WindowsIdentity.Impersonate 方法 (IntPtr) (System.Security.Principal)

‘ This sample demonstrates the use of the WindowsIdentity class to impersonate a user. ‘ IMPORTANT NOTES: ‘ This sample can be run only on Windows XP. The default Windows 2000 security policy ‘ prevents this sample from executing properly, and changing the policy to allow ‘ proper execution presents a security risk. ‘ This sample requests the user to enter a password on the console screen. ‘ Because the console window does not support methods allowing the password to be masked, ‘ it will be visible to anyone viewing the screen. ‘ The sample is intended to be executed in a .NET Framework 1.1 environment. To execute ‘ this code in a 1.0 environment you will need to use a duplicate token in the call to the ‘ WindowsIdentity constructor. See KB article Q319615 for more information. Imports System Imports System.Runtime.InteropServices Imports System.Security.Principal Imports System.Security.Permissions Imports Microsoft.VisualBasic Module Module1 Public Class ImpersonationDemo Private Declare Auto Function LogonUser 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 Boolean _ Public Shared Function FormatMessage(ByVal dwFlags As Integer, ByRef lpSource As IntPtr, _ ByVal dwMessageId As Integer, ByVal dwLanguageId As Integer, ByRef lpBuffer As [String], _ ByVal nSize As Integer, ByRef Arguments As IntPtr) As Integer End Function Public Declare Auto Function CloseHandle Lib “kernel32.dll" (ByVal handle As IntPtr) As Boolean Public Declare Auto Function DuplicateToken Lib “advapi32.dll" (ByVal ExistingTokenHandle As IntPtr, _ ByVal SECURITY_IMPERSONATION_LEVEL As Integer, _ ByRef DuplicateTokenHandle As IntPtr) As Boolean ‘ Test harness. ‘ If you incorporate this code into a DLL, be sure to demand FullTrust. _ Public Overloads Shared Sub Main(ByVal args() As String) Dim tokenHandle As New IntPtr(0) Dim dupeTokenHandle As New IntPtr(0) Try Dim userName, domainName As String ‘ Get the user token for the specified user, domain, and password using the ‘ unmanaged LogonUser method. ‘ The local machine name can be used for the domain name to impersonate a user on this machine. Console.Write(“Enter the name of a domain on which to log on: “) domainName = Console.ReadLine() Console.Write(“Enter the login of a user on {0} that you wish to impersonate: “, domainName) userName = Console.ReadLine() Console.Write(“Enter the password for {0}: “, userName) Const LOGON32_PROVIDER_DEFAULT As Integer = 0 ‘This parameter causes LogonUser to create a primary token. Const LOGON32_LOGON_INTERACTIVE As Integer = 2 tokenHandle = IntPtr.Zero ‘ Call LogonUser to obtain a handle to an access token. Dim returnValue As Boolean = LogonUser(userName, domainName, Console.ReadLine(), LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, tokenHandle) Console.WriteLine(“LogonUser called.") If False = returnValue Then Dim ret As Integer = Marshal.GetLastWin32Error() Console.WriteLine(“LogonUser failed with error code : {0}", ret) Throw New System.ComponentModel.Win32Exception(ret) Return End If Dim success As String If returnValue Then success = “Yes" Else success = “No" Console.WriteLine((“Did LogonUser succeed? " + success)) Console.WriteLine((“Value of Windows NT token: " + tokenHandle.ToString())) ‘ Check the identity. Console.WriteLine((“Before impersonation: " + WindowsIdentity.GetCurrent().Name)) ‘ Use the token handle returned by LogonUser. Dim newId As New WindowsIdentity(tokenHandle) Dim impersonatedUser As WindowsImpersonationContext = newId.Impersonate() ‘ Check the identity. Console.WriteLine((“After impersonation: " + WindowsIdentity.GetCurrent().Name)) ‘ Stop impersonating the user. impersonatedUser.Undo() ‘ Check the identity. Console.WriteLine((“After Undo: " + WindowsIdentity.GetCurrent().Name)) ‘ Free the tokens. If Not System.IntPtr.op_Equality(tokenHandle, IntPtr.Zero) Then CloseHandle(tokenHandle) End If Catch ex As Exception Console.WriteLine((“Exception occurred. " + ex.Message)) End Try End Sub ‘Main End Class ‘Class1 End Module