如何在自定义验证中调用默认 ServerCertificateValidationCallback？

Question

我想修改 .Net 的默认 ServerCertificateValidationCallback 以验证我公司的某些证书​​为真，但保留其他证书的默认验证。

我似乎无法这样做，因为默认的 ServerCertificateValidationCallback 值为 null。

ServicePointManager.ServerCertificateValidationCallback = 
(sender, certificate, chain, sslPolicyErrors) => 
 validCertificatesSerialNumbers.Contains(certificate.GetSerialNumberString()) ||    
 defaultlCallback.Invoke(sender, certificate, chain, sslPolicyErrors) //How do I set defaultCallback?
;

谢谢

Answer 1

从我在reference source 中可以看出，这就是回调发挥作用的地方：

if (ServicePointManager.ServerCertificateValidationCallback != null)
{
    useDefault = false;
    return ServicePointManager.ServerCertValidationCallback.
                               Invoke(m_Request,
                                      certificate,
                                      chain,
                                      sslPolicyErrors);
}

if (useDefault)
    return sslPolicyErrors == SslPolicyErrors.None;

这意味着验证已经执行并且要知道它是否通过你只需要检查sslPolicyErrors 参数。你会这样做：

ServicePointManager.ServerCertificateValidationCallback = 
(sender, certificate, chain, sslPolicyErrors) => 
validCertificatesSerialNumbers.Contains(certificate.GetSerialNumberString()) || (sslPolicyErrors == SslPolicyErrors.None);