Difference between Access Grant and Access Token - ruby-on-rails

I can't figure out the difference between Token and Grant in Doorkeeper. In which moment, Doorkeeper creates an Access Grant and when an Access Token? The documentation doesn't seems to say nothing about it and now I'm reading the code but is not a dozen lines.

I recommend to also read the documentation of oauth2
As I understand, Doorkeeper is based on the protocol described in that documentation too.
In doorkeeper, you will get access grant first and then access token.
Access grant usually only lives very short (the default in doorkeeper is 10 minutes).
You will get this by requesting GET to api-url/oauth/authorize (don't forget to put client_id, redirect_uri, and response_type as parameter. response_type will have value "code").
Once user allow the apps (user clicks "allow" button), doorkeeper will return the access grant as parameter in the returning url.
Get that code and you can now use it to make POST request to api-url/oauth/token to get your access_token and refresh_token.
Using access_token, you can get the resources of the API in a limited time (Doorkeeper's default is one hour if I'm not mistaken).
When acces_tooken expired, use refresh_token to get new access_token and so on.
In summary, access grant is the key that given as the sign that user has allowed the apps to use its resources.
Access token is the key that is given to permit an apps to use resources in a limited time which has defined.
Hope it can help.

I'm assuming you're talking about the Web Server flow, as you're using a Ruby gem in a Rails app (as you know, there are 4 flows).
Usually in the Web Server flow, Grant is the moment when the user clicks in a link to consent authorization: he/she will be asked to authorize the app to read/write data.
If consent is granted, then the app will get a temp code. With this code, in the background, the app will ask the Token for the service provider.
Then, only with the Token, the app will be able to use the service provider APIs.

Related

Doorkeeper OAuth application table is necessary for authorization?

I'm trying to add the Doorkeeper plus devise with google and facebook user authorization on API!
I followed this post https://www.vic-l.com/jwt-with-refresh-token-using-devise-and-doorkeeper-without-authorization
And this:
https://naturaily.com/blog/api-authentication-devise-doorkeeper-setup
To start with, both remove the oauth_applications table.
I've done as the tutorials but I'm getting this response:
response_code: "doorkeeper.errors.messages.unsupported_grant_type",…}
response_code: "doorkeeper.errors.messages.unsupported_grant_type"
response_message: "The authorization grant type is not supported by the authorization server."
state: nul
So I would like to know if is necessary the oauth_applications table and set the clients to authorize.
Articles you've mentioned uses Resource Owner Password Flow, i.e they are authenticating the user via credentials to give an access to a resources with an access token. See the configuration option:
grant_flows %w[password]
In such case yeah, you don't need applications (clients which will interact with the API). But if you want to show an authorization window for your customers you should use Authorization Code Flow (from your response I see you're trying to invoke exactly this flow).

JWT: what is the advantage of a refresh token when using grant_type=password

I'm following this article to understand refesh tokens.
In my case I have to connect to REST api using grant_type=password, and I receive a token with a 5 minute lifespan. So every 5 minutes I have to issue a POST request passing client-id, username & password to get a new acces token.
The other option would be to issue a POST with a grant_type=refresh_token, without having to send the username & password. In my case I'm consuming an api, so passing the credentials doesn't involve any action from the final user. For me it's just to params more to send on the POST request.
In both cases, I have to issue a new post every 5 minutes.
Is that the only advantage (not needing to pass credentials again) of using the reresh token or is there any other thing I'm missing?
Background info
OAuth 2.0 Password Grant
The Password grant type is a way to exchange a user's credentials for an access token. Because the client application has to collect the user's password and send it to the authorization server, it is not recommended that this grant be used at all anymore.
OAuth 2.0 Refresh Token
The Refresh Token grant type is used by clients to exchange a refresh token for an access token when the access token has expired.
This allows clients to continue to have a valid access token without further interaction with the user.
Consider this.
Lets say that i add my login and password for my twitter account to your application and you then use that to request access from twitter to may account to post. Three months later i have forgotten i have set your awesome app up to do something on my twitter account and i change my password. Your system will break.
Now lets say i used Oauth2 to grant you access to my Google drive account, your awesome app can now do what ever it needs to do on my drive account. Now three months latter i have again forgotten i gave your awesome app access, I have the memory of a gold fish you see. I change my password. Nothing happens your awesome app still has access.
Now consider this, With oauth2 i can grant you access to only read from my google drive account not update it (scope). That and the system knows its not actually me preforming the actions.
With client login (login and password) most of the time it appears to the system that it is the actually owner of the account making the requests. You can also not limit access with client login for the most part you have full access.
note
yes i am ignoring the part about both tokens returned being the expiration time time. Thats because for all intensive purposes they are the same but that depends greatly on how the auth server you are using is set up. They could be set up to only be valid for an hour or a day. They may give you different access scopes, again this differs greatly from auth server to auth server.

