Medium chrome Logic Error 📄 Reporter bug report 🔧 Commit mapped

Overview

Medium
Severity
CVSS
No
Exploited ITW
Fixed
Fix Status
ImpactInsufficient policy enforcement in Chrome for iOS
DescriptionInsufficient policy enforcement in Chrome for iOS
ComponentChrome for iOS
Bug ClassLogic Error
Tracker517184957
Fix commit0ef746da2a08 (chromium/src) +66/-4967
CISA KEVNot listed
CreditedGoogle
Disclosed2026-07-29

Changed Functions

FunctionChangeNotes
if
ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.mm
modified
TEST_F
ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
modified

Files Changed

  • ios/chrome/app/profile/profile_controller.mm
  • ios/chrome/app/strings/ios_strings.grd
  • ios/chrome/browser/browser_view/ui_bundled/BUILD.gn
  • ios/chrome/browser/location_bar/ui_bundled/DEPS
  • ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.h
  • ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.mm
  • ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
From 0ef746da2a08dea5bfe5719ad07a106e20630357 Mon Sep 17 00:00:00 2001
From: Olivier Robin <[email protected]>
Date: Thu, 11 Jun 2026 05:13:52 -0700
Subject: [PATCH] Remove RL offline pages

Offline pages is not broadly used and concentrates a high share of
security issues. Fixing them would require a full rewriting of the
feature that low usage cannot justify.

There is also a partial overlap between Reading mode and Offline pages.
As a consequence it was decided to sunset the feature.

Fixed: 522233804, 518812672, 518051499, 518089997, 517710397, 517631680, 517690521, 517184957, 514510853, 514147906, 513507830
Change-Id: Ifdbddbc1d84e43bf162e37c792e73e308895fb79
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7904425
Reviewed-by: Gauthier Ambard <[email protected]>
Commit-Queue: Olivier Robin <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1645282}
---

diff --git a/ios/chrome/app/profile/profile_controller.mm b/ios/chrome/app/profile/profile_controller.mm
index 35ce43e..eec857e 100644
--- a/ios/chrome/app/profile/profile_controller.mm
+++ b/ios/chrome/app/profile/profile_controller.mm
@@ -68,8 +68,6 @@
 #import "ios/chrome/browser/mailto_handler/model/mailto_handler_service_factory.h"
 #import "ios/chrome/browser/ntp/model/home_background_customization_promo_profile_agent.h"
 #import "ios/chrome/browser/profile_metrics/model/profile_activity_profile_agent.h"
-#import "ios/chrome/browser/reading_list/model/reading_list_download_service.h"
-#import "ios/chrome/browser/reading_list/model/reading_list_download_service_factory.h"
 #import "ios/chrome/browser/search_engines/model/extension_search_engine_data_updater.h"
 #import "ios/chrome/browser/search_engines/model/search_engines_util.h"
 #import "ios/chrome/browser/search_engines/model/template_url_service_factory.h"
@@ -125,9 +123,9 @@
 NSString* const kStartupCreateMailtoHandlerService =
     @"StartupCreateMailtoHandlerService";
 
-// Name of the block initializing the ReadingListDownloadService instance.
-NSString* const kStartupInitReadingListDownloadService =
-    @"StartupInitReadingListDownloadService";
+// Name of the block cleaning up the offline reading list directory.
+NSString* const kStartupCleanupReadingListOfflineData =
+    @"StartupCleanupReadingListOfflineData";
 
 // Name of the block that resynchronize the Spotlight index.
 NSString* const kStartResyncSpotlightIndex = @"StartResyncSpotlightIndex";
@@ -745,7 +743,7 @@
   [self scheduleClearingSessionCookies];
   [self scheduleCleanupSessionStateCache];
   [self scheduleCreateMailtoHandlerService];
-  [self scheduleInitializeReadingListDownloadService];
+  [self scheduleCleanupReadingListOfflineData];
   [self scheduleResyncSpotlightIndex];
   [self scheduleCleanupFavicons];
   [self scheduleLogStorageMetrics];
@@ -833,15 +831,15 @@
                                      }];
 }
 
