How can I implement permission-based authorization in ASP.NET? - asp.net

I'm working an a ASP.NET application (not using MVC) and need a User-Role-Permission based authorization scheeme, where pages and/or methods can demand the specific permission they require (instead of which role the user has). Is there a way to extend Forms Authentication (or building something) to solve this?
If possible I would like to be able to use attributes:
[RequirePermission("UserEdit")]
public partial class EditUser : System.Web.UI.Page
{
}
Perhaps even for methods:
public class MyClass
{
...
[RequirePermission("UserEdit")]
public void Save()
{
...
}
}
Is this possible?
I found this page, that suggested using Roles for permissions:
[Authorize(Roles = "UserEdit")]
public partial class EditUser : System.Web.UI.Page
{
}
I am not very fond of this solution, but that would also be a possible way to solve things, but what do I need to do to get it working?

Microsoft's authorization model sucks...and it's widely acknowledged
http://lostechies.com/derickbailey/2011/05/24/dont-do-role-based-authorization-checks-do-activity-based-checks/).
That said. It's nice to have cross compatibility by fitting into their IPrincipal.IsInRole API (and thus being able to leverage the Authorize attribute)
So...what I do to compromise is have a full permission model in the DB with Users, Roles, and Permissions...but when my code sets the CurrentPrincipal I flatten the User's Roles and Permissions into the Roles collection of the IPrincipal. It's far from ideal...but IMHO it's a decent compromise. Others (Rockford Lhotka) have also taken this approach: http://www.lhotka.net/weblog/PermissionbasedAuthorizationVsRolebasedAuthorization.aspx

Related

ASP.NET Identity - Steps for custom authentication

Envrionment: Visual Studio 2013, ASP.NET MVC 5
On the new MVC5-based project I will be working on, I need to use a custom database that stores usernames, passwords, and roles in its own way. I am searching the Internet to look for an example for custom authentication. Looks like the old-style "membership provider" classes have been replaced by the new "Identity" mechanism.
However, finding a good step-by-step example has proven to be futile. There are a few links (published this year) that talk about implementing custom IPrincipal and DbContext classes. Some other links talk about implementing IUserLoginStore and IUserPasswordStore. A few others hinted on implementing IUser, IUserStore interfaces.
Maybe the last option is what is needed. Can someone please guide me with the steps or point me to any link that has a simple example? Something like:
Implement MyUser based on IUser
Implement MyUserStore based on IUserStore
Modify web.config to use MyUserStore
Remove DefaultConnection from web.config as it is not required
Regards.
First, stop. Stop thinking about "custom authentication". You don't need custom authentication, you just need custom storage of authentication data.
ASP.NET Identity has abstracted out the storage mechanism of authentication from the process of authentication. There are several interfaces that follow the pattern IxxxStore.. Such as IUserStore, IRoleStore, etc...
You can find more information about this here, along with custom implementations for various databases which you can probably convert to your own needs.
http://odetocode.com/blogs/scott/archive/2014/01/20/implementing-asp-net-identity.aspx
As an example, here is a RavenDB implementation that uses all the various interfaces in a single class.
https://github.com/tugberkugurlu/AspNet.Identity.RavenDB/blob/master/src/AspNet.Identity.RavenDB/Stores/RavenUserStore.cs
However, all this assumes you really truly a need to store data totally differently. If you just need to store the data in different columns, then it may simply be as easy as overriding OnModelCreating in your IdentityContext and changing the names of the columns in use.
ad.1.
public class ApplicationUser :IUser
{
public string Id
{
get;
set;
}
public string UserName
{
get;
set;
}
}
ad.2.
public class MyStore : IUserStore<ApplicationUser>, IUserPasswordStore<ApplicationUser>, IUserSecurityStampStore<ApplicationUser>, IUserEmailStore<ApplicationUser>
{
... //implement all interfaces here
}
ad. 3.
Now you can create your applicationUserManagerService (you will need IdentityMessageService, and IDataProtectionProvider):
var applicationUserManagerService = new ApplicationUserManagerService(new MyStore(), emailService, dataProtectionProvider);
Try to use IoC and register your IUserStore (I did it this way - link below):
unityContainer.RegisterType<IUserStore<ApplicationUser>, MyStore>();
check also my answer here (i'm using int as UserId there):
AspIdentiy ApplicationUserManager is Static, how to extend so it participates in my IoC framework?

asp.net MVC 4 with Data Access Layer using Entity Framework 5?

