[Windows Sandbox] Turn on MITIGATION_EXTENSION_POINT_DISABLE for child processes.

content/common/sandbox_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/common/sandbox_win.h"
 
 #include <stddef.h>
 
 #include <string>
 
@@ skipping 13 matching lines @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
 #include "base/win/iat_patch_function.h"
 #include "base/win/scoped_handle.h"
 #include "base/win/scoped_process_information.h"
 #include "base/win/win_util.h"
 #include "base/win/windows_version.h"
 #include "content/common/content_switches_internal.h"
 #include "content/public/common/content_client.h"
+#include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/sandbox_init.h"
 #include "content/public/common/sandboxed_process_launcher_delegate.h"
 #include "sandbox/win/src/process_mitigations.h"
 #include "sandbox/win/src/sandbox.h"
 #include "sandbox/win/src/sandbox_nt_util.h"
 #include "sandbox/win/src/sandbox_policy_base.h"
 #include "sandbox/win/src/win_utils.h"
 
 #if !defined(NACL_WIN64)
@@ skipping 673 matching lines @@
   sandbox::MitigationFlags mitigations =
       sandbox::MITIGATION_HEAP_TERMINATE |
       sandbox::MITIGATION_BOTTOM_UP_ASLR |
       sandbox::MITIGATION_DEP |
       sandbox::MITIGATION_DEP_NO_ATL_THUNK |
       sandbox::MITIGATION_SEHOP |
       sandbox::MITIGATION_NONSYSTEM_FONT_DISABLE |
       sandbox::MITIGATION_IMAGE_LOAD_NO_REMOTE |
       sandbox::MITIGATION_IMAGE_LOAD_NO_LOW_LABEL;
 
+  if (base::FeatureList::IsEnabled(features::kWinSboxDisableExtensionPoints))
+    mitigations |= sandbox::MITIGATION_EXTENSION_POINT_DISABLE;
+
   sandbox::ResultCode result = sandbox::SBOX_ERROR_GENERIC;
-
   result = policy->SetProcessMitigations(mitigations);
 
   if (result != sandbox::SBOX_ALL_OK)
     return result;
 
 #if !defined(NACL_WIN64)
   if (type_str == switches::kRendererProcess &&
       IsWin32kRendererLockdownEnabled()) {
     result = AddWin32kLockdownPolicy(policy, false);
     if (result != sandbox::SBOX_ALL_OK)
@@ skipping 91 matching lines @@
   }
 
   delegate->PostSpawnTarget(target.process_handle());
 
   CHECK(ResumeThread(target.thread_handle()) != static_cast<DWORD>(-1));
   *process = base::Process(target.TakeProcessHandle());
   return sandbox::SBOX_ALL_OK;
 }
 
 }  // namespace content