Where can I plug in a custom provider to set up the request context?
I want to run an ASP.NET MVC application in "slave" mode while gradually transitioning features from a legacy system. Each request will have a cookie, and I want to grab the cookie, make an external call to resolve it to a user identity, and set up that user identity for the remainder of the request.
I might set a forms authentication cookie, or use Session, but the source of truth about authentication has to be the externally-set cookie, on every request.
What's the best way to do this? Where do I plug in? I've looked at Authentication providers, and the Authorization attribute, but neither of those seems the right place for this.
I would have thought an HttpModule would be ideal for this scenario?
If I understand you correctly, I did something similar on a project I was working on recently:
public class UserSessionHttpModule : IHttpModule
{
private HttpApplication mApplication;
public void Dispose()
{
}
public void Init(HttpApplication context)
{
mApplication = context;
context.BeginRequest += new EventHandler(CheckUserSession);
}
private void CheckUserSession(Object sender, EventArgs e)
{
var extension = Path.GetExtension(mApplication.Context.Request.Path);
if (extension == "" || extension == ".aspx")
{
var userSessionService = ObjectFactory.GetInstance<IUserSessionService>();
userSessionService.CheckUserSession();
}
}
}
you could override the Init method in Global.asax page and listen to the PostAuthenticateRequest event, the events fires after authentication so you could change whatever values you like from the form authenticate cookies and inject your own
Related
My application requires 2 login mechanisms, one is Basic Authentication giving credentials in windows security dialog, the other way is kind of faking Basic Authentication meaning an encrypted username, password is sent as part of url in querystring say http://myurl.com?username=xxx&pwd=xxxxx
I have created a customModule like below
public class mymodule:IhttpModule
{
public void OnApplicationAuthenticateRequest(object sender, EventArgs e)
{
var context = ((HttpApplication)sender).Context;
if(context.Request.Querystring["username"]!=null)
{
//then write the cookie
createcookie();
}
else
{
//Request user for Basic authentication
context.Request.Headers["Authorization"])
}
}
}
1) When I call the URL like this http://myurl.com?username=xxx&pwd=xxxxx first request goes to AuthenticateRequest and cookie gets created, but the AuthenticateRequest gets called for multiple times and at one point Request.QueryString is null and it executes the line context.Request.Headers["Authorization"]) and it triggers Windows Security Dialog(basic authentication), how do I achieve my requirement.
I have a MVC4 web application set up, which uses Forms authentication and Web API for interaction. All API controllers use the [Authorize] attribute.
This was working just fine out of the box, until we started adding role support. Instead of implementing a full-fledged RoleProvider, I added a list of roles to the ticket's UserData, and created the following module:
public class SecurityModule : IHttpModule
{
public void Init(HttpApplication context)
{
var roleManager = (RoleManagerModule)context.Modules["RoleManager"];
roleManager.GetRoles += GetRoles;
}
void GetRoles(object sender, RoleManagerEventArgs e)
{
var user = e.Context.User;
if (user.Identity.IsAuthenticated && !(user is MyCustomPrincipal))
{
var roles = GetRolesFromFormsAuthCookie();
if (roles != null)
e.Context.User = new MyCustomPrincipal(user.Identity, roles,
otherData);
}
e.RolesPopulated = true;
}
}
This works flawlessly for MVC calls. For API, however, even though GetRoles gets called, when it reaches the corresponding method, it's back to GenericPrincipal.
How can I make this work with Web API too? Do I have to create a DelegatingHandler?
I'm also storing some custom data in my Principal, which might be a reason not to rely on just a RoleProvider (since I'd end up with a RolePrincipal), although I could just store that in the request context.
Update: I've now added a DelegatingHandler that does the same as the IHttpModule and sets Thread.CurrentPrincipal. Is this a reasonable approach?
Have you tried to set the Thread.CurrentPrincipal in the HttpModule as well ?. You can also use a Katana handler, which will work for both, ASP.NET MVC and ASP.NET Web API.
We have an ASP.NET MVC 4 intranet application. We’re using Windows Authentication and that aspect works fine. The user’s credentials are used and we can access those credentials from the web app.
What we really want is some sort of hybrid mode, however. We want to get the user’s credentials from the browser, but we also want to verify that the user is in our application’s database. If the user’s in the database, then they can just continue on. If they’re not, we want to redirect them to a page asking for alternate credentials. What I’m doing now is, in Global.asax.cs, I’ve got an Application_AuthenticateRequest method and I’m checking to see if the user is authenticated. If they are and their cookie information doesn’t reflect the fact that they’re logged into the system, then I log them in and set up some cookies with info about the user. If they’re not authenticated, I redirect them to a login page. We can’t use AD roles for reasons involved with company policy, so we need to use the database for additional authentication.
