RFC claims that (Figure 1):
(A) The client requests authorization from the resource owner. The
authorization request can be made directly to the resource owner
(as shown), or preferably indirectly via the authorization
server as an intermediary.
Does this mean that upon request from the owner of the resource authentication protocol is not used?
Or what does it mean?
This means that the client can request the resource onwer credentials in both ways:
Directly to the resource owner, asking for user and password to the resource owner and then sending them to the authorization server,
Or preferably via the authorization server, for example when you use your google or facebook account to authenticate in a web site.
Related
I'm learning about the OAuth /introspect endpoint as a means to validate an Access Token. I'm using Okta, which I think is relevant to the question.
I've read online that the /introspect endpoint is intended to be called by an OAuth Resource Server (for example, an OAuth Client would call a Resource Server, providing an Access Token, and the Resource Server would call the /introspect endpoint to make sure the token is valid).
However, the /introspect endpoint (at least with Okta) requires you to provide the OAuth Client credentials (either as a basic auth header, or in the case where there is no client secret, just a client_id request param).
So, how can the Resource Server call the /introspect endpoint when it doesn't have the OAuth Client ID and/or secret? This is making me wonder if the /introspect endpoint is meant to be called by the OAuth Client instead, which to me, doesn't seem as useful.
Please refer to this article. Resource server needs to be a registered client application at Okta and client credentials in /introspect refer to this client's.
Based on my understanding the introspection endpoint is meant to be called by an API resource.
This endpoint is used by the API resource in order to validate the bearer token provided with an incoming HTTP request issued by a client application.
Most of the times this happens when the provided bearer token is a reference token, so the API resource server needs to known whether the provided reference token is associated with a valid access token. This information must be asked to the secure token server via a call to the introspection endpoint.
You can find more information here in the identity server docs. Identity server is a .NET implementation of the openid connect protocol, which is based itsel on oauth2.
This is a documentation that shows you how to call the introspection endpoint programmatically. This documentation is specific for a .NET library called identity model, but this is not relavant for your question, because the library simply implements the protocol.
As you can see in the example of the linked documentation, the client id that you need to specify when you call the introspection endpoint is simply the name of the API resource. The client secret is the API resource secret that you have defined for your API resource.
So, the source of your confusion is simply a terminology overload. In the context of the call to the introspection endpoint both of the following equations hold true:
client id == API resource name
client secret == API resource secret
This docs confirm both of my assumptions.
If it helps here are a few resources of mine, to add to Enrico's answer:
API Setup - see step 6 - you have to register an OAuth Client for the API
API OAuth Messages - see steps 16, 17 and 19 for the three types of response your API needs to deal with
API Code - for an example implementation in NodeJS
I am new to Oauth, can anyone explain what is the difference between Authorization code and client credentials grant type in Oauth
And also in which we need to use these two
I really appreciate the answers
The authorization code is obtained by using an authorization server as an intermediary between the
client and resource owner. Instead of requesting authorization directly from the resource owner, the
client directs the resource owner to an authorization server (via its user-agent), which in turn directs the
resource owner back to the client with the authorization code.
Before directing the resource owner back to the client with the authorization code, the authorization
server authenticates the resource owner and obtains authorization. Because the resource owner only
authenticates with the authorization server, the resource owner’s credentials are never shared with
the client.
The authorization code provides a few important security benefits, such as the ability to authenticate
the client, as well as the transmission of the access token directly to the client without passing it through
the resource owner’s user-agent and potentially exposing it to others, including the resource owner.
Client credentials are used as an authorization grant typically when the client is acting on its own behalf
(the client is also the resource owner) or is requesting access to protected resources based on an
authorization previously arranged with the authorization server.
Hope that helps.
Please refer to this video, specifically from 20.00 to 25.00.
https://azure.microsoft.com/en-us/resources/videos/new-authentication-model-for-web-mobile-and-cloud-applications/
The work flow he describes is this:
Client app connects to authorization end point through the browser. User enters credentials, and authserization server authenticates the user and sends the auth code using a re-direct. Client app intercepts the browser activity and extracts the auth code. A new request is made to token end point together with this auth code, client id and few other information. In return, app gets access and refresh token.
What stops some one from stealing the auth token in the first step (say through browser history), and then contacting the token end point to get access and refresh tokens?
