PAM_GET_ITEM
Section: Linux-PAM Manual (3)
Updated: 11/25/2020
Page Index
NAME
pam_get_item - getting PAM information
SYNOPSIS
#include <security/pam_modules.h>
-
int pam_get_item(const pam_handle_t *pamh, int item_type, const void **item);
DESCRIPTION
The
pam_get_item
function allows applications and PAM service modules to access and retrieve PAM information of
item_type. Upon successful return,
item
contains a pointer to the value of the corresponding item. Note, this is a pointer to the
actual
data and should
not
be
free()'ed or over-written! The following values are supported for
item_type:
PAM_SERVICE
-
The service name (which identifies that PAM stack that the PAM functions will use to authenticate the program).
PAM_USER
-
The username of the entity under whose identity service will be given. That is, following authentication,
PAM_USER
identifies the local entity that gets to use the service. Note, this value can be mapped from something (eg., "anonymous") to something else (eg. "guest119") by any module in the PAM stack. As such an application should consult the value of
PAM_USER
after each call to a PAM function.
PAM_USER_PROMPT
-
The string used when prompting for a user's name. The default value for this string is a localized version of "login: ".
PAM_TTY
-
The terminal name: prefixed by
/dev/
if it is a device file; for graphical, X-based, applications the value for this item should be the
$DISPLAY
variable.
PAM_RUSER
-
The requesting user name: local name for a locally requesting user or a remote user name for a remote requesting user.
Generally an application or module will attempt to supply the value that is most strongly authenticated (a local account before a remote one. The level of trust in this value is embodied in the actual authentication stack associated with the application, so it is ultimately at the discretion of the system administrator.
PAM_RUSER@PAM_RHOST
should always identify the requesting user. In some cases,
PAM_RUSER
may be NULL. In such situations, it is unclear who the requesting entity is.
PAM_RHOST
-
The requesting hostname (the hostname of the machine from which the
PAM_RUSER
entity is requesting service). That is
PAM_RUSER@PAM_RHOST
does identify the requesting user. In some applications,
PAM_RHOST
may be NULL. In such situations, it is unclear where the authentication request is originating from.
PAM_AUTHTOK
-
The authentication token (often a password). This token should be ignored by all module functions besides
pam_sm_authenticate(3)
and
pam_sm_chauthtok(3). In the former function it is used to pass the most recent authentication token from one stacked module to another. In the latter function the token is used for another purpose. It contains the currently active authentication token.
PAM_OLDAUTHTOK
-
The old authentication token. This token should be ignored by all module functions except
pam_sm_chauthtok(3).
PAM_CONV
-
The pam_conv structure. See
pam_conv(3).
The following additional items are specific to Linux-PAM and should not be used in portable applications:
PAM_FAIL_DELAY
-
A function pointer to redirect centrally managed failure delays. See
pam_fail_delay(3).
PAM_XDISPLAY
-
The name of the X display. For graphical, X-based applications the value for this item should be the
$DISPLAY
variable. This value may be used independently of
PAM_TTY
for passing the name of the display.
PAM_XAUTHDATA
-
A pointer to a structure containing the X authentication data required to make a connection to the display specified by
PAM_XDISPLAY, if such information is necessary. See
pam_xauth_data(3).
PAM_AUTHTOK_TYPE
-
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 item, by default it is empty. This item is used by
pam_get_authtok(3).
If a service module wishes to obtain the name of the user, it should not use this function, but instead perform a call to
pam_get_user(3).
Only a service module is privileged to read the authentication tokens, PAM_AUTHTOK and PAM_OLDAUTHTOK.
RETURN VALUES
PAM_BAD_ITEM
-
The application attempted to set an undefined or inaccessible item.
PAM_BUF_ERR
-
Memory buffer error.
PAM_PERM_DENIED
-
The value of
item
was NULL.
PAM_SUCCESS
-
Data was successful updated.
PAM_SYSTEM_ERR
-
The
pam_handle_t
passed as first argument was invalid.
SEE ALSO
pam_set_item(3),
pam_strerror(3)