We have two separate dotnet core apis(API1 & API2) that are protected using azure ad b2c. Both these apis are registered on the b2c tenant and have their scopes exposed. We have a client web application that is to access the above protected apis. This web app has been registered in b2c tenant and has api permissions set for the above apis with proper scopes exposed.
In a previous post about what's the best approach to configure the web app so that it is able to access multiple protected apis, an approach was suggested to "Combine both services into a single app registration and expose different scopes."
While trying to implement that, I am also to validate the scopes present in the access token along with the audience and authority.
public void ConfigureServices(IServiceCollection services)
{
services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
.AddJwtBearer(jwtOptions =>
{
//validating the access token with client id and token issuer(authority)
jwtOptions.Authority = Configuration["AzureAdB2C:Authority"];
jwtOptions.Audience = Configuration["AzureAdB2C:ClientId"];
});
services.AddMvc();
services.AddMemoryCache();
services.AddControllers();
// Start Registering and Initializing AutoMapper
services.AddAutoMapper(AppDomain.CurrentDomain.GetAssemblies());
// End Registering and Initializing AutoMappe
}
How best to validate the scopes of access token?
Any help is appreciated.
This article from Auth0 has a really nice tutorial of how to create a custom Authorize attribute that grabs the scope claim ("scp") off the token and validates the scope for each controller method. This can certainly be done more globally if you only have 1 scope per service. https://auth0.com/docs/quickstart/backend/aspnet-core-webapi/01-authorization
Related
Good Day,
Currently I have a single tenent with a React UI and .NET Core Apis secured by Azure Active Directory without any problems.
We have recently moved to a new Azure Tenent, new Active Directory etc. I have create two new App Registrations, one single App Service for UI and one for API. I have linked the App Service to AAD (UI = UI App Registration, API = API App Registration).
The problem is the API is getting a 401 error and I think see that in the original tenent the Bearer token is in a JWT format but in the new instance it's not, I believe it my be a graph api access key.
New Tenent:
Authorization: Bearer PAQABAAAAAAD--DLA3VO7QrddgJg7WevrQvEQVbZEMD8su-tIp9k2bTFUTort7SZgeDI52P6KRYefHgtmj4YrecgUKZJ2wylGuhvIzIz642n7Sg0VMU1RwKtrzWlaMqK62CaSoJcstxiEf6 *****
Orginal Tenent:
Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6Im5PbzNaRHJPRFhFSzFqS1doWHNsSFJfS1hFZyIsImtpZCI6Im5PbzNaRHJPRFhFSzFqS1doWHNsSFJfS1hFZyJ9.eyJhdWQiOiI3OThkN2ZkOC0zODk2LTQxOGMtOTQ0Ny0wNGFlNTQ2OGFkNDIiLCJpc3MiOiJodHRwczovL3N0cy53aW5kb3dzLm5ldC83ZDE3NTU3Ni03Y2Y3LTQyMDctOTA5My0wNmNiNmQyZDIwNjAvIiwiaWF0IjoxNjE2NDUyNzExLCJuYmYiOjE2MTY0NTI3MTEsImV4cCI6MTYxNjQ1NjYxMSwiYWNyIjoiMSIsImFpbyI6IkFTUUEyLzhUQUFBQU9mejhPZHp *****
Please someone kindly enought to provide some guidance / input where I am going wrong.
Regards
Paul.
When using Azure AD to obtain an access token, an additional resource parameter is required. Otherwise, the access token is not a JWT.
For example, if your web API's application ID URI is https://contoso.com/api and the scope name is Employees.Read.All, then with oidc-client the client configuration should be :
scope: 'openid profile email Employees.Read.All',
extraQueryParams: {
resource: 'https://contoso.com/api'
}
In App Service auth configuration, you can use additionalLoginParams
"additionalLoginParams": ["response_type=code", "resource=https://contoso.com/api"]
If you did not use a custom application ID URI, it may look like
api://868662dd-3e28-4c7f-b7d5-7ec02ac9c601
Quickstart: Configure an application to expose a web API
Firstly, the scope is incorrect.
