强制HttpClient信任单个证书

Question

你能强迫HttpClient只信任一个证书吗？

我知道你可以这样做:

WebRequestHandler handler = new WebRequestHandler();
X509Certificate2 certificate = GetMyX509Certificate();
handler.ClientCertificates.Add(certificate);
HttpClient client = new HttpClient(handler);

但是这会迫使它只信任单个证书,还是会信任证书和所有证书fx.GlobalSign可以验证吗？

基本上我想确保它只能是我的客户正在与之交谈的服务器/证书.

Answer 1

你能强迫HttpClient只信任一个证书吗？...基本上我想确保它只能是我的客户正在与之交谈的服务器/证书.

是.但什么类型的证书？服务器还是CA？以下两个例子.

此外,在服务器的情况下,固定公钥而不是证书可能更好.这是因为像谷歌这样的组织每30天左右轮换一次服务器证书,以保证移动客户端的CRL小.但是,组织将重新认证相同的公钥.

以下是将CA用于特定CA以进行SSL连接的固定CA的示例.它并不需要放置证书的证书存储.您可以在应用中携带CA.

static bool VerifyServerCertificate(object sender, X509Certificate certificate,
    X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
    try
    {
        String CA_FILE = "ca-cert.der";
        X509Certificate2 ca = new X509Certificate2(CA_FILE);

        X509Chain chain2 = new X509Chain();
        chain2.ChainPolicy.ExtraStore.Add(ca);

        // Check all properties (NoFlag is correct)
        chain2.ChainPolicy.VerificationFlags = X509VerificationFlags.NoFlag;

        // This setup does not have revocation information
        chain2.ChainPolicy.RevocationMode = X509RevocationMode.NoCheck;

        // Build the chain
        chain2.Build(new X509Certificate2(certificate));

        // Are there any failures from building the chain?
        if (chain2.ChainStatus.Length == 0)
            return false;

        // If there is a status, verify the status is NoError
        bool result = chain2.ChainStatus[0].Status == X509ChainStatusFlags.NoError;
        Debug.Assert(result == true);

        return result;
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex);
    }

    return false;
}

我没有想出如何chain2默认使用这个链(上面),这样就不需要回调了.也就是说,将它安装在ssl套接字上,连接将"正常工作".

而且我还没弄清楚如何安装它以便它传递给回调.也就是说,我必须为每次调用回调构建链,因为我chain2没有传递给函数chain.

以下是从OWASP的证书和公钥固定中固定服务器证书的示例.它并不需要放置证书的证书存储.您可以在应用中携带证书或公钥.

// Encoded RSAPublicKey
private static String PUB_KEY = "30818902818100C4A06B7B52F8D17DC1CCB47362" +
    "C64AB799AAE19E245A7559E9CEEC7D8AA4DF07CB0B21FDFD763C63A313A668FE9D764E" +
    "D913C51A676788DB62AF624F422C2F112C1316922AA5D37823CD9F43D1FC54513D14B2" +
    "9E36991F08A042C42EAAEEE5FE8E2CB10167174A359CEBF6FACC2C9CA933AD403137EE" +
    "2C3F4CBED9460129C72B0203010001";

public static void Main(string[] args)
{
  ServicePointManager.ServerCertificateValidationCallback = PinPublicKey;
  WebRequest wr = WebRequest.Create("https://encrypted.google.com/");
  wr.GetResponse();
}

public static bool PinPublicKey(object sender, X509Certificate certificate, X509Chain chain,
                                SslPolicyErrors sslPolicyErrors)
{
  if (null == certificate)
    return false;

  String pk = certificate.GetPublicKeyString();
  if (pk.Equals(PUB_KEY))
    return true;

  // Bad dog
  return false;
}