1 /* $OpenBSD: chroot.c,v 1.12 2005/05/23 22:52:04 henning Exp $ */ 2 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 #ifndef lint 33 static const char copyright[] = 34 "@(#) Copyright (c) 1988, 1993\n\ 35 The Regents of the University of California. All rights reserved.\n"; 36 #endif /* not lint */ 37 38 #ifndef lint 39 #if 0 40 static const char sccsid[] = "@(#)chroot.c 8.1 (Berkeley) 6/9/93"; 41 #else 42 static const char rcsid[] = "$OpenBSD: chroot.c,v 1.12 2005/05/23 22:52:04 henning Exp $"; 43 #endif 44 #endif /* not lint */ 45 46 #include <sys/types.h> 47 #include <ctype.h> 48 #include <err.h> 49 #include <errno.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 int main(int, char **); 60 __dead void usage(void); 61 62 int 63 main(int argc, char **argv) 64 { 65 struct group *grp; 66 struct passwd *pwd; 67 const char *shell; 68 char *user, *group, *grouplist; 69 gid_t gidlist[NGROUPS_MAX]; 70 int ch, ngids; 71 72 ngids = 0; 73 pwd = NULL; 74 user = grouplist = NULL; 75 while ((ch = getopt(argc, argv, "g:u:")) != -1) { 76 switch(ch) { 77 case 'u': 78 user = optarg; 79 if (*user == '\0') 80 usage(); 81 break; 82 case 'g': 83 grouplist = optarg; 84 if (*grouplist == '\0') 85 usage(); 86 break; 87 default: 88 usage(); 89 } 90 } 91 argc -= optind; 92 argv += optind; 93 94 if (argc < 1) 95 usage(); 96 97 if (user != NULL && (pwd = getpwnam(user)) == NULL) 98 errx(1, "no such user `%s'", user); 99 100 while ((group = strsep(&grouplist, ",")) != NULL) { 101 if (*group == '\0') 102 continue; 103 104 if (ngids == NGROUPS_MAX) 105 errx(1, "too many supplementary groups provided"); 106 if ((grp = getgrnam(group)) == NULL) 107 errx(1, "no such group `%s'", group); 108 gidlist[ngids++] = grp->gr_gid; 109 } 110 111 if (ngids != 0) { 112 if (setgid(gidlist[0]) != 0) 113 err(1, "setgid"); 114 if (setgroups(ngids, gidlist) != 0) 115 err(1, "setgroups"); 116 } else if (pwd != NULL) { 117 if (setgid(pwd->pw_gid) != 0) 118 err(1, "setgid"); 119 if (initgroups(user, pwd->pw_gid) == -1) 120 err(1, "initgroups"); 121 } 122 123 if (chroot(argv[0]) != 0 || chdir("/") != 0) 124 err(1, "%s", argv[0]); 125 126 if (pwd != NULL) { 127 /* only set login name if we are/can be a session leader */ 128 if (getsid(0) == getpid() || setsid() != -1) 129 setlogin(pwd->pw_name); 130 if (setuid(pwd->pw_uid) != 0) 131 err(1, "setuid"); 132 endgrent(); 133 } 134 135 if (argv[1]) { 136 execvp(argv[1], &argv[1]); 137 err(1, "%s", argv[1]); 138 } 139 140 if ((shell = getenv("SHELL")) == NULL || *shell == '\0') 141 shell = _PATH_BSHELL; 142 execlp(shell, shell, "-i", (char *)NULL); 143 err(1, "%s", shell); 144 /* NOTREACHED */ 145 } 146 147 __dead void 148 usage(void) 149 { 150 extern char *__progname; 151 152 (void)fprintf(stderr, "usage: %s [-g group,group,...] [-u user] " 153 "newroot [command]\n", __progname); 154 exit(1); 155 } 156