From c3c4adcd645122ce624b588e5f3609ae77b93f12 Mon Sep 17 00:00:00 2001
From: Keita Suzuki <suzukikeita@chromium.org>
Date: Sun, 05 Jul 2026 22:48:42 -0700
Subject: [PATCH] Preserve initiator origin for intercepted same-document commits

When a same-document fragment navigation is intercepted via
NavigateEvent.intercept(), the resulting commit goes through
RunURLAndHistoryUpdateSteps() which previously always used the target
frame's own origin as the initiator. Thread the original initiator
origin from CommitSameDocumentNavigation() through
NavigateEventDispatchParams so that the intercepted commit reflects who
actually started the navigation.

Also extend the same-document text-fragment token regeneration to cover
kNavigationApiIntercept and teach GenerateNewTokenForSameDocument() to
treat that type the same as a fragment navigation, so an intercepted
navigation computes the same text-fragment token state as the equivalent
un-intercepted one would.

Add a content browsertest covering a cross-origin iframe that calls
window.top.location.replace() with a text directive while the top frame
intercepts the navigation.

TAG=agy
CONV=13ec7a8f-4d73-4c01-b1b7-4d465e984eb3

Bug: 513841856
Change-Id: I007fe1a7ac7132bd6b76348fe870ea416d33c238
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8017843
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Commit-Queue: Keita Suzuki <suzukikeita@chromium.org>
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1656984}
---

diff --git a/content/browser/text_fragment_browsertest.cc b/content/browser/text_fragment_browsertest.cc
index c5f91f11..066e390 100644
--- a/content/browser/text_fragment_browsertest.cc
+++ b/content/browser/text_fragment_browsertest.cc
@@ -640,6 +640,82 @@
   }
 }
 
+// Ensure same-document navigation to a text-fragment is blocked when initiated
+// from a different origin and the destination intercepts the navigation via the
+// navigation API.
+IN_PROC_BROWSER_TEST_F(
+    TextFragmentAnchorBrowserTest,
+    SameDocumentScriptNavigationCrossOriginWithNavigationIntercept) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+  GURL url(embedded_test_server()->GetURL(
+      "a.test", "/scrollable_page_with_content.html"));
+  GURL target_text_url(embedded_test_server()->GetURL(
+      "a.test", "/scrollable_page_with_content.html#:~:text=hidden"));
+  GURL cross_origin_inner_url(
+      embedded_test_server()->GetURL("b.test", "/hello.html"));
+
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  WebContentsImpl* main_contents =
+      static_cast<WebContentsImpl*>(shell()->web_contents());
+  FrameTreeNode* root = main_contents->GetPrimaryFrameTree().root();
+
+  // Register a navigate handler that intercepts the same-document navigation
+  // and add a hidden=until-found target so we can detect whether the text
+  // directive was processed via the beforematch event.
+  EXPECT_TRUE(ExecJs(main_contents,
+                     R"JS(
+        let target = document.createElement('div');
+        target.hidden = 'until-found';
+        target.textContent = 'hidden text';
+        document.body.appendChild(target);
+        var did_match = false;
+        target.addEventListener('beforematch', () => { did_match = true; });
+        navigation.addEventListener('navigate', e => {
+          if (e.canIntercept) {
+            e.intercept({handler: async () => {}});
+          }
+        });
+      )JS",
+                     EXECUTE_SCRIPT_NO_USER_GESTURE));
+
+  // Insert a cross-origin iframe from which we'll execute script.
+  {
+    const auto script = JsReplace(
+        R"JS(
+            let f = document.createElement("iframe");
+            f.src=$1;
+            document.body.appendChild(f);
+          )JS",
+        cross_origin_inner_url);
+
+    TestNavigationObserver observer(main_contents);
+    EXPECT_TRUE(ExecJs(main_contents, script, EXECUTE_SCRIPT_NO_USER_GESTURE));
+    observer.Wait();
+    ASSERT_EQ(1u, root->child_count());
+  }
+
+  // Try navigating the top frame to a same-document text fragment from inside
+  // the iframe via location.replace(). The destination page intercepts the
+  // navigation, but the text directive should still be blocked because the
+  // initiator is cross-origin.
+  {
+    TestNavigationObserver observer(main_contents);
+    RenderFrameHostImpl* child_rfh = root->child_at(0)->current_frame_host();
+    EXPECT_TRUE(ExecJs(child_rfh, JsReplace("window.top.location.replace($1);",
+                                            target_text_url)));
+    observer.Wait();
+    EXPECT_EQ(target_text_url, main_contents->GetLastCommittedURL());
+
+    WaitForPageLoad(main_contents);
+    RunUntilInputProcessed(GetWidgetHost());
+    RunUntilInputProcessed(GetWidgetHost());
+    EXPECT_EQ(false, EvalJs(main_contents, "did_match;",
+                            EXECUTE_SCRIPT_NO_USER_GESTURE));
+    EXPECT_DID_SCROLL(false);
+  }
+}
+
 // Test that when ForceLoadAtTop document policy is explicitly turned off,
 // scrolling to a text fragment is allowed.
 IN_PROC_BROWSER_TEST_F(TextFragmentAnchorBrowserTest, EnabledByDocumentPolicy) {
diff --git a/third_party/blink/renderer/core/fragment_directive/text_fragment_anchor.cc b/third_party/blink/renderer/core/fragment_directive/text_fragment_anchor.cc
index 0d8f696..0fb4b09d 100644
--- a/third_party/blink/renderer/core/fragment_directive/text_fragment_anchor.cc
+++ b/third_party/blink/renderer/core/fragment_directive/text_fragment_anchor.cc
@@ -141,9 +141,12 @@
     mojom::blink::SameDocumentNavigationType same_document_navigation_type) {
   if ((load_type != WebFrameLoadType::kStandard &&
        load_type != WebFrameLoadType::kReplaceCurrentItem) ||
-      same_document_navigation_type !=
-          mojom::blink::SameDocumentNavigationType::kFragment)
+      (same_document_navigation_type !=
+           mojom::blink::SameDocumentNavigationType::kFragment &&
+       same_document_navigation_type !=
+           mojom::blink::SameDocumentNavigationType::kNavigationApiIntercept)) {
     return false;
+  }
 
