From 4ae79680fd4013a566bbcd140ed53bffbe76eee9 Mon Sep 17 00:00:00 2001
From: Tzarial <zork@google.com>
Date: Thu, 25 Jun 2026 05:36:33 -0700
Subject: [PATCH] [agy][content] Block PDF NotificationService

PDF renderers are isolated and must not access storage, passwords,
or other sensitive data for the PDF document's origin. However, the
eager/lazy interface binding path for blink.mojom.NotificationService
on RenderFrameHostImpl was not gated by any PDF check. This allowed a
compromised PDF renderer to bind the service and read or spoof
notifications.

This CL prevents PDF renderers from binding the NotificationService
on the BrowserInterfaceBroker path. If a PDF renderer attempts to bind
it, the browser now terminates the renderer using
mojo::ReportBadMessage.

We verify this fix with a new unit test in
render_frame_host_impl_unittest.cc.

Test: content_unittests --gtest_filter=RenderFrameHostImplTest.NotificationServiceBlockedForPdf
Change-Id: I2c896bfb98f061cde36b5b2587b1c98d62d62c46
Fixed: 519988071
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7988818
Commit-Queue: Tzarial <zork@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1652349}
---

diff --git a/content/browser/renderer_host/render_frame_host_impl.cc b/content/browser/renderer_host/render_frame_host_impl.cc
index 869a73d3..5d6980e0 100644
--- a/content/browser/renderer_host/render_frame_host_impl.cc
+++ b/content/browser/renderer_host/render_frame_host_impl.cc
@@ -14799,6 +14799,11 @@
 
 void RenderFrameHostImpl::CreateNotificationService(
     mojo::PendingReceiver<blink::mojom::NotificationService> receiver) {
+  if (GetSiteInstance()->GetSiteInfo().is_pdf()) {
+    mojo::ReportBadMessage(
+        "PDF renderers may not bind blink.mojom.NotificationService");
+    return;
+  }
   GetProcess()->CreateNotificationService(
       GetGlobalId(),
       RenderProcessHost::NotificationServiceCreatorType::kDocument,
diff --git a/content/browser/renderer_host/render_frame_host_impl_unittest.cc b/content/browser/renderer_host/render_frame_host_impl_unittest.cc
index c1680ec5c..7051409 100644
--- a/content/browser/renderer_host/render_frame_host_impl_unittest.cc
+++ b/content/browser/renderer_host/render_frame_host_impl_unittest.cc
@@ -13,6 +13,7 @@
 #include "build/buildflag.h"
 #include "components/input/timeout_monitor.h"
 #include "content/browser/renderer_host/navigation_controller_impl.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/common/content_navigation_policy.h"
 #include "content/common/features.h"
 #include "content/public/browser/cors_origin_pattern_setter.h"
@@ -27,6 +28,8 @@
 #include "content/test/test_render_frame_host.h"
 #include "content/test/test_render_view_host.h"
 #include "content/test/test_web_contents.h"
+#include "mojo/public/cpp/test_support/fake_message_dispatch_context.h"
+#include "mojo/public/cpp/test_support/test_utils.h"
 #include "net/base/features.h"
 #include "net/base/isolation_info.h"
 #include "net/base/network_isolation_partition.h"
@@ -44,6 +47,7 @@
 #include "third_party/blink/public/common/runtime_feature_state/runtime_feature_state_read_context.h"
 #include "third_party/blink/public/common/storage_key/storage_key.h"
 #include "third_party/blink/public/mojom/favicon/favicon_url.mojom.h"
+#include "third_party/blink/public/mojom/notifications/notification_service.mojom.h"
 #include "third_party/blink/public/mojom/webauthn/authenticator.mojom.h"
 #include "url/gurl.h"
 #include "url/origin.h"
@@ -1826,4 +1830,26 @@
                   .is_secure_context_root);
 }
 
