Google Cloud Endpoints Security (OAuth2) and custom User schema - java

I'm reading the Google Cloud Endpoints docs related to OAuth2 Security.
I assume this kind of security is against Google accounts.
Is there any support to have a custom User schema to authenticate against?
What I would like is to have client JS application which uses Google Cloud Endpoints but authenticate against local storage (App Engine) of users.
Is Google Clound Endpoints suitable for this or do I need to write my own Security mechanism?

My understanding of OAuth is:
An end point is implemented by a provider, so when an application such as yourself, authenticates a user such as myself, it returns a result.
Now the problem is if google's end points can return custom schema.
What you could do is, implement the functions, and change your DNS (/etc/conf) so that google's endpoints hit your localhost. In principal this will work, however in practice I am not sure I would do this myself, but perhaps you have your reasons.
So with AppEngine, I imagine there might be a class which overrides/implements this stuff. With the DNS rewrite trick, you should be able to get it to work.
If you do, please write about it, so it can help others.

The OAuth for Cloud Endpoints is Google accounts only. You would have to write your own.
Honestly, just use Google Accounts, user can even sign up for Google accounts with their own email address. In the future they will probably support Open ID with Endpoints as well.

Related

Direct Access Grant with KeyCloak using external Identity Provider (IDP)

I would like to authenticate against KeyCloak using "Direct Access Grant": https://www.keycloak.org/docs/latest/server_admin/index.html#resource-owner-password-credentials-grant-direct-access-grants
I works like a charm when keycloak manages users and passwords on its own.
But, my scenario is different:
I would like keycloak to act a Broker to some external IDP. KeyCloak has identity brokering feature - but in only works in "Authorization Code flow" - redirecting user to external IDP login form.
I have mobile app and would like ot use "direct access grant" - so that app comunicates with keycloak to authenticate user - and keycloak, as a broker, authenticates this user (using openid-connect) in external IDP
How to achieve such scenario ? I know that it is not possible out of the box - but maybe somebody could advice how write an extension to keycloak do make this scenario possible ?
Whatever it is you are trying to achieve this way, it goes directly against what OAuth and OpenID Connect were designed for. The whole idea of using access tokens is to allow some relying party (such as a mobile app) to interact with a service on behalf of the user without ever getting to see the user's credentials (like a password).
Think of it like this. Let's say you have some app on your mobile phone. It can make use of certain services by Google. In order to do so it offers you to log in with Google and grant the app access. Now, would you want to do so by putting your Google email and password directly into the app? Of course not. That could give it complete control over your Google account, other apps and sites using your Google identity, possibly services that allow you to pay through your Google wallet... It would be insane to simply hand some phone app your Google login.
So instead with OAuth2 or OpenID Connect you can use the authorization code flow or implicit flow to have the user redirected to the identity provider (Google in our example) where they will complete their login process, and then the identity provider redirects back to the app or a site with an authorization code that can be exchanged for tokens or, for the implicit flow, the tokens themselves.
Now, when it's your own app and your own identity provider (like Keycloak) which are under your control it doesn't really matter. You can use a direct grant to simply have the user input their username and password into the app because you know it's not trying to steal user credentials to maliciously use your service. They're both under your control. In that case OAuth or OIDC are a bit overkill, but you could have separate clients for direct grants (your own app) and authorization code flows (third-party apps using your service). When you want to use Keycloak identity brokering, however, an external identity provider like Google or Facebook is not going to offer a direct grant and invite apps to steal their user's credentials. So you won't be able to interact with them this way.
Depending on what you're trying to achieve you may find some use in the token exchange process. If however the idea is that you want your user to log in with their external identity provider credentials, in your app, without a redirect... Don't.
This is a real use case, unfortunately Keycloak doesn't have a direct way of solving this issue. AWS's "IAM Roles for Service Account" feature works based on token exchange with direct access grant using external IDP. I found this discussion on how to workaround this lack of support in Keycloak but not sure if it solves all the usecases - https://lists.jboss.org/pipermail/keycloak-user/2017-January/009272.html
Do you stick with Direct Access Grant as a method of user authentication in your mobile app? In my opinion, you need to use Authorization Code Flow when the IDP is a third party service as it won't provide an API to authenticate users, and even with your own (first party) IDP, it'd be better to use Authorization Code Flow as stated in OAuth 2.0 Security Best Current Practice section 2.4.
To implement Authorization Code Flow in mobile apps, you will need to use in-app browser tab to show login screen provided by the IDP. Please refer to RFC 8252: OAuth 2.0 for Mobile and Native Apps for details.

Is possible to create a role based application with OAuth2?

