Make string_util::WriteInto() DCHECK() that the supplied |length_with_null| > 1, meaning that the...

chrome_frame/chrome_tab.cc

 // Copyright (c) 2011 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.
 
 // chrome_tab.cc : Implementation of DLL Exports.
 
 // Need to include this before the ATL headers below.
 #include "chrome_frame/chrome_tab.h"
 
 #include <atlsecurity.h>
@@ skipping 449 matching lines @@
   // Read SDDL string from backup key
   bool ReadBackupKey(std::wstring* sddl) {
     RegKey backup_key(HKEY_LOCAL_MACHINE, backup_key_name_.c_str(), KEY_READ);
     if (!backup_key.Valid())
       return false;
 
     DWORD len = 0;
     DWORD reg_type = REG_NONE;
     if (backup_key.ReadValue(NULL, NULL, &len, &reg_type) != ERROR_SUCCESS)
       return false;
+    DCHECK_EQ(0u, len % sizeof(wchar_t));
 
-    if (reg_type != REG_SZ)
+    if ((len == 0) || (reg_type != REG_SZ))
       return false;
 
     size_t wchar_count = 1 + len / sizeof(wchar_t);
     if (backup_key.ReadValue(NULL, WriteInto(sddl, wchar_count), &len,
                              &reg_type) != ERROR_SUCCESS) {
       return false;
     }
 
     return true;
   }
@@ skipping 434 matching lines @@
   HRESULT hr = CustomRegistration(ALL, FALSE, false);
   return hr;
 }
 
 // Object entries go here instead of with each object, so that we can move
 // the objects to a lib. Also reduces magic.
 OBJECT_ENTRY_AUTO(CLSID_ChromeFrameBHO, Bho)
 OBJECT_ENTRY_AUTO(__uuidof(ChromeActiveDocument), ChromeActiveDocument)
 OBJECT_ENTRY_AUTO(__uuidof(ChromeFrame), ChromeFrameActivex)
 OBJECT_ENTRY_AUTO(__uuidof(ChromeProtocol), ChromeProtocol)