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 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if 0
31#ifndef lint
32static const char copyright[] =
33"@(#) Copyright (c) 1988, 1993\n\
34	The Regents of the University of California.  All rights reserved.\n";
35#endif /* not lint */
36
37#ifndef lint
38static char sccsid[] = "@(#)chroot.c	8.1 (Berkeley) 6/9/93";
39#endif /* not lint */
40#endif
41#include <sys/cdefs.h>
42__FBSDID("$FreeBSD$");
43
44#include <sys/types.h>
45
46#include <ctype.h>
47#include <err.h>
48#include <grp.h>
49#include <limits.h>
50#include <paths.h>
51#include <pwd.h>
52#include <stdio.h>
53#include <stdlib.h>
54#include <string.h>
55#include <unistd.h>
56
57static void usage(void);
58
59int
60main(int argc, char *argv[])
61{
62	struct group	*gp;
63	struct passwd	*pw;
64	char		*endp, *p, *user, *group, *grouplist;
65	const char	*shell;
66	gid_t		gid, *gidlist;
67	uid_t		uid;
68	int		ch, gids;
69	long		ngroups_max;
70
71	gid = 0;
72	uid = 0;
73	user = group = grouplist = NULL;
74	while ((ch = getopt(argc, argv, "G:g:u:")) != -1) {
75		switch(ch) {
76		case 'u':
77			user = optarg;
78			if (*user == '\0')
79				usage();
80			break;
81		case 'g':
82			group = optarg;
83			if (*group == '\0')
84				usage();
85			break;
86		case 'G':
87			grouplist = optarg;
88			if (*grouplist == '\0')
89				usage();
90			break;
91		case '?':
92		default:
93			usage();
94		}
95	}
96	argc -= optind;
97	argv += optind;
98
99	if (argc < 1)
100		usage();
101
102	if (group != NULL) {
103		if (isdigit((unsigned char)*group)) {
104			gid = (gid_t)strtoul(group, &endp, 0);
105			if (*endp != '\0')
106				goto getgroup;
107		} else {
108 getgroup:
109			if ((gp = getgrnam(group)) != NULL)
110				gid = gp->gr_gid;
111			else
112				errx(1, "no such group `%s'", group);
113		}
114	}
115
116	ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
117	if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
118		err(1, "malloc");
119	for (gids = 0;
120	    (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) {
121		if (*p == '\0')
122			continue;
123
124		if (isdigit((unsigned char)*p)) {
125			gidlist[gids] = (gid_t)strtoul(p, &endp, 0);
126			if (*endp != '\0')
127				goto getglist;
128		} else {
129 getglist:
130			if ((gp = getgrnam(p)) != NULL)
131				gidlist[gids] = gp->gr_gid;
132			else
133				errx(1, "no such group `%s'", p);
134		}
135		gids++;
136	}
137	if (p != NULL && gids == ngroups_max)
138		errx(1, "too many supplementary groups provided");
139
140	if (user != NULL) {
141		if (isdigit((unsigned char)*user)) {
142			uid = (uid_t)strtoul(user, &endp, 0);
143			if (*endp != '\0')
144				goto getuser;
145		} else {
146 getuser:
147			if ((pw = getpwnam(user)) != NULL)
148				uid = pw->pw_uid;
149			else
150				errx(1, "no such user `%s'", user);
151		}
152	}
153
154	if (chdir(argv[0]) == -1 || chroot(".") == -1)
155		err(1, "%s", argv[0]);
156
157	if (gids && setgroups(gids, gidlist) == -1)
158		err(1, "setgroups");
159	if (group && setgid(gid) == -1)
160		err(1, "setgid");
161	if (user && setuid(uid) == -1)
162		err(1, "setuid");
163
164	if (argv[1]) {
165		execvp(argv[1], &argv[1]);
166		err(1, "%s", argv[1]);
167	}
168
169	if (!(shell = getenv("SHELL")))
170		shell = _PATH_BSHELL;
171	execlp(shell, shell, "-i", (char *)NULL);
172	err(1, "%s", shell);
173	/* NOTREACHED */
174}
175
176static void
177usage(void)
178{
179	(void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] "
180	    "[-u user] newroot [command]\n");
181	exit(1);
182}
183