Configure True SSO with SSSD on Ubuntu/Debian Desktops

To enable True SSO on an Ubuntu/Debian desktop, integrate the base virtual machine (VM) with an Active Directory (AD) domain using the SSSD solution. Then install the root Certificate Authority (CA) certificate to support trusted authentication before installing Horizon Agent.

Use the following procedure to enable True SSO with SSSD on an Ubuntu/Debian VM.

Some examples in the procedure use placeholder values to represent entities in your network configuration, such as the host name of your VM. Replace the placeholder values with information specific to your configuration, as described in the following table.

Prerequisites

• Verify that the VM is running one of the following distributions.

  • Ubuntu 22.04/20.04
  • Debian 12.x/11.x Note: True SSO with SSSD is not supported for Debian 10.x desktops. To configure True SSO on a Debian 10.x desktop, use Samba domain-join instead as described in Configure True SSO with Samba for Ubuntu/Debian Desktops.

• Configure True SSO for Workspace ONE Access and Horizon Connection Server.

• Get a root CA certificate and save it to /tmp/certificate.cer on the Ubuntu/Debian VM. See How to Export Root Certification Authority Certificate.

  If a subordinate CA is also an issuing authority, then get the entire chain of root and subordinate CA certificates and save it to /tmp/certificate.cer on the VM.

Procedure

1. On the base VM, verify the network connection to Active Directory.

   sudo realm discover mydomain.com
   

2. Install the required dependency packages.

   sudo apt-get install sssd-tools sssd libnss-sss libpam-sss adcli samba-common-bin krb5-user krb5-pkinit
   

3. Join the AD domain.

   sudo realm join --verbose mydomain.com -U admin-user
   

4. Install the root CA certificate or certificate chain.

   1. Locate the root CA certificate or certificate chain that you downloaded, and transfer it to a PEM file.

      sudo openssl x509 -inform der -in /tmp/certificate.cer -out /tmp/certificate.pem
      

   2. Copy the certificate to the /etc/sssd/pki/sssd_auth_ca_db.pem file.

      sudo cp /tmp/certificate.pem /etc/sssd/pki/sssd_auth_ca_db.pem
      

5. Modify the /etc/sssd/sssd.conf configuration file, as shown in the following example.

   [sssd]
   domains = mydomain.com
   config_file_version = 2
   services = nss, pam
    
   [domain/mydomain.com]
   ad_domain = mydomain.com
   krb5_realm = MYDOMAIN.COM
   realmd_tags = manages-system joined-with-adcli
   cache_credentials = True
   id_provider = ad
   krb5_store_password_if_offline = True
   default_shell = /bin/bash
   ldap_id_mapping = True
   use_fully_qualified_names = False #Use short name for user
   fallback_homedir = /home/%u@%d
   access_provider = ad
   ad_gpo_map_interactive            #For SSO, you can add this line for ad_gpo_map_interactive and set equal to a +gdm value. You must obtain from Omnissa Support the appropriate value for your specific Horizon version
   
   ad_gpo_access_control = permissive #Only add this line for Ubuntu 20.04 and Debian 12 to fix https://bugs.launchpad.net/ubuntu/+source/sssd/+bug/1934997
    
   [pam] #Add pam section for certificate login
   pam_cert_auth = True #Add this line to enable certificate login for system
   pam_p11_allowed_services        #To enable certificate logon for Horizon Agent, you can add this line for pam_p11_allowed_services and set equal to a +gdm value. You must obtain from Omnissa Support the appropriate value for your specific Horizon version
    
   [certmap/mydomain.com/truesso] #Add this section and following lines to set match and map rule for certificate user
   matchrule = <EKU>msScLogin
   maprule = (|(userPrincipal={subject_principal})(samAccountName={subject_principal.short_name}))
   domains = mydomain.com
   priority = 10
   

6. Change the access mode for the /etc/krb5.conf configuration file to make it editable.

   sudo chmod 644 /etc/krb5.conf
   

7. Modify the /etc/krb5.conf file, as shown in the following example.

   [realms]
    MYDOMAIN.COM = {
       kdc = kdcserver.mydomain.com
       admin_server = dnsserver.mydomain.com
       pkinit_anchors = DIR:/etc/sssd/pki
       pkinit_kdc_hostname = kdcserver.mydomain.com
       pkinit_eku_checking = kpServerAuth
    }
    
   [domain_realm]
       .mydomain.com = MYDOMAIN.COM
       mydomain.com = MYDOMAIN.COM
   

8. Install the Horizon Agent package, with True SSO enabled.

   sudo ./install_viewagent.sh -T yes
   

9. Modify the viewagent-custom.conf configuration file so that it includes the following line.

   NetbiosDomain = MYDOMAIN
   

10. Restart the VM and log back in.