I’m guessing Application_AuthenticateRequest isn’t the place to do this, but maybe it is. But we basically need a place to filter the requests for authentication. But additionally this implementation leads me to another issue:
We have certain URLs in our app that allow anonymous access. I’ve added <location> tags to the web.config for these. The problem is, when anonymous calls are made into these, it gets to Application_AuthenticateRequest and tries to log the user into the DB. Now, I can add code into Application_AuthenticateRequest to handle these URLs and that’s currently my plan, but if I’m write and Application_AuthenticateRequest isn’t the place to be doing this, then I’d rather figure it out now than later.
You need to use Action Filters for this purpose. You can extend the AuthorizeAttribute like this:
public class MyAuthorizeAttribute : AuthorizeAttribute
{
private UnitOfWork _unitOfWork = new UnitOfWork();
protected override bool AuthorizeCore(HttpContextBase httpContext)
{
var isAuthorized = false;
var username = httpContext.User.Identity.Name;
// Some code to find the user in the database...
var user = _unitOfWork.UserRepository.Find(username);
if(user != null)
{
isAuthorized = true;
}
return isAuthorized;
}
public override void OnAuthorization(AuthorizationContext filterContext)
{
if (filterContext == null)
{
throw new ArgumentNullException("filterContext");
}
if (AuthorizeCore(filterContext.HttpContext))
{
SetCachePolicy(filterContext);
}
else
{
// If not authorized, redirect to the Login action
// of the Account controller...
filterContext.Result = new RedirectToRouteResult(
new System.Web.Routing.RouteValueDictionary {
{"controller", "Account"}, {"action", "Login"}
}
);
}
}
protected void SetCachePolicy(AuthorizationContext filterContext)
{
// ** IMPORTANT **
// Since we're performing authorization at the action level,
// the authorization code runs after the output caching module.
// In the worst case this could allow an authorized user
// to cause the page to be cached, then an unauthorized user would later
// be served the cached page. We work around this by telling proxies not to
// cache the sensitive page, then we hook our custom authorization code into
// the caching mechanism so that we have the final say on whether a page
// should be served from the cache.
HttpCachePolicyBase cachePolicy = filterContext.HttpContext.Response.Cache;
cachePolicy.SetProxyMaxAge(new TimeSpan(0));
cachePolicy.AddValidationCallback(CacheValidationHandler, null /* data */);
}
public void CacheValidationHandler(HttpContext context,
object data,
ref HttpValidationStatus validationStatus)
{
validationStatus = OnCacheAuthorization(new HttpContextWrapper(context));
}
}
Then, you can use this attribute at the Controller level or Action level like this:
[MyAuthorize]
public ActionResult SomeAction()
{
// Code that is supposed to be accessed by authorized users only
}
I am creating a custom ClaimsPrincipal that has additional claims using a custom AuthenticationManager. It appears that in ASP.NET 4.5 the AuthenticationManager is not automatically invoked and you have to manually invoke it. I have seen posts that suggest you do this in the PostAuthenticateRequest. My code looks like this in the Global.asax:
protected void Application_OnPostAuthenticateRequest(object sender, EventArgs e)
{
System.Web.HttpContext.Current.User =
FederatedAuthentication.FederationConfiguration.IdentityConfiguration.ClaimsAuthenticationManager.Authenticate("none",
System.Web.HttpContext.Current.User as ClaimsPrincipal);
}
I am using Forms Authentication with cookies. The current principal gets set correctly when the PostAuthenticateRequest is fired. The problem is that when the next request comes in to the ASP.NET Web API the custom claims are lost. I am using Web API for AJAX requests in a single page application (SPA). I suspect that what is in the current ClaimsPrincipal is being overwritten by what is in the cookie, but I am not sure. I am not using an inherited ClaimsPrincipal for type-safe retrieval of custom claims. I am just adding new claims which are subsequently lost somewhere in the process. What is the proper way to setup a custom ClaimsPrincipal so the additional claims are not loss between requests.
