tor-browser

commit ebfba9ae402e48be88128ad9132d21129210113e
parent ef5b800cf0a9c3990d1c6f350790da3d2c53f90e
Author: Pier Angelo Vendrame <pierov@torproject.org>
Date:   Thu,  6 Nov 2025 14:18:32 +0000

Bug 1998435 - Do not reset the default zoom when clearing the FFP state. r=manuel

Differential Revision: https://phabricator.services.mozilla.com/D271446

Diffstat:
M
browser/components/resistfingerprinting/test/browser/browser_bug1975753_site_specific_zoom_level.js
 | 
24
++++++++++++++++++++++--
M
toolkit/components/cleardata/ClearDataService.sys.mjs
 | 
66
+++++++++++++++++++++---------------------------------------------

2 files changed, 43 insertions(+), 47 deletions(-)
diff --git a/browser/components/resistfingerprinting/test/browser/browser_bug1975753_site_specific_zoom_level.js b/browser/components/resistfingerprinting/test/browser/browser_bug1975753_site_specific_zoom_level.js
@@ -3,10 +3,14 @@
 const PATH_NET = TEST_PATH + "file_dummy.html";
 const PATH_ORG = PATH_NET.replace("example.net", "example.org");
 
-add_task(async function () {
+async function runTest(defaultZoom) {
   let tab1, tab1Zoom;
 
   tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, PATH_NET);
+
+  tab1Zoom = ZoomManager.getZoomForBrowser(tab1.linkedBrowser);
+  is(tab1Zoom, defaultZoom, "We are starting with the default zoom.");
+
   await FullZoom.setZoom(1.25, tab1.linkedBrowser);
   tab1Zoom = ZoomManager.getZoomForBrowser(tab1.linkedBrowser);
 
@@ -46,7 +50,7 @@ add_task(async function () {
 
   is(
     tab1Zoom,
-    1.0,
+    defaultZoom,
     "privacy.resistFingerprinting is true, site-specific zoom should be reset when clearing FPP state for tab1"
   );
 
@@ -55,4 +59,20 @@ add_task(async function () {
   BrowserTestUtils.removeTab(tab1);
 
   await SpecialPowers.popPrefEnv();
+}
+
+add_task(async function () {
+  await runTest(1.0);
+
+  let defaultZoom = 1.5;
+  let context = Cu.createLoadContext();
+  let cps2 = Cc["@mozilla.org/content-pref/service;1"].getService(
+    Ci.nsIContentPrefService2
+  );
+  cps2.setGlobal(FullZoom.name, defaultZoom, context);
+  try {
+    await runTest(defaultZoom);
+  } finally {
+    cps2.removeGlobal(FullZoom.name, context);
+  }
 });
diff --git a/toolkit/components/cleardata/ClearDataService.sys.mjs b/toolkit/components/cleardata/ClearDataService.sys.mjs
@@ -438,11 +438,7 @@ const CookieBannerExecutedRecordCleaner = {
 
 // A cleaner for cleaning fingerprinting protection states.
 const FingerprintingProtectionStateCleaner = {
-  async _maybeClearSiteSpecificZoom(
-    deleteAll,
-    aSchemelessSite,
-    aOriginAttributes = {}
-  ) {
+  async _maybeClearSiteSpecificZoom(aSchemelessSite, aOriginAttributes = {}) {
     if (
       !ChromeUtils.shouldResistFingerprinting("SiteSpecificZoom", null, true)
     ) {
@@ -455,8 +451,24 @@ const FingerprintingProtectionStateCleaner = {
     const ZOOM_PREF_NAME = "browser.content.full-zoom";
 
     await new Promise((aResolve, aReject) => {
-      if (deleteAll) {
-        cps2.removeByName(ZOOM_PREF_NAME, null, {
+      aOriginAttributes =
+        ChromeUtils.fillNonDefaultOriginAttributes(aOriginAttributes);
+
+      let loadContext;
+      if (
+        aOriginAttributes.privateBrowsingId ==
+        Services.scriptSecurityManager.DEFAULT_PRIVATE_BROWSING_ID
+      ) {
+        loadContext = Cu.createLoadContext();
+      } else {
+        loadContext = Cu.createPrivateLoadContext();
+      }
+
+      cps2.removeBySubdomainAndName(
+        aSchemelessSite,
+        ZOOM_PREF_NAME,
+        loadContext,
+        {
           handleCompletion: aReason => {
             if (aReason === cps2.COMPLETE_ERROR) {
               aReject();
@@ -464,50 +476,19 @@ const FingerprintingProtectionStateCleaner = {
               aResolve();
             }
           },
-        });
-      } else {
-        aOriginAttributes =
-          ChromeUtils.fillNonDefaultOriginAttributes(aOriginAttributes);
-
-        let loadContext;
-        if (
-          aOriginAttributes.privateBrowsingId ==
-          Services.scriptSecurityManager.DEFAULT_PRIVATE_BROWSING_ID
-        ) {
-          loadContext = Cu.createLoadContext();
-        } else {
-          loadContext = Cu.createPrivateLoadContext();
         }
-
-        cps2.removeBySubdomainAndName(
-          aSchemelessSite,
-          ZOOM_PREF_NAME,
-          loadContext,
-          {
-            handleCompletion: aReason => {
-              if (aReason === cps2.COMPLETE_ERROR) {
-                aReject();
-              } else {
-                aResolve();
-              }
-            },
-          }
-        );
-      }
+      );
     });
   },
 
   async deleteAll() {
     Services.rfp.cleanAllRandomKeys();
-
-    await this._maybeClearSiteSpecificZoom(true);
   },
 
   async deleteByPrincipal(aPrincipal) {
     Services.rfp.cleanRandomKeyByPrincipal(aPrincipal);
 
     await this._maybeClearSiteSpecificZoom(
-      false,
       aPrincipal.host,
       aPrincipal.originAttributes
     );
@@ -520,7 +501,6 @@ const FingerprintingProtectionStateCleaner = {
     );
 
     await this._maybeClearSiteSpecificZoom(
-      false,
       aSchemelessSite,
       aOriginAttributesPattern
     );
@@ -532,11 +512,7 @@ const FingerprintingProtectionStateCleaner = {
       JSON.stringify(aOriginAttributesPattern)
     );
 
-    await this._maybeClearSiteSpecificZoom(
-      false,
-      aHost,
-      aOriginAttributesPattern
-    );
+    await this._maybeClearSiteSpecificZoom(aHost, aOriginAttributesPattern);
   },
 
   async deleteByOriginAttributes(aOriginAttributesString) {