I am working on an asp.net mvc 4 web application , and i wrote the following custom authorization class:-
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public class CheckUserPermissionsAttribute : AuthorizeAttribute
{
public string Model { get; set; }
public string Action { get; set; }
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
if (!httpContext.Request.IsAuthenticated)
return false;
//code goes here
if (!repository.can(ADusername, Model, value)) // implement this method based on your tables and logic
{
return false;
//base.HandleUnauthorizedRequest(filterContext);
}
return true;
// base.OnAuthorization(filterContext);
}
protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
{
if (filterContext.HttpContext.Request.IsAjaxRequest())
{
var viewResult = new JsonResult();
viewResult.JsonRequestBehavior = JsonRequestBehavior.AllowGet;
viewResult.Data = (new { IsSuccess = "Unauthorized", description = "Sorry, you do not have the required permission to perform this action." });
filterContext.Result = viewResult;
}
else
{
var viewResult = new ViewResult();
viewResult.ViewName = "~/Views/Errors/_Unauthorized.cshtml";
filterContext.Result = viewResult;
}
base.HandleUnauthorizedRequest(filterContext);
}
}
}
but the only problem i am facing now is that if the authorization fail then the user will be prompted to enter username and password, although i have override the HandleUnauthorizedRequest to return a view or JSON based on if the request is AJAX or not. so can you advice why the user is being prompted to enter his username and password when the authorization fail, instead of receiving the _unauthorized view or the JSON containing an error message
but the only problem i am facing now is that if the authorization fail
then the user will be prompted to enter username and password,
although i have override the HandleUnauthorizedRequest to return a
view or JSON based on if the request is AJAX or not.
That's because you are absolutely always hitting the following line in your HandleUnauthorizedRequest method:
base.HandleUnauthorizedRequest(filterContext);
You know what this line do? It calls the base method. You know what the base method do? It returns 401 status code. You know what happens when 401 status response code is returned in an ASP.NET application in which you are using Forms Authentication? You get the login page.
So yeah, if you are using AJAX or something and intend to be returning some JSON or something make sure that the base stuff is never called. By the way in your else condition you seem to be attempting to render some ~/Views/Errors/_Unauthorized.cshtml view which obviously is useless once again because you are also calling the base method which will simply redirect to the login page.
I think that at this stage of my answer you already know what to do: get rid of this last line of your HandleUnauthorizedRequest method in which you are throwing all your efforts into the trash by calling the base method.
And if you want to do things properly and return 401 status code and not get the login page but instead return some custom JSON you could use the SuppressFormsAuthenticationRedirect property on the Response object. And if you are using some legacy version of the .NET framework which doesn't have this property you might find the following blog post useful in which Phil Haack explains how to handle this case.
Related
I'm trying to implement POST-REDIRECT-GET technique where I post a JSON string to my razor OnPost method. This in turn redirects to OnGet method that takes in that string parameter. How do I hide this input parameter string to my OnGet method?
Edit: I tried using ViewData but the value is always null in my OnGet method even though I set it before redirect.
public async Task<IActionResult> OnPostData(string input_JSON)
{
TempData["InputJSON"] = input_JSON;
return RedirectToPage("GetData");
}
public async Task<IActionResult> OnGetGetData()
{
string tempData = TempData["InputJSON"] as string;
//do somethig with string;
}
I do form post in my javascript and when the new window opens, I see the input_string in my URL. How do I pass parameters between methods?
https://learn.microsoft.com/en-us/aspnet/core/security/gdpr?view=aspnetcore-2.2#tempdata-provider-and-session-state-cookies-arent-essential
According to Microsoft, TempData provider and session state cookies aren't essential. I had to make it essential in my Startup.cs file's ConfigureServices:
services.Configure<CookieTempDataProviderOptions>(options => {
options.Cookie.IsEssential = true;
});
I have the following Api Controller:
[HttpPost]
public User Create(User user)
{
User user = _domain.CreateUser(user);
//set location header to /api/users/{id}
//set status code to 201
//return the created user
}
It seems like we have to depend on Request.CreateResponse(..) and change the signature of the controller so as to return IHttpActionResult.
I do not want to change the method signature as it is very useful for the documentation purpose. I am able to add the Location header using HttpContext.Current.Response... but not able to set the status code.
Anybody has any better idea on this?
Because you are using a custom (other) return type outside of void, HttpResponseMessage, and IHttpActionResult - it's harder to specify the status code. See Action Results in Web API 2.
From Exception Handling in Web API. If you want to stick with not modifying the return type then this might be something you can do to set the status code:
[HttpPost]
public User Create(User user)
{
User user = _domain.CreateUser(user);
//set location header to /api/users/{id}
//set status code to 201
if (user != null)
{
//return the created user
throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.Created, user);
}
else
{
throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.InternalServerError));
}
}
I'm trying to create a simple user authentication function but I just can't get it to work.
