pam_sss man page

pam_sss — PAM module for SSSD

Synopsis [quiet] [forward_pass] [use_first_pass] [use_authtok] [retry=N] [ignore_unknown_user] [ignore_authinfo_unavail] [domains=X] [allow_missing_name] [prompt_always] [try_cert_auth] [require_cert_auth]

Description is the PAM interface to the System Security Services daemon (SSSD). Errors and results are logged through syslog(3) with the LOG_AUTHPRIV facility.



Suppress log messages for unknown users.


If forward_pass is set the entered password is put on the stack for other PAM modules to use.


The argument use_first_pass forces the module to use a previous stacked modules password and will never prompt the user - if no password is available or the password is not appropriate, the user will be denied access.


When password changing enforce the module to set the new password to the one provided by a previously stacked password module.


If specified the user is asked another N times for a password if authentication fails. Default is 0.

Please note that this option might not work as expected if the application calling PAM handles the user dialog on its own. A typical example is sshd with PasswordAuthentication.


If this option is specified and the user does not exist, the PAM module will return PAM_IGNORE. This causes the PAM framework to ignore this module.


Specifies that the PAM module should return PAM_IGNORE if it cannot contact the SSSD daemon. This causes the PAM framework to ignore this module.


Allows the administrator to restrict the domains a particular PAM service is allowed to authenticate against. The format is a comma-separated list of SSSD domain names, as specified in the sssd.conf file.

NOTE: Must be used in conjunction with the “pam_trusted_users” and “pam_public_domains” options. Please see the sssd.conf(5) manual page for more information on these two PAM responder options.


The main purpose of this option is to let SSSD determine the user name based on additional information, e.g. the certificate from a Smartcard.

The current use case are login managers which can monitor a Smartcard reader for card events. In case a Smartcard is inserted the login manager will call a PAM stack which includes a line like

auth sufficient allow_missing_name

In this case SSSD will try to determine the user name based on the content of the Smartcard, returns it to pam_sss which will finally put it on the PAM stack.


Always prompt the user for credentials. With this option credentials requested by other PAM modules, typically a password, will be ignored and pam_sss will prompt for credentials again. Based on the pre-auth reply by SSSD pam_sss might prompt for a password, a Smartcard PIN or other credentials.


Try to use certificate based authentication, i.e. authentication with a Smartcard or similar devices. If a Smartcard is available and the service is allowed for Smartcard authentication the user will be prompted for a PIN and the certificate based authentication will continue

If no Smartcard is available or certificate based authentication is not allowed for the current service PAM_AUTHINFO_UNAVAIL is returned.


Do certificate based authentication, i.e. authentication with a Smartcard or similar devices. If a Smartcard is not available the user will be prompted to insert one. SSSD will wait for a Smartcard until the timeout defined by p11_wait_for_card_timeout passed, please see sssd.conf(5) for details.

If no Smartcard is available after the timeout or certificate based authentication is not allowed for the current service PAM_AUTHINFO_UNAVAIL is returned.

Module Types Provided

All module types (account, auth, password and session) are provided.

If SSSD's PAM responder is not running, e.g. if the PAM responder socket is not available, pam_sss will return PAM_USER_UNKNOWN when called as account module to avoid issues with users from other sources during access control.


If a password reset by root fails, because the corresponding SSSD provider does not support password resets, an individual message can be displayed. This message can e.g. contain instructions about how to reset a password.

The message is read from the file pam_sss_pw_reset_message.LOC where LOC stands for a locale string returned by setlocale(3). If there is no matching file the content of pam_sss_pw_reset_message.txt is displayed. Root must be the owner of the files and only root may have read and write permissions while all other users must have only read permissions.

These files are searched in the directory /etc/sssd/customize/DOMAIN_NAME/. If no matching file is present a generic message is displayed.

See Also

sssd(8), sssd.conf(5), sssd-ldap(5), sssd-krb5(5), sssd-simple(5), sssd-ipa(5), sssd-ad(5), sssd-files(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(8), sss_ssh_knownhostsproxy(8), sssd-ifp(5), pam_sss(8). sss_rpcidmapd(5) sssd-systemtap(5)


The SSSD upstream -

Referenced By

idmap_sss(8), sss_cache(8), sssctl(8), sssd(8), sssd-ad(5), sssd.conf(5), sss_debuglevel(8), sssd-files(5), sssd-ifp(5), sssd-ipa(5), sssd-krb5(5), sssd_krb5_locator_plugin(8), sssd-ldap(5), sssd-session-recording(5), sssd-simple(5), sssd-sudo(5), sssd-systemtap(5), sss_obfuscate(8), sss_override(8), sss_seed(8), sss_ssh_authorizedkeys(1), sss_ssh_knownhostsproxy(1).

07/05/2019 SSSD Manual pages