xref: /freebsd/usr.sbin/jexec/jexec.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  * $FreeBSD$
27  */
28 
29 #include <sys/param.h>
30 #include <sys/jail.h>
31 
32 #include <err.h>
33 #include <errno.h>
34 #include <login_cap.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <pwd.h>
38 #include <unistd.h>
39 
40 static void	usage(void);
41 
42 #define GET_USER_INFO do {						\
43 	pwd = getpwnam(username);					\
44 	if (pwd == NULL) {						\
45 		if (errno)						\
46 			err(1, "getpwnam: %s", username);		\
47 		else							\
48 			errx(1, "%s: no such user", username);		\
49 	}								\
50 	lcap = login_getpwclass(pwd);					\
51 	if (lcap == NULL)						\
52 		err(1, "getpwclass: %s", username);			\
53 	ngroups = NGROUPS;						\
54 	if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0)	\
55 		err(1, "getgrouplist: %s", username);			\
56 } while (0)
57 
58 int
59 main(int argc, char *argv[])
60 {
61 	int jid;
62 	login_cap_t *lcap = NULL;
63 	struct passwd *pwd = NULL;
64 	gid_t groups[NGROUPS];
65 	int ch, ngroups, uflag, Uflag;
66 	char *username;
67 	ch = uflag = Uflag = 0;
68 	username = NULL;
69 
70 	while ((ch = getopt(argc, argv, "u:U:")) != -1) {
71 		switch (ch) {
72 		case 'u':
73 			username = optarg;
74 			uflag = 1;
75 			break;
76 		case 'U':
77 			username = optarg;
78 			Uflag = 1;
79 			break;
80 		default:
81 			usage();
82 		}
83 	}
84 	argc -= optind;
85 	argv += optind;
86 	if (argc < 2)
87 		usage();
88 	if (uflag && Uflag)
89 		usage();
90 	if (uflag)
91 		GET_USER_INFO;
92 	jid = (int)strtol(argv[0], NULL, 10);
93 	if (jail_attach(jid) == -1)
94 		err(1, "jail_attach(): %d", jid);
95 	if (chdir("/") == -1)
96 		err(1, "chdir(): /");
97 	if (username != NULL) {
98 		if (Uflag)
99 			GET_USER_INFO;
100 		if (setgroups(ngroups, groups) != 0)
101 			err(1, "setgroups");
102 		if (setgid(pwd->pw_gid) != 0)
103 			err(1, "setgid");
104 		if (setusercontext(lcap, pwd, pwd->pw_uid,
105 		    LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
106 			err(1, "setusercontext");
107 		login_close(lcap);
108 	}
109 	if (execvp(argv[1], argv + 1) == -1)
110 		err(1, "execvp(): %s", argv[1]);
111 	exit(0);
112 }
113 
114 static void
115 usage(void)
116 {
117 
118 	fprintf(stderr, "%s%s\n",
119 		"usage: jexec [-u username | -U username]",
120 		" jid command ...");
121 	exit(1);
122 }
123