SSSD_KRB5_LOCALAUTH_(8)

NAME
sssd_krb5_localauth_plugin - Kerberos local authorization plugin

DESCRIPTION

The Kerberos local authorization plugin sssd_krb5_localauth_plugin is used by libkrb5 to either find the local name for a given Kerberos principal or to check if a given local name and a given Kerberos principal relate to each other.

SSSD handles the local names for users from a remote source and can read the Kerberos user principal name from the remote source as well. With this information SSSD can easily handle the mappings mentioned above even if the local name and the Kerberos principal differ considerably.

Additionally with the information read from the remote source SSSD can help to prevent unexpected or unwanted mappings in case the user part of the Kerberos principal accidentally corresponds to a local name of a different user. By default libkrb5 might just strip the realm part of the Kerberos principal to get the local name which would lead to wrong mappings in this case.

CONFIGURATION

The Kerberos local authorization plugin must be enabled explicitly in the Kerberos configuration, see krb5.conf(5). SSSD will create a config snippet with the content like e.g.

    [plugins]
     localauth = {
      disable = an2ln
      module = sssd:/usr/lib64/sssd/modules/sssd_krb5_localauth_plugin.so
     }

automatically in the SSSD's public Kerberos configuration snippet directory. If this directory is included in the local Kerberos configuration the plugin will be enabled automatically.

This configuration snippet also disables the an2ln module provided by MIT Kerberos if SSSD is configured to use the AD or IPA provider. In those environments sssd_krb5_localauth_plugin can reliably map the system user names to Kerberos principals. A fallback to an2ln might cause issues in environments where users have the privilege to create Kerberos principals on their own which might collide with names of other users used in the system. Other modules provided by MIT Kerberos, e.g. k5login are not affected.

Note: If using “auth_provider = krb5” then sssd_krb5_localauth_plugin is not used, therefore the above text is not applicable.

SEE ALSO

sssd(8), sssd.conf(5), sssd-ldap(5), sssd-ldap-attributes(5), sssd-krb5(5), sssd-simple(5), sssd-ipa(5), sssd-ad(5), sssd-idp(5), sssd-sudo(5), sssd-session-recording(5), sss_cache(8), sss_debuglevel(8), sss_obfuscate(8), sss_seed(8), sssd_krb5_locator_plugin(8), sss_ssh_authorizedkeys(1), sss_ssh_knownhosts(1), sssd-ifp(5), pam_sss(8). sss_rpcidmapd(5)

AUTHORS

The SSSD upstream - https://github.com/SSSD/sssd/