WindowsImpersonationContext Klasse

Definition

Namespace:

System.Security.Principal

Assembly:

mscorlib.dll

Stellt den Windows-Benutzer vor dem Identitätswechsel dar.

public ref class WindowsImpersonationContext : IDisposable

[System.Runtime.InteropServices.ComVisible(true)]
public class WindowsImpersonationContext : IDisposable

[<System.Runtime.InteropServices.ComVisible(true)>]
type WindowsImpersonationContext = class
    interface IDisposable

Public Class WindowsImpersonationContext
Implements IDisposable

Vererbung

Object

WindowsImpersonationContext

Attribute

ComVisibleAttribute

Implementiert

IDisposable

Beispiele

Im folgenden Beispiel wird veranschaulicht, wie Sie die Identität eines Benutzers annehmen und dann zur ursprünglichen Identität wiederherstellen.

// This sample demonstrates the use of the WindowsIdentity class to impersonate a user.
// IMPORTANT NOTES: 
// 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.
// On Windows Vista and later this sample must be run as an administrator. 

#using <System.dll>

using namespace System;
using namespace System::Runtime::InteropServices;
using namespace System::Security::Principal;
using namespace System::Security::Permissions;


[DllImport("advapi32.dll",SetLastError=true)]
bool LogonUser( String^ lpszUsername, String^ lpszDomain, String^ lpszPassword, int dwLogonType, int dwLogonProvider, IntPtr * phToken );

[DllImport("kernel32.dll",CharSet=CharSet::Auto)]
bool CloseHandle( IntPtr handle );

// Test harness.
// If you incorporate this code into a DLL, be sure to demand FullTrust.

[PermissionSetAttribute(SecurityAction::Demand,Name="FullTrust")]
int main()
{
   IntPtr tokenHandle = IntPtr(0);

   try
   {
      String^ userName;
      String^ domainName;
      
      // 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 the 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 int LOGON32_PROVIDER_DEFAULT = 0;
      
      //This parameter causes LogonUser to create a primary token.
      const int LOGON32_LOGON_INTERACTIVE = 2;
      const int SecurityImpersonation = 2;
      tokenHandle = IntPtr::Zero;
      
      // Call LogonUser to obtain a handle to an access token.
      bool returnValue = LogonUser( userName, domainName, Console::ReadLine(), LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT,  &tokenHandle );
      Console::WriteLine( "LogonUser called." );
      if ( false == returnValue )
      {
         int ret = Marshal::GetLastWin32Error();
         Console::WriteLine( "LogonUser failed with error code : {0}", ret );
         throw gcnew System::ComponentModel::Win32Exception( ret );
      }
      Console::WriteLine( "Did LogonUser Succeed? {0}", (returnValue ? (String^)"Yes" : "No") );
      Console::WriteLine( "Value of Windows NT token: {0}", tokenHandle );
      
      // Check the identity.
      Console::WriteLine( "Before impersonation: {0}", WindowsIdentity::GetCurrent()->Name );
      
      // The token that is passed to the following constructor must 
      // be a primary token in order to use it for impersonation.
      WindowsIdentity^ newId = gcnew WindowsIdentity( tokenHandle );
      WindowsImpersonationContext^ impersonatedUser = newId->Impersonate();
      
      // Check the identity.
      Console::WriteLine( "After impersonation: {0}", WindowsIdentity::GetCurrent()->Name );
      
      // Stop impersonating the user.
      impersonatedUser->Undo();
      
      // Check the identity.
      Console::WriteLine( "After Undo: {0}", WindowsIdentity::GetCurrent()->Name );
      
      // Free the tokens.
      if ( tokenHandle != IntPtr::Zero )
            CloseHandle( tokenHandle );
   }
   catch ( Exception^ ex ) 
   {
      Console::WriteLine( "Exception occurred. {0}", ex->Message );
   }

}

// This sample demonstrates the use of the WindowsIdentity class to impersonate a user.
// IMPORTANT NOTES:
// 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.
// On Windows Vista and later this sample must be run as an administrator.

using System;
using System.Runtime.InteropServices;
using System.Security.Principal;
using System.Security.Permissions;
using Microsoft.Win32.SafeHandles;
using System.Runtime.ConstrainedExecution;
using System.Security;

public class ImpersonationDemo
{
    [DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword,
        int dwLogonType, int dwLogonProvider, out SafeTokenHandle phToken);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
    public extern static bool CloseHandle(IntPtr handle);

    // Test harness.
    // If you incorporate this code into a DLL, be sure to demand FullTrust.
    [PermissionSetAttribute(SecurityAction.Demand, Name = "FullTrust")]
    public static void Main(string[] args)
    {
        SafeTokenHandle safeTokenHandle;
        try
        {
            string userName, domainName;
            // 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 the 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 int LOGON32_PROVIDER_DEFAULT = 0;
            //This parameter causes LogonUser to create a primary token.
            const int LOGON32_LOGON_INTERACTIVE = 2;

            // Call LogonUser to obtain a handle to an access token.
            bool returnValue = LogonUser(userName, domainName, Console.ReadLine(),
                LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT,
                out safeTokenHandle);

            Console.WriteLine("LogonUser called.");

            if (false == returnValue)
            {
                int ret = Marshal.GetLastWin32Error();
                Console.WriteLine("LogonUser failed with error code : {0}", ret);
                throw new System.ComponentModel.Win32Exception(ret);
            }
            using (safeTokenHandle)
            {
                Console.WriteLine("Did LogonUser Succeed? " + (returnValue ? "Yes" : "No"));
                Console.WriteLine("Value of Windows NT token: " + safeTokenHandle);

