security-and-privacy/CanvasBlocker
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CanvasBlocker
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webGL: added image hash tests

This commit is contained in:
kkapsner 2020-05-21 00:11:25 +02:00
parent a79c4ec8c5
commit da5a9f4509
2 changed files with 155 additions and 22 deletions
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9
test/webGL-Test.html
View File

@ -5,6 +5,11 @@
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<link href="testIcon.svg" type="image/png" rel="icon">
<link href="testIcon.svg" type="image/png" rel="shortcut icon">
<style>
th {
text-align: right;
}
</style>
</head>
<body>
<h1>webGL test</h1>
@ -12,12 +17,16 @@
<ul>
<li>both webGL versions should be supported (unless you disabled it in the browser settings) - reload if one is showing "not supported"</li>
<li>upon page reload the hashes change (depending on CanvasBlocker settings - e.g. not in the stealth preset)</li>
<li>all the image hashes should be the same (offscreen workers are not yet protected by CanvasBlocker)</li>
<li>upon page reload some of the parameters (depending on CanvasBlocker settings - e.g. not in the stealth preset)</li>
<li>the "vendor" und "renderer" (also unmasked) parameters reflect the values you chose for them</li>
</ul>
<h3>Support</h3>
<div id="output"></div>
<h3>Hashes</h3>
<div id="hashes"></div>
<h3>Parameters</h3>
<div id="parameters"></div>
<script src="testAPI.js"></script>
<script src="webGL-Test.js"></script>
</body></html>

