Clamp open file name size.

chrome/common/win_util.cc

 // Copyright (c) 2006-2008 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/common/win_util.h"
 
 #include <atlbase.h>
 #include <atlapp.h>
 #include <commdlg.h>
 #include <dwmapi.h>
@@ skipping 377 matching lines @@
 bool SaveFileAsWithFilter(HWND owner,
                           const std::wstring& suggested_name,
                           const wchar_t* filter,
                           const std::wstring& def_ext,
                           unsigned* index,
                           std::wstring* final_name) {
   DCHECK(final_name);
 
   // Initially populated by the file component of 'suggested_name', this buffer
   // will be written into by Windows when the user is done with the dialog box.
-  wchar_t file_name[MAX_PATH+1];
   std::wstring file_part = file_util::GetFilenameFromPath(suggested_name);
-  memcpy(file_name,
-         file_part.c_str(),
-         (file_part.length()+1) * sizeof(wchar_t));
+
+  // This will clamp the number of characters copied from the supplied path
+  // to the value of MAX_PATH.
+  size_t name_size = std::min(file_part.length() + 1,
+                              static_cast<size_t>(MAX_PATH));
+  wchar_t file_name[MAX_PATH];
+  memcpy(file_name, file_part.c_str(), name_size * sizeof(wchar_t));
+  file_name[MAX_PATH - 1] = '\0';
 
   OPENFILENAME save_as;
   // We must do this otherwise the ofn's FlagsEx may be initialized to random
   // junk in release builds which can cause the Places Bar not to show up!
   ZeroMemory(&save_as, sizeof(save_as));
   save_as.lStructSize = sizeof(OPENFILENAME);
   save_as.hwndOwner = owner;
   save_as.hInstance = NULL;
 
   save_as.lpstrFilter = &filter[0];
@@ skipping 398 matching lines @@
   std::wstring localized_caption;
   const wchar_t* caption_ptr = caption.c_str();
   if (l10n_util::AdjustStringForLocaleDirection(caption, &localized_caption))
     caption_ptr = localized_caption.c_str();
 
   return ::MessageBox(hwnd, text_ptr, caption_ptr, actual_flags);
 }
 
 }  // namespace win_util