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gradm_pam.c
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gradm_pam.c
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/*
* Copyright (C) 2002-2014 Bradley Spengler, Open Source Security, Inc.
* http://www.grsecurity.net spender@grsecurity.net
*
* This file is part of gradm. It constitutes the PAM-based authentication of gradm.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <security/pam_appl.h>
#include <security/pam_misc.h>
#include "gradm.h"
#define PAM_SERVICENAME "gradm"
int gradm_pam_conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr)
{
int i, x;
struct pam_response *response;
char *p;
/* arbitrary OpenSSH-style limiting */
if (num_msg <= 0 || num_msg > 1000)
return PAM_CONV_ERR;
response = malloc(num_msg * sizeof(struct pam_response));
if (response == NULL)
return PAM_CONV_ERR;
for (i = 0; i < num_msg; i++) {
response[i].resp_retcode = 0;
response[i].resp = NULL;
switch (msg[i]->msg_style) {
case PAM_PROMPT_ECHO_ON:
fputs(msg[i]->msg, stdout);
response[i].resp = calloc(1, PAM_MAX_RESP_SIZE);
if (response[i].resp == NULL)
failure("calloc");
p = NULL;
while (p == NULL)
p = fgets(response[i].resp, PAM_MAX_RESP_SIZE, stdin);
while (*p) {
if (*p == '\n')
*p = '\0';
else
p++;
}
break;
case PAM_PROMPT_ECHO_OFF:
p = getpass(msg[i]->msg);
if (p == NULL)
failure("getpass");
response[i].resp = strdup(p);
/* zero out static buffer */
memset(p, 0, strlen(p));
if (response[i].resp == NULL)
failure("strdup");
break;
case PAM_ERROR_MSG:
fputs(msg[i]->msg, stderr);
break;
case PAM_TEXT_INFO:
fputs(msg[i]->msg, stdout);
break;
default:
for (x = i; x >= 0; x--) {
if (response[x].resp != NULL) {
memset(response[x].resp, 0, strlen(response[x].resp));
free(response[x].resp);
response[x].resp = NULL;
}
}
free(response);
return PAM_CONV_ERR;
}
}
*resp = response;
return PAM_SUCCESS;
}
int main(int argc, char *argv[])
{
pam_handle_t *pamh = NULL;
int retval;
struct pam_conv conv = { gradm_pam_conv, NULL };
struct gr_arg_wrapper wrapper;
struct gr_arg arg;
int fd;
if (argc != 2)
exit(EXIT_FAILURE);
wrapper.version = GRADM_VERSION;
wrapper.size = sizeof(struct gr_arg);
wrapper.arg = &arg;
arg.mode = GRADM_STATUS;
if ((fd = open(GRDEV_PATH, O_WRONLY)) < 0) {
fprintf(stderr, "Could not open %s.\n", GRDEV_PATH);
failure("open");
}
retval = write(fd, &wrapper, sizeof(struct gr_arg_wrapper));
close(fd);
if (retval != 1)
exit(EXIT_FAILURE);
retval = pam_start(PAM_SERVICENAME, argv[1], &conv, &pamh);
if (retval == PAM_SUCCESS)
retval = pam_authenticate(pamh, 0);
if (retval == PAM_SUCCESS)
retval = pam_acct_mgmt(pamh, 0);
if (retval == PAM_AUTHTOK_EXPIRED)
retval = pam_chauthtok(pamh, 0);
if (pamh)
pam_end(pamh, retval);
if (retval != PAM_SUCCESS)
exit(EXIT_FAILURE);
return EXIT_SUCCESS;
}