FreedomTunnel

FLOSS Single Sign On One Time Password System

Short and sweet version

FreeIPA looks pretty compelling and will take care of a lot of the involved pieces (NTP/Ldap/Kerberos) in one shot.

https://docs.fedoraproject.org/en-US/Fedora/15/html/FreeIPA_Guide/index.html

Add in radius via

http://consultancy.edvoncken.net/index.php/HOWTO_Configure_Radius_with_an_IPA_Server

and

CoSign for web sso (found at http://forums.somethingawful.com/showthread.php?threadid=3459961)

and you've got everything for single sign on / single password.

Now just need to add OTP.

Introduction/Overview

I've wanted to do this for some time. Create a fully open source/free software based system for one time password authentication.

The idea is that I can login to a Windows/Mac/Linux system, enter a one time password (PIN number + 6 digit code), and be authenticated to everything I use that requires a password without further authentication prompts.

Desired Features of the system

• Fully open source (all client and server pieces)
• Runs in a highly available master/(multi)slave fashion in multiple data centers.
• Must be seamless (login process is just username + password. Everything else is handled behind the scenes)
• OTP generation client must support Android/Blackberry/Apple devices

User experience

• Login to local workstation. This is a standard username/password combination. No network connectivity is required for this to function. However, if the device is connected to network already, then login system will indicate this and accept username/enhanced password (PIN+random digits). So a maximum of two logins is all that is ever required for access to any resource I control.
• SSH to a server/network device or browse to a webapp I control and not have any login prompts.

Supported Authentication Clients

• WPA-Enterprise 802.11 users on Windows, Mac, Linux
• Workstation OS logins on Windows, Mac, Linux
• VPN users (IPSEC/OpenVPN)
• Web applications (Wordpress/MediaWiki/Status.net/Tattler/Drupal/Redmine and any other apps I use)

Project Execution phases

Centralized authentication

Setup everything on my network that takes a password (workstations/network gear/wpa/www apps etc) to talk to OpenLDAP/Kerberos/FreeRadius. This way I will have a centralized auth store with policy control etc. One password for everything. In the event I have an application that can't use SSO, I can still have a common password for it.

What do I have that is capable of talking to these back ends?

• All Linux boxes (use Kerberos/OpenLDAP for logins)

• All Windows boxes (use Kereros/OpenLDAP/FreeRadius for logins)

• Web apps (most support LDAP directly, some I use the kerberos module and pam auth)

• Cisco gear (FreeRadius)

• Nanostation2 based wireless access points running OpenWRT (wpa2 enterprise to FreeRadius backend)

Involved components

• LDAP (this is the backend to everything else)
• 802.1x system for wired/wireless clients (one needs to be on the network in order to access auth backend). This would be a white list of authorized mac addresses. Any network access would result in prompt for credentials
• Kerberos (this is used for workstation logins)
• FreeRadius (this is used by cisco gear and for wireless user authentication)
• Clients authenticating

All the below components run on a VPS with Centos5.5. Up in the cloud (at my $dayjob which is a very large IAAS provider).

LDAP

LDAP is the back end for everything else (freeradius/kerberos serves as authentication methods for clients, talking to LDAP as authorization system). So it is key to have a working LDAP installation before doing anything else.

Followed howto at http://www.linuxmail.info/openldap-setup-howto/

• yum install openldap-servers openldap-clients
• base.ldif

dn: dc=knownelement,dc=com
dc: knownelement
objectClass: domain

users.ldif

[root@kno ~]# cat users.ldif 
dn: ou=People,dc=knownelement,dc=com
ou: People
objectClass: organizationalUnit

dn: uid=charles,ou=People,dc=knownelement,dc=com
uid: charles
cn: Wyble Charles
displayName: Charles Wyble
givenName: Charles
sn: Wyble
objectClass: inetOrgPerson
userPassword: password
mail: charles@knownelement.com
[root@kno ~]# 

• ldapadd -x -D "cn=Manager,dc=knownelement,dc=com" -w secretstuff -f base.ldif
• ldapadd -x -D "cn=Manager,dc=knownelement,dc=com" -w secretstuff -f users.ldif

Kerberos

• http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-kerberos.html
• http://www.centos.org/docs/5/html/5.1/Deployment_Guide/s1-kerberos-clients.html

Clients

Web applications

• Tattler / Memex (drupal based applications)
• Thinkup
• Piwigo
• OpenDocMan
• Status.net
• Wordpress
• Redmine
• Mediawiki
• EyeOS
• Thunderbird

Network gear

• Cisco switches/routers

One howto for FreeRADIUS/LDAP and cisco gear is at http://jenniferhuber.blogspot.com/2010/07/using-open-source-radius-server-in-your.html

• OpenWRT wireless gear

Workstations

• Windows
• Linux
  • Debian
  • RedHat

Source material

Here are links to various howtos I referenced to put this wiki page together.

http://blog.harritronics.com/2011/06/primer-authentication-radius-kerberos.html#comment-form

http://techpubs.spinlocksolutions.com/dklar/kerberos.html

http://techpubs.spinlocksolutions.com/dklar/ldap.html

http://www.rjsystems.nl/en/2100-d6-openldap-provider.php#tree

http://www.linuxhomenetworking.com/wiki/index.php/Quick_HOWTO_:_Ch31_:_Centralized_Logins_Using_LDAP_and_RADIUS

http://www.eduroamus.org/node/45

http://serverfault.com/questions/206054/how-to-integrate-radius-with-kerberos << highly relevant

Copy/paste of relevant bits

Here's how you make freeradius check a user/password combo against a Kerberos server, and authorize against your LDAP backend---stick this in your radius.conf:

modules {

   krb5 {
           keytab = ${confdir}/radius.keytab
           service_principal = radius/radius.example.com
   }

   ldap {
           cache = no
           server = "ldap"
           identity = "uid=freeradius,ou=Accounts,dc=example,dc=com"
           password = secret
           basedn = "dc=com"
           filter = "(krbPrincipalName=%{User-Name})"
           base_filter = "(objectClass=radiusprofile)"

           tls {
                   start_tls = no
                   # tls_cacertfile        = /path/to/cacert.pem
                   # tls_cacertdir         = /path/to/ca/dir/
                   # tls_certfile          = /path/to/radius.crt
                   # tls_keyfile           = /path/to/radius.key
                   # tls_randfile          = /path/to/rnd
                   # tls_require_cert      = "demand"
           }

           default_profile = "uid=freeradius,ou=Accounts,dc=example,dc=com"
           profile_attribute = "radiusProfileDn"
           access_attr = "dialupAccess"

           dictionary_mapping = ${raddbdir}/ldap.attrmap

           ldap_connections_number = 5

           groupname_attribute = cn
           groupmembership_filter = "(|(&(objectClass=GroupOfNames)(member=%{Ldap-UserDn}))(&(objectClass=GroupOfUniqueNames)(uniquemember=%{Ldap-UserDn})))"
           #groupmembership_attribute = radiusGroupName
           timeout = 4
           timelimit = 3
           net_timeout = 1
           # compare_check_items = yes
           # do_xlat = yes
           # access_attr_used_for_allow = yes

           # set_auth_type = yes
   }

}

This assumes you've added the correct radius schema (ships with freeradius, IIRC) into your LDAP directory, and it should point you in the right direction---I don't do 802.1X, but I do use this config to handle other kerberos-via-radius access control scenarios, and it's been running in production for a while now. Obviously, users are logging in with their full kerberos principals (rather than just usernames).

Radius / krb integration http://wiki.freeradius.org/Rlm_krb5