Token Authenticatable module in Devise - ruby-on-rails-3

I'm starting using Devise in my Rails app, but the Token Authenticatable: signs in a user based on an authentication token (also known as "single access token") module puzzles me.
Is the user authenticated only for his current session? If he uses now the URL containing the token, can he re-use it at a later tine and still have access, or does he get a single access?
Can multiple users be authenticated at the same time, using the same token?
I have searched extensively for a working example; please forgive me if this is explained elsewhere.
Any pointers would be more than welcomed. Thanks for your help.

The short answer is: it's up to you.
This module only provides a few
helpers to help you manage the token,
but it is up to you to choose how to
use it. For example, if you want to
have a new token every time the user
saves his account, you can do the
following:
before_save :reset_authentication_token
On the other hand, if you want to
generate token unless one exists, you
should use instead:
before_save :ensure_authentication_token
If you want to delete the token after
it is used, you can do so in the
after_token_authentication callback.
See the documentation for this model at http://rdoc.info/github/plataformatec/devise/master/Devise/Models/TokenAuthenticatable.

Related

How to programmatically create keycloak user session from SPI?

I need to get access/refresh pair (or at least access) tokens from a custom REST endpoint.
So in general I need programmatically create a user session from SPI by user ID(without a user password)
Could you please suggest a better way or any examples, I'm not experienced in keycloak and I feel like missing something.
my keycloak version: 15.0.2
I think about using token_exchange and:
http://{ip}:{port}/auth/realms/{realm}/protocol/openid-connect/token
But not sure if it's will work as I expect, and if it's the best way.
If I understood correclty, you want to do user impersonation. Ie: create a token on behalf of user, without his consent.
To do that, externally to Keyckoak, you can use token exchange feature. This doc will help you: https://www.keycloak.org/docs/latest/securing_apps/#_token-exchange
Basically, the idea is that you'll give to a client permission to create tokens for any user you want.
But your question is how to do that from inside a Service Provider Interface loaded by Keycloak.
To programmatically impersonate a user, you can actually just do as the token exchange code do.
Take a look at https://github.com/keycloak/keycloak/blob/a912558d29c685ef912baa04b8cc823a70c6fd2d/services/src/main/java/org/keycloak/protocol/oidc/DefaultTokenExchangeProvider.java#L131
You'll have to create a session for the desired user and build her token.
The crux it's here https://github.com/keycloak/keycloak/blob/a912558d29c685ef912baa04b8cc823a70c6fd2d/services/src/main/java/org/keycloak/protocol/oidc/DefaultTokenExchangeProvider.java#L227

