flaat 0.4.2

FLAsk support for oidc Access Tokens

FLAsk support for handling oidc Access Tokens - FLAAT

Installation

Actually the code should just run straight from github. Python dependencies include requests, flask, json and functools. Most of which are pretty standard.

Just source install.sh to get a pyve with the dependencies installed:

pip install flaat

TL;DR

FLAAT is here to provide the simplest way to verify OIDC Access Tokens. The goal is that FLAAT is a tool that can be used to very easily make access decisions or not. Priority is on ease of use, which comes with a few potential drawbacks.

Documentation

First off there's a pretty neat example.py that you can find all the examples inside. example.py provides an API via flask that is protected with flaat (FLAsk support for Access Tokens).

flaat allows protecting REST interfaces with simple decorators like:

@flaat.login_required()

flaat also supports complex group membership checking. To match two of the given groups, use:

@flaat.group_required(group=['[e-mail]', '[e-mail]', '[e-mail]'],
        claim='eduperson_scoped_affiliation', match=2)

The claim parameter allows selecting the OIDC claim in which to look for group membership.

Once started you can test calls to the example like this:

curl http://localhost:8080/valid_user -H "Authorization: Bearer `oidc-token deep`"

or

http localhost:8080/group_test_hdf "Authorization: Bearer `oidc-token unity`"

or

Please find details for usage in example.py and in the respective docstrings.

Your Bearer token can be any OIDC Access Token.

Examples

FLAAT comes with two examples:

• example.py, which is an example FLASK app. That uses the three decorators provided by FLAAT:
  • login_required
  • group_required That protect the functions they decorate You can run it like ``python3 ./example.py` You can run queries against it like:

http localhost:8080/info "Authorization: Bearer $OIDC"
http localhost:8080/valid_user "Authorization: Bearer $OIDC"
http localhost:8080/valid_user "Authorization: Bearer `oidc-token unity`"
curl localhost:8080/valid_user -H "Authorization: Bearer `oidc-token egi`"
http localhost:8080/group_test_iam "Authorization: Bearer `oidc-token google`"

• get_userinfo.py is a commandline application for testing. It uses FLAAT in a similar way as example.py Examples:

./get_userinfo.py `oidc-token indigo-iam`

What does FLAAT do?

FLAAT tries to get as much information out of the AT to determine whether or not the function it protects should be called or not.

FLAAT only operates on the OIDC Access Token, called AT.

• FLAAT firstly analyses the AT to see if the AT is a json web token (JWT). In that case there may be an exp claim, which is used.

  In case the AT is JWT, FLAAT will also query the userinfo endpoint of the OP found in the iss claim.

• For cases in which the OP cannot be determined, FLAAT offers several ways to determine the issuing OP. You can provide a list of trusted OPs, a file that cointains a list of trusted OPs, or a single OP. In the case of lists, an OP_hint can be specified, which is used to filter the available list of trusted OPs.

  Based on list and OP_hint, FLAAT queries all provided OPs for their config and then for their userinfo endpoint, to evaluate whether the AT is possibly provided by them.

  Note: For being nice to OPs that are known to issue JWTs, these are excluded from the search.

• In case the user provides a valid client_id and client_secret, the token introspection endpoint of the given OP is queried.

Issues

FLAAT works under the assumption that ATs cannot be used to access the userinfo endpoint after the AT expired. This does not seem to be the case. If you need to be strict on lifetime checking, please obtain a client_id and client_secret from the OPs that you work with.

Compatibility

Tested OIDC Providers are

• IAM of the Deep Hybrid Datacloud project -- https://iam.deep-hybrid-datacloud.eu/
• EGI -- https://aai.egi.eu/oidc/
• Unity / B2Access as used in the Helmholtz-Data-Federation -- https://unity.helmholtz-data-federation.de/oauth2/
• KIT's Shibboleth installation -- https://oidc.scc.kit.edu/auth/realms/kit/
• Google -- https://accounts.google.com/
• EduTEAMS -- https://proxy.demo.eduteams.org

Recommendation

For obtaining OIDC access tokens on the commandline you might want to use oidc-agent

License

FLAAT is provided under the MIT License