1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1988, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #if 0
33 #ifndef lint
34 static const char copyright[] =
35 "@(#) Copyright (c) 1988, 1993\n\
36 The Regents of the University of California. All rights reserved.\n";
37 #endif /* not lint */
38
39 #ifndef lint
40 static char sccsid[] = "@(#)chroot.c 8.1 (Berkeley) 6/9/93";
41 #endif /* not lint */
42 #endif
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45
46 #include <sys/types.h>
47
48 #include <ctype.h>
49 #include <err.h>
50 #include <grp.h>
51 #include <limits.h>
52 #include <paths.h>
53 #include <pwd.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58
59 static void usage(void);
60
61 int
main(int argc,char * argv[])62 main(int argc, char *argv[])
63 {
64 struct group *gp;
65 struct passwd *pw;
66 char *endp, *p, *user, *group, *grouplist;
67 const char *shell;
68 gid_t gid, *gidlist;
69 uid_t uid;
70 int ch, gids;
71 long ngroups_max;
72
73 gid = 0;
74 uid = 0;
75 user = group = grouplist = NULL;
76 while ((ch = getopt(argc, argv, "G:g:u:")) != -1) {
77 switch(ch) {
78 case 'u':
79 user = optarg;
80 if (*user == '\0')
81 usage();
82 break;
83 case 'g':
84 group = optarg;
85 if (*group == '\0')
86 usage();
87 break;
88 case 'G':
89 grouplist = optarg;
90 if (*grouplist == '\0')
91 usage();
92 break;
93 case '?':
94 default:
95 usage();
96 }
97 }
98 argc -= optind;
99 argv += optind;
100
101 if (argc < 1)
102 usage();
103
104 if (group != NULL) {
105 if (isdigit((unsigned char)*group)) {
106 gid = (gid_t)strtoul(group, &endp, 0);
107 if (*endp != '\0')
108 goto getgroup;
109 } else {
110 getgroup:
111 if ((gp = getgrnam(group)) != NULL)
112 gid = gp->gr_gid;
113 else
114 errx(1, "no such group `%s'", group);
115 }
116 }
117
118 ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
119 if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
120 err(1, "malloc");
121 for (gids = 0;
122 (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) {
123 if (*p == '\0')
124 continue;
125
126 if (isdigit((unsigned char)*p)) {
127 gidlist[gids] = (gid_t)strtoul(p, &endp, 0);
128 if (*endp != '\0')
129 goto getglist;
130 } else {
131 getglist:
132 if ((gp = getgrnam(p)) != NULL)
133 gidlist[gids] = gp->gr_gid;
134 else
135 errx(1, "no such group `%s'", p);
136 }
137 gids++;
138 }
139 if (p != NULL && gids == ngroups_max)
140 errx(1, "too many supplementary groups provided");
141
142 if (user != NULL) {
143 if (isdigit((unsigned char)*user)) {
144 uid = (uid_t)strtoul(user, &endp, 0);
145 if (*endp != '\0')
146 goto getuser;
147 } else {
148 getuser:
149 if ((pw = getpwnam(user)) != NULL)
150 uid = pw->pw_uid;
151 else
152 errx(1, "no such user `%s'", user);
153 }
154 }
155
156 if (chdir(argv[0]) == -1 || chroot(".") == -1)
157 err(1, "%s", argv[0]);
158
159 if (gids && setgroups(gids, gidlist) == -1)
160 err(1, "setgroups");
161 if (group && setgid(gid) == -1)
162 err(1, "setgid");
163 if (user && setuid(uid) == -1)
164 err(1, "setuid");
165
166 if (argv[1]) {
167 execvp(argv[1], &argv[1]);
168 err(1, "%s", argv[1]);
169 }
170
171 if (!(shell = getenv("SHELL")))
172 shell = _PATH_BSHELL;
173 execlp(shell, shell, "-i", (char *)NULL);
174 err(1, "%s", shell);
175 /* NOTREACHED */
176 }
177
178 static void
usage(void)179 usage(void)
180 {
181 (void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] "
182 "[-u user] newroot [command]\n");
183 exit(1);
184 }
185