SSO with SAML, Keycloak and Nextcloud

Question

I am trying to setup Keycloak as a IdP (Identity Provider) and Nextcloud as a service. I want to setup Keycloak as to present a SSO (single-sign-on) page.

I am running a Linux-Server with a Intel compatible CPU. What is the correct configuration?

• Keycloak will be running as https://kc.domain.com
• Nextcloud will be running as https://nc.domain.com

Answer 1

Prerequisite:

To use this answer you will need to replace domain.com with an actual domain you own. Also, replace [email protected] with your working e-mail address.

It is assumed you have docker and docker-compose installed and running.

Setup your services with Docker

In addition to keycloak and nextcloud I use:

• nginx as a reverse-proxy
• letsencyrpt to generate the SSL-certificates for the sub-domains.

I'm setting up all the needed services with docker and docker-compose. This is how the docker-compose.yml looks like this:

version: '2'

  nginx-proxy:
    image: jwilder/nginx-proxy
    restart: unless-stopped
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - "/etc/nginx/vhost.d"
      - "./proxy-default.conf:/etc/nginx/conf.d/my-proxy.default.conf:ro"
      - "/usr/share/nginx/html"
      - "/var/run/docker.sock:/tmp/docker.sock:ro"
      - "./le-cert:/etc/nginx/certs:ro"
    labels:
      com.github.jrcs.letsencrypt_nginx_proxy_companion.nginx_proxy: "true"

  letsencrypt-nginx-proxy-companion:
    image: jrcs/letsencrypt-nginx-proxy-companion
    restart: unless-stopped
    depends_on:
      - nginx-proxy
    container_name: le-proxy-companion
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock:ro"
      - "./le-cert:/etc/nginx/certs:rw"
    volumes_from:
      - nginx-proxy

  keycloak:
    image: jboss/keycloak
    links:
      - keycloak-postgres:postgres
    ports:
      - 8080:8080
    volumes:
      - ./keycloak:/opt/jboss/keycloak
    environment:
      - KEYCLOAK_USER=admin
      - KEYCLOAK_PASSWORD=admin
      - "PROXY_ADDRESS_FORWARDING=true"
      - VIRTUAL_PORT=8080
      - VIRTUAL_HOST=kc.domain.com
      - LETSENCRYPT_HOST=kc.domain.com
      - [email protected]

  keycloak-postgres:
    image: postgres
    environment:
      - POSTGRES_DB=keycloak
      - POSTGRES_USER=keycloak
      - POSTGRES_PASSWORD=keycloak
    
  nextcloud:
    image: hoellen/nextcloud
    environment:
      - UPLOAD_MAX_SIZE=10G
      - APC_SHM_SIZE=128M
      - OPCACHE_MEM_SIZE=128
      - CRON_PERIOD=15m
      - TZ=Europe/Berlin
      - DOMAIN=nc.domain.com
      - ADMIN_USER=admin
      - ADMIN_PASSWORD=admin
      - DB_TYPE=mysql
      - DB_NAME=nextcloud
      - DB_USER=nextcloud
      - DB_PASSWORD=nextcloud
      - DB_HOST=nc-db
    volumes:
      - ./nc/nc-data:/data
      - ./nc/nc-config:/config
      - ./nc/nc-apps:/apps2
      - ./nc/nc-themes:/nextcloud/themes
    environment:
      - VIRTUAL_HOST=nc.domain.com
      - LETSENCRYPT_HOST=nc.domain.com
      - [email protected]

  nc-db:
    image: mariadb
    volumes:
      - ./nc/nc-db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=nextcloud
      - MYSQL_PASSWORD=nextcloud
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud

I put my docker-files in a folder docker and within this folder a project-specific folder. Here keycloak. Create them with:

mkdir -p ~/docker/keycloak

Create the docker-compose.yml-File with your preferred editor in this folder. Start the services with:

cd ~/docker/keycloak
docker-compose up -d

Wait a moment to let the services download and start. Check if everything is running with:

docker-compose ps

If a service isn't running. Issue a second docker-compose up -d and check again.

Configure Keycloak, add a new Realm

Open a browser and go to https://kc.domain.com . Click on Administration Console. As specified in your docker-compose.yml, Username and Password is admin.

On the top-left of the page, you need to create a new Realm. Click Add. Enter my-realm as the name. Click Save.

Click on the Keys-tab. Look at the RSA-entry. We will need to copy the Certificate of that line. Click on Certificate and copy-paste the content to a text editor for later use.

Prepare a Private Key and Certificate for Nextcloud

Open a terminal and issue:

openssl req  -nodes -new -x509  -keyout private.key -out public.cert

This creates two files: private.key and public.cert which we will need later for the nextcloud service.