-// Schedules initialization of the ReadingList download service.
-- (void)scheduleInitializeReadingListDownloadService {
+// Schedules cleanup of the ReadingList offline data directory.
+// TODO(crbug.com/522229299): Remove after Jun 2027.
+- (void)scheduleCleanupReadingListOfflineData {
   DCHECK(_state.deferredRunner);
   __weak ProfileController* weakSelf = self;
-  [_state.deferredRunner
-      enqueueBlockNamed:kStartupInitReadingListDownloadService
-                  block:^{
-                    [weakSelf initializeReadingListDownloadService];
-                  }];
+  [_state.deferredRunner enqueueBlockNamed:kStartupCleanupReadingListOfflineData
+                                     block:^{
+                                       [weakSelf cleanupReadingListOfflineData];
+                                     }];
 }
 
 // Schedules resynchronisation of the Spotlight index.
@@ -904,11 +902,18 @@
   std::ignore = MailtoHandlerServiceFactory::GetForProfile(_state.profile);
 }
 
-// Initializes the ReadingListDownloadService.
-- (void)initializeReadingListDownloadService {
+// Cleans up the ReadingList offline data directory.
+- (void)cleanupReadingListOfflineData {
   DCHECK(_state.profile);
-  ReadingListDownloadServiceFactory::GetForProfile(_state.profile)
-      ->Initialize();
+  ProfileIOS* profile = _state.profile;
+  base::FilePath offline_directory =
+      profile->GetStatePath().Append(FILE_PATH_LITERAL("Offline"));
+  base::ThreadPool::PostTask(
+      FROM_HERE,
+      {base::MayBlock(), base::TaskPriority::BEST_EFFORT,
+       base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN},
+      base::BindOnce(base::IgnoreResult(&base::DeletePathRecursively),
+                     offline_directory));
 }
 
