Thursday, June 22, 2017

SSO support for Apache Syncope REST services

Apache Syncope has recently added SSO support for its REST services in the 2.0.3 release. Previously, access to the REST services of Syncope was via HTTP Basic Authentication. From the 2.0.3 release, SSO support is available using JSON Web Tokens (JWT). In this post, we will look at how this works and how it can be configured.

1) Obtaining an SSO token from Apache Syncope

As stated above, in the past it was necessary to supply HTTP Basic Authentication credentials when invoking on the REST API. Let's look at an example using curl. Assume we have a running Apache Syncope instance with a user "alice" with password "ecila". We can make a GET request to the user self service via:
  • curl -u alice:ecila http://localhost:8080/syncope/rest/users/self
It may be inconvenient to supply user credentials on each request or the authentication process might not scale very well if we are authenticating the password to a backend resource. From Apache Syncope 2.0.3, we can instead get an SSO token by sending a POST request to "accessTokens/login" as follows:
  • curl -I -u alice:ecila -X POST http://localhost:8080/syncope/rest/accessTokens/login
The response contains two headers:
  • X-Syncope-Token: A JWT token signed according to the JSON Web Signature (JWS) spec.
  • X-Syncope-Token-Expire: The expiry date of the token
The token in question is signed using the (symmetric) "HS512" algorithm. It contains the subject "alice" and the issuer of the token ("ApacheSyncope"), as well as a random token identifier, and timestamps that indicate when the token was issued, when it expires, and when it should not be accepted before.

The signing key and the issuer name can be changed by editing '' and specifying new values for 'jwsKey' and 'jwtIssuer'. Please note that it is critical to change the signing key from the default value! It is also possible to change the signature algorithm from the next 2.0.4 release via a custom 'securityContext.xml' (see here). The default lifetime of the token (120 minutes) can be changed via the "jwt.lifetime.minutes" configuration property for the domain.

2) Using the SSO token to invoke on a REST service

Now that we have an SSO token, we can use it to invoke on a REST service instead of specifying our username and password as before. For Syncope 2.0.3 only, the header name is the same as the header name above "X-Syncope-Token". From Syncope 2.0.4 onwards, the header name is "Authorization: Bearer <token>", e.g.:
  • curl -H "Authorization: Bearer eyJ0e..." http://localhost:8080/syncope/rest/users/self
The signature is first checked on the token, then the issuer is verified so that it matches what is configured, and then the expiry and not-before dates are checked. If the identifier matches that of a saved access token then authentication is successful.

Finally, SSO tokens can be seen in the admin console under "Dashboard/Access Token", where they can be manually revoked by the admin user:

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