Here is the solution I came up with. First I used the FormsAuthentication_OnAuthenticate event instead of the Application_OnPostAuthenticateRequest event. I get the cookie to retrieve the authenticated users name and build a new claims principal with the claims I want to add. I do not add the roles as claims because the system adds them later in the authentication process and ends up duplicating them. This allows me to add custom claims to the principal for future processing in the application.
public void FormsAuthentication_OnAuthenticate(object sender, FormsAuthenticationEventArgs args)
{
if (FormsAuthentication.CookiesSupported)
{
if (Request.Cookies[FormsAuthentication.FormsCookieName] != null)
{
try
{
FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt(
Request.Cookies[FormsAuthentication.FormsCookieName].Value);
SaClaimsSecurity security = new SaClaimsSecurity();
//Do not add roles here because the security framework adds them
//somewhere else in the chain and will duplicate roles
ClaimsPrincipal principal = security.CreateClaimsPrincipalWithoutRoles(ticket.Name);
args.User = principal;
}
catch (Exception e)
{
// Decrypt method failed.
}
}
}
else
{
throw new HttpException("Cookieless Forms Authentication is not " +
"supported for this application.");
}
}
Scenario
I develop an MVC application that will be hosted in Windows Azure. During development, I test against a local database and local user membership service. In production, the application hits off a SQL Azure database and a cloud-hosted user membership service.
Sometimes I'll log in to the local version of the site with a user account that only exists on my local machine. If I forget to log out but switch my machine out of test mode, things start to break.
The Problem
I set my hosts file to point my application URL at 127.255.0.0 so that browser requests are handled by the Azure emulator locally. This also means my test application and the production application use the same host name - cookies for one are seen as valid cookies for the other.
If I log in to my local system, an ASPXAUTH cookie is created for the domain and contains the credentials of the user from my local system. If I forget to log out and switch my hosts file back to normal (browser requests go to the live application), it sends the same ASPXAUTH cookie to the server.
Since this user doesn't exist on the server, only locally, any requests like Membership.GetUser().Email return an object null exception.
What I'd Like to Do
Ideally, I could inject some code early in the request to check that the user exists. Something like:
MembershipUser user = Membership.GetUser();
if(user == null) {
FormsAuthentication.SignOut();
}
This will automatically remove the ASPXAUTH cookie for invalid users. But where do I put it? I started looking at my controllers - all of them inherit from a BaseController class, but even putting this code in the base controller's constructor isn't early enough. I also looked at Global.asax, but I'm not sure which event would be best to tie this action to.
Also, I'm not even sure this is the right way to do things. If not, what is the best way to ensure that the authentication cookie is for a valid user before just depending on the membership class like I am currently?
You may handle the below event in you global.aspx:
public void FormsAuthentication_OnAuthenticate(object sender, FormsAuthenticationEventArgs args)
{
}
EDIT:
In the above method, Membership.GetUser() will return null, since it takes the userName from HttpContext.Current.User.Identity.Name property and in this event the user has not yet been authenticated. The above method is invoked by FormsAuthenticationModule when it raised Authenticate even. You can handle this event like so:
public void FormsAuthentication_OnAuthenticate(object sender, FormsAuthenticationEventArgs args)
{
if (FormsAuthentication.CookiesSupported &&
Request.Cookies[FormsAuthentication.FormsCookieName] != null)
{
try
{
var formsAuthTicket = FormsAuthentication.Decrypt(Request.Cookies[FormsAuthentication.FormsCookieName].Value);
MembershipUser user = Membership.GetUser(formsAuthTicket.Name);
if (user == null)
{
FormsAuthentication.SignOut();
Request.Cookies[FormsAuthentication.FormsCookieName].Value = null;
}
}
catch (Exception ex)
{
//TODO:log ex
}
}
}
You can also consider to handle the AuthenticateRequest event by declaring the below method in the global.aspx.
NOTE: Application_AuthenticateRequest event is fired after the FormsAuthentication_OnAuthenticate event.
void Application_AuthenticateRequest(object sender, EventArgs e)
{
if (HttpContext.Current.User != null && HttpContext.Current.User.Identity.IsAuthenticated)
{
MembershipUser user = Membership.GetUser();
if (user == null)
{
FormsAuthentication.SignOut();
HttpContext.Current.User = null;
}
}
}
Hope this helps..
You create a base controller that overrides the OnActionExecuting and place your code there.
Have all your controller controllers inherit from him. This the OnActionExecuting from a older project I had
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
if (Request.IsAuthenticated)
{
if (Session[SomeKey] == null)
{
filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary { { "controller", "Account" }, { "action", "LogOff" } });
}
}
base.OnActionExecuting(filterContext);
}
I'm basically checking if the request is authenticated otherwise I redirect it to logout action.
http://msdn.microsoft.com/en-us/library/system.web.mvc.controller.onactionexecuting.aspx