Impersonate User (I found that it is not that simple in VB6)

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  13 years ago

  by Kassem

  Kassem Baalbaki

  Riyadh, Saudi Arabia

  Joined 14 years ago

  Hi,

  I previously used a function in C# that allowed users to copy files from the server through passing administrative logon information using Logon, ImpersonateLoggedOnUser and DuplicateToken APIs.

   

  Now am trying doing it in VB6, it is not that easy, in .net there is a lot of support for those APIs as well as a lot of predefined variables and types.

   

  I reached a level in which am being able to logon as the administrative user but am not being able to stick this logon information with the handle needed to open the remote file.

   

  If any one knows better way to logon to remote secured files (I already have administrative user name and password but for security reasons we don’t want to keep the folder accessible all the time but just when accessed through our application) it would be highly appreciated (I have already tried “net use \\server\folder password /user:username” but it is not that reliable).

   

  Any help will be highly appreciated , I have included the code I have already used (some statements may be missing others are not needed, but am still in the trial stage).

  Module

  Public Declare Function LogonUser Lib "advapi32.dll" Alias "LogonUserA" (ByVal lpszUsername As String, ByVal lpszDomain As String, ByVal lpszPassword As String, _

  ByVal dwLogonType As Long, ByVal dwLogonProvider As Long, phToken As Long) As Long

   

  Public Declare Function ImpersonateLoggedOnUser Lib "advapi32.dll" (ByVal hToken As Long) As Long

   

  Public Declare Function RevertToSelf Lib "advapi32.dll" () As Long

   

  Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

   

  Public Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long

   

  Const SW_SHOWNORMAL = 1

   

  Public Declare Function DuplicateToken Lib "advapi32.dll" (ByVal ExistingTokenHandle As Long, ImpersonationLevel As Integer, DuplicateTokenHandle As Long) As Long

   

  Form

  Public Sub Logon(ByVal strAdminUser As String, ByVal strAdminPassword As String, ByVal strAdminDomain As String)

   

      Dim lngLogonType, lngLogonProvider, lngTokenHandle As Long

      Dim blnResult As Boolean

     

      lngLogonType = 2

      lngLogonProvider = 0

      lngTokenHandle = Me.hwnd

     

      blnResult = RevertToSelf()

     

      blnResult = LogonUser(strAdminUser, strAdminDomain, strAdminPassword, lngLogonType, lngLogonProvider, lngTokenHandle)

                                                          

      blnResult = ImpersonateLoggedOnUser(lngTokenHandle)

     

      DuplicateToken lngTokenHandle, 2, 0

     

      ShellExecute lngTokenHandle, vbNullString, "\\Server1\data\a.txt", vbNullString, "\\Server1\data\", 1

     

      CloseHandle (lngTokenHandle)

     

      Logoff

    

  End Sub

   

  Public Sub Logoff()

      

       Dim blnResult As Boolean

       blnResult = RevertToSelf()

    

  End Sub

    

   

  Private Sub Command1_Click()

      

       Logon "xxxusername", "xxxpassword", "xxxdomain"

      

  End Sub

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