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PAM_UNIX(8) FreeBSD System Manager's Manual PAM_UNIX(8)
NAME
pam_unix - UNIX PAM module
SYNOPSIS
[service-name] module-type control-flag pam_unix [options]
DESCRIPTION
The UNIX authentication service module for PAM, pam_unix provides
functionality for three PAM categories: authentication, account
management, and password management. In terms of the module-type
parameter, they are the "auth", "account", and "password" features. It
also provides a null function for session management.
UNIX Ss Authentication Module
The UNIX authentication component provides functions to verify the
identity of a user (pam_sm_authenticate()), which obtains the relevant
passwd(5) entry. It prompts the user for a password and verifies that
this is correct with crypt(3).
The following options may be passed to the authentication module:
debug syslog(3) debugging information at LOG_DEBUG level.
use_first_pass If the authentication module is not the first in the
stack, and a previous module obtained the user's
password, that password is used to authenticate the user.
If this fails, the authentication module returns failure
without prompting the user for a password. This option
has no effect if the authentication module is the first
in the stack, or if no previous modules obtained the
user's password.
try_first_pass This option is similar to the use_first_pass option,
except that if the previously obtained password fails,
the user is prompted for another password.
auth_as_self This option will require the user to authenticate
themselves as themselves, not as the account they are
attempting to access. This is primarily for services
like su(1), where the user's ability to retype their own
password might be deemed sufficient.
nullok If the password database has no password for the entity
being authenticated, then this option will forgo password
prompting, and silently allow authentication to succeed.
NOTE: If pam_unix is invoked by a process that does not
have the privileges required to access the password
database (in most cases, this means root privileges), the
nullok option may cause pam_unix to allow any user to log
in with any password.
emptyok If the password database contains the password for the
entity being authenticated, but the password matches an
empty string, then this option will forgo password
prompting, and silently allow authentication to succeed.
nis_pass Use only the NIS password database. This will cause an
authentication failure if the system is not configured to
use NIS.
UNIX Ss Account Management Module
The UNIX account management component provides a function to perform
account management, pam_sm_acct_mgmt(). The function verifies that the
authenticated user is allowed to log into the local user account by
checking the following criteria:
- locked status of the account compatible with pw(8) lock;
- the password expiry date from passwd(5);
- login.conf(5) restrictions on the remote host, login time, and
tty.
The following options may be passed to the management module:
debug syslog(3) debugging information at LOG_DEBUG level.
UNIX Ss Password Management Module
The UNIX password management component provides a function to perform
password management, pam_sm_chauthtok(). The function changes the user's
password.
The following options may be passed to the password module:
debug syslog(3) debugging information at LOG_DEBUG level.
no_warn suppress warning messages to the user. These messages
include reasons why the user's authentication attempt was
declined.
local_pass forces the password module to change a local password in
favour of a NIS one.
nis_pass forces the password module to change a NIS password in
favour of a local one.
FILES
/etc/master.passwd default UNIX password database.
SEE ALSO
passwd(1), getlogin(2), crypt(3), getpwent(3), syslog(3),
nsswitch.conf(5), passwd(5), pam(3), pw(8), yp(8)
BUGS
The pam_unix module ignores the PAM_CHANGE_EXPIRED_AUTHTOK flag.
FreeBSD 14.0-RELEASE-p11 April 3, 2020 FreeBSD 14.0-RELEASE-p11