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, 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
get_user_info(const char * username,const struct passwd ** pwdp,login_cap_t ** lcapp)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
usage(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