security-and-privacy/CanvasBlocker
security-and-privacy/CanvasBlocker
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Removed bug with faking webgl and added readPixels for webgl2.

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Fixes #96 and #97.
This commit is contained in:
kkapsner 2016-12-26 14:36:01 +01:00
parent 6748771402
commit 6d7a9fc22a
2 changed files with 63 additions and 54 deletions
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8
lib/intercept.js
View File

@ -26,11 +26,12 @@
if (siteStatus.mode !== "allow"){ if (siteStatus.mode !== "allow"){
apiNames.forEach(function(name){ apiNames.forEach(function(name){
var changedFunction = changedFunctions[name]; var changedFunction = changedFunctions[name];
var original = window.wrappedJSObject[changedFunction.object].prototype[name];
if (changedFunction.getStatus(undefined, siteStatus).active){ if (changedFunction.getStatus(undefined, siteStatus).active){
(Array.isArray(changedFunction.object)? changedFunction.object: [changedFunction.object]).forEach(function(object){
var original = window.wrappedJSObject[object].prototype[name];
Object.defineProperty( Object.defineProperty(
window.wrappedJSObject[changedFunction.object].prototype, window.wrappedJSObject[object].prototype,
name, name,
{ {
enumerable: true, enumerable: true,
@ -76,6 +77,7 @@
} }
} }
); );
});
} }
}); });
} }

25
lib/modifiedAPI.js
View File

@ -17,30 +17,37 @@
window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl2"); window.HTMLCanvasElement.prototype.getContext.call(canvas, "experimental-webgl2");
} }
function getImageData(window, context){ function getImageData(window, context){
var imageData;
var source;
if (context instanceof window.CanvasRenderingContext2D){ if (context instanceof window.CanvasRenderingContext2D){
return window.CanvasRenderingContext2D.prototype.getImageData.call(context, 0, 0, context.canvas.width, context.canvas.height); imageData = window.CanvasRenderingContext2D.prototype.getImageData.call(context, 0, 0, context.canvas.width, context.canvas.height);
source = imageData.data;
} }
else { else {
var imageData = new window.wrappedJSObject.ImageData(context.canvas.width, context.canvas.height); var imageData = new window.wrappedJSObject.ImageData(context.canvas.width, context.canvas.height);
var source = new Uint8Array(imageData.data.length);
window.WebGLRenderingContext.prototype.readPixels.call( window.WebGLRenderingContext.prototype.readPixels.call(
context, context,
0, 0, context.canvas.width, context.canvas.height, 0, 0, context.canvas.width, context.canvas.height,
context.RGBA, context.UNSIGNED_BYTE, context.RGBA, context.UNSIGNED_BYTE,
imageData.data source
); );
return imageData;
} }
return {
imageData,
source
};
} }
function getFakeCanvas(window, original){ function getFakeCanvas(window, original){
var context = getContext(window, original); var context = getContext(window, original);
var imageData = getImageData(window, context); var {imageData, source} = getImageData(window, context);
var data = imageData.data; var desc = imageData.data;
var l = data.length; var l = desc.length;
var rng = randomSupply.getRng(l, window); var rng = randomSupply.getRng(l, window);
for (var i = 0; i < l; i += 1){ for (var i = 0; i < l; i += 10){
data[i] = rng(data[i], i); desc[i] = rng(source[i], i);
} }
var canvas = original.cloneNode(true); var canvas = original.cloneNode(true);
context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d"); context = window.HTMLCanvasElement.prototype.getContext.call(canvas, "2d");
@ -249,7 +256,7 @@
status.active = hasType(status, "readout") || hasType(status, "input"); status.active = hasType(status, "readout") || hasType(status, "input");
return status; return status;
}, },
object: "WebGLRenderingContext", object: ["WebGLRenderingContext", "WebGL2RenderingContext"],
fakeGenerator: function(prefs, notify){ fakeGenerator: function(prefs, notify){
return function readPixels(x, y, width, height, format, type, pixels){ return function readPixels(x, y, width, height, format, type, pixels){
// not able to use the getFakeCanvas function because the context type is wrong... // not able to use the getFakeCanvas function because the context type is wrong...