AppEngine Cloud Endpoints and custom Users service - google-app-engine

Is it possible to use a custom Users service (a service that implements UsersService interface) with Google AppEngine endpoints?
Let's take the example from Google AppEngine website
#ApiMethod(name = "greetings.authed", path = "greeting/authed")
public HelloGreeting authedGreeting(User user) {
HelloGreeting response = new HelloGreeting("hello " + user.getEmail());
return response;
}
When a request is made to the application and this endpoint is hit it somehow contacts the Users service and gets the information about authenticated user (because the OAuth token is available in the request).
I'd like to somehow use my own service which would implement UsersService interface and provide me with a user object.

Related

ASP.NET 6 WebAPI Authentication with SSO

I have an ASP.NET 6.0 Web API project. I would like to add authentication and authorization to it, but it must use SSO via Azure.
We already have a SPA application that does this, it uses the Angular MSAL library to redirect the user to an SSO Login page, then returns to the SPA with an access token. The access token is then added to the header of each request to the Web API, which uses it to enforce authentication.
Now we want to share our web API with other teams within our organization, and we would like to have that login process just be another API call, rather than a web page.
Conceptually, a client would hit the /login endpoint of our API, passing in a userID and password. The web API would then get an access token from Azure, then return it as the payload of the login request. It's then up to the client to add that token to subsequent request headers.
I have done this with regular ASP.NET Identity, where all of the user and role data is stored in a SQL database, but since our organization uses SSO via Azure Active Directory, we would rather use that.
I have researched this topic online, and so far all of the examples I have seen use a separate SPA, just like we already have. But as this is a web api, not a front-end, we need to have an API method that does this instead.
Is this even possible? I know Microsoft would rather not have user credentials flow through our own web server, where a dishonest programmer might store them for later misuse. I understand that. But I'm not sure there's a way around this.
Thanks.
I believe you are looking for the Resource Owner Password (ROP) flow. You can use IdentityModel.OidcClient to implement it.
Sample code:
public class Program
{
static async Task Main()
{
// call this in your /login endpoint and return the access token to the client
var response = await RequestTokenAsync("bob", "bob");
if (!response.IsError)
{
var accessToken = response.AccessToken;
Console.WriteLine(accessToken);
}
}
static async Task<TokenResponse> RequestTokenAsync(string userName, string password)
{
var client = new HttpClient();
var disco = await client.GetDiscoveryDocumentAsync(Constants.Authority);
if (disco.IsError) throw new Exception(disco.Error);
var response = await client.RequestPasswordTokenAsync(new PasswordTokenRequest
{
Address = disco.TokenEndpoint,
ClientId = "roclient",
ClientSecret = "secret",
UserName = userName,
Password = password,
Scope = "resource1.scope1 resource2.scope1",
Parameters =
{
{ "acr_values", "tenant:custom_account_store1 foo bar quux" }
}
});
if (response.IsError) throw new Exception(response.Error);
return response;
}
}
Sample taken from IdentityServer4 repository where you can find more ROP flow client examples.
I would recommend that you don't go with this implementation and instead have all clients obtain their access tokens directly from Azure AD like you did with your Angular SPA.

Azure Authentication from client app to another API

I'm trying to get azure AD authentication working between a Blazor WASM app, and another API that I have running locally but on a different port. I need both applications to use the Azure login, but I only want the user to have to log in once on the Blazor app which should then pass those credentials through to the API.
I've set up app registrations for both apps in the portal, created the redirect url, exposed the API with a scope and I can successfully log into the blazor app and see my name using #context.User.Identity.Name.
When it then tries to call the API though, I get a 401 error back and it doesn't hit any breakpoints in the API (presumably because there is no authentication being passed across in the http request).
My code in the Blazor app sets up a http client with the base address set to the API:
public static async Task Main(string[] args)
{
var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");
builder.Services.AddHttpClient("APIClient", client => client.BaseAddress = new Uri("https://localhost:11001"))
.AddHttpMessageHandler<BaseAddressAuthorizationMessageHandler>();
builder.Services.AddScoped(sp => sp.GetRequiredService<IHttpClientFactory>().CreateClient("APIClient"));
builder.Services.AddMsalAuthentication<RemoteAuthenticationState, CustomUserAccount>(options =>
{
builder.Configuration.Bind("AzureAd", options.ProviderOptions.Authentication);
options.ProviderOptions.DefaultAccessTokenScopes.Add("api://d3152e51-9f5e-4ff7-85f2-8df5df5e2b2e/MyAPI");
//options.UserOptions.RoleClaim = "appRole";
});
await builder.Build().RunAsync();
}
In my API, I just have the Authorise attribute set on the class, and eventually will need roles in there too:
[Authorize]
[Route("api/[controller]")]
[ApiController]
public class CarController
Then, in my Blazor component, I then inject the http factory and try to make a request:
#inject IHttpClientFactory _factory
...
private async Task RetrieveCars()
{
var httpClient = _factory.CreateClient("APIClient");
HttpResponseMessage response = await httpClient.GetAsync("https://localhost:11001/api/cars");
var resp = await response.Content.ReadAsStringAsync();
cars = JsonSerializer.Deserialize<List<Car>>(resp);
}
but this returns the 401 error. I've also tried a few different variations like just injecting a http client (#inject HttpClient Http) but nothing seems to be adding my authorisation into the API calls. The options.UserOptions.RoleClaim is also commented out in the AddMsalAuthentication section as I wasn't sure if it was needed, but it doesn't work with or without it in there.
Can anyone explain what I'm doing wrong and what code I should be using?
Common causes.
Most cases ,we tend to forget to grant consent after giving API
permissions in the app registration portal,after exposing the api
which may lead to unauthorized error.
Other thing is when Audience doesn’t match the “aud” claim when we
track the token in jwt.io .Make sure ,Audience=clientId is configured
in the code in authentication scheme or Token validation parameters
by giving ValidAudiences.And also try with and without api:// prefix
in client id parameter.
Sometimes aud claim doesn’t match as we mistakenly send ID token
instead of Access tokens as access tokens are meant to call APIs .So
make sure you check mark both ID Token and access token in portal
while app registration.
While Enabling the authentication by injecting the [Authorize]
attribute to the Razor pages.Also add reference
Microsoft.AspNetCore.Authorization as(#using
Microsoft.AspNetCore.Authorization)
Please see the note in MS docs and some common-errors
If above are not the cases, please provide with additional error details and startup configurations or any link that you are following to investigate further.

