Need help understanding ASP .Net MVC user authentication/authorization - asp.net

I have been going around in circles trying to properly understand this.
I have an ASP .Net MVC project I am working on and need to implement user logins that authorize and authenticate against en external system (via webservice).
I can't seem to get my head around MembershipProvider and AuthorizeAttribute in the context that I require.
Which do I need to use (I believe its both) and where do I need to customize to provide the authentication against an external system.
There is one additional thing I also require on top of the default ASP .Net user principals in that the external webservice will return a session ID upon successful login that would be used for subsequent requests to external services.
Would someone be able to point me in the direction of some useful example of this sort of set up?

MembershipProvider is used to provide the users that may login the system. The RoleProvider is used to tell which roles a user has. They are used during the authentication process. i.e. identifying the user. You can read about membership vs roles
The [Authorize] attribute on the other hand is used during authorization. i.e. to check if the user is allowed to do something.

Related

ASP.NET Identity - Windows Authentication and Web Services

ASP.NET Identity - Windows Authentication and Web Services
All of the web applications I create for my job I do for the Intranet so we use Windows Authentication. However, in order to get any other information for the current user (email, phone, office) I need to consume a web service that is provided by another department. To get the information I pass the User's Name property to the web service and use a class I've written to store the information. I then store this object in a session and use it whenever needed.
While this works fine I know there must be a better way. I've recently looked into the identity framework and while it looks great I'm not exactly sure if it's the right fit for my situation. Most of the examples I look at have it work with a database to register and log in users. My users will never need to log in nor will they need to be created, at least not within the application. I basically just need to be able to store the data from the web service in the identity. Is this possible?
After enough looking around I was able to solve my problem. Using these links I figured out where I needed to load my user data, set my claims, and then how to use the claims to authorize my controllers.
http://www.mytechnotes.me/2015/08/04/56/
http://leastprivilege.com/2012/10/26/using-claims-based-authorization-in-mvc-and-web-api/

ADFS in ASP.NET usage

I am relatively new to uisng ADFS (in ASP.NET) which is what my company wants to use and just have a few basic questions about that:
Am I correct there is no explicit "Authorize" call you can do like with ASP.NET Membership Providers? Unless you on a domain it presents you with a login screen and once you enter credentials it does validation and returns back a token with claims information.
Can you configure some forms to allow anonymous access like you can do with Forms Authentication?
Thanks.
Yes, you can setup pages in your app that don't require authentication. It works exactly like you'd do with Forms Auth.
On #1: in a claims based model, your app relies on an external system to authenticate users and receives evidence that the user is valid in the form of a token. You can completely automate this (using WIF and config files), or you can explicitly trigger the authentication process. In any case, your app won't be responsible for validating legitimate users anymore. It is a responsibility that it delegates to the STS (e.g. ADFS). That's why apps are called "relying parties".
I'd suggest you read the first couple chapters of the A Guide to Claims based Identity for a better understanding of the underlying principles.

How to genreate a sts claim with default values for development and testing

We a have asp.net webform application where we use STS claims to manage user authorization. The workflow is pretty straight forward. User hits a login page enters credentials, a claim is generated which contains their rights. This claim is used to pass rights to our applications WCF service to control what data they have access to etc. For automated testing (and even development) I would like to setup a mechanism where the automated test bypasses the login and a dummy claim with the appropriate criterion is is used on page load. I would like to accomplish this without re-writing the existing sts service. Does anyone know if it is possible to create a dummy claim and when the main site is call inject this into document. I feel comfortable with working around the authentication (isAuthenticated) but I'm not sure about the claim for authorization. I'd appreciate any suggestions or hints on where to look/read up on creating a development/stub claim.
thanks in advance,
Not sure what the best place for injection in your code is, but you can always create ClaimsIdentity/ClaimsPrincipal yourself with any claims you want.

Integrating 2 different user dbs into a single ASP.NET MVC membersip provider?

I'm working on a project that needs to authenticate users based on records in two different databases. All administrators are stored locally and require full functionality to manage their accounts (reset password, etc). Regular users are authenticated against a different database used by another web app, so I only need to check that their credentials are correct.
After entering their username/pass at the logon screen, my app should check if they exist in the local admins table. If so, they are given the role of 'admin' and allowed access. If not, it should then check the other app's user table and give them a 'user' role if successful.
The project is basically a large online book. Users simply need authentication to view it, rate the sections, and bookmark pages. The rating/bookmark data will be associated with their unique id. All user management is handled in the external app. Admins, however, will only be able to view/edit the pages and will NOT be rating/bookmarking things. Their accounts will be managed with this admin area.
What is the best way to accomplish this in a .NET MVC application? By 'this', I mean integrating the logon/authentication system with both and assigning them a role based on which database confirms their credentials.
Thanks in advance!
MVC really doesn't have much to do with your user validation logic - you'll need to implement a custom membership provider to handle connecting to both databases and performing the validation. This membership class could be ported to any application though, it's not specific to MVC.
Once you've got your logic in your custom membership provider, you just need to use FormsAuthentication with your MVC app, of which there are lots of tutorials around, here's a quick one.
The only tip that I would add that pertains to MVC is that you should try to keep your logic for view decisions in your controllers. It's tempting to put something like "<% if user == admin then renderPartial(this) else renderPartial(that) %>" in your View, but that violates MVC principles in my opinion. Much better to use ViewModels or populate ViewData in your controller.

Setting ASP.Net Role Provider Programmatically

I have a requirement for multiple Role Providers per website. What I'm not seeing is if/how to tell ASP.Net which provider to use (similar to the membership provider property on the login controls). I have a feeling that since this is done (I beleive) in an HTTP Module the role check may be occuring before the page life cycle ever begins - but I'm hoping someone gives me a different answer.
If I want to have multiple providers per website am I going to have to junk the configuration in web.config and perform the checks manually?
The Providers property references all the role providers enabled for an application. You can control which provider you wish to use at runtime like this:
RoleProvider provider = Roles.Providers["MyRoleProvider"];

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