Let /users/{id}
be a resource url in RESTful service.
Basic authentication is enabled and only authenticated users are allowed to access the url.
Example Scenario:
User_1
& User_2
are authenticated users with userId 1 & 2.
Since both are authenticated, both of them are having access to,
/users/1
/users/2
But the expectation is User_1
should have access to /users/1
and not to /users/2
or other userId.
Question: How to do resource level authorization in RESTful services?
Note: I am implementing RESTful using Jax-RS (with Apache CXF implementation), helpful if you could explain with Jax-RS.
-Barath
Edit:
As Donal mentioned, I am not looking for role based authorization rather resource level authorization.
To give an example, lets say /users/{id}/photos/{photoId} be another resource url. User_1 should be given access to the photos belong to him only. If photoId of 2 belonging to user_2, then we should give http_404 error code for user_1 when a request /users/1/photos/2 is requested.[Since User_1 is also authenticated user he can invoke /users/2/photos/2, so we must identify the user id based on authentication parameters than via resource url]
Only solution I can think of is, include the unique id which determines the authorization in each query like,
Instead of SELECT * FROM PHOTO_TBL WHERE PHOTO_ID=2;
use SELECT * FROM PHOTO_TBL, USER_TBL WHERE PHOTO_ID=2 AND USER_ID=1 AND USER_ID=PHOTO_ID;
with this resources are delivering data that belongs to specific user. [There should be a mechanism to prevent the modification of the unique id in client side which is used to decide on authorization(userId in this case), since all requests are STATELESS request]
Caveat: Each and every query should be intelligent enough to understand the security concerns and include extra join. This is a bad design to tie up security logic to every business function.
I am yet to look into Spring security and how it can be used in this use case.
A REST request can have a special header called Authorization Header, this header can contain the credentials (username and password) in some form. Once a request with Authorization Header is received, the server can validate the credentials and can let you access the private resources.
The fundamental concept in any RESTful API is the resource. A resource is an object with a type, associated data, relationships to other resources, and a set of methods that operate on it.
I would recommend not having the user id in the url (as if it's being 'limited' by a Basic Auth header then you may as well just have it 'specified' by the Basic auth header). This will reduce the risk of introducing a Direct Object Reference Vulnerability - https://www.owasp.org/index.php/Top_10_2010-A4-Insecure_Direct_Object_References)
In this case you could have one of the following urls:
/users/CURRENT
/me
As photos is a sub resource then you could just create the photos with a "sequence number" within the user. In a sql database this would mean having a "compound key" across both user and photo columns.
/users/CURRENT/photo/{user_photo_seq}
/me/photo/{user_photo_seq}
Your SQL would then look something like:
SELECT * FROM PHOTO_TBL WHERE USER_ID=<BasicAuthUsername> AND PHOTO_ID=<path param value>;
A good explanation of "Basic Auth Headers":
http://en.wikipedia.org/wiki/Basic_access_authentication
JAX-RS specifies sub-resource where instead of handling request in a method, processing is delegated to other object - sub-resource.
Using sub-resources it's enought to take care of the root resource and nested ones will be secured as well.
In the example you can see UserResource and all it's sub-resources available only to authorized user.
@Path("/user/{userId}")
public class UserResource {
private final String userId;
public UserResource(@PathParam("userId") String userId, @Context SecurityContext securityContext) {
this.userId = userId;
boolean authorized = /* authorization code */;
if (!authorized) { throw new WebApplicationException(Status.UNAUTHORIZED); }
}
@Path("photo")
public PhotoResource getPhotoResource() {
return new PhotoResource(userId);
}
}
public class PhotoResource {
private final String userId;
public PhotoResource(String userId) {
this.userId = userId;
}
@GET
public Response listAll() { /* ... */ }
@GET
@Path("{photoId}")
public Response present() { /* ... */ }
}
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