You should Expose an API in your API App Registration and then add it as a permission in your UI App Registration. You can refer to this document.
And when you try to call the 'https://login.windows.net/{tenant}/oauth2/authorize endpoint, you need to specify the scope to include api://{app id of the API App Registration}. For example: api://{app id of the API App Registration} openid profile email. Then the access token would be for calling your API.
At last, for CORS issue, please configure the CORS as * in your web app to see if it helps.
Try to follow this step: Configure App Service to return a usable access token
In my experience, this problem occurs, when you try to authorize against version 1 of the endpoint.
Instead of calling
https://login.microsoftonline.com/{tenant}/oauth2/authorize
call
https://login.microsoftonline.com/{tenant}/oauth2/v2.0/authorize
You might be required to set something like "metadata URL" in you authorization library to:
https://login.microsoftonline.com/{tenant}/oauth2/v2.0/.well-known/openid-configuration
Make sure your builder follows this order...lifted from our API program.cs
These must be in order of
UseRouting -> UseAuthentication -> UseAuthorisation -> MapControllers
> app.UseRouting()
> app.UseAuthentication()
> app.UseAuthorization()
> app.MapControllers()
If app.UseAuthentication and app.UseAuthorization are not in this order in statement position you Will get 401 Unauthorised as at 01/2023 .Net 6 Core.
I have an Azure Functions API which uses Azure Active Directory authentication. I can test locally and deployed using a browser and curl calls in a process of:
Get a code
Use the code to get a token
Pass the token to authenticate and get the function result.
I now want to call this API from my Blazor WASM app but I'm sure there must be a nice MSAL call to do all the authentication but I cannot find any documentation on what that might be.
Does anyone have a code snippet to illustrate what needs to happen?
Further Information
My Azure Functions App and Blazor WASM client are not part of the same project and are hosted on different sub-domains of Azure hypotheticalapi.azurewebsites.net and hypotheticalweb.azurewebsites.net.
The web client application registration has API Permissions for the API and the API has an application registration which exposes itself with the scope that the client app has permissions for.
Again, the API and Web app work individually. I just don't seem able to get them to talk.
I have been following the "ASP.NET Core Blazor WebAssembly additional security scenarios" documentation but after several attempts I keep coming back to the error:
Microsoft.JSInterop.JSException: invalid_grant: AADSTS65001:
The user or administrator has not consented to use the application with ID 'e40aabb0-8ed5-4833-b50d-ec7ca4e07996' named 'BallerinaBlazor5Wasm'.
Send an interactive authorization request for this user and resource.
Even though I have revoked/deleted the client's permissions on the API, it has never repeated asking for consent. Is there a way I should clear the consent I previously gave? No idea how I might do that.
This GitHub Issue appears to be relevant.
I was stuck for the last two weeks with the same error code in the same setting: Blazor WASM talking to an AAD secured Azure Functions app.
What appeared to be a problem in my case was the scopes that I was listing in the http request when contacting AAD identification provider endpoints. Almost all examples I came across use Microsoft Graph API. There, User.Read is the scope that is given as an example. My first though was that even when I am contacting my own API I have to include the User.Read scope in the request because I was reasoning that this scope is necessary to identify the user. However, this is not the case and the only scope that you have to list when you call the authorize and token endpoints is the one that you exposed under the "Expose an API blade" in your AAD app registration.
I am using the OAuth2 authorization code in my example and not the implicit grant. Make sure that in the manifest of your API registration you have set "accessTokenAcceptedVersion": 2 and not "accessTokenAcceptedVersion": null. The latter implies the use of implicit flow as far as I know.
The scope the I exposed in my API is Api.Read. You can expose more scopes if you need but the point is that you only ask for scopes that you exposed.
I also have both following options unticked (i.e. no implicit flow). However, I tried with selecting "ID token" and it still worked. Note that the "ID token" option is selected by default if you let the Azure Portal create your AAD app registration from your function app Authentication blade.