Here is the code I'm working on:
public class LoginController : ApiController
{
private void SetPrincipal(IPrincipal principal)
{
Thread.CurrentPrincipal = principal;
if (HttpContext.Current != null)
{
HttpContext.Current.User = principal;
}
}
public bool Login(string token)
{
//Check token
if (.....)
{
//Authenticate user
var identity = new GenericIdentity("Test user");
SetPrincipal(new GenericPrincipal(identity, new string[]{"Test role"}));
}
}
[Authorize]
public string TestFun()
{
return "Hello " + User.Identity.Name;
}
}
So, if I try to call method TestFun() first, it returns error code 401 like it should.
However when I call method Login() it should somehow save user credentials, but this is where I get lost, I just can't get it to work.
TestFun() always returns error code 401 even if I call Login() first.
If I try to put return "Hello " + User.Identity.Name; in the Login() function it returns correct username, but in the TestFun() the user is not available.
I've even tried using Sessions and FormsAuthentication but I just can't get it to work, even on this really simple example.
Can someone please tell me what am I missing?
Thanks!
The Login method sets the principal for current request only. Just after the request completes, the principal context is wiped out so that the server can handle other requests for other users. When a new request comes, eons later from the server perspective, the principal context no longer exists and if nothing restores it, the request is unauthenticated.
To fix this you have to return something from your login method to the client. Not only bool but rather - an authentication token. Something the client could use to authenticate further requests.
It could be anything. Forms cookie would be fine as long as the client remembers to append it to further requests. Another common practice is to have a custom authentication token returned to the client and then appended by the client in a custom authentication header. And as forms cookies are handled by the Forms Authentication module, custom headers would need a custom mvc authentication filter or custom asp.net authentication module so that the token is readed, the identity is extracted and restored just before the request is about to execute.
If you don't like to bake your own token infrastructure, I would also recommend OAuth2 tokens. There is a great book that contains easy to follow examples on this and other possible authentication methods:
http://www.amazon.com/Pro-ASP-NET-Web-API-Security/dp/1430257822/ref=sr_1_1?ie=UTF8&sr=8-1&keywords=web+api+security
I just got the same issue, yes, I agreed we need to save that principal into somewhere (cookie, session) for other action to use, so, in SetPrincipal function I added
HttpContext.Current.Session["user"] = HttpContext.Current.User;
Now, the issue is how to get it back for other action, the idea popups in my mind is to extend AuthorizeAttribute and override IsAuthrized function, it will read the session first and if it found the session, it will return true, otherwise it will return false.
namespace BinZ
{
public class MyAuthorizeAttribute:AuthorizeAttribute
{
protected override bool IsAuthorized(HttpActionContext actionContext) {
HttpContext.Current.User = HttpContext.Current.Session["user"] as IPrincipal;
return HttpContext.Current.User != null;
}
}
}
Please remember to replace [Authorize] to [MyAuthorizeAttribute] in WebApi controller.
It works for me very well.
Cheers
I want to understand the difference in the behavior of a program when we call FormsAuthentication.RedirectFromLoginPage vs. when we call Response.Redirect(FormsAuthentication.GetRedirectUrl()) and manually redirect.
Please see the comments below.
I have a LoginController/Index (two actions, one for HttpGet and one for HttpPost). The View of this controller represents the application's login page.
I also have a home page or landing page, i.e. the page that the user must be taken to after a successful login. This is represented in my application by the HomeController's Index action and the ~Views/Home/Index.cshtml view.
I have presented three scenarios. I understand scenario 1 and I expect it to work the way it does, but I noted a difference in scenarios 2 and 3.
Scenario 1
namespace Controllers
{
[AllowAnonymous]
public class LoginController : Controller
{
[HttpPost]
public ActionResult Index(Login loginViewModel)
{
if (ModelState.IsValid)
{
var user = ValidateUser(loginViewModel);
if (user != null)
{
// Other stuff: set cookies, session state, etc.
return RedirectToAction("Index", "Home");
}
else
{
ModelState.AddModelError("", "Invalid password. Please try again.");
}
}
// If the user was a valid user, the flow-of-control won't reach here
// as expected and the user will be taken to the view that is served
// by the HomeController::Index() action. If it is by convention, it will
// be the ~Views/Home/Index.cshtml view. This is fine.
return View();
}
}
}
Scenario 2
namespace Controllers
{
[AllowAnonymous]
public class LoginController : Controller
{
[HttpPost]
public ActionResult Index(Login loginViewModel)
{
if (ModelState.IsValid)
{
var user = ValidateUser(loginViewModel);
if (user != null)
{
// Other stuff: set cookies, session state, etc.
