xref: /freebsd/usr.sbin/jail/jail.c (revision 628f583ce90d3587595c2f4dd16d57eec3511af3)
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], 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: %s", username);
63 		ngroups = NGROUPS;
64 		if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0)
65 			err(1, "getgrouplist: %s", username);
66 	}
67 	if (chdir(argv[0]) != 0)
68 		err(1, "chdir: %s", argv[0]);
69 	memset(&j, 0, sizeof(j));
70 	j.version = 0;
71 	j.path = argv[0];
72 	j.hostname = argv[1];
73 	if (inet_aton(argv[2], &in) == 0)
74 		errx(1, "Could not make sense of ip-number: %s", argv[2]);
75 	j.ip_number = ntohl(in.s_addr);
76 	if (jail(&j) != 0)
77 		err(1, "jail");
78 	if (username != NULL) {
79 		if (setgroups(ngroups, groups) != 0)
80 			err(1, "setgroups");
81 		if (setgid(pwd->pw_gid) != 0)
82 			err(1, "setgid");
83 		if (setusercontext(lcap, pwd, pwd->pw_uid,
84 		    LOGIN_SETALL & ~LOGIN_SETGROUP) != 0)
85 			err(1, "setusercontext");
86 	}
87 	if (execv(argv[3], argv + 3) != 0)
88 		err(1, "execv: %s", argv[3]);
89 	exit (0);
90 }
91 
92 static void
93 usage(void)
94 {
95 
96 	(void)fprintf(stderr, "%s\n",
97 	    "Usage: jail [-u username] path hostname ip-number command ...");
98 	exit(1);
99 }
100