For the past 10+ days I've read an watched ALL the content I could find on understanding OAuth2 and OpenID Connect, only to find that many people disagree on the implementation, which really confuses me.
To my understanding, all the articles and examples I found assume you want access to eg. google calendar, profile info or emails if you eg. login with google, but I do NOT need to access other than my own API's - I only want to use Google, Facebook etc for logging in, and getting an id which I can link to my user in my own database - nothing more than that.
I'll try illustrate my use case and use that as an example.
A note on the diagram: the Authentication service could probably be built into the API Gateway - not that i matters for this example, since this is not about "where to do it", but "how to do it the best way" possible, for an architecture such as mine, where it's used for my own API's / Microservices, and not accessing Google, Facebook etc. external API's
If you can understand what I'm trying to illustrate with this diagram above, please tell me if I've misunderstood this.
The most basic requirements for this architecture you see here are:
Users can login with Google, Facebook, etc.
The same login will be used for all micro-services
OpenId user will have a linked account in the database
User access is defined in my own db, based on groups, roles and permissions
I do not intend to use external API's after the user is authenticated and logged in. No need for ever accessing a users calendar, email etc. so I really just need the authentication part and nothing else (proof of successful login). All user access is defined in my own database.
So a few fundamental questions comes to mind.
First of all, is OpenID Connect even the right tool for the job for authentication only (I'll have no use for authorization, since I will not need read/write access to google / facebook API's other than getting the ID from authenticating)?
People generally do not agree on whether to use the ID or Access token for accessing your own API's. As far as I understand the ID token is for the client (user-agent) only, and the access token is for eg. accessing google calendar, emails etc.... External API's of the OpenID Provider... but since I'll only be accessing my own API's, do I event need the access token or the ID token - what is the correct way to protect your own API's?
If the ID token is really just for the client, so it can show eg. currently logged in user, without going to the DB, I have 0 use for it, since I'll probably query the user from from the db and store it in redux for my react frontend app.
Dilemma: To store user details, groups, roles and permission inside JWT or not for API authorization?
By only storing the user identifier in the token, it means that I always allow authenticated users that has a valid token, to call endpoints BEFORE authorization and first then determine access based on the db query result and the permissions in my own database.
By storing more data about the user inside the JWT, it means that in some cases, I'd be able to do the authorization / access (group, role, permission) check before hitting the API - only possible with user info, groups, roles and permission stored inside a JWT issued upon login. In some cases it would not be possible due to eg. the CMS content access permissions being on a per-node level. But still it would mean a little better performance.
As you can see on the diagram I'm sending all API requests through the gateway, which will (in itself or with an authentication service) translate the opaque access token into some JWT with an identifier, so I can identify the user in the graph database - and then verify if the user has the required groups, roles and permissions - not from an external API, but from my own database like you see on the diagram.
This seems like a lot of work on every request, even if the services can share the JWT in case multiple services should need to cross call each other.
The advantage of always looking up the user, and his permissions in the db, is naturally that the moment the user access levels change, he is denied/granted access immediately and it will always be in sync. If I store the user details, groups, roles and permission inside a JWT and persist that in the client localstorage, I guess it could pose a security issue right, and it would be pretty hard to update the user info, groups, roles and permissions inside that JWT?
One big advantage of storing user access levels and info inside the JWT is of course that in many cases I'd be able to block the user from calling certain API's, instead of having to determine access after a db lookup.
So the whole token translation thing means increased security at the cost of performance, but is is generally recommended and worth it? Or is it safe enough to store user info and groups, roles, permissions inside the JWT?
If yes, do I store all that information from my own DB in the ID Token, Access token or a 3rd token - what token is sent to the API and determines if the user should be granted access to a given resource based on his permissions in the db? Do I really need an access token if I don't need to interact with the ID providers API? Or do I store and append all my groups, roles, permissions inside the ID token (that doesn't seem clean to me) issued by OpenID connect, and call the API and authorize my own API endpoints using that, even if some say you should never use the ID token to access an API? Or do I create a new JWT to store all the info fetched from my database, which is to be used for deciding if the user can access a given resource / API endpoint?
Please do not just link to general specs or general info, since I've already read it all - I just failed to understand how to apply all that info to my actual use case (the diagram above). Try to please be as concrete as possible.
Made another attempt to try and simply the flow:
The following answer does only apply for a OpenID Connect authentication flow with a 3rd party IDP (like Google). It does not apply for an architecture where you host your own IDP.
(There are some API gateways (e.g Tyk or Kong) which support OpenID Connect out of the box.)
You can use JWTs (ID token) to secure your APIs. However, this has one disadvantage. JWTs cannot be revoked easily.
