How are ASP.NET Roles used with Authorization?

Question

I'm using ASP.NET Core and hosting what is basically the default template with Windows Authentication enabled. I'm hosting this on a dedicated IIS server, and have verified the app is receiving correct information from AD and it correctly authenticates my session.

I feel like I'm trying to do something very simple. If the user is in the security group (from AD) "Admin" they are able to access a specific function. If they aren't in that group they do not get access.

I slapped on the [Authorize] attribute to the service

(in ConfigureServices)
services.AddAuthentication(IISDefaults.AuthenticationScheme);
(in Configure)
app.UseAuthorization();

(in service)
[Authorize]
public class SiteService
    {
        private readonly string _route;
        private readonly HttpClient _httpClient;

        public SiteService(HttpClient httpClient)
        {
            _httpClient = httpClient;
            _route = httpClient.BaseAddress.AbsoluteUri;
        }

        public async Task<IEnumerable<Site>> GetSites()
        {

        }
   }

I can see in the logs that accessing the service gives me Domain/User. I then looked up the MS Docs here: https://learn.microsoft.com/en-us/aspnet/core/security/authorization/roles?view=aspnetcore-3.1

And slapped on [Authorize(Roles = "Admin"). That worked. I then switched "Admin" with "sldkfjslksdlfkj". Nothing changed...I can still access the service.

Why is the Roles="x" check not working? How can I enable a relatively simple check to AD for a Security Group?

create a custom authorization attribute like this: https://stackoverflow.com/a/24182340/9936356 — LinkedListT, Jan 27 '20 at 21:05

score 1 · Accepted Answer · edited Jan 28 '20 at 17:09

You could write a custom Policy Authorization handlers to check all of the users' ADGroups and check if they contain the desired group name.

Refer to the following:

1.Create CheckADGroupRequirement(accept a parameter)

    public class CheckADGroupRequirement : IAuthorizationRequirement
    {
        public string GroupName { get; private set; }

        public CheckADGroupRequirement(string groupName)
        {
            GroupName = groupName;
        }
    }

2.Create CheckADGroupHandler

    public class CheckADGroupHandler : AuthorizationHandler<CheckADGroupRequirement>
    {
        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context,
                                                       CheckADGroupRequirement requirement)
        {
            //var isAuthorized = context.User.IsInRole(requirement.GroupName);

            var groups = new List<string>();//save all your groups' name
            var wi = (WindowsIdentity)context.User.Identity;
            if (wi.Groups != null)
            {
                foreach (var group in wi.Groups)
                {
                    try
                    {
                        groups.Add(group.Translate(typeof(NTAccount)).ToString());
                    }
                    catch (Exception e)
                    {
                        // ignored
                    }
                }
               if(groups.Contains(requirement.GroupName))//do the check
                {
                    context.Succeed(requirement);
                }
            }

            return Task.CompletedTask;
        }
    }

3.Register Handler in ConfigureServices

    services.AddAuthorization(options =>
    {
        options.AddPolicy("AdminOnly", policy =>
            policy.Requirements.Add(new CheckADGroupRequirement("DOMAIN\\Domain Admin")));//set your desired group name
            //other policies
    });

    services.AddSingleton<IAuthorizationHandler, CheckADGroupHandler>();

4.Use on controller/service

    [Authorize(Policy = "AdminOnly")]
    public class SiteService

How are ASP.NET Roles used with Authorization?

1 Answers1