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 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 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