security-and-privacy/CanvasBlocker
security-and-privacy/CanvasBlocker
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Code Releases Activity

Added askReadout

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This commit is contained in:
kkapsner 2014-10-11 01:46:47 +02:00
parent 23b5d7672c
commit 7da2a94030
6 changed files with 115 additions and 103 deletions
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192
data/inject.js
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@ -1,4 +1,4 @@
/* global self, window, console, unsafeWindow */
/* global self, window, console, unsafeWindow, exportFunction */
(function(){
"use strict";
@ -12,7 +12,12 @@
}
},
readAPI: {
status: "allow"
status: "allow",
askStatus: {
askOnce: false,
alreadyAsked: false,
answer: null
}
}
};
@ -62,108 +67,86 @@
return bytes;
}());
var originalToDataURL = unsafeWindow.HTMLCanvasElement.prototype.toDataURL;
Object.defineProperty(
unsafeWindow.HTMLCanvasElement.prototype,
"toDataURL",
{
enumerable: true,
configureable: false,
get: exportFunction(function(){
switch (blockMode.readAPI.status){
case "allow":
return originalToDataURL;
case "block":
default:
return exportFunction(
function(){
var type = arguments[0] || "image/png";
return "data:" + type + ";base64," + btoa(randomImage);
},
unsafeWindow
);
// Readout API blocking
var fakeFunctions = {
toDataURL: {
object: unsafeWindow.HTMLCanvasElement,
func: function(){
var type = arguments[0] || "image/png";
return "data:" + type + ";base64," + btoa(randomImage);
}
},
toBlob: {
object: unsafeWindow.HTMLCanvasElement,
func: function(callback){
var type = arguments[0] || "image/png";
var blob = new window.Blob(randomImage, {type: type});
callback(blob);
},
exportOptions: {allowCallbacks: true}
},
mozGetAsFile: {
object: unsafeWindow.HTMLCanvasElement,
func: undef
},
getImageData: {
object: unsafeWindow.CanvasRenderingContext2D,
func: function(sx, sy, sw, sh){
var imageData = new window.ImageData(sw, sh);
var l = sw * sh * 4;
for (var i = 0; i < l; i += 1){
imageData.data[i] = Math.floor(
Math.random() * 256
);
}
}, unsafeWindow)
return imageData;
}
}
);
};
var originalToBlob = unsafeWindow.HTMLCanvasElement.prototype.toBlob;
Object.defineProperty(
unsafeWindow.HTMLCanvasElement.prototype,
"toBlob",
{
enumerable: true,
configureable: false,
get: exportFunction(function(){
switch (blockMode.readAPI.status){
case "allow":
return originalToBlob;
case "block":
default:
return exportFunction(
function(callback){
var type = arguments[0] || "image/png";
var blob = new window.Blob(randomImage, {type: type});
callback(blob);
},
unsafeWindow,
{allowCallbacks: true}
);
}
}, unsafeWindow)
}
);
Object.keys(fakeFunctions).forEach(function(name){
var fakeFunction = fakeFunctions[name];
var original = fakeFunction.object.prototype[name];
Object.defineProperty(
fakeFunction.object.prototype,
name,
{
enumerable: true,
configureable: false,
get: exportFunction(function(){
var status = blockMode.readAPI.status;
if (status === "ask"){
var askStatus = blockMode.readAPI.askStatus;
var allow;
if (askStatus.askOnce && askStatus.alreadyAsked){
// console.log("already asked");
allow = askStatus.answer;
}
else {
// console.log("asking");
allow = window.confirm(_("askForReadoutPermission"));
askStatus.alreadyAsked = true;
askStatus.answer = allow;
}
status = allow? "allow": "block";
}
switch (status){
case "allow":
return original;
case "block":
default:
return exportFunction(
fakeFunction.func,
unsafeWindow,
fakeFunction.exportOptions
);
}
}, unsafeWindow)
}
);
});
var originalMozGetAsFile = unsafeWindow.HTMLCanvasElement.prototype.mozGetAsFile;
Object.defineProperty(
unsafeWindow.HTMLCanvasElement.prototype,
"mozGetAsFile",
{
enumerable: true,
configureable: false,
get: exportFunction(function(){
switch (blockMode.readAPI.status){
case "allow":
return originalMozGetAsFile;
case "block":
default:
undef
}
}, unsafeWindow)
}
);
var originalGetImageData = unsafeWindow.CanvasRenderingContext2D.prototype.getImageData;
Object.defineProperty(
unsafeWindow.CanvasRenderingContext2D.prototype,
"getImageData",
{
enumerable: true,
configureable: false,
get: exportFunction(function(){
switch (blockMode.readAPI.status){
case "allow":
return originalGetImageData;
case "block":
default:
return exportFunction(
function(sx, sy, sw, sh){
var imageData = new window.ImageData(sw, sh);
var l = sw * sh * 4;
for (var i = 0; i < l; i += 1){
imageData.data[i] = Math.floor(
Math.random() * 256
);
}
return imageData;
},
unsafeWindow
);
}
}, unsafeWindow)
}
);
// Translation
var _ = function(name){
return _[name] || name;
};
@ -171,6 +154,8 @@
_[name] = translation;
});
// Communication with main.js
function checkPDF(blocking){
if (document.contentType.match(/\/pdf$/i)){
self.port.emit("isPDF", blocking);
@ -198,6 +183,13 @@
blockMode.readAPI.status = "block";
}
});
self.port.on("askReadout", function(force, askOnce){
if (force || !checkPDF("askReadout")){
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "ask";
blockMode.readAPI.askStatus.askOnce = askOnce;
}
});
self.port.on("unblock", function(){
blockMode.getContext.status = "allow";
blockMode.readAPI.status = "allow";