 // Resynchronizes the spotlight index.
diff --git a/ios/chrome/app/strings/ios_strings.grd b/ios/chrome/app/strings/ios_strings.grd
index 555038eb..2b7086b 100644
--- a/ios/chrome/app/strings/ios_strings.grd
+++ b/ios/chrome/app/strings/ios_strings.grd
@@ -5255,12 +5255,6 @@
       <message name="IDS_IOS_PAGE_INFO_CONNECTION" desc="Title of the button opening the connection information (in page info)">
         Connection
       </message>
-      <message name="IDS_IOS_PAGE_INFO_OFFLINE_PAGE" desc="Message to display in the page info when the page you are on is an offline page.">
-        This page has been saved to your Reading List.
-      </message>
-      <message name="IDS_IOS_PAGE_INFO_OFFLINE_PAGE_LABEL" desc="Label to display at the top of the site information screen when the page you are on is an offline page.">
-        Offline page
-      </message>
       <message name="IDS_IOS_PAGE_INFO_OFFLINE_TITLE" desc="Title of the message to display in the page info bubble when the page you are on is an offline page.">
         Viewing offline version
       </message>
diff --git a/ios/chrome/browser/browser_view/ui_bundled/BUILD.gn b/ios/chrome/browser/browser_view/ui_bundled/BUILD.gn
index bed08863..6a446735 100644
--- a/ios/chrome/browser/browser_view/ui_bundled/BUILD.gn
+++ b/ios/chrome/browser/browser_view/ui_bundled/BUILD.gn
@@ -438,6 +438,7 @@
     "//ios/chrome/browser/commerce/model:shopping_service",
     "//ios/chrome/browser/content_settings/model",
     "//ios/chrome/browser/discover_feed/model:discover_feed_visibility_browser_agent",
+    "//ios/chrome/browser/dom_distiller/model",
     "//ios/chrome/browser/download/model",
     "//ios/chrome/browser/download/ui",
     "//ios/chrome/browser/favicon/model",
diff --git a/ios/chrome/browser/location_bar/ui_bundled/DEPS b/ios/chrome/browser/location_bar/ui_bundled/DEPS
index 0fba61e3..feab4cc2 100644
--- a/ios/chrome/browser/location_bar/ui_bundled/DEPS
+++ b/ios/chrome/browser/location_bar/ui_bundled/DEPS
@@ -41,7 +41,6 @@
   "+ios/chrome/browser/reader_mode/model/features.h",
   "+ios/chrome/browser/reader_mode/model/reader_mode_web_state_utils.h",
   "+ios/chrome/browser/reader_mode/ui/reader_mode_chip_visibility_delegate.h",
-  "+ios/chrome/browser/reading_list/model/offline_page_tab_helper.h",
   "+ios/chrome/browser/search_engines/model",
   "+ios/chrome/browser/sharing/ui_bundled",
   "+ios/chrome/browser/sync/model/send_tab_to_self_sync_service_factory.h",
diff --git a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.h b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.h
index 22a51e0..7ef7eb4 100644
--- a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.h
+++ b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.h
@@ -52,7 +52,6 @@
   GetVisibleSecurityState() const override;
   scoped_refptr<net::X509Certificate> GetCertificate() const override;
   const gfx::VectorIcon* GetVectorIconOverride() const override;
-  bool IsOfflinePage() const override;
   bool IsNewTabPage() const override;
   bool IsNewTabPageURL(const GURL& url) const override;
   bool IsHomePage(const GURL& url) const override;
diff --git a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.mm b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.mm
index 13b1e04..72c8232a 100644
--- a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.mm
+++ b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios.mm
@@ -13,7 +13,6 @@
 #import "components/prefs/pref_service.h"
 #import "components/security_state/ios/security_state_utils.h"
 #import "ios/chrome/browser/autocomplete/model/autocomplete_scheme_classifier_impl.h"
-#import "ios/chrome/browser/reading_list/model/offline_page_tab_helper.h"
 #import "ios/chrome/browser/search_engines/model/template_url_service_factory.h"
 #import "ios/chrome/browser/shared/model/prefs/pref_names.h"
 #import "ios/chrome/browser/shared/model/profile/profile_ios.h"
@@ -120,15 +119,6 @@
   return nullptr;
 }
 
-bool LocationBarModelDelegateIOS::IsOfflinePage() const {
-  web::WebState* web_state = GetActiveWebState();
-  if (!web_state) {
-    return false;
-  }
-  OfflinePageTabHelper* helper = OfflinePageTabHelper::FromWebState(web_state);
-  return helper && helper->presenting_offline_page();
-}
-
 bool LocationBarModelDelegateIOS::IsNewTabPage() const {
   // This is currently only called by the OmniboxEditModel to determine if the
   // Google landing page is showing.
diff --git a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
index ed2b9c9..e4ec8149 100644
--- a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
+++ b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
@@ -37,19 +37,7 @@
   std::unique_ptr<LocationBarModelDelegateIOS> delegate_;
 };
 
-// Tests that IsOfflinePage() returns false if there is no WebState.
-TEST_F(LocationBarModelDelegateIOSTest, IsOfflinePage_NoWebState) {
-  provider_.webState = nullptr;
-  EXPECT_FALSE(delegate_->IsOfflinePage());
-}
-
-// Tests that IsOfflinePage() returns false if the WebState has no
-// OfflinePageTabHelper attached (to verify defensive null check for
-// b/505753157).
-TEST_F(LocationBarModelDelegateIOSTest, IsOfflinePage_NoHelper) {
Loading diff…

Regression Test / PoC

shipped with the fix
diff --git a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
index ed2b9c9..e4ec8149 100644
--- a/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
+++ b/ios/chrome/browser/location_bar/ui_bundled/location_bar_model_delegate_ios_unittest.mm
@@ -37,19 +37,7 @@
   std::unique_ptr<LocationBarModelDelegateIOS> delegate_;
 };
 
