thomseddon/traefik-forward-auth

•Updated over 5 years ago

Minimal forward authentication that provides Google oauth login + auth for traefik reverse proxy

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thomseddon/traefik-forward-auth repository overview

⁠Traefik Forward Auth

A minimal forward authentication service that provides OAuth/SSO login and authentication for the traefik⁠ reverse proxy/load balancer.

⁠Why?

Seamlessly overlays any http service with a single endpoint (see: url-path in Configuration⁠)
Supports multiple providers including Google and OpenID Connect (supported by Azure, Github, Salesforce etc.)
Supports multiple domains/subdomains by dynamically generating redirect_uri's
Allows authentication to be selectively applied/bypassed based on request parameters (see rules in Configuration⁠)
Supports use of centralised authentication host/redirect_uri (see auth-host in Configuration⁠)
Allows authentication to persist across multiple domains (see Cookie Domains⁠)
Supports extended authentication beyond Google token lifetime (see: lifetime in Configuration⁠)

⁠Contents

⁠Releases

We recommend using the 2 tag on docker hub (thomseddon/traefik-forward-auth:2).

You can also use the latest incremental releases found on docker hub⁠ and github⁠.

ARM releases are also available on docker hub, just append -arm or -arm64 to your desired released (e.g. 2-arm or 2.1-arm64).

We also build binary files for usage without docker starting with releases after 2.2.0 You can find these as assets of the specific GitHub release.

⁠Upgrade Guide

v2 was released in June 2019, whilst this is fully backwards compatible, a number of configuration options were modified, please see the upgrade guide⁠ to prevent warnings on startup and ensure you are using the current configuration.

⁠Usage

⁠Simple:

See below for instructions on how to setup your Provider Setup⁠.

docker-compose.yml:

version: '3'

services:
  traefik:
    image: traefik:v2.2
    command: --providers.docker
    ports:
      - "8085:80"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock

  traefik-forward-auth:
    image: thomseddon/traefik-forward-auth:2
    environment:
      - PROVIDERS_GOOGLE_CLIENT_ID=your-client-id
      - PROVIDERS_GOOGLE_CLIENT_SECRET=your-client-secret
      - SECRET=something-random
      - INSECURE_COOKIE=true # Example assumes no https, do not use in production
    labels:
      - "traefik.http.middlewares.traefik-forward-auth.forwardauth.address=http://traefik-forward-auth:4181"
      - "traefik.http.middlewares.traefik-forward-auth.forwardauth.authResponseHeaders=X-Forwarded-User"
      - "traefik.http.services.traefik-forward-auth.loadbalancer.server.port=4181"

  whoami:
    image: containous/whoami
    labels:
      - "traefik.http.routers.whoami.rule=Host(`whoami.mycompany.com`)"
      - "traefik.http.routers.whoami.middlewares=traefik-forward-auth"

⁠Advanced:

Please see the examples directory for a more complete docker-compose.yml⁠ or kubernetes/simple-separate-pod⁠.

Also in the examples directory is docker-compose-auth-host.yml⁠ and kubernetes/advanced-separate-pod⁠ which shows how to configure a central auth host, along with some other options.

⁠Provider Setup

Below are some general notes on provider setup, specific instructions and examples for a number of providers can be found on the Provider Setup⁠ wiki page.

⁠Google

Head to https://console.developers.google.com⁠ and make sure you've switched to the correct email account.

Create a new project then search for and select "Credentials" in the search bar. Fill out the "OAuth Consent Screen" tab.

Click "Create Credentials" > "OAuth client ID". Select "Web Application", fill in the name of your app, skip "Authorized JavaScript origins" and fill "Authorized redirect URIs" with all the domains you will allow authentication from, appended with the url-path (e.g. https://app.test.com/_oauth⁠)

You must set the providers.google.client-id and providers.google.client-secret config options.

