osiris 1.0

Pyramid based oAuth server

Introduction

Osiris (/oʊˈsaɪərɨs/) is an Egyptian god, usually identified as the god of the afterlife, the underworld and the dead. He is classically depicted as a green- skinned man with a pharaoh’s beard, partially mummy-wrapped at the legs, wearing a distinctive crown with two large ostrich feathers at either side, and holding a symbolic crook and flail. Osiris was the afterlife’s judge, he weighed the dead souls and compare them with the Feather of Truth. Those which weighed the most were sent to Ammut (the soul devourer) and not heavy enough to Aaru (the egyptian paradise).

Osiris is an oAuth 2.0 compliant server based on Pyramid. The current version (1.0) it supports the resource owner password credentials authentication flow. You can use your preferred authentication backend (LDAP, SQL, etc.) in order to oAuth enable it with Osiris. You can also use your preferred backend storage as Osiris uses a pluggable store factory to store the issued token information. The current version includes the MongoDB one.

The resource owner password credentials flow

This flow is not the most popular oAuth flow, but it’s useful in case that we want to oAuth enable an app or a set of apps in an scenario with an already existing user backend. Using this flow you can use Osiris as a gateway between your existing user store and oAuth enable it. Osiris will authenticate the user credentials against your user store and if suceeds it will issue a oAuth token. Then, an app can use it to impersonate the user’s token to access an oAuth enabled REST API, for example.

For that reason and out of the oAuth specification, Osiris features an additional endpoint to allow remote applications and resource servers to check previously issued tokens and users and validate it. This endpoint will respond if the token is valid for the user specified and if the token is not expired or revoked.

You can use Osiris as a standalone application or use it as a Pyramid plugin and make your app Osiris enabled.

Setup

This is the configuration to use it as a standalone Pyramid app, along with your own one using Paste urlmap in your app .ini:

[server:main]
use = egg:Paste#http
host = 0.0.0.0
port = 80

[composite:main]
use = egg:Paste#urlmap
/ = YOURAPP
/oauth2 = osiris

[app:osiris]
use = egg:osiris

osiris.store = osiris.store.mongodb_store
osiris.store.host = localhost
osiris.store.port = 27017
osiris.store.db = osiris
osiris.store.collection = tokens
osiris.tokenexpiry = 0

osiris.whoconfig = %(here)s/who.ini
osiris.ldap_enabled = false

[app:YOURAPP]
use = egg:YOURAPP
full_stack = true
static_files = true

You can also Osiris enable your own app, in your __init__.py:

config.include(osiris)

and in the .ini:

osiris.store = osiris.store.mongodb_store
osiris.store.host = localhost
osiris.store.port = 27017
osiris.store.db = osiris
osiris.store.collection = tokens
osiris.tokenexpiry = 0

osiris.whoconfig = %(here)s/who.ini
osiris.ldap_enabled = false

Or use it standalone (see production.ini).

Options

These are the .ini options available for Osiris:

osiris.store

Currently only available osiris.store.mongodb_store. Required.

osiris.store.host

Defaults to ‘localhost’. Optional.

osiris.store.port

Defaults to ‘27017’. Optional.

osiris.store.db

The name of the database. Defaults to ‘osiris’. Optional.

osiris.store.collection

The collection to store the tokens. Defaults to ‘tokens’. Optional.

osiris.tokenexpiry

The time in seconds that the token is valid. Defaults to 0 (unlimited). Optional.

osiris.whoconfig

The pyramid_who (repoze.who) .ini with the configuration of the authentication backends. Required.

REST API for resource owner password credentials flow

Following the oAuth 2.0 authentication standard (draft 22), the Resource owner password credentials flow must implement this web services and use these parameters:

/token

Method:

POST

Params:

grant_type

Required. Value must be set to password

username

Required. The resource owner username, encoded as UTF-8.

password

Required. The resource owner password, encoded as UTF-8.

scope

Optional. The scope of the access request.

Content-Type:

application/x-www-form-urlencoded

Response:

HTTP/1.1 200 OK Content-Type: application/json;charset=UTF-8 Cache-Control: no-store Pragma: no-cache

{ “access_token”:”Qwe1235rwersdgasdfghjkyuiyuihfgh”, “token_type”:”bearer”, “expires_in”:3600, “scope”: “exampleScope” }

/checktoken

Method:

POST

Params:

access_token

Required. Value of the token to be checked

username

Required. The resource owner username, encoded as UTF-8.

scope

Optional. The scope of the access request.

Content-Type:

application/x-www-form-urlencoded

Response:

If successful: HTTP/1.1 200 OK If not successful: HTTP/1.1 401 Unauthorized

Authentication backend

You can choose between two authentication backend plugins: pyramid_ldap and pyramid_who.

pyramid_ldap (for LDAP authentication backends)

pyramid_ldap is the defacto standard plugin when dealing with ldap in pyramid.

This is the configuration needed in the .ini to enable LDAP:

osiris.ldap_enabled = true
osiris.ldap.server = ldaps://your.ldap.uri
osiris.ldap.userbind = cn=user.to.bind,ou=users,dc=my,dc=domain
osiris.ldap.password = secret
osiris.ldap.userbasedn = ou=users,dc=my,dc=domain
osiris.ldap.userfilter = (cn=%+(login)s)
osiris.ldap.userscope = SCOPE_ONELEVEL
osiris.ldap.groupbasedn = ou=groups,dc=my,dc=domain
osiris.ldap.groupfilter = (&(objectClass=groupOfNames)(member=%+(userdn)s))
osiris.ldap.groupscope = SCOPE_SUBTREE
osiris.ldap.groupcache = 600

Adjust them to match your LDAP configuration. For further information, see: http://docs.pylonsproject.org/projects/pyramid_ldap/en/latest/

pyramid_who

pyramid_who is a plugin that provides a pluggable facility to connect with several user backends (htpass, SQL, etc.) using repoze.who plugins.

In order to use it, you should not to enable ldap:

osiris.ldap_enabled = false

and provide the path to your who.ini:

osiris.whoconfig = %(here)s/who.ini

For more information see: http://docs.repoze.org/who/2.0/

To do

Osiris features only one oAuth 2.0 authentication flow: the Resource owner password credentials (http://tools.ietf.org/html/rfc6749#section-4.3). It’s ready to accomodate the remaining flows defined by oAuth 2.0. A similar case happens with the available storage backends. The current version sports only the MongoDB storage but Osiris support the use of a plugin storage model and can accomodate more storage types.

Of course, any contribution is welcome. Please, feel free to contribute with your own storage plugins and help implementing the remaining oAuth flows.

Credits

Pluggable store factory inspired by Ben Bangert’s Velruse (https://github.com/bbangert/velruse). Borrowed error handling from pyramid- oauth2 (http://code.google.com/p/pyramid-oauth2/) by Kevin Van Wilder et al.

ChangeLog

1.0 (2013-05-19)

• Improved test coverage (91% overall, 100% on implemented parts)

• Updated implementation to be standard with the final oAuth 2.0 spec.

• Polished scopes, error handling, return codes and error messaging

• Included support for pyramid_ldap plug-in, as it has a better implementation than the repoze.who one.

• Deprecate capped collections on mongodb_store

1.0 beta1 (2012-02-22)

• Initial version