I've set up a simple policy based authorization for testing purposes. The authorization works, as it breaks inside the handler. If I set the test authorization to pass, I'm allowed to access the controller endpoint I set to use the TestPolicy. However, if I set it to fail like in the code snippet below, the authorization fails, but I get a 500-response where clearly a 401 or 403 would be appropriate.
I'm fairly sure it's because the API doesn't have any form of authentication. But I do not want to implement any authentication in this API, as all calls to it should be treated as if they are authenticated. Roles etc. will be fetched through the httpcontext. Does anyone know how I can address this problem without requiring the API consumer to authenticate themselves?
The test code is below. The parameter to new TestRequirement() can be changed to test passing/failing authorization easily.
public static void Configure(IServiceCollection services, IConfiguration configuration)
{
services.AddAuthorization(options =>
{
options.AddPolicy("TestPolicy",
policy => policy.Requirements.Add(new TestRequirement(false)));
});
services.AddSingleton<IAuthorizationHandler, TestHandler>();
//<snip>
}
public class TestHandler : AuthorizationHandler<TestRequirement>
{
/// <inheritdoc />
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, TestRequirement requirement)
{
if (requirement.Passes)
{
context.Succeed(requirement);
}
return Task.CompletedTask;
}
}
public class TestRequirement : IAuthorizationRequirement
{
public bool Passes { get; }
public TestRequirement(bool shouldPass)
{
this.Passes = shouldPass;
}
}
Edit: I ended up making a custom authenticationhandler, like this:
public class AuthenticationSchemeHandler : IAuthenticationHandler
{
private HttpContext httpContext;
/// <inheritdoc />
public Task<AuthenticateResult> AuthenticateAsync()
=> Task.FromResult(AuthenticateResult.NoResult());
/// <inheritdoc />
public Task ChallengeAsync(AuthenticationProperties properties)
{
properties ??= new AuthenticationProperties();
this.httpContext.Response.StatusCode = (int) HttpStatusCode.Unauthorized;
return Task.CompletedTask;
}
/// <inheritdoc />
public Task ForbidAsync(AuthenticationProperties properties)
{
properties ??= new AuthenticationProperties();
this.httpContext.Response.StatusCode = (int) HttpStatusCode.Forbidden;
return Task.CompletedTask;
}
/// <inheritdoc />
public Task InitializeAsync(AuthenticationScheme scheme, HttpContext context)
{
this.httpContext = context;
return Task.CompletedTask;
}
}
It seems to work (although it feels kinda wrong to implement and use authentication when I don't actually authenticate anything), however when my testhandler fails, it'll call the challengeasync instead of forbidasync. From my understanding challengeasync is for when you do not know the user and need to verify them, while forbidasync is when the use is unauthorized. So just scratching my head a bit.
Related
I have ASP.NET Core MVC application using NET 5. Only authenticated users are allowed to access the application. The authorization policy below takes care of it.
public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews(options =>
{
var authorizationPolicy = new AuthorizationPolicyBuilder()
.RequireClaim(ClaimTypes.Email)
.RequireClaim(ClaimTypes.NameIdentifier)
.RequireClaim(ClaimTypes.Name)
.RequireClaim(IdentityClaimTypes.IdToken)
.RequireAuthenticatedUser()
.Build();
options.Filters.Add(new AuthorizeFilter(authorizationPolicy));
})
}
The controllers are also using AuthorizeRoles attribute to check access based on roles.
public class AuthorizeRolesAttribute : AuthorizeAttribute
{
public AuthorizeRolesAttribute(params string[] roles) : base()
{
if (roles.Length > 0)
{
Roles = string.Join(",", roles);
}
}
}
[AuthorizeRoles("ClientAdmin")]
public class WorkItemClientsController : BaseController
{
private readonly IClientWorkItemService _clientWorkItemService;
public WorkItemClientsController(IClientWorkItemService clientWorkItemService)
{
_clientWorkItemService = clientWorkItemService;
}
[HttpGet]
[Route("workitems/{workItemID}/clients")]
public async Task<ActionResult> Index([FromRoute(Name = "workItemID")] int workItemID)
{
}
}
The application has few actions that need to be further authorized based on the user's data in the database. I have the following
public class WorkItemRequirement : IAuthorizationRequirement
{
}
public class WorkItemAuthorizationHandler : AuthorizationHandler<WorkItemRequirement>
{
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, WorkItemRequirement requirement)
{
//check if logged in user can access this route based on workitemid from the route, if true then return context.Succeed(requirement);
}
}
public class WorkItemAuthorizeAttribute : AuthorizeAttribute
{
public WorkItemAuthorizeAttribute()
{
Policy = "WorkItemPolicy"
}
}
I will add WorkItemAuthorizeAttribute to require action methods.
