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What is Kong OIDC plugin

Continuous Integration: <br/>

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:

lua-resty-openidc

Installation

If you're using luarocks execute the following:

 luarocks install kong-oidc

You also need to set the KONG_PLUGINS environment variable

 export KONG_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`	openid	false	OAuth2 Token scope. To use OIDC it has to contains the `openid` 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, X-Access-Token and X-Id-Token headers to the upstream request, which can be consumer by upstream server. All of them are 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==
X-Access-Token: eyJhbGciOiJSUzI1NiIsInR5cCIgOiAiSldUIiwia2lkIiA6ICJGenFSY0N1Ry13dzlrQUJBVng1ZG9sT2ZwTFhBNWZiRGFlVDRiemtnSzZRIn0.eyJqdGkiOiIxYjhmYzlkMC1jMjlmLTQwY2ItYWM4OC1kNzMyY2FkODcxY2IiLCJleHAiOjE1NDg1MTA4MjksIm5iZiI6MCwiaWF0IjoxNTQ4NTEwNzY5LCJpc3MiOiJodHRwOi8vMTkyLjE2OC4wLjk6ODA4MC9hdXRoL3JlYWxtcy9tYXN0ZXIiLCJhdWQiOlsibWFzdGVyLXJlYWxtIiwiYWNjb3VudCJdLCJzdWIiOiJhNmE3OGQ5MS01NDk0LTRjZTMtOTU1NS04NzhhMTg1Y2E0YjkiLCJ0eXAiOiJCZWFyZXIiLCJhenAiOiJrb25nIiwibm9uY2UiOiJmNGRkNDU2YzBjZTY4ZmFmYWJmNGY4ZDA3YjQ0YWE4NiIsImF1dGhfdGltZSI6…IiwibWFuYWdlLWFjY291bnQtbGlua3MiLCJ2aWV3LXByb2ZpbGUiXX19LCJzY29wZSI6Im9wZW5pZCBwcm9maWxlIGVtYWlsIiwiZW1haWxfdmVyaWZpZWQiOmZhbHNlLCJwcmVmZXJyZWRfdXNlcm5hbWUiOiJhZG1pbiJ9.GWuguFjSEDGxw_vbD04UMKxtai15BE2lwBO0YkSzp-NKZ2SxAzl0nyhZxpP0VTzk712nQ8f_If5-mQBf_rqEVnOraDmX5NOXP0B8AoaS1jsdq4EomrhZGqlWmuaV71Cnqrw66iaouBR_6Q0s8bgc1FpCPyACM4VWs57CBdTrAZ2iv8dau5ODkbEvSgIgoLgBbUvjRKz1H0KyeBcXlVSgHJ_2zB9q2HvidBsQEIwTP8sWc6er-5AltLbV8ceBg5OaZ4xHoramMoz2xW-ttjIujS382QQn3iekNByb62O2cssTP3UYC747ehXReCrNZmDA6ecdnv8vOfIem3xNEnEmQw
X-Id-Token: eyJuYmYiOjAsImF6cCI6ImtvbmciLCJpYXQiOjE1NDg1MTA3NjksImlzcyI6Imh0dHA6XC9cLzE5Mi4xNjguMC45OjgwODBcL2F1dGhcL3JlYWxtc1wvbWFzdGVyIiwiYXVkIjoia29uZyIsIm5vbmNlIjoiZjRkZDQ1NmMwY2U2OGZhZmFiZjRmOGQwN2I0NGFhODYiLCJwcmVmZXJyZWRfdXNlcm5hbWUiOiJhZG1pbiIsImF1dGhfdGltZSI6MTU0ODUxMDY5NywiYWNyIjoiMSIsInNlc3Npb25fc3RhdGUiOiJiNDZmODU2Ny0zODA3LTQ0YmMtYmU1Mi1iMTNiNWQzODI5MTQiLCJleHAiOjE1NDg1MTA4MjksImVtYWlsX3ZlcmlmaWVkIjpmYWxzZSwianRpIjoiMjI1ZDRhNDItM2Y3ZC00Y2I2LTkxMmMtOGNkYzM0Y2JiNTk2Iiwic3ViIjoiYTZhNzhkOTEtNTQ5NC00Y2UzLTk1NTUtODc4YTE4NWNhNGI5IiwidHlwIjoiSUQifQ==

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