I would not recommend this. Instead you should implement an OAuth2 authorization server which issues access tokens for your API. (In this case, you have two OAuth2 flows. One for authentication and one for authorization. The ID and access token from the IDP are used only for authentication.)
The following picture shows a setup where the API gateway and authentication/authorization server are two separate services. (As mentioned above, the authentication/authorization can also be done by the API gateway.)
The authentication flow (Authorization Code Grant) calls are marked blue. The authorization flow (Implicit Grant) calls are marked green.
1: Your web app is loaded from the app server.
2a: The user clicks on your login button, your web app builds the authorization URL and opens it. (See: Authorization Request)
2b: Because the user hasn't authenticated and has no valid session with your authorization server, the URL he wanted to access is stored and your authorization server responds with a redirect to its login page.
3: The login page is loaded from your authorization server.
4a: The user clicks on "Login with ...".
4b: Your authorization server builds the IDP authorization URL and responds with a redirect to it. (See: Authentication Request)
5a: The IDP authorization URL is opend.
5b: Because the user hasn't authenticated and has no valid session with the IDP, the URL he wanted to access is stored and the IDP responds with a redirect to its login page.
6: The login page is loaded from the IDP.
7a: The user fills in his credentials and clicks on the login button.
7b: The IDP checks the credentials, creates a new session and responds with a redirect to the stored URL.
8a: The IDP authorization URL is opend again.
(The approval steps are ignored here for simplicity.)
8b: The IDP creates an authorization and responds with a redirect to the callback URL of your authorization server. (See: Authentication Response)
9a: The callback URL is opened.
9b: Your authorization server extracts the authorization code from the callback URL.
10a: Your authorization server calls the IDP's token endpoint, gets an ID and access token and validates the data in the ID token. (See: Token Request)
(10b: Your authorization server calls the IDP's user info endpoint if some needed claims aren't available in the ID token.)
11a/b: Your authorization server queries/creates the user in your service/DB, creates a new session and responds with a redirect to the stored URL.
12a: The authorization URL is opend again.
(The approval steps are ignored here for simplicity.)
12b/+13a/b: Your authorization server creates/gets the authorization (creates access token) and responds with a redirect to the callback URL of your web app. (See: Access Token Response)
14a: The callback URL is opened.
14b: Your web app extracts the access token from the callback URL.
15: Your web app makes an API call.
16/17/18: The API gateway checks the access token, exchanges the access token with an JWT (which contains user infos, ...) and forwards the call.
A setup where the authorization server calls the API gateway is also possible. In this case, after the authorization is done, the authorization server passes the access token and JWT to the API gateway. Here, however, everytime the user infos change the authorization server has to "inform" the API gateway.
This is a very long question. But I believe most can be summarised by answering below,
To my understanding, all the articles and examples I found assume you want access to eg. google calendar, profile info or emails if you eg. login with google,
You do not necessarily use Access token (ID token in some occasions) to access the services offered by token issuer.You can consume tokens by your own APIs. What these Identity Providers (synonym to Authorization server, or IDP in shorthand) is to hold identities of end users. For example, typical internet have a Facebook account. With OAuth and OpenID Connect, the same user get the ability to consume your API or any OAuth/OIDC accepted service. This reduce user profile creation for end users.
In corporate domain, OAuth and OIDC serves the same purpose. Having a single Azure AD account lets you to consume MS Word as well as Azure AD's OIDC will issue tokens which can be used to Authorise against an in-house API or an third party ERP product (used in organization) which support OIDC based authentication. Hope it's clear now
A note on the diagram is that the Authentication service could probably be built into the API Gateway - not sure if that would be better?
If you are planning to implement an API gateway, think twice. If things are small scale and if you think you can maintain it, then go ahead. But consider about API managers which could provide most of your required functionalities. I welcome you to read this article about WSO2 API manger and understand its capabilities (No I'm not working for them).
For example, that API manager has built in authentication handling mechanism for OAuth and OIDC. It can handle API authentication with simple set of configurations. With such solution you get rid of the requirement of implement everything.
What if you can't use an API manager and has to do it yourself
OpenID Connect is for authentication. Your application can validate the id token and authenticate end user. To access APIs through API Gateway, I think you should utilise Access token.
To validate the access token, you can use introspection endpoint of the identity provider. And to get user information, you can use user-info endpoint.
Once access token is validated, API gateway could create a session for a limited time (ideally to be less or equal to access token lifetime). Consequent requests should come with this session to accept by API gateway. Alternatively, you can still use validated access token. Since you validated it at the first call, you may cache for a certain time period thus avoiding round trips to validations.
To validate user details, permission and other grants, well you must wither bind user to a session or else associate user to access token from API gateway at token validation. I'm also not super clear about this as I have no idea on how your DB logic works.