What I am missing here is how WorkItemAuthorizeAttribute will know which handler to invoke. In this case its WorkItemAuthorizationHandler.
What do I need to change/add in AuthorizationPolicyBuilder in startup.cs to make this association?
Pretty much everything you can find in official docs here
basically as you said you need to modify your policy to include your WorkItemRequirement like that:
.Requirements.Add(new WorkItemRequirement());
That will 'glue' Policy in your Attribute with your AuthorizationHandler
I have web API with custom policies and authorization handlers.
I wanted to reuse authorization handlers but HttpContext is null when attribute is used on signalr's hub.
For example this is my controller.
[Authorize]
public sealed class ChatsController : ControllerBase
{
[HttpPost("{chatId}/messages/send")]
[Authorize(Policy = PolicyNames.ChatParticipant)]
public Task SendMessage() => Task.CompletedTask;
}
And this my my authorization handler. I can extract "chatId" from HttpContext and then use my custom logic to authorize user.
internal sealed class ChatParticipantRequirementHandler : AuthorizationHandler<ChatParticipantRequirement>
{
private readonly IHttpContextAccessor _httpContextAccessor;
public ChatParticipantRequirementHandler(IHttpContextAccessor httpContextAccessor)
{
_httpContextAccessor = httpContextAccessor;
}
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, ChatParticipantRequirement requirement)
{
if(_httpContextAccessor.HttpContext != null)
{
// Logic
}
return Task.CompletedTask;
}
}
However this won't work with Azure SignalR because I don't have access to HttpContext. I know that I can provide custom IUserIdProvider but I have no idea how to access "chatId" from "Join" method in my custom authorization handler.
[Authorize]
public sealed class ChatHub : Hub<IChatClient>
{
[Authorize(Policy = PolicyNames.ChatParticipant)]
public async Task Join(Guid chatId)
{
await Groups.AddToGroupAsync(Context.ConnectionId, chatId.ToString());
}
Is it possible to reuse my authorization handlers?
I would like to avoid copypasting my code.
One solution is to extract my authorization code to separate services but then I have to manually call those from my hubs and abandon [Authorize] way.
Your chat is a resource, and you want to use resource based authorization. In this case declarative authorization with an attribute is not enough, because chat id is known at runtime only. So you have to use imperative authorization with IAuthorizationService.
