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
main(int argc,char * argv[])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
get_user_info(const char * username,const struct passwd ** pwdp,login_cap_t ** lcapp)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
usage(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