jail.c revision 136051 
1/*
2 * ----------------------------------------------------------------------------
3 * "THE BEER-WARE LICENSE" (Revision 42):
4 * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
5 * can do whatever you want with this stuff. If we meet some day, and you think
6 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
7 * ----------------------------------------------------------------------------
8 */
9
10#include <sys/cdefs.h>
11__FBSDID("$FreeBSD: head/usr.sbin/jail/jail.c 136051 2004-10-02 11:40:48Z stefanf $");
12
13#include <sys/param.h>
14#include <sys/jail.h>
15
16#include <netinet/in.h>
17#include <arpa/inet.h>
18
19#include <err.h>
20#include <errno.h>
21#include <grp.h>
22#include <login_cap.h>
23#include <paths.h>
24#include <pwd.h>
25#include <stdio.h>
26#include <stdlib.h>
27#include <string.h>
28#include <unistd.h>
29
30static void	usage(void);
31extern char	**environ;
32
33#define GET_USER_INFO do {						\
34	pwd = getpwnam(username);					\
35	if (pwd == NULL) {						\
36		if (errno)						\
37			err(1, "getpwnam: %s", username);		\
38		else							\
39			errx(1, "%s: no such user", username);		\
40	}								\
41	lcap = login_getpwclass(pwd);					\
42	if (lcap == NULL)						\
43		err(1, "getpwclass: %s", username);			\
44	ngroups = NGROUPS;						\
45	if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0)	\
46		err(1, "getgrouplist: %s", username);			\
47} while (0)
48
49int
50main(int argc, char **argv)
51{
52	login_cap_t *lcap;
53	struct jail j;
54	struct passwd *pwd;
55	struct in_addr in;
56	gid_t groups[NGROUPS];
57	int ch, i, iflag, lflag, ngroups, uflag, Uflag;
58	char path[PATH_MAX], *username;
59	static char *cleanenv;
60	const char *shell, *p;
61
62	iflag = lflag = uflag = Uflag = 0;
63	username = cleanenv = NULL;
64
65	while ((ch = getopt(argc, argv, "ilu:U:")) != -1) {
66		switch (ch) {
67		case 'i':
68			iflag = 1;
69			break;
70		case 'u':
71			username = optarg;
72			uflag = 1;
73			break;
74		case 'U':
75			username = optarg;
76			Uflag = 1;
77			break;
78		case 'l':
79			lflag = 1;
80			break;
81		default:
82			usage();
83		}
84	}
85	argc -= optind;
86	argv += optind;
87	if (argc < 4)
88		usage();
89	if (uflag && Uflag)
90		usage();
91	if (lflag && username == NULL)
92		usage();
93	if (uflag)
94		GET_USER_INFO;
95	if (realpath(argv[0], path) == NULL)
96		err(1, "realpath: %s", argv[0]);
97	if (chdir(path) != 0)
98		err(1, "chdir: %s", path);
99	memset(&j, 0, sizeof(j));
100	j.version = 0;
101	j.path = path;
102	j.hostname = argv[1];
103	if (inet_aton(argv[2], &in) == 0)
104		errx(1, "Could not make sense of ip-number: %s", argv[2]);
105	j.ip_number = ntohl(in.s_addr);
106	i = jail(&j);
107	if (i == -1)
108		err(1, "jail");
109	if (iflag) {
110		printf("%d\n", i);
111		fflush(stdout);
112	}
113	if (username != NULL) {
114		if (Uflag)
115			GET_USER_INFO;
116		if (lflag) {
117			p = getenv("TERM");
118			environ = &cleanenv;
119		}
120		if (setgroups(ngroups, groups) != 0)
121			err(1, "setgroups");
122		if (setgid(pwd->pw_gid) != 0)
123			err(1, "setgid");
124		if (setusercontext(lcap, pwd, pwd->pw_uid,
125		    LOGIN_SETALL & ~LOGIN_SETGROUP) != 0)
126			err(1, "setusercontext");
127		login_close(lcap);
128	}
129	if (lflag) {
130		if (*pwd->pw_shell)
131			shell = pwd->pw_shell;
132		else
133			shell = _PATH_BSHELL;
134		if (chdir(pwd->pw_dir) < 0)
135			errx(1, "no home directory");
136		setenv("HOME", pwd->pw_dir, 1);
137		setenv("SHELL", shell, 1);
138		setenv("USER", pwd->pw_name, 1);
139		if (p)
140			setenv("TERM", p, 1);
141	}
142	if (execv(argv[3], argv + 3) != 0)
143		err(1, "execv: %s", argv[3]);
144	exit(0);
145}
146
147static void
148usage(void)
149{
150
151	(void)fprintf(stderr, "%s%s\n",
152	     "usage: jail [-i] [-l -u username | -U username]",
153	     " path hostname ip-number command ...");
154	exit(1);
155}
156