jail.c revision 158475 
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 158475 2006-05-12 15:14:43Z matteo $");
12
13#include <sys/param.h>
14#include <sys/jail.h>
15#include <sys/sysctl.h>
16
17#include <netinet/in.h>
18#include <arpa/inet.h>
19
20#include <err.h>
21#include <errno.h>
22#include <grp.h>
23#include <login_cap.h>
24#include <paths.h>
25#include <pwd.h>
26#include <stdio.h>
27#include <stdlib.h>
28#include <string.h>
29#include <unistd.h>
30
31static void	usage(void);
32extern char	**environ;
33
34#define GET_USER_INFO do {						\
35	pwd = getpwnam(username);					\
36	if (pwd == NULL) {						\
37		if (errno)						\
38			err(1, "getpwnam: %s", username);		\
39		else							\
40			errx(1, "%s: no such user", username);		\
41	}								\
42	lcap = login_getpwclass(pwd);					\
43	if (lcap == NULL)						\
44		err(1, "getpwclass: %s", username);			\
45	ngroups = NGROUPS;						\
46	if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0)	\
47		err(1, "getgrouplist: %s", username);			\
48} while (0)
49
50int
51main(int argc, char **argv)
52{
53	login_cap_t *lcap = NULL;
54	struct jail j;
55	struct passwd *pwd = NULL;
56	struct in_addr in;
57	gid_t groups[NGROUPS];
58	int ch, i, iflag, Jflag, lflag, ngroups, securelevel, uflag, Uflag;
59	char path[PATH_MAX], *ep, *username, *JidFile;
60	static char *cleanenv;
61	const char *shell, *p = NULL;
62	long ltmp;
63	FILE *fp;
64
65	iflag = Jflag = lflag = uflag = Uflag = 0;
66	securelevel = -1;
67	username = JidFile = cleanenv = NULL;
68	fp = NULL;
69
70	while ((ch = getopt(argc, argv, "ils:u:U:J:")) != -1) {
71		switch (ch) {
72		case 'i':
73			iflag = 1;
74			break;
75		case 'J':
76			JidFile = optarg;
77			Jflag = 1;
78			break;
79		case 's':
80			ltmp = strtol(optarg, &ep, 0);
81			if (*ep || ep == optarg || ltmp > INT_MAX || !ltmp)
82				errx(1, "invalid securelevel: `%s'", optarg);
83			securelevel = ltmp;
84			break;
85		case 'u':
86			username = optarg;
87			uflag = 1;
88			break;
89		case 'U':
90			username = optarg;
91			Uflag = 1;
92			break;
93		case 'l':
94			lflag = 1;
95			break;
96		default:
97			usage();
98		}
99	}
100	argc -= optind;
101	argv += optind;
102	if (argc < 4)
103		usage();
104	if (uflag && Uflag)
105		usage();
106	if (lflag && username == NULL)
107		usage();
108	if (uflag)
109		GET_USER_INFO;
110	if (realpath(argv[0], path) == NULL)
111		err(1, "realpath: %s", argv[0]);
112	if (chdir(path) != 0)
113		err(1, "chdir: %s", path);
114	memset(&j, 0, sizeof(j));
115	j.version = 0;
116	j.path = path;
117	j.hostname = argv[1];
118	if (inet_aton(argv[2], &in) == 0)
119		errx(1, "Could not make sense of ip-number: %s", argv[2]);
120	j.ip_number = ntohl(in.s_addr);
121	if (Jflag) {
122		fp = fopen(JidFile, "w");
123		if (fp == NULL)
124			errx(1, "Could not create JidFile: %s", JidFile);
125	}
126	i = jail(&j);
127	if (i == -1)
128		err(1, "jail");
129	if (iflag) {
130		printf("%d\n", i);
131		fflush(stdout);
132	}
133	if (Jflag) {
134		if (fp != NULL) {
135			fprintf(fp, "%d\t%s\t%s\t%s\t%s\n",
136			    i, j.path, j.hostname, argv[2], argv[3]);
137			(void)fclose(fp);
138		} else {
139			errx(1, "Could not write JidFile: %s", JidFile);
140		}
141	}
142	if (securelevel > 0) {
143		if (sysctlbