1 /* vi: set sw=4 ts=4: */
2 /*
3 * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of Julianne F. Haugh nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ''AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30 #include "libbb.h"
31
32 /* Become the user and group(s) specified by PW. */
change_identity(const struct passwd * pw)33 void FAST_FUNC change_identity(const struct passwd *pw)
34 {
35 int res;
36
37 res = initgroups(pw->pw_name, pw->pw_gid);
38 endgrent(); /* helps to close a fd used internally by libc */
39
40 if (res != 0) {
41 /*
42 * If initgroups() fails because a system call is unimplemented
43 * then we are running on a Linux kernel compiled without multiuser
44 * support (CONFIG_MULTIUSER is not defined).
45 *
46 * If we are running without multiuser support *and* the target uid
47 * already matches the current uid then we can skip the change of
48 * identity.
49 */
50 if (errno == ENOSYS && pw->pw_uid == getuid()) {
51 return;
52 }
53
54 bb_simple_perror_msg_and_die("can't set groups");
55 }
56
57 xsetgid(pw->pw_gid);
58 xsetuid(pw->pw_uid);
59 }
60