Blazor code
Program.cs
This code has to be added.
builder.Services.AddScoped<GraphAPIAuthorizationMessageHandler>();
builder.Services.AddHttpClient("{NAME}",
client => client.BaseAddress = new Uri("https://your-azure-functions-url.net"))
.AddHttpMessageHandler<GraphAPIAuthorizationMessageHandler>();
builder.Services.AddScoped(sp => sp.GetRequiredService<IHttpClientFactory>()
.CreateClient("{NAME}"));
builder.Services.AddMsalAuthentication(options =>
{
builder.Configuration.Bind("AzureAd", options.ProviderOptions.Authentication);
// NOTE: no "api://" when providing the scope
options.ProviderOptions.DefaultAccessTokenScopes.Add("{you API application id}/{api exposed scope}");
});
appsetting.json
"AzureAd": {
"Authority": "https://login.microsoftonline.com/{aad tenant id}",
"ClientId": "{application id of your blazor wasm app}",
"ValidateAuthority": true
}
GraphAPIAuthorizationMessageHandler.cs
Note that this class can have a different name. you'll then also reference a different name in Program.cs.
public class GraphAPIAuthorizationMessageHandler : AuthorizationMessageHandler
{
public GraphAPIAuthorizationMessageHandler(IAccessTokenProvider provider,
NavigationManager navigationManager)
: base(provider, navigationManager)
{
ConfigureHandler(
authorizedUrls: new[] { "https://your-azure-functions-url.net" },
// NOTE: here with "api://"
scopes: new[] { "api://{you API application id}/{api exposed scope}" });
}
}
I hope this works. If not, let me know.
At least you need to get the access token, then use the token to call the function api. In this case, if you want to get the token in only one step, you could use the client credential flow, MSAL sample here, follow every part on the left to complete the prerequisites.
The following are the approximate steps(for more details, you still need to follow the sample above):
1.Create a new App registration and add a client secret.
2.Instantiate the confidential client application with a client secret
app = ConfidentialClientApplicationBuilder.Create(config.ClientId)
.WithClientSecret(config.ClientSecret)
.WithAuthority(new Uri(config.Authority))
.Build();
3.Get the token
string[] scopes = new string[] { "<AppId URI of your function related AD App>/.default" };
result = await app.AcquireTokenForClient(scopes)
.ExecuteAsync();
4.Call the function API
httpClient = new HttpClient();
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", result.AccessToken);
// Call the web API.
HttpResponseMessage response = await _httpClient.GetAsync(apiUri);
...
}
I'm working on an MVC web project which is using IdentityServer4 to authenticate users, the web app then uses an access token provided to a user by IdentityServer (authorization code flow) to call an API. The IdentityServer has been configured to use Azure AD as an external identity provider, which is the primary mechanism for users to login. That's all working great.
Once authenticated, I need to query the web app's database to determine:
If the user account is authorised to login
Retrieve claims about the user specific to the application
The IdentityServer docs (http://docs.identityserver.io/en/latest/reference/profileservice.html) suggest implementing the IProfileService interface for this, which I've done. I want the ProfileService to call the web app's API to retrieve the information about the user to avoid forcing the IdentityServer to need to know about/directly access the database. My problem however, is that calling the API though needs an access token.
Is it possible to retrieve the token for the current user inside the ProfileService's IsActiveAsync / GetProfileDataAsync methods? I can't find solid documentation that identifies if the token is even generated at that point. I'm also a total noob when it comes to authentication/authorization, it's a massive topic!
I had the idea of using the client credentials flow inside the ProfileService to call the API, just to populate that initial token. However, I don't know whether or not that's an absolutely terrible idea... or if there are any better concepts someone could refer me to that I could investigate.
Can anyone point me in the right direction?
Have a look at ITokenCreationService that is part of identityserver4. You can inject that service into your IProfileService implementation and then create a new bearer token with any claims you like.
