Symptoms
This article describes how to use the RegLoadKey registry function to load a user profile into the registry and, subsequently, how to use RegUnLoadKey to unload the user profile. Because RegLoadKey requires the SE_RESTORE_NAME privilege to be successful, this article also uses the OpenProcessToken, LookupPrivilegeValue, and AdjustTokenPrivileges functions.
Resolution
In part, the registry consists of files that store information about a user profile. When this file is loaded, it maps to the HKEY_USERS or HKEY_LOCAL_MACHINE key, whichever is specified in the call to RegLoadKey.
To retrieve user profile-specific information, you can load the NtUser.dat file that is located in the profile path of the user profile that you want to load. It may be necessary to load a hive (user profile) when you try to provide profile-specific data. For example, either the ImpersonateLoggedOnUser function or the CreateProcessAsUser function is generally used to run under a different security context and does not load the profile of that user.
The following steps illustrate how to load NtUser.dat and unload it when finished. These methods are not a threat to security because they only succeed if the calling process and the impersonated user have sufficient privileges.
Step-by-Step ExampleWARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
Create a new Standard EXE project in Visual Basic. Form1 is created by default.Add a TextBox control (Text1) and two CommandButton controls (Command1 and Command2) to Form1.Paste the following code into the General Declarations section of Form1:
Option ExplicitPrivate Type LUIDLowPart As LongHighPart As LongEnd TypePrivate Type LUID_AND_ATTRIBUTESpLuid As LUIDAttributes As LongEnd TypePrivate Type TOKEN_PRIVILEGESPrivilegeCount As LongPrivileges(1) As LUID_AND_ATTRIBUTESEnd TypePrivate Const TOKEN_ADJUST_PRIVLEGES = &H20Private Const TOKEN_QUERY = &H8Private Const SE_PRIVILEGE_ENABLED = &H2Private Const HKEY_USERS = &H80000003Private Const SE_RESTORE_NAME = “SeRestorePrivilege”Private Const SE_BACKUP_NAME = “SeBackupPrivilege”Private Declare Function GetCurrentProcess Lib “kernel32″ () As LongPrivate Declare Function OpenProcessToken Lib “advapi32.dll” _(ByVal ProcessHandle As Long, ByVal DesiredAccess As Long, _TokenHandle As Long) As LongPrivate Declare Function LookupPrivilegeValue Lib “advapi32.dll” Alias _”LookupPrivilegeValueA” (ByVal lpSystemName As String, _ByVal lpName As String, lpLuid As LUID) As LongPrivate Declare Function AdjustTokenPrivileges Lib “advapi32.dll” _(ByVal TokenHandle As Long, ByVal DisableAllPrivileges As Long, _NewState As TOKEN_PRIVILEGES, ByVal BufferLength As Long, _ByVal PreviousState As Long, ByVal ReturnLength As Long) As LongPrivate Declare Function RegLoadKey Lib “advapi32.dll” Alias “RegLoadKeyA” _(ByVal hKey As Long, ByVal lpSubKey As String, ByVal lpFile As String) _As LongPrivate Declare Function RegUnLoadKey Lib “advapi32.dll” Alias “RegUnLoadKeyA” _(ByVal hKey As Long, ByVal lpSubKey As String) As LongPrivate Retval As LongPrivate strKeyName As StringPrivate MyToken As LongPrivate TP As TOKEN_PRIVILEGESPrivate RestoreLuid As LUIDPrivate BackupLuid As LUIDPrivate Sub Form_Load()strKeyName = “keyLoaded”‘ Path to file on Windows NT: C:\WinNT\Profiles\<Profile Name>\NtUser.Dat’ Path to file on Windows 2000: C:\Documents and Settings\<Profile Name>\NtUser.DatText1.Text = “<Path to File>”Command2.Enabled = FalseRetval = OpenProcessToken(GetCurrentProcess, TOKEN_ADJUST_PRIVLEGES _Or TOKEN_QUERY, MyToken)If Retval = 0 Then MsgBox “OpenProcess: ” & Err.LastDllErrorRetval = LookupPrivilegeValue(vbNullString, SE_RESTORE_NAME, _RestoreLuid)If Retval = 0 Then MsgBox “LookupPrivileges: ” & Err.LastDllErrorRetval = LookupPrivilegeValue(vbNullString, SE_BACKUP_NAME, BackupLuid)If Retval = 0 Then MsgBox “LookupPrivileges: ” & RetvalTP.PrivilegeCount = 2TP.Privileges(0).pLuid = RestoreLuidTP.Privileges(0).Attributes = SE_PRIVILEGE_ENABLEDTP.Privileges(1).pLuid = BackupLuidTP.Privileges(1).Attributes = SE_PRIVILEGE_ENABLEDRetval = AdjustTokenPrivileges(MyToken, vbFalse, TP, Len(TP), 0&, 0&)If Retval = 0 Then MsgBox “AdjustTokenPrivileges: ” & Err.LastDllErrorEnd SubPrivate Sub Command1_Click()Retval = RegLoadKey(HKEY_USERS, strKeyName, Text1.Text)If Retval <> 0 Then MsgBox “RegLoadKey: ” & RetvalCommand2.Enabled = TrueEnd SubPrivate Sub Command2_Click()Retval = RegUnLoadKey(HKEY_USERS, strKeyName)If Retval <> 0 Then MsgBox “RegUnloadKey: ” & RetvalEnd SubPrivate Sub Form_Unload(Cancel As Integer)Retval = AdjustTokenPrivileges(MyToken, vbTrue, TP, Len(TP), 0&, 0&)If Retval = 0 Then MsgBox “AdjustTokenPrivileges: ” & Err.LastDllErrorEnd Sub Save the project, and then press the F5 key to run it.Type the path to a specific user profile .dat file, for example:
C:\WinNT\Profiles\Administrator\NtUser.dat and then click Command1.Click Start, click Run, type regedit (on Windows NT) or regedt32 (on Windows 2000), and then click OK.Locate the HKEY_USERS subtree. Notice that this subtree includes the new key, KeyLoaded.In the Visual Basic project, click Command2 to remove this key from the registry.
