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(int argc, char *argv[]) 65 { 66 struct group *gp; 67 struct passwd *pw; 68 char *endp, *p; 69 const char *shell; 70 gid_t gid, *gidlist; 71 uid_t uid; 72 int ch, gids; 73 long ngroups_max; 74 75 gid = 0; 76 uid = 0; 77 while ((ch = getopt(argc, argv, "G:g:u:")) != -1) { 78 switch(ch) { 79 case 'u': 80 user = optarg; 81 if (*user == '\0') 82 usage(); 83 break; 84 case 'g': 85 group = optarg; 86 if (*group == '\0') 87 usage(); 88 break; 89 case 'G': 90 grouplist = optarg; 91 if (*grouplist == '\0') 92 usage(); 93 break; 94 case '?': 95 default: 96 usage(); 97 } 98 } 99 argc -= optind; 100 argv += optind; 101 102 if (argc < 1) 103 usage(); 104 105 if (group != NULL) { 106 if (isdigit((unsigned char)*group)) { 107 gid = (gid_t)strtoul(group, &endp, 0); 108 if (*endp != '\0') 109 goto getgroup; 110 } else { 111 getgroup: 112 if ((gp = getgrnam(group)) != NULL) 113 gid = gp->gr_gid; 114 else 115 errx(1, "no such group `%s'", group); 116 } 117 } 118 119 ngroups_max = sysconf(_SC_NGROUPS_MAX) + 1; 120 if ((gidlist = malloc(sizeof(gid_t) * ngroups_max)) == NULL) 121 err(1, "malloc"); 122 for (gids = 0; 123 (p = strsep(&grouplist, ",")) != NULL && gids < ngroups_max; ) { 124 if (*p == '\0') 125 continue; 126 127 if (isdigit((unsigned char)*p)) { 128 gidlist[gids] = (gid_t)strtoul(p, &endp, 0); 129 if (*endp != '\0') 130 goto getglist; 131 } else { 132 getglist: 133 if ((gp = getgrnam(p)) != NULL) 134 gidlist[gids] = gp->gr_gid; 135 else 136 errx(1, "no such group `%s'", p); 137 } 138 gids++; 139 } 140 if (p != NULL && gids == ngroups_max) 141 errx(1, "too many supplementary groups provided"); 142 143 if (user != NULL) { 144 if (isdigit((unsigned char)*user)) { 145 uid = (uid_t)strtoul(user, &endp, 0); 146 if (*endp != '\0') 147 goto getuser; 148 } else { 149 getuser: 150 if ((pw = getpwnam(user)) != NULL) 151 uid = pw->pw_uid; 152 else 153 errx(1, "no such user `%s'", user); 154 } 155 } 156 157 if (chdir(argv[0]) == -1 || chroot(".") == -1) 158 err(1, "%s", argv[0]); 159 160 if (gids && setgroups(gids, gidlist) == -1) 161 err(1, "setgroups"); 162 if (group && setgid(gid) == -1) 163 err(1, "setgid"); 164 if (user && setuid(uid) == -1) 165 err(1, "setuid"); 166 167 if (argv[1]) { 168 execvp(argv[1], &argv[1]); 169 err(1, "%s", argv[1]); 170 } 171 172 if (!(shell = getenv("SHELL"))) 173 shell = _PATH_BSHELL; 174 execlp(shell, shell, "-i", (char *)NULL); 175 err(1, "%s", shell); 176 /* NOTREACHED */ 177 } 178 179 static void 180 usage(void) 181 { 182 (void)fprintf(stderr, "usage: chroot [-g group] [-G group,group,...] " 183 "[-u user] newroot [command]\n"); 184 exit(1); 185 } 186