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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | RETURN VALUES | SEE ALSO | STANDARDS | COLOPHON |
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PAM_GET_AUTHTOK(3) Linux-PAM Manual PAM_GET_AUTHTOK(3)
pam_get_authtok, pam_get_authtok_verify, pam_get_authtok_noverify
- get authentication token
#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);
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!
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.
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.
pam(8)
The pam_get_authtok function is a Linux-PAM extensions.
This page is part of the linux-pam (Pluggable Authentication
Modules for Linux) project. Information about the project can be
found at ⟨http://www.linux-pam.org/⟩. If you have a bug report
for this manual page, see ⟨//www.linux-pam.org/⟩. This page was
obtained from the project's upstream Git repository
⟨https://github.com/linux-pam/linux-pam.git⟩ on 2023-12-22. (At
that time, the date of the most recent commit that was found in
the repository was 2023-12-18.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
Linux-PAM Manual 12/22/2023 PAM_GET_AUTHTOK(3)
Pages that refer to this page: pam_get_authtok(3), pam_get_item(3), pam_set_item(3), pam_pwhistory(8), pam_systemd_loadkey(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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