PAM_AUTHTOK_GET(5)PAM_AUTHTOK_GET(5)NAMEpam_authtok_get - authentication and password management module
SYNOPSIS
pam_authtok_get.so.1
DESCRIPTION
The pam_authtok_get service module provides password prompting funtion‐
ality 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 pass‐
word 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 mecha‐
nism, 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_chauth‐
tok(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_OLDAUTHTOK 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
ERRORS
The authentication service returns the following error codes:
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 error codes:
PAM_SUCCESS
Successfully obtains authentication token
PAM_AUTHTOK_ERR
Authentication token manipulation error
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────────────┤
│Interface Stability │ Evolving │
├────────────────────┼─────────────────────────┤
│MT Level │ MT-Safe with exceptions │
└────────────────────┴─────────────────────────┘
SEE ALSOpam(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_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 is no longer supported. Similar functionality is
provided by pam_authtok_check(5), pam_authtok_get(5), pam_auth‐
tok_store(5), pam_dhkeys(5), pam_passwd_auth(5), pam_unix_account(5),
pam_unix_auth(5), and pam_unix_session(5).
Dec 14, 2004 PAM_AUTHTOK_GET(5)
