jexec.c revision 162801 
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: head/usr.sbin/jexec/jexec.c 162801 2006-09-29 17:04:03Z ru $
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
40static 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
58int
59main(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
114static void
115usage(void)
116{
117
118	fprintf(stderr, "%s%s\n",
119		"usage: jexec [-u username | -U username]",
120		" jid command ...");
121	exit(1);
122}
123