Windows sbox: Warmup locales before sandbox lockdown (and tests)

sandbox/win/src/target_services.cc

Index: sandbox/win/src/target_services.cc
diff --git a/sandbox/win/src/target_services.cc b/sandbox/win/src/target_services.cc
index 116f0c929b81ee71ac9d5f7f686593e56a3e78f4..e10f7ca411488e0393d8ec84c9d32266fbff2aaa 100644
--- a/sandbox/win/src/target_services.cc
+++ b/sandbox/win/src/target_services.cc
@@ -59,6 +59,44 @@ bool CloseOpenHandles(bool* is_csrss_connected) {
   return true;
 }
 
+// GetUserDefaultLocaleName is not available on WIN XP.  So we'll
+// load it on-the-fly.
+const wchar_t kKernel32DllName[] = L"kernel32.dll";
+typedef decltype(GetUserDefaultLocaleName)* GetUserDefaultLocaleNameFunction;
+
+// Warm up language subsystems before the sandbox is turned on.
+// Tested on Win8.1 x64:
+// This needs to happen after RevertToSelf() is called, because (at least) in
+// the case of GetUserDefaultLCID() it checks the TEB to see if the process is
+// impersonating (TEB!IsImpersonating). If it is, the cached locale information
+// is not used, nor is it set. Therefore, calls after RevertToSelf() will not
+// have warmed-up values to use.
+bool WarmupWindowsLocales() {
+  // NOTE(liamjm): When last checked (Win 8.1 x64) it wasn't necessary to
+  // warmup all of these functions, but let's not assume that.
+  ::GetUserDefaultLangID();
+  ::GetUserDefaultLCID();
+  if (base::win::GetVersion() >= base::win::VERSION_VISTA) {
+    static GetUserDefaultLocaleNameFunction GetUserDefaultLocaleName_func =
+        NULL;
+    if (!GetUserDefaultLocaleName_func) {
+      HMODULE kernel32_dll = ::GetModuleHandle(kKernel32DllName);
+      if (!kernel32_dll) {
+        return false;
+      }
+      GetUserDefaultLocaleName_func =
+          reinterpret_cast<GetUserDefaultLocaleNameFunction>(
+              GetProcAddress(kernel32_dll, "GetUserDefaultLocaleName"));
+      if (!GetUserDefaultLocaleName_func) {
+        return false;
+      }
+    }
+    wchar_t localeName[LOCALE_NAME_MAX_LENGTH] = {0};
+    return (0 != GetUserDefaultLocaleName_func(
+                     localeName, LOCALE_NAME_MAX_LENGTH * sizeof(wchar_t)));
+  }
+  return true;
+}
 
 // Used as storage for g_target_services, because other allocation facilities
 // are not available early. We can't use a regular function static because on
@@ -97,6 +135,8 @@ void TargetServicesBase::LowerToken() {
     ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_FLUSHANDLES);
   if (ERROR_SUCCESS != ::RegDisablePredefinedCache())
     ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_CACHEDISABLE);
+  if (!WarmupWindowsLocales())
+    ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_WARMUP);
   bool is_csrss_connected = true;
   if (!CloseOpenHandles(&is_csrss_connected))
     ::TerminateProcess(::GetCurrentProcess(), SBOX_FATAL_CLOSEHANDLES);