Commit 73c7fe8d authored by Fatih's avatar Fatih
Browse files

Bug 1918690: Improve canvas randomization permission test. r=tjr 

Differential Revision: https://phabricator.services.mozilla.com/D222121
parent c90c9255

toolkit/components/resistfingerprinting/tests/browser/browser_canvas_randomization_permission.js

+100 −28
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


/**

 * Bug 1896175 - Testing canvas randomization with read canvas permission granted.

 *

 * Bug 1918690 - Extend canvas randomization permission test

 */



const emptyPage =
@@ -13,11 +13,11 @@ const emptyPage = 
    "https://example.com"

  ) + "empty.html";



const TRUE_VALUE = "255,0,0,255,0,255,0,255,0,0,255,255";



function getImageData(tab) {

  const extractCanvas = function () {

    const canvas = document.createElement("canvas");

function getImageData(tab, isOffscreen, method) {

  const extractCanvas = function (isOffscreen, method) {

    const canvas = isOffscreen

      ? new OffscreenCanvas(3, 1)

      : document.createElement("canvas");

    const ctx = canvas.getContext("2d");



    ctx.fillStyle = "rgb(255, 0, 0)";
@@ -27,10 +27,30 @@ function getImageData(tab) { 
    ctx.fillStyle = "rgb(0, 0, 255)";

    ctx.fillRect(2, 0, 1, 1);



    if (method === "getImageData") {

      return ctx.getImageData(0, 0, 3, 1).data.join(",");

    } else if (method === "toDataURL") {

      return canvas.toDataURL();

    } else if (method === "toBlob") {

      return new Promise((resolve, reject) => {

        if (isOffscreen) {

          canvas.convertToBlob().then(resolve, reject);

        } else {

          canvas.toBlob(resolve, "image/png");

        }

      }).then(blob => {

        const reader = new FileReader();

        reader.readAsDataURL(blob);

        const { promise, resolve, reject } = Promise.withResolvers();

        reader.onload = () => resolve(reader.result);

        reader.onerror = reject;

        return promise;

      });

    }

    return null;

  };



  const extractCanvasExpr = `(${extractCanvas.toString()})();`;

  const extractCanvasExpr = `(${extractCanvas.toString()})(${isOffscreen}, "${method}");`;



  return SpecialPowers.spawn(

    tab.linkedBrowser,
@@ -39,10 +59,21 @@ function getImageData(tab) { 
  );

}



add_task(async function test_no_permission() {

// Test cases: [isOffscreen, method, true value]

const TEST_CASES = [

  // HTMLCanvasElement

  [false, "getImageData", null],

  [false, "toDataURL", null],

  [false, "toBlob", null],

  // OffscreenCanvas

  [true, "getImageData", null],

  [true, "toBlob", null],

];



add_setup(async function setup() {

  await SpecialPowers.pushPrefEnv({

    set: [

      ["privacy.resistFingerprinting", true],

      ["privacy.resistFingerprinting", false],

      ["privacy.fingerprintingProtection", false],

    ],

  });
@@ -53,19 +84,26 @@ add_task(async function test_no_permission() { 
    forceNewProcess: true,

  });



  const imageData = await getImageData(tab);



  isnot(imageData, TRUE_VALUE, "Image data was randomized.");

  for (let i = 0; i < TEST_CASES.length; i++) {

    const test_case = TEST_CASES[i];

    const [isOffscreen, method] = test_case;

    const imageData = await getImageData(tab, isOffscreen, method);

    test_case[2] = imageData;

  }



  BrowserTestUtils.removeTab(tab);

  await SpecialPowers.popPrefEnv();

});



add_task(async function test_permission() {

async function runTest(permissionGranted, isRFP) {

  await SpecialPowers.pushPrefEnv({

    set: [

      ["privacy.resistFingerprinting", true],

      ["privacy.fingerprintingProtection", false],

      ["privacy.resistFingerprinting", isRFP],

      ["privacy.fingerprintingProtection", !isRFP],

      [

        "privacy.fingerprintingProtection.overrides",

        "-AllTargets,+CanvasRandomization,+CanvasImageExtractionPrompt",

      ],

    ],

  });
@@ -75,6 +113,7 @@ add_task(async function test_permission() { 
    forceNewProcess: true,

  });



  if (permissionGranted) {

    await SpecialPowers.pushPermissions([

      {

        type: "canvas",
@@ -82,12 +121,45 @@ add_task(async function test_permission() { 
        context: emptyPage,

      },

    ]);

  }



  const imageData = await getImageData(tab);



  is(imageData, TRUE_VALUE, "Image data was not randomized.");

  for (let i = 0; i < TEST_CASES.length; i++) {

    const test_case = TEST_CASES[i];

    const [isOffscreen, method, trueValue] = test_case;

    const imageData = await getImageData(tab, isOffscreen, method);

    const message = `Image data was ${

      permissionGranted ? "not " : ""

    }randomized for ${method} on ${

      isOffscreen ? "OffscreenCanvas" : "HTMLCanvasElement"

    }.`;

    if (isOffscreen) {

      // Offscreen canvas doesn't respect the permission.

      continue;

    }

    permissionGranted

      ? is(imageData, trueValue, message)

      : isnot(imageData, trueValue, message);

  }



  BrowserTestUtils.removeTab(tab);

  if (permissionGranted) {

    await SpecialPowers.popPermissions();

  }

  BrowserTestUtils.removeTab(tab);

  await SpecialPowers.popPrefEnv();

}



add_task(async function test_rfp_no_permission() {

  await runTest(false, true);

});



add_task(async function test_rfp_permission() {

  await runTest(true, true);

});



add_task(async function test_fpp_no_permission() {

  await runTest(false, false);

});



add_task(async function test_fpp_permission() {

  await runTest(true, false);

});