For example:
protected readonly ITokenCreationService _tokenCreationService;
...
var token = new Token
{
AccessTokenType = AccessTokenType.Jwt,
Issuer = "https://my.identityserver.com",
Lifetime = (int)TimeSpan.FromMinutes(5).TotalSeconds,
Claims = GetClaimsNeededForApiCall()
};
string myToken = await _tokenCreationService.CreateTokenAsync(token);
...
This is not possible to retrieve the access_token for a user within ProfileService.
The profile service is called whenever IdentityServer needs to return claims about a user. This means if you try to generate a token for the user within ProfileService it will call the ProfileService again.
In a angularjs application, i use adal and adal-angular libraries to authentify user on Azure AD. On backend I use OWIN middleware in my webAPI to add custom claims with :
app.UseWindowsAzureActiveDirectoryBearerAuthentication(new WindowsAzureActiveDirectoryBearerAuthenticationOptions
{
Audience = ConfigurationManager.AppSettings["ida:Audience"],
Tenant = ConfigurationManager.AppSettings["ida:Tenant"],
Provider = new OAuthBearerAuthenticationProvider()
{
OnValidateIdentity = async context =>
{
if(!context.IsValidated)
return;
var userManager = context.OwinContext.Get<UserManager>();
string email = context.Ticket.Identity.GetClaimValue(System.Security.Claims.ClaimTypes.Email);
User user = userManager.GetByEmail(email);
context.Ticket.Identity.AddClaim(new Claim(ClaimTypes.UserId, user.Id.ToString(CultureInfo.InvariantCulture));
}
}
});
It's work for the current request, but how to add the claim in the bearer send by httpinterceptor of adal-angular for the next requests?
To answer your direct question: you cannot modify the access token, period.
It has a digital signature which will no longer be valid if you change anything in the token.
It's a security measure that prevents tampering.
Your OWIN middleware downloads the public keys of the signing key pairs from Azure AD on startup, and uses those to validate tokens.
Now if you stored your internal ids as extension attributes,
it would actually be possible to tell Azure AD to include that in the tokens.
This feature is in preview though, and not recommended for production use: https://learn.microsoft.com/en-us/azure/active-directory/develop/active-directory-optional-claims#configuring-custom-claims-via-directory-extensions.
Here you would set the internal id as an extension on the User entity, and have it included for access tokens to your API.
A pragmatic solution to your issue might be an in-memory cache.
How often do emails change?
I'm having a little trouble following how API Access delegate permissions work with azure active directory. I feel like i'm probably misunderstanding a key aspect of how AAD works.
Here is my set up
I have a Web Application let’s call it WebApp. I have created
an AAD for the Web Application and registered with a AAD App ID. Let’s
call it App ID A
I have a Web Api let’s call it ApiService. I have also created an AAD for it and registered with a AAD App ID. Let’s all it App ID B.
In AAD App ID A, I have updated the clicked on the API Access ->
Required Permissions -> Add (App ID B ; Web API) permissions
I’ve updated the manaifest in the AAD App ID B, to give consent to
knownClientApplications to include the client ID of the Web App
I’ve also enable oauth2AllowImplicitFlow to be true for both App’s
manifest.
What I’m trying to do is, A user signs into the web application sign. When it signs in, the user is able to acquire a token for the specific Web App App ID A. The user should be able to use that token and have access the Api Service with App ID B. I thought by configuring the whole API Access -> Required Permissions within the Web Application it would give me delegate permission with the logged in user to communicate with the Api Service WebApi.
When I examine the JWT token, I notice that there is a claim for Microsoft Graph, but not for the ApiService. Shouldn’t I be seeing a claim?
When I try to use the token, it reacts with a 404 authentication error.