Blazor WASM calling Azure AAD secured Functions API

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);
...
}

How can you get the Google+ Profile of the current user when using Google Cloud Endpoint's (Java) built in authentication?

My Setup
Backend: Google App Engine (Java) w/ Google Cloud Endpoints using Endpoint's built in authentication
Frontend: AngularJS web app
Problem
I need to get the Google+ profile for my users. The keyword "me" can generally be used to get the current user's Google+ profile, however since all the authentication, in Google Cloud Endpoints, is done under the hood, I don't see anyway to get credentials, nor a token, for the current user. All you get it the com.google.appengine.api.users.User object.
Is there any way to get user credentials, or the access token, when using Google Cloud Endpoint's built in authentication?
Note: Google+ profile ID is different form Google account ID.
Possible Solution
I could just use the Google+ JS client with the keyword "me" and have the user send their Google+ ID and then subsequently store it and tie it to their Google Account ID, but this would be incredible insecure as the user could hack their way to sending the ID of any Google+ account.
It is possible to get the user access token when using Google Cloud Endpoint's built in authentication.
Add the parameter HttpServletRequest request to your Google Cloud endpoint as shown below. This will allow you to get the raw request.
You will then need to retreive the header called Authentication. This will get a Bearer access token that will allow you to build credentials to impersonate the authenticated user.
Next you will use that Bearer access token to build a com.google.api.client.googleapis.auth.oauth2.GoogleCredential object. You will need this to build the Plus service.
Use the Plus builder to build a Plus service object with the credential you just created.
Sample Code
#ApiMethod(path = "myPath")
public void myEndpoint(HttpServletRequest request, ParmOne paramOne, ...) throws OAuthRequestException {
if (user == null) {
throw new OAuthRequestException("Authentication error!");
}
GoogleCredential credentialAsUser = new GoogleCredential().setAccessToken(request.getHeader("Authorization").substring(7)); // Start string at index position 7 to remove prefix "Bearer" from token.
Plus plus = new Plus.Builder(new UrlFetchTransport(), new JacksonFactory(), credentialAsUser).setApplicationName("my-app").build();
Person profile = plus.people().get("me").execute();
}
Documentation
The Java docs for the Google Plus client can be found here.
The Java docs for instructions on creating Google credentials can be found here.
Additional Answer for Android Clients
Problem
In addition to the Marc's answer it is important that the GoogleCredentials-Object needs an access_token in the request-header.
If you call the endpoint with your apiExplorer or a javascript endpoint, this token is already served in the Authorization-header. But if you follow the docs for an android client your requests header contains an id_token, so GoogleCredentials.setAccessToken does not work.
Solution
To change the type of authorization to an access_token simply create your GoogleAccountCredential-Object in Android with usingOAuth2 instead of usingAudience.
Example
Replace this code in your Android App
credential = GoogleAccountCredential.usingAudience(this,
"server:client_id:1-web-app.apps.googleusercontent.com");
with this
credential = GoogleAccountCredential.usingOAuth2(this,
Collections.singleton(Scopes.PLUS_LOGIN));
and send it to your Api, as it is explained by the documentation
Helloworld.Builder helloWorld = new Helloworld.Builder(AppConstants.HTTP_TRANSPORT,
AppConstants.JSON_FACTORY,credential);

GAE Open-ID Federated Authentication using Java Script End Point

I want to use GAE Open-ID Federated Authentication using Java Script (without Java Servlet) End Point.
Is it supported via Java Script (without Java Servlet) End Point?
If yes how could I use Open-ID Federated Authentication with Java Script end point API call?
I had tried User in endpoint API
#ApiMethod(
name = "signMe.signGoogleId",
httpMethod = "POST",
scopes = { "https://www.googleapis.com/auth/userinfo.profile" , "https://www.googleapis.com/auth/userinfo.email" }
)
public SignIn signInOpenId(User user)throws
OAuthRequestException, IOException
{
User is null always even after logging with Google\Yahoo User.
I had tried HttpServletRequest req in endpoint API.
#ApiMethod(
name = "SignMe.signOpenId",
httpMethod = HttpMethod.GET,
scopes = { "https://www.googleapis.com/auth/userinfo.profile" , "https://www.googleapis.com/auth/userinfo.email" }
)
public SignIn signInOpenId(HttpServletRequest req)
throws IOException
{
UserService userService = UserServiceFactory.getUserService();
User newUser = userService.getCurrentUser();
newUser is null always even after logging with Google\Yahoo User.
Thanks,
Deepak
You could always dump the cloud endpoints way of doing it and go with general API authentication.
https://developers.google.com/appengine/articles/openid#fa
As would be done for non Cloud Endpoints applications. The down side is you wouldn't get any client authorization abilities, so any client code hit your API.
Google Cloud Endpoints OAuth does not seem to support Open ID at this time.

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