Now in your hub:
[Authorize]
public sealed class ChatHub : Hub<IChatClient>
{
private readonly IAuthorizationService authService;
public ChatHub(IAuthorizationService authService)
{
this.authService = authService;
}
public async Task Join(Guid chatId)
{
// Get claims principal from authorized hub context
var user = this.Context.User;
// Get chat from DB or wherever you store it, or optionally just pass the ID to the authorization service
var chat = myDb.GetChatById(chatId);
var validationResult = await this.authService.AuthorizeAsync(user, chat, PolicyNames.ChatParticipant);
if (validationResult.Succeeded)
{
await Groups.AddToGroupAsync(Context.ConnectionId, chatId.ToString());
}
}
}
Your authorization handler should look different, because it needs the chat resource in its signature to do this kind of evaluation:
internal sealed class ChatParticipantRequirementHandler : AuthorizationHandler<ChatParticipantRequirement, Chat>
{
private readonly IHttpContextAccessor _httpContextAccessor;
public ChatParticipantRequirementHandler(IHttpContextAccessor httpContextAccessor)
{
_httpContextAccessor = httpContextAccessor;
}
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, ChatParticipantRequirement requirement, Chat chat)
{
// You have both user and chat now
var user = context.User;
if (this.IsMyUserAuthorizedToUseThisChat(user, chat))
{
context.Succeed(requirement);
}
else
{
context.Fail();
}
return Task.CompletedTask;
}
}
Edit: there is actually another option I didn't know about
You can make use of HubInvocationContext that SignalR Hub provides for authorized methods. This can be automatically injected into your AuthorizationHandler, which should look like this:
public class ChatParticipantRequirementHandler : AuthorizationHandler<ChatParticipantRequirement, HubInvocationContext>
{
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, ChatParticipantRequirement requirement, HubInvocationContext hubContext)
{
var chatId = Guid.Parse((string)hubContext.HubMethodArguments[0]);
}
}
Hub method will be decorated normally with [Authorize(Policy = PolicyNames.ChatParticipant)]
You still will have two authorization handlers, AuthorizationHandler<ChatParticipantRequirement> and AuthorizationHandler<ChatParticipantRequirement, HubInvocationContext>, no way around it. As for code dublication, you can however just get the Chat ID in the handler, either from HttpContext or HubInvocationContext, and than pass it to you custom written MyAuthorizer that you could inject into both handlers:
public class MyAuthorizer : IMyAuthorizer
{
public bool CanUserChat(Guid userId, Guid chatId);
}
In a WebAPI .net core project I have created a Middleware class that validates an api key. From validating it, it retrieves the permissions that the key has (user or admin) within the invoke method.
I pass it through a switch to set the principle like so
GenericIdentity identity = new GenericIdentity("API");
GenericPrincipal principle = null;
//we have a valid api key, so set the role permissions of the key
switch (keyValidatorRes.Role)
{
case Roles.User:
principle = new GenericPrincipal(identity, new[] { "User" });
context.User = principle;
break;
case Roles.Admin:
principle = new GenericPrincipal(identity, new[] { "Admin" });
context.User = principle;
break;
default:
principle = new GenericPrincipal(identity, new[] { "Other" });
context.User = principle;
break;
}
On controllers methods I have
[Authorize(Roles = "Admin")]
to validate the roles of an authenticated api key
If the user has the admin principle it goes through as expected. However, if it has a user or other principle then I get an error about
not having a DefaultForbidScheme
I googled around and added Authentication to my startup.cs with a customer scheme
services.AddAuthentication(options=> {
options.DefaultForbidScheme = "forbidScheme";
options.AddScheme<AuthSchemeHandle>("forbidScheme", "Handle Forbidden");
});
and created the AuthSchemeHandle
public class AuthSchemeHandle : IAuthenticationHandler
{
private HttpContext _context;
public Task<AuthenticateResult> AuthenticateAsync()
{
return Task.FromResult(AuthenticateResult.NoResult());
}
public Task ChallengeAsync(AuthenticationProperties properties)
{
throw new NotImplementedException();
}
public Task ForbidAsync(AuthenticationProperties properties)
{
return Task.FromResult(AuthenticateResult.Fail("Failed Auth"));
}
public Task InitializeAsync(AuthenticationScheme scheme, HttpContext context)
{
_context = context;
return Task.CompletedTask;
}
}
Now if the principle does not have Admin it fails without the error but the response that is returned on the API is 200 with no content. I was expecting a 4xx response with the message "Failed Auth"
I am just trying to work out why it is not as expected as although it seems "fixed" I do not understand how it has fixed it.
Is there a better way that I should be doing this?
why it is not as expected as although it seems "fixed" I do not understand how it has fixed it.
There's no dark magic when the authentication handler calls IAuthenticationHandler.ForbidAsync() method. We have to do relevant things ourself. In short, setting the StatusCode=403 as your need.
public async Task ForbidAsync(AuthenticationProperties properties)
{
properties = properties ?? new AuthenticationProperties();
_context.Response.StatusCode = 403;
// ...
return Task.CompletedTask;
}
As a side note, you don't need return a Task.FromResult() as it doesn't care about the result.
Is there a better way that I should be doing this?
