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/*
* $Id: misc_conv.c,v 1.5 1997/01/04 20:16:48 morgan Exp morgan $
*
* A generic conversation function for text based applications
*
* Written by Andrew Morgan <morgan@linux.kernel.org>
*
* $Log: misc_conv.c,v $
* Revision 1.5 1997/01/04 20:16:48 morgan
* removed getpass. Replaced with POSIX code for same function which
* also observes timeouts specified by the parent application
*
* Revision 1.4 1996/12/01 03:26:51 morgan
* *** empty log message ***
*
* Revision 1.3 1996/11/10 20:10:01 morgan
* sgi definition
*
* Revision 1.2 1996/07/07 23:59:56 morgan
* changed the name of the misc include file
*
* Revision 1.1 1996/05/02 05:17:06 morgan
* Initial revision
*/
#ifdef linux
#define _GNU_SOURCE
#include <features.h>
#endif
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <termios.h>
#include <time.h>
#include <unistd.h>
#include <security/pam_appl.h>
#include <security/pam_misc.h>
#define INPUTSIZE PAM_MAX_MSG_SIZE /* maximum length of input+1 */
#define CONV_ECHO_ON 1 /* types of echo state */
#define CONV_ECHO_OFF 0
/*
* external timeout definitions - these can be overriden by the
* application.
*/
time_t pam_misc_conv_warn_time = 0; /* time when we warn */
time_t pam_misc_conv_die_time = 0; /* time when we timeout */
const char *pam_misc_conv_warn_line = "..\a.Time is running out...\n";
const char *pam_misc_conv_die_line = "..\a.Sorry, your time is up!\n";
int pam_misc_conv_died=0; /* application can probe this for timeout */
static void pam_misc_conv_delete_binary(void **delete_me)
{
if (delete_me && *delete_me) {
unsigned char *packet = *(unsigned char **)delete_me;
int length;
length = 4+(packet[0]<<24)+(packet[1]<<16)+(packet[2]<<8)+packet[3];
memset(packet, 0, length);
free(packet);
*delete_me = packet = NULL;
}
}
/* These function pointers are for application specific binary
conversations. One or both of the arguments to the first function
must be non-NULL. The first function must return PAM_SUCCESS or
PAM_CONV_ERR. If input is non-NULL, a response is expected, this
response should be malloc()'d and will eventually be free()'d by
the calling module. The structure of this malloc()'d response is as
follows:
{ int length, char data[length] }
For convenience, the pointer used by the two function pointer
prototypes is 'void *'.
The ...free() fn pointer is used to discard a binary message that
is not of the default form. It should be explicitly overwritten
when using some other convention for the structure of a binary
prompt (not recommended). */
int (*pam_binary_handler_fn)(const void *send, void **receive) = NULL;
void (*pam_binary_handler_free)(void **packet_p) = pam_misc_conv_delete_binary;
/* the following code is used to get text input */
volatile static int expired=0;
/* return to the previous signal handling */
static void reset_alarm(struct sigaction *o_ptr)
{
(void) alarm(0); /* stop alarm clock - if still ticking */
(void) sigaction(SIGALRM, o_ptr, NULL);
}
/* this is where we intercept the alarm signal */
static void time_is_up(int ignore)
{
expired = 1;
}
/* set the new alarm to hit the time_is_up() function */
static int set_alarm(int delay, struct sigaction *o_ptr)
{
struct sigaction new_sig;
sigemptyset(&new_sig.sa_mask);
new_sig.sa_flags = 0;
new_sig.sa_handler = time_is_up;
if ( sigaction(SIGALRM, &new_sig, o_ptr) ) {
return 1; /* setting signal failed */
}
if ( alarm(delay) ) {
(void) sigaction(SIGALRM, o_ptr, NULL);
return 1; /* failed to set alarm */
}
return 0; /* all seems to have worked */
}
/* return the number of seconds to next alarm. 0 = no delay, -1 = expired */
static int get_delay(void)
{
time_t now;
expired = 0; /* reset flag */
(void) time(&now);
/* has the quit time past? */
if (pam_misc_conv_die_time && now >= pam_misc_conv_die_time) {
fprintf(stderr,"%s",pam_misc_conv_die_line);
pam_misc_conv_died = 1; /* note we do not reset the die_time */
return -1; /* time is up */
}
/* has the warning time past? */
if (pam_misc_conv_warn_time && now >= pam_misc_conv_warn_time) {
fprintf(stderr, "%s", pam_misc_conv_warn_line);
pam_misc_conv_warn_time = 0; /* reset warn_time */
/* indicate remaining delay - if any */
return (pam_misc_conv_die_time ? pam_misc_conv_die_time - now:0 );
}
/* indicate possible warning delay */
if (pam_misc_conv_warn_time)
return (pam_misc_conv_warn_time - now);
else if (pam_misc_conv_die_time)
return (pam_misc_conv_die_time - now);
else
return 0;
}