In my project, i have first created my Data Access Layer using Entity Framework with the following projects in a single solution,
1.Domain Model - Entity Model (.edmx)
2.Services - Business Services, Dtos, Infrastructure(Configurator), Interfaces and Models(Repository)
Now the problem is, i want to connect this data access layer to my MVC project, i do not know how to make the data access layer projects to behave as the models for my mvc project. So can anyone tell me how to connect my data access layer into my controllers and views.. any references is appreciated. Thanks in Advance !
I think what you're asking is what's the best way for controllers to interact with your services and data layer?
One option is to use the mediator pattern, and decouple the services from the controllers.
There's a great implementation for ASP.NET MVC apps: ShortBus, also available on nuget that I've used in a number of projects, and so far it's worked great.
One of the nice things about ShortBus is it's support for dependency injection. In the example below, all the services are created with Ninject, and require the appropriate registration.
The basic idea is you define queries and commands that the controllers will use, and then add handlers to perform the actual work.
public class AddUser : ICommand<User>
{
public string Email { get; set; }
}
and then a handler:
public class AddUserHandler : ICommandHandler<AddUser, User>
{
private IDatabaseService _database;
private IEmailService _email;
public AddUserHandler(IDatabaseService database, IEmailService email)
{
_database = database;
_email = email;
}
public User Handle(AddUser command)
{
bool created = _database.CreateUser(command.Email);
if (created)
{
_email.SendWelcome(command.Email);
}
}
}
Then inside your controller, all you'd do is issue the command:
public class UsersController : Controller
{
private IMediator _mediator;
public UsersController(IMediator mediator)
{
_mediator = mediator;
}
public ActionResult Create(string email)
{
User user = _mediator.Send(new AddUser("foo#bar.com"));
}
}
The things I like about this pattern are:
Controllers don't need to know how to create a user. It issues a command, and the appropriate business logic handles it.
Each handler can require the services it needs. There's no need to pollute the controllers with services only used by a single action.
It's really easy to unit test. I use a mock, and only need to verify that _mediator.Send() was called with the correct parameters. Then to test the handler, I mock IDatabaseService and IEmailService and verify they are called correctly in the 2 cases.
Commands and queries can be reused, and again, the caller never needs to know what's required to handle the request.
As for the Views, I'd recommend ViewModels.
Each View gets it's own ViewModel, which holds whatever is required for showing that particular page. You'd then map your domain objects to their own individual ViewModels, possibly with AutoMapper.
What's nice about ViewModels is you can format the data appropriately (formatting a DateTime maybe), and then your Views don't need any special logic. If later you decide to update the DateTime format, you only need to change it in one place.
Create a (shared) interface to pass to the layer that's between the DAL and MVC, especially if you're unit testing. Use a repository pattern. Check it out here:
http://csharppulse.blogspot.com/2013/09/learning-mvc-part-5repository-pattern.html
This should get you going...

Custom authorization in ASP.NET as filter or in controller's constructor?

In my ASP.NET Web API controller, I want to restrict access to those in the User role. The common way to do this is to extend the AuthorizeAttribute (example, example) and then sprinkle my controllers with my custom attribute (e.g. [AuthorizeUser]).
Another way to do this is to add a function in the controller's constructor. The constructor is required anyway because I'm using dependency injection.
Here's some code:
public class MyController: ApiController
{
private IUnitOfWork unitOfWork;
private IAccountUtils accountUtils;
// Constructor
public MyController(
IUnitOfWork unitOfWork,
IAccountUtils accountUtils)
{
this.unitOfWork = unitOfWork;
this.accountUtils = accountUtils;
// Restrict access to 'User' role
accountUtils.ThrowExceptionIfUserNotInRole(User.Identity, "User");
}
// More code
}
Because there are countless tutorial and examples of using a filter to authorize users I assumed that was the best way to go. However, when I stepped through my code in the debugger I found that the constructor method gets fired BEFORE the filter.
To optimize code, it makes sense to break as soon as possible if the user is not authorized to access the controller. If I'm not mistaken, then, it should be more efficient to perform authorization in the constructors instead of in a filter. Am I correct or am I missing something here?
It seems like your main concern is optimizing your code, and you're correct to note that the controller constructor runs before the authorization filter. But the difference in performance between those two solutions is extremely small and shouldn't really impact your service.
While throwing from a constructor might work, it's not the most elegant solution because it requires you to authorize in code rather than declaratively with an attribute. It also forces you to mix object instantiation logic with authorization logic which isn't as clean.
So I'd recommend just sticking to using an authorization filter for this one.

