How to Bootstrap an OAuth2 Authorization Server With UAA
Leveraging Cloud Foundry's UAA project can help get you started with putting up an OAuth2 authorization server — one that's lightweight but still very scalable.
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I will cover using the UAA in two posts. In this post, I will go over how to get a local UAA server running and populate it with some of the actors involved in an OAuth2 authorization_code flow (i.e., clients and users), and in a follow-up post, I will show how to use thisauthorization server with a sample client application and in securing a resource.
Starting Up the UAA
The repository for the UAA project is here. Downloading the project is simple. Just clone this repo:
git clone https://github.com/cloudfoundry/uaa
If you have a local JDK available, start it up using:
This version of UAA uses an in-memory database, so the test data generated will be lost on restart of the application.
Populate Some Data
An awesome way to interact with UAA is its companion CLI application, UAAC. Assuming that you have the UAAC CLI downloaded and UAA started up on its default port of 8080, let us start by pointing the UAAC to the UAA application:
uaac target http://localhost:8080/uaa
Log into it using one of the canned client credentials (
uaac token client get admin -s adminsecret
Now that a client has logged in, the token can be explored using:
This would display the details of the token issued by UAA along these lines:
*[http://localhost:8080/uaa] *[admin] client_id: admin access_token: eyJhbGciOiJIUzI1NiJ9.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.B-RmeIvYttxJOMr_CX1Jsinsr6G_e8dVU-Fv-3Qq1ow token_type: bearer expires_in: 43199 scope: clients.read clients.secret clients.write uaa.admin clients.admin scim.write scim.read jti: d99b2850-bd45-4e97-822e-74a62e07f4c5
To see a more readable and decoded form of the token, just run:
uaac token decode
Doing so should display a decoded form of the token:
jti: d99b2850-bd45-4e97-822e-74a62e07f4c5 sub: admin authorities: clients.read clients.secret clients.write uaa.admin clients.admin scim.write scim.read scope: clients.read clients.secret clients.write uaa.admin clients.admin scim.write scim.read client_id: admin cid: admin azp: admin grant_type: client_credentials rev_sig: e78b0213 iat: 1487039776 exp: 1487082976 iss: http://localhost:8080/uaa/oauth/token zid: uaa aud: admin clients uaa scim
Now, to create a brand new client (
client1), which I will be using in a follow-up post:
uaac client add client1 \ --name client1 --scope resource.read,resource.write \ --autoapprove ".*" \ -s client1 \ --authorized_grant_types authorization_code,refresh_token,client_credentials \ --authorities uaa.resource
This client is going to request a scope of
resource.write from users and will participate in authorization_code grant-type OAuth2 flows, creating a resource owner or a user of the system:
uaac user add user1 -p user1 --emails firstname.lastname@example.org
...and assigning this user a
uaac group add resource.read uaac member add resource.read user1
Exercise a Test Flow
Now that we have a client and a resource owner, let us exercise a quick authorization_code flow, uaac provides a handy command line option that provides the necessary redirect hooks to capture auth code and transforms the auth_code to an access token.
uaac token authcode get -c client1 -s client1 --no-cf
Invoking the above command should open up a browser window and prompt for user creds:
Logging in with the
user1 user that was created previously should respond with a message in the command line that the token has been successfully fetched. This can be explored once more using the following command:
...with the output showing the details of the logged-in user:
jti: c8ddfdfc-9317-4f16-b3a9-808efa76684b nonce: 43c8d9f7d6264fb347ede40c1b7b44ae sub: 7fdd9a7e-5b92-42e7-ae75-839e21b932e1 scope: resource.read client_id: client1 cid: client1 azp: client1 grant_type: authorization_code user_id: 7fdd9a7e-5b92-42e7-ae75-839e21b932e1 origin: uaa user_name: user1 email: email@example.com auth_time: 1487040497 rev_sig: c107f5c0 iat: 1487040497 exp: 1487083697 iss: http://localhost:8080/uaa/oauth/token zid: uaa aud: resource client1
This concludes the whirlwind tour of setting up a local UAA and adding a couple of roles involved in an OAuth2 flow (a client and a user). I have not covered the OAuth2 flows itself; the article Digital Ocean Intro to OAuth2 is a very good primer on the flows.
I will follow this post with a post on how this infrastructure can be used for securing a sample resource and demonstrate a flow using Spring Security and Spring Boot.
Published at DZone with permission of Biju Kunjummen. See the original article here.
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