keycloak-gatekeeper

README

Keycloak Proxy

---

• Supports role based uri controls
• Web Socket connection upgrading
• Token claim matching for additional ACL controls
• Custom claim injections into authenticated requests
• Stateless offline refresh tokens with optional predefined session limits
• TLS and mutual TLS support
• JSON field bases access logs
• Custom Sign-in and access forbidden pages
• Forward Signed Proxy
• URL Role Tokenization
• Listen on unix sockets, proxy upstream to unix sockets

---

Keycloak-proxy is a proxy service which at the risk of stating the obvious integrates with the Keycloak authentication service. Although technically the service has no dependency on Keycloak itself and would quite happily work with any OpenID provider. 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 [options]

VERSION:
   v1.2.0 (git+sha: fc38244)

AUTHOR(S):
   Rohith <gambol99@gmail.com>

COMMANDS:
GLOBAL OPTIONS:
   --config value                       the path to the configuration file for the keycloak proxy [$PROXY_CONFIG_FILE]
   --listen value                       the interface the service should be listening on (default: "127.0.0.1:3000")
   --client-secret value                the client secret used to authenticate to the oauth server (access_type: confidential) [$PROXY_CLIENT_SECRET]
   --client-id value                    the client id used to authenticate to the oauth service [$PROXY_CLIENT_ID]
   --discovery-url value                the discovery url to retrieve the openid configuration [$PROXY_DISCOVERY_URL]
   --scope value                        a variable list of scopes requested when authenticating the user
   --token-validate-only                validate the token and roles only, no required implement oauth
   --idle-duration value                the expiration of the access token cookie, if not used within this time its removed (default: 0)
   --redirection-url value              redirection url for the oauth callback url (/oauth is added) [$PROXY_REDIRECTION_URL]
   --revocation-url value               the url for the revocation endpoint to revoke refresh token (default: "/oauth2/revoke")
   --store-url value                    url for the storage subsystem, e.g redis://127.0.0.1:6379, file:///etc/tokens.file [$PROXY_STORE_URL]
   --upstream-url value                 the url for the upstream endpoint you wish to proxy to [$PROXY_UPSTREAM_URL]
   --upstream-keepalives                enables or disables the keepalive connections for upstream endpoint
   --upstream-timeout value             is the maximum amount of time a dial will wait for a connect to complete (default: 10s)
   --upstream-keepalive-timeout value   specifies the keep-alive period for an active network connection (default: 10s)
   --enable-refresh-tokens              enables the handling of the refresh tokens
   --secure-cookie                      enforces the cookie to be secure, default to true
   --cookie-access-name value           the name of the cookie use to hold the access token (default: "kc-access")
   --cookie-refresh-name value          the name of the cookie used to hold the encrypted refresh token (default: "kc-state")
   --encryption-key value               the encryption key used to encrpytion the session state
   --no-redirects                       do not have back redirects when no authentication is present, 401 them
   --hostname value                     a list of hostnames the service will respond to, defaults to all
   --enable-proxy-protocol              whether to enable proxy protocol
   --enable-forwarding                  enables the forwarding proxy mode, signing outbound request
   --forwarding-username value          the username to use when logging into the openid provider
   --forwarding-password value          the password to use when logging into the openid provider
   --forwarding-domains value           a list of domains which should be signed, anything is just relayed
   --tls-cert value                     the path to a certificate file used for TLS
   --tls-private-key value              the path to the private key for TLS support
   --tls-ca-certificate value           the path to the ca certificate used for mutual TLS
   --skip-upstream-tls-verify           whether to skip the verification of any upstream TLS (defaults to true)
   --match-claims value                 keypair values for matching access token claims e.g. aud=myapp, iss=http://example.*
   --add-claims value                   retrieve extra claims from the token and inject into headers, e.g given_name -> X-Auth-Given-Name
   --resource value                     a list of resources 'uri=/admin|methods=GET|roles=role1,role2'
   --headers value                      Add custom headers to the upstream request, key=value
   --signin-page value                  a custom template displayed for signin
   --forbidden-page value               a custom template used for access forbidden
   --tag value                          keypair's passed to the templates at render,e.g title='My Page'
   --cors-origins value                 list of origins to add to the CORE origins control (Access-Control-Allow-Origin)
   --cors-methods value                 the method permitted in the access control (Access-Control-Allow-Methods)
   --cors-headers value                 a set of headers to add to the CORS access control (Access-Control-Allow-Headers)
   --cors-exposes-headers value         set the expose cors headers access control (Access-Control-Expose-Headers)
   --cors-max-age value                 the max age applied to cors headers (Access-Control-Max-Age) (default: 0)
   --cors-credentials                   the credentials access control header (Access-Control-Allow-Credentials)
   --enable-security-filter             enables the security filter handler
   --skip-token-verification            TESTING ONLY; bypass token verification, only expiration and roles enforced
   --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