   // Same-document text fragment navigations are allowed only when initiated
   // from the browser process (e.g. typing in the omnibox) or a same-origin
diff --git a/third_party/blink/renderer/core/loader/document_loader.cc b/third_party/blink/renderer/core/loader/document_loader.cc
index 77bd92d..56f7d56 100644
--- a/third_party/blink/renderer/core/loader/document_loader.cc
+++ b/third_party/blink/renderer/core/loader/document_loader.cc
@@ -1028,15 +1028,20 @@
     UserNavigationInvolvement involvement,
     PerformanceTimelineEntryIdInfo interaction_id,
     bool is_browser_initiated,
-    bool is_synchronously_committed) {
-  // We use the security origin of this frame since callers of this method must
-  // already have performed same origin checks.
+    bool is_synchronously_committed,
+    const SecurityOrigin* initiator_origin) {
+  // Unless the caller has explicitly provided an initiator (e.g. when
+  // committing an intercepted navigate event that was started by a different
+  // frame), use the security origin of this frame since callers of this
+  // method must already have performed same origin checks.
   // is_browser_initiated is false and is_synchronously_committed is true
   // because anything invoking this algorithm is a renderer-initiated navigation
   // in this process.
   UpdateForSameDocumentNavigation(
       new_url, history_item, same_document_navigation_type, std::move(data),
-      type, fire_popstate, frame_->DomWindow()->GetSecurityOrigin(),
+      type, fire_popstate,
+      initiator_origin ? initiator_origin
+                       : frame_->DomWindow()->GetSecurityOrigin(),
       is_browser_initiated, is_synchronously_committed,
       LocalFrame::HasTransientUserActivation(frame_), involvement,
       /*has_ua_visual_transition*/ false, should_skip_screenshot,
@@ -1102,7 +1107,12 @@
     http_method_ = http_names::kGET;
     http_body_ = nullptr;
   }
-
+  // Same-document text fragment navigations are restricted to same-origin or
+  // browser-initiated navigations for security. We must use the original
+  // initiator origin (which might be passed from an intercepted navigate event)
+  // rather than the target frame's origin.
+  // See
+  // https://wicg.github.io/scroll-to-text-fragment/#restricting-the-text-fragment
   last_navigation_had_trusted_initiator_ =
       !initiator_origin || (initiator_origin->IsSameOriginWith(
                                 frame_->DomWindow()->GetSecurityOrigin()) &&
@@ -1117,7 +1127,9 @@
   // history API.
   if (type == WebFrameLoadType::kStandard ||
       same_document_navigation_type ==
-          mojom::blink::SameDocumentNavigationType::kFragment) {
+          mojom::blink::SameDocumentNavigationType::kFragment ||
+      same_document_navigation_type ==
+          mojom::blink::SameDocumentNavigationType::kNavigationApiIntercept) {
     has_text_fragment_token_ =
         TextFragmentAnchor::GenerateNewTokenForSameDocument(
             *this, type, same_document_navigation_type);
@@ -1779,6 +1791,7 @@
     params->involvement = involvement;
     params->source_element = source_element;
     params->destination_item = history_item;
+    params->initiator_origin = initiator_origin;