-// Tests that IsOfflinePage() returns false if there is no WebState.
-TEST_F(LocationBarModelDelegateIOSTest, IsOfflinePage_NoWebState) {
-  provider_.webState = nullptr;
-  EXPECT_FALSE(delegate_->IsOfflinePage());
-}
-
-// Tests that IsOfflinePage() returns false if the WebState has no
-// OfflinePageTabHelper attached (to verify defensive null check for
-// b/505753157).
-TEST_F(LocationBarModelDelegateIOSTest, IsOfflinePage_NoHelper) {
-  web::FakeWebState web_state;
-  provider_.webState = &web_state;
-  // Without OfflinePageTabHelper attached, this should return false and not
-  // crash.
+// Tests that IsOfflinePage() returns false.
+TEST_F(LocationBarModelDelegateIOSTest, IsOfflinePage) {
   EXPECT_FALSE(delegate_->IsOfflinePage());
 }
diff --git a/ios/chrome/browser/reading_list/model/offline_page_tab_helper_unittest.mm b/ios/chrome/browser/reading_list/model/offline_page_tab_helper_unittest.mm
deleted file mode 100644
index e7287a8..0000000
--- a/ios/chrome/browser/reading_list/model/offline_page_tab_helper_unittest.mm
+++ /dev/null
@@ -1,286 +0,0 @@
-// Copyright 2019 The Chromium Authors
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#import "ios/chrome/browser/reading_list/model/offline_page_tab_helper.h"
-
-#import <memory>
-#import <vector>
-
-#import "base/memory/scoped_refptr.h"
-#import "base/run_loop.h"
-#import "base/test/ios/wait_util.h"
-#import "base/time/default_clock.h"
-#import "components/reading_list/core/fake_reading_list_model_storage.h"
-#import "components/reading_list/core/reading_list_entry.h"
-#import "components/reading_list/core/reading_list_model_impl.h"
-#import "components/sync/base/storage_type.h"
-#import "components/sync/model/wipe_model_upon_sync_disabled_behavior.h"
-#import "ios/chrome/browser/reading_list/model/reading_list_model_factory.h"
-#import "ios/chrome/browser/reading_list/model/reading_list_test_utils.h"
-#import "ios/chrome/browser/shared/model/profile/test/test_profile_ios.h"
-#import "ios/web/public/test/fakes/fake_navigation_context.h"
-#import "ios/web/public/test/fakes/fake_navigation_manager.h"
-#import "ios/web/public/test/fakes/fake_web_state.h"
-#import "ios/web/public/test/web_task_environment.h"
-#import "testing/gtest/include/gtest/gtest.h"
-#import "testing/platform_test.h"
-
-namespace {
-const char kTestURL[] = "http://foo.test";
-const char kTestSecondURL[] = "http://bar.test";
-const char kTestTitle[] = "title";
-const char kTestDistilledPath[] = "distilled.html";
-const char kTestDistilledURL[] = "http://foo.bar/distilled";
-}  // namespace
-
-// Test fixture to test loading of Reading list offline pages.
-class OfflinePageTabHelperTest : public PlatformTest {
- public:
-  void SetUp() override {
-    PlatformTest::SetUp();
-
-    std::vector<scoped_refptr<ReadingListEntry>> initial_entries;
-    initial_entries.push_back(base::MakeRefCounted<ReadingListEntry>(
-        GURL(kTestURL), kTestTitle, base::Time::Now()));
-
-    TestProfileIOS::Builder builder;
-    builder.AddTestingFactory(ReadingListModelFactory::GetInstance(),
-                              ReadingListModelTestingFactoryWithFakeStorage(