Building

Assuming you have make + go, simply run make (or 'make static' for static linking). You can also build via docker container: make docker-build

Configuration

Configuration can come from a yaml/json file and or the command line options (note, command options have a higher priority and will override or merge 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
client-id: <CLIENT_ID>
# the secret associated to the 'client' application
client-secret: <CLIENT_SECRET>
# the interface definition you wish the proxy to listen, all interfaces is specified as ':<port>', unix sockets as unix://<REL_PATH>|</ABS PATH>
listen: 127.0.0.1:3000
# whether to enable refresh tokens
enable-refresh-token: true
# 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://127.0.0.1:3000
# the encryption key used to encode the session state
encryption-key: <ENCRYPTION_KEY>
# the upstream endpoint which we should proxy request
upstream-url: 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 access urls under the above
  # If all you want is authentication ONLY, simply remove the roles array - the user must be authenticated but
  # no roles are required
  roles:
  - openvpn:vpn-user
  - openvpn:prod-vpn
  - test
- url: /admin
  methods:
  - GET
  roles:
  - openvpn:vpn-user
  - openvpn:commons-prod-vpn

Example Usage

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

• Create the client under the Keycloak GUI or CLI; the client protocol is 'openid-connect', access-type: confidential.
• Add a Valid Redirect URIs of http://127.0.0.1:3000/oauth/callback.
• Grab the client id and client secret.
• 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>
client-id: <CLIENT_ID>
client-secret: <CLIENT_SECRET> # require for access_type: confidential
listen: 127.0.0.1:3000
redirection-url: http://127.0.0.1:3000
encryption_key: AgXa7xRcoClDEU0ZDSH4X0XhL5Qy2Z2j
upstream-url: http://127.0.0.1:80
resources:
- url: /admin
  methods:
  - GET
  roles:
  - client:test1
  - client:test2
- url: /backend
  roles:
  - client:test1

Note, anything defined in the configuration file can also be configured as command line options, so the above would be reflected as;

bin/keycloak-proxy \
    --discovery-url=https://keycloak.example.com/auth/realms/<REALM_NAME> \
    --client-id=<CLIENT_ID> \
    --client-secret=<SECRET> \
    --listen=127.0.0.1:3000 \ # unix sockets format unix://path
    --redirection-url=http://127.0.0.1:3000 \
    --enable-refresh-token=true \
    --encryption-key=AgXa7xRcoClDEU0ZDSH4X0XhL5Qy2Z2j \
    --upstream-url=http://127.0.0.1:80 \
    --resource="uri=/admin|methods=GET|roles=test1,test2" \
    --resource="uri=/backend|roles=test1"

- Google OAuth

---

Although the role extensions do require a Keycloak IDP or at the very least a IDP that produces a token which contains roles, there's nothing stopping you from using it against any OpenID providers, such as Google. Go to the Google Developers Console and create a new application (via "Enable and Manage APIs -> Credentials). Once you've created the application, take the client id, secret and make sure you've added the callback url to the application scope (using the default this would be http://127.0.0.1:3000/oauth/callback)

bin/keycloak-proxy \
    --discovery-url=https://accounts.google.com/.well-known/openid-configuration \
    --client-id=<CLIENT_ID> \
    --client-secret=<CLIENT_SECRET> \
    --resource="uri=/" \   
    --verbose=true

Open a browser an go to http://127.0.0.1:3000 and you should be redirected to Google for authenticate and back the application when done and you should see something like the below.

DEBU[0002] resource access permitted: /                  access=permitted bearer=false expires=57m51.32029042s resource=/ username=gambol99@gmail.com
2016-02-06 13:59:01.680300 I | http: proxy error: dial tcp 127.0.0.1:8081: getsockopt: connection refused
DEBU[0002] resource access permitted: /favicon.ico       access=permitted bearer=false expires=57m51.144004098s resource=/ username=gambol99@gmail.com
2016-02-06 13:59:01.856716 I | http: proxy error: dial tcp 127.0.0.1:8081: getsockopt: connection refused

- Forward Signing Proxy (Experimental)

Forward signing provides a mechanism for authentication and authorization between services, using the keycloak issued tokens for granular control. When operating with in the more, the proxy will automatically acquire a access token (handling the refreshing or logins) and tag Authorization headers on outbound request's (TLS via HTTP CONNECT is fully supported). You control which domains are tagged by the --forwarding-domains option. Note, this option use a contains comparison on domains. So, if you wanted to match all domains under *.svc.cluster.local can and simply use: --forwarding-domain=svc.cluster.local.

