NAME
pam_authtok_get − authentication and password management module
SYNOPSIS
pam_authtok_get.so.1
DESCRIPTION
The pam_authtok_get service module provides password prompting funtionality to the PAM stack. It implements pam_sm_authenticate() and pam_sm_chauthtok(), providing functionality to both the Authentication Stack and the Password Management Stack.
Authentication
Service
The implementation of pam_sm_authenticate(3PAM)
prompts the user name if not set and then tries to get the
authentication token from the pam handle. If the token is
not set, it then prompts the user for a password and stores
it in the PAM item PAM_AUTHTOK. This module is
meant to be the first module on an authentication stack
where users are to authenticate using a keyboard.
Password
Management Service
Due to the nature of the PAM Password Management stack
traversal mechanism, the pam_sm_chauthtok(3PAM)
function is called twice. Once with the
PAM_PRELIM_CHECK flag, and one with the
PAM_UPDATE_AUTHTOK flag.
In the first (PRELIM) invocation, the implementation of pam_sm_chauthtok(3PAM) moves the contents of the PAM_AUTHTOK (current authentication token) to PAM_OLDAUTHTOK, and subsequentially prompts the user for a new password. This new password is stored in PAM_AUTHTOK.
If a previous module has set PAM_AUTHTOK prior to the invocation of pam_authtok_get, this module turns into a NO-OP and immediately returns PAM_SUCCESS.
In the second (UPDATE) invocation, the user is prompted to Re-enter his password. The pam_sm_chauthtok implementation verifies this reentered password with the password stored in PAM_AUTHTOK. If the passwords match, the module returns PAM_SUCCESS.
The following option can be passed to the module:
|
debug |
syslog(3C) debugging information at the LOG_DEBUG level |
RETURN VALUES
The
authentication service returns the following values:
PAM_SUCCESS
Successfully obtains authentication token
PAM_SYSTEM_ERR
Fails to retrieve username, username is NULL or empty
The password
management service returns the following values:
PAM_SUCCESS
Successfully obtains authentication token
PAM_AUTHTOK_ERR
Authentication token manipulation error
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
SEE ALSO
pam(3PAM), pam_authenticate(3PAM), syslog(3C), libpam(3LIB), pam.conf(4), attributes(5), pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix(5), pam_unix_account(5), pam_unix_auth(5), pam_unix_session(5)
NOTES
The interfaces in libpam(3LIB) are MT-Safe only if each thread within the multi-threaded application uses its own PAM handle.
The pam_unix(5) module might not be supported in a future release. Similar functionality is provided by pam_authtok_check(5), pam_authtok_get(5), pam_authtok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5), pam_unix_auth(5), and pam_unix_session(5).