The ASP.NET Core Team provides us an abstract class AuthenticationHandler to handle authentication. This abstract class has a built-in implementation for ForbidAsync(AuthenticationProperties properties) (and also for other public methods). So it's much easy to extends this abstract class as below:
public class MyAuthenticationHandler : AuthenticationHandler<AuthenticationSchemeOptions>
{
public MyAuthenticationHandler(IOptionsMonitor<AuthenticationSchemeOptions> options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock)
: base(options, logger, encoder, clock)
{
}
protected override async Task<AuthenticateResult> HandleAuthenticateAsync()
{
return AuthenticateResult.NoResult();
}
}
Finally, add a configuration for authentication service:
services
.AddAuthentication(options=>{
options.DefaultAuthenticateScheme = "forbidScheme";
options.DefaultForbidScheme = "forbidScheme";
options.AddScheme<MyAuthenticationHandler>("forbidScheme", "Handle Forbidden");
});
It should work as expected.
I am working on a website where I need to authorize the user through a service. I have managed to get windows authentication working if I use the AuthorizeAttribute (User.Identities will be set). My plan is to create a custom middleware that sets the roles/claims for the user but context.User is not set in the middleware. User.Identities will also not be set in the controllers where I don't add the AuthorizeAttribute.
My goal is to write a middleware that gets the windows username and calls a service with the username to get the roles the user has access to and then set the roles or claims for the user.
public class RoleMiddleware
{
private readonly RequestDelegate _next;
public RoleMiddleware(RequestDelegate next)
{
_next = next;
}
public async Task Invoke(HttpContext context)
{
if (!rolesSet)
{
var result = _service.GetRoles(context.User.Identity.Name);
//set roles
//set claims
}
await _next.Invoke(context);
}
}
Would a middleware be the correct place to do this and what do I need to do to get access to the username in the same way as I do when I use the AuthorizeAttribute in a controller?
In my opinion that's not the right way to do it. ASP.NET Identity provide rich set of classes which you can override and extend to fit your requirements.
If you want to inject roles bases on some custom service then you should override RoleStore (and maybe RoleManager too) and inject there your custom roles.
It will be also worth to take a look here: Using Role Claims in ASP.NET Identity Core
I solved it by using requirements
public class CustomFunctionRequirement : IAuthorizationRequirement
{
public CustomFunctionRequirement(string function)
{
Function = function;
}
public string Function { get; }
}
The handler
public class CustomFunctionHandler : AuthorizationHandler<CustomFunctionRequirement>
{
private readonly Service _service;
public CustomFunctionHandler(Service service)
{
_service = service;
}
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, CustomFunctionRequirement requirement)
{
var functions = _service.GetFunctions(context.User.Identity.Name);
if (functions.Any(x => x == requirement.Function))
{
context.Succeed(requirement);
}
return Task.CompletedTask;
}
}
Setup in ConfigureServices in Startup
services.AddMvc(
config =>
{
var policy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser()
.Build();
config.Filters.Add(new AuthorizeFilter(policy));
});
services.AddAuthorization(
options =>
{
options.AddPolicy("User", policy => policy.Requirements.Add(new CustomRequirement("User")));
});
I can now in my controller specify the requirement by adding the authorize attribute [Authorize(Policy = "User")].
I'm moving from ASP.Net Framework to ASP.Net Core.
In ASP.Net Framework with Web API 2 project, I can customize AuthorizeAttribute like this :
public class ApiAuthorizeAttribute : AuthorizationFilterAttribute
{
#region Methods
/// <summary>
/// Override authorization event to do custom authorization.
/// </summary>
/// <param name="httpActionContext"></param>
public override void OnAuthorization(HttpActionContext httpActionContext)
{
// Retrieve email and password.
var accountEmail =
httpActionContext.Request.Headers.Where(
x =>
!string.IsNullOrEmpty(x.Key) &&
x.Key.Equals("Email"))
.Select(x => x.Value.FirstOrDefault())
.FirstOrDefault();
// Retrieve account password.
var accountPassword =
httpActionContext.Request.Headers.Where(
x =>
!string.IsNullOrEmpty(x.Key) &&
x.Key.Equals("Password"))
.Select(x => x.Value.FirstOrDefault()).FirstOrDefault();
// Account view model construction.
