Omniauth Strategy Outside Devise - ruby

I've setup devise + omniauth for Google sign in. It works great on the web. I'm now looking at integrating the oauth sign in to iOS / Android clients.
I've been following https://developers.google.com/identity/sign-in/ios/backend-auth and found that the library I'm using for oauth does these things (https://github.com/zquestz/omniauth-google-oauth2/blob/master/lib/omniauth/strategies/google_oauth2.rb).
What I'm not clear about is if I can use a omniauth strategy outside the regular web workflow (i.e. from rails console) to build a pseudo request.env["omniauth.auth"]. Is something like that possible? Per the documentation https://developers.google.com/identity/sign-in/ios/backend-auth#using-a-google-api-client-library I'd like to do the equivalent in Ruby (and am unclear if I can use Devise directly to do this).

Simulating requests in the console is pretty easy. You can easily make requests to the app variable the console provides:
app.get('/') # => 200
app.response # => #<ActionDispatch::TestResponse:0x007fc73e4db220>
As for handling authentication, standard rails applications use cookie/session-based authentication strategies on the web. After you authenticate the first time, some information gets stored in session (often as a cookie) that you and the server will pass back and forth with each request.
Since mobile clients don't rely on cookies, we need a different authentication strategy: token-based authentication.
Here a high-level implementation that would work with Omniauth:
User Requests Access through Omniauth proivder by making requests to the Omniauth endpoint
Application processes the credentials
Application provides a signed token to the client
Client stores that token and sends it along with every request
Server verifies token and responds with data
For handling mobile requests, you'll need to be careful to follow the fine print for the provider's Omniauth gem.
Token authentication used to be baked into Devise, but it was removed. Thankfully, there are a few gems that add token auth to Devise:
simple_token_authentication
devise_token_auth

Related

Securing web app and api using OpenID Connect

I don't want to roll my own security anymore and am looking at using OpenID Connect with my c# API and AngularJS app. I can get all that to work just fine. However, my brain cannot seem to understand how to secure my API correctly for both use cases:
Use Case 1: AngularJS SPA
My AngularJS app connects to my API and sends a bearer token identifying the user and includes user claims. This one is easy and there is tons of documentation on it.
Use Case 2: API to API
Some customers want to access my API directly instead of going through my AngularJS app. In this case, I thought I could use a Client ID/Secret for toen-based authentication which is great except then I know nothing about the user that's using the client id/secret. There could be 10 users using the same custom API that is calling my API. How do I get user info via the API call? I've seen others use API keys that they then lookup the user and create a JWT but I thought there might be an easier way. Any ideas?
The whole point of API to API authentication is that there is no user context. Or well, the user in that case is the machine trying to access your API. You would then need to design your authorization logic around that and implement scope based permissions. Alternatively, your options are to use api keys as you mentioned or if you want OAuth protocol with user context in the api to api scenario - then ResourceOwnerCredentials flow is an option.
API to API communcation
You can use Client Credentials Grant defined through OAuth 2.0. This won't require you to have end user credentials. Now this won't be OpenID Connect. OpenID Connect require the involvement of an end user and bound to authentication. OAuth 2.0 on the other hand is about authorization, checking whether the entity can access the resource.
With Client Credential Grant, your identity server will issue tokens for a specific client. So one of your API becomes the client (resource consumer). From request handling API endpoint, you can accept valid tokens and respond back with resource.
If you require fine grained access control from request handling API, you will require to use token introspection to identify to whom this token was issued. In this case, it will be identification of specific client identity and execute a logic on top of it. You can check the token introspection response to identify such details.
Alternatively, access tokens can be come in form of a JWT. If this is the case, they can be considered as self contained tokens so validation is straightforward.

Autorization Code Flow with REST API "backend" on a different domain

We are using OIDC and IdentityServer in an enterprise deployment where at the moment we control everything (OP, clients, resources, users).
We have an SPA client that connects to its "own" API and will go through it for everything it requires to do. They are however being served from two different domains. (Let's say the application runs on "my.apps/app" and the API in "my.apis/api").
In our current setup, we use Implicit Flow to have the user authenticated in the SPA and then call the API and verify the token within it. This works very well.
We treat our API as a "resource" even though we don't need to and we don't require the user to give consent.
As mentioned, the SPA needs to go through the API for everything it does and this also includes augmenting user properties upon authentication, so the client doesn't even really let users work with it without going through the API.
Given that scenario, our thinking was that we could even be using Authorization Code flow for our OIDC authentication (treating the API as a backend) and get the security "benefit" of the browser never having access to the tokens.
However, due tue the applications being hosted separately we think this would require us to either:
Initiate the authentication request in the SPA, get the Authorization Code in the fragment but pass it later to the API which will in turn request the tokens and have them live in a cookie or something along those lines.
Initiate the authentication request in the SPA but use redirect_uri to the API domain, thus giving the Authorization Code to it which will request the tokens, have them live in a cookie and then redirect to the SPA again.
Basically we want to know if this is a setup that you think would work, what are the security concerns if any, and if it would be recommended for us to go ahead with this or to keep using Implicit Flow instead (specially from a security standpoint).

