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 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 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