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, dflag, uflag, Uflag; 62 char *cleanenv; 63 const struct passwd *pwd = NULL; 64 const char *username, *shell, *term; 65 const char *workdir; 66 67 ch = clean = dflag = uflag = Uflag = 0; 68 username = NULL; 69 workdir = "/"; 70 71 while ((ch = getopt(argc, argv, "d:lnu:U:")) != -1) { 72 switch (ch) { 73 case 'd': 74 workdir = optarg; 75 dflag = 1; 76 break; 77 case 'l': 78 clean = 1; 79 break; 80 case 'n': 81 /* Specified name, now unused */ 82 break; 83 case 'u': 84 username = optarg; 85 uflag = 1; 86 break; 87 case 'U': 88 username = optarg; 89 Uflag = 1; 90 break; 91 default: 92 usage(); 93 } 94 } 95 argc -= optind; 96 argv += optind; 97 if (argc < 1) 98 usage(); 99 if (uflag && Uflag) 100 usage(); 101 if (uflag || (clean && !Uflag)) 102 /* User info from the home environment */ 103 get_user_info(username, &pwd, &lcap); 104 105 /* Attach to the jail */ 106 jid = jail_getid(argv[0]); 107 if (jid < 0) 108 errx(1, "%s", jail_errmsg); 109 if (jail_attach(jid) == -1) 110 err(1, "jail_attach(%d)", jid); 111 if (chdir(workdir) == -1) 112 err(1, "chdir(): %s", workdir); 113 114 /* Set up user environment */ 115 if (clean || username != NULL) { 116 if (Uflag) 117 /* User info from the jail environment */ 118 get_user_info(username, &pwd, &lcap); 119 if (clean) { 120 term = getenv("TERM"); 121 cleanenv = NULL; 122 environ = &cleanenv; 123 setenv("PATH", "/bin:/usr/bin", 1); 124 if (term != NULL) 125 setenv("TERM", term, 1); 126 } 127 if (setgid(pwd->pw_gid) != 0) 128 err(1, "setgid"); 129 if (setusercontext(lcap, pwd, pwd->pw_uid, username 130 ? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN 131 : LOGIN_SETPATH | LOGIN_SETENV) != 0) 132 err(1, "setusercontext"); 133 login_close(lcap); 134 setenv("USER", pwd->pw_name, 1); 135 setenv("HOME", pwd->pw_dir, 1); 136 setenv("SHELL", 137 *pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1); 138 if (clean && username && !dflag && chdir(pwd->pw_dir) < 0) 139 err(1, "chdir: %s", pwd->pw_dir); 140 endpwent(); 141 } 142 143 /* Run the specified command, or the shell */ 144 if (argc > 1) { 145 if (execvp(argv[1], argv + 1) < 0) 146 err(1, "execvp: %s", argv[1]); 147 } else { 148 if (!(shell = getenv("SHELL"))) 149 shell = _PATH_BSHELL; 150 if (execlp(shell, shell, "-i", NULL) < 0) 151 err(1, "execlp: %s", shell); 152 } 153 exit(0); 154 } 155 156 static void 157 get_user_info(const char *username, const struct passwd **pwdp, 158 login_cap_t **lcapp) 159 { 160 uid_t uid; 161 const struct passwd *pwd; 162 163 errno = 0; 164 if (username) { 165 pwd = getpwnam(username); 166 if (pwd == NULL) { 167 if (errno) 168 err(1, "getpwnam: %s", username); 169 else 170 errx(1, "%s: no such user", username); 171 } 172 } else { 173 uid = getuid(); 174 pwd = getpwuid(uid); 175 if (pwd == NULL) { 176 if (errno) 177 err(1, "getpwuid: %d", uid); 178 else 179 errx(1, "unknown uid: %d", uid); 180 } 181 } 182 *pwdp = pwd; 183 *lcapp = login_getpwclass(pwd); 184 if (*lcapp == NULL) 185 err(1, "getpwclass: %s", pwd->pw_name); 186 if (initgroups(pwd->pw_name, pwd->pw_gid) < 0) 187 err(1, "initgroups: %s", pwd->pw_name); 188 } 189 190 static void 191 usage(void) 192 { 193 194 fprintf(stderr, "%s\n", 195 "usage: jexec [-l] [-d working-directory] [-u username | -U username] jail\n" 196 " [command ...]"); 197 exit(1); 198 } 199