+TEST_F(RenderFrameHostImplTest, NotificationServiceBlockedForPdf) {
+  UrlInfo url_info(
+      UrlInfoInit(GURL("https://foo.com/document.pdf"))
+          .WithEmbedderIsolationInfo(EmbedderIsolationInfo::CreateForPdf()));
+  scoped_refptr<SiteInstanceImpl> pdf_instance =
+      SiteInstanceImpl::CreateForUrlInfo(GetBrowserContext(), url_info,
+                                         /*is_guest=*/false,
+                                         /*is_fenced=*/false,
+                                         /*is_fixed_storage_partition=*/false);
+  std::unique_ptr<TestWebContents> pdf_web_contents =
+      TestWebContents::Create(GetBrowserContext(), pdf_instance);
+  TestRenderFrameHost* pdf_rfh = pdf_web_contents->GetPrimaryMainFrame();
+
+  mojo::FakeMessageDispatchContext fake_dispatch_context;
+  mojo::test::BadMessageObserver bad_message_observer;
+  mojo::Remote<blink::mojom::NotificationService> service;
+  pdf_rfh->CreateNotificationService(service.BindNewPipeAndPassReceiver());
+
+  EXPECT_EQ("PDF renderers may not bind blink.mojom.NotificationService",
+            bad_message_observer.WaitForBadMessage());
+}
+
 }  // namespace content

diff --git a/content/browser/renderer_host/render_frame_host_impl_unittest.cc b/content/browser/renderer_host/render_frame_host_impl_unittest.cc
index c1680ec5c..7051409 100644
--- a/content/browser/renderer_host/render_frame_host_impl_unittest.cc
+++ b/content/browser/renderer_host/render_frame_host_impl_unittest.cc
@@ -13,6 +13,7 @@
 #include "build/buildflag.h"
 #include "components/input/timeout_monitor.h"
 #include "content/browser/renderer_host/navigation_controller_impl.h"
+#include "content/browser/site_instance_impl.h"
 #include "content/common/content_navigation_policy.h"
 #include "content/common/features.h"
 #include "content/public/browser/cors_origin_pattern_setter.h"
@@ -27,6 +28,8 @@
 #include "content/test/test_render_frame_host.h"
 #include "content/test/test_render_view_host.h"
 #include "content/test/test_web_contents.h"
+#include "mojo/public/cpp/test_support/fake_message_dispatch_context.h"
+#include "mojo/public/cpp/test_support/test_utils.h"
 #include "net/base/features.h"
 #include "net/base/isolation_info.h"
 #include "net/base/network_isolation_partition.h"
@@ -44,6 +47,7 @@
 #include "third_party/blink/public/common/runtime_feature_state/runtime_feature_state_read_context.h"
 #include "third_party/blink/public/common/storage_key/storage_key.h"
 #include "third_party/blink/public/mojom/favicon/favicon_url.mojom.h"
+#include "third_party/blink/public/mojom/notifications/notification_service.mojom.h"
 #include "third_party/blink/public/mojom/webauthn/authenticator.mojom.h"
 #include "url/gurl.h"
 #include "url/origin.h"
@@ -1826,4 +1830,26 @@
                   .is_secure_context_root);
 }
 
+TEST_F(RenderFrameHostImplTest, NotificationServiceBlockedForPdf) {
+  UrlInfo url_info(
+      UrlInfoInit(GURL("https://foo.com/document.pdf"))
+          .WithEmbedderIsolationInfo(EmbedderIsolationInfo::CreateForPdf()));
+  scoped_refptr<SiteInstanceImpl> pdf_instance =
+      SiteInstanceImpl::CreateForUrlInfo(GetBrowserContext(), url_info,
+                                         /*is_guest=*/false,
+                                         /*is_fenced=*/false,
+                                         /*is_fixed_storage_partition=*/false);
+  std::unique_ptr<TestWebContents> pdf_web_contents =
+      TestWebContents::Create(GetBrowserContext(), pdf_instance);
+  TestRenderFrameHost* pdf_rfh = pdf_web_contents->GetPrimaryMainFrame();
+
+  mojo::FakeMessageDispatchContext fake_dispatch_context;
+  mojo::test::BadMessageObserver bad_message_observer;
+  mojo::Remote<blink::mojom::NotificationService> service;
+  pdf_rfh->CreateNotificationService(service.BindNewPipeAndPassReceiver());
+
+  EXPECT_EQ("PDF renderers may not bind blink.mojom.NotificationService",
+            bad_message_observer.WaitForBadMessage());
+}
+
 }  // namespace content