User registration/authentication flow on a REST API

I know this is not the first time the topic is treated in StackOverflow, however, I have some questions I couldn't find an answer to or other questions have opposed answers.
I am doing a rather simple REST API (Silex-PHP) to be consumed initially by just one SPA (backbone app). I don't want to comment all the several authentication methods in this question as that topic is already fully covered on SO. I'll basically create a token for each user, and this token will be attached in every request that requires authentication by the SPA. All the SPA-Server transactions will run under HTTPS. For now, my decision is that the token doesn't expire. Tokens that expire/tokens per session are not complying with the statelessness of REST, right? I understand there's a lot of room for security improvement but that's my scope for now.
I have a model for Tokens, and thus a table in the database for tokens with a FK to user_id. By this I mean the token is not part of my user model.
REGISTER
I have a POST /users (requires no authentication) that creates a user in the database and returns the new user. This complies with the one request one resource rule. However, this brings me certain doubts:
My idea is that at the time to create a new user, create a new token for the user, to immediately return it with the Response, and thus, improving the UX. The user will immediately be able to start using the web app. However, returning the token for such response would break the rule of returning just the resource. Should I instead make two requests together? One to create the user and one to retrieve the token without the user needing to reenter credentials?
If I decided to return the token together with the user, then I believe POST /users would be confusing for the API consumer, and then something like POST /auth/register appears. Once more, I dislike this idea because involves a verb. I really like the simplicity offered in this answer. But then again, I'd need to do two requests together, a POST /users and a POST /tokens. How wrong is it to do two requests together and also, how would I exactly send the relevant information for the token to be attached to a certain user if both requests are sent together?
For now my flow works like follows:
1. Register form makes a POST /users request
2. Server creates a new user and a new token, returns both in the response (break REST rule)
3. Client now attaches token to every Request that needs Authorization
The token never expires, preserving REST statelessness.
EMAIL VALIDATION
Most of the current webapps require email validation without breaking the UX for the users, i.e the users can immediately use the webapp after registering. On the other side, if I return the token with the register request as suggested above, users will immediately have access to every resource without validating emails.
Normally I'd go for the following workflow:
1. Register form sends POST /users request.
2. Server creates a new user with validated_email set to false and stores an email_validation_token. Additionally, the server sends an email generating an URL that contains the email_validation_token.
3. The user clicks on the URL that makes a request: For example POST /users/email_validation/{email_validation_token}
4. Server validates email, sets validated_email to true, generates a token and returns it in the response, redirecting the user to his home page at the same time.
This looks overcomplicated and totally ruins the UX. How'd you go about it?
LOGIN
This is quite simple, for now I am doing it this way so please correct me if wrong:
1. User fills a log in form which makes a request to POST /login sending Basic Auth credentials.
2. Server checks Basic Auth credentials and returns token for the given user.
3. Web app attached the given token to every future request.
login is a verb and thus breaks a REST rule, everyone seems to agree on doing it this way though.
LOGOUT
Why does everyone seem to need a /auth/logout endpoint? From my point of view clicking on "logout" in the web app should basically remove the token from the application and not send it in further requests. The server plays no role in this.
As it is possible that the token is kept in localStorage to prevent losing the token on a possible page refresh, logout would also imply removing the token from the localStorage. But still, this doesn't affect the server. I understand people who need to have a POST /logout are basically working with session tokens, which again break the statelessness of REST.
REMEMBER ME
I understand the remember me basically refers to saving the returned token to the localStorage or not in my case. Is this right?
If you'd recommend any further reading on this topic I'd very much appreciate it. Thanks!
REGISTER
Tokens that expire/tokens per session are not complying with the statelessness of REST, right?
No, there's nothing wrong with that. Many HTTP authentication schemes do have expiring tokens. OAuth2 is super popular for REST services, and many OAuth2 implementations force the client to refresh the access token from time to time.
My idea is that at the time to create a new user, create a new token for the user, to immediately return it with the Response, and thus, improving the UX. The user will immediately be able to start using the web app. However, returning the token for such response would break the rule of returning just the resource. Should I instead make two requests together? One to create the user and one to retrieve the token without the user needing to reenter credentials?
Typically, if you create a new resource following REST best practices, you don't return something in response to a POST like this. Doing this would make the call more RPC-like, so I would agree with you here... it's not perfectly RESTful. I'll offer two solutions to this:
