Marshal.ZeroFreeCoTaskMemAnsi(IntPtr) Método

Definição

Libera um ponteiro de cadeia de caracteres não gerenciado alocado usando o 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)

Parâmetros

s
IntPtr

O endereço da cadeia de caracteres não gerenciada a liberar.The address of the unmanaged string to free.

Atributos

Exemplos

O exemplo a seguir usa o método SecureStringToCoTaskMemAnsi para realizar marshaling e descriptografar o conteúdo de um objeto SecureString para um bloco de memória não gerenciada.The following example uses the SecureStringToCoTaskMemAnsi method to marshal and decrypt the contents of a SecureString object to a block of unmanaged memory. Em seguida, ele usa o método ZeroFreeCoTaskMemAnsi para zerar e descartar o bloco não gerenciado.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

Comentários

O método ZeroFreeCoTaskMemAnsi primeiro zera e libera a memória não gerenciada que foi alocada usando o método SecureStringToCoTaskMemAnsi.The ZeroFreeCoTaskMemAnsi method first zeros out and then frees unmanaged memory that was allocated using the SecureStringToCoTaskMemAnsi method.

Segurança

SecurityCriticalAttribute
requer confiança total para o chamador imediato.requires full trust for the immediate caller. Este membro não pode ser usado pelo código transparente ou parcialmente confiável.This member cannot be used by partially trusted or transparent code.

Aplica-se a