First off authorization code is only good for about 3 minutes normally. Second authorization code can only be used once. Third redirect uri must be a valid one that was registered for this client on the oauth server
The client initiates the flow by directing the resource owner's
user-agent to the authorization endpoint. The client includes
its client identifier, requested scope, local state, and a
redirection URI to which the authorization server will send the
user-agent back once access is granted (or denied).
The authorization server authenticates the resource owner (via
the user-agent) and establishes whether the resource owner
grants or denies the client's access request.
Assuming the resource owner grants access, the authorization
server redirects the user-agent back to the client using the
redirection URI provided earlier (in the request or during
client registration). The redirection URI includes an
authorization code and any local state provided by the client
earlier.
The client requests an access token from the authorization
server's token endpoint by including the authorization code
received in the previous step. When making the request, the
client authenticates with the authorization server. The client
includes the redirection URI used to obtain the authorization
code for verification.
The authorization server authenticates the client, validates the
authorization code, and ensures that the redirection URI
received matches the URI used to redirect the client in
step (C). If valid, the authorization server responds back with
an access token and, optionally, a refresh token.
#section-4.1
Oauth flow
Lets do this with some correct terminology.
Client = your application
authority= identity or oauth2 server (authority)
resource owner = user whos data you wish to access.
Resource owner loads client, client notices that resource owner is not authorized. Resource owner contacts authority identifying itself using a client id and possibly a client secret and sending a redirect uri, and requests scopes. (some of the things sent depend upon the setup of the auth server)
Authority notices this resource owner is not logged in prompts them to log in. Resource owner logs in and checks what scopes the client originally requested. Prompts resource owner to grant client access to said scopes.
Resource owner consents to access. Authority returns to the client an Authorization code.
Client says nice i have an authorization code and returns to the authority the authorization code and its client id and secret. This way the Authority knows that this is in fact the client that the resource owner authorized.
Authority then returns an access token back to the client that it can use for the next hour.
Access tokens are not then re-validated. So if someone stole this access token they would be able to use it until it expires.
Generally OAuth definition says that it is way where user gives an application access to his resources stored in other application (without exposing the actual username and password). But inside Owin, it is a way to implement token based authentication within an application. Although we can deploy the Authorisation application at different server. But crux remains the same. Could anybody shed some light. I am very confused.
Thanks in advance
If you take a look at the OAuth 2.0 spec you will find this:
The authorization process utilizes two authorization server
endpoints (HTTP resources):
o Authorization endpoint - used by the client to obtain
authorization from the resource owner via user-agent redirection.
o Token endpoint - used by the client to exchange an authorization
grant for an access token, typically with client authentication.
As well as one client endpoint:
o Redirection endpoint - used by the authorization server to
return
responses containing authorization credentials to the client via
the resource owner user-agent.
Not every authorization grant type utilizes both endpoints.
Extension grant types MAY define additional endpoints as needed.
So basically, you have 2 options:
1) Use the authorization endpoint where your end-user is redirected to a form that is handled by the authorization server
OR
2) Create your own form inside your app, get the end-user credentials and send that data to the authorization server, where it will be validated and return a token for you to use.
I am trying to create oAuth 2.0 app and have decided to separate Auth server and Resource servers.
How should I go about maintaining state in Clients
Client will request for auth token to auth server. And auth server will verify and send in tokens. Till this part I understand. How should I now be using token. Should I be doing request to Resource server directly with access token and Resource server should verify that access token with Auth server? OR should I be first making request to auth server and then verify and forward request to Resource server?
The RFC (https://www.rfc-editor.org/rfc/rfc6749) suggests:
(F) The resource server validates the access token, and if valid,
serves the request.
but also that:
The interaction between the authorization server and resource server
is beyond the scope of this specification.
My instinct would be to have your resource server receive a request and then either validate the access token itself if possible - and otherwise query the auth server as necessary rather than have the auth server proxy requests.
Accessing Protected Resources
The client accesses protected resources by presenting the access
token to the resource server. The resource server MUST validate the
access token and ensure that it has not expired and that its scope
covers the requested resource. The methods used by the resource
server to validate the access token (as well as any error responses)
are beyond the scope of this specification but generally involve an
interaction or coordination between the resource server and the
authorization server.
The method in which the client utilizes the access token to
authenticate with the resource server depends on the type of access
token issued by the authorization server. Typically, it involves
using the HTTP "Authorization" request header field [RFC2617] with an
authentication scheme defined by the specification of the access
token type used, such as [RFC6750].