Ignore this, break the best practices. Maybe it's for the best in this case, and making exceptions if they make a lot more sense is sometimes the best thing to do (after careful consideration).
If you want be more RESTful, I'll offer an alternative.
Lets assume you want to use OAuth2 (not a bad idea!). The OAuth2 API is not really RESTful for a number of reasons. I'm my mind it is still better to use a well-defined authentication API, over rolling your own for the sake of being RESTful.
That still leaves you with the problem of creating a user on your API, and in response to this (POST) call, returning a secret which can be used as an access/refresh token.
My alternative is as follows:
You don't need to have a user in order to start a session.
What you can do instead is start the session before you create the user. This guarantees that for any future call, you know you are talking to the same client.
If you start your OAuth2 process and receive your access/refresh token, you can simply do an authenticated POST request on /users. What this means is that your system needs to be aware of 2 types of authenticated users:
Users that logged in with a username/password (`grant_type = passsword1).
Users that logged in 'anonymously' and intend to create a user after the fact. (grant_type = client_credentials).
Once the user is created, you can assign your previously anonymous session with the newly created user entity, thus you don't need to do any access/refresh token exchanges after creation.
EMAIL VALIDATION
Both your suggestions to either:
Prevent the user from using the application until email validation is completed.
Allow the user to use the application immediately
Are done by applications. Which one is more appropriate really depends on your application and what's best for you. Is there any risk associated with a user starting to use an account with an email they don't own? If no, then maybe it's fine to allow the user in right away.
Here's an example where you don't want to do this: Say if the email address is used by other members of your system to add a user as a friend, the email address is a type of identity. If you don't force users to validate their emails, it means I can act on behalf of someone with a different email address. This is similar to being able to receive invitations, etc. Is this an attack vector? Then you might want to consider blocking the user from using the application until the email is validated.
You might also consider only blocking certain features in your application for which the email address might be sensitive. In the previous example, you could prevent people from seeing invitations from other users until the email is validated.
There's no right answer here, it just depends on how you intend to use the email address.
LOGIN
Please just use OAuth2. The flow you describe is already fairly close to how OAuth2 works. Take it one step further an actually use OAuth2. It's pretty great and once you get over the initial hurdle of understanding the protocol, you'll find that it's easier than you thought and fairly straightforward to just implement the bits you specifically need for your API.
Most of the PHP OAuth2 server implementations are not great. They do too much and are somewhat hard to integrate with. Rolling your own is not that hard and you're already fairly close to building something similar.
LOGOUT
The two reasons you might want a logout endpoint are:
If you use cookie/session based authentication and want to tell the server to forget the session. It sounds like this is not an issue for you.
If you want to tell the server to expire the access/refresh token earlier. Yes, you can just remove them from localstorage, and that might be good enough. Forcing to expire them server-side might give you that little extra confidence. What if someone was able to MITM your browser and now has access to your tokens? I might want to quickly logout and expire all existing tokens. It's an edge case, and I personally have never done this, but that could be a reason why you would want it.
REMEMBER ME
Yea, implementing "remember me" with local storage sounds like a good idea.
I originally took the /LOGON and /LOGOUT approach. I'm starting to explore /PRESENCE. It seems it would help me combine both knowing someone's status and authentication.
0 = Offline
1 = Available
2 = Busy
Going from Offline to anything else should include initial validation (aka require username/password). You could use PATCH or PUT for this (depending how you see it).
You are right, SESSION is not allowed in REST, hence there is no need to login or logout in REST service and /login, /logout are not nouns.
For authentication you could use
Basic authentication over SSL
Digest authentication
OAuth 2
HMAC, etc.
I prefer to use PUBLIC KEY and PRIVATE KEY [HMAC]
Private key will never be transmitted over web and I don't care about public key. The public key will be used to make the user specific actions [Who is holding the api key]
Private key will be know by client app and the server. The private key will be used to create signature. You generate a signature token using private key and add the key into the header. The server will also generate the signature and validate the request for handshake.
Authorization: Token 9944b09199c62bcf9418ad846dd0e4bbdfc6ee4b
Now how you will get private key? you have to do it manually like you put facebook, twitter or google api key on you app.
However, in some case you can also return [not recommended] the key only for once like Amazon S3 does. They provide "AWS secret access key" at the registration response.

