PAM_GET_AUTHTOK
Section: Linux-PAM Manual (3)
Updated: 11/25/2020
Page Index
NAME
pam_get_authtok, pam_get_authtok_verify, pam_get_authtok_noverify - get authentication token
SYNOPSIS
#include <security/pam_ext.h>
-
int pam_get_authtok(pam_handle_t *pamh, int item, const char **authtok, const char *prompt);
-
int pam_get_authtok_noverify(pam_handle_t *pamh, const char **authtok, const char *prompt);
-
int pam_get_authtok_verify(pam_handle_t *pamh, const char **authtok, const char *prompt);
DESCRIPTION
The
pam_get_authtok
function returns the cached authentication token, or prompts the user if no token is currently cached. It is intended for internal use by Linux-PAM and PAM service modules. Upon successful return,
authtok
contains a pointer to the value of the authentication token. Note, this is a pointer to the
actual
data and should
not
be
free()'ed or over-written!
The
prompt
argument specifies a prompt to use if no token is cached. If a NULL pointer is given,
pam_get_authtok
uses pre-defined prompts.
The following values are supported for
item:
PAM_AUTHTOK
-
Returns the current authentication token. Called from
pam_sm_chauthtok(3)
pam_get_authtok
will ask the user to confirm the new token by retyping it. If a prompt was specified, "Retype" will be used as prefix.
PAM_OLDAUTHTOK
-
Returns the previous authentication token when changing authentication tokens.
The
pam_get_authtok_noverify
function can only be used for changing the password (from
pam_sm_chauthtok(3)). It returns the cached authentication token, or prompts the user if no token is currently cached. The difference to
pam_get_authtok
is, that this function does not ask a second time for the password to verify it. Upon successful return,
authtok
contains a pointer to the value of the authentication token. Note, this is a pointer to the
actual
data and should
not
be
free()'ed or over-written!
The
pam_get_authtok_verify
function can only be used to verify a password for mistypes gotten by
pam_get_authtok_noverify(3). This function asks a second time for the password and verify it with the password provided by
authtok
argument. In case of an error, the value of
authtok
is undefined. Else this argument will point to the
actual
data and should
not
be
free()'ed or over-written!
OPTIONS
pam_get_authtok
honours the following module options:
try_first_pass
-
Before prompting the user for their password, the module first tries the previous stacked module's password in case that satisfies this module as well.
use_first_pass
-
The argument
use_first_pass
forces the module to use a previous stacked modules password and will never prompt the user - if no password is available or the password is not appropriate, the user will be denied access.
use_authtok
-
When password changing enforce the module to set the new token to the one provided by a previously stacked
password
module. If no token is available token changing will fail.
authtok_type=XXX
-
The default action is for the module to use the following prompts when requesting passwords: "New UNIX password: " and "Retype UNIX password: ". The example word
UNIX
can be replaced with this option, by default it is empty.
RETURN VALUES
PAM_AUTH_ERR
-
Authentication token could not be retrieved.
PAM_AUTHTOK_ERR
-
New authentication could not be retrieved.
PAM_SUCCESS
-
Authentication token was successfully retrieved.
PAM_SYSTEM_ERR
-
No space for an authentication token was provided.
PAM_TRY_AGAIN
-
New authentication tokens mismatch.
SEE ALSO
pam(8)
STANDARDS
The
pam_get_authtok
function is a Linux-PAM extensions.