⁠OpenID Connect

Any provider that supports OpenID Connect 1.0 can be configured via the OIDC config options below.

You must set the providers.oidc.issuer-url, providers.oidc.client-id and providers.oidc.client-secret config options.

Please see the Provider Setup⁠ wiki page for examples.

⁠Generic OAuth2

For providers that don't support OpenID Connect, we also have the Generic OAuth2 provider where you can statically configure the OAuth2 and "user" endpoints.

You must set:

providers.generic-oauth.auth-url - URL the client should be sent to authenticate the authenticate
providers.generic-oauth.token-url - URL the service should call to exchange an auth code for an access token
providers.generic-oauth.user-url - URL used to retrieve user info (service makes a GET request)
providers.generic-oauth.client-id - Client ID
providers.generic-oauth.client-secret - Client Secret

You can also set:

providers.generic-oauth.scope- Any scopes that should be included in the request (default: profile, email)
providers.generic-oauth.token-style - How token is presented when querying the User URL. Can be header or query, defaults to header. With header the token is provided in an Authorization header, with query the token is provided in the access_token query string value.

Please see the Provider Setup⁠ wiki page for examples.

⁠Configuration

⁠Overview

The following configuration options are supported:

Usage:
  traefik-forward-auth [OPTIONS]

Application Options:
  --log-level=[trace|debug|info|warn|error|fatal|panic] Log level (default: warn) [$LOG_LEVEL]
  --log-format=[text|json|pretty]                       Log format (default: text) [$LOG_FORMAT]
  --auth-host=                                          Single host to use when returning from 3rd party auth [$AUTH_HOST]
  --config=                                             Path to config file [$CONFIG]
  --cookie-domain=                                      Domain to set auth cookie on, can be set multiple times [$COOKIE_DOMAIN]
  --insecure-cookie                                     Use insecure cookies [$INSECURE_COOKIE]
  --cookie-name=                                        Cookie Name (default: _forward_auth) [$COOKIE_NAME]
  --csrf-cookie-name=                                   CSRF Cookie Name (default: _forward_auth_csrf) [$CSRF_COOKIE_NAME]
  --default-action=[auth|allow]                         Default action (default: auth) [$DEFAULT_ACTION]
  --default-provider=[google|oidc|generic-oauth]        Default provider (default: google) [$DEFAULT_PROVIDER]
  --domain=                                             Only allow given email domains, can be set multiple times [$DOMAIN]
  --lifetime=                                           Lifetime in seconds (default: 43200) [$LIFETIME]
  --logout-redirect=                                    URL to redirect to following logout [$LOGOUT_REDIRECT]
  --url-path=                                           Callback URL Path (default: /_oauth) [$URL_PATH]
  --secret=                                             Secret used for signing (required) [$SECRET]
  --whitelist=                                          Only allow given email addresses, can be set multiple times [$WHITELIST]
  --port=                                               Port to listen on (default: 4181) [$PORT]
  --rule.<name>.<param>=                                Rule definitions, param can be: "action", "rule" or "provider"

Google Provider:
  --providers.google.client-id=                         Client ID [$PROVIDERS_GOOGLE_CLIENT_ID]
  --providers.google.client-secret=                     Client Secret [$PROVIDERS_GOOGLE_CLIENT_SECRET]
  --providers.google.prompt=                            Space separated list of OpenID prompt options [$PROVIDERS_GOOGLE_PROMPT]

OIDC Provider:
  --providers.oidc.issuer-url=                          Issuer URL [$PROVIDERS_OIDC_ISSUER_URL]
  --providers.oidc.client-id=                           Client ID [$PROVIDERS_OIDC_CLIENT_ID]
  --providers.oidc.client-secret=                       Client Secret [$PROVIDERS_OIDC_CLIENT_SECRET]
  --providers.oidc.resource=                            Optional resource indicator [$PROVIDERS_OIDC_RESOURCE]