Any advice appreciated,
Thanks,
Derek
UPDATE
In response to #joonasw
I actually looked at the example you wrote when i started.
https://joonasw.net/view/aspnet-core-2-azure-ad-authentication
In the example, the web application is initialized with:
.AddOpenIdConnect(opts =>
{
Configuration.GetSection("OpenIdConnect").Bind(opts);
opts.Events = new OpenIdConnectEvents
{
OnAuthorizationCodeReceived = ctx =>
{
return Task.CompletedTask;
}
};
});
In the HomeController, there is code to retrieve the token for the graph api
private async Task<string> GetAccessTokenAsync()
{
string authority = _authOptions.Authority;
string userId = User.FindFirstValue("http://schemas.microsoft.com/identity/claims/objectidentifier");
var cache = new AdalDistributedTokenCache(_cache, _dataProtectionProvider, userId);
var authContext = new AuthenticationContext(authority, cache);
//App's credentials may be needed if access tokens need to be refreshed with a refresh token
string clientId = _authOptions.ClientId;
string clientSecret = _authOptions.ClientSecret;
var credential = new ClientCredential(clientId, clientSecret);
var result = await authContext.AcquireTokenSilentAsync(
"https://graph.microsoft.com",
credential,
new UserIdentifier(userId, UserIdentifierType.UniqueId));
return result.AccessToken;
}
From my understanding, when the user initially login to the web application it will trigger the OnAuthorizationCodeReceived() method where it will be using the clientId/clientSecret/resource of the web applicaiton. The token is stored in the distributed token cache under the key resource/client id.
In the example, GetAccessTokenAsync() is used to grab the token to access the graph API.
In my case, I was hoping to update that method to retrieve the token for the WebApi which has a different clientId/clientSecret/resoruce. In my case, it will AcquireTokenSilentAsync will throw an AdalTokenAcquisitionExceptionFilter because the token needed is not stored in the cache and in the AdalTokenAcquisitionExceptionFilter it will call try to reauthenticate
context.Result = new ChallengeResult();
which will redirect to the authentication page and then hits the AddOpenIdConnect() method. However, the openIdConnect is configured with the web app clientID/ClientSecret/Resource and will not store the new token properly. It will try to call GetAccessTokenAsync() again and the whole process will go in an infinite loop.
In the example, if you were to comment out the "Anthentication:resource" in app.settings, you will experience the same issue with the infinite loop. What happens is that you initially authenticate correctly with no resource specified. Then when you click on you try to get the token for microsoft graph which is a new resource, it can't find it in the cache and then tries to reauthenticate over and over again.
I also notice that the acquireAsyncAuthentication only returns a AuthenticationResult with a bearer tokentype. How would you get the refresh token in this case?
Any advice?
Thanks,
Derek
UPDATE (Solution)
Thanks to #jaanus. All you have to do is update the resource to the clientid of the web api and pass that into AcquireTokenSilentAsync. The web api id uri that you can get from the azure portal did not work.
Okay, so it seems there are multiple questions here. I'll try to make some sense of this stuff to you.
Adding the "Web App"'s client id to the "ApiService" knownClientApplications is a good idea.
It allows for consent to be done for both apps at the same time. This really only matters for multi-tenant scenarios though.
Now, your Web App will be acquiring access tokens at some point.
When it does, it must specify a resource parameter.
This parameter says to AAD which API you wish to call.
In the case of the "ApiService", you should use either its client id or Application ID URI (this is more common).
Depending on the type of your Web App, the access token is acquired a bit differently.
For "traditional" back-end apps, the Authorization Code Grant flow is usually used.
In this flow your back-end gets an authorization code after the user logs in, and your Web App can then exchange that code for the access token.
In the case of a front-end JavaScript app, you would use the Implicit Grant flow, which you have allowed (no need to enable it in the API by the way).
This one allows you to get access tokens directly from the authorization endpoint (/oauth2/authorize) without talking to the token endpoint as you usually have to.
You can actually get the access token right away after login in the fragment of the URL if you wish.
ADAL.JS makes this quite a lot easier for you if you are going in this route.
The reason you get the authentication error is because the access token is probably meant for Microsoft Graph API. You need to request an access token for your API.
An access token is always only valid for one API.