custom membership provider asp.net

I have a website that is already built using the default aspnet membership provider. I am looking to expand it in order to slightly modify the functions.
From my understanding, I would want to create a custom membership provider inheriting from the membership class, and then overload the functions. I got that far, but I was unable to figure out how to call the original validate user.
My goal was to change the validate user to something like...
public override bool ValidateUser(string userName, string password)
{
if(base.ValidateUser(userName, password))
{
\\Write to database that User logged in
return true;
}
return false;
}
However, when I tried that, base.ValidateUser(x,y) threw errors. How would I go about achieving what I want to?
My guess is that you have inherited from the abstract MembershipProvider class. If this is so then calling the base class method is of course impossible as there is no implementation in the abstract class.
If, on the other hand, you want to call a base class method, you have to inherit from proper base class, like the SqlMembershipProvider.

Switch to SQL membership provider from AD membership provider runtime

In my asp.net application admin functionality, I am trying to combine AD authentication and form authorization for creating the users, roles and Assign users to roles etc. I have configured MembershipADProvider and AspNetSqlMembershipProvider in my web.config with MembershipADProvider as the default one. After user logs in using AD authentication, I need to switch/assign my membership object to use AspNetSqlMembershipProvider in order to get all the users from membership object (from dbo.aspnet_Users table). How do I switch the provider during run time? I have tried different approaches after searching for this issue and none of that seem to work for me so far.
Here are couple of approaches I tried:
1. foreach (MembershipProvider mp in Membership.Providers)
{
if (mp.Name == "MembershipADProvider")
{
Membership.Providers.Remove(MembershipADProvider");
MembershipUserCollection users = Membership.GetAllUsers();
ddlUsers.DataSource = users;
ddlUsers.DataBind();
break;
}
}
Membership.Providers.Remove(MembershipADProvider"); - doesn't work as it's not supported..
Also, tried to clear the Membership.Providers and then add only the type of AspNetSqlMembershipProvider which are also not supported.
I can't set Membership.Provider with value from
Membership.Providers["AspNetSqlMembershipProvider"] as Membership.Provider is a read only property.
I tried to swtich the connection string between 2 providers, which didn't swtich the provider, as both are different types of providers..if both were sqlserver providers this would have worked I believe.
Please let me know if anybody has successfully implemented or if at all this is a plausible approach. Thank You!
You would pass an explicit provider to your code, rather than taking a dependency on Memebership directly (which just wraps the one flagged as default in the config). There is no need to swap them in and out at runtime, think how this would affect thread safety.
So rather than saying Membership.GetAllUsers(); you would do something like (I don't have a compiler to hand):
public UserSerivce : IUserService
{
private MembershipProvider provider;
public UserService(MembershipProvider provider)
{
this.provider = provider;
}
public IEnumerable<MembershipUser> GetUsers()
{
return provider.GetAllUsers();
}
public void DoSomethingElseUseful()
{
...
}
}
And then to use it for a particular provider:
var service = new UserService(Membership.Providers["mySqlMembershipProvider"]);
var users = service.GetUsers();
Or if using AD specific code:
var service = new UserService(Membership.Providers["myADMembershipProvider"]);
var users = service.GetUsers();
Using DI in this way also helps keep code testable.
If all you need a list of users in the aspnet_Users table, just connect to your database with System.Data.SqlClient objects and query the table. There is no reason (that you mentioned) you need to use a membership provider to get that data.
Having said that, your membership/authentication scheme sounds like it may have some design issues, perhaps best tackled in a different question, but I think it might be useful to you if you sought comment on what you are trying to accomplish overall with the multiple membership providers.
Edit: I found some potentially useful posts on using multiple membership providers. It looks like the general idea is to implement custom code handling the Login.Authenticate event on your Login control, and use Membership.Providers["ProviderName"].ValidateUser to attempt authentication with each provider.
http://www.stevideter.com/2008/03/20/using-two-membership-providers-for-aspnet-logins/
http://forums.asp.net/p/1112089/1714276.aspx

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