1/*
2 * Copyright (c) 1988, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35#ifndef lint
36__COPYRIGHT("@(#) Copyright (c) 1988, 1993\n\
37	The Regents of the University of California.  All rights reserved.\n");
38#endif /* not lint */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)chroot.c	8.1 (Berkeley) 6/9/93";
43#else
44__RCSID("$NetBSD: chroot.c,v 1.7 1998/10/06 03:47:51 mrg Exp $");
45#endif
46#endif /* not lint */
47
48#include <sys/param.h>
49
50#include <ctype.h>
51#include <err.h>
52#include <errno.h>
53#include <grp.h>
54#include <paths.h>
55#include <pwd.h>
56#include <stdio.h>
57#include <stdlib.h>
58#include <string.h>
59#include <unistd.h>
60
61int	main __P((int, char **));
62void	usage __P((void)) __attribute__((__noreturn__));
63
64char	*user;		/* user to switch to before running program */
65char	*group;		/* group to switch to ... */
66char	*grouplist;	/* group list to switch to ... */
67
68int
69main(argc, argv)
70	int argc;
71	char *argv[];
72{
73	struct group *gp;
74	struct passwd *pw;
75	char *shell, *endp, *comma;
76	gid_t gid = 0, gidlist[NGROUPS_MAX];
77	uid_t uid = 0;
78	int ch, gids;
79
80	while ((ch = getopt(argc, argv, "G:g:u:")) != -1)
81		switch(ch) {
82		case 'u':
83			user = optarg;
84			break;
85		case 'g':
86			group = optarg;
87			break;
88		case 'G':
89			grouplist = optarg;
90			break;
91		case '?':
92		default:
93			usage();
94		}
95	argc -= optind;
96	argv += optind;
97
98	if (argc < 1)
99		usage();
100
101	if (group) {
102		if (isdigit(*group)) {
103			gid = (gid_t)strtol(group, &endp, 0);
104			if (endp == group)
105				goto getgroup;
106		} else {
107getgroup:
108			if ((gp = getgrnam(group)))
109				gid = gp->gr_gid;
110			else
111				errx(1, "no such group %s", group);
112		}
113	}
114
115	for (gids = 0; grouplist; ) {
116		comma = strchr(grouplist, ',');
117
118		if (comma)
119			*comma++ = '\0';
120
121		if (isdigit(*grouplist)) {
122			gidlist[gids] = (gid_t)strtol(grouplist, &endp, 0);
123			if (endp == grouplist)
124				goto getglist;
125		} else {
126getglist:
127			if ((gp = getgrnam(grouplist)))
128				gidlist[gids] = gp->gr_gid;
129			else
130				errx(1, "no such group %s", group);
131		}
132		gids++;
133		grouplist = comma;
134	}
135
136	if (user) {
137		if (isdigit(*user)) {
138			uid = (uid_t)strtol(user, &endp, 0);
139			if (endp == user)
140				goto getuser;
141		} else {
142getuser:
143			if ((pw = getpwnam(user)))
144				uid = pw->pw_uid;
145			else
146				errx(1, "no such user %s", user);
147		}
148	}
149
150	if (chdir(argv[0]) || chroot("."))
151		err(1, "%s", argv[0]);
152
153	if (gids && setgroups(gids, gidlist) < 0)
154		err(1, "setgroups");
155	if (group && setgid(gid) < 0)
156		err(1, "setgid");
157	if (user && setuid(uid) < 0)
158		err(1, "setuid");
159
160	if (argv[1]) {
161		execvp(argv[1], &argv[1]);
162		err(1, "%s", argv[1]);
163	}
164
165	if (!(shell = getenv("SHELL")))
166		shell = _PATH_BSHELL;
167	execlp(shell, shell, "-i", NULL);
168	err(1, "%s", shell);
169	/* NOTREACHED */
170}
171
172void
173usage()
174{
175	(void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] "
176	    "[-u user] newroot [command]\n");
177	exit(1);
178}
179