Marshal.ZeroFreeCoTaskMemAnsi(IntPtr) Método

Definición

Libera un puntero a una cadena no administrada que se ha asignado con el método SecureStringToCoTaskMemAnsi(SecureString).Frees an unmanaged string pointer that was allocated using the SecureStringToCoTaskMemAnsi(SecureString) method.

public:
 static void ZeroFreeCoTaskMemAnsi(IntPtr s);
[System.Security.SecurityCritical]
public static void ZeroFreeCoTaskMemAnsi (IntPtr s);
static member ZeroFreeCoTaskMemAnsi : nativeint -> unit
Public Shared Sub ZeroFreeCoTaskMemAnsi (s As IntPtr)

Parámetros

s
IntPtr

La dirección de la cadena no administrada que se va a liberar.The address of the unmanaged string to free.

Atributos

Ejemplos

En el ejemplo siguiente se usa el método SecureStringToCoTaskMemAnsi para calcular las referencias y descifrar el contenido de un objeto SecureString en un bloque de memoria no administrada.The following example uses the SecureStringToCoTaskMemAnsi method to marshal and decrypt the contents of a SecureString object to a block of unmanaged memory. A continuación, usa el método ZeroFreeCoTaskMemAnsi para desechar el bloque no administrado.It then uses the ZeroFreeCoTaskMemAnsi method to zero out and dispose the unmanaged block.

using System;
using System.Runtime.InteropServices;
using System.Security;

class MarshalExample
{
     static void Main()
     {
         IntPtr unmanagedRef = IntPtr.Zero;

          // Ask the user for a password.
          Console.Write("Please enter your password: ");

          SecureString passWord = GetPassword();

          Console.WriteLine("Copying and decrypting the string to unmanaged memory...");

          // Copy the Secure string to unmanaged memory (and decrypt it).
          unmanagedRef = Marshal.SecureStringToCoTaskMemAnsi(passWord);

          if (unmanagedRef != IntPtr.Zero)
          {
              Console.WriteLine("Zeroing out unmanaged memory...");

              Marshal.ZeroFreeCoTaskMemAnsi(unmanagedRef);
          }
          passWord.Dispose();
          
         Console.WriteLine("Done.");
     }

     public static SecureString GetPassword()
     {
         SecureString password = new SecureString();

         // get the first character of the password
         ConsoleKeyInfo nextKey = Console.ReadKey(true);

         while (nextKey.Key != ConsoleKey.Enter)
         {
             if (nextKey.Key == ConsoleKey.Backspace)
             {
                 if (password.Length > 0)
                 {
                     password.RemoveAt(password.Length - 1);

                     // erase the last * as well
                     Console.Write(nextKey.KeyChar);
                     Console.Write(" ");
                     Console.Write(nextKey.KeyChar);
                 }
             }
             else
             {
                 password.AppendChar(nextKey.KeyChar);
                 Console.Write("*");
             }

             nextKey = Console.ReadKey(true);
         }

         Console.WriteLine();

         // lock the password down
         password.MakeReadOnly();
         return password;
     }
}
Imports System.Runtime.InteropServices
Imports System.Security

Module Example
    Sub Main()
        Dim unmanagedRef As IntPtr

         ' Ask the user for a password.
         Console.Write("Please enter your password: ")
         Dim passWord As SecureString = GetPassword()

         Console.WriteLine("Copying and decrypting the string to unmanaged memory...")

         ' Copy the Secure string to unmanaged memory (and decrypt it).
         unmanagedRef = Marshal.SecureStringToCoTaskMemAnsi(passWord)

         If unmanagedRef <> IntPtr.Size Then
             Console.WriteLine("Zeroing out unmanaged memory...")
             Marshal.ZeroFreeCoTaskMemAnsi(unmanagedRef)
         End If
         passWord.Dispose()

        Console.WriteLine("Done.")
    End Sub



    Function GetPassword() As SecureString
        Dim password As New SecureString()

        ' get the first character of the password
        Dim nextKey As ConsoleKeyInfo = Console.ReadKey(True)

        While nextKey.Key <> ConsoleKey.Enter
            If nextKey.Key = ConsoleKey.BackSpace Then
                If password.Length > 0 Then
                    password.RemoveAt(password.Length - 1)

                    ' erase the last * as well
                    Console.Write(nextKey.KeyChar)
                    Console.Write(" ")
                    Console.Write(nextKey.KeyChar)
                End If
            Else
                password.AppendChar(nextKey.KeyChar)
                Console.Write("*")
            End If

            nextKey = Console.ReadKey(True)
        End While

        Console.WriteLine()

        ' lock the password down
        password.MakeReadOnly()
        Return password

    End Function
End Module

Comentarios

El método ZeroFreeCoTaskMemAnsi primero pone a cero y libera la memoria no administrada que se asignó mediante el método SecureStringToCoTaskMemAnsi.The ZeroFreeCoTaskMemAnsi method first zeros out and then frees unmanaged memory that was allocated using the SecureStringToCoTaskMemAnsi method.

Seguridad

SecurityCriticalAttribute
Requiere plena confianza para el llamador inmediato.requires full trust for the immediate caller. Este miembro no puede ser utilizado por código transparente o de confianza parcial.This member cannot be used by partially trusted or transparent code.

Se aplica a