michael@0: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "sandbox/win/src/window.h"
michael@0: 
michael@0: #include <aclapi.h>
michael@0: 
michael@0: #include "base/logging.h"
michael@0: #include "base/memory/scoped_ptr.h"
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: // Gets the security attributes of a window object referenced by |handle|. The
michael@0: // lpSecurityDescriptor member of the SECURITY_ATTRIBUTES parameter returned
michael@0: // must be freed using LocalFree by the caller.
michael@0: bool GetSecurityAttributes(HANDLE handle, SECURITY_ATTRIBUTES* attributes) {
michael@0:   attributes->bInheritHandle = FALSE;
michael@0:   attributes->nLength = sizeof(SECURITY_ATTRIBUTES);
michael@0: 
michael@0:   PACL dacl = NULL;
michael@0:   DWORD result = ::GetSecurityInfo(handle, SE_WINDOW_OBJECT,
michael@0:                                    DACL_SECURITY_INFORMATION, NULL, NULL, &dacl,
michael@0:                                    NULL, &attributes->lpSecurityDescriptor);
michael@0:   if (ERROR_SUCCESS == result)
michael@0:     return true;
michael@0: 
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: }
michael@0: 
michael@0: namespace sandbox {
michael@0: 
michael@0: ResultCode CreateAltWindowStation(HWINSTA* winsta) {
michael@0:   // Get the security attributes from the current window station; we will
michael@0:   // use this as the base security attributes for the new window station.
michael@0:   SECURITY_ATTRIBUTES attributes = {0};
michael@0:   if (!GetSecurityAttributes(::GetProcessWindowStation(), &attributes)) {
michael@0:     return SBOX_ERROR_CANNOT_CREATE_WINSTATION;
michael@0:   }
michael@0: 
michael@0:   // Create the window station using NULL for the name to ask the os to
michael@0:   // generate it.
michael@0:   // TODO(nsylvain): don't ask for WINSTA_ALL_ACCESS if we don't need to.
michael@0:   *winsta = ::CreateWindowStationW(NULL, 0, WINSTA_ALL_ACCESS, &attributes);
michael@0:   LocalFree(attributes.lpSecurityDescriptor);
michael@0: 
michael@0:   if (*winsta)
michael@0:     return SBOX_ALL_OK;
michael@0: 
michael@0:   return SBOX_ERROR_CANNOT_CREATE_WINSTATION;
michael@0: }
michael@0: 
michael@0: ResultCode CreateAltDesktop(HWINSTA winsta, HDESK* desktop) {
michael@0:   std::wstring desktop_name = L"sbox_alternate_desktop_";
michael@0: 
michael@0:   // Append the current PID to the desktop name.
michael@0:   wchar_t buffer[16];
michael@0:   _snwprintf_s(buffer, sizeof(buffer) / sizeof(wchar_t), L"0x%X",
michael@0:                ::GetCurrentProcessId());
michael@0:   desktop_name += buffer;
michael@0: 
michael@0:   // Get the security attributes from the current desktop, we will use this as
michael@0:   // the base security attributes for the new desktop.
michael@0:   SECURITY_ATTRIBUTES attributes = {0};
michael@0:   if (!GetSecurityAttributes(GetThreadDesktop(GetCurrentThreadId()),
michael@0:                              &attributes)) {
michael@0:     return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
michael@0:   }
michael@0: 
michael@0:   // Back up the current window station, in case we need to switch it.
michael@0:   HWINSTA current_winsta = ::GetProcessWindowStation();
michael@0: 
michael@0:   if (winsta) {
michael@0:     // We need to switch to the alternate window station before creating the
michael@0:     // desktop.
michael@0:     if (!::SetProcessWindowStation(winsta)) {
michael@0:       ::LocalFree(attributes.lpSecurityDescriptor);
michael@0:       return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   // Create the destkop.
michael@0:   // TODO(nsylvain): don't ask for GENERIC_ALL if we don't need to.
michael@0:   *desktop = ::CreateDesktop(desktop_name.c_str(), NULL, NULL, 0, GENERIC_ALL,
michael@0:                              &attributes);
michael@0:   ::LocalFree(attributes.lpSecurityDescriptor);
michael@0: 
michael@0:   if (winsta) {
michael@0:     // Revert to the right window station.
michael@0:     if (!::SetProcessWindowStation(current_winsta)) {
michael@0:       return SBOX_ERROR_FAILED_TO_SWITCH_BACK_WINSTATION;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (*desktop)
michael@0:     return SBOX_ALL_OK;
michael@0: 
michael@0:   return SBOX_ERROR_CANNOT_CREATE_DESKTOP;
michael@0: }
michael@0: 
michael@0: std::wstring GetWindowObjectName(HANDLE handle) {
michael@0:   // Get the size of the name.
michael@0:   DWORD size = 0;
michael@0:   ::GetUserObjectInformation(handle, UOI_NAME, NULL, 0, &size);
michael@0: 
michael@0:   if (!size) {
michael@0:     NOTREACHED();
michael@0:     return std::wstring();
michael@0:   }
michael@0: 
michael@0:   // Create the buffer that will hold the name.
michael@0:   scoped_ptr<wchar_t[]> name_buffer(new wchar_t[size]);
michael@0: 
michael@0:   // Query the name of the object.
michael@0:   if (!::GetUserObjectInformation(handle, UOI_NAME, name_buffer.get(), size,
michael@0:                                   &size)) {
michael@0:     NOTREACHED();
michael@0:     return std::wstring();
michael@0:   }
michael@0: 
michael@0:   return std::wstring(name_buffer.get());
michael@0: }
michael@0: 
michael@0: std::wstring GetFullDesktopName(HWINSTA winsta, HDESK desktop) {
michael@0:   if (!desktop) {
michael@0:     NOTREACHED();
michael@0:     return std::wstring();
michael@0:   }
michael@0: 
michael@0:   std::wstring name;
michael@0:   if (winsta) {
michael@0:     name = GetWindowObjectName(winsta);
michael@0:     name += L'\\';
michael@0:   }
michael@0: 
michael@0:   name += GetWindowObjectName(desktop);
michael@0:   return name;
michael@0: }
michael@0: 
michael@0: }  // namespace sandbox