Keycloak Proxy

---

Keycloak-proxy is a proxy service which at the risk of stating the obvious integrates with the Keycloak authentication service. The configuration and feature set is based on the actual java version of the proxy. The service supports both access tokens in browser cookie or bearer tokens.

[jest@starfury keycloak-proxy]$ bin/keycloak-proxy help
NAME:
   keycloak-proxy - is a proxy using the keycloak service for auth and authorization

USAGE:
   keycloak-proxy [global options] command [command options] [arguments...]
   
VERSION:
   v0.0.6, git+sha: 73e0db2
   
AUTHOR(S):
   Rohith <gambol99@gmail.com> 
   
COMMANDS:
   help, h	Shows a list of commands or help for one command
   
GLOBAL OPTIONS:
   --config 						the path to the configuration file for the keycloak proxy
   --listen "127.0.0.1:8080"				the interface the service should be listening on
   --secret 						the client secret used to authenticate to the oauth server
   --client-id 						the client id used to authenticate to the oauth serves
   --discovery-url 					the discovery url to retrieve the openid configuration
   --upstream-url "http://127.0.0.1:8080"		the url for the upstream endpoint you wish to proxy to
   --encryption-key 					the encryption key used to encrpytion the session state
   --redirection-url 					the redirection url, namely the site url, note: /oauth will be added to it
   --hostname [--hostname option --hostname option]	a list of hostname which the service will respond to, defaults to all
   --tls-cert 						the path to a certificate file used for TLS
   --tls-private-key 					the path to the private key for TLS support
   --scope [--scope option --scope option]		a variable list of scopes requested when authenticating the user
   --claim [--claim option --claim option]		a series of key pair values which must match the claims in the token present e.g. aud=myapp, iss=http://example.com etcd
   --resource [--resource option --resource option]	a list of resources 'uri=/admin|methods=GET|roles=role1,role2'
   --signin-page 					a custom template displayed for signin
   --forbidden-page 					a custom template used for access forbidden
   --tag [--tag option --tag option]			a keypair tag which is passed to the templates when render, i.e. title='My Page',site='my name' etc
   --max-session "1h0m0s"				if refresh sessions are enabled we can limit their duration via this
   --skip-token-verification				testing purposes ONLY, the option allows you to bypass the token verification, expiration and roles are still enforced
   --proxy-protocol					switches on proxy protocol support on the listen (not supported yet)
   --refresh-sessions					enables the refreshing of tokens via offline access
   --json-logging					switch on json logging rather than text (defaults true)
   --log-requests					switch on logging of all incoming requests (defaults true)
   --verbose						switch on debug / verbose logging
   --help, -h						show help
   --version, -v					print the version

Configuration

The configuration can come from a yaml/json file and or the command line options (note, command options have a higher priority and will override any options referenced in a config file)

# is the url for retrieve the openid configuration - normally the <server>/auth/realm/<realm_name>
discovery_url: https://keycloak.example.com/auth/realms/<REALM_NAME>
# the client id for the 'client' application
clientid: <CLIENT_ID>
# the secret associated to the 'client' application
secret: <CLIENT_SECRET>
# the interface definition you wish the proxy to listen, all interfaces is specified as ':<port>'
listen: 127.0.0.1:3000
# whether to request offline access and use a refresh token
refresh_session: true
# assuming you are using refresh tokens, specify the maximum amount of time the refresh token can last
max_session: 1h
# the location of a certificate you wish the proxy to use for TLS support
tls_cert:
# the location of a private key for TLS
tls_private_key:
# the redirection url, essentially the site url, note: /oauth/callback is added at the end
redirection_url: http://127.0.0.3000
# the encryption key used to encode the session state
encryption_key: <ENCRYPTION_KEY>
# the upstream endpoint which we should proxy request
upstream: http://127.0.0.1:80
# additional scopes to add to add to the default (openid+email+profile)
scopes:
  - vpn-user

# a collection of resource i.e. urls that you wish to protect
resources:
  - url: /admin/test
    # the methods on this url that should be protected, if missing, we assuming all
    methods:
      - GET
    # a list of roles the user must have in order to accces urls under the above
    roles_allowed:
      - openvpn:vpn-user
      - openvpn:prod-vpn
      - test
  - url: /admin
    methods:
      - GET
    roles_allowed:
      - openvpn:vpn-user
      - openvpn:commons-prod-vpn

Example Usage

Assuming you have some web service you wish protected by Keycloak;

a) Create the client under the Keycloak GUI or CLI; the client protocol is 'openid-connect', access-type: confidential. b) Add a Valid Redirect URIs of http://127.0.0.1:3000/oauth/callback. c) Grab the client id and client secret. d) Create the various roles under the client or existing clients for authorization purposes.

The default config

discovery_url: https://keycloak.example.com/auth/realms/<REALM_NAME>
clientid: <CLIENT_ID>
secret: <CLIENT_SECRET>
listen: 127.0.0.1:3000
redirection_url: http://127.0.0.3000
refresh_session: false
encryption_key: AgXa7xRcoClDEU0ZDSH4X0XhL5Qy2Z2j
upstream: http://127.0.0.1:80

resources:
  - url: /admin
    methods:
      - GET
    roles_allowed:
      - <CLIENT_APP_NAME>:<ROLE_NAME>
      - <CLIENT_APP_NAME>:<ROLE_NAME>

Upstream Headers

On protected resources the upstream endpoint will receive a number of headers added by the proxy;

# add the header to the upstream endpoint
cx.Request.Header.Add("X-Auth-UserId", id.id)
cx.Request.Header.Add("X-Auth-Subject", id.preferredName)
cx.Request.Header.Add("X-Auth-Username", id.name)
cx.Request.Header.Add("X-Auth-Email", id.email)
cx.Request.Header.Add("X-Auth-ExpiresIn", id.expiresAt.String())
cx.Request.Header.Add("X-Auth-Token", id.token.Encode())
cx.Request.Header.Add("X-Auth-Roles", strings.Join(id.roles, ","))

# plus the default
cx.Request.Header.Add("X-Forwarded-For", <CLIENT_IP>)
cx.Request.Header.Add("X-Forwarded-Proto", <CLIENT_PROTO>)

Encryption Key

In order to remain stateless and not have to rely on a central cache to persist the 'refresh_tokens', the refresh token is encrypted and added as a cookie using crypto/aes. Naturally the key must be the same if your running behind a load balancer etc.

Claim Matching

Note, you can add a variable list of claim matches on the presented token by using the --claim 'key=pair' command option or a map 'claims' in the config file (see the example file), before permitting access via the proxy each of the claims inside the token are evaluated.

Custom Pages

By default the proxy will immediately redirect you for authentication and hand back 403 for access denied. Most users will probably want to present the user with a more friendly sign-in and access denied page. You can pass the command line options (or via config file) paths to the files i.e. --signin-pag=PATH. The sign-in page will have a 'redirect' passed into the scope hold the oauth redirection url. If you wish pass additional variables into the templates, perhaps title, sitename etc, you can use the --tag key=pair i.e. --tag title="This is my site"; the variable would be accessible from {{ .title }}

<html>
<body>
<a href="{{ .redirect }}">Sign-in</a>
</body>
</html>