c# - .net Core X Forwarded Proto 不工作

Question

我正在努力让我的 .net core 1.1 应用程序在负载均衡器后面工作并强制执行 https。我的 Startup.cs 中有以下设置

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IServiceProvider serviceProvider, IOptions<Auth0Settings> auth0Settings)
{
    loggerFactory.AddConsole(Configuration.GetSection("Logging"));
    loggerFactory.AddDebug();


    var startupLogger = loggerFactory.CreateLogger<Startup>();


    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
        app.UseDatabaseErrorPage();
        app.UseBrowserLink();
        startupLogger.LogInformation("In Development");
    }
    else
    {
        startupLogger.LogInformation("NOT in development");
        app.UseExceptionHandler("/Home/Error");
    }

    app.UseMiddleware<HttpsRedirectMiddleware>();
    app.UseForwardedHeaders(new ForwardedHeadersOptions
    {
        ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
    });`
        app.UseCookieAuthentication(new CookieAuthenticationOptions
        {
            AuthenticationScheme= CookieAuthenticationDefaults.AuthenticationScheme,
            AutomaticAuthenticate = true,
            AutomaticChallenge = true,
            CookieHttpOnly = true,
            SlidingExpiration = true
        });

HttpsRedirectMiddleware 用于验证 LB 是否设置了 X-Forwarded-Proto，它确实设置了，并且以 https 作为唯一值返回。当我访问网站 (https://myapp.somedomain.net) 时，它知道我没有通过身份验证并将我重定向到 (http://myapp.somedomain.net/Account/Logon?ReturnUrl=%2f)。它失去了 SSL 连接并切换回我的端口 80。 .net 核心文档说要像下面这样使用“UseForwardedHeaders”，这在我的情况下不起作用。发生此切换时，控制台记录器没有来自中间件的任何错误或警告。

为了短期修复，我将其放在“UseForwardedHeaders”下方

    app.Use(async (context, next) =>
    {
        var xproto = context.Request.Headers["X-Forwarded-Proto"].ToString();
        if (xproto!=null && xproto.StartsWith("https", StringComparison.OrdinalIgnoreCase)){
            startupLogger.LogInformation("Switched to https");
            context.Request.Scheme = "https";
        }
        await next();

    });

上面的工作很完美，但是是一个 hack。我想以正确的方式去做。

Answer 1

.NET Core 有一个用于转发 header 的默认设置。对于 IIS 集成，它默认为 127.0.0.1。

追踪源代码后，我发现您可以清除KnownNetworks 和KnownProxies 列表以接受任何转发的请求。但是，最好仍然设置防火墙或将已知网络锁定到私有(private)子网。

var forwardingOptions = new ForwardedHeadersOptions()
{
    ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto
};
forwardingOptions.KnownNetworks.Clear(); // Loopback by default, this should be temporary
forwardingOptions.KnownProxies.Clear(); // Update to include

app.UseForwardedHeaders(forwardingOptions);

.NET Core 2.x 的

更新:记住在调试问题后设置代理/负载均衡器或专用网络的 IP。这可以防止绕过您的代理/负载平衡器并伪造 Forwarded-For header 。

services.Configure<ForwardedHeadersOptions>(options =>
{
    options.ForwardLimit = 2;

    // Replace with IP of your proxy/load balancer
    options.KnownProxies.Add(IPAddress.Parse("192.168.1.5"));

    // 192.168.1.0/24 allows any from 192.168.1.1-254;
    options.KnownNetworks.Add(new IPNetwork(IPAddress.Parse("192.168.1.0"), 24));
});

https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/proxy-load-balancer?view=aspnetcore-2.2#forwarded-headers-middleware-options