1 /* 2 * Copyright (c) 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if 0 31 #ifndef lint 32 static const char copyright[] = 33 "@(#) Copyright (c) 1988, 1993\n\ 34 The Regents of the University of California. All rights reserved.\n"; 35 #endif /* not lint */ 36 37 #ifndef lint 38 static char sccsid[] = "@(#)chroot.c 8.1 (Berkeley) 6/9/93"; 39 #endif /* not lint */ 40 #endif 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/types.h> 45 46 #include <ctype.h> 47 #include <err.h> 48 #include <grp.h> 49 #include <limits.h> 50 #include <paths.h> 51 #include <pwd.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 static void usage(void); 58 59 char *user; /* user to switch to before running program */ 60 char *group; /* group to switch to ... */ 61 char *grouplist; /* group list to switch to ... */ 62 63 int 64 main(argc, argv) 65 int argc; 66 char *argv[]; 67 { 68 struct group *gp; 69 struct passwd *pw; 70 char *endp, *p; 71 const char *shell; 72 gid_t gid, *gidlist; 73 uid_t uid; 74 int ch, gids; 75 long ngroups_max; 76 77 gid = 0; 78 uid = 0; 79 while ((ch = getopt(argc, argv, "G:g:u:")) != -1) { 80 switch(ch) { 81 case 'u': 82 user = optarg; 83 if (*user == '\0') 84 usage(); 85 break; 86 case 'g': 87 group = optarg; 88 if (*group == '\0') 89 usage(); 90 break; 91 case 'G': 92 grouplist = optarg; 93 if (*grouplist == '\0') 94 usage(); 95 break; 96 case '?': 97 default: 98 usage(); 99 } 100 } 101 argc -= optind; 102 argv += optind; 103 104 if (argc < 1) 105 usage(); 106 107 if (group != NULL) { 108 if (isdigit((unsigned char)*group)) { 109 gid = (gid_t)strtoul(group, &endp, 0); 110 if (*endp != '\0') 111 goto getgroup; 112 } else { 113 getgroup: 114 if ((gp = getgrnam(group)) != NULL) 115 gid = gp->gr_gid; 116 else 117 errx(1, "no such group `%s'", group); 118 } 119 } 120 121 ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1; 122 if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL) 123 err(1, "malloc"); 124 for (gids = 0; 125 (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) { 126 if (*p == '\0') 127 continue; 128 129 if (isdigit((unsigned char)*p)) { 130 gidlist[gids] = (gid_t)strtoul(p, &endp, 0); 131 if (*endp != '\0') 132 goto getglist; 133 } else { 134 getglist: 135 if ((gp = getgrnam(p)) != NULL) 136 gidlist[gids] = gp->gr_gid; 137 else 138 errx(1, "no such group `%s'", p); 139 } 140 gids++; 141 } 142 if (p != NULL && gids == ngroups_max) 143 errx(1, "too many supplementary groups provided"); 144 145 if (user != NULL) { 146 if (isdigit((unsigned char)*user)) { 147 uid = (uid_t)strtoul(user, &endp, 0); 148 if (*endp != '\0') 149 goto getuser; 150 } else { 151 getuser: 152 if ((pw = getpwnam(user)) != NULL) 153 uid = pw->pw_uid; 154 else 155 errx(1, "no such user `%s'", user); 156 } 157 } 158 159 if (chdir(argv[0]) == -1 || chroot(".") == -1) 160 err(1, "%s", argv[0]); 161 162 if (gids && setgroups(gids, gidlist) == -1) 163 err(1, "setgroups"); 164 if (group && setgid(gid) == -1) 165 err(1, "setgid"); 166 if (user && setuid(uid) == -1) 167 err(1, "setuid"); 168 169 if (argv[1]) { 170 execvp(argv[1], &argv[1]); 171 err(1, "%s", argv[1]); 172 } 173 174 if (!(shell = getenv("SHELL"))) 175 shell = _PATH_BSHELL; 176 execlp(shell, shell, "-i", (char *)NULL); 177 err(1, "%s", shell); 178 /* NOTREACHED */ 179 } 180 181 static void 182 usage() 183 { 184 (void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] " 185 "[-u user] newroot [command]\n"); 186 exit(1); 187 } 188