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/*
* This program is designed to run setuid(root) or with sufficient
* privilege to read all of the unix password databases. It is designed
* to provide a mechanism for the current user (defined by this
* process's uid) to verify their own password.
*
* The password is read from the standard input. The exit status of
* this program indicates whether the user is authenticated or not.
*
* Copyright information is located at the end of the file.
*
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <pwd.h>
#include <shadow.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#ifdef HAVE_LIBAUDIT
#include <libaudit.h>
#endif
#include <security/_pam_types.h>
#include <security/_pam_macros.h>
#include "passverify.h"
static int _check_expiry(const char *uname)
{
struct spwd *spent;
struct passwd *pwent;
int retval;
int daysleft;
retval = get_account_info(uname, &pwent, &spent);
if (retval != PAM_SUCCESS) {
helper_log_err(LOG_ERR, "could not obtain user info (%s)", uname);
printf("-1\n");
return retval;
}
if (spent == NULL) {
printf("-1\n");
return retval;
}
retval = check_shadow_expiry(spent, &daysleft);
printf("%d\n", daysleft);
return retval;
}
#ifdef HAVE_LIBAUDIT
static int _audit_log(int type, const char *uname, int rc)
{
int audit_fd;
audit_fd = audit_open();
if (audit_fd < 0) {
/* You get these error codes only when the kernel doesn't have
* audit compiled in. */
if (errno == EINVAL || errno == EPROTONOSUPPORT ||
errno == EAFNOSUPPORT)
return PAM_SUCCESS;
helper_log_err(LOG_CRIT, "audit_open() failed: %m");
return PAM_AUTH_ERR;
}
rc = audit_log_acct_message(audit_fd, type, NULL, "PAM:unix_chkpwd",
uname, -1, NULL, NULL, NULL, rc == PAM_SUCCESS);
if (rc == -EPERM && geteuid() != 0) {
rc = 0;
}
audit_close(audit_fd);
return rc < 0 ? PAM_AUTH_ERR : PAM_SUCCESS;
}
#endif
int main(int argc, char *argv[])
{
char pass[MAXPASS + 1];
char *option;
int npass, nullok;
int blankpass = 0;
int retval = PAM_AUTH_ERR;
char *user;
char *passwords[] = { pass };
/*
* 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. It does *NOT* prevent an
* intruder from repeatadly running this program to determine the
* password of the current user (brute force attack, but one for
* which the attacker must already have gained access to the user's
* account).
*/
if (isatty(STDIN_FILENO) || argc != 3 ) {
helper_log_err(LOG_NOTICE
,"inappropriate use of Unix helper binary [UID=%d]"
,getuid());
#ifdef HAVE_LIBAUDIT
_audit_log(AUDIT_ANOM_EXEC, getuidname(getuid()), PAM_SYSTEM_ERR);
#endif
fprintf(stderr
,"This binary is not designed for running in this way\n"
"-- the system administrator has been informed\n");
sleep(10); /* this should discourage/annoy the user */
return PAM_SYSTEM_ERR;
}
/*
* Determine what the current user's name is.
* We must thus skip the check if the real uid is 0.
*/
if (getuid() == 0) {
user=argv[1];
}
else {
user = getuidname(getuid());
/* if the caller specifies the username, verify that user
matches it */
if (strcmp(user, argv[1])) {
user = argv[1];
/* no match -> permanently change to the real user and proceed */
if (setuid(getuid()) != 0)
return PAM_AUTH_ERR;
}
}
option=argv[2];
if (strcmp(option, "chkexpiry") == 0)
/* Check account information from the shadow file */
return _check_expiry(argv[1]);
/* read the nullok/nonull option */
else if (strcmp(option, "nullok") == 0)
nullok = 1;
else if (strcmp(option, "nonull") == 0)
nullok = 0;
else {
#ifdef HAVE_LIBAUDIT
_audit_log(AUDIT_ANOM_EXEC, getuidname(getuid()), PAM_SYSTEM_ERR);
#endif
return PAM_SYSTEM_ERR;
}
/* read the password from stdin (a pipe from the pam_unix module) */
npass = read_passwords(STDIN_FILENO, 1, passwords);
if (npass != 1) { /* is it a valid password? */
helper_log_err(LOG_DEBUG, "no password supplied");
*pass = '\0';
}
if (*pass == '\0') {
blankpass = 1;
}
retval = helper_verify_password(user, pass, nullok);
memset(pass, '\0', MAXPASS); /* clear memory of the password */
/* return pass or fail */
if (retval != PAM_SUCCESS) {
if (!nullok || !blankpass) {
/* no need to log blank pass test */
#ifdef HAVE_LIBAUDIT
if (getuid() != 0)
_audit_log(AUDIT_USER_AUTH, user, PAM_AUTH_ERR);
#endif
helper_log_err(LOG_NOTICE, "password check failed for user (%s)", user);
}
/* if helper_verify_password() returned PAM_USER_UNKNOWN, the
most appropriate error to propagate to
_unix_verify_password() is PAM_AUTHINFO_UNAVAIL; otherwise
return general failure */
if (retval == PAM_USER_UNKNOWN)
return PAM_AUTHINFO_UNAVAIL;
else
return PAM_AUTH_ERR;
} else {
if (getuid() != 0) {
#ifdef HAVE_LIBAUDIT
return _audit_log(AUDIT_USER_AUTH, user, PAM_SUCCESS);
#else
return PAM_SUCCESS;
#endif
}
return PAM_SUCCESS;
}
}
/*
* Copyright (c) Andrew G. Morgan, 1996. All rights reserved
* Copyright (c) Red Hat, Inc., 2007,2008. All rights reserved
*
* 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.
*/
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