-                                  std::move(initial_entries)));
-    profile_ = std::move(builder).Build();
-
-    fake_web_state_.SetBrowserState(profile_.get());
-    fake_web_state_.SetNavigationManager(
-        std::make_unique<web::FakeNavigationManager>());
-
-    OfflinePageTabHelper::CreateForWebState(&fake_web_state_,
-                                            reading_list_model());
-  }
-
-  ReadingListModel* reading_list_model() {
-    return ReadingListModelFactory::GetForProfile(profile_.get());
-  }
-
- protected:
-  web::WebTaskEnvironment task_environment_;
-  std::unique_ptr<TestProfileIOS> profile_;
-  web::FakeWebState fake_web_state_;
-};
-
-// Test fixture to test loading of Reading list offline pages with a delayed
-// ReadingListModel.
-class OfflinePageTabHelperDelayedModelTest : public PlatformTest {
- public:
-  void SetUp() override {
-    PlatformTest::SetUp();
-
-    auto storage = std::make_unique<FakeReadingListModelStorage>();
-    fake_reading_list_model_storage_ = storage->AsWeakPtr();
-
-    TestProfileIOS::Builder builder;
-    builder.AddTestingFactory(
-        ReadingListModelFactory::GetInstance(),
-        base::BindRepeating(
-            [](std::unique_ptr<FakeReadingListModelStorage>& storage,
-               ProfileIOS* profile) -> std::unique_ptr<KeyedService> {
-              DCHECK(storage.get());
-              return std::make_unique<ReadingListModelImpl>(
-                  std::move(storage), syncer::StorageType::kUnspecified,
-                  syncer::WipeModelUponSyncDisabledBehavior::kNever,
-                  base::DefaultClock::GetInstance());
-            },
-            base::OwnedRef(std::move(storage))));
-    profile_ = std::move(builder).Build();
-
-    fake_web_state_.SetBrowserState(profile_.get());
-    fake_web_state_.SetNavigationManager(
-        std::make_unique<web::FakeNavigationManager>());
-
-    OfflinePageTabHelper::CreateForWebState(&fake_web_state_,
-                                            reading_list_model());
-  }
-
-  ReadingListModel* reading_list_model() {
-    return ReadingListModelFactory::GetForProfile(profile_.get());
-  }
-
-  FakeReadingListModelStorage* fake_reading_list_model_storage() {
-    return fake_reading_list_model_storage_.get();
-  }
-
- protected:
-  web::WebTaskEnvironment task_environment_;
-  std::unique_ptr<TestProfileIOS> profile_;
-  web::FakeWebState fake_web_state_;
-  base::WeakPtr<FakeReadingListModelStorage> fake_reading_list_model_storage_;
-};
-
-// Tests that loading an online version does mark it read.
-TEST_F(OfflinePageTabHelperTest, TestLoadReadingListSuccess) {
-  GURL url(kTestURL);
-  scoped_refptr<const ReadingListEntry> entry =
-      reading_list_model()->GetEntryByURL(url);
-  fake_web_state_.SetCurrentURL(url);
-  web::FakeNavigationContext context;
-  context.SetUrl(url);
-  context.SetHasCommitted(true);
-  fake_web_state_.OnNavigationStarted(&context);
-  fake_web_state_.OnNavigationFinished(&context);
-  fake_web_state_.OnPageLoaded(web::PageLoadCompletionStatus::SUCCESS);