how to use and store token from oauth2 to do authentication

sorry if this is question is too broad, but I have to ask this since I'm learning web development and I feel if don't ask I won't know.
So, I'm doing authentication using oauth2, and right now I'm already at point where I successfully authenticate user, and now I'm receiving what they call tokens. The question is, how do you use token to authenticate user to your own server?
I'm thinking something like creating a cookie that maps to a token, so when user acts, each time I'll get a cookie and I know that this is user A. Is method like this safe or not? If not, in what way people usually use the token? Although this is only a hobby project, I'd like to be "as real as possible". Any thoughts?
As per my knowledge Oauth2.0 provides InMemoryTokenStore and JdbcTokenStore for persisting tokens. When a request comes from an authenticated user Oauth2.0 will check if it has a valid token already. In case it doesn't it will create one.
Basically usage of tokens depends on the grant-type you are using . Following are the two commonly used grant types -
1) Implicit - The token is send back in the url as a parameter and is included in the subsequent request* in the parameter.
2) Authorization Code - In this case the token is generated and set in the header of the request*.
*the request here is the one which is finally sent to resource server for accessing protected resources.
I think you dont need to create a cookie for storing tokens. In case you are using Authoziation Code grant type which is the default, Oauth2.0 will use session for storing state and code which will be used for retrieving token.

Facebook Login without JSSDK, how to get token if already authorized previously

So I am updating an older desktop app (written in VB, .net 4.0) with facebook integration and followed the guide found here, and have been able to successfully get a token (by parsing the uri of the embedded webview if it contains "token="). Now my problem is if I try to login with a facebook account that has already approved the app in a prior session, the webview just gets redirected to https://www.facebook.com/connect/login_success.html without any token information.
Do I HAVE to log all of the tokens I generate manually (ie on successful token generation, I can call their profile info, use their FB ID as key and save the token)? Even if I do, since the email and password is input directly into the facebook login window, how do I check if the user already has a token?
Thanks in advance
The access token can change any time, you need to get it everytime. After getting the token, I immediately get the user information https://graph.facebook.com/me?access_token=??? and use that ID to find their database information.
I couldn't quickly find facebook information but on google's oauth information it says "The access token is also associated with a limited scope that define the kind of data the your client application has access to (for example "Manage your tasks"). An important goal for OAuth 2.0 is to provide secure and convenient access to the protected data, while minimizing the potential impact if an access token is stolen."
https://code.google.com/p/google-api-php-client/wiki/OAuth2
Ok so I finally figured it out myself. My mistake was apparently requesting the access_token directly (ie https://www.facebook.com/dialog/oauth?response_type=token...) to try and save time.
I fixed it by making a request for a 'code' instead (ie https://www.facebook.com/dialog/oauth?response_type=code), which I then use to make a second request to retrieve an access token as documented here: https://developers.facebook.com/docs/facebook-login/login-flow-for-web-no-jssdk/, "Exchanging code for an access token" section a bit lower on the page.
Hope this helps someone in the future, this was very frustrating on my part.
Regards,
Prince

Rails 3: How Does One Restrict Access to IDs

This might be very simple; I don't know Rails very well.
I have a match myController/myAction/myID in my routes.rb that will direct hyperlinks to the proper page (using link_to). But here's the problem: I don't want people to be able to freely modify the id parameter, passing in via the URL whatever they like.
Is there a way to perhaps restrict access to routes to the link_to method only? Or maybe there's another way to go about this, using a passed in hidden variable param or something?
Users access you site via urls like: /controller/action/:id right? A user can change an id and must not view another non authorized resource. How to achieve this?, on your controller, return only those resources that user is allowed to access.
For example, suppose that you are using devise:
class AController < ApplicationController
def index
#resouces = current_user.find_all_by_id params[:id]
end
end
This way if the user tries to access something he does not have access to, he will get an error.
Hope this helps, if not please let me know and I'll try to elaborate.
About current_user, yes it is supposed to be the current logged in user, it doesn't have to be devise, you can implement your own session handling logic and then create a helper method to retrieve the currently logged in user.
About using devise, if you don't want to implement your own session handling logic, plus if you want features like:
remember me
already created views that you can fully customize
authentication
authorization
password encryption
many more (please look at the docs for further information)
Then devise is a good way to go.
Also, it is always a great idea, if possible and as a learning exercise, implement your own authentication and authorization layers, you won't regret.
Best regards
Emmanuel Delgado