RemoteCertificateValidationCallback 代理人

定義

命名空間:

System.Net.Security

組件:

System.Net.Security.dll

驗證用於驗證的遠端 Secure Sockets Layer (SSL) 憑證。

public delegate bool RemoteCertificateValidationCallback(System::Object ^ sender, X509Certificate ^ certificate, X509Chain ^ chain, SslPolicyErrors sslPolicyErrors);

public delegate bool RemoteCertificateValidationCallback(object sender, X509Certificate? certificate, X509Chain? chain, SslPolicyErrors sslPolicyErrors);

type RemoteCertificateValidationCallback = delegate of obj * X509Certificate * X509Chain * SslPolicyErrors -> bool

Public Delegate Function RemoteCertificateValidationCallback(sender As Object, certificate As X509Certificate, chain As X509Chain, sslPolicyErrors As SslPolicyErrors) As Boolean 

參數

sender

Object

物件，包含這個驗證的狀態資訊。

certificate

X509Certificate

憑證，用於驗證遠端群體。

chain

X509Chain

憑證授權單位的鏈結，與遠端憑證相關聯。

sslPolicyErrors

SslPolicyErrors

一或多個錯誤，與遠端憑證相關聯。

傳回值

Boolean

Boolean 值，決定是否接受指定的憑證用於驗證。

範例

下列程式代碼範例會實作 類別實例 RemoteCertificateValidationCallback 叫用的方法。 如果發生驗證錯誤，這個方法會顯示並傳回 false，以防止與未經驗證的伺服器進行通訊。

    // Load a table of errors that might cause 
    // the certificate authentication to fail.
    static void InitializeCertificateErrors()
    {
        certificateErrors->Add(0x800B0101,
            "The certification has expired.");
        certificateErrors->Add(0x800B0104,
            "A path length constraint "
            "in the certification chain has been violated.");
        certificateErrors->Add(0x800B0105,
            "A certificate contains an unknown extension "
            "that is marked critical.");
        certificateErrors->Add(0x800B0107,
            "A parent of a given certificate in fact "
            "did not issue that child certificate.");
        certificateErrors->Add(0x800B0108,
            "A certificate is missing or has an empty value "
            "for a necessary field.");
        certificateErrors->Add(0x800B0109,
            "The certificate root is not trusted.");
        certificateErrors->Add(0x800B010C,
            "The certificate has been revoked.");
        certificateErrors->Add(0x800B010F,
            "The name in the certificate does not not match "
            "the host name requested by the client.");
        certificateErrors->Add(0x800B0111,
            "The certificate was explicitly marked "
            "as untrusted by the user.");
        certificateErrors->Add(0x800B0112,
            "A certification chain processed correctly, "
            "but one of the CA certificates is not trusted.");
        certificateErrors->Add(0x800B0113,
            "The certificate has an invalid policy.");
        certificateErrors->Add(0x800B0114,
            "The certificate name is either not "
            "in the permitted list or is explicitly excluded.");
        certificateErrors->Add(0x80092012,
            "The revocation function was unable to check "
            "revocation for the certificate.");
        certificateErrors->Add(0x80090327,
            "An unknown error occurred while "
            "processing the certificate.");
        certificateErrors->Add(0x80096001,
            "A system-level error occurred "
            "while verifying trust.");
        certificateErrors->Add(0x80096002,
            "The certificate for the signer of the message "
            "is invalid or not found.");
        certificateErrors->Add(0x80096003,
            "One of the counter signatures was invalid.");
        certificateErrors->Add(0x80096004,
            "The signature of the certificate "
            "cannot be verified.");
        certificateErrors->Add(0x80096005,
            "The time stamp signature or certificate "
            "could not be verified or is malformed.");
        certificateErrors->Add(0x80096010,
            "The digital signature of the object "
            "was not verified.");
        certificateErrors->Add(0x80096019,
            "The basic constraint extension of a certificate "
            "has not been observed.");
    }

    static String^ CertificateErrorDescription(UInt32 problem)
    {
        // Initialize the error message dictionary 
        // if it is not yet available.
        if (certificateErrors->Count == 0)
        {
            InitializeCertificateErrors();
        }

        String^ description = safe_cast<String^>(
            certificateErrors[problem]);
        if (description == nullptr)
        {
            description = String::Format(
                CultureInfo::CurrentCulture,
                "Unknown certificate error - 0x{0:x8}",
                problem);
        }

        return description;
    }

public:
    // The following method is invoked 
    // by the CertificateValidationDelegate.
static bool ValidateServerCertificate(
        Object^ sender,
        X509Certificate^ certificate,
        X509Chain^ chain,
        SslPolicyErrors sslPolicyErrors)
    {
    
        Console::WriteLine("Validating the server certificate.");
        if (sslPolicyErrors == SslPolicyErrors::None)
            return true;

        Console::WriteLine("Certificate error: {0}", sslPolicyErrors);

        // Do not allow this client to communicate with unauthenticated servers.
        return false;
    }

// The following method is invoked by the RemoteCertificateValidationDelegate.
public static bool ValidateServerCertificate(
      object sender,
      X509Certificate certificate,
      X509Chain chain,
      SslPolicyErrors sslPolicyErrors)
{
   if (sslPolicyErrors == SslPolicyErrors.None)
        return true;

    Console.WriteLine("Certificate error: {0}", sslPolicyErrors);

    // Do not allow this client to communicate with unauthenticated servers.
    return false;
}

下列程式代碼範例會使用上述程式碼範例中定義的方法來建立委派。

// Create a TCP/IP client socket.
// machineName is the host running the server application.
TcpClient^ client = gcnew TcpClient(machineName, 5000);
Console::WriteLine("Client connected.");
  
// Create an SSL stream that will close 
// the client's stream.
SslStream^ sslStream = gcnew SslStream(
    client->GetStream(), false,
    gcnew RemoteCertificateValidationCallback(ValidateServerCertificate),
    nullptr);
  
// The server name must match the name
// on the server certificate.
try
{
    sslStream->AuthenticateAsClient(serverName);
}
catch (AuthenticationException^ ex) 
{
    Console::WriteLine("Exception: {0}", ex->Message);
    if (ex->InnerException != nullptr)
    {
        Console::WriteLine("Inner exception: {0}", 
            ex->InnerException->Message);
    }

    Console::WriteLine("Authentication failed - "
        "closing the connection.");
    sslStream->Close();
    client->Close();
    return;
}

// Create a TCP/IP client socket.
// machineName is the host running the server application.
TcpClient client = new TcpClient(machineName,5000);
Console.WriteLine("Client connected.");
// Create an SSL stream that will close the client's stream.
SslStream sslStream = new SslStream(
    client.GetStream(),
    false,
    new RemoteCertificateValidationCallback (ValidateServerCertificate),
    null
    );
// The server name must match the name on the server certificate.
try
{
    sslStream.AuthenticateAsClient(serverName);
}
catch (AuthenticationException e)
{
    Console.WriteLine("Exception: {0}", e.Message);
    if (e.InnerException != null)
    {
        Console.WriteLine("Inner exception: {0}", e.InnerException.Message);
    }
    Console.WriteLine ("Authentication failed - closing the connection.");
    client.Close();
    return;
}

備註

委派的 sslPolicyErrors 自變數包含驗證客戶端或伺服器時，SSPI 傳回的任何憑證錯誤。 Boolean由這個委派叫用之 方法所傳回的值會決定是否允許驗證成功。

此委派會與類別搭配 SslStream 使用。

擴充方法

GetMethodInfo(Delegate)

取得表示特定委派所代表之方法的物件。

另請參閱

• LocalCertificateSelectionCallback