Made setting lowbox token a warning.

sandbox/win/src/broker_services.cc

Index: sandbox/win/src/broker_services.cc
diff --git a/sandbox/win/src/broker_services.cc b/sandbox/win/src/broker_services.cc
index 1339abffb6ed6b8f00f0b63f42e4b03d91dda923..92bd2c689ab956e4b57cc5d956d9b0e99503daf6 100644
--- a/sandbox/win/src/broker_services.cc
+++ b/sandbox/win/src/broker_services.cc
@@ -273,6 +273,7 @@ DWORD WINAPI BrokerServicesBase::TargetEventsThread(PVOID param) {
 ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
                                            const wchar_t* command_line,
                                            TargetPolicy* policy,
+                                           ResultCode* last_warning,
                                            PROCESS_INFORMATION* target_info) {
   if (!exe_path)
     return SBOX_ERROR_BAD_PARAMS;
@@ -286,6 +287,7 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
   // the child process.
   static DWORD thread_id = ::GetCurrentThreadId();
   DCHECK(thread_id == ::GetCurrentThreadId());
+  *last_warning = SBOX_ALL_OK;
 
   AutoLock lock(&lock_);
 
@@ -303,6 +305,11 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
       policy_base->MakeTokens(&initial_token, &lockdown_token, &lowbox_token);
   if (SBOX_ALL_OK != result)
     return result;
+  if (lowbox_token.IsValid() &&
+      base::win::GetVersion() < base::win::VERSION_WIN8) {
+    // We don't allow lowbox_token below Windows 8.
+    return SBOX_ERROR_BAD_PARAMS;
+  }
 
   base::win::ScopedHandle job;
   result = policy_base->MakeJobObject(&job);
@@ -407,7 +414,7 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
   base::win::ScopedProcessInformation process_info;
   TargetProcess* target =
       new TargetProcess(std::move(initial_token), std::move(lockdown_token),
-                        std::move(lowbox_token), job.Get(), thread_pool_);
+                        job.Get(), thread_pool_);
 
   DWORD win_result;
   result = target->Create(exe_path, command_line, inherit_handles, startup_info,
@@ -418,6 +425,12 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
     return result;
   }
 
+  if (lowbox_token.IsValid()) {

[Will Harris, 2016/07/12 16:10:59]

comment here on why this does not abort

+    *last_warning = target->AssignLowBoxToken(lowbox_token);
+    if (*last_warning != SBOX_ALL_OK)
+      win_result = ::GetLastError();
+  }
+
   // Now the policy is the owner of the target.
   result = policy_base->AddTarget(target);
 
@@ -451,6 +464,8 @@ ResultCode BrokerServicesBase::SpawnTarget(const wchar_t* exe_path,
   }
 
   *target_info = process_info.Take();
+  if (*last_warning != SBOX_ALL_OK)
+    ::SetLastError(win_result);
   return result;
 }