-  EXPECT_FALSE(base::test::ios::WaitUntilConditionOrTimeout(
-      base::test::ios::kWaitForFileOperationTimeout, ^bool {
-        base::RunLoop().RunUntilIdle();
-        return fake_web_state_.GetLastLoadedData();
-      }));
-  EXPECT_FALSE(fake_web_state_.GetLastLoadedData());
-  EXPECT_TRUE(entry->IsRead());
-  EXPECT_FALSE(OfflinePageTabHelper::FromWebState(&fake_web_state_)
-                   ->presenting_offline_page());
-}
-
-// Tests that failing loading an online version does not mark it read.
-TEST_F(OfflinePageTabHelperTest, TestLoadReadingListFailure) {
-  GURL url(kTestURL);
-  scoped_refptr<const ReadingListEntry> entry =
-      reading_list_model()->GetEntryByURL(url);
-  web::FakeNavigationContext context;
-  context.SetUrl(url);
-  context.SetHasCommitted(true);
-  fake_web_state_.OnNavigationStarted(&context);
-  fake_web_state_.OnNavigationFinished(&context);
-  fake_web_state_.OnPageLoaded(web::PageLoadCompletionStatus::FAILURE);
-  EXPECT_FALSE(base::test::ios::WaitUntilConditionOrTimeout(
-      base::test::ios::kWaitForFileOperationTimeout, ^bool {
-        base::RunLoop().RunUntilIdle();
-        return fake_web_state_.GetLastLoadedData();
-      }));
-  EXPECT_FALSE(fake_web_state_.GetLastLoadedData());
-  EXPECT_FALSE(entry->IsRead());
-  EXPECT_FALSE(OfflinePageTabHelper::FromWebState(&fake_web_state_)
-                   ->presenting_offline_page());
-}
-
-// Tests that failing loading an online version will load the distilled version
-// and mark it read.
-TEST_F(OfflinePageTabHelperTest, TestLoadReadingListDistilled) {
-  GURL url(kTestURL);
-  std::string distilled_path = kTestDistilledPath;
-  reading_list_model()->SetEntryDistilledInfoIfExists(
-      url, base::FilePath(distilled_path), GURL(kTestDistilledURL), 50,
-      base::Time::FromTimeT(100));
-  scoped_refptr<const ReadingListEntry> entry =
-      reading_list_model()->GetEntryByURL(url);
-  fake_web_state_.SetCurrentURL(url);
-  web::FakeNavigationContext context;
-  context.SetHasCommitted(true);
-  std::unique_ptr<web::NavigationItem> item = web::NavigationItem::Create();
-  static_cast<web::FakeNavigationManager*>(
-      fake_web_state_.GetNavigationManager())
-      ->SetLastCommittedItem(item.get());
-  context.SetUrl(url);
-  fake_web_state_.OnNavigationStarted(&context);
-  fake_web_state_.OnNavigationFinished(&context);
-  fake_web_state_.OnPageLoaded(web::PageLoadCompletionStatus::FAILURE);
-  EXPECT_FALSE(fake_web_state_.GetLastLoadedData());
-  EXPECT_FALSE(entry->IsRead());
-  EXPECT_TRUE(base::test::ios::WaitUntilConditionOrTimeout(
-      base::test::ios::kWaitForFileOperationTimeout, ^bool {
-        base::RunLoop().RunUntilIdle();
-        return fake_web_state_.GetLastLoadedData();
-      }));
-  EXPECT_TRUE(entry->IsRead());
-  EXPECT_TRUE(OfflinePageTabHelper::FromWebState(&fake_web_state_)
-                  ->presenting_offline_page());
-}
-
-// Tests that failing loading an online version does not load distilled
-// version if another navigation started.
-TEST_F(OfflinePageTabHelperTest, TestLoadReadingListFailureThenNavigate) {
-  GURL url(kTestURL);
