Bug 1670447: Deprecate randomDataOnCanvasExtract. r=tjr

Differential Revision: https://phabricator.services.mozilla.com/D226821
2024-11-23 21:01:08 +00:00 · 2024-11-06 13:32:22 +00:00 · 2024-11-06 13:32:22 +00:00 · d8ad1f1b44
commit d8ad1f1b44
parent f7f8b28ee7
3 changed files with 28 additions and 150 deletions
--- a/browser/base/content/test/permissions/browser_canvas_fingerprinting_resistance.js
+++ b/browser/base/content/test/permissions/browser_canvas_fingerprinting_resistance.js
@ -3,9 +3,7 @@
 * required for canvas data extraction.
 * This tests whether the site permission prompt for canvas data extraction
 * works properly.
- * When "privacy.resistFingerprinting.randomDataOnCanvasExtract" is true,
- * canvas data extraction results in random data, and when it is false, canvas
- * data extraction results in all-white data.
+ * Canvas data extraction should result in random data.
 */
 "use strict";

@ -48,8 +46,6 @@ function initTab() {
    return canvas;
  };

-  let placeholder = drawCanvas("white");
-  contentWindow.kPlaceholderData = placeholder.toDataURL();
  let canvas = drawCanvas("cyan", "canvas-id-canvas");
  contentWindow.kPlacedData = canvas.toDataURL();
  is(
@ -57,17 +53,9 @@ function initTab() {
    contentWindow.kPlacedData,
    "privacy.resistFingerprinting = false, canvas data == placed data"
  );
-  isnot(
-    canvas.toDataURL(),
-    contentWindow.kPlaceholderData,
-    "privacy.resistFingerprinting = false, canvas data != placeholder data"
-  );
 }

-function enableResistFingerprinting(
-  randomDataOnCanvasExtract,
-  autoDeclineNoInput
-) {
+function enableResistFingerprinting(autoDeclineNoInput) {
  return SpecialPowers.pushPrefEnv({
    set: [
      ["privacy.fingerprintingProtection", true],
@ -78,10 +66,6 @@ function enableResistFingerprinting(
            ? ",+CanvasExtractionBeforeUserInputIsBlocked"
            : ""),
      ],
-      [
-        "privacy.resistFingerprinting.randomDataOnCanvasExtract",
-        randomDataOnCanvasExtract,
-      ],
    ],
  });
 }
@ -94,7 +78,7 @@ function promisePopupHidden() {
  return BrowserTestUtils.waitForEvent(PopupNotifications.panel, "popuphidden");
 }

-function extractCanvasData(randomDataOnCanvasExtract, grantPermission) {
+function extractCanvasData(grantPermission) {
  let contentWindow = content.wrappedJSObject;
  let canvas = contentWindow.document.getElementById("canvas-id-canvas");
  let canvasData = canvas.toDataURL();
@ -104,51 +88,18 @@ function extractCanvasData(randomDataOnCanvasExtract, grantPermission) {
      contentWindow.kPlacedData,
      "privacy.resistFingerprinting = true, permission granted, canvas data == placed data"
    );
-    if (!randomDataOnCanvasExtract) {
-      isnot(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = false, permission granted, canvas data != placeholderdata"
-      );
-    }
  } else if (grantPermission === false) {
    isnot(
      canvasData,
      contentWindow.kPlacedData,
      "privacy.resistFingerprinting = true, permission denied, canvas data != placed data"
    );
-    if (!randomDataOnCanvasExtract) {
-      is(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = false, permission denied, canvas data == placeholderdata"
-      );
-    } else {
-      isnot(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = true, permission denied, canvas data != placeholderdata"
-      );
-    }
  } else {
    isnot(
      canvasData,
      contentWindow.kPlacedData,
      "privacy.resistFingerprinting = true, requesting permission, canvas data != placed data"
    );
-    if (!randomDataOnCanvasExtract) {
-      is(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = false, requesting permission, canvas data == placeholderdata"
-      );
-    } else {
-      isnot(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = true, requesting permission, canvas data != placeholderdata"
-      );
-    }
  }
 }

@ -170,19 +121,11 @@ function testPermission() {
  return Services.perms.testPermissionFromPrincipal(kPrincipal, kPermission);
 }