Require authentication or certificate to view Heroku app

I have an api deployed to Heroku. It is currently open for everyone to see. I only want known android phones to be able to modify and access the api.
I don't want the user to have to login every time they use the app.
Can I add some sort of certificate to the phone to verify that it is credible?
Is OAuth the best approach for this?
Is there a better way to do this so the user doesn't have to login every time?
This is a fairly broad question (and hence there are several approaches). Without knowing the language/framework you are using it's also hard to give specific advice, but:
Your server can issue a cookie or token that the client can store locally for a duration. These tokens should include a timestamp and be authenticated (use a library that does HMAC authentication) to prevent clients from modifying tokens.
Clients should present this token or cookie on each request to your server via a HTTP header or the standard Cookie header.
You will need a login system to support the initial issue of the token/cookie.
Clients could also OAuth against your server (complex) or against an external service (GitHub/Facebook/Google/Twitter), but you will still need a way to track that state on the client (hence a token/cookie).
Cookie support should be included with the standard Android HTTP client, and most server side frameworks have support (or a library for) authenticated cookies.

Angular CSRF token + ruby api

I'm currently running into a lot of issues with the CSRF token.
Our current setup is a Ruby API and an Angular front-end, both live on a different domain.
The Ruby back-end solely serves as an API for the front-end.
I've spend a lot of time researching this problem, but I can't find a proper solution.
So far the solutions I've found are:
Generate the token and insert it into the DOM (Different domains, so can't do that)
Let the API return the CSRF token on a GET request (Doesn't seem to work, and it's not a good solution since I don't want to make an extra request just to get the token)
So I'm rather stuck here and not sure how to continue.
Is the current implementation just not working? How do other people create an API with oauth without running into this issue?
Not sure if this will help but here is a sample of a simple todo api in ruby with angular as frontend, and i am using token for authentication generated after the user fills username and password.
https://github.com/sirfilip/todoapi/blob/master/app.rb (the api written in sinatra and sequel)
https://github.com/sirfilip/todoapiclient/blob/master/public/js/angular-todoapi-plugin.js (angular client api service that is used for communication with the api)
TL;DR: Secure your rails API with the doorkeeper gem.
This SO post seems to be the accepted answer when your api and client exist on the same domain.
In the post they outline the angularJS docs http://docs.angularjs.org/api/ng.$http :
Since only JavaScript that runs on your domain could read the cookie,
your server can be assured that the XHR came from JavaScript running
on your domain.
To take advantage of this (CSRF Protection), your server needs to set
a token in a JavaScript readable session cookie called XSRF-TOKEN on
first HTTP GET request. On subsequent non-GET requests the server can
verify that the cookie matches X-XSRF-TOKEN HTTP header
It seems that the security of storing and transferring the XSRF-TOKEN session cookie in this way hinges on having your api and your front-end be in the same domain. Since this is not the case, you may have to implement another form of authorization for any given client session, like OAUTH. I'd recommend taking a look at the doorkeeper gem. The gem will give you the ability to interact with your api as if you were any other client.

Authentication for Sinatra REST API app

I'm building an API with Sinatra (using Angular for the client side and want others to have access to API) and have it also be an OAuth provider. I am wondering what the best route to take (work off existing gems or roll own solution off Warden or something).
Have used devise and doorkeeper for authentication and oauth before with Rails, wondering what best solution for Sinatra is.
Ideally I don't want the views or be able to extend/mod the actions of an existing solution, as I'm interacting with it purely as an API.
I just recently did the same thing using the following answer from S/O
What is a very simple authentication scheme for Sinatra/Rack
It implies a user model, but instead of using that, I just set a user and admin password in my config file. Then I had a login form that just took a password. When the user enters that password, I checked it against the one in settings and set the session['user'] to :admin or :user according to whichever it matched (or nil if none). Then on each of my routes, I called auth: :user or auth: :admin accordingly.
APIs normally accept your login request and send you an authentication token which you need to pass back in each call. This is very similar to cookie based sessions where your browser automatically passes back the cookie which is acquired on initial website visit.
From what I've seen in Sinatra's docs, you could make a session-based authentication system like this:
enable :session
disable :show_exceptions
use Rack::Session::Pool,
key: 'session_id'
post '/login' do
user = User.login_success(params)
halt 401 if user.nil?
session[:user] = user
200
end
get '/fun' do
user = session[:user]
halt 401 if user.nil?
halt 403 if !user.has_permission_for '/fun'
"fun was had"
end
Now all you need to do in your client is to pass back the cookie token returned in response to initial visit when requesting an API function. This can be done with any web client library that supports cookie stores (such as libcurl) or by inserting the session cookie into the request header manually. Rack::Minitest functionality also supports cookies, so you can test your API with minitest.
See Sinatra API Authentication.
Quick summary:
Sinatra has no built-in auth.
It's best to build auth yourself (see the link).
There are gems available, but you probably won't need them for something as simple as an API.

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