){
notify.call(this, "fakedReadout");
}
return original.apply(fakeCanvas, window.Array.from(args));
}
return original.apply(fakeCanvas, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
},
@ -283,26 +292,29 @@
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getImageData(sx, sy, sw, sh){
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
var fakeCanvas;
var context = this;
if (this && this.canvas) {
fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
var fakeCanvas;
var context = this;
if (this && this.canvas) {
fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
}
if (fakeCanvas && fakeCanvas !== this.canvas){
notify.call(this, "fakedReadout");
context = window.HTMLCanvasElement.prototype.getContext.call(
fakeCanvas,
"2d"
);
}
return original.apply(context, window.Array.from(args));
}
if (fakeCanvas && fakeCanvas !== this.canvas){
notify.call(this, "fakedReadout");
context = window.HTMLCanvasElement.prototype.getContext.call(
fakeCanvas,
"2d"
);
else {
return original.apply(this, window.Array.from(args));
}
return original.apply(context, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(arguments));
}
});
};
}
},
@ -314,18 +326,21 @@
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function isPointInPath(x, y){
var rng = randomSupply.getValueRng(1, window);
var originalValue = original.apply(this, window.Array.from(arguments));
if ((typeof originalValue) === "boolean"){
notify.call(this, "fakedReadout");
var index = x + this.width * y;
return original.call(this, rng(x, index), rng(y, index));
}
else {
return originalValue;
}
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
var rng = randomSupply.getValueRng(1, window);
var originalValue = original.apply(this, window.Array.from(args));
if ((typeof originalValue) === "boolean"){
notify.call(this, "fakedReadout");
var index = x + this.width * y;
return original.call(this, rng(x, index), rng(y, index));
}
else {
return originalValue;
}
});
};
}
},
@ -337,18 +352,21 @@
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function isPointInStroke(x, y){
var rng = randomSupply.getValueRng(1, window);
var originalValue = original.apply(this, window.Array.from(arguments));
if ((typeof originalValue) === "boolean"){
notify.call(this, "fakedReadout");
var index = x + this.width * y;
return original.call(this, rng(x, index), rng(y, index));
}
else {
return originalValue;
}
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
var rng = randomSupply.getValueRng(1, window);
var originalValue = original.apply(this, window.Array.from(args));
if ((typeof originalValue) === "boolean"){
notify.call(this, "fakedReadout");
var index = x + this.width * y;
return original.call(this, rng(x, index), rng(y, index));
}
else {
return originalValue;
}
});
};
}
},
@ -360,27 +378,30 @@
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function fillText(str, x, y){
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify.call(this, "fakedInput");
var oldImageData;
try {
// "this" is not trustable - it may be not a context
oldImageData = getImageData(window, this).imageData;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify.call(this, "fakedInput");
var oldImageData;
try {
// "this" is not trustable - it may be not a context
oldImageData = getImageData(window, this).imageData;
}
catch (e){
// nothing to do here
}
// if "this" is not a correct context the next line will throw an error
var ret = original.apply(this, window.Array.from(args));
var newImageData = getImageData(window, this).imageData;
this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
return ret;
}
catch (e){
// nothing to do here
else {
return original.apply(this, window.Array.from(args));
}
// if "this" is not a correct context the next line will throw an error
var ret = original.apply(this, window.Array.from(arguments));
var newImageData = getImageData(window, this).imageData;
this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
return ret;
}
else {
return original.apply(this, window.Array.from(arguments));
}
});
};
}
},
@ -392,27 +413,30 @@
return status;
},
object: "CanvasRenderingContext2D",
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function strokeText(str, x, y){
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify.call(this, "fakedInput");
var oldImageData;
try {
// "this" is not trustable - it may be not a context
oldImageData = getImageData(window, this).imageData;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify.call(this, "fakedInput");
var oldImageData;
try {
// "this" is not trustable - it may be not a context
oldImageData = getImageData(window, this).imageData;
}
catch (e){
// nothing to do here
}
// if "this" is not a correct context the next line will throw an error
var ret = original.apply(this, window.Array.from(args));
var newImageData = getImageData(window, this).imageData;
this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
return ret;
}
catch (e){
// nothing to do here
else {
return original.apply(this, window.Array.from(args));
}
// if "this" is not a correct context the next line will throw an error
var ret = original.apply(this, window.Array.from(arguments));
var newImageData = getImageData(window, this).imageData;
this.putImageData(randomMixImageData(window, oldImageData, newImageData), 0, 0);
return ret;
}
else {
return original.apply(this, window.Array.from(arguments));
}
});
};
}
},
@ -424,21 +448,24 @@
return status;
},
object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function readPixels(x, y, width, height, format, type, pixels){ // eslint-disable-line max-params
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify.call(this, "fakedReadout");
var fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
var {context} = copyCanvasToWebgl(
window,
fakeCanvas,
this instanceof window.WebGLRenderingContext? "webgl": "webgl2"
);
return original.apply(context, window.Array.from(arguments));
}
else {
return original.apply(this, window.Array.from(arguments));
}
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
if (!this || canvasSizeShouldBeFaked(this.canvas, prefs)){
notify.call(this, "fakedReadout");
var fakeCanvas = getFakeCanvas(window, this.canvas, prefs);
var {context} = copyCanvasToWebgl(
window,
fakeCanvas,
this instanceof window.WebGLRenderingContext? "webgl": "webgl2"
);
return original.apply(context, window.Array.from(args));
}
else {
return original.apply(this, window.Array.from(args));
}
});
};
}
}
@ -446,7 +473,17 @@
Object.keys(scope.changedFunctions).forEach(function(key){
scope.changedFunctions[key].api = "canvas";
});
Object.keys(modifiedAudioAPI.changedFunctions).forEach(function(key){
scope.changedFunctions[key] = modifiedAudioAPI.changedFunctions[key];
});
scope.changedGetters = {};
function appendModified(collection){
Object.keys(collection.changedFunctions || {}).forEach(function(key){
scope.changedFunctions[key] = collection.changedFunctions[key];
});
Object.keys(collection.changedGetters || {}).forEach(function(key){
scope.changedGetters[key] = collection.changedGetters[key];
});
}
appendModified(modifiedAudioAPI);
}());

