Impersonating a user programmatically in C# code

Here is how to call it.... public void SampleCallingMethod(Object s, EventArgs e) { if(ImpersonateUser("username", "domain", "password")) { //Insert your code that runs under the security context of a specific user here. doSomethingHere(); UnImpersonation(); } else { //Your impersonation failed. Therefore, include a fail-safe mechanism here. } } Here is the source code.... using System; using System.Web; using System.Web.Security; using System.Security.Principal; using System.Runtime.InteropServices; namespace AuthenticationMapper { ///

/// Use this class to run a section of code as a different user. /// Most of this code was copied from: http://support.microsoft.com/kb/306158 /// Modifications by: Brent Vermilion 9/5/2007 ///

public class Impersonation { WindowsImpersonationContext impersonationContext; #region WIN32 definitions public const int LOGON32_LOGON_INTERACTIVE = 2; public const int LOGON32_PROVIDER_DEFAULT = 0; [DllImport("advapi32.dll")] public static extern int LogonUserA(String lpszUserName, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] public static extern int DuplicateToken(IntPtr hToken, int impersonationLevel, ref IntPtr hNewToken); [DllImport("advapi32.dll", CharSet=CharSet.Auto, SetLastError=true)] public static extern bool RevertToSelf(); [DllImport("kernel32.dll", CharSet=CharSet.Auto)] public static extern bool CloseHandle(IntPtr handle); #endregion public Impersonation() { } #region SampleUsage public void SampleCallingMethod(Object s, EventArgs e) { if(ImpersonateUser("username", "domain", "password")) { //Insert your code that runs under the security context of a specific user here. UnImpersonation(); } else { //Your impersonation failed. Therefore, include a fail-safe mechanism here. } } #endregion public bool ImpersonateUser(String userName, String domain, String password) { WindowsIdentity tempWindowsIdentity; IntPtr token = IntPtr.Zero; IntPtr tokenDuplicate = IntPtr.Zero; if(RevertToSelf()) { if(LogonUserA(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(); if (impersonationContext != null) { CloseHandle(token); CloseHandle(tokenDuplicate); return true; } } } } if(token!= IntPtr.Zero) CloseHandle(token); if(tokenDuplicate!=IntPtr.Zero) CloseHandle(tokenDuplicate); return false; } public void UnImpersonation() { impersonationContext.Undo(); } } }