/* read a line of input string, giving prompt when appropriate */
static char *read_string(int echo, const char *prompt)
{
struct termios term_before, term_tmp;
char line[INPUTSIZE];
struct sigaction old_sig;
int delay, nc, have_term=0;
D(("called with echo='%s', prompt='%s'.", echo ? "ON":"OFF" , prompt));
if (isatty(STDIN_FILENO)) { /* terminal state */
/* is a terminal so record settings and flush it */
if ( tcgetattr(STDIN_FILENO, &term_before) != 0 ) {
D(("<error: failed to get terminal settings>"));
return NULL;
}
memcpy(&term_tmp, &term_before, sizeof(term_tmp));
if (!echo) {
term_tmp.c_lflag &= ~(ECHO);
}
have_term = 1;
} else if (!echo) {
D(("<warning: cannot turn echo off>"));
}
/* set up the signal handling */
delay = get_delay();
/* reading the line */
while (delay >= 0) {
fprintf(stderr, "%s", prompt);
/* this may, or may not set echo off -- drop pending input */
if (have_term)
(void) tcsetattr(STDIN_FILENO, TCSAFLUSH, &term_tmp);
if ( delay > 0 && set_alarm(delay, &old_sig) ) {
D(("<failed to set alarm>"));
break;
} else {
nc = read(STDIN_FILENO, line, INPUTSIZE-1);
if (have_term) {
(void) tcsetattr(STDIN_FILENO, TCSADRAIN, &term_before);
if (!echo || expired) /* do we need a newline? */
fprintf(stderr,"\n");
}
if ( delay > 0 ) {
reset_alarm(&old_sig);
}
if (expired) {
delay = get_delay();
} else if (nc > 0) { /* we got some user input */
char *input;
if (nc > 0 && line[nc-1] == '\n') { /* <NUL> terminate */
line[--nc] = '\0';
} else {
line[nc] = '\0';
}
input = x_strdup(line);
_pam_overwrite(line);
return input; /* return malloc()ed string */
} else if (nc == 0) { /* Ctrl-D */
D(("user did not want to type anything"));
fprintf(stderr, "\n");
break;
}
}
}
/* getting here implies that the timer expired */
if (have_term)
(void) tcsetattr(STDIN_FILENO, TCSADRAIN, &term_before);
memset(line, 0, INPUTSIZE); /* clean up */
return NULL;
}
/* end of read_string functions */
int misc_conv(int num_msg, const struct pam_message **msgm,
struct pam_response **response, void *appdata_ptr)
{
int count=0;
struct pam_response *reply;
if (num_msg <= 0)
return PAM_CONV_ERR;
D(("allocating empty response structure array."));
reply = (struct pam_response *) calloc(num_msg,
sizeof(struct pam_response));
if (reply == NULL) {
D(("no memory for responses"));
return PAM_CONV_ERR;
}
D(("entering conversation function."));
for (count=0; count < num_msg; ++count) {
char *string=NULL;
switch (msgm[count]->msg_style) {
case PAM_PROMPT_ECHO_OFF:
string = read_string(CONV_ECHO_OFF,msgm[count]->msg);
if (string == NULL) {
goto failed_conversation;
}
break;
case PAM_PROMPT_ECHO_ON:
string = read_string(CONV_ECHO_ON,msgm[count]->msg);
if (string == NULL) {
goto failed_conversation;
}
break;
case PAM_ERROR_MSG:
if (fprintf(stderr,"%s\n",msgm[count]->msg) < 0) {
goto failed_conversation;
}
break;
case PAM_TEXT_INFO:
if (fprintf(stdout,"%s\n",msgm[count]->msg) < 0) {
goto failed_conversation;
}
break;
case PAM_BINARY_PROMPT:
{
void *pack_out=NULL;
const void *pack_in = msgm[count]->msg;
if (!pam_binary_handler_fn
|| pam_binary_handler_fn(pack_in, &pack_out) != PAM_SUCCESS
|| pack_out == NULL) {
goto failed_conversation;
}
string = (char *) pack_out;
pack_out = NULL;
break;
}
case PAM_BINARY_MSG:
{
const void *pack_in = msgm[count]->msg;
if (!pam_binary_handler_fn
|| pam_binary_handler_fn(pack_in, NULL) != PAM_SUCCESS) {
goto failed_conversation;
}
break;
}
default:
fprintf(stderr, "erroneous conversation (%d)\n"
,msgm[count]->msg_style);
goto failed_conversation;
}
if (string) { /* must add to reply array */
/* add string to list of responses */
reply[count].resp_retcode = 0;
reply[count].resp = string;
string = NULL;
}
}
/* New (0.59+) behavior is to always have a reply - this is
compatable with the X/Open (March 1997) spec. */
*response = reply;
reply = NULL;
return PAM_SUCCESS;
failed_conversation:
if (reply) {
for (count=0; count<num_msg; ++count) {
if (reply[count].resp == NULL) {
continue;
}
switch (msgm[count]->msg_style) {
case PAM_PROMPT_ECHO_ON:
case PAM_PROMPT_ECHO_OFF:
_pam_overwrite(reply[count].resp);
free(reply[count].resp);
break;
case PAM_BINARY_PROMPT:
pam_binary_handler_free((void **) &reply[count].resp);
break;
case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
case PAM_BINARY_MSG:
/* should not actually be able to get here... */
free(reply[count].resp);
}
reply[count].resp = NULL;
}
/* forget reply too */
free(reply);
reply = NULL;
}
return PAM_CONV_ERR;
}
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