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 #include <sys/procctl.h>
48
49 #include <ctype.h>
50 #include <err.h>
51 #include <grp.h>
52 #include <limits.h>
53 #include <paths.h>
54 #include <pwd.h>
55 #include <stdbool.h>
56 #include <stdio.h>
57 #include <stdlib.h>
58 #include <string.h>
59 #include <unistd.h>
60
61 static void usage(void);
62
63 int
main(int argc,char * argv[])64 main(int argc, char *argv[])
65 {
66 struct group *gp;
67 struct passwd *pw;
68 char *endp, *p, *user, *group, *grouplist;
69 const char *shell;
70 gid_t gid, *gidlist;
71 uid_t uid;
72 int arg, ch, error, gids;
73 long ngroups_max;
74 bool nonprivileged;
75
76 gid = 0;
77 uid = 0;
78 user = group = grouplist = NULL;
79 nonprivileged = false;
80 while ((ch = getopt(argc, argv, "G:g:u:n")) != -1) {
81 switch(ch) {
82 case 'u':
83 user = optarg;
84 if (*user == '\0')
85 usage();
86 break;
87 case 'g':
88 group = optarg;
89 if (*group == '\0')
90 usage();
91 break;
92 case 'G':
93 grouplist = optarg;
94 if (*grouplist == '\0')
95 usage();
96 break;
97 case 'n':
98 nonprivileged = true;
99 break;
100 case '?':
101 default:
102 usage();
103 }
104 }
105 argc -= optind;
106 argv += optind;
107
108 if (argc < 1)
109 usage();
110
111 if (group != NULL) {
112 if (isdigit((unsigned char)*group)) {
113 gid = (gid_t)strtoul(group, &endp, 0);
114 if (*endp != '\0')
115 goto getgroup;
116 } else {
117 getgroup:
118 if ((gp = getgrnam(group)) != NULL)
119 gid = gp->gr_gid;
120 else
121 errx(1, "no such group `%s'", group);
122 }
123 }
124
125 ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
126 if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
127 err(1, "malloc");
128 for (gids = 0;
129 (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) {
130 if (*p == '\0')
131 continue;
132
133 if (isdigit((unsigned char)*p)) {
134 gidlist[gids] = (gid_t)strtoul(p, &endp, 0);
135 if (*endp != '\0')
136 goto getglist;
137 } else {
138 getglist:
139 if ((gp = getgrnam(p)) != NULL)
140 gidlist[gids] = gp->gr_gid;
141 else
142 errx(1, "no such group `%s'", p);
143 }
144 gids++;
145 }
146 if (p != NULL && gids == ngroups_max)
147 errx(1, "too many supplementary groups provided");
148
149 if (user != NULL) {
150 if (isdigit((unsigned char)*user)) {
151 uid = (uid_t)strtoul(user, &endp, 0);
152 if (*endp != '\0')
153 goto getuser;
154 } else {
155 getuser:
156 if ((pw = getpwnam(user)) != NULL)
157 uid = pw->pw_uid;
158 else
159 errx(1, "no such user `%s'", user);
160 }
161 }
162
163 if (nonprivileged) {
164 arg = PROC_NO_NEW_PRIVS_ENABLE;
165 error = procctl(P_PID, getpid(), PROC_NO_NEW_PRIVS_CTL, &arg);
166 if (error != 0)
167 err(1, "procctl");
168 }
169
170 if (chdir(argv[0]) == -1 || chroot(".") == -1)
171 err(1, "%s", argv[0]);
172
173 if (gids && setgroups(gids, gidlist) == -1)
174 err(1, "setgroups");
175 if (group && setgid(gid) == -1)
176 err(1, "setgid");
177 if (user && setuid(uid) == -1)
178 err(1, "setuid");
179
180 if (argv[1]) {
181 execvp(argv[1], &argv[1]);
182 err(1, "%s", argv[1]);
183 }
184
185 if (!(shell = getenv("SHELL")))
186 shell = _PATH_BSHELL;
187 execlp(shell, shell, "-i", (char *)NULL);
188 err(1, "%s", shell);
189 /* NOTREACHED */
190 }
191
192 static void
usage(void)193 usage(void)
194 {
195 (void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] "
196 "[-u user] [-n] newroot [command]\n");
197 exit(1);
198 }
199