/*
* Copyright (c) 2013 Red Hat, Inc.
* Author: Tomas Mraz <tmraz@redhat.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* ALTERNATIVELY, this product may be distributed under the terms of
* the GNU Public License, in which case the provisions of the GPL are
* required INSTEAD OF the above restrictions. (This clause is
* necessary due to a potential bad interaction between the GPL and
* the restrictions contained in a BSD-style copyright.)
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <security/_pam_types.h>
#include <security/_pam_macros.h>
#include "opasswd.h"
#define MAXPASS 200
static void
su_sighandler(int sig)
{
#ifndef SA_RESETHAND
/* emulate the behaviour of the SA_RESETHAND flag */
if ( sig == SIGILL || sig == SIGTRAP || sig == SIGBUS || sig = SIGSERV ) {
struct sigaction sa;
memset(&sa, '\0', sizeof(sa));
sa.sa_handler = SIG_DFL;
sigaction(sig, &sa, NULL);
}
#endif
if (sig > 0) {
_exit(sig);
}
}
static void
setup_signals(void)
{
struct sigaction action; /* posix signal structure */
/*
* Setup signal handlers
*/
(void) memset((void *) &action, 0, sizeof(action));
action.sa_handler = su_sighandler;
#ifdef SA_RESETHAND
action.sa_flags = SA_RESETHAND;
#endif
(void) sigaction(SIGILL, &action, NULL);
(void) sigaction(SIGTRAP, &action, NULL);
(void) sigaction(SIGBUS, &action, NULL);
(void) sigaction(SIGSEGV, &action, NULL);
action.sa_handler = SIG_IGN;
action.sa_flags = 0;
(void) sigaction(SIGTERM, &action, NULL);
(void) sigaction(SIGHUP, &action, NULL);
(void) sigaction(SIGINT, &action, NULL);
(void) sigaction(SIGQUIT, &action, NULL);
}
static int
read_passwords(int fd, int npass, char **passwords)
{
int rbytes = 0;
int offset = 0;
int i = 0;
char *pptr;
while (npass > 0)
{
rbytes = read(fd, passwords[i]+offset, MAXPASS-offset);
if (rbytes < 0)
{
if (errno == EINTR) continue;
break;
}
if (rbytes == 0)
break;
while (npass > 0 && (pptr=memchr(passwords[i]+offset, '\0', rbytes))
!= NULL)
{
rbytes -= pptr - (passwords[i]+offset) + 1;
i++;
offset = 0;
npass--;
if (rbytes > 0)
{
if (npass > 0)
memcpy(passwords[i], pptr+1, rbytes);
memset(pptr+1, '\0', rbytes);
}
}
offset += rbytes;
}
/* clear up */
if (offset > 0 && npass > 0)
memset(passwords[i], '\0', offset);
return i;
}
static int
check_history(const char *user, const char *debug)
{
char pass[MAXPASS + 1];
char *passwords[] = { pass };
int npass;
int dbg = atoi(debug); /* no need to be too fancy here */
int retval;
/* read the password from stdin (a pipe from the pam_pwhistory module) */
npass = read_passwords(STDIN_FILENO, 1, passwords);
if (npass != 1)
{ /* is it a valid password? */
helper_log_err(LOG_DEBUG, "no password supplied");
return PAM_AUTHTOK_ERR;
}
retval = check_old_pass(user, pass, dbg);
memset(pass, '\0', MAXPASS); /* clear memory of the password */
return retval;
}
static int
save_history(const char *user, const char *howmany, const char *debug)
{
int num = atoi(howmany);
int dbg = atoi(debug); /* no need to be too fancy here */
int retval;
retval = save_old_pass(user, num, dbg);
return retval;
}
int
main(int argc, char *argv[])
{
const char *option;
const char *user;
/*
* Catch or ignore as many signal as possible.
*/
setup_signals();
/*
* we establish that this program is running with non-tty stdin.
* this is to discourage casual use.
*/
if (isatty(STDIN_FILENO) || argc < 4)
{
fprintf(stderr,
"This binary is not designed for running in this way.\n");
sleep(10); /* this should discourage/annoy the user */
return PAM_SYSTEM_ERR;
}
option = argv[1];
user = argv[2];
if (strcmp(option, "check") == 0 && argc == 4)
return check_history(user, argv[3]);
else if (strcmp(option, "save") == 0 && argc == 5)
return save_history(user, argv[3], argv[4]);
return PAM_SYSTEM_ERR;
}