From d283fa55777a691531f3eceb8020dd890548e680 Mon Sep 17 00:00:00 2001
From: Danil Somsikov <dsv@chromium.org>
Date: Wed, 01 Apr 2026 01:21:37 -0700
Subject: [PATCH] Restrict Page.setSPCTransactionMode and Page.setRPHRegistrationMode to trusted DevTools clients

The experimental DevTools commands Page.setSPCTransactionMode and
Page.setRPHRegistrationMode lacked trust restrictions, allowing
untrusted DevTools clients (such as Chrome extensions with the
`debugger` permission) to automatically accept dialogs without user
interaction.

For Page.setSPCTransactionMode, this bypassed the primary UI where
users review transaction details (payee, amount) for Secure Payment
Confirmation (SPC), leaving only a generic OS-level biometric prompt
that lacks context and could potentially be exploited to authorize
tampered payments.

Similarly, Page.setRPHRegistrationMode could be exploited to silently
accept custom protocol handler registration prompts, bypassing user
consent.

Fixed: 496426191, 496373088
Change-Id: I49cafe716e5c81c3715f8bde30e579d4cc9a01b8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7707756
Commit-Queue: Danil Somsikov <dsv@chromium.org>
Auto-Submit: Danil Somsikov <dsv@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1608355}
---

diff --git a/chrome/browser/devtools/chrome_devtools_session.cc b/chrome/browser/devtools/chrome_devtools_session.cc
index e01701b..07560364 100644
--- a/chrome/browser/devtools/chrome_devtools_session.cc
+++ b/chrome/browser/devtools/chrome_devtools_session.cc
@@ -61,7 +61,8 @@
     if (IsDomainAvailableToUntrustedClient<PageHandler>() ||
         channel->GetClient()->IsTrusted()) {
       page_handler_ = std::make_unique<PageHandler>(
-          agent_host, agent_host->GetWebContents(), &dispatcher_);
+          agent_host, agent_host->GetWebContents(), &dispatcher_,
+          channel->GetClient()->IsTrusted());
     }
     if (IsDomainAvailableToUntrustedClient<SecurityHandler>() ||
         channel->GetClient()->IsTrusted()) {
diff --git a/chrome/browser/devtools/protocol/page_handler.cc b/chrome/browser/devtools/protocol/page_handler.cc
index c5c79bf..bc3122f4 100644
--- a/chrome/browser/devtools/protocol/page_handler.cc
+++ b/chrome/browser/devtools/protocol/page_handler.cc
@@ -37,8 +37,11 @@
 
 PageHandler::PageHandler(scoped_refptr<content::DevToolsAgentHost> agent_host,
                          content::WebContents* web_contents,
-                         protocol::UberDispatcher* dispatcher)
-    : agent_host_(agent_host), web_contents_(web_contents->GetWeakPtr()) {
+                         protocol::UberDispatcher* dispatcher,
+                         bool is_trusted)
+    : agent_host_(agent_host),
+      web_contents_(web_contents->GetWeakPtr()),
+      is_trusted_(is_trusted) {
   protocol::Page::Dispatcher::wire(dispatcher, this);
 }
 
@@ -86,6 +89,11 @@
 
 protocol::Response PageHandler::SetSPCTransactionMode(
     const protocol::String& mode) {
+  if (!is_trusted_) {
+    return protocol::Response::ServerError(
+        "Permission denied: Page.setSPCTransactionMode requires a trusted "
+        "client");
+  }
   if (!web_contents_)
     return protocol::Response::ServerError("No web contents to host a dialog.");
 
@@ -117,6 +125,11 @@
   if (!web_contents_) {
     return protocol::Response::ServerError("No web contents to host a dialog.");
   }
+  if (!is_trusted_) {
+    return protocol::Response::ServerError(
+        "Permission denied: Page.setRPHRegistrationMode requires a trusted "
+        "client");
+  }
 
   custom_handlers::RphRegistrationMode rph_mode =
       custom_handlers::RphRegistrationMode::kNone;
diff --git a/chrome/browser/devtools/protocol/page_handler.h b/chrome/browser/devtools/protocol/page_handler.h
index 90b717f..4c2c12fc 100644
--- a/chrome/browser/devtools/protocol/page_handler.h
+++ b/chrome/browser/devtools/protocol/page_handler.h
@@ -31,7 +31,8 @@
  public:
   PageHandler(scoped_refptr<content::DevToolsAgentHost> agent_host,
               content::WebContents* web_contents,
-              protocol::UberDispatcher* dispatcher);
+              protocol::UberDispatcher* dispatcher,
+              bool is_trusted);
 
   PageHandler(const PageHandler&) = delete;
   PageHandler& operator=(const PageHandler&) = delete;
@@ -99,6 +100,7 @@
   base::WeakPtr<content::WebContents> web_contents_;
 
   bool enabled_ = false;
+  const bool is_trusted_;
 
   base::WeakPtrFactory<PageHandler> weak_ptr_factory_{this};
 };