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PAM_USERTYPE

Section: Linux-PAM Manual (8)
Updated: 02/02/2026
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NAME

pam_usertype - check if the authenticated user is a system or regular account

SYNOPSIS

pam_usertype.so [flag...] {condition}

DESCRIPTION

pam_usertype.so is designed to succeed or fail authentication based on type of the account of the authenticated user. The type of the account is decided with help of SYS_UID_MAX settings in /etc/login.defs. One use is to select whether to load other modules based on this test.

The module should be given only one condition as module argument. Authentication will succeed only if the condition is met.

OPTIONS

The following flags are supported:

use_uid

: Evaluate conditions using the account of the user whose UID the application is running under instead of the user being authenticated.

audit

: Log unknown users to the system log.

Available conditions are:

issystem

: Succeed if the user is a system user.

isregular

: Succeed if the user is a regular user.

MODULE TYPES PROVIDED

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

RETURN VALUES

PAM_SUCCESS

: The condition was true.

PAM_BUF_ERR

: Memory buffer error.

PAM_CONV_ERR

: The conversation method supplied by the application failed to obtain the username.

PAM_INCOMPLETE

: The conversation method supplied by the application returned PAM_CONV_AGAIN.

PAM_AUTH_ERR

: The condition was false.

PAM_SERVICE_ERR

: A service error occurred or the arguments can't be parsed correctly.

PAM_USER_UNKNOWN

: User was not found.

EXAMPLES

Skip remaining modules if the user is a system user:

account sufficient pam_usertype.so issystem

AUTHOR

Pavel Březina <pbrezina@redhat.com>