Rasp

What is this?

The Shibboleth Service Provider is a SAML-based single sign on (SSO) client widely deployed in academic organisations. It's used to provide access control to resources and service for millions of staff and students around the world. The Shibboleth SP integrates very well with Apache HTTPd, providing sophisticated authentication and access control for web pages and web applications.

Rasp is a minimalist, Debian-based Docker image that contains the Apache web server and Shibboleth SP. It is maintained by Digital Identity Ltd and commercial support is available from Mimoto Ltd. Rasp is intended to be a solid foundation for other containers but can also be used directly by mounting volumes for configuration directories.

This image is not a ready-to-use, stand-alone SP service - it's meant to be configured and then used in conjunction with other services, or extended with additional software such as PHP or web applications. Rasp aims to be a good Docker image with careful use of layers, correct signal handling, logging to STDOUT by default and a healthcheck.

Why use this?

• Relatively compact (it's still quite large at 70Mb to download but we've tried our best and it's smaller than many others)
• Apache and Shibd processed are properly managed by Runit
• Logging is directed to STDOUT by default
• Apache and Shibboleth SP configuration files are easily customised
• Follows Docker best-practice
• Experimental: also includes mod-auth-openidc and mod-auth-cas (enabled using ENV)

Any reasons not to use this?

• It is not ready-to-use, and there is no UI or simplified configuration: you need to understand how to configure both Apache HTTPd and Shibboleth SP software.
• It's got no warranty or support by default, but you probably weren't expecting any.
• TLS is up to you: either mount keys and configuration, or use a reverse proxy/load balancer
• Docker should not be used in production unless you have a reliable process for regularly updating images and replacing containers.

Configuring and running Rasp

Releases

Images are available from Dockerhub and Github:

• https://hub.docker.com/repository/docker/digitalidentity/rasp
• https://github.com/orgs/Digital-Identity-Labs/packages/container/package/rasp

Getting the image

• docker pull digitalidentity/rasp:latest to get the latest default version from DockerHub
• docker pull ghcr.io/digital-identity-labs/rasp:latest" to get the latest version from Github

Configuring Apache and the Shibboleth SP

Run the unconfigured default SP in the foreground, with a http port available:

docker run -it digitalidentity/rasp

Copy the current configuration from the running container:

containerid=$(docker ps | grep rasp | awk '{print $1}')

mkdir etcfs

docker cp $containerid:/etc/apache2 ./etcfs/apache2
docker cp $containerid:/etc/shibboleth ./etcfs/shibboleth

docker stop $containerid

Adjust these files to suit your use-case - see the Shibboleth IdP documentation for lots more information.

As you're probably copying these files over the top of existing files, you don't need to keep copies of files you aren't changing.

Running Rasp with your configuration

Then you can either build an image that contains your configuration, like this:

FROM ghcr.io/digital-identity-labs/rasp:latest
# (Don't use latest in production)

LABEL description="An example SP image based on Rasp" \
      version="0.0.1" \
      maintainer="example@example.com"

ENV SP_HOST="sp.my-example.org"
ENV SP_URL="https://$SP_HOST"
ENV SP_ID="$SP_URL/shibboleth"

## Copy your configuration files over into the image
COPY etcfs/apache2 /etc/apache2
COPY etcfs/shibboleth /etc/shibboleth

or run the Rasp image with mounted directories or files:

docker run -it -p 80:80 -v /home/bjensen/myshib/etcfs/apache2:/etc/apache2 -v /home/bjensen/myshib/etcfs/shibboleth:/etc/shibboleth digitalidentity/rasp

Using with Docker Compose

Running a relatively bare Rasp container on its own is only useful for some basic dev or testing work. It's far more useful when used with other Docker containers.

For example, a docker-compose.yml file like this can provide a basic SP service, with TLS:

version: '3'
services:
  frontend:
    image: traefik:latest
    command:
      - --api.insecure=false
      - --api.dashboard=false
      - --api.debug=false
      - --log.level=INFO
      - --providers.docker=true
      - --providers.docker.swarmMode=false
      - --providers.docker.exposedbydefault=false
      - --entrypoints.http.address=:80
      - --entrypoints.https.address=:443
      - --certificatesresolvers.letsencrypt.acme.httpchallenge=true
      - --certificatesresolvers.letsencrypt.acme.httpchallenge.entrypoint=http
      - --certificatesresolvers.letsencrypt.acme.email=pete@example.com
      - --certificatesresolvers.letsencrypt.acme.storage=/letsencrypt/acme.json
    ports:
      - "443:443"
      - "80:80"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - letsencrypt:/letsencrypt
    depends_on:
      - sp
  sp:
    image: rasp:latest
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.sp.entrypoints=https"
      - "traefik.http.routers.sp.rule=Host(`testsp.example.com`)"
      - "traefik.http.routers.sp.tls=true"
      - "traefik.http.routers.sp.tls.certresolver=letsencrypt"
      - "traefik.http.routers.sp.tls.domains[0].main=testsp.example.com"
      - "traefik.http.services.sp.loadbalancer.server.port=443"
      - "traefik.port=80"
      - "traefik.default.protocol=http"
      - "traefik.http.middlewares.tweak_sp.headers.customrequestheaders.X-Forwarded-Host=testsp.example.com"
      - "traefik.http.middlewares.tweak_sp.headers.customrequestheaders.X-Forwarded-Proto=https"
      - "traefik.http.routers.sp.middlewares=tweak_sp@docker"

volumes:
  letsencrypt:

networks:
  web:
    external: true

When building an image based on Rasp

Possibly useful things to know:

• The Rasp repository contains some tests - you can copy these into your new project, and extend them.
• Certificate rebuilds will happen when the new image is built, to make sure you are not using any inherited keys. You can generate your own using /etc/rasp/keygen.sh or manually with /usr/sbin/shib-keygen but please try to keep them off the image - mount them from disk if possible.
• APACHE_EXTRA_MODS can be used to enable additional modules that are present but not loaded by default. Separate each module name with a space, for example:
  APACHE_EXTRA_MODS="auth_openidc authnz_ldap auth_cas"
• /etc/scripts contains scripts that are run when the container starts, but before Apache is launched.

When using Rasp's Dockerfile to build your own images

• SP_HOST: the host/domain name of the primary SP/website
• SP_URL: the full root URL of the primary SP/website
• SP_ID: the entity ID of the primary SP
• APACHE_EXTRA_MODS: is a list of extra modules to enable at runtime

Other Information

Related Projects from Digital Identity

• Ishigaki - An IdP base image
• MDQT - A tool for handling SAML metadata and MDQ services

Why is this called "Rasp"?

This project started life as Rails Apache SP (RASP) but the Ruby on Rails parts have been removed (we're adding Rails in a derived image now, and keeping Rasp as simple as possible)

Thanks

• We're just packaging huge amounts of work by The Shibboleth Consortium, Debian and the wider Shibboleth community. If your organisation depends on Shibboleth please consider supporting them with a donation.

Contributing

You can request new features by creating an issue, or submit a pull request with your contribution.

The Rasp repo contains tests that you can use in your own projects. We're extra grateful for any contributions that include tests.

If you have a support contract with Mimoto, please contact Mimoto for assistance, rather than use Github.

License

Copyright (c) 2017,2022 Digital Identity Ltd, UK

Licensed under the MIT License