-async function withNewTabNoInput(
-  randomDataOnCanvasExtract,
-  grantPermission,
-  browser
-) {
+async function withNewTabNoInput(grantPermission, browser) {
  await SpecialPowers.spawn(browser, [], initTab);
-  await enableResistFingerprinting(randomDataOnCanvasExtract, false);
+  await enableResistFingerprinting(false);
  let popupShown = promisePopupShown();
-  await SpecialPowers.spawn(
-    browser,
-    [randomDataOnCanvasExtract],
-    extractCanvasData
-  );
+  await SpecialPowers.spawn(browser, [], extractCanvasData);
  await popupShown;
  let popupHidden = promisePopupHidden();
  if (grantPermission) {
@ -194,34 +137,28 @@ async function withNewTabNoInput(
    await popupHidden;
    is(testPermission(), Services.perms.DENY_ACTION, "permission denied");
  }
-  await SpecialPowers.spawn(
-    browser,
-    [randomDataOnCanvasExtract, grantPermission],
-    extractCanvasData
-  );
+  await SpecialPowers.spawn(browser, [grantPermission], extractCanvasData);
  await SpecialPowers.popPrefEnv();
 }

-async function doTestNoInput(randomDataOnCanvasExtract, grantPermission) {
+async function doTestNoInput(grantPermission) {
  await BrowserTestUtils.withNewTab(
    kUrl,
-    withNewTabNoInput.bind(null, randomDataOnCanvasExtract, grantPermission)
+    withNewTabNoInput.bind(null, grantPermission)
  );
  Services.perms.removeFromPrincipal(kPrincipal, kPermission);
 }

 // With auto-declining disabled (not the default)
 // Tests clicking "Don't Allow" button of the permission prompt.
-add_task(doTestNoInput.bind(null, true, false));
-add_task(doTestNoInput.bind(null, false, false));
+add_task(doTestNoInput.bind(null, false));

 // Tests clicking "Allow" button of the permission prompt.
-add_task(doTestNoInput.bind(null, true, true));
-add_task(doTestNoInput.bind(null, false, true));
+add_task(doTestNoInput.bind(null, true));

-async function withNewTabAutoBlockNoInput(randomDataOnCanvasExtract, browser) {
+async function withNewTabAutoBlockNoInput(browser) {
  await SpecialPowers.spawn(browser, [], initTab);
-  await enableResistFingerprinting(randomDataOnCanvasExtract, true);
+  await enableResistFingerprinting(true);

  let noShowHandler = () => {
    ok(false, "The popup notification should not show in this case.");
@ -235,11 +172,7 @@ async function withNewTabAutoBlockNoInput(randomDataOnCanvasExtract, browser) {
  );

  // Try to extract canvas data without user inputs.
-  await SpecialPowers.spawn(
-    browser,
-    [randomDataOnCanvasExtract],
-    extractCanvasData
-  );
+  await SpecialPowers.spawn(browser, [], extractCanvasData);

  await promisePopupObserver;
  info("There should be no popup shown on the panel.");
@ -260,20 +193,16 @@ async function withNewTabAutoBlockNoInput(randomDataOnCanvasExtract, browser) {
  await SpecialPowers.popPrefEnv();
 }

-async function doTestAutoBlockNoInput(randomDataOnCanvasExtract) {
+async function doTestAutoBlockNoInput() {
  await BrowserTestUtils.withNewTab(
    kUrl,
-    withNewTabAutoBlockNoInput.bind(null, randomDataOnCanvasExtract)
+    withNewTabAutoBlockNoInput.bind(null)
  );
 }

-add_task(doTestAutoBlockNoInput.bind(null, true));
-add_task(doTestAutoBlockNoInput.bind(null, false));
+add_task(doTestAutoBlockNoInput.bind(null));