diff --git a/content/browser/text_fragment_browsertest.cc b/content/browser/text_fragment_browsertest.cc
index c5f91f11..066e390 100644
--- a/content/browser/text_fragment_browsertest.cc
+++ b/content/browser/text_fragment_browsertest.cc
@@ -640,6 +640,82 @@
   }
 }
 
+// Ensure same-document navigation to a text-fragment is blocked when initiated
+// from a different origin and the destination intercepts the navigation via the
+// navigation API.
+IN_PROC_BROWSER_TEST_F(
+    TextFragmentAnchorBrowserTest,
+    SameDocumentScriptNavigationCrossOriginWithNavigationIntercept) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+  GURL url(embedded_test_server()->GetURL(
+      "a.test", "/scrollable_page_with_content.html"));
+  GURL target_text_url(embedded_test_server()->GetURL(
+      "a.test", "/scrollable_page_with_content.html#:~:text=hidden"));
+  GURL cross_origin_inner_url(
+      embedded_test_server()->GetURL("b.test", "/hello.html"));
+
+  EXPECT_TRUE(NavigateToURL(shell(), url));
+
+  WebContentsImpl* main_contents =
+      static_cast<WebContentsImpl*>(shell()->web_contents());
+  FrameTreeNode* root = main_contents->GetPrimaryFrameTree().root();
+
+  // Register a navigate handler that intercepts the same-document navigation
+  // and add a hidden=until-found target so we can detect whether the text
+  // directive was processed via the beforematch event.
+  EXPECT_TRUE(ExecJs(main_contents,
+                     R"JS(
+        let target = document.createElement('div');
+        target.hidden = 'until-found';
+        target.textContent = 'hidden text';
+        document.body.appendChild(target);
+        var did_match = false;
+        target.addEventListener('beforematch', () => { did_match = true; });
+        navigation.addEventListener('navigate', e => {
+          if (e.canIntercept) {
+            e.intercept({handler: async () => {}});
+          }
+        });
+      )JS",
+                     EXECUTE_SCRIPT_NO_USER_GESTURE));
+
+  // Insert a cross-origin iframe from which we'll execute script.
+  {
+    const auto script = JsReplace(
+        R"JS(
+            let f = document.createElement("iframe");
+            f.src=$1;
+            document.body.appendChild(f);
+          )JS",
+        cross_origin_inner_url);
+
+    TestNavigationObserver observer(main_contents);
+    EXPECT_TRUE(ExecJs(main_contents, script, EXECUTE_SCRIPT_NO_USER_GESTURE));
+    observer.Wait();
+    ASSERT_EQ(1u, root->child_count());
+  }
+
+  // Try navigating the top frame to a same-document text fragment from inside
+  // the iframe via location.replace(). The destination page intercepts the
+  // navigation, but the text directive should still be blocked because the
+  // initiator is cross-origin.
+  {
+    TestNavigationObserver observer(main_contents);
+    RenderFrameHostImpl* child_rfh = root->child_at(0)->current_frame_host();
+    EXPECT_TRUE(ExecJs(child_rfh, JsReplace("window.top.location.replace($1);",
+                                            target_text_url)));
+    observer.Wait();
+    EXPECT_EQ(target_text_url, main_contents->GetLastCommittedURL());
+
+    WaitForPageLoad(main_contents);
+    RunUntilInputProcessed(GetWidgetHost());
+    RunUntilInputProcessed(GetWidgetHost());
+    EXPECT_EQ(false, EvalJs(main_contents, "did_match;",
+                            EXECUTE_SCRIPT_NO_USER_GESTURE));
+    EXPECT_DID_SCROLL(false);
+  }
+}
+
 // Test that when ForceLoadAtTop document policy is explicitly turned off,
 // scrolling to a text fragment is allowed.
 IN_PROC_BROWSER_TEST_F(TextFragmentAnchorBrowserTest, EnabledByDocumentPolicy) {