misc_conv(3) — Linux manual page
MISC_CONV(3) Linux-PAM Manual MISC_CONV(3)
NAME
misc_conv - text based conversation function
SYNOPSIS
#include <security/pam_misc.h>
int misc_conv(int num_msg, const struct pam_message **msgm,
struct pam_response **response, void *appdata_ptr);
DESCRIPTION
The misc_conv function is part of libpam_misc and not of the
standard libpam library. This function will prompt the user with
the appropriate comments and obtain the appropriate inputs as
directed by authentication modules.
In addition to simply slotting into the appropriate pam_conv(3),
this function provides some time-out facilities. The function
exports five variables that can be used by an application
programmer to limit the amount of time this conversation function
will spend waiting for the user to type something. The five
variables are as follows:
time_t pam_misc_conv_warn_time;
This variable contains the time (as returned by time(2)) that
the user should be first warned that the clock is ticking. By
default it has the value 0, which indicates that no such
warning will be given. The application may set its value to
sometime in the future, but this should be done prior to
passing control to the Linux-PAM library.
const char *pam_misc_conv_warn_line;
Used in conjunction with pam_misc_conv_warn_time, this
variable is a pointer to the string that will be displayed
when it becomes time to warn the user that the timeout is
approaching. Its default value is a translated version of
“...Time is running out...”, but this can be changed by the
application prior to passing control to Linux-PAM.
time_t pam_misc_conv_die_time;
This variable contains the time (as returned by time(2)) that
the will time out. By default it has the value 0, which
indicates that the conversation function will not timeout.
The application may set its value to sometime in the future,
but this should be done prior to passing control to the
Linux-PAM library.
const char *pam_misc_conv_die_line;
Used in conjunction with pam_misc_conv_die_time, this
variable is a pointer to the string that will be displayed
when the conversation times out. Its default value is a
translated version of “...Sorry, your time is up!”, but this
can be changed by the application prior to passing control to
Linux-PAM.
int pam_misc_conv_died;
Following a return from the Linux-PAM library, the value of
this variable indicates whether the conversation has timed
out. A value of 1 indicates the time-out occurred.
The following two function pointers are available for supporting
binary prompts in the conversation function. They are optimized
for the current incarnation of the libpamc library and are
subject to change.
int (*pam_binary_handler_fn)(void *appdata, pamc_bp_t *prompt_p);
This function pointer is initialized to NULL but can be
filled with a function that provides machine-machine (hidden)
message exchange. It is intended for use with hidden
authentication protocols such as RSA or Diffie-Hellman key
exchanges. (This is still under development.)
int (*pam_binary_handler_free)(void *appdata, pamc_bp_t
*delete_me);
This function pointer is initialized to
PAM_BP_RENEW(delete_me, 0, 0), but can be redefined as
desired by the application.
SEE ALSO
pam_conv(3), pam(8)
STANDARDS
The misc_conv function is part of the libpam_misc Library and not
defined in any standard.
COLOPHON
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
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