Refreshed Token could be revoked 50 times per account

I tried to add YouTube Video from the third party and After one day, I got the success in doing so. But While uploading a video the access token is required and in order to get that access token the user must be logged in. And the expiration time for that access token is 3600 seconds( 1 hr).
Now, There are some of my questions regarding this.
Is there anyway, by which I can refresh access token.
If some one has G Suite account, then Is there any special values for expiration time, or it remains the same?
As per the documentation, I can have maximum 50 tokens, So is there any alternative for it, So that I can get valid token after 50 requests.
To answer your question for number 1, you can check the documentation here.
Access tokens periodically expire. You can refresh an access token
without prompting the user for permission (including when the user is
not present) if you requested offline access to the scopes associated
with the token.
If you use a Google API Client Library, the client object refreshes the access token as needed as long as you configure that
object for offline access.
If you are not using a client library, you need to set the access_type HTTP query parameter to offline when redirecting the
user to Google's OAuth 2.0 server. In that case, Google's
authorization server returns a refresh token when you exchange an
authorization code for an access token. Then, if the access token
expires (or at any other time), you can use a refresh token to obtain
a new access token.
Requesting offline access is a requirement for any application that
needs to access a Google API when the user is not present. For
example, an app that performs backup services or executes actions at
predetermined times needs to be able to refresh its access token when
the user is not present. The default style of access is called online.
About the G Suite account, it was stated 24 Hours in the documentation. Note:
In this SO post answer, the function of Access Token and Refresh Token was discussed.
I am not sure if there are ways to alter the limits because of security reasons.
To clearly differentiate these two tokens and avoid getting mixed up,
here are their functions given in The OAuth 2.0 Authorization
Framework:
Access Tokens are issued to third-party clients by an authorization server with the approval of the resource owner. The
client uses the access token to access the protected resources hosted
by the resource server.
Refresh Tokens are credentials used to obtain access tokens. Refresh tokens are issued to the client by the authorization server
and are used to obtain a new access token when the current access
token becomes invalid or expires, or to obtain additional access
tokens with identical or narrower scope.

3-legs in OAuth 2.0

I'm making a program uses Youtube API for testing purpose.
Because my program is an installed-application, I've found a picture pointing out how to implement authentication.
It's what I have:
Immediately, I'm confused. According to this figure, I don't know why Google Servers just returns Authorization code after User login and consent.
Why doesn't Google Servers return Token instantly?
You are Confused because, I guess, you have missed 3rd leg "User". Authorization code represents the User Consent.
Google server returns Authorization code when User grants the permission to your app to get his/her data from google server(resource server). if user denies the permission Google server wont generate the Authorization code and your app wont be able to get access token.
Another use of Authorization_code is to keep resource owners credentials secret. Authorization code is shared with client and client exchanged that code for access_token.
Find more Information about Oauth 2.0 in this article.

