PAM_AUTHTOK_GET(7) Standards, Environments, and Macros PAM_AUTHTOK_GET(7)
pam_authtok_get - authentication and password management module
pam_authtok_get.so.1
The pam_authtok_get service module provides password prompting
functionality to the PAM stack. It implements
pam_sm_authenticate(3PAM) and pam_sm_chauthtok(3PAM), providing
functionality to both the Authentication Stack and the Password
Management Stack.
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.
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 subsequently 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
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
See attributes(7) for descriptions of the following attributes:
+--------------------+-------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------------+
|Interface Stability | Evolving |
+--------------------+-------------------------+
|MT Level | MT-Safe with exceptions |
+--------------------+-------------------------+
pam(3PAM), pam_authenticate(3PAM), pam_sm_authenticate(3PAM),
pam_sm_chauthtok(3PAM), syslog(3C), libpam(3LIB), pam.conf(5),
attributes(7), pam_authtok_check(7), pam_authtok_store(7),
pam_dhkeys(7), pam_passwd_auth(7), pam_unix_account(7),
pam_unix_auth(7), pam_unix_session(7)
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(7) module is no longer supported. Similar functionality
is provided by pam_authtok_check(7), pam_authtok_get(7),
pam_authtok_store(7), pam_dhkeys(7), pam_passwd_auth(7),
pam_unix_account(7), pam_unix_auth(7), and pam_unix_session(7).
August 9, 2023 PAM_AUTHTOK_GET(7)
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
functionality to the PAM stack. It implements
pam_sm_authenticate(3PAM) and pam_sm_chauthtok(3PAM), 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 subsequently 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(7) for descriptions of the following attributes:
+--------------------+-------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------------+
|Interface Stability | Evolving |
+--------------------+-------------------------+
|MT Level | MT-Safe with exceptions |
+--------------------+-------------------------+
SEE ALSO
pam(3PAM), pam_authenticate(3PAM), pam_sm_authenticate(3PAM),
pam_sm_chauthtok(3PAM), syslog(3C), libpam(3LIB), pam.conf(5),
attributes(7), pam_authtok_check(7), pam_authtok_store(7),
pam_dhkeys(7), pam_passwd_auth(7), pam_unix_account(7),
pam_unix_auth(7), pam_unix_session(7)
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(7) module is no longer supported. Similar functionality
is provided by pam_authtok_check(7), pam_authtok_get(7),
pam_authtok_store(7), pam_dhkeys(7), pam_passwd_auth(7),
pam_unix_account(7), pam_unix_auth(7), and pam_unix_session(7).
August 9, 2023 PAM_AUTHTOK_GET(7)