Generic OAuth2 Provider:
  --providers.generic-oauth.auth-url=                   Auth/Login URL [$PROVIDERS_GENERIC_OAUTH_AUTH_URL]
  --providers.generic-oauth.token-url=                  Token URL [$PROVIDERS_GENERIC_OAUTH_TOKEN_URL]
  --providers.generic-oauth.user-url=                   URL used to retrieve user info [$PROVIDERS_GENERIC_OAUTH_USER_URL]
  --providers.generic-oauth.client-id=                  Client ID [$PROVIDERS_GENERIC_OAUTH_CLIENT_ID]
  --providers.generic-oauth.client-secret=              Client Secret [$PROVIDERS_GENERIC_OAUTH_CLIENT_SECRET]
  --providers.generic-oauth.scope=                      Scopes (default: profile, email) [$PROVIDERS_GENERIC_OAUTH_SCOPE]
  --providers.generic-oauth.token-style=[header|query]  How token is presented when querying the User URL (default: header)
                                                        [$PROVIDERS_GENERIC_OAUTH_TOKEN_STYLE]
  --providers.generic-oauth.resource=                   Optional resource indicator [$PROVIDERS_GENERIC_OAUTH_RESOURCE]

Help Options:
  -h, --help                                            Show this help message

All options can be supplied in any of the following ways, in the following precedence (first is highest precedence):

Command Arguments/Flags - As shown above
Environment Variables - As shown in square brackets above
File
1. Use INI format (e.g. url-path = _oauthpath)
2. Specify the file location via the --config flag or $CONFIG environment variable
3. Can be specified multiple times, each file will be read in the order they are passed

⁠Option Details

auth-host

When set, when a user returns from authentication with a 3rd party provider they will always be forwarded to this host. By using one central host, this means you only need to add this auth-host as a valid redirect uri to your 3rd party provider.

The host should be specified without protocol or path, for example:
```
--auth-host="auth.example.com"
```
For more details, please also read the Auth Host Mode⁠, operation mode in the concepts section.

Please Note - this should be considered advanced usage, if you are having problems please try disabling this option and then re-read the Auth Host Mode⁠ section.
config

Used to specify the path to a configuration file, can be set multiple times, each file will be read in the order they are passed. Options should be set in an INI format, for example:
```
url-path = _oauthpath
```
cookie-domain

When set, if a user successfully completes authentication, then if the host of the original request requiring authentication is a subdomain of a given cookie domain, then the authentication cookie will be set for the higher level cookie domain. This means that a cookie can allow access to multiple subdomains without re-authentication. Can be specificed multiple times.

For example:
```
--cookie-domain="example.com"  --cookie-domain="test.org"
```
For example, if the cookie domain test.com has been set, and a request comes in on app1.test.com, following authentication the auth cookie will be set for the whole test.com domain. As such, if another request is forwarded for authentication from app2.test.com, the original cookie will be sent and so the request will be allowed without further authentication.

Beware however, if using cookie domains whilst running multiple instances of traefik/traefik-forward-auth for the same domain, the cookies will clash. You can fix this by using a different cookie-name in each host/cluster or by using the same cookie-secret in both instances.
insecure-cookie

If you are not using HTTPS between the client and traefik, you will need to pass the insecure-cookie option which will mean the Secure attribute on the cookie will not be set.
cookie-name

Set the name of the cookie set following successful authentication.

Default: _forward_auth
csrf-cookie-name

Set the name of the temporary CSRF cookie set during authentication.

Default: _forward_auth_csrf
default-action

Specifies the behavior when a request does not match any rules⁠. Valid options are auth or allow.

Default: auth (i.e. all requests require authentication)
default-provider

Set the default provider to use for authentication, this can be overridden within rules⁠. Valid options are currently google or oidc.

Default: google
domain

When set, only users matching a given domain will be permitted to access.

For example, setting --domain=example.com --domain=test.org would mean that only users from example.com or test.org will be permitted. So [email protected]⁠ would be allowed but [email protected]⁠ would not.