-  GURL second_url(kTestSecondURL);
-  scoped_refptr<const ReadingListEntry> entry =
-      reading_list_model()->GetEntryByURL(url);
-  web::FakeNavigationContext context;
-  context.SetHasCommitted(true);
-  context.SetUrl(url);
-  fake_web_state_.OnNavigationStarted(&context);
-  fake_web_state_.OnNavigationFinished(&context);
-  fake_web_state_.OnPageLoaded(web::PageLoadCompletionStatus::FAILURE);
-
-  web::FakeNavigationContext second_context;
-  second_context.SetUrl(second_url);
-  second_context.SetHasCommitted(true);
-  fake_web_state_.OnNavigationStarted(&second_context);
-  EXPECT_FALSE(base::test::ios::WaitUntilConditionOrTimeout(
-      base::test::ios::kWaitForFileOperationTimeout, ^bool {
-        base::RunLoop().RunUntilIdle();
-        return fake_web_state_.GetLastLoadedData();
-      }));
-  EXPECT_FALSE(fake_web_state_.GetLastLoadedData());
-  EXPECT_FALSE(entry->IsRead());
-  EXPECT_FALSE(OfflinePageTabHelper::FromWebState(&fake_web_state_)
-                   ->presenting_offline_page());
-}
-
-// Tests that OfflinePageTabHelper correctly reports existence of a distilled
-// version.
-TEST_F(OfflinePageTabHelperTest, TestHasDistilledVersionForOnlineUrl) {
-  OfflinePageTabHelper* offline_page_tab_helper =
-      OfflinePageTabHelper::FromWebState(&fake_web_state_);
-  GURL url(kTestURL);
-  EXPECT_FALSE(offline_page_tab_helper->HasDistilledVersionForOnlineUrl(url));
-  GURL second_url(kTestSecondURL);
-  EXPECT_FALSE(
-      offline_page_tab_helper->HasDistilledVersionForOnlineUrl(second_url));
-
-  std::string distilled_path = kTestDistilledPath;
-  reading_list_model()->SetEntryDistilledInfoIfExists(
-      url, base::FilePath(distilled_path), GURL(kTestDistilledURL), 50,
-      base::Time::FromTimeT(100));
-  EXPECT_TRUE(offline_page_tab_helper->HasDistilledVersionForOnlineUrl(url));
-}
-
-// Tests that OfflinePageTabHelper correctly shows Offline page if model takes
-// a long time to load.
-TEST_F(OfflinePageTabHelperDelayedModelTest, TestLateReadingListModelLoading) {
-  OfflinePageTabHelper* offline_page_tab_helper =
-      OfflinePageTabHelper::FromWebState(&fake_web_state_);
-  GURL url(kTestURL);
-  EXPECT_FALSE(offline_page_tab_helper->HasDistilledVersionForOnlineUrl(url));
-  web::FakeNavigationContext context;
-
-  context.SetHasCommitted(true);
-  std::unique_ptr<web::NavigationItem> item = web::NavigationItem::Create();
-  static_cast<web::FakeNavigationManager*>(
-      fake_web_state_.GetNavigationManager())
-      ->SetLastCommittedItem(item.get());
-  context.SetUrl(url);
-  fake_web_state_.OnNavigationStarted(&context);
-  fake_web_state_.OnNavigationFinished(&context);
-  fake_web_state_.OnPageLoaded(web::PageLoadCompletionStatus::FAILURE);
-  EXPECT_FALSE(base::test::ios::WaitUntilConditionOrTimeout(
-      base::test::ios::kWaitForFileOperationTimeout, ^bool {
-        base::RunLoop().RunUntilIdle();
-        return fake_web_state_.GetLastLoadedData();
-      }));
-  EXPECT_FALSE(offline_page_tab_helper->presenting_offline_page());
-  // Complete the reading list model load from storage.
... (truncated)
Loading diff…

