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 #include <sys/types.h>
33 #include <sys/procctl.h>
34
35 #include <ctype.h>
36 #include <err.h>
37 #include <grp.h>
38 #include <limits.h>
39 #include <paths.h>
40 #include <pwd.h>
41 #include <stdbool.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46
47 static void usage(void) __dead2;
48
49 int
main(int argc,char * argv[])50 main(int argc, char *argv[])
51 {
52 struct group *gp;
53 struct passwd *pw;
54 char *endp, *p, *user, *group, *grouplist;
55 const char *shell;
56 gid_t gid, *gidlist;
57 uid_t uid;
58 int arg, ch, error, gids;
59 long ngroups_max;
60 bool nonprivileged;
61
62 gid = 0;
63 uid = 0;
64 user = group = grouplist = NULL;
65 nonprivileged = false;
66 while ((ch = getopt(argc, argv, "G:g:u:n")) != -1) {
67 switch(ch) {
68 case 'u':
69 user = optarg;
70 if (*user == '\0')
71 usage();
72 break;
73 case 'g':
74 group = optarg;
75 if (*group == '\0')
76 usage();
77 break;
78 case 'G':
79 grouplist = optarg;
80 if (*grouplist == '\0')
81 usage();
82 break;
83 case 'n':
84 nonprivileged = true;
85 break;
86 case '?':
87 default:
88 usage();
89 }
90 }
91 argc -= optind;
92 argv += optind;
93
94 if (argc < 1)
95 usage();
96
97 if (group != NULL) {
98 if (isdigit((unsigned char)*group)) {
99 gid = (gid_t)strtoul(group, &endp, 0);
100 if (*endp != '\0')
101 goto getgroup;
102 } else {
103 getgroup:
104 if ((gp = getgrnam(group)) != NULL)
105 gid = gp->gr_gid;
106 else
107 errx(1, "no such group `%s'", group);
108 }
109 }
110
111 ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1;
112 if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL)
113 err(1, "malloc");
114 for (gids = 0;
115 (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) {
116 if (*p == '\0')
117 continue;
118
119 if (isdigit((unsigned char)*p)) {
120 gidlist[gids] = (gid_t)strtoul(p, &endp, 0);
121 if (*endp != '\0')
122 goto getglist;
123 } else {
124 getglist:
125 if ((gp = getgrnam(p)) != NULL)
126 gidlist[gids] = gp->gr_gid;
127 else
128 errx(1, "no such group `%s'", p);
129 }
130 gids++;
131 }
132 if (p != NULL && gids == ngroups_max)
133 errx(1, "too many supplementary groups provided");
134
135 if (user != NULL) {
136 if (isdigit((unsigned char)*user)) {
137 uid = (uid_t)strtoul(user, &endp, 0);
138 if (*endp != '\0')
139 goto getuser;
140 } else {
141 getuser:
142 if ((pw = getpwnam(user)) != NULL)
143 uid = pw->pw_uid;
144 else
145 errx(1, "no such user `%s'", user);
146 }
147 }
148
149 if (nonprivileged) {
150 arg = PROC_NO_NEW_PRIVS_ENABLE;
151 error = procctl(P_PID, getpid(), PROC_NO_NEW_PRIVS_CTL, &arg);
152 if (error != 0)
153 err(1, "procctl");
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] [-n] newroot [command]\n");
183 exit(1);
184 }
185