1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org> 5 * Copyright (c) 2008 Bjoern A. Zeeb <bz@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 * $FreeBSD$ 30 */ 31 32 #include <sys/param.h> 33 #include <sys/jail.h> 34 #include <sys/socket.h> 35 #include <sys/sysctl.h> 36 37 #include <arpa/inet.h> 38 #include <netinet/in.h> 39 40 #include <err.h> 41 #include <errno.h> 42 #include <jail.h> 43 #include <limits.h> 44 #include <login_cap.h> 45 #include <paths.h> 46 #include <pwd.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 52 extern char **environ; 53 54 static void get_user_info(const char *username, const struct passwd **pwdp, 55 login_cap_t **lcapp); 56 static void usage(void); 57 58 int 59 main(int argc, char *argv[]) 60 { 61 int jid; 62 login_cap_t *lcap = NULL; 63 int ch, clean, uflag, Uflag; 64 char *cleanenv; 65 const struct passwd *pwd = NULL; 66 const char *username, *shell, *term; 67 68 ch = clean = uflag = Uflag = 0; 69 username = NULL; 70 71 while ((ch = getopt(argc, argv, "lnu:U:")) != -1) { 72 switch (ch) { 73 case 'l': 74 clean = 1; 75 break; 76 case 'n': 77 /* Specified name, now unused */ 78 break; 79 case 'u': 80 username = optarg; 81 uflag = 1; 82 break; 83 case 'U': 84 username = optarg; 85 Uflag = 1; 86 break; 87 default: 88 usage(); 89 } 90 } 91 argc -= optind; 92 argv += optind; 93 if (argc < 1) 94 usage(); 95 if (uflag && Uflag) 96 usage(); 97 if (uflag || (clean && !Uflag)) 98 /* User info from the home environment */ 99 get_user_info(username, &pwd, &lcap); 100 101 /* Attach to the jail */ 102 jid = jail_getid(argv[0]); 103 if (jid < 0) 104 errx(1, "%s", jail_errmsg); 105 if (jail_attach(jid) == -1) 106 err(1, "jail_attach(%d)", jid); 107 if (chdir("/") == -1) 108 err(1, "chdir(): /"); 109 110 /* Set up user environment */ 111 if (clean || username != NULL) { 112 if (Uflag) 113 /* User info from the jail environment */ 114 get_user_info(username, &pwd, &lcap); 115 if (clean) { 116 term = getenv("TERM"); 117 cleanenv = NULL; 118 environ = &cleanenv; 119 setenv("PATH", "/bin:/usr/bin", 1); 120 if (term != NULL) 121 setenv("TERM", term, 1); 122 } 123 if (setgid(pwd->pw_gid) != 0) 124 err(1, "setgid"); 125 if (setusercontext(lcap, pwd, pwd->pw_uid, username 126 ? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN 127 : LOGIN_SETPATH | LOGIN_SETENV) != 0) 128 err(1, "setusercontext"); 129 login_close(lcap); 130 setenv("USER", pwd->pw_name, 1); 131 setenv("HOME", pwd->pw_dir, 1); 132 setenv("SHELL", 133 *pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1); 134 if (clean && chdir(pwd->pw_dir) < 0) 135 err(1, "chdir: %s", pwd->pw_dir); 136 endpwent(); 137 } 138 139 /* Run the specified command, or the shell */ 140 if (argc > 1) { 141 if (execvp(argv[1], argv + 1) < 0) 142 err(1, "execvp: %s", argv[1]); 143 } else { 144 if (!(shell = getenv("SHELL"))) 145 shell = _PATH_BSHELL; 146 if (execlp(shell, shell, "-i", NULL) < 0) 147 err(1, "execlp: %s", shell); 148 } 149 exit(0); 150 } 151 152 static void 153 get_user_info(const char *username, const struct passwd **pwdp, 154 login_cap_t **lcapp) 155 { 156 uid_t uid; 157 const struct passwd *pwd; 158 159 errno = 0; 160 if (username) { 161 pwd = getpwnam(username); 162 if (pwd == NULL) { 163 if (errno) 164 err(1, "getpwnam: %s", username); 165 else 166 errx(1, "%s: no such user", username); 167 } 168 } else { 169 uid = getuid(); 170 pwd = getpwuid(uid); 171 if (pwd == NULL) { 172 if (errno) 173 err(1, "getpwuid: %d", uid); 174 else 175 errx(1, "unknown uid: %d", uid); 176 } 177 } 178 *pwdp = pwd; 179 *lcapp = login_getpwclass(pwd); 180 if (*lcapp == NULL) 181 err(1, "getpwclass: %s", pwd->pw_name); 182 if (initgroups(pwd->pw_name, pwd->pw_gid) < 0) 183 err(1, "initgroups: %s", pwd->pw_name); 184 } 185 186 static void 187 usage(void) 188 { 189 190 fprintf(stderr, "%s\n", 191 "usage: jexec [-l] [-u username | -U username] jail [command ...]"); 192 exit(1); 193 } 194