Response.Redirect(FormsAuthentication.GetRedirectUrl(loginViewModel.UserName,
loginViewModel.RememberMe));
}
else
{
ModelState.AddModelError("", "Invalid password. Please try again.");
}
}
// If the user was a valid user, the flow-of-control still reaches here
// as expected. And as expected, it renders the same View, i.e. the View
// associated with the controller we are in, which is ~Views/Login/Index,
// which represents the login page. This is wrong. I shouldn't redirect here.
// I understand this. My question here is two fold:
// 1) I am simply trying to understand the difference in behaviors of the three
// scenarios described in this question.
// 2) Given this, the right way would be to not use Response.Redirect here but instead
// use RedirectToAction. However, if I wanted to use Response.Redirect, what should
// I do?
return View();
}
}
}
Scenario 3
namespace Controllers
{
[AllowAnonymous]
public class LoginController : Controller
{
[HttpPost]
public ActionResult Index(Login loginViewModel)
{
if (ModelState.IsValid)
{
var user = ValidateUser(loginViewModel);
if (user != null)
{
// Other stuff: set cookies, session state, etc.
FormsAuthentication.RedirectFromLoginPage(loginViewModel.UserName,
loginViewModel.RememberMe);
}
else
{
ModelState.AddModelError("", "Invalid password. Please try again.");
}
}
// If the user was a valid user, the flow-of-control still reaches here
// as expected. However, magically, somehow, even though the statement below
// suggests that the user must be taken to the View of the same controller and
// action that we are currently in, i.e. the View of the LoginController::Index()
// action, i.e. the ~Views/Login/Index.cshtml, it magically takes me to the
// ~Views/Home/Index.cshtml instead, which is what is specified as the LoginPage
// attribute of the <authentication>/<forms> element in the web.config.
// I want to know how this happens.
return View();
}
}
}
Update
I am at my wit's end now. Now, even Scenario 1 that uses RedirectToAction is calling the Index() action on the LoginController class.
The actual difference is that FormsAuthentication.RedirectFromLoginPage() sets cookies and then makes redirects but FormsAuthentication.GetRedirectUrl() only returns redirect url.
The funny thing is that implementation of FormsAuthentication.GetRedirectUrl() is like this:
public static String GetRedirectUrl(String userName, bool createPersistentCookie)
{
if (userName == null)
return null;
return GetReturnUrl(true);
}
So actually userName and createPersistentCookie parameters are completely ignored. You must call FormsAuthentication.SetAuthCookie( userName, true/false ) manually before calling GetRedirectUrl.
Agree with Vasily.
RedirectFromLoginPage issues an authentication ticket and places it in the default cookie using the SetAuthCookie method.
You can read something about this behavior here.
If you want to have a better control over the cookie creation you should (encryption, expiration, extending the principal) you should create the cookie yourself.
I explained the whole process here and here.
How do you handle ajax requests when user is not authenticated?
Someone enters the page, leaves room for an hour, returns, adds comment on the page that goes throuh ajax using jQuery ($.post). Since he is not authenticated, method return RedirectToRoute result (redirects to login page). What do you do with it? How do you handle it on client side and how do you handle it in controller?
EDIT:
I wrote above answer a long time ago and now I believe that sending 403 is not proper way to go. 403 has slightly different meaning and it just shouldn't be used. This is corrected attribute using 401. It differs only with additional context.HttpContext.Response.End() in Http401Result and different HTTP code:
public class OptionalAuthorizeAttribute : AuthorizeAttribute
{
private class Http401Result : ActionResult
{
public override void ExecuteResult(ControllerContext context)
{
// Set the response code to 401.
context.HttpContext.Response.StatusCode = 401;
context.HttpContext.Response.Write(CTRes.AuthorizationLostPleaseLogOutAndLogInAgainToContinue);
context.HttpContext.Response.End();
}
}
private readonly bool _authorize;
public OptionalAuthorizeAttribute()
{
_authorize = true;
}
//OptionalAuthorize is turned on on base controller class, so it has to be turned off on some controller.
//That is why parameter is introduced.
public OptionalAuthorizeAttribute(bool authorize)
{
_authorize = authorize;
}
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
//When authorize parameter is set to false, not authorization should be performed.
if (!_authorize)
return true;
var result = base.AuthorizeCore(httpContext);
return result;
}
protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
{
if (filterContext.RequestContext.HttpContext.Request.IsAjaxRequest())
{
//Ajax request doesn't return to login page, it just returns 401 error.
filterContext.Result = new Http401Result();
}
else
base.HandleUnauthorizedRequest(filterContext);
}
}
OLD ANSWER:
While I like the ideas posted in other answers (which I had an idea about earlier), I needed code samples. Here they are:
Modified Authorize attribute:
public class OptionalAuthorizeAttribute : AuthorizeAttribute
{
private class Http403Result : ActionResult
{
public override void ExecuteResult(ControllerContext context)
{
// Set the response code to 403.
context.HttpContext.Response.StatusCode = 403;
context.HttpContext.Response.Write(CTRes.AuthorizationLostPleaseLogOutAndLogInAgainToContinue);
}
}
private readonly bool _authorize;
public OptionalAuthorizeAttribute()
{
_authorize = true;
}
//OptionalAuthorize is turned on on base controller class, so it has to be turned off on some controller.
