Authorize Error - ASP.NET Web API with Token based authorization and Roles

Question

I am using Web API 2 with OWIN token based authentication. All is going well except authorization based on Roles.

Here is my controller:

[Authorize(Roles = "Admin")]
[RoutePrefix("api/Account")]   
public class AccountController : ApiController
{
    ..............

    // POST api/Account/Register
    //[AllowAnonymous]
    [Route("Register")]
    public async Task<IHttpActionResult> Register(AppUser user)
    {
      ...............

The problem is the following: I logged in my application with a user that has role Admin but I get unauthorized error 401 when trying to register. I already rectified that the AspNetUser that I am using to log in is an Admin in AspNetUserRoles table.

Here is my GrantResourceOwnerCredentials method:

public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
    {

        context.OwinContext.Response.Headers.Add("Access-Control-Allow-Origin", new[] { "*" });

        using (AuthRepository _repo = new AuthRepository(new GloboStudioUniversityContext()))
        {
            IdentityUser user = await _repo.FindUser(context.UserName, context.Password);

            if (user == null)
            {
                context.SetError("invalid_grant", "The user name or password is incorrect.");
                return;
            }


        }

        var identity = new ClaimsIdentity(context.Options.AuthenticationType);
        identity.AddClaim(new Claim("sub", context.UserName));
        //identity.AddClaim(new Claim("role", "user"));
        identity.AddClaim(new Claim(ClaimTypes.Role, "Admin"));
        identity.AddClaim(new Claim(ClaimTypes.Role, "Student"));
        identity.AddClaim(new Claim(ClaimTypes.Role, "Candidate"));

        context.Validated(identity);

    }

Answer 1

Can you check to see if the "Admin" claims is resolved in your api method ...

var identity = User.Identity as ClaimsIdentity;
var claim = identity.Claims.FirstOrDefault(c => c.Type == ClaimTypes.Role && c.Value == "Admin");

if (claim == null) {
  //Raise 401
}

The Authorize attribute does not understand claims. It looks for Admin as a role, so it invokes "User.IsInRole" method of the IPrincipal interface.

In order for this work you would need to add the claims as roles in your owin pipeline and assign to HttpContext.Current.User.