At present the service logs in using oauth client_credentials grant type, so your authentication service, must support direct (username/password) logins.

Example setup:

You have collection of micro-services which are permitted to speak to one another; you've already setup the credentials, roles, clients etc in Keycloak, providing granular role controls over issue tokens.

# kubernetes pod example
- name: keycloak-proxy
  image: quay.io/gambol99/keycloak-proxy:latest
  args:
  - --enable-forwarding=true
  - --forwarding-username=projecta
  - --forwarding-password=some_password 
  - --forwarding-domains=projecta.svc.cluster.local
  - --forwarding-domains=projectb.svc.cluster.local
  # Note: if you don't specify any forwarding domains, all domains will be signed; Also the code checks is the
  # domain 'contains' the value (it's not a regex) so if you wanted to sign all requests to svc.cluster.local, just use
  # svc.cluster.local
  volumeMounts:
  - name: keycloak-socket
    mountPoint: /var/run/keycloak
- name: projecta
  image: some_images
  
# test the forward proxy  
[jest@starfury keycloak-proxy]$ curl -k --proxy http://127.0.0.1:3000 https://test.projesta.svc.cluster.local

Receiver side you could setup the keycloak-proxy (--no=redirects=true) and permit this proxy to verify and handle admission for you. Alternatively, the access token can found as a bearer token in the request.

- URL Tokenization (in-progress)

---

You can tokenize the url for an authenticated resource, extracting roles from the url itself. Say for example you have an applications where the uri comes in a namespace form, e.g. /logs/ i.e. logs/admin/, logs/app1, logs/app2 etc. you could use

resources:
- uri: logs/admin
  roles: [ 'admin' ]
- uri: logs/app1
  roles: [ 'app1' ]
- uri: logs/app2
  roles: [ 'app2' ]

But it could become annoying, creating roles for namespaces, updating there, then updating config here. An easier way would be map a url token to a role name. i.e.

resources:
- uri: logs/%role%/

The above will extract role requirement from the url and apply to admission as per usual. /logs/admin will need a admin role, logs/app1 needs the app1 role, etc.

---

- Upstream Headers

On protected resources the upstream endpoint will receive a number of headers added by the proxy, along with an custom claims.

# add the header to the upstream endpoint
id := user.(*userContext)
cx.Request.Header.Add("X-Auth-Userid", id.name)
cx.Request.Header.Add("X-Auth-Subject", id.id)
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, ","))
cx.Request.Header.Set("Authorization", fmt.Sprintf("Bearer %s", id.token.Encode()))

# plus the default
cx.Request.Header.Add("X-Forwarded-For", cx.Request.RemoteAddr)
cx.Request.Header.Add("X-Forwarded-Proto", <CLIENT_PROTO>)
cx.Request.Header.Set("X-Forwarded-Agent", prog)
cx.Request.Header.Set("X-Forwarded-Agent-Version", version)
cx.Request.Header.Set("X-Forwarded-Host", cx.Request.Host)

- Custom Claims

You can inject additional claims from the access token into the authentication token via the --add-claims option. For example, a token from Keycloak provider might include the following claims.

"resource_access": {},
"name": "Rohith Jayawardene",
"preferred_username": "rohith.jayawardene",
"given_name": "Rohith",
"family_name": "Jayawardene",
"email": "gambol99@gmail.com"

In order to request you receive the given_name, family_name and name in the authentication header we would add --add-claims=given_name --add-claims=family_name etc. Or in the configuration file

add-claims:
- given_name
- family_name
- name

This would add the additional headers to the authenticated request along with standard ones.

X-Auth-Family-Name: Jayawardene
X-Auth-Given-Name: Rohith
X-Auth-Name: Rohith Jayawardene

- 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. The key length should either 16 or 32 bytes depending or whether you want AES-128 or AES-256.