For more details, please also read User Restriction⁠ in the concepts section.
lifetime

How long a successful authentication session should last, in seconds.

Default: 43200 (12 hours)
logout-redirect

When set, users will be redirected to this URL following logout.
match-whitelist-or-domain

When enabled, users will be permitted if they match either the whitelist or domain parameters.

This will be enabled by default in v3, but is disabled by default in v2 to maintain backwards compatibility.

Default: false

For more details, please also read User Restriction⁠ in the concepts section.
url-path

Customise the path that this service uses to handle the callback following authentication.

Default: /_oauth

Please note that when using the default Overlay Mode⁠ requests to this exact path will be intercepted by this service and not forwarded to your application. Use this option (or Auth Host Mode⁠) if the default /_oauth path will collide with an existing route in your application.
secret

Used to sign cookies authentication, should be a random (e.g. openssl rand -hex 16)
whitelist

When set, only specified users will be permitted.

For example, setting [email protected] [email protected] would mean that only those two exact users will be permitted. So [email protected]⁠ would be allowed but [email protected]⁠ would not.

For more details, please also read User Restriction⁠ in the concepts section.
rule

Specify selective authentication rules. Rules are specified in the following format: rule.<name>.<param>=<value>
- <name> can be any string and is only used to group rules together
- <param> can be:
  - action - same usage as default-action⁠, supported values:
    - auth (default)
    - allow
  - domains - optional, same usage as domain⁠
  - provider - same usage as default-provider⁠, supported values:
    - google
    - oidc
  - rule - a rule to match a request, this uses traefik's v2 rule parser for which you can find the documentation here: https://docs.traefik.io/v2.0/routing/routers/#rule⁠, supported values are summarised here:
    - Headers(`key`, `value`)
    - HeadersRegexp(`key`, `regexp`)
    - Host(`example.com`, ...)
    - HostRegexp(`example.com`, `{subdomain:[a-z]+}.example.com`, ...)
    - Method(methods, ...)
    - Path(`path`, `/articles/{category}/{id:[0-9]+}`, ...)
    - PathPrefix(`/products/`, `/articles/{category}/{id:[0-9]+}`)
    - Query(`foo=bar`, `bar=baz`)
  - whitelist - optional, same usage as whitelist`](#whitelist)
For example:
```
# Allow requests that being with `/api/public` and contain the `Content-Type` header with a value of `application/json`
rule.1.action = allow
rule.1.rule = PathPrefix(`/api/public`) && Headers(`Content-Type`, `application/json`)

# Allow requests that have the exact path `/public`
rule.two.action = allow
rule.two.rule = Path(`/public`)

# Use OpenID Connect provider (must be configured) for requests that begin with `/github`
rule.oidc.action = auth
rule.oidc.provider = oidc
rule.oidc.rule = PathPrefix(`/github`)

# Allow [email protected] to `/janes-eyes-only`
rule.two.action = allow
rule.two.rule = Path(`/janes-eyes-only`)
rule.two.whitelist = [email protected]
```
Note: It is possible to break your redirect flow with rules, please be careful not to create an allow rule that matches your redirect_uri unless you know what you're doing. This limitation is being tracked in in #101 and the behaviour will change in future releases.

⁠Concepts

⁠User Restriction

You can restrict who can login with the following parameters:

domain - Use this to limit logins to a specific domain, e.g. test.com only
whitelist - Use this to only allow specific users to login e.g. [email protected]⁠ only

Note, if you pass both whitelist and domain, then the default behaviour is for only whitelist to be used and domain will be effectively ignored. You can allow users matching either whitelist or domain by passing the match-whitelist-or-domain parameter (this will be the default behaviour in v3). If you set domains or whitelist on a rule, the global configuration is ignored.

⁠Forwarded Headers

The authenticated user is set in the X-Forwarded-User header, to pass this on add this to the authResponseHeaders config option in traefik, as shown below in the Applying Authentication⁠ section.

