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 int env_argc = argc;
63 char **env_argv = argv;
64 char *cleanenv;
65 const struct passwd *pwd = NULL;
66 const char *username, *shell, *term;
67 const char *workdir;
68 const char *jexec_args = "d:e:lnu:U:";
69
70 ch = clean = dflag = uflag = Uflag = 0;
71 username = NULL;
72 workdir = "/";
73
74 while ((ch = getopt(argc, argv, jexec_args)) != -1) {
75 switch (ch) {
76 case 'd':
77 workdir = optarg;
78 dflag = 1;
79 break;
80 case 'e':
81 /* Used later. */
82 if (strchr(optarg, '=') == NULL)
83 errx(1, "%s: Invalid environment variable.", optarg);
84 break;
85 case 'l':
86 clean = 1;
87 break;
88 case 'n':
89 /* Specified name, now unused */
90 break;
91 case 'u':
92 username = optarg;
93 uflag = 1;
94 break;
95 case 'U':
96 username = optarg;
97 Uflag = 1;
98 break;
99 default:
100 usage();
101 }
102 }
103 argc -= optind;
104 argv += optind;
105 if (argc < 1)
106 usage();
107 if (uflag && Uflag)
108 usage();
109 if (uflag || (clean && !Uflag))
110 /* User info from the home environment */
111 get_user_info(username, &pwd, &lcap);
112
113 /* Attach to the jail */
114 jid = jail_getid(argv[0]);
115 if (jid < 0)
116 errx(1, "%s", jail_errmsg);
117 if (jail_attach(jid) == -1)
118 err(1, "jail_attach(%d)", jid);
119 if (chdir(workdir) == -1)
120 err(1, "chdir(): %s", workdir);
121
122 /* Set up user environment */
123 if (clean || username != NULL) {
124 if (Uflag)
125 /* User info from the jail environment */
126 get_user_info(username, &pwd, &lcap);
127 if (clean) {
128 term = getenv("TERM");
129 cleanenv = NULL;
130 environ = &cleanenv;
131 setenv("PATH", "/bin:/usr/bin", 1);
132 if (term != NULL)
133 setenv("TERM", term, 1);
134 }
135 if (setgid(pwd->pw_gid) != 0)
136 err(1, "setgid");
137 if (setusercontext(lcap, pwd, pwd->pw_uid, username
138 ? LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN
139 : LOGIN_SETPATH | LOGIN_SETENV) != 0)
140 err(1, "setusercontext");
141 login_close(lcap);
142 setenv("USER", pwd->pw_name, 1);
143 setenv("HOME", pwd->pw_dir, 1);
144 setenv("SHELL",
145 *pwd->pw_shell ? pwd->pw_shell : _PATH_BSHELL, 1);
146 if (clean && username && !dflag && chdir(pwd->pw_dir) < 0)
147 err(1, "chdir: %s", pwd->pw_dir);
148 endpwent();
149 }
150
151 optreset = 1;
152 optind = 1;
153
154 /* Custom environment */
155 while ((ch = getopt(env_argc, env_argv, jexec_args)) != -1) {
156 switch (ch) {
157 case 'e':
158 if (putenv(optarg) == -1)
159 err(1, "putenv");
160 break;
161 }
162 }
163
164 /* Run the specified command, or the shell */
165 if (argc > 1) {
166 if (execvp(argv[1], argv + 1) < 0)
167 err(1, "execvp: %s", argv[1]);
168 } else {
169 if (!(shell = getenv("SHELL")))
170 shell = _PATH_BSHELL;
171 if (execlp(shell, shell, "-i", NULL) < 0)
172 err(1, "execlp: %s", shell);
173 }
174 exit(0);
175 }
176
177 static void
get_user_info(const char * username,const struct passwd ** pwdp,login_cap_t ** lcapp)178 get_user_info(const char *username, const struct passwd **pwdp,
179 login_cap_t **lcapp)
180 {
181 uid_t uid;
182 const struct passwd *pwd;
183
184 errno = 0;
185 if (username) {
186 pwd = getpwnam(username);
187 if (pwd == NULL) {
188 if (errno)
189 err(1, "getpwnam: %s", username);
190 else
191 errx(1, "%s: no such user", username);
192 }
193 } else {
194 uid = getuid();
195 pwd = getpwuid(uid);
196 if (pwd == NULL) {
197 if (errno)
198 err(1, "getpwuid: %d", uid);
199 else
200 errx(1, "unknown uid: %d", uid);
201 }
202 }
203 *pwdp = pwd;
204 *lcapp = login_getpwclass(pwd);
205 if (*lcapp == NULL)
206 err(1, "getpwclass: %s", pwd->pw_name);
207 if (initgroups(pwd->pw_name, pwd->pw_gid) < 0)
208 err(1, "initgroups: %s", pwd->pw_name);
209 }
210
211 static void
usage(void)212 usage(void)
213 {
214
215 fprintf(stderr, "%s\n",
216 "usage: jexec [-l] [-d working-directory] [[-e name=value] ...]\n"
217 " [-u username | -U username] jail [command ...]");
218 exit(1);
219 }
220