Impersonating a Windows user

c#, impersonation, windows

Solution

try this :

[DllImport("advapi32.dll", SetLastError = true)]
    public static extern bool LogonUser(
            string lpszUsername,
            string lpszDomain,
            string lpszPassword,
            int dwLogonType,
            int dwLogonProvider,
            out IntPtr phToken);

Usage :

IntPtr userToken = IntPtr.Zero;

bool success = External.LogonUser(
  "john.doe", 
  "domain.com", 
  "MyPassword", 
  (int) AdvApi32Utility.LogonType.LOGON32_LOGON_INTERACTIVE, //2
  (int) AdvApi32Utility.LogonProvider.LOGON32_PROVIDER_DEFAULT, //0
  out userToken);

if (!success)
{
  throw new SecurityException("Logon user failed");
}

using (WindowsIdentity.Impersonate(userToken))
{
 Process.Start("explorer.exe", @"/root,\\server01-Prod\abc");
}

Problem

I am using the code to impersonate a user account to get access to a file share. ``` public class Impersonator : IDisposable { #region Public methods. // ------------------------------------------------------------------ /// <summary> /// Constructor. Starts the impersonation with the given credentials. /// Please note that the account that instantiates the Impersonator class /// needs to have the 'Act as part of operating system' privilege set. /// </summary> /// <param name="userName">The name of the user to act as.</param> /// <param name="domainName">The domain name of the user to act as.</param> /// <param name="password">The password of the user to act as.</param> public Impersonator( string userName, string domainName, string password ) { ImpersonateValidUser( userName, domainName, password ); } // ------------------------------------------------------------------ #endregion #region IDisposable member. // ------------------------------------------------------------------ public void Dispose() { UndoImpersonation(); } // ------------------------------------------------------------------ #endregion #region P/Invoke. // ------------------------------------------------------------------ [DllImport("advapi32.dll", SetLastError=true)] private static extern int LogonUser( string lpszUserName, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] private static extern int DuplicateToken( IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] private static extern bool RevertToSelf(); [DllImport("kernel32.dll", CharSet=CharSet.Auto)] private static extern bool CloseHandle( IntPtr handle); private const int LOGON32_LOGON_INTERACTIVE = 2; private const int LOGON32_PROVIDER_DEFAULT = 0; // ------------------------------------------------------------------ #endregion #region Private member. // ------------------------------------------------------------------ /// <summary> /// Does the actual impersonation. /// </summary> /// <param name="userName">The name of the user to act as.</param> /// <param name="domainName">The domain name of the user to act as.</param> /// <param name="password">The password of the user to act as.</param> private void ImpersonateValidUser( string userName, string domain, string password ) { WindowsIdentity tempWindowsIdentity = null; IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; try { if ( RevertToSelf() ) { if ( LogonUser( userName, domain, password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref token ) != 0 ) { if ( DuplicateToken( token, 2, ref tokenDuplicate ) != 0 ) { tempWindowsIdentity = new WindowsIdentity( tokenDuplicate ); impersonationContext = tempWindowsIdentity.Impersonate(); } else { throw new Win32Exception( Marshal.GetLastWin32Error() ); } } else { throw new Win32Exception( Marshal.GetLastWin32Error() ); } } else { throw new Win32Exception( Marshal.GetLastWin32Error() ); } } finally { if ( token!= IntPtr.Zero ) { CloseHandle( token ); } if ( tokenDuplicate!=IntPtr.Zero ) { CloseHandle( tokenDuplicate ); } } } /// <summary> /// Reverts the impersonation. /// </summary> private void UndoImpersonation() { if ( impersonationContext!=null ) { impersonationContext.Undo(); } } private WindowsImpersonationContext impersonationContext = null; // ------------------------------------------------------------------ #endregion } ``` Then using: ``` using (new Impersonator("username", "domain", "password")) { Process.Start("explorer.exe", @"/root,\\server01-Prod\abc"); } ``` I get an "Access Denied" error. This user supposely has access to this share. I can map a drive, use "net use" but this code will not work. Now I am thinking it is the code. Does anyone see anything? Is there a better way of doing this?

Original source