- ClientID & Secret

Note, the client secret is optional and only required for setups where the oauth provider is using access_type = confidential; if the provider is 'public' simple add the client id. Alternatively, you might not need the proxy to perform the oauth authentication flow and instead simply verify the identity token (and potential role permissions), in which case, again just drop the client secret and use the client id and discovery-url.

- Claim Matching

The proxy supports adding a variable list of claim matches against the presented tokens for additional access control. So for example you can match the 'iss' or 'aud' to the token or custom attributes; note each of the matches are regex's. Examples, --match-claims 'aud=sso.' --claim iss=https://.' or via the configuration file. Note, each of matches are regex's

match-claims:
  aud: openvpn
  iss: https://keycloak.example.com/auth/realms/commons

- 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-page=PATH. The sign-in page will have a 'redirect' variable passed into the scope and holding 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>

- White-listed URL's

Depending on how the application url's are laid out, you might want protect the root / url but have exceptions on a list of paths, i.e. /health etc. Although you should probably fix this by fixing up the paths, you can add excepts to the protected resources. (Note: it's an array, so the order is important)

  resources:
  - url: /some_white_listed_url
    white-listed: true
  - url: /
    methods:
      - GET
    roles:
      - <CLIENT_APP_NAME>:<ROLE_NAME>
      - <CLIENT_APP_NAME>:<ROLE_NAME>

Or on the command line

  --resource "uri=/some_white_listed_url,white-listed=true"
  --resource "uri=/"  # requires authentication on the rest
  --resource "uri=/admin|roles=admin,superuser|methods=POST,DELETE

- Mutual TLS

The proxy support enforcing mutual TLS for the clients by simply adding the --tls-ca-certificate command line option or config file option. All clients connecting must present a certificate which was signed by the CA being used.

- Refresh Tokens

Assuming a request for an access token contains a refresh token and the --enable-refresh-token is true, the proxy will automatically refresh the access token for you. The tokens themselves are kept either as an encrypted (--encryption-key=KEY) cookie (cookie name: kc-state). or a store (still requires encryption key).

At present the only store supported areRedis and Boltdb. To enable a local boltdb store. --store-url boltdb:///PATH or relative path boltdb://PATH. For redis the option is redis://[USER:PASSWORD@]HOST:PORT. In both cases the refresh token is encrypted before placing into the store.

- Logout Endpoint

A /oauth/logout?redirect=url is provided as a helper to logout the users, aside from dropping a sessions cookies, we also attempt to revoke session access via revocation url (config revocation-url or --revocation-url) with the provider. For keycloak the url for this would be https://keycloak.example.com/auth/realms/REALM_NAME/protocol/openid-connect/logout, for google /oauth/revoke

- Cross Origin Resource Sharing (CORS)

You are permitted to add CORS following headers into the /oauth uri namespace

• Access-Control-Allow-Origin
• Access-Control-Allow-Methods
• Access-Control-Allow-Headers
• Access-Control-Expose-Headers
• Access-Control-Allow-Credentials
• Access-Control-Max-Age

Either from the config file:

cors:
  origins:
  - '*'
  methods:
  - GET
  - POST

or via the command line arguments

--cors-origins [--cors-origins option]                  a set of origins to add to the CORS access control (Access-Control-Allow-Origin)
--cors-methods [--cors-methods option]                  the method permitted in the access control (Access-Control-Allow-Methods)
--cors-headers [--cors-headers option]                  a set of headers to add to the CORS access control (Access-Control-Allow-Headers)
--cors-exposes-headers [--cors-exposes-headers option]  set the expose cors headers access control (Access-Control-Expose-Headers)

- Upsteam URL

You can control the upstream endpoint via the --upstream-url option. Both http and https is supported with TLS verification and keepalive support configured via the --skip-upstream-tls-verify / --upstream-keepalives option. Note, the proxy can also upstream via a unix socket, --upstream-url unix://path/to/the/file.sock

- Endpoints

• /oauth/authorize is authentication endpoint which will generate the openid redirect to the provider
• /oauth/callback is provider openid callback endpoint
• /oauth/expired is a helper endpoint to check if a access token has expired, 200 for ok and, 401 for no token and 401 for expired
• /oauth/health is the health checking endpoint for the proxy, you can also grab version from headers
• /oauth/login provides a relay endpoint to login via grant_type=password i.e. POST /oauth/login form values are username=USERNAME&password=PASSWORD
• /oauth/logout provides a convenient endpoint to log the user out, it will always attempt to perform a back channel logout of offline tokens
• /oauth/token is a helper endpoint which will display the current access token for you