//That is why parameter is introduced.
public OptionalAuthorizeAttribute(bool authorize)
{
_authorize = authorize;
}
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
//When authorize parameter is set to false, not authorization should be performed.
if (!_authorize)
return true;
var result = base.AuthorizeCore(httpContext);
return result;
}
protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
{
if (filterContext.RequestContext.HttpContext.Request.IsAjaxRequest())
{
//Ajax request doesn't return to login page, it just returns 403 error.
filterContext.Result = new Http403Result();
}
else
base.HandleUnauthorizedRequest(filterContext);
}
}
HandleUnauthorizedRequest is overridden, so it returns Http403Result when using Ajax. Http403Result changes StatusCode to 403 and returns message to the user in response. There is some additional logic in attribute (authorize parameter), because I turn on [Authorize] in the base controller and disable it in some pages.
The other important part is global handling of this response on client side. This is what I placed in Site.Master:
<script type="text/javascript">
$(document).ready(
function() {
$("body").ajaxError(
function(e,request) {
if (request.status == 403) {
alert(request.responseText);
window.location = '/Logout';
}
}
);
}
);
</script>
I place a GLOBAL ajax error handler and when ever $.post fails with a 403 error, the response message is alerted and the user is redirected to logout page. Now I don't have to handle the error in every $.post request, because it is handled globally.
Why 403, and not 401? 401 is handled internally by MVC framework (that is why redirection to login page is done after failed authorization).
What do you think about it?
The idea I came up with when a coworker asked about how to handle it was this - make an AuthorizeAjax attribute. It can interrogate and verify that Request.IsAjaxRequest() and, if the request isn't authenticated, return a specific JSON error object. It's possible you could simply override the default AuthorizeAttribute and have it call the base unless it's an unauthorized AJAX request so you don't have to worry about whether to tag controller actions with [Authorize] or [AuthorizeAjax].
On the client-side, all your pages would have to be equipped to deal with the returned error, but that logic can likely be shared.
I would propose creating your own AuthorizeAttribute and if the request is an Ajax request, throw an HttpException(401/403). And also switch to use jQuery's Ajax Method instead.
Assuming you've implemented error pages and they return the correct status code, the error callback will be executed instead of the success callback. This will be happen because of the response code.
The simplest and cleanest solution I've found for this is to register a callback with the jQuery.ajaxSuccess() event and check for the "X-AspNetMvc-Version" response header.
Every jQuery Ajax request in my app is handled by Mvc so if the header is missing I know my request has been redirected to the login page, and I simply reload the page for a top-level redirect:
$(document).ajaxSuccess(function(event, XMLHttpRequest, ajaxOptions) {
// if request returns non MVC page reload because this means the user
// session has expired
var mvcHeaderName = "X-AspNetMvc-Version";
var mvcHeaderValue = XMLHttpRequest.getResponseHeader(mvcHeaderName);
if (!mvcHeaderValue) {
location.reload();
}
});
The page reload may cause some Javascript errors (depending on what you're doing with the Ajax response) but in most cases where debugging is off the user will never see these.
If you don't want to use the built-in header I'm sure you could easily add a custom one and follow the same pattern.
Here's a solution I use. It is dead simple, if a bit brute-force. I like it because I'm lazy and I don't want to think about special attributes on action methods and I don't want to write ajax error handlers if I don't have to (although there's no reason client script couldn't detect the 403 status code and do something user friendly).
Putting this in Global.axax detects any unauthenticated ajax request and simply returns 403, with no content. This prevents unauthenticated ajax calls getting redirected to the login form when forms authentication is in use.
protected void Application_AuthenticateRequest(object sender, EventArgs e)
{
// Prevent Ajax requests from being returned the login form when not authenticated
// (eg. after authentication timeout).
if ((Request.Headers["X-Requested-With"] != null && Request.Headers["X-Requested-With"] == "XMLHttpRequest")
||
(Request["X-Requested-With"] != null && Request["X-Requested-With"] == "XMLHttpRequest"))
{
if (!Request.IsAuthenticated)
{
Response.Clear();
Response.StatusCode = 403;
Response.Flush();
Response.End();
}
}
}
You can detect ajax request and send 401, and on client side you can even show an ajax dialog with login prompt, after which you can "continue" your failed ajax request and make your application work and user feel like session timeout never happened. See this answer for details.