OIDC plugin for Kong
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pavel-mikhalchuk and Trojan295 Pass Access and ID tokens to an upstream resource (#75)
* Pass Access and ID tokens to upstream resource as headers "X-Access-Token" and "X-ID-Token" respectively
Latest commit 4df820b Dec 14, 2018

README.md

What is Kong OIDC plugin

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kong-oidc is a plugin for Kong implementing the OpenID Connect Relying Party (RP) functionality.

It authenticates users against an OpenID Connect Provider using OpenID Connect Discovery and the Basic Client Profile (i.e. the Authorization Code flow).

It maintains sessions for authenticated users by leveraging lua-resty-openidc thus offering a configurable choice between storing the session state in a client-side browser cookie or use in of the server-side storage mechanisms shared-memory|memcache|redis.

It supports server-wide caching of resolved Discovery documents and validated Access Tokens.

It can be used as a reverse proxy terminating OAuth/OpenID Connect in front of an origin server so that the origin server/services can be protected with the relevant standards without implementing those on the server itself.

Introspection functionality add capability for already authenticated users and/or applications that already posses acces token to go through kong. The actual token verification is then done by Resource Server.

How does it work

The diagram below shows the message exchange between the involved parties.

alt Kong OIDC flow

The X-Userinfo header contains the payload from the Userinfo Endpoint

X-Userinfo: {"preferred_username":"alice","id":"60f65308-3510-40ca-83f0-e9c0151cc680","sub":"60f65308-3510-40ca-83f0-e9c0151cc680"}

The plugin also sets the ngx.ctx.authenticated_consumer variable, which can be using in other Kong plugins:

ngx.ctx.authenticated_consumer = {
    id = "60f65308-3510-40ca-83f0-e9c0151cc680",   -- sub field from Userinfo
    username = "alice"                             -- preferred_username from Userinfo
}

Dependencies

kong-oidc depends on the following package:

Installation

If you're using luarocks execute the following:

 luarocks install kong-oidc

You also need to set the KONG_CUSTOM_PLUGINS environment variable

 export KONG_CUSTOM_PLUGINS=oidc

Usage

Parameters

Parameter Default Required description
name true plugin name, has to be oidc
config.client_id true OIDC Client ID
config.client_secret true OIDC Client secret
config.discovery https://.well-known/openid-configuration false OIDC Discovery Endpoint (/.well-known/openid-configuration)
config.scope oidc false OAuth2 Token scope. To use OIDC it has to contains the oidc scope
config.ssl_verify false false Enable SSL verification to OIDC Provider
config.session_secret false Additional parameter, which is used to encrypt the session cookie. Needs to be random
config.introspection_endpoint false Token introspection endpoint
config.timeout false OIDC endpoint calls timeout
config.introspection_endpoint_auth_method client_secret_basic false Token introspection auth method. resty-openidc supports `client_secret_(basic
config.bearer_only no false Only introspect tokens without redirecting
config.realm kong false Realm used in WWW-Authenticate response header
config.logout_path /logout false Absolute path used to logout from the OIDC RP

Enabling

To enable the plugin only for one API:

POST /apis/<api_id>/plugins/ HTTP/1.1
Host: localhost:8001
Content-Type: application/x-www-form-urlencoded
Cache-Control: no-cache

name=oidc&config.client_id=kong-oidc&config.client_secret=29d98bf7-168c-4874-b8e9-9ba5e7382fa0&config.discovery=https%3A%2F%2F<oidc_provider>%2F.well-known%2Fopenid-configuration

To enable the plugin globally:

POST /plugins HTTP/1.1
Host: localhost:8001
Content-Type: application/x-www-form-urlencoded
Cache-Control: no-cache

name=oidc&config.client_id=kong-oidc&config.client_secret=29d98bf7-168c-4874-b8e9-9ba5e7382fa0&config.discovery=https%3A%2F%2F<oidc_provider>%2F.well-known%2Fopenid-configuration

A successful response:

HTTP/1.1 201 Created
Date: Tue, 24 Oct 2017 19:37:38 GMT
Content-Type: application/json; charset=utf-8
Transfer-Encoding: chunked
Connection: keep-alive
Access-Control-Allow-Origin: *
Server: kong/0.11.0

{
    "created_at": 1508871239797,
    "config": {
        "response_type": "code",
        "client_id": "kong-oidc",
        "discovery": "https://<oidc_provider>/.well-known/openid-configuration",
        "scope": "openid",
        "ssl_verify": "no",
        "client_secret": "29d98bf7-168c-4874-b8e9-9ba5e7382fa0",
        "token_endpoint_auth_method": "client_secret_post"
    },
    "id": "58cc119b-e5d0-4908-8929-7d6ed73cb7de",
    "enabled": true,
    "name": "oidc",
    "api_id": "32625081-c712-4c46-b16a-5d6d9081f85f"
}

Upstream API request

The plugin adds a additional X-Userinfo header to the upstream request, which can be consumer by upstream server. It contains Userinfo base64 encoded:

GET / HTTP/1.1
Host: netcat:9000
Connection: keep-alive
X-Forwarded-For: 172.19.0.1
X-Forwarded-Proto: http
X-Forwarded-Host: localhost
X-Forwarded-Port: 8000
X-Real-IP: 172.19.0.1
Cache-Control: max-age=0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36
Upgrade-Insecure-Requests: 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: pl-PL,pl;q=0.8,en-US;q=0.6,en;q=0.4
Cookie: session=KOn1am4mhQLKazlCA.....
X-Userinfo: eyJnaXZlbl9uYW1lIjoixITEmMWaw5PFgcW7xbnEhiIsInN1YiI6ImM4NThiYzAxLTBiM2ItNDQzNy1hMGVlLWE1ZTY0ODkwMDE5ZCIsInByZWZlcnJlZF91c2VybmFtZSI6ImFkbWluIiwibmFtZSI6IsSExJjFmsOTxYHFu8W5xIYiLCJ1c2VybmFtZSI6ImFkbWluIiwiaWQiOiJjODU4YmMwMS0wYjNiLTQ0MzctYTBlZS1hNWU2NDg5MDAxOWQifQ==

Development

Running Unit Tests

To run unit tests, run the following command:

./bin/run-unit-tests.sh

This may take a while for the first run, as the docker image will need to be built, but subsequent runs will be quick.

Building the Integration Test Environment

To build the integration environment (Kong with the oidc plugin enabled, and Keycloak as the OIDC Provider), you will first need to find your computer's IP, and assign that to the environment variable IP. Finally, you will run the ./bin/build-env.sh command. Here's an example:

export IP=192.168.0.1
./bin/build-env.sh

To tear the environment down:

./bin/teardown-env.sh