                // Check the identity.
                Console.WriteLine("Before impersonation: "
                    + WindowsIdentity.GetCurrent().Name);
                // Use the token handle returned by LogonUser.
                using (WindowsIdentity newId = new WindowsIdentity(safeTokenHandle.DangerousGetHandle()))
                {
                    using (WindowsImpersonationContext impersonatedUser = newId.Impersonate())
                    {

                        // Check the identity.
                        Console.WriteLine("After impersonation: "
                            + WindowsIdentity.GetCurrent().Name);
                    }
                }
                // Releasing the context object stops the impersonation
                // Check the identity.
                Console.WriteLine("After closing the context: " + WindowsIdentity.GetCurrent().Name);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine("Exception occurred. " + ex.Message);
        }
    }
}
public sealed class SafeTokenHandle : SafeHandleZeroOrMinusOneIsInvalid
{
    private SafeTokenHandle()
        : base(true)
    {
    }

    [DllImport("kernel32.dll")]
    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
    [SuppressUnmanagedCodeSecurity]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool CloseHandle(IntPtr handle);

    protected override bool ReleaseHandle()
    {
        return CloseHandle(handle);
    }
}

' This sample demonstrates the use of the WindowsIdentity class to impersonate a user.
' IMPORTANT NOTES: 
' 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.
' On Windows Vista and later this sample must be run as an administrator. 

Imports System.Runtime.InteropServices
Imports System.Security.Principal
Imports System.Security.Permissions
Imports Microsoft.Win32.SafeHandles
Imports System.Runtime.ConstrainedExecution
Imports System.Security

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

        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, _
            <Out()> ByRef phToken As SafeTokenHandle) As Boolean

        Public Declare Auto Function CloseHandle Lib "kernel32.dll" (ByVal handle As IntPtr) As Boolean

        ' Test harness.
        ' If you incorporate this code into a DLL, be sure to demand FullTrust.
        <PermissionSetAttribute(SecurityAction.Demand, Name:="FullTrust")> _
        Public Overloads Shared Sub Main(ByVal args() As String)
            Dim safeTokenHandle As SafeTokenHandle = Nothing
            Dim tokenHandle 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

                ' 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, safeTokenHandle)

                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
                Using safeTokenHandle
                    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: " + safeTokenHandle.DangerousGetHandle().ToString()))

                    ' Check the identity.
                    Console.WriteLine(("Before impersonation: " + WindowsIdentity.GetCurrent().Name))

                    ' Use the token handle returned by LogonUser.
                    Using newId As New WindowsIdentity(safeTokenHandle.DangerousGetHandle())
                        Using impersonatedUser As WindowsImpersonationContext = newId.Impersonate()

                            ' Check the identity.
                            Console.WriteLine(("After impersonation: " + WindowsIdentity.GetCurrent().Name))

                            ' Free the tokens.
                        End Using
                    End Using
                End Using
            Catch ex As Exception
                Console.WriteLine(("Exception occurred. " + ex.Message))
            End Try
        End Sub
    End Class
End Module

Public NotInheritable Class SafeTokenHandle
    Inherits SafeHandleZeroOrMinusOneIsInvalid

    Private Sub New()
        MyBase.New(True)

    End Sub

    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
    <DllImport("kernel32.dll"), ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success), SuppressUnmanagedCodeSecurity()> _
    Private Shared Function CloseHandle(ByVal handle As IntPtr) As <MarshalAs(UnmanagedType.Bool)> Boolean

    End Function
    Protected Overrides Function ReleaseHandle() As Boolean
        Return CloseHandle(handle)

    End Function 'ReleaseHandle
End Class

Hinweise

Diese Klasse stellt die Identität eines Benutzers zurück, nachdem der Benutzer die Identität eines anderen Benutzers angenommen hat.

Wichtig

Dieser Typ implementiert die IDisposable-Schnittstelle. Nach Abschluss der Verwendung sollten Sie den Typ entweder direkt oder indirekt löschen. Zum direkten Löschen des Typs rufen Sie seine Dispose-Methode in einem try/catch-Block auf. Zum indirekten Löschen verwenden Sie ein Sprachkonstrukt wie using (in C#) oder Using (in Visual Basic). Weitere Informationen finden Sie im Abschnitt „Verwenden eines Objekts, das IDisposable implementiert“ des Themas „Die IDisposable-Schnittstelle“.

Methoden

Dispose()	Gibt alle vom WindowsImpersonationContext verwendeten Ressourcen frei.
Dispose(Boolean)	Gibt die von WindowsImpersonationContext verwendeten nicht verwalteten Ressourcen und optional die verwalteten Ressourcen frei.
Equals(Object)	Bestimmt, ob das angegebene Objekt gleich dem aktuellen Objekt ist. (Geerbt von Object)
GetHashCode()	Fungiert als Standardhashfunktion. (Geerbt von Object)
GetType()	Ruft den Type der aktuellen Instanz ab. (Geerbt von Object)
MemberwiseClone()	Erstellt eine flache Kopie des aktuellen Object. (Geerbt von Object)
ToString()	Gibt eine Zeichenfolge zurück, die das aktuelle Objekt darstellt. (Geerbt von Object)
Undo()	Setzt den Benutzerkontext auf den Windows-Benutzer zurück, der durch dieses Objekt dargestellt wird.