Question

我们有一些现有的MVC Web服务，从Web页面称为AJAX样式。这些服务使用ValidateAntiForgeryToken属性来帮助防止请求伪造。

我们希望将这些服务迁移到Web API，但似乎没有等效的防伪功能。

我错过了什么吗？是否有不同的方法来解决Web API请求伪造问题？

Answer 1

您可以实现此类授权属性：

[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
public sealed class ValidateAntiForgeryTokenAttribute : FilterAttribute, IAuthorizationFilter
{
    public Task<HttpResponseMessage> ExecuteAuthorizationFilterAsync(HttpActionContext actionContext, CancellationToken cancellationToken, Func<Task<HttpResponseMessage>> continuation)
    {
        try
        {
            AntiForgery.Validate();
        }
        catch
        {
            actionContext.Response = new HttpResponseMessage 
            { 
                StatusCode = HttpStatusCode.Forbidden, 
                RequestMessage = actionContext.ControllerContext.Request 
            };
            return FromResult(actionContext.Response);
        }
        return continuation();
    }

    private Task<HttpResponseMessage> FromResult(HttpResponseMessage result)
    {
        var source = new TaskCompletionSource<HttpResponseMessage>();
        source.SetResult(result);
        return source.Task;
    }
}

然后用它装饰你的API动作：

[ValidateAntiForgeryToken]
public HttpResponseMessage Post()
{
    // some work
    return Request.CreateResponse(HttpStatusCode.Accepted);
}

Answer 2

补充以上代码 FilterAttribute

[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
    public sealed class ValidateAntiForgeryTokenAttribute : FilterAttribute, IAuthorizationFilter
    {
        public Task<HttpResponseMessage> ExecuteAuthorizationFilterAsync(HttpActionContext actionContext, CancellationToken cancellationToken, Func<Task<HttpResponseMessage>> continuation)
        {
            try
            {
                string cookieToken = "";
                string formToken = "";

                IEnumerable<string> tokenHeaders;
                if (actionContext.Request.Headers.TryGetValues("RequestVerificationToken", out tokenHeaders))
                {
                    string[] tokens = tokenHeaders.First().Split(':');
                    if (tokens.Length == 2)
                    {
                        cookieToken = tokens[0].Trim();
                        formToken = tokens[1].Trim();
                    }
                }
                AntiForgery.Validate(cookieToken, formToken);
            }
            catch (System.Web.Mvc.HttpAntiForgeryException e)
            {
                actionContext.Response = new HttpResponseMessage
                {
                    StatusCode = HttpStatusCode.Forbidden,
                    RequestMessage = actionContext.ControllerContext.Request
                };
                return FromResult(actionContext.Response);
            }
            return continuation();
        }

        private Task<HttpResponseMessage> FromResult(HttpResponseMessage result)
        {
            var source = new TaskCompletionSource<HttpResponseMessage>();
            source.SetResult(result);
            return source.Task;
        }

使用Razor的Html函数

@functions{
    public string TokenHeaderValue()
        {
            string cookieToken, formToken;
            AntiForgery.GetTokens(null, out cookieToken, out formToken);
            return cookieToken + ":" + formToken;
        }
}

使用Angular

return $http({
   method: 'POST',
   url: '@Url.Content("~/api/invite/")',
   data: {},
   headers: {
       'RequestVerificationToken': '@TokenHeaderValue()'
   }
});

Answer 3

这个link有帮助，您可以从剃刀视图中检索防伪令牌，并将令牌作为标题传递：

var csrfToken = $("input[name='__RequestVerificationToken']").val(); 
$.ajax({
    headers: { __RequestVerificationToken: csrfToken },
    type: "POST",
    dataType: "json",
    contentType: 'application/json; charset=utf-8',
    url: "/api/products",
    data: JSON.stringify({ name: "Milk", price: 2.33 }),
    statusCode: {
        200: function () {
            alert("Success!");
        }
    }
});

Answer 4

Oswaldo的回答，但是作为AuthorizeAttribute实现

  [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
  public class ApiValidateAntiForgeryToken : AuthorizeAttribute
  {
    public static string GenerateAntiForgeryTokenForHeader() {
      string cookieToken, formToken;
      AntiForgery.GetTokens(null, out cookieToken, out formToken);
      return cookieToken + ":" + formToken;
    }


    protected override bool IsAuthorized(HttpActionContext actionContext) {
      var headers = actionContext.Request.Headers;

