首先,我们来看下stack overflow网站的请求头文件:
可以看到一些我们熟悉或是陌生的HTTP头部文件字段。
在这里我们在对HTTP输入流的头部文件中,做一些基本的防护。首先要明确,既然我们是对HTTP头部做处理,那么就需要在Startup.cs类的
Configuration方法中做处理,因为这里就是处理HTTP输入流的。
首先做一些基本的处理,比如中间件和基本的类:
public class SecurityHeadersPolicy
{
public IDictionary SetHeaders { get; }
= new Dictionary();
public ISet RemoveHeaders { get; }
= new HashSet();
}
这里的头部信息是我们定义好的,用来增加或是删除头部信息,然后就是我们的中间件:
public class SecurityHeadersMiddleware { private readonly RequestDelegate _next; private readonly SecurityHeadersPolicy _policy; public SecurityHeadersMiddleware(RequestDelegate next, SecurityHeadersPolicy policy) { _next = next; _policy = policy; } public async Task Invoke(HttpContext context) { IHeaderDictionary headers = context.Response.Headers; foreach (var headerValuePair in _policy.SetHeaders) { headers[headerValuePair.Key] = headerValuePair.Value; } foreach (var header in _policy.RemoveHeaders) { headers.Remove(header); } await _next(context); } }
基于IApplicationBuilder接口做一个中间件的扩展方法:
public static class MiddlewareExtensions { public static IApplicationBuilder UseSecurityHeadersMiddleware(this IApplicationBuilder app, SecurityHeadersBuilder builder) { SecurityHeaderPolicy policy = builder.Build(); return app.UseMiddleware(policy); } }
封装好相关的安全类:
public class SecurityHeadersBuilder { private readonly SecurityHeadersPolicy _policy = new SecurityHeadersPolicy(); public SecurityHeadersBuilder AddDefaultSecurePolicy() { AddFrameOptionsDeny(); AddXssProtectionBlock(); AddContentTypeOptionsNoSniff(); AddStrictTransportSecurityMaxAge(); RemoveServerHeader(); return this; } public SecurityHeadersBuilder AddFrameOptionsDeny() { _policy.SetHeaders[FrameOptionsConstants.Header] = FrameOptionsConstants.Deny; return this; } public SecurityHeadersBuilder AddFrameOptionsSameOrigin() { _policy.SetHeaders[FrameOptionsConstants.Header] = FrameOptionsConstants.SameOrigin; return this; } public SecurityHeadersBuilder AddFrameOptionsSameOrigin(string uri) { _policy.SetHeaders[FrameOptionsConstants.Header] = string.Format(FrameOptionsConstants.AllowFromUri, uri); return this; } public SecurityHeadersBuilder RemoveServerHeader() { _policy.RemoveHeaders.Add(ServerConstants.Header); return this; } public SecurityHeadersBuilder AddCustomHeader(string header, string value) { _policy.SetHeaders[header] = value; return this; } public SecurityHeadersBuilder RemoveHeader(string header) { _policy.RemoveHeaders.Add(header); return this; } public SecurityHeadersPolicy Build() { return _policy; } }
最后注入到HTTP的输入流中:
app.UseSecurityHeadersMiddleware(new SecurityHeadersBuilder() .AddDefaultSecurePolicy() );
然后我们浏览一下网页,就可以在HTTP的头部信息中看到:
HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 X-Frame-Options: DENY X-XSS-Protection: 1; mode=block X-Content-Type-Options: nosniff Strict-Transport-Security: max-age=31536000 X-Powered-By: ASP.NET
还有一个就是CSRF的防护,如果之前你用过ASP.NET MVC,在最基本的MVC模板中,可能你会留意到已有的cshtml页面中的form表单有这么一句:
@Html.AntiForgeryToken()
这就是微软在MVC框架中为我们提供的防护CSRF的方法。我们在表单中直接使用上面那句代码就可以了,然后在表单提交的Action方法中:
[ValidateAntiForgeryToken] [HttpPost] public IActionResult AntiForm(string message) { return Content(message); }
使用[ValidateAntiForgeryToken]属性,来验证CSRF。
参考链接:
How to add security headers in ASP.NET Core using custom middleware(如何使用自定义中间件在ASP.NET Core中添加安全标头)
初探CSRF在ASP.NET Core中的处理方式
代码地址:
https://github.com/RyanOvO/aspnetcore-fileup-demo