Windows Authentication

[RobDog888]

I'm finally getting around to ASP.NET authentication for a page and its not validating for some reason.

Here is my code (ASP.NET 1.1).

Option Explicit On 
 
Imports System.Security.Principal
Imports System.Runtime.InteropServices
 
Public Class index3
 
    Inherits System.Web.UI.Page
 
    Declare Function LogonUserA Lib "advapi32.dll" (ByVal lpszUsername As String, ByVal lpszDomain As String, ByVal lpszPassword As String, ByVal dwLogonType As Integer, ByVal dwLogonProvider As Integer, ByRef phToken As IntPtr) As Integer
    Declare Auto Function DuplicateToken Lib "advapi32.dll" (ByVal ExistingTokenHandle As IntPtr, ByVal ImpersonationLevel As Integer, ByRef DuplicateTokenHandle As IntPtr) As Integer
    Declare Auto Function RevertToSelf Lib "advapi32.dll" () As Long
    Declare Auto Function CloseHandle Lib "kernel32.dll" (ByVal handle As IntPtr) As Long
 
    Private LOGON32_LOGON_INTERACTIVE As Integer = 2
    Private LOGON32_PROVIDER_DEFAULT As Integer = 0
 
    Private impersonationContext As WindowsImpersonationContext
 
    Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
        'Me.txtUsername.Text = "Domain\Username"
        'Me.txtPassword.Text = String.Empty
    End Sub
 
    Private Sub btnLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLogin.Click
        If impersonateValidUser(Me.txtUsername.Text, Me.txtPassword.Text) Then
            'MessageBox.Show("User authenticated sucessfully")
            'Insert your code that runs under the security context of a specific user here.
            Response.Redirect("index2.aspx")
            undoImpersonation()
        Else
            'MessageBox.Show("Invalid password or user")
            'Your impersonation failed. Therefore, include a fail-safe mechanism here.
            Response.Redirect("index.aspx")
        End If
    End Sub
 
    Private Function impersonateValidUser(ByVal userName As String, ByVal password As String) As Boolean
 
        Dim tempWindowsIdentity As WindowsIdentity
        Dim token As IntPtr = IntPtr.Zero
        Dim tokenDuplicate As IntPtr = IntPtr.Zero
        Dim ar() As String
        Dim domain As String
        impersonateValidUser = False
        ar = userName.Split("\")
        If UBound(ar) = 0 Then
            CloseHandle(token)
            Exit Function
        Else
            domain = ar(0)
            userName = ar(1)
        End If
        If RevertToSelf() Then
            If LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, token) <> 0 Then
                If DuplicateToken(token, 2, tokenDuplicate) <> 0 Then
                    tempWindowsIdentity = New WindowsIdentity(tokenDuplicate)
                    impersonationContext = tempWindowsIdentity.Impersonate()
                    If Not impersonationContext Is Nothing Then
                        impersonateValidUser = True
                    End If
                End If
            End If
        End If
        If Not tokenDuplicate.Equals(IntPtr.Zero) Then
            CloseHandle(tokenDuplicate)
        End If
        If Not token.Equals(IntPtr.Zero) Then
            CloseHandle(token)
        End If
    End Function
 
    Private Sub undoImpersonation()
        impersonationContext.Undo()
    End Sub