var filterAccountViewModel = new FilterAccountViewModel();
filterAccountViewModel.Email = accountEmail;
filterAccountViewModel.Password = accountPassword;
filterAccountViewModel.EmailComparision = TextComparision.Equal;
filterAccountViewModel.PasswordComparision = TextComparision.Equal;
// Find the account.
var account = RepositoryAccount.FindAccount(filterAccountViewModel);
// Account is not found.
if (account == null)
{
// Treat the account as unthorized.
httpActionContext.Response = httpActionContext.Request.CreateResponse(HttpStatusCode.Unauthorized);
return;
}
// Role is not defined which means the request is allowed.
if (_roles == null)
return;
// Role is not allowed
if (!_roles.Any(x => x == account.Role))
{
// Treat the account as unthorized.
httpActionContext.Response = httpActionContext.Request.CreateResponse(HttpStatusCode.Forbidden);
return;
}
// Store the requester information in action argument.
httpActionContext.ActionArguments["Account"] = account;
}
#endregion
#region Properties
/// <summary>
/// Repository which provides function to access account database.
/// </summary>
public IRepositoryAccount RepositoryAccount { get; set; }
/// <summary>
/// Which role can be allowed to access server.
/// </summary>
private readonly byte[] _roles;
#endregion
#region Constructor
/// <summary>
/// Initialize instance with default settings.
/// </summary>
public ApiAuthorizeAttribute()
{
}
/// <summary>
/// Initialize instance with allowed role.
/// </summary>
/// <param name="roles"></param>
public ApiAuthorizeAttribute(byte[] roles)
{
_roles = roles;
}
#endregion
}
In my customized AuthorizeAttribute, I can check whether account is valid or not and return HttpStatusCode with message to client.
I'm trying to do the samething in ASP.Net Core, but no OnAuthorization for me to override.
How can I achieve the same thing as in ASP.Net Framework ?
Thank you,
You're approaching this incorrectly. It never was really encouraged to write custom attributes for this, or to extend existing. With ASP.NET Core roles are still apart of the system for backwards compatibility but they are now also discouraged.
There is a great 2 part series on some of the driving architecture changes and the way that this is and should be utilized found here. If you want to still rely on roles you can do so, but I would suggest using policies.
To wire a policy do the following:
public void ConfigureServices(IServiceCollection services)
{
services.AddAuthorization(options =>
{
options.AddPolicy(nameof(Policy.Account),
policy => policy.Requirements.Add(new AccountRequirement()));
});
services.AddSingleton<IAuthorizationHandler, AccountHandler>();
}
I created a Policy enum for convenience.
public enum Policy { Account };
Decorate entry points as such:
[
HttpPost,
Authorize(Policy = nameof(Policy.Account))
]
public async Task<IActionResult> PostSomething([FromRoute] blah)
{
}
The AccountRequirement is just a placeholder, it needs to implement the IAuthorizationRequirement interface.
public class AccountRequirement: IAuthorizationRequirement { }
Now we simply need to create a handler and wire this up for DI.
public class AccountHandler : AuthorizationHandler<AccountRequirement>
{
protected override Task HandleRequirementAsync(
AuthorizationHandlerContext context,
AccountRequirement requirement)
{
// Your logic here... or anything else you need to do.
if (context.User.IsInRole("fooBar"))
{
// Call 'Succeed' to mark current requirement as passed
context.Succeed(requirement);
}
return Task.CompletedTask;
}
}
Additional Resources
ASP.NET Core Security -- All the things
My comment looks bad as a comment so I post an answer but only useful if you use MVC:
// don't forget this
services.AddSingleton<IAuthorizationHandler, MyCustomAuthorizationHandler>();
services
.AddMvc(config => { var policy = new AuthorizationPolicyBuilder()
.RequireAuthenticatedUser() .AddRequirements(new[] { new MyCustomRequirement() })
.Build(); config.Filters.Add(new AuthorizeFilter(policy)); })
I also noticed that async keyword is superfluous for "HandleRequirementAsync" signature, in question code. And I guess that returning Task.CompletedTask could be good.