First Appreciate your patience in writing a very valuable question in this forum
we too have same situation and problem
I want to go through ,as images are blocked in our company in detail
Was trying to draw paralles to similar one quoted in the book
Advance API In Practise - Prabath Siriwerdena [ page 269]Federating access to API's Chapter. Definitely worth reading of his works
API GW should invoke Token Exchange OAUTH2.0 Profile to IDP [ provided the IDP should support TOken Exchange profile for OAUTH 2.0
The Absence of API Gateway , will result in quite bespoke development
for Access Control for each API Check
you land up in having this check at each of the api or microservice [ either as library which does work for you as a reusable code]
definitely will become a choking point.]
Goal
Fetch a company's updates save them locally in a background task
Problem
This should be done as a backend service without any real user interaction. We could provide a user account to use, but the authentication is a problem: There is literally no one to answer the OAuth redirect and there is no public redirect URL to configure, since it's a background service.
Is there any way to access the API without having a redirect URL or a real user?
You can get an initial access token in a regular front end flow, for you as the app developer i.e yourself as the LinkedIn user. Once you've got that, you can store it in the backend and use it for 60 days to get access to the LinkedIn APIs.
After 60 days you need to refresh the token as documented in:
https://developer.linkedin.com/documents/handling-errors-invalid-tokens
Unfortunately LinkedIn does not (yet) support an autonomous refresh flow where your app can get a new access token by presenting a refresh token on a backchannel. So the developer will have to refresh the access token by a manual login every 2 months.
Well, it is still all HTTP and HTML, so in fact there is no real reason to show the OAuth dialog to a user, as long you can strip out the necessary parts in the HTML authentication dialog and send a valid response back to the server, using the username and password from the user (which you can obtain from him, or save it yourself in a config file if it is you).
Note that there might be a legal issue if LinkedIn demands you to actually show the dialog, beside that, there is no technical need.
I am in the process of designing an app that is supposed to let you login using either a username/password combination or facebook login. We have a custom OAuth server that uses user credentials to authenticate users. Now, the question is how to add facebook into this.
As I see it now, when the user wants to login with facebook, the client does all the work and gets the access token in the end. But how do we let our server know that this access token is a good one (and corresponds to a user in the database)? To me it seems like our OAuth server should be able to handle this as well, and I'm just missing the how.
OAuth supports different scenarios (flows). Client-does-all-the-work is so called "implicit" flow.
In your case it would be better to use authorization-code flow and extend your OAuth server. You put a "Facebook" button on your login page and instruct Facebook to redirect to a new special page on your OAuth server. Delivered authorization code then can be exchanged to the access token inside of your OAuth server and the server may issue its own session and tokens based on this.
Let's say, i want to develop a rest api implementation and use OAuth 2.0 with authorization_code grant. I will have apps, users, access_tokens etc. I just couldn't imagine only one scenario. When a user permits an app to use it, my auth server will redirects him to app site with auth code and then the app will post it with its client_id to fetch access_token. So, how can i link this access_code to the user? At last, the app will want to access to some resource about THE USER and will post the access_code which my auth server created to access it. Or just the app should store to link between access_code and the user id(but how can it determine the user, it is an another question).
The Authorization server have to provide a service to give the resource server user information but using access_token so the resource server can get user Id and other information to use it, example of it is using login with FB or google, it is providing user information to the 3rd party want to authenticate this user.
How do I secure my API when I want an app to be able to retrieve app-specific information without a user logged in and when I have an OAuth provider for another section of my API? Can I use the client app's OAuth credentials to hit the API without a user logged in?
I have create an OAuth provider and client using doorkeeper following railscasts 353. I can successfully authenticate a user to my provider app and make requests on behalf of the user to my provider API.
However, a portion of the API is user independent, meaning that the information returned from the API is not specific for a user and therefore a user should not have to be logged in. For example, assume an ecommerce site and items and prices are stored on the provider for multiple clients. I want a client app to be able to securely retrieve the items/prices associated the retrieving app without a user having to be logged in. So if you went to example.com the items would be displayed even if a user is logged in via OAuth.
I have only be able to retrieve this information via OAuth when a user has logged in through OAuth (creating an access_token). Is there a way to use OAuth without having a user present (I've been trying to read about 2-legged OAuth and if that is an appropriate solution)? Or do I need to use Api keys (or Http Basic Auth) for the application to retrieve the application specific data?
If OAuth is not the right solution because I do not have a user present, could/should I use HTTP Basic Auth over SSL and use the client site's OAuth secret key as the API key for the basic auth username?
If you need to authenticate your client apps in you API (without requiring a user specifically) use the Client Credentials flow