      // we pass both the cookie and the form token into a single header field
      string headerToken = headers.Contains("__RequestVerificationToken") ? headers.GetValues("__RequestVerificationToken").FirstOrDefault() : null;

      if (headerToken == null) {
        return false;
      }

      string[] tokens = headerToken.Split(':');
      if (tokens.Length != 2) {
        return false;
      }

      string cookieToken = tokens[0].Trim();
      string formToken = tokens[1].Trim();

      try {
        AntiForgery.Validate(cookieToken, formToken);
      }
      catch {
        return false;
      }

      return base.IsAuthorized(actionContext);
    }
  }

您可以使用[ApiValidateAntiForgeryToken]装饰您的控制器或方法，然后传递RequestVerificationToken：“@ ApiValidateAntiForgeryToken.GenerateAntiForgeryTokenForHeader（）”作为剃刀javascript代码中方法的标题。

Answer 5

在考虑了这个之后，混合cookie和表单标记是一个坏主意，因为它会破坏防伪标记的整个目的。最好将cookie部分保存为cookie，同时将表单部分移动到auth标头，因此这个新答案（同样作为AuthorizeAttribute）。

using System;
using System.Linq;
using System.Net.Http;
using System.Web;
using System.Web.Helpers;
using System.Web.Http;
using System.Web.Http.Controllers;

  [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
  public class ApiValidateAntiForgeryToken : AuthorizeAttribute {
    public const string HeaderName = "X-RequestVerificationToken";

    private static string CookieName => AntiForgeryConfig.CookieName;

    public static string GenerateAntiForgeryTokenForHeader(HttpContext httpContext) {
      if (httpContext == null) {
        throw new ArgumentNullException(nameof(httpContext));
      }

      // check that if the cookie is set to require ssl then we must be using it
      if (AntiForgeryConfig.RequireSsl && !httpContext.Request.IsSecureConnection) {
        throw new InvalidOperationException("Cannot generate an Anti Forgery Token for a non secure context");
      }

      // try to find the old cookie token
      string oldCookieToken = null;
      try {
        var token = httpContext.Request.Cookies[CookieName];
        if (!string.IsNullOrEmpty(token?.Value)) {
          oldCookieToken = token.Value;
        }
      }
      catch {
        // do nothing
      }

      string cookieToken, formToken;
      AntiForgery.GetTokens(oldCookieToken, out cookieToken, out formToken);

      // set the cookie on the response if we got a new one
      if (cookieToken != null) {
        var cookie = new HttpCookie(CookieName, cookieToken) {
          HttpOnly = true,
        };
        // note: don't set it directly since the default value is automatically populated from the <httpCookies> config element
        if (AntiForgeryConfig.RequireSsl) {
          cookie.Secure = AntiForgeryConfig.RequireSsl;
        }
        httpContext.Response.Cookies.Set(cookie);
      }

      return formToken;
    }


    protected override bool IsAuthorized(HttpActionContext actionContext) {
      if (HttpContext.Current == null) {
        // we need a context to be able to use AntiForgery
        return false;
      }

      var headers = actionContext.Request.Headers;
      var cookies = headers.GetCookies();

      // check that if the cookie is set to require ssl then we must honor it
      if (AntiForgeryConfig.RequireSsl && !HttpContext.Current.Request.IsSecureConnection) {
        return false;
      }

      try {
        string cookieToken = cookies.Select(c => c[CookieName]).FirstOrDefault()?.Value?.Trim(); // this throws if the cookie does not exist
        string formToken = headers.GetValues(HeaderName).FirstOrDefault()?.Trim();

        if (string.IsNullOrEmpty(cookieToken) || string.IsNullOrEmpty(formToken)) {
          return false;
        }

        AntiForgery.Validate(cookieToken, formToken);
        return base.IsAuthorized(actionContext);
      }
      catch {
        return false;
      }
    }
  }

然后用[ApiValidateAntiForgeryToken]装饰您的控制器或方法

并添加到剃刀文件中以生成javascript的令牌：

<script>
var antiForgeryToken = '@ApiValidateAntiForgeryToken.GenerateAntiForgeryTokenForHeader(HttpContext.Current)';
// your code here that uses such token, basically setting it as a 'X-RequestVerificationToken' header for any AJAX calls
</script>

Web API和ValidateAntiForgeryToken

5 个答案: