2 * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
3 * Copyright (c) 2004-2007 Dag-Erling Smørgrav
6 * This software was developed for the FreeBSD Project by ThinkSec AS and
7 * Network Associates Laboratories, the Security Research Division of
8 * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035
9 * ("CBOSS"), as part of the DARPA CHATS research program.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote
20 * products derived from this software without specific prior written
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * $Id: su.c 408 2007-12-21 11:36:24Z des $
38 #include <sys/param.h>
50 #include <security/pam_appl.h>
51 #include <security/openpam.h> /* for openpam_ttyconv() */
53 extern char **environ;
55 static pam_handle_t *pamh;
56 static struct pam_conv pamc;
62 fprintf(stderr, "Usage: su [login [args]]\n");
67 main(int argc, char *argv[])
69 char hostname[MAXHOSTNAMELEN];
70 const char *user, *tty;
72 char **args, **pam_envlist, **pam_env;
74 int o, pam_err, status;
77 while ((o = getopt(argc, argv, "h")) != -1)
96 pamc.conv = &openpam_ttyconv;
97 pam_start("su", user, &pamc, &pamh);
100 gethostname(hostname, sizeof(hostname));
101 if ((pam_err = pam_set_item(pamh, PAM_RHOST, hostname)) != PAM_SUCCESS)
104 if ((pam_err = pam_set_item(pamh, PAM_RUSER, user)) != PAM_SUCCESS)
106 tty = ttyname(STDERR_FILENO);
107 if ((pam_err = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS)
110 /* authenticate the applicant */
111 if ((pam_err = pam_authenticate(pamh, 0)) != PAM_SUCCESS)
113 if ((pam_err = pam_acct_mgmt(pamh, 0)) == PAM_NEW_AUTHTOK_REQD)
114 pam_err = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
115 if (pam_err != PAM_SUCCESS)
118 /* establish the requested credentials */
119 if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED)) != PAM_SUCCESS)
122 /* authentication succeeded; open a session */
123 if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS)
126 /* get mapped user name; PAM may have changed it */
127 pam_err = pam_get_item(pamh, PAM_USER, &item);
128 if (pam_err != PAM_SUCCESS || (pwd = getpwnam(user = item)) == NULL)
131 /* export PAM environment */
132 if ((pam_envlist = pam_getenvlist(pamh)) != NULL) {
133 for (pam_env = pam_envlist; *pam_env != NULL; ++pam_env) {
140 /* build argument list */
141 if ((args = calloc(argc + 2, sizeof *args)) == NULL) {
145 *args = pwd->pw_shell;
146 memcpy(args + 1, argv, argc * sizeof *args);
149 switch ((pid = fork())) {
154 /* child: give up privs and start a shell */
156 /* set uid and groups */
157 if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
158 warn("initgroups()");
161 if (setgid(pwd->pw_gid) == -1) {
165 if (setuid(pwd->pw_uid) == -1) {
169 execve(*args, args, environ);
173 /* parent: wait for child to exit */
174 waitpid(pid, &status, 0);
176 /* close the session and release PAM resources */
177 pam_err = pam_close_session(pamh, 0);
178 pam_end(pamh, pam_err);
180 exit(WEXITSTATUS(status));
184 fprintf(stderr, "Sorry\n");
186 pam_end(pamh, pam_err);