Is function of authorization code and refresh token duplicated in design of oauth2?

there's two ways to fetch access token.
use authorization code to exchange it
use refresh token to refresh it
think about it!!
though the word of exchange and refresh is different,what they do are the same.
both action need to parse client id & client secret(Or signature) and token
we can just save the authorization code in our system,and again use auth code to
refresh access token just like refresh token do.
Except that authorization code is expired too soon.
so I wonder
why the designers of oauth2 designed these two concepts while not used just one single concept or say just design the authorization code and give it a long expired-time.
I am afraid that you have not understood the concepts of oauth2 too well. There aren't just two ways of getting the access token, there are more. Each is basically called a 'grant type'. I'm describing the use cases of the ones which I have deployed below :
1- Authorization code :
This is similar to the flow of "Login with Facebook" etc buttons which you see on different websites, which allow you to register/login using your facebook etc accounts. Here, on clicking this button, control is directed to Facebook, where the user enters his login credentials. If successful, an authorization code is sent to whatever redirecturl you entered while registering as a developer with Facebook. You then use this authorization code to request the access token service to get the access token which you then use whenever accessing any Facebook webservices to get the user's details.
2- Client credentials :
If you are running your own webservices and you want to allow access only to valid clients, then this is the grant type you would use. For example, you are running your webservices and now you want to consume it in your own native mobile app which you distribute through any app store. This will ensure that only those who installed your app will be able to access your webservice.
3- User credentials :
Same as above, only in this case this would allow you to authenticate a registered user as well and then give access to user restricted services like my account etc.
4- Refresh token :
By design, the access token service gives an access token as well as a refresh token. You would use the refresh token obtained from it here to refresh an expired access token. Essentially, this does not generate a new access token, it only "refreshes" an existing token. It will give you a new access token and refresh token and extend the expiry time. When this access token expires, you again call refresh token using the refresh token obtained last time, and keep repeating the process every time the token expires.
According to RFC 6749 10.5 The authorization codes are short lived and single-use. Therefore, you cannot use them again and again to get new authorization tokens.
Authorization codes MUST be short lived and single-use. If the
authorization server observes multiple attempts to exchange an
authorization code for an access token, the authorization server
SHOULD attempt to revoke all access tokens already granted based on
the compromised authorization code.
There are some additional misconceptions that seem to be presented here, so I wanted to help clear them up.
The differences between an access token and a refresh token can be summarised as follows:
An access token is used to provide access to restricted resources to an authorized client after authentication has taken place.
A refresh token, on the other hand, is used by a client in order to retrieve new access tokens with identical or narrower scopes.
The different between the Authorization Code Grant and the Implicit Grant (as well as their usages) help to illustrate how both should be used.
In general, the Authorization Code Grant should be preferred over the Implicit Grant unless a resource is being accessed directly via a publicly implemented client (e.g., browser-run code) or there is a specific reason that the Authorization Code Grant cannot be used (e.g., feasibility or performance). This is explained in the RFC definition for the Implicit flow.
During an Implicit Grant, access tokens are exposed to the user-agent which could lead to them being compromised since they are no longer under the control of a server app (confidential client) that could otherwise be requesting the protected resources. This is why refresh tokens are not issued during Implicit Grants. Though access tokens might be exposed, they are short-lived. Resource tokens, on the other hand, are long-lived and can be used to retrieve new access tokens.
The Authorization Code Grant, on the other hand, prevents the potential for refresh tokens to be exposed. During this grant, the authorisation server issues a code instead of tokens. The code is then passed by the user-agent to the client application which exchanges the code with the authorization server to retrieve access and refresh tokens. Since the code exchange is performed directly between the client application and a trusted authorization server, a refresh token can be securely issued.
The RFC spec cautions that the security implications of implementing the Authorization Code Grant in a public client versus a confidential (e.g., server-side) client should be seriously considered. "More OAuth 2.0 Surprises: The Refresh Token" clears up a few misconceptions and furthers the idea that auth codes should not be sent directly by the user-agent to the auth server in order to retrieve refresh tokens, though the OAuth 2.0 spec does not technically dictate this.
Answer from #ComfortableDust has the answer to original question. Just quoting the exact text from his reply
The Authorization Code Grant, on the other hand, prevents the potential for refresh tokens to be exposed. During this grant, the authorisation server issues a code instead of tokens. The code is then passed by the user-agent to the client application which exchanges the code with the authorization server to retrieve access and refresh tokens. Since the code exchange is performed directly between the client application and a trusted authorization server, a refresh token can be securely issued.

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