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/*-
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by ThinkSec AS and
* NAI Labs, the Security Research Division of Network Associates, Inc.
* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
* DARPA CHATS research program.
*
* 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, this list of conditions and the following disclaimer.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
*
* $P4: //depot/projects/openpam/bin/su/su.c#5 $
*/
#include <sys/param.h>
#include <sys/wait.h>
#include <err.h>
#include <pwd.h>
#include <stdio.h>
#include <syslog.h>
#include <unistd.h>
#include <security/pam_appl.h>
#include <security/openpam.h>
static pam_handle_t *pamh;
static struct pam_conv pamc;
static void
usage(void)
{
fprintf(stderr, "Usage: su [login [args]]\n");
exit(1);
}
static int
check(const char *func, int pam_err)
{
if (pam_err == PAM_SUCCESS || pam_err == PAM_NEW_AUTHTOK_REQD)
return pam_err;
openlog("su", LOG_CONS, LOG_AUTH);
syslog(LOG_ERR, "%s(): %s", func, pam_strerror(pamh, pam_err));
errx(1, "Sorry.");
}
int
main(int argc, char *argv[])
{
char hostname[MAXHOSTNAMELEN];
const char *user, *tty;
struct passwd *pwd;
int o, status;
pid_t pid;
while ((o = getopt(argc, argv, "h")) != -1)
switch (o) {
case 'h':
default:
usage();
}
argc -= optind;
argv += optind;
/* initialize PAM */
pamc.conv = &openpam_ttyconv;
pam_start("su", argc ? *argv : "root", &pamc, &pamh);
/* set some items */
gethostname(hostname, sizeof(hostname));
check("pam_set_item", pam_set_item(pamh, PAM_RHOST, hostname));
user = getlogin();
check("pam_set_item", pam_set_item(pamh, PAM_RUSER, user));
tty = ttyname(STDERR_FILENO);
check("pam_set_item", pam_set_item(pamh, PAM_TTY, tty));
/* authenticate the applicant */
check("pam_authenticate", pam_authenticate(pamh, 0));
if (check("pam_acct_mgmt", pam_acct_mgmt(pamh, 0)) ==
PAM_NEW_AUTHTOK_REQD)
check("pam_chauthtok",
pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK));
/* establish the requested credentials */
check("pam_setcred", pam_setcred(pamh, PAM_ESTABLISH_CRED));
/* authentication succeeded; open a session */
check("pam_open_session", pam_open_session(pamh, 0));
if (initgroups(pwd->pw_name, pwd->pw_gid) == -1)
err(1, "initgroups()");
if (setuid(pwd->pw_uid) == -1)
err(1, "setuid()");
/* XXX export environment variables */
switch ((pid = fork())) {
case -1:
err(1, "fork()");
case 0:
/* child: start a shell */
*argv = pwd->pw_shell;
execvp(*argv, argv);
err(1, "execvp()");
default:
/* parent: wait for child to exit */
waitpid(pid, &status, 0);
if (WIFEXITED(status))
status = WEXITSTATUS(status);
else
status = 1;
}
/* close the session and release PAM resources */
check("pam_close_session", pam_close_session(pamh, 0));
check("pam_end", pam_end(pamh, 0));
exit(status);
}
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