BililiveRecorder/BililiveRecorder.Web/OpenAccessWarningMiddleware.cs

115 lines
5.3 KiB
C#

using System;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Net.Http.Headers;
namespace BililiveRecorder.Web
{
public class OpenAccessWarningMiddleware
{
private readonly RequestDelegate next;
public OpenAccessWarningMiddleware(RequestDelegate next)
{
this.next = next ?? throw new ArgumentNullException(nameof(next));
}
public Task InvokeAsync(HttpContext context)
{
if (context.RequestServices.GetService<BasicAuthCredential>() is not null)
{
// 启用了身份验证,不需要警告
return this.next(context);
}
if (sourceIpNotLan(context) || haveReverseProxyHeaders(context) || haveCustomHostValue(context))
{
context.Response.StatusCode = 412;
var accept = context.Request.Headers[HeaderNames.Accept].ToString();
if (accept.Contains("text/html"))
{
context.Response.ContentType = "text/html; charset=utf-8";
return context.Response.WriteAsync("<!DOCTYPE html><html><head><meta charset=\"utf-8\"><title>Access Denied</title></head>" +
"<body><h1>Access Denied</h1><p>Open access from the internet detected. Please enable basic authentication by setting the environment variables \"BREC_HTTP_BASIC_USER\" and \"BREC_HTTP_BASIC_PASS\", " +
"or disable this warning by setting the environment variable \"BREC_HTTP_OPEN_ACCESS\".</p>" +
"<p>检测到非局域网无密码访问。请设置使用环境变量 \"BREC_HTTP_BASIC_USER\" 和 \"BREC_HTTP_BASIC_PASS\" 设置用户名密码," +
"或如果你已经通过其他方法实现了访问控制(如只在内网开放)可以通过设置环境变量 \"BREC_HTTP_OPEN_ACCESS\" 为任意值来禁用此警告。暴露在互联网上无密码的录播姬存在安全风险。</p>" +
"<hr><p>录播姬 BililiveRecorder " + GitVersionInformation.FullSemVer + "</p></body></html>\n");
}
else
{
context.Response.ContentType = "text/plain; charset=utf-8";
return context.Response.WriteAsync("Access Denied.\nOpen access from the internet detected. Please enable " +
"basic authentication by setting the environment variables \"BREC_HTTP_BASIC_USER\" and \"BREC_HTTP_BASIC_PASS\", " +
"or disable this warning by setting the environment variable \"BREC_HTTP_OPEN_ACCESS\".\n" +
"检测到非局域网无密码访问。请设置使用环境变量 \"BREC_HTTP_BASIC_USER\" 和 \"BREC_HTTP_BASIC_PASS\" 设置用户名密码," +
"或如果你已经通过其他方法实现了访问控制(如只在内网开放)可以通过设置环境变量 \"BREC_HTTP_OPEN_ACCESS\" 为任意值来禁用此警告。暴露在互联网上无密码的录播姬存在安全风险。\n" +
"录播姬 BililiveRecorder " + GitVersionInformation.FullSemVer + "\n");
}
}
else
{
return this.next(context);
}
}
private static bool sourceIpNotLan(HttpContext context)
{
var ip = context.Connection.RemoteIpAddress;
if (ip is null) return true;
return !isLocalIpv4Address(ip) && !ip.IsIPv6LinkLocal && !ip.IsIPv6UniqueLocal;
}
private static bool isLocalIpv4Address(IPAddress ip)
{
if (ip.IsIPv4MappedToIPv6)
ip = ip.MapToIPv4();
if (ip.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
return false;
var bytes = ip.GetAddressBytes();
if (bytes.Length != 4)
return false;
switch (bytes[0])
{
case 10: // 10.0.0.0/8
return true;
case 127: // 127.0.0.0/8
return true;
case 172: // 172.16.0.0/12
return bytes[1] >= 16 && bytes[1] <= 31;
case 192: // 192.168.0.0/16
return bytes[1] == 168;
default:
return false;
}
}
private static bool haveReverseProxyHeaders(HttpContext context)
{
return
context.Request.Headers.ContainsKey("X-Real-IP") ||
context.Request.Headers.ContainsKey("X-Forwarded-For") ||
context.Request.Headers.ContainsKey("X-Forwarded-Host") ||
context.Request.Headers.ContainsKey("Via");
}
private static bool haveCustomHostValue(HttpContext context)
{
// check if the host header is set to a custom value such as a domain name
if (IPAddress.TryParse(context.Request.Host.Host, out var ip))
{
// the host header is an IP address
// check if the IP address matches the server's IP address
return ip.Equals(context.Connection.LocalIpAddress);
}
// the host header is not an IP address
return true;
}
}
}