namespace Tools
{ #region Using directives.
using System;
using System.Security.Principal;
using System.Runtime.InteropServices;
using System.ComponentModel;
#endregion
public class Impersonator :
IDisposable
{ #region Public methods.
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;
private const int LOGON32_LOGON_NEW_CREDENTIALS = 9;
#endregion
#region Private member.
private void ImpersonateValidUser(
string userName,
string domain,
string password)
{ WindowsIdentity tempWindowsIdentity = null;
IntPtr token = IntPtr.Zero;
IntPtr tokenDuplicate = IntPtr.Zero;
if (userName != null && domain != null && password != null)
{ try
{ if (RevertToSelf())
{ if (LogonUser(
userName,
domain,
password,
LOGON32_LOGON_NEW_CREDENTIALS,
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);
}
}
}
}
private void UndoImpersonation()
{ if (impersonationContext != null)
{ impersonationContext.Undo();
}
}
private WindowsImpersonationContext impersonationContext = null;
#endregion
}
}