[Win10 sandbox mitigations] Four new Win10 mitigations added.

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 680 matching lines @@
       cmd_line->HasSwitch(switches::kNoSandbox)) {
     base::Process process =
         base::LaunchProcess(*cmd_line, base::LaunchOptions());
     // TODO(rvargas) crbug.com/417532: Don't share a raw handle.
     g_broker_services->AddTargetPeer(process.Handle());
     return process.Pass();
   }
 
   sandbox::TargetPolicy* policy = g_broker_services->CreatePolicy();
 
-  sandbox::MitigationFlags mitigations = sandbox::MITIGATION_HEAP_TERMINATE |
-                                         sandbox::MITIGATION_BOTTOM_UP_ASLR |
-                                         sandbox::MITIGATION_DEP |
-                                         sandbox::MITIGATION_DEP_NO_ATL_THUNK |
-                                         sandbox::MITIGATION_SEHOP;
+  // Pre-startup mitigations.
+  sandbox::MitigationFlags mitigations =
+      sandbox::MITIGATION_HEAP_TERMINATE |
+      sandbox::MITIGATION_BOTTOM_UP_ASLR |
+      sandbox::MITIGATION_DEP |
+      sandbox::MITIGATION_DEP_NO_ATL_THUNK |
+      sandbox::MITIGATION_SEHOP;
 
   if (policy->SetProcessMitigations(mitigations) != sandbox::SBOX_ALL_OK)
     return base::Process();
 
 #if !defined(NACL_WIN64)
   if (type_str == switches::kRendererProcess &&
       IsWin32kRendererLockdownEnabled()) {
     if (!AddWin32kLockdownPolicy(policy))
       return base::Process();
   }
 #endif
 
+  // Post-startup mitigations.
   mitigations = sandbox::MITIGATION_STRICT_HANDLE_CHECKS |
                 sandbox::MITIGATION_DLL_SEARCH_ORDER;
 
   if (policy->SetDelayedProcessMitigations(mitigations) != sandbox::SBOX_ALL_OK)
     return base::Process();
 
   SetJobLevel(*cmd_line, sandbox::JOB_LOCKDOWN, 0, policy);
 
   if (!delegate->DisableDefaultPolicy()) {
     if (!AddPolicyForSandboxedProcess(policy))
@@ skipping 131 matching lines @@
   }
 
   return false;
 }
 
 bool BrokerAddTargetPeer(HANDLE peer_process) {
   return g_broker_services->AddTargetPeer(peer_process) == sandbox::SBOX_ALL_OK;
 }
 
 }  // namespace content