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 #include <sys/types.h>
45 #include <sys/procctl.h>
46
47 #include <ctype.h>
48 #include <err.h>
49 #include <grp.h>
50 #include <limits.h>
51 #include <paths.h>
52 #include <pwd.h>
53 #include <stdbool.h>
54 #include <stdio.h>
55 #include <stdlib.h>
56 #include <string.h>
57 #include <unistd.h>
58
59 static void usage(void) __dead2;
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 arg, ch, error, gids;
71 long ngroups_max;
72 bool nonprivileged;
73
74 gid = 0;
75 uid = 0;
76 user = group = grouplist = NULL;
77 nonprivileged = false;
78 while ((ch = getopt(argc, argv, "G:g:u:n")) != -1) {
79 switch(ch) {
80 case 'u':
81 user = optarg;
82 if (*user == '\0')
83 usage();
84 break;
85 case 'g':
86 group = optarg;
87 if (*group == '\0')
88 usage();
89 break;
90 case 'G':
91 grouplist = optarg;
92 if (*grouplist == '\0')
93 usage();
94 break;
95 case 'n':
96 nonprivileged = true;
97 break;
98 case '?':
99 default:
100 usage();
101 }
102 }
103 argc -= optind;
104 argv += optind;
105
106 if (argc < 1)
107 usage();
108
109 if (group != NULL) {
110 if (isdigit((unsigned char)*group)) {
111 gid = (gid_t)strtoul(group, &endp, 0);
112 if (*endp != '\0')
113 goto getgroup;
114 } else {
115 getgroup:
116 if ((gp = getgrnam(group)) != NULL)
117 gid = gp->gr_gid;
118 else
119 errx(1, "no such group `%s'", group);
120 }
121 }
122
123 ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
124 if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
125 err(1, "malloc");
126 for (gids = 0;
127 (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) {
128 if (*p == '\0')
129 continue;
130
131 if (isdigit((unsigned char)*p)) {
132 gidlist[gids] = (gid_t)strtoul(p, &endp, 0);
133 if (*endp != '\0')
134 goto getglist;
135 } else {
136 getglist:
137 if ((gp = getgrnam(p)) != NULL)
138 gidlist[gids] = gp->gr_gid;
139 else
140 errx(1, "no such group `%s'", p);
141 }
142 gids++;
143 }
144 if (p != NULL && gids == ngroups_max)
145 errx(1, "too many supplementary groups provided");
146
147 if (user != NULL) {
148 if (isdigit((unsigned char)*user)) {
149 uid = (uid_t)strtoul(user, &endp, 0);
150 if (*endp != '\0')
151 goto getuser;
152 } else {
153 getuser:
154 if ((pw = getpwnam(user)) != NULL)
155 uid = pw->pw_uid;
156 else
157 errx(1, "no such user `%s'", user);
158 }
159 }
160
161 if (nonprivileged) {
162 arg = PROC_NO_NEW_PRIVS_ENABLE;
163 error = procctl(P_PID, getpid(), PROC_NO_NEW_PRIVS_CTL, &arg);
164 if (error != 0)
165 err(1, "procctl");
166 }
167
168 if (chdir(argv[0]) == -1 || chroot(".") == -1)
169 err(1, "%s", argv[0]);
170
171 if (gids && setgroups(gids, gidlist) == -1)
172 err(1, "setgroups");
173 if (group && setgid(gid) == -1)
174 err(1, "setgid");
175 if (user && setuid(uid) == -1)
176 err(1, "setuid");
177
178 if (argv[1]) {
179 execvp(argv[1], &argv[1]);
180 err(1, "%s", argv[1]);
181 }
182
183 if (!(shell = getenv("SHELL")))
184 shell = _PATH_BSHELL;
185 execlp(shell, shell, "-i", (char *)NULL);
186 err(1, "%s", shell);
187 /* NOTREACHED */
188 }
189
190 static void
usage(void)191 usage(void)
192 {
193 (void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] "
194 "[-u user] [-n] newroot [command]\n");
195 exit(1);
196 }
197