Configure Nextcloud

Open a browser and go to https://nc.domain.com . As specified in your docker-compose.yml, Username and Password is admin.

You need to activate the SSO & Saml Authenticate which is disabled by default.

Important From here on don't close your current browser window until the setup is tested and running. If you close the browser before everything works you probably not be able to change your settings in nextcloud anymore. In such a case you will need to stop the nextcloud- and nextcloud-db-container, delete their respective folders, recreate them and start all over again.

Click on the top-right gear-symbol and then on the + Apps-sign. On the left now see a Menu-bar with the entry Security. Click it. You now see all security-related apps. Click on the Activate button below the SSO & SAML authentication App.

Click on the top-right gear-symbol again and click on Admin. Click on SSO & SAML authentication.

Use the following values:

• Attribute to map UID to: username
• Enable "Use SAML auth for the Nextcloud desktop clients (requires user re-authentication)"
• Copy the content of public.cert into the 'X.509 Certificate'-field
• Copy the content of private.key into the 'Private key of Service Provider'-field.
• Identifier of the IdP: https://kc.domain.com/auth/realms/my-realm
• URL Target of the IdP where the SP will send the Authentication Request Message: https://kc.domain.com/auth/realms/my-realm/protocol/saml
• URL Location of IdP where the SP will send the SLO Request: https://kc.domain.com/auth/realms/my-realm/protocol/saml
• Public X.509 certificate of the IdP: Copy the certificate from Keycloak from the Keys-tab of my-realm. You will need to add '-----BEGIN CERTIFICATE-----' in front of the key and '-----END CERTIFICATE-----' to the end of it.
• In-Service Provider Data:
  • Attribute, displayname: username
  • Attribute, email address: email
• Security Settings, enable the following options:
  • Indicates whether the samlp:AuthnRequest messages sent by this SP will be signed. [Metadata of the SP will offer this info]
  • Indicates whether the samlp:logoutRequest messages sent by this SP will be signed.
  • Indicates whether the samlp:logoutResponse messages sent by this SP will be signed.
  • Indicates a requirement for the samlp:Response, samlp:LogoutRequest and samlp:LogoutResponse elements received by this SP to be signed.
  • Indicates a requirement for the saml:Assertion elements received by this SP to be signed. [Metadata of the SP will offer this info]
• Check there is a Metadata valid beside the Download metadata XML-Button
• Click the Download metadata XML-Button. This generates and sends an XML file. Save it for use in the next step.

Configure Keycloak, Client

Access the Administrator Console again. Click on Clients and on the top-right click on the Create-Button.

Next to Import, click the Select File-Button. Select the XML-File you've created on the last step in Nextcloud.

Change:

• Client SAML Endpoint: https://kc.domain.com/auth/realms/my-realm

and click Save.

You are presented with a new screen. Change the following fields:

• Name: Nextcloud
• Valid Redirect URIs: https://nc.domain.com/ *
• Click Save

On the Tab Mappers:

• Click Delete-Button on the preassigned role list (if it exists)
• Click Create
  • Name: username
  • Mapper Type: User Property
  • Property: username
  • SAML Attribute Name: username
  • SAML Attribute NameFormat: Basic
  • Click Save
• Click Create
  • Name: email
  • Mapper Type: User Property
  • Property: email
  • SAML Attribute Name: email
  • SAML Attribute NameFormat: Basic
  • Click Save
• Click Create
  • Name: Roles
  • Mapper Type: Role List
  • Role attribute name: Roles
  • Friendly Name: roles
  • SAML Attribute NameFormat: Basic
  • Single Role Attrubute: On
  • Click Save

Configure Keycloak, Add user

• On the left side, click on Users
• On the top-right, click Add users
• Set the following values:
  • Username: user
  • Email: [email protected]
  • Click Save
• On the tab Credentials:
  • New Password: user
  • Password Confirmation: user
  • Temporary: Off
  • Click Reset Password
• A Window pops up:
  • Click Change Password

Test run

Open a new browser window in incognito/private mode. Eg. for google-chrome press Ctrl-Shift-N, in Firefox press Ctrl-Shift-P. Keep the other browser window with the nextcloud setup page open. Else you might lock yourself out.

Access https://nc.domain.com with the incognito/private browser window. You are presented with the keycloak username/password page. Enter user as a name and password. You should be greeted with the nextcloud welcome screen.

Acknowledgement

• This guide wouldn't have been possible without the wonderful http://int128.hatenablog.com/entry/2018/01/16/194048 blog entry. I've read it with google-translator in English.
• Thanks goes also to RMM. His wiki entry allowed me to create correct keys for nextcloud and enable message-signing, thus improving this answer.