1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2003 Mike Barcroft <[email protected]>
5 * Copyright (c) 2008 Bjoern A. Zeeb <[email protected]>
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
main(int argc,char * argv[])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
get_user_info(const char * username,const struct passwd ** pwdp,login_cap_t ** lcapp)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
usage(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