jexec.c revision 179415 
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 179415 2008-05-29 17:00:01Z mr $
27 */
28
29#include <sys/param.h>
30#include <sys/jail.h>
31#include <sys/sysctl.h>
32
33#include <arpa/inet.h>
34
35#include <err.h>
36#include <errno.h>
37#include <limits.h>
38#include <login_cap.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <pwd.h>
42#include <unistd.h>
43#include <string.h>
44
45static void	usage(void);
46static int	addr2jid(const char *addr);
47
48#define GET_USER_INFO do {						\
49	pwd = getpwnam(username);					\
50	if (pwd == NULL) {						\
51		if (errno)						\
52			err(1, "getpwnam: %s", username);		\
53		else							\
54			errx(1, "%s: no such user", username);		\
55	}								\
56	lcap = login_getpwclass(pwd);					\
57	if (lcap == NULL)						\
58		err(1, "getpwclass: %s", username);			\
59	ngroups = NGROUPS;						\
60	if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0)	\
61		err(1, "getgrouplist: %s", username);			\
62} while (0)
63
64int
65main(int argc, char *argv[])
66{
67	int jid;
68	login_cap_t *lcap = NULL;
69	struct passwd *pwd = NULL;
70	gid_t groups[NGROUPS];
71	int ch, ngroups, uflag, Uflag, hflag;
72	char *username;
73	ch = uflag = Uflag = hflag = 0;
74	username = NULL;
75
76	while ((ch = getopt(argc, argv, "u:U:h")) != -1) {
77		switch (ch) {
78		case 'u':
79			username = optarg;
80			uflag = 1;
81			break;
82		case 'U':
83			username = optarg;
84			Uflag = 1;
85			break;
86		case 'h':
87			hflag = 1;
88			break;
89		default:
90			usage();
91		}
92	}
93	argc -= optind;
94	argv += optind;
95	if (argc < 2)
96		usage();
97	if (uflag && Uflag)
98		usage();
99	if (uflag)
100		GET_USER_INFO;
101	if (hflag) {
102		if ((jid = addr2jid(argv[0])) == 0)
103			errx(1, "jail_attach(): Cannot convert %s to jid", argv[0]);
104	} else
105		jid = (int)strtol(argv[0], NULL, 10);
106	if (jail_attach(jid) == -1)
107		err(1, "jail_attach(): %d", jid);
108	if (chdir("/") == -1)
109		err(1, "chdir(): /");
110	if (username != NULL) {
111		if (Uflag)
112			GET_USER_INFO;
113		if (setgroups(ngroups, groups) != 0)
114			err(1, "setgroups");
115		if (setgid(pwd->pw_gid) != 0)
116			err(1, "setgid");
117		if (setusercontext(lcap, pwd, pwd->pw_uid,
118		    LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
119			err(1, "setusercontext");
120		login_close(lcap);
121	}
122	if (execvp(argv[1], argv + 1) == -1)
123		err(1, "execvp(): %s", argv[1]);
124	exit(0);
125}
126
127static void
128usage(void)
129{
130
131	fprintf(stderr, "%s%s\n",
132		"usage: jexec [-u username | -U username]",
133		" [-h hostname | -h ip-number | jid] command ...");
134	exit(1);
135}
136
137static int
138addr2jid(const char *addr)
139{
140	struct xprison *sxp, *xp;
141	struct in_addr in;
142	size_t i, len;
143	int jid, cnt;
144	jid = cnt = 0;
145
146	if (sysctlbyname("security.jail.list", NULL, &len, NULL, 0) == -1)
147		err(1, "sysctlbyname(): security.jail.list");
148	for (i = 0; i < 4; i++) {
149		if (len <= 0)
150			err(1, "sysctlbyname(): len <=0");
151		sxp = xp = malloc(len);
152		if (sxp == NULL)
153			err(1, "malloc()");
154		if (sysctlbyname("security.jail.list", xp, &len, NULL, 0) == -1) {
155			if (errno == ENOMEM) {
156				free(sxp);
157				sxp = NULL;
158				continue;
159			}
160			err(1, "sysctlbyname(): security.jail.list");
161		}
162		break;
163	}
164	if (sxp == NULL)
165		err(1, "sysctlbyname(): security.jail.list");
166	if (len < sizeof(*xp) || len % sizeof(*xp) ||
167	    xp->pr_version != XPRISON_VERSION)
168		errx(1, "Kernel and userland out of sync");
169	for (i = 0; i < len / sizeof(*xp); i++) {
170		in.s_addr = ntohl(xp->pr_ip);
171		if ((strcmp(inet_ntoa(in), addr) == 0) ||
172		    (strcmp(xp->pr_host, addr) == 0)) {
173			jid = xp->pr_id;
174			cnt++;
175		}
176		xp++;
177	}
178	free(sxp);
179	if (cnt == 1)
180		return (jid);
181	else
182		return(0);
183}
184