Original Bug Report

reported by [email protected]

Potential security policy and permission bypass in iOS Reading List background distillation

Project Fortify, an experimental security project, has identified the following potential security issue. If you’re a feature owner CC-ed on this bug, please do your best to review these reports. Please see https://chromium.googlesource.com/chromium/src/+/main/docs/security/ai-generated-security-bugs-faq.md for more information.

Overview: The iOS Reading List background distillation pipeline creates a profile-backed WebState without standard tab helpers or a WebState delegate. Consequently, navigations to added URLs bypass enterprise URL blocklists, Safe Browsing, and parental control filters (Family Link). In addition, requests for media permissions fall back to triggering a native iOS prompt rather than consulting parental media restriction policies.

Affected files:

  • ios/chrome/browser/reading_list/model/favicon_web_state_dispatcher_impl.mm
  • components/dom_distiller/ios/distiller_page_ios.mm
  • ios/chrome/browser/reading_list/model/reading_list_distiller_page.mm

Estimated timestamp from git blame: 2016-12-21

Root Cause Analysis

The background distillation pipeline for the iOS Reading List creates a profile-backed web::WebState but does not attach standard tab helpers or set a delegate on it. This causes several security features and parental control policies to be bypassed during background distillation:

  1. Omission of Tab Helpers (Policy Bypass): In FaviconWebStateDispatcherImpl::RequestWebState() (located in ios/chrome/browser/reading_list/model/favicon_web_state_dispatcher_impl.mm), a new profile-backed web::WebState is created, but AttachTabHelpers() is never called on it. Consequently, security policy deciders (which register as web::WebStatePolicyDeciders during tab helper attachment) are entirely missing from this WebState. This includes:

    • SupervisedUserURLFilterTabHelper (enforces Family Link parental URL blocks)
    • SafeBrowsingTabHelper (enforces Safe Browsing blocks)
    • PolicyUrlBlockingTabHelper (enforces Enterprise URL blocklists)

    Because these policy deciders are absent, any background navigation initiated by the distiller page to an added URL proceeds completely unrestricted, executing JavaScript under the attacker’s origin with the victim’s active profile cookies.

  2. Omission of WebStateDelegate (Permission Bypass): No web::WebStateDelegate is set on this background WebState. In WebStateImpl::RealizedWebState::RequestPermissionsWithDecisionHandler (located in ios/web/web_state/web_state_impl_realized_web_state.mm), when a page requests camera or microphone access, the code checks if a delegate is present. Since delegate_ is null, it falls through to the else block:

    } else {
      web_view_decision_handler(WKPermissionDecisionPrompt);
    }
    

    This bypasses the standard parental permission verification (which is normally delegated to browser-level agents) and directly prompts the user with the native iOS permission dialog.

Suggested / Potential Attack Scenario

Note: These are potential steps; our tooling does not currently have the capability to run code to confirm the exploit.

  1. A supervised user (subject to URL restrictions or camera/mic blocks) visits a permitted page containing a link to a blocked URL (e.g., https://attacker.example).
  2. The user long-presses the link and selects Add to Reading List, which triggers background distillation via ReadingListDownloadService.
  3. The background service requests a new WebState from FaviconWebStateDispatcherImpl and navigates to the URL within a hidden WindowedContainerView in the background.
  4. Because SupervisedUserURLFilterTabHelper and other security deciders are missing, the restricted page successfully loads and executes JavaScript in the background with the user’s cookies.
  5. If the malicious page requests microphone or camera access via navigator.mediaDevices.getUserMedia(), the system bypasses parental restrictions and triggers a native iOS permission prompt directly to the user.

Suggested Fix

To resolve this issue, the background WebState used for distillation should be properly secured:

  1. Invoke AttachTabHelpers() with an appropriate tab helper filter (or define a new specific filter for background distillation) to ensure that security deciders (SupervisedUserURLFilterTabHelper, SafeBrowsingTabHelper, PolicyUrlBlockingTabHelper) are active.
  2. Ensure that a proper web::WebStateDelegate is assigned to the distillation WebState to correctly handle and reject permission requests (camera, microphone, etc.) under restricted profiles rather than falling back to native iOS prompt decisions.

Evaluated with Chrome root at commit: b1520ef4a76878853a31f0943b565e42060edec8


Results so far have been promising, but there can be wrong deductions. Feel free to adjust as follows:

  • If you are familiar with the severity guidelines, you may adjust the severity.
  • If this is a false positive, and there’s no work to be done, please close as WAI.
  • If there is work to do here but not a vulnerability, please change the issue type to Task/Bug/FR.

Data from false positives will be used to improve accuracy over time. And please feel free to reach out to me directly if you have concerns or feedback on the project.

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