xref: /freebsd/usr.sbin/jail/jail.c (revision 729362425c09cf6b362366aabc6fb547eee8035a)
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  * $FreeBSD$
10  *
11  */
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 <grp.h>
21 #include <login_cap.h>
22 #include <pwd.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <unistd.h>
27 
28 static void	usage(void);
29 
30 int
31 main(int argc, char **argv)
32 {
33 	login_cap_t *lcap;
34 	struct jail j;
35 	struct passwd *pwd;
36 	struct in_addr in;
37 	int ch, groups[NGROUPS], i, ngroups;
38 	char *username;
39 
40 	username = NULL;
41 
42 	while ((ch = getopt(argc, argv, "u:")) != -1)
43 		switch (ch) {
44 		case 'u':
45 			username = optarg;
46 			break;
47 		default:
48 			usage();
49 			break;
50 		}
51 	argc -= optind;
52 	argv += optind;
53 	if (argc < 4)
54 		usage();
55 
56 	if (username != NULL) {
57 		pwd = getpwnam(username);
58 		if (pwd == NULL)
59 			err(1, "getpwnam %s", username);
60 		lcap = login_getpwclass(pwd);
61 		if (lcap == NULL)
62 			err(1, "getpwclass failed", username);
63 		ngroups = NGROUPS;
64 		i = getgrouplist(username, pwd->pw_gid, groups, &ngroups);
65 		if (i)
66 			err(1, "getgrouplist %s", username);
67 	}
68 	i = chdir(argv[0]);
69 	if (i)
70 		err(1, "chdir %s", argv[0]);
71 	memset(&j, 0, sizeof(j));
72 	j.version = 0;
73 	j.path = argv[0];
74 	j.hostname = argv[1];
75 	i = inet_aton(argv[2], &in);
76 	if (!i)
77 		errx(1, "Couldn't make sense of ip-number\n");
78 	j.ip_number = ntohl(in.s_addr);
79 	i = jail(&j);
80 	if (i)
81 		err(1, "Imprisonment failed");
82 	if (username != NULL) {
83 		i = setgroups(ngroups, groups);
84 		if (i)
85 			err(1, "setgroups failed");
86 		i = setgid(pwd->pw_gid);
87 		if (i)
88 			err(1, "setgid failed");
89 		i = setusercontext(lcap, pwd, pwd->pw_uid,
90 		    LOGIN_SETALL & ~LOGIN_SETGROUP);
91 		if (i)
92 			err(1, "setusercontext failed");
93 	}
94 	i = execv(argv[3], argv + 3);
95 	if (i)
96 		err(1, "execv(%s)", argv[3]);
97 	exit (0);
98 }
99 
100 static void
101 usage(void)
102 {
103 
104 	errx(1,
105 	    "Usage: jail [-u username] path hostname ip-number command ...");
106 }
107