使用HttpClient的HTTPS请求失败

问题描述

我正在使用以下代码并获得 HttpRequestException 异常：

I am using the following code and get HttpRequestException exception:

using (var handler = new HttpClientHandler())
{
    handler.ClientCertificateOptions = ClientCertificateOption.Manual;
    handler.SslProtocols = SslProtocols.Tls12;
    handler.ClientCertificates.Add(new X509Certificate2(@"C:\certificates\cert.pfx"));

    // I also tried to add another certificates that was provided to https access
    // by administrators of the site, but it still doesn't work.
    //handler.ClientCertificates.Add(new X509Certificate2(@"C:\certificates\cert.crt"));
    //handler.ClientCertificates.Add(new X509Certificate2(@"C:\certificates\cert_ca.crt"));

    using (var client = new HttpClient(handler))
    {
        var response = client.GetAsync("https://someurl.com/api.php?arg1=some&arg2=test").GetAwaiter().GetResult();
        // ^ HttpRequestException: An error occurred while sending the request.
    }
}

例外：

WinHttpException: A security error occurred
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    System.Runtime.CompilerServices.ConfiguredTaskAwaitable+ConfiguredTaskAwaiter.GetResult()
    System.Net.Http.WinHttpHandler+<StartRequest>d__105.MoveNext()

HttpRequestException: An error occurred while sending the request.
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    System.Runtime.CompilerServices.ConfiguredTaskAwaitable+ConfiguredTaskAwaiter.GetResult()
    System.Net.Http.HttpClient+<FinishSendAsync>d__58.MoveNext()
    System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
    System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
    System.Runtime.CompilerServices.TaskAwaiter.GetResult()
    MyApp.Web.Controllers.HomeController.Test() in HomeController.cs
        var response = client.GetAsync("https://someurl.com/api.php?arg1=some&arg2=test").GetAwaiter().GetResult();
    lambda_method(Closure , object , Object[] )
    Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker+<InvokeActionMethodAsync>d__27.MoveNext()

我还尝试将相同的证书导出到Windows证书存储区，并通过Google Chrome使用它，它工作正常（浏览器要求我确认已安装的证书，然后加载资源）。

I also tried to export the same certificates to Windows Certificate Store and use it via Google Chrome and it works fine (browser asked me to confirm installed certificate and then loaded the resource).

为什么在我的代码中不起作用？

Why it's not working in my code?

已更新

我还尝试添加回调以验证证书：

I also tried to add callback to validate the certificate:

handler.ServerCertificateCustomValidationCallback = (message, certificate2, arg3, arg4) =>
{
    // I set a breakpoint to this point but it is not catched.
    return true;
};

UPDATED2

证书使用SHA-1。尼尔·莫斯（Neil Moss）在评论中提到。
如果是无法正常工作的真正原因，是否有解决方法？

The certificate is used SHA-1. Neil Moss is mentioned in the comments that support for SHA1 certs is being withdrawn.If it is the real reason why it is not working, is there workaround for it?

解决方案

谢谢尼尔·莫斯的解决方案。他建议对SSL协议使用Tls标志。

Thank you Neil Moss for solution. He proposed to use Tls flag for SSL protocol.

handler.SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls11 | SslProtocols.Tls;

但这还需要以下条件：

handler.ServerCertificateCustomValidationCallback = (message, cert, chain, errors) => true;

在我添加了此功能之后，它就可以正常工作。

After I added this one it works fine.

推荐答案

根据，您必须通过以下方式启用TLS1.2：

According to this SO post, you must enable TLS1.2 with ServicePointManager.

System.Net.ServicePointManager.SecurityProtocol =
    SecurityProtocolType.Tls12 |
    SecurityProtocolType.Tls11 |
    SecurityProtocolType.Tls; // comparable to modern browsers

对于ServicePointManager.SecurityProtocols属性进行了以下声明： / p>

Also noteworthy, the MSDN documentation for ServicePointManager.SecurityProtocols property makes this statement:

这表明可能存在某种形式的SHA1块 。

which suggests that some form of SHA1 block might be in place.

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