OpenID Connect with Dex

Dex is a lightweight OpenID Connect authentication provider written in Go, and is the default authentication mechanism shipped with Open OnDemand.

Installing OnDemand Dex package

First the OnDemand yum repos must be enabled, see Install Software From Package.

Install the ondemand-dex RPM:

sudo yum install ondemand-dex

Installing OnDemand Dex from source

Requirements:

• Go version 1.14.x with the go binary in PATH

• Git

• Make

Build and install the ondemand-dex binary:

GOPATH=$(go env GOPATH)
go get github.com/dexidp/dex
cd $GOPATH/src/github.com/dexidp/dex
make
sudo install -m 0755 bin/dex /usr/sbin/ondemand-dex

Add the ondemand-dex user and group:

sudo groupadd -r ondemand-dex
sudo useradd -r -d /var/lib/ondemand-dex -g ondemand-dex -s /sbin/nologin -c "OnDemand Dex"

Get ondemand-dex repo and install web files and systemd unit file

cd /tmp
git clone https://github.com/OSC/ondemand-dex
sudo mkdir /usr/share/ondemand-dex
sudo cp -R ondemand-dex/web /usr/share/ondemand-dex/web
sudo install -m 0644 ondemand-dex/examples/ondemand-dex.service /etc/systemd/system/ondemand-dex.service

Configuring OnDemand Dex

OnDemand Dex is configured by modifying the Open OnDemand Portal ood_portal.yml file /etc/ood/config/ood_portal.yml.

The default location for Dex configurations is /etc/ood/dex/config.yaml.

When changes are needed for OnDemand Dex run the following command:

sudo /opt/ood/ood-portal-generator/sbin/update_ood_portal
sudo systemctl restart ondemand-dex

Warning

If OnDemand is configured to use SSL and SSL certificates are not configured in Dex, the default behavior is for Dex to use copies of the OnDemand certificates for SSL. This means when the OnDemand certificates are updated it’s necessary to run update_ood_portal to make new copies of the certificates and restart ondemand-dex.

Managing the OnDemand Dex service

The service for OnDemand Dex is ondemand-dex:

sudo systemctl enable ondemand-dex.service
sudo systemctl start ondemand-dex.service

Dex Firewall

By default when using SSL, Dex will use port 5554 for the communication between OnDemand and Dex as well as login interactions with users accessing OnDemand. The port used for non-SSL is 5556. The port being used by Dex must be externally accessible.

Firewalld example:

$ sudo firewall-cmd --zone=public --add-port=5554/tcp --permanent
$ sudo firewall-cmd --reload

Iptables example:

$ sudo iptables -I INPUT -p tcp -m tcp --dport 5554 -j ACCEPT
$ sudo iptables-save > /etc/sysconfig/iptables

Configuring OnDemand Dex behind Apache reverse proxy

The OnDemand Dex service can be proxied behind the Apache web service using a reverse proxy. This would mean port 5554 or 5556 would not need to be opened.

Enabling the OnDemand Dex reverse proxy logic will force Dex to listen only on localhost and only via HTTP.

Example of configuration change to put Dex behind the Apache reverse proxy

dex_uri: /dex

Configuring OnDemand Dex for LDAP

Requirements:

• an LDAP server preferably with SSL support (openldap.my_center.edu:636)

The following is an example configuration using OpenLDAP.

# /etc/ood/config/ood_portal.yml
---

# ...
dex:
  connectors:
    - type: ldap
      id: ldap
      name: LDAP
      config:
        host: openldap.my_center.edu:636
        insecureSkipVerify: false
        bindDN: cn=admin,dc=example,dc=org
        bindPW: admin
        userSearch:
          baseDN: ou=People,dc=example,dc=org
          filter: "(objectClass=posixAccount)"
          username: uid
          idAttr: uid
          emailAttr: mail
          nameAttr: gecos
          preferredUsernameAttr: uid
        groupSearch:
          baseDN: ou=Groups,dc=example,dc=org
          filter: "(objectClass=posixGroup)"
          userMatchers:
            - userAttr: DN
              groupAttr: member
          nameAttr: cn

Note

For documentation on Dex LDAP configuration please see the Dex LDAP docs

Note

If you supply a bindPW in this file it’s recommended to change the file permissions on /etc/ood/config/ood_portal.yml to be 0600 make the file only readable by root:

sudo chown root:root /etc/ood/config/ood_portal.yml
sudo chmod 0600 /etc/ood/config/ood_portal.yml

Customizing OnDemand Dex

The theme for Dex can be customized to be site-specific, see Customize Dex Theme.