168
test/webGL-Test.js
View File

@ -1,3 +1,4 @@
/* globals testAPI */
(function(){
"use strict";
@ -45,13 +46,61 @@
return parameters;
}
["webgl", "webgl2"].forEach(async function(context, index){
function createHashRow(hashTable, rowName){
const row = document.createElement("tr");
hashTable.appendChild(row);
const nameCell = document.createElement("th");
nameCell.textContent = rowName;
row.appendChild(nameCell);
const valueCell = document.createElement("td");
valueCell.innerHTML = "<i>computing</i>";
row.appendChild(valueCell);
return valueCell;
}
function fillWebGlContext(context){
// taken from https://github.com/Valve/fingerprintjs2/blob/master/fingerprint2.js
const vertexShaderTemplate = "attribute vec2 attrVertex;varying vec2 varyingTexCoordinate;" +
"uniform vec2 uniformOffset;void main(){varyingTexCoordinate=attrVertex+uniformOffset;" +
"gl_Position=vec4(attrVertex,0,1);}";
const fragmentShaderTemplate = "precision mediump float;varying vec2 varyingTexCoordinate;" +
"void main() {gl_FragColor=vec4(varyingTexCoordinate,0,1);}";
const vertexPosBuffer = context.createBuffer();
context.bindBuffer(context.ARRAY_BUFFER, vertexPosBuffer);
const vertices = new Float32Array([-0.2, -0.9, 0, 0.4, -0.26, 0, 0, 0.732134444, 0]);
context.bufferData(context.ARRAY_BUFFER, vertices, context.STATIC_DRAW);
vertexPosBuffer.itemSize = 3;
vertexPosBuffer.numItems = 3;
const program = context.createProgram();
const vertexShader = context.createShader(context.VERTEX_SHADER);
context.shaderSource(vertexShader, vertexShaderTemplate);
context.compileShader(vertexShader);
const fragmentShader = context.createShader(context.FRAGMENT_SHADER);
context.shaderSource(fragmentShader, fragmentShaderTemplate);
context.compileShader(fragmentShader);
context.attachShader(program, vertexShader);
context.attachShader(program, fragmentShader);
context.linkProgram(program);
context.useProgram(program);
program.vertexPosAttrib = context.getAttribLocation(program, "attrVertex");
program.offsetUniform = context.getUniformLocation(program, "uniformOffset");
context.enableVertexAttribArray(program.vertexPosArray);
context.vertexAttribPointer(program.vertexPosAttrib, vertexPosBuffer.itemSize, context.FLOAT, !1, 0, 0);
context.uniform2f(program.offsetUniform, 1, 1);
context.drawArrays(context.TRIANGLE_STRIP, 0, vertexPosBuffer.numItems);
}
async function testSupport(context, index){
const canvas = document.createElement("canvas");
canvas.width = 11;
canvas.height = 13;
const output = document.createElement("div");
document.getElementById("output").appendChild(output);
try {
const canvas = document.createElement("canvas");
canvas.width = 11;
canvas.height = 13;
const gl = canvas.getContext(context) || canvas.getContext("experimental-" + context);
// paint it completely black
@ -67,6 +116,26 @@
max = Math.max(max, values[pixels[i]]);
}
output.textContent = context + ": " +
(max !== 3 * values[255]? "": "not ") + "supported ";
output.title = JSON.stringify(values);
}
catch (error){
output.textContent = context + ": ERROR";
output.title = error;
}
}
async function testParameters(context, hashTable){
const canvas = document.createElement("canvas");
canvas.width = 11;
canvas.height = 13;
const hashCell = createHashRow(hashTable, "parameter");
try {
const gl = canvas.getContext(context) || canvas.getContext("experimental-" + context);
const parameters = getParameters(gl);
if (context === "webgl2"){
const parameterOutput = document.createElement("table");
@ -77,27 +146,82 @@
parameterOutput.appendChild(parameterRow);
});
}
const hashBytes = await crypto.subtle.digest("SHA-256", new TextEncoder("utf-8")
.encode(parameters.map(function(parameter){
return parameter.name + ": " + parameter.value;
}).join(",")));
const chunks = [];
(new Uint32Array(hashBytes)).forEach(function(num){
chunks.push(num.toString(16));
});
const hash = chunks.map(function(chunk){
return "0".repeat(8 - chunk.length) + chunk;
}).join("");
output.textContent = context + ": " +
(max !== 3 * values[255]? "": "not ") + "supported " +
"(parameter hash: " + hash + ")";
output.title = JSON.stringify(values);
hashCell.textContent = await testAPI.hash(parameters.map(function(parameter){
return parameter.name + ": " + parameter.value;
}).join(","));
}
catch (error){
output.textContent = context + ": ERROR";
output.title = error;
hashCell.textContent = "ERROR";
hashCell.title = error;
}
}
async function createImageHash(context, hashTable){
return Promise.all([function(){
const canvas = document.createElement("canvas");
canvas.width = 300;
canvas.height = 150;
return canvas;
}, function(){
if (window.OffscreenCanvas){
return new OffscreenCanvas(300, 150);
}
return null;
}].map(async function(getter){
const canvas = getter();
if (canvas){
const hashCell = createHashRow(hashTable, "image" + (canvas.toDataURL? "": " (offscreen)"));
try {
const gl = canvas.getContext(context) || canvas.getContext("experimental-" + context);
fillWebGlContext(gl);
if (canvas.convertToBlob || canvas.toBlob){
const blob = await (canvas.convertToBlob? canvas.convertToBlob(): (canvas.toBlob.length?
new Promise(function(resolve){canvas.toBlob(resolve);}):
canvas.toBlob()
));
hashCell.textContent = await testAPI.hash(await testAPI.readBlob(blob));
}
}
catch (error){
console.log(error);
}
}
return false;
}));
}
async function createWorkerImageHash(context, hashTable){
if (window.Worker && window.OffscreenCanvas){
const hashCell = createHashRow(hashTable, "image (offscreen worker)");
const url = new URL("./testAPI.js", location);
hashCell.textContent = await testAPI.runInWorker(async function getHash(contextType){
const canvas = new OffscreenCanvas(300, 150);
const context = canvas.getContext(contextType);
fillWebGlContext(context);
return await testAPI.hash(
await testAPI.readBlob(
canvas.convertToBlob?
await canvas.convertToBlob():
await canvas.toBlob()
)
);
}, [context], [url, fillWebGlContext]);
}
}
["webgl", "webgl2"].forEach(async function(context, index){
testSupport(context, index);
const hashOutput = document.createElement("div");
document.getElementById("hashes").appendChild(hashOutput);
hashOutput.textContent = context + ": ";
const table = document.createElement("table");
hashOutput.appendChild(table);
testParameters(context, table);
createImageHash(context, table);
createWorkerImageHash(context, table);
});
}());