1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 30 #include <sys/param.h> 31 #include <sys/jail.h> 32 #include <sys/socket.h> 33 #include <sys/sysctl.h> 34 35 #include <arpa/inet.h> 36 #include <netinet/in.h> 37 38 #include <err.h> 39 #include <errno.h> 40 #include <jail.h> 41 #include <limits.h> 42 #include <login_cap.h> 43 #include <paths.h> 44 #include <pwd.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 50 extern char **environ; 51 52 static void get_user_info(const char *username, const struct passwd **pwdp, 53 login_cap_t **lcapp); 54 static void usage(void); 55 56 int 57 main(int argc, char *argv[]) 58 { 59 int jid; 60 login_cap_t *lcap = NULL; 61 int ch, clean, uflag, Uflag; 62 char *cleanenv; 63 const struct passwd *pwd = NULL; 64 const char *username, *shell, *term; 65 66 ch = clean = uflag = Uflag = 0; 67 username = NULL; 68 69 while ((ch = getopt(argc, argv, "lnu:U:")) != -1) { 70 switch (ch) { 71 case 'l': 72 clean = 1; 73 break; 74 case 'n': 75 /* Specified name, now unused */ 76 break; 77 case 'u': 78 username = optarg; 79 uflag = 1; 80 break; 81 case 'U': 82 username = optarg; 83 Uflag = 1; 84 break; 85 default: 86 usage(); 87 } 88 } 89 argc -= optind; 90 argv += optind; 91 if (argc < 1) 92 usage(); 93 if (uflag && Uflag) 94 usage(); 95 if (uflag || (clean && !Uflag)) 96 /* User info from the home environment */ 97 get_user_info(username, &pwd, &lcap); 98 99 /* Attach to the jail */ 100 jid = jail_getid(argv[0]); 101 if (jid < 0) 102 errx(1, "%s", jail_errmsg); 103 if (jail_attach(jid) == -1) 104 err(1, "jail_attach(%d)", jid); 105 if (chdir("/") == -1) 106 err(1, "chdir(): /"); 107 108 /* Set up user environment */ 109 if (clean || username != NULL) { 110 if (Uflag) 111 /* User info from the jail environment */ 112 get_user_info(username, &pwd, &lcap); 113 if (clean) { 114 term = getenv("TERM"); 115 cleanenv = NULL; 116 environ = &cleanenv; 117 setenv("PATH", "/bin:/usr/bin", 1); 118 if (term != NULL) 119 setenv("TERM", term, 1); 120 } 121 if (setgid(pwd->pw_gid) != 0) 122 err(1, "setgid"); 123 if (setusercontext(lcap, pwd, pwd->pw_uid, username 124 ? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN 125 : LOGIN_SETPATH | LOGIN_SETENV) != 0) 126 err(1, "setusercontext"); 127 login_close(lcap); 128 setenv("USER", pwd->pw_name, 1); 129 setenv("HOME", pwd->pw_dir, 1); 130 setenv("SHELL", 131 *pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1); 132 if (clean && username && chdir(pwd->pw_dir) < 0) 133 err(1, "chdir: %s", pwd->pw_dir); 134 endpwent(); 135 } 136 137 /* Run the specified command, or the shell */ 138 if (argc > 1) { 139 if (execvp(argv[1], argv + 1) < 0) 140 err(1, "execvp: %s", argv[1]); 141 } else { 142 if (!(shell = getenv("SHELL"))) 143 shell = _PATH_BSHELL; 144 if (execlp(shell, shell, "-i", NULL) < 0) 145 err(1, "execlp: %s", shell); 146 } 147 exit(0); 148 } 149 150 static void 151 get_user_info(const char *username, const struct passwd **pwdp, 152 login_cap_t **lcapp) 153 { 154 uid_t uid; 155 const struct passwd *pwd; 156 157 errno = 0; 158 if (username) { 159 pwd = getpwnam(username); 160 if (pwd == NULL) { 161 if (errno) 162 err(1, "getpwnam: %s", username); 163 else 164 errx(1, "%s: no such user", username); 165 } 166 } else { 167 uid = getuid(); 168 pwd = getpwuid(uid); 169 if (pwd == NULL) { 170 if (errno) 171 err(1, "getpwuid: %d", uid); 172 else 173 errx(1, "unknown uid: %d", uid); 174 } 175 } 176 *pwdp = pwd; 177 *lcapp = login_getpwclass(pwd); 178 if (*lcapp == NULL) 179 err(1, "getpwclass: %s", pwd->pw_name); 180 if (initgroups(pwd->pw_name, pwd->pw_gid) < 0) 181 err(1, "initgroups: %s", pwd->pw_name); 182 } 183 184 static void 185 usage(void) 186 { 187 188 fprintf(stderr, "%s\n", 189 "usage: jexec [-l] [-u username | -U username] jail [command ...]"); 190 exit(1); 191 } 192