OnDemand Dex configuration reference

The OnDemand Dex configuration works by attempting to expose all Dex configuration options as keys nested under the dex key in /etc/ood/config/ood_portal.yml.

The following reference is for /etc/ood/config/ood_portal.yml values set under the dex key.

ssl (Boolean, null)

Boolean to set if SSL is used, is true if OnDemand is configured for SSL, otherwise this defaults to false. This value is used to determine which listen ports to use for Dex as well as OIDC configurations for OnDemand

http_port (String, Integer)

The HTTP port used by Dex, default is 5556. Used to define web -> http in the Dex configuration as well as OIDC configurations

https_port (String, Integer)

The HTTPS port used by Dex, default is 5554. This value is only set if SSL is enabled. Used to define web -> https in the Dex configuration as well as OIDC configurations

tls_cert (String, null)

The path to TLS cert used by Dex. The default is to use the SSL certificate for OnDemand if OnDemand is configured with SSL. Used to define web -> tlsCert in the Dex configuration. If using the OnDemand certificate, a copy is made to /etc/ood/dex. The ondemand-dex user must be able to read this file if configured.

tls_key (String, null)

The path to TLS key used by Dex. The default is to use the SSL key for OnDemand if OnDemand is configured with SSL. Used to define web -> tlsKey in the Dex configuration. If using the OnDemand key, a copy is made to /etc/ood/dex. The ondemand-dex user must be able to read this file if configured.

storage_file (String)

The path to the Dex SQLite storage file. Defaults to /etc/ood/dex/dex.db. Used to define storage -> config -> file in the Dex configuration.

client_id (String)

The client ID used for the OnDemand OIDC client. The default is to use the servername for OnDemand, and if that is not defined the host’s FQDN is used. Sets staticClients[0] -> id in the Dex configuration as well as OnDemand OIDC configurations.

client_secret (String)

The client secret used for the OnDemand OIDC client. The default is a randomly generated secret stored in /etc/ood/dex/ondemand.secret. The value for this configuration can either be the secret string or path to file storing the secret. If using a file, the ondemand-dex user must be able to read the file. Sets staticClients[0] -> secret in the Dex configuration as well as OnDemand OIDC configurations.

client_redirect_uris (Array<String>)

Additional OIDC client URIs to authorize for the OnDemand client. The values provided for this are merged with the default redirect URI generated for OnDemand. Sets staticClients[0] -> redirectURIs in the Dex configuration as well as OnDemand OIDC configurations.

client_name (String)

The default OIDC client name for Dex. Defaults to OnDemand. Sets staticClients[0] -> name in the Dex configuration.

connectors (Array<Hash>)

This defines the external connectors used to authenticate users with Dex. If this value is not provided the default behavior is to set a static password of password for user ood@localhost. This value is passed directly to the Dex configuration for connectors. For an example of LDAP configuration see Configuring OnDemand Dex for LDAP.

frontend (Hash)

This defines various changes for the themes and frontend look of Dex. The value provided is passed directly to the Dex configuration for frontend. If dir key is not set the default of /usr/share/ondemand-dex/web is used. If theme key is not set the default of ondemand is used.

Default

frontend:
  dir: "/usr/share/ondemand-dex/web"
  theme: "ondemand"

grpc (Hash)

The configuration for Dex’s gRPC API. Value is passed directly to the Dex configuration

Example:

grpc:
  addr: "127.0.0.1:5557"
  tlsCert: "/etc/ood/dex/grpc-server.crt"
  tlsKey: "/etc/ood/dex/grpc-server.key"
  tlsClientCA: "/etc/ood/dex/grpc-ca.crt"

expiry (Hash)

The configuration for Dex’s expirations. Value is passed directly to the Dex configuration

Example:

expiry:
  signingKeys: "6h"
  idTokens: "24h"