-function extractCanvasDataUserInput(
-  randomDataOnCanvasExtract,
-  grantPermission
-) {
+function extractCanvasDataUserInput(grantPermission) {
  let contentWindow = content.wrappedJSObject;
  let canvas = contentWindow.document.getElementById("canvas-id-canvas");
  let canvasData = canvas.toDataURL();
@ -283,61 +212,24 @@ function extractCanvasDataUserInput(
      contentWindow.kPlacedData,
      "privacy.resistFingerprinting = true, permission granted, canvas data == placed data"
    );
-    if (!randomDataOnCanvasExtract) {
-      isnot(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = false, permission granted, canvas data != placeholderdata"
-      );
-    }
  } else if (grantPermission === false) {
    isnot(
      canvasData,
      contentWindow.kPlacedData,
      "privacy.resistFingerprinting = true, permission denied, canvas data != placed data"
    );
-    if (!randomDataOnCanvasExtract) {
-      is(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = false, permission denied, canvas data == placeholderdata"
-      );
-    } else {
-      isnot(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = true, permission denied, canvas data != placeholderdata"
-      );
-    }
  } else {
    isnot(
      canvasData,
      contentWindow.kPlacedData,
      "privacy.resistFingerprinting = true, requesting permission, canvas data != placed data"
    );
-    if (!randomDataOnCanvasExtract) {
-      is(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = false, requesting permission, canvas data == placeholderdata"
-      );
-    } else {
-      isnot(
-        canvasData,
-        contentWindow.kPlaceholderData,
-        "privacy.resistFingerprinting = true and randomDataOnCanvasExtract = true, requesting permission, canvas data != placeholderdata"
-      );
-    }
  }
 }

-async function withNewTabInput(
-  randomDataOnCanvasExtract,
-  grantPermission,
-  browser
-) {
+async function withNewTabInput(grantPermission, browser) {
  await SpecialPowers.spawn(browser, [], initTab);
-  await enableResistFingerprinting(randomDataOnCanvasExtract, true);
+  await enableResistFingerprinting(true);
  let popupShown = promisePopupShown();
  await SpecialPowers.spawn(browser, [], function () {
    E10SUtils.wrapHandlingUserInput(content, true, function () {
@ -358,25 +250,23 @@ async function withNewTabInput(
  }
  await SpecialPowers.spawn(
    browser,
-    [randomDataOnCanvasExtract, grantPermission],
+    [grantPermission],
    extractCanvasDataUserInput
  );
  await SpecialPowers.popPrefEnv();
 }

-async function doTestInput(randomDataOnCanvasExtract, grantPermission) {
+async function doTestInput(grantPermission) {
  await BrowserTestUtils.withNewTab(
    kUrl,
-    withNewTabInput.bind(null, randomDataOnCanvasExtract, grantPermission)
+    withNewTabInput.bind(null, grantPermission)
  );
  Services.perms.removeFromPrincipal(kPrincipal, kPermission);
 }

 // With auto-declining enabled (the default)
 // Tests clicking "Don't Allow" button of the permission prompt.
-add_task(doTestInput.bind(null, true, false));
-add_task(doTestInput.bind(null, false, false));
+add_task(doTestInput.bind(null, false));

 // Tests clicking "Allow" button of the permission prompt.
-add_task(doTestInput.bind(null, true, true));
-add_task(doTestInput.bind(null, false, true));
+add_task(doTestInput.bind(null, true));
--- a/dom/canvas/GeneratePlaceholderCanvasData.h
+++ b/dom/canvas/GeneratePlaceholderCanvasData.h
@ -17,18 +17,13 @@
 namespace mozilla::dom {

 /**
- * When privacy.resistFingerprinting.randomDataOnCanvasExtract is true, tries
- * to generate random data for placeholder canvas by sampling
- * RANDOM_BYTES_TO_SAMPLE bytes and then returning it. If this fails or if
- * privacy.resistFingerprinting.randomDataOnCanvasExtract is false, returns
- * nullptr.
+ * This function tries to generate random data for placeholder canvas by
+ * sampling RANDOM_BYTES_TO_SAMPLE bytes and then returning it. If it fails,
+ * returns nullptr.
 *
 * @return uint8_t*  output buffer
 */
 inline uint8_t* TryToGenerateRandomDataForPlaceholderCanvasData() {
-  if (!StaticPrefs::privacy_resistFingerprinting_randomDataOnCanvasExtract()) {
-    return nullptr;
-  }
  nsresult rv;
  nsCOMPtr<nsIRandomGenerator> rg =
      do_GetService("@mozilla.org/security/random-generator;1", &rv);
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@ -14953,13 +14953,6 @@
  value: false
  mirror: always

-# Whether canvas extraction should result in random data. If false, canvas
-# extraction results in all-white, opaque pixel data.
- name: privacy.resistFingerprinting.randomDataOnCanvasExtract
-  type: RelaxedAtomicBool
-  value: true
-  mirror: always
-
 # The log level for browser console messages logged in RFPHelper.sys.mjs. Change to
 # 'All' and restart to see the messages.
 - name: privacy.resistFingerprinting.jsmloglevel