What I'm trying to do is to create an application with Angular frontend and Spring Boot backend with OAuth2 authentication.
The issue is that I don't know how to get on the frontend the ROLES user has so that I'll be able, for instance, to show something role-based on the page. Yes, there are scopes that OAuth provides in the response but the problem is that these scopes are for the CLIENT but not for the specific USER itself. And that CLIENT is my frontend side (correct me if I'm wrong) which basically means that every user operating my application(client) going to have the same scopes(roles). Moreover, I can specify roles on the backend with the help of Spring and UserDetailsService and then use those roles with #PreAuthorize, etc. But not on the frontend side.
Just as an example, if I simply used single JWT then with a token itself I'd return both the username and roles to frontend. And then I could store that data and use it on the frontend side according to my needs.
So what I'm asking is if it's actually possible and if this is correct to do so?
And how can I possibly implement such behavior?
OAuth doesn't solve this problem and it is best solved via claims in your API. OAuth should deal with authentication only. My below post may help you to think about the best separation: https://authguidance.com/2017/10/03/api-tokens-claims/
In a nutshell you will have to look up user rights such as roles after the OAuth processing completes.
There is a great video from Spring developer on YouTube about OAuth2/OpenID Connect. It shows how to implement the resource server using the newest Spring Security 5 solution.
Probably the easiest and the best way to achieve this is to use an OpenID Connect server which will provide all user management stuff. On the market there are many solutions. Auth0 and Okta are Identity Clouds which provides their services for small amount of money. On the other hand you have Keycloak, which is a server which you can install in Docker or even on bare metal - it's free and open-source.

How to access Google API's from Android, using "Public API access", not user authentication

Background
I believe the recommended way to access Google services from Android is to use the Google APIs Client Library for Java (for some services play services is recommeneded too).
If you want to access your user's account, you use oauth2 to authenticate the user, but things seem less clear if you want to access your own services (eg. I want to access Google Cloud Storage belonging to my app engine project).
The problem with service accounts
What I see a lot of here is using service accounts, and I've used them server-side and found them to be a comparatively simple solution, but this requires you to deploy your private key so I don't think this could be right for public Android apps.
The solution: Public API access
If you go to the 'credentials' page of the cloud console:
https://console.developers.google.com/project/[your_project]/apiui/credential
it seems pretty clear that they expect you to use a 'public API access key' for the situation I'm describing. It appears that this is not OAUTH based.
I assume that I will still use the type 'GoogleCredential' for this, but in the documentation for the credential builder I don't see how to do this. The set client functions appear to relate to the oauth2 access (which uses client ID/secret).
The Question
How do I use the 'public API access' key to access Google services from an Android app.
Or, if I'm wrong about service accounts - and they really are the recommended solution, then please show me some evidence of this because it certainly apppears to me that they are not the right solution for publicly distributed apps.
The good news is that it's very much easier. You can either use a Service Account (ie. a brand new account dedicated to your app) or a regular account.
For a service account you embed the key in your app, for a regular account you embed a refresh token in your app. In both cases, be aware of the security risk and use the minimal scope necessary.
You can get a refresh token without writing any code by following the steps in How do I authorise an app (web or installed) without user intervention? (canonical ?)

Custom android authenticator using Google App Engine

I would like to write a custom authenticator for Android. I found this nice tutorial to do it, but instead of using Parse as authentication server, I want to use Google App Engine:
http://udinic.wordpress.com/2013/04/24/write-your-own-android-authenticator/
The problem is that I couldn’t find the way to do it. Do you know if that is possible?
All I can find is how to implement authentication using a Google account, but I’d rather prefer to allow users to use any email account.
Thanks.
You have plenty of choices, the first ones that come to mind:
You can use 3rd party OAuth providers which not all email providers are.
Implemment and use your own Authenticator.
(Recommended) Since you are not accessing user data through OAuth just implement a standard user/password authentication method using endpoints and secure the API using your android's app SHA fingersprint, as explained here

Verifying Twitter OAuth on BlackBerry

Hey all, i want to integrate my Blackberry App with Twitter, and found that the way to do it is with OAuth. The problem I have is that i would like to do the verification of this from my server as to put less strain on the device, but I have no idea how to get the OAuth PIN from the server to be displayed on the device so the user can enter it, any ideas as to how i can do this? or an alternative ?
You can't. OAuth was designed such that only the service provider can provide authentication (so that the developers don't have to store their client passwords on their database servers and if the client changes their passwords, then it would have to be managed also on the developers side too). There is only one source of authentication and that's from the service provider (Twitter, in this case). Sharing of passwords is therefore eliminated.
OAuth doesn't work on PINs but rather using Request/Access Token. Follow the Beginners' Guide to OAuth and Twitter Developer's Auth Page to see how you can incorporate OAuth to Twitter. Just to give you an heads up, you will have to register your application to Twitter.
Update For Mobile and Desktop applications, rather go through Twitter's xAuth. Here's a documentation on how to register and use your application to use xAuth.
Twitter OAuth FAQ.

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