⁠Applying Authentication

Authentication can be applied in a variety of ways, either globally across all requests, or selectively to specific containers/ingresses.

⁠Global Authentication

This can be achieved by enabling forward authentication for an entire entrypoint, for example, with http only:

--entryPoints.http.address=:80
--entrypoints.http.http.middlewares=traefik-forward-auth # "default-traefik-forward-auth" on kubernetes

Or https:

--entryPoints.http.address=:80
--entryPoints.http.http.redirections.entryPoint.to=https
--entryPoints.http.http.redirections.entryPoint.scheme=https
--entryPoints.https.address=:443
--entrypoints.https.http.middlewares=traefik-forward-auth # "default-traefik-forward-auth" on kubernetes

Note: Traefik prepends the namespace to the name of middleware defined via a kubernetes resource. This is handled automatically when referencing the middleware from another resource in the same namespace (so the namespace does not need to be prepended when referenced). However the full name, including the namespace, must be used when referenced from static configuration (e.g. command arguments or config file), hence you must prepend the namespace to your traefik-forward-auth middleware reference, as shown in the comments above (e.g. default-traefik-forward-auth if your middleware is named traefik-forward-auth and is defined in the default namespace).

⁠Selective Ingress Authentication in Kubernetes

If you choose not to enable forward authentication for a specific entrypoint, you can apply the middleware to selected ingressroutes:

apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: whoami
  labels:
    app: whoami
spec:
  entryPoints:
    - http
  routes:
  - match: Host(`whoami.example.com`)
    kind: Rule
    services:
      - name: whoami
        port: 80
    middlewares:
      - name: traefik-forward-auth

See the examples directory for more examples.

⁠Selective Container Authentication in Swarm

You can apply labels to selected containers:

whoami:
  image: containous/whoami
  labels:
    - "traefik.http.routers.whoami.rule=Host(`whoami.example.com`)"
    - "traefik.http.routers.whoami.middlewares=traefik-forward-auth"

See the examples directory for more examples.

⁠Rules Based Authentication

You can also leverage the rules config to selectively apply authentication via traefik-forward-auth. For example if you enabled global authentication by enabling forward authentication for an entire entrypoint, you can still exclude some patterns from requiring authentication:

# Allow requests to 'dash.example.com'
rule.1.action = allow
rule.1.rule = Host(`dash.example.com`)

# Allow requests to `app.example.com/public`
rule.two.action = allow
rule.two.rule = Host(`app.example.com`) && Path(`/public`)

⁠Operation Modes

⁠Overlay Mode

Overlay is the default operation mode, in this mode the authorisation endpoint is overlaid onto any domain. By default the /_oauth path is used, this can be customised using the url-path option.

The user flow will be:

Request to www.myapp.com/home
User redirected to Google login
After Google login, user is redirected to www.myapp.com/_oauth
Token, user and CSRF cookie is validated (this request in intercepted and is never passed to your application)
User is redirected to www.myapp.com/home
Request is allowed

As the hostname in the redirect_uri is dynamically generated based on the original request, every hostname must be permitted in the Google OAuth console (e.g. www.myappp.com would need to be added in the above example)

⁠Auth Host Mode

This is an optional mode of operation that is useful when dealing with a large number of subdomains, it is activated by using the auth-host config option (see this example docker-compose.yml⁠ or this kubernetes example⁠).

For example, if you have a few applications: app1.test.com, app2.test.com, appN.test.com, adding every domain to Google's console can become laborious. To utilise an auth host, permit domain level cookies by setting the cookie domain to test.com then set the auth-host to: auth.test.com.

The user flow will then be:

Request to app10.test.com/home/page
User redirected to Google login
After Google login, user is redirected to auth.test.com/_oauth
Token, user and CSRF cookie is validated, auth cookie is set to `test.com

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