32
lib/modifiedAPIFunctions.js Normal file
View File

@ -0,0 +1,32 @@
/* 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/. */
(function(){
"use strict";
var scope;
if ((typeof exports) !== "undefined"){
scope = exports;
}
else {
window.scope.modifiedAPIFunctions = {};
scope = window.scope.modifiedAPIFunctions;
}
scope.hasType = function hasType(status, type){
return status.type.indexOf(type) !== -1;
};
scope.checkerWrapper = function checkerWrapper(checker, object, args, callback){
const check = checker();
if (check.allow){
if (check.allow === true){
return check.original.apply(object, check.window.Array.from(args));
}
return callback.call(object, args, check);
}
return undefined;
};
}());

98
lib/modifiedAudioAPI.js
View File

@ -16,6 +16,7 @@
const logging = require("./logging");
const {sha256String: hashing} = require("./hash");
const getWrapped = require("sdk/getWrapped");
const {hasType, checkerWrapper} = require("./modifiedAPIFunctions");
var randomSupply = null;
@ -143,10 +144,6 @@
}
}
function hasType(status, type){
return status.type.indexOf(type) !== -1;
}
scope.setRandomSupply = function(supply){
randomSupply = supply;
};
@ -168,79 +165,100 @@
scope.changedFunctions = {
getFloatFrequencyData: {
object: ["AnalyserNode"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getFloatFrequencyData(array){
notifyOnce("getFloatFrequencyData", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeFloat32Array(array, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("getFloatFrequencyData", notify);
var ret = original.apply(this, window.Array.from(args));
fakeFloat32Array(array, window, prefs);
return ret;
});
};
}
},
getByteFrequencyData: {
object: ["AnalyserNode"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getByteFrequencyData(array){
notifyOnce("getByteFrequencyData", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeUint8Array(array, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("getByteFrequencyData", notify);
var ret = original.apply(this, window.Array.from(args));
fakeUint8Array(array, window, prefs);
return ret;
});
};
}
},
getFloatTimeDomainData: {
object: ["AnalyserNode"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getFloatTimeDomainData(array){
notifyOnce("getFloatTimeDomainData", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeFloat32Array(array, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("getFloatTimeDomainData", notify);
var ret = original.apply(this, window.Array.from(args));
fakeFloat32Array(array, window, prefs);
return ret;
});
};
}
},
getByteTimeDomainData: {
object: ["AnalyserNode"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getByteTimeDomainData(array){
notifyOnce("getByteTimeDomainData", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeUint8Array(array, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("getByteTimeDomainData", notify);
var ret = original.apply(this, window.Array.from(args));
fakeUint8Array(array, window, prefs);
return ret;
});
};
}
},
getChannelData: {
object: ["AudioBuffer"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getChannelData(channel){
notifyOnce("getChannelData", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeFloat32Array(ret, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("getChannelData", notify);
var ret = original.apply(this, window.Array.from(args));
fakeFloat32Array(ret, window, prefs);
return ret;
});
};
}
},
copyFromChannel: {
object: ["AudioBuffer"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function copyFromChannel(destination, channelNumber, startInChannel){
notifyOnce("copyFromChannel", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeFloat32Array(destination, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("copyFromChannel", notify);
var ret = original.apply(this, window.Array.from(args));
fakeFloat32Array(destination, window, prefs);
return ret;
});
};
}
},
getFrequencyResponse: {
object: ["BiquadFilterNode", "IIRFilterNode"],
fakeGenerator: function(prefs, notify, window, original){
fakeGenerator: function(checker){
return function getFrequencyResponse(frequencyArray, magResponseOutput, phaseResponseOutput){
notifyOnce("getFrequencyResponse", notify);
var ret = original.apply(this, window.Array.from(arguments));
fakeFloat32Array(magResponseOutput, window, prefs);
fakeFloat32Array(phaseResponseOutput, window, prefs);
return ret;
return checkerWrapper(checker, this, arguments, function(args, check){
var {prefs, notify, window, original} = check;
notifyOnce("getFrequencyResponse", notify);
var ret = original.apply(this, window.Array.from(args));
fakeFloat32Array(magResponseOutput, window, prefs);
fakeFloat32Array(phaseResponseOutput, window, prefs);
return ret;
});
};
}
},

1
manifest.json
View File

@ -32,6 +32,7 @@
"lib/colorStatistics.js",
"lib/webgl.js",
"lib/hash.js",
"lib/modifiedAPIFunctions.js",
"lib/modifiedAudioAPI.js",
"lib/modifiedAPI.js",
"lib/randomSupplies.js",

2
releaseNotes.txt
View File

@ -8,7 +8,7 @@ Version 0.4.6:
- Settings can be hidden
fixes:
-
- make function replacements not detectable
Version 0.4.5c:
new features: