NAME

Plack::Auth::SSO::OIDC - implementation of OpenID Connect for Plack::Auth::SSO

STATUS

DESCRIPTION

This is an implementation of Plack::Auth::SSO to authenticate against a openid connect server.

It inherits all configuration options from its parent.

SYNOPSIS

# in your app.psi (Plack)

use strict;
use warnings;
use Plack::Builder;
use JSON;
use Plack::Auth::SSO::OIDC;
use Plack::Session::Store::File;

my $uri_base = "http://localhost:5000";

builder {

    # session middleware needed to store "auth_sso" and/or "auth_sso_error"
    # in memory session store for testing purposes
    enable "Session";

    # for authentication, redirect your users to this path
    mount "/auth/oidc" => Plack::Auth::SSO::OIDC->new(

        # plack application needs to know about the base url of this application
        uri_base => $uri_base,

        # after successfull authentication, user is redirected to this path (uri_base is used!)
        authorization_path => "/auth/callback",

        # when authentication fails at the identity provider
        # user is redirected to this path with session key "auth_sso_error" (hash)
        error_path => "/auth/error",

        # openid connect discovery url
        openid_uri => "https://example.oidc.org/auth/oidc/.well-known/openid-configuration",
        client_id => "my-client-id",
        client_secret => "myclient-secret",
        uid_key => "email"

    )->to_app();

    # example psgi app that is called after successfull authentication at /auth/oidc (see above)
    # it expects session key "auth_sso" to be present
    # here you typically create a user session based on the uid in "auth_sso"
    mount "/auth/callback" => sub {

        my $env     = shift;
        my $session = Plack::Session->new($env);
        my $auth_sso= $session->get("auth_sso");
        my $user    = MyUsers->get( $auth_sso->{uid} );
        $session->set("user_id", $user->{id});
        [ 200, [ "Content-Type" => "text/plain" ], [
            "logged in! ", $user->{name}
        ]];

    };

    # example psgi app that is called after unsuccessfull authentication at /auth/oidc (see above)
    # it expects session key "auth_sso_error" to be present
    mount "/auth/error" => sub {

        my $env = shift;
        my $session = Plack::Session->new($env);
        my $auth_sso_error = $session->get("auth_sso_error");

        [ 200, [ "Content-Type" => "text/plain" ], [
            "something happened during single sign on authentication: ",
            $auth_sso_error->{content}
        ]];

    };
};

CONSTRUCTOR ARGUMENTS

• uri_base

  See "uri_base" in Plack::Auth::SSO

• id

  See "id" in Plack::Auth::SSO

• session_key

  See "session_key" in Plack::Auth::SSO

• authorization_path

  See "authorization_path" in Plack::Auth::SSO

• error_path

  See "error_path" in Plack::Auth::SSO

• openid_uri

  base url of the OIDC discovery url.

  typically an url that ends on /.well-known/openid-configuration

• client_id

  client-id as given by the OIDC service

• client_secret

  client-secret as given by the OIDC service

• scope

  Scope requested from the OIDC service.

  Space separated string containing all scopes

  Default: "openid profile email"

  Please include scope "openid"

  cf. https://openid.net/specs/openid-connect-basic-1_0.html#Scopes

• authorize_params

  Hash reference of parameters (values must be strings) that are added to

  the authorization url. Empty by default

  e.g. { prompt => "login", "kc_idp_hint" => "orcid" }

  Note that some parameters are set internally

  and therefore will have no effect:

  • code_challenge
  • code_challenge_method
  • state
  • scope
  • client_id
  • response_type
  • redirect_uri

• allowed_authorize_params

  Array reference of parameter names.

  When constructing the authorization url,

  these parameters are copied from the current url query

  to the authorization url. This allows to add some

  dynamic configuration, but should be used with caution.

  Note that parameters from authorize_params always

  take precedence.

• uid_key

  Attribute from claims to be used as uid

  Note that all claims are also stored in $session->get("auth_sso")->{info}

HOW IT WORKS

• the openid configuration is retrieved from {openid_uri}
  • key authorization_endpoint must be present in openid configuration
  • key token_endpoint must be present in openid configuration
  • key jwks_uri must be present in openid configuration
  • the user is redirected to the authorization endpoint with extra query parameters
• after authentication at the authorization endpoint, the user is redirected back to this url with query parameters code and state. When something happened at the authorization endpoint, query parameters error and error_description are returned, and no code.
• code is exchanged for a json string, using the token endpoint. This json string is a record that contains attributes like id_token and access_token. See https://openid.net/specs/openid-connect-core-1_0.html#TokenResponse for more information.
• key id_token in the token json string contains three parts:
  • jwt jose header. Can be decoded with base64 into a json string
  • jwt payload. Can be decoded with base64 into a json string
  • jwt signature
• the jwt payload from the id_token is decoded into a json string and then to a perl hash. All this data is stored $session->{auth_sso}->{info}. One of these attributes will be the uid that will be stored at $session->{auth_sso}->{uid}. This is determined by configuration key uid_key (see above). e.g. "email"

NOTES

• Can I reauthenticate when I visit the application?

  When this Plack application is for example mounted at

  /auth/oidc, then you can reauthenticate by visiting

  it again, but it depends on your configuration what actually

  happens at the openid connect server. If prompt is not

  set anywhere (neither in authorize_params nor in the

  current url if that is allowed), then the external server

  will just sent you back with the same tokens.

  Note that session("auth_sso") is removed at the start

  of every (re)authentication.

LOGGING

All subclasses of Plack::Auth::SSO use Log::Any to log messages to the category that equals the current package name.

AUTHOR

Nicolas Franck, <nicolas.franck at ugent.be>

LICENSE AND COPYRIGHT

This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.

SEE ALSO

Plack::Auth::SSO