Add support for alternate window station.

chrome/renderer/renderer_main_platform_delegate_win.cc

 // Copyright (c) 2009 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 "chrome/renderer/renderer_main_platform_delegate.h"
 
 #include "base/command_line.h"
 #include "base/gfx/native_theme.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/injection_test_dll.h"
 #include "sandbox/src/sandbox.h"
 
 namespace {
 
 // In order to have Theme support, we need to connect to the theme service.
 // This needs to be done before we lock down the renderer. Officially this
 // can be done with OpenThemeData() but it fails unless you pass a valid
 // window at least the first time. Interestingly, the very act of creating a
 // window also sets the connection to the theme service.
-void EnableThemeSupportForRenderer() {
+void EnableThemeSupportForRenderer(bool no_sandbox) {
+  HWINSTA current = NULL;
+  HWINSTA winsta0 = NULL;
+  
+  if (!no_sandbox) {
+    current = ::GetProcessWindowStation();
+    winsta0 = ::OpenWindowStationW(L"WinSta0", FALSE, GENERIC_READ);
+    if (!winsta0 || !::SetProcessWindowStation(winsta0)) {
+      // Could not set the alternate window station. There is a possibility
+      // that the theme wont be correctly initialized on XP.
+      NOTREACHED();

[rvargas (doing something else), 2009/05/20 01:21:01]

nit: could add a log message here?

+    }
+  }
+
+  // Create a windows on the WinSta0 to initialize theme support.

[cpu_(ooo_6.6-7.5), 2009/05/20 01:51:22]

don't need the comment, see lines 16-20.

   HWND window = ::CreateWindowExW(0, L"Static", L"", WS_POPUP | WS_DISABLED,
                                   CW_USEDEFAULT, 0, 0, 0,  HWND_MESSAGE, NULL, 
                                   ::GetModuleHandleA(NULL), NULL);
+  ::DestroyWindow(window);

[rvargas (doing something else), 2009/05/20 01:21:01]

nit: could you move the !window check here?

+
+  if (!no_sandbox) {
+    // Revert the window station.
+    if (!current || !::SetProcessWindowStation(current)) {
+      // We failed to switch back to the secure window station. This might
+      // confuse the renderer enough that we should kill it now.
+      CHECK(false) << "Failed to restore alternate window station";
+    }
+
+    if (!CloseWindowStation(winsta0)) {

[cpu_(ooo_6.6-7.5), 2009/05/20 01:51:22]

it seems the style here is :: for windows calls

+      // We might be leaking a winsta0 handle.  This is a security risk, but
+      // since we allow fail over to no desktop protection in low memory
+      // condition, this is not a big risk.
+      NOTREACHED();
+    }
+  }
+
   if (!window) {
     DLOG(WARNING) << "failed to enable theme support";
     return;
   }
-  ::DestroyWindow(window);
 }
 
 }  // namespace
 
 RendererMainPlatformDelegate::RendererMainPlatformDelegate(
     const MainFunctionParams& parameters)
         : parameters_(parameters),
           sandbox_test_module_(NULL) {
 }
 
 RendererMainPlatformDelegate::~RendererMainPlatformDelegate() {
 }
 
 void RendererMainPlatformDelegate::PlatformInitialize() {
   // Be mindful of what resources you acquire here. They can be used by
   // malicious code if the renderer gets compromised.
-  EnableThemeSupportForRenderer();
+  const CommandLine& command_line = parameters_.command_line_;
+  bool no_sandbox = command_line.HasSwitch(switches::kNoSandbox);
+  EnableThemeSupportForRenderer(no_sandbox);
 }
 
 void RendererMainPlatformDelegate::PlatformUninitialize() {
 }
 
 bool RendererMainPlatformDelegate::InitSandboxTests(bool no_sandbox) {
   const CommandLine& command_line = parameters_.command_line_;
 
   DLOG(INFO) << "Started renderer with " << command_line.command_line_string();
 
@@ skipping 32 matching lines @@
                                                           kRenderTestCall));
     DCHECK(run_security_tests);
     if (run_security_tests) {
       int test_count = 0;
       DLOG(INFO) << "Running renderer security tests";
       BOOL result = run_security_tests(&test_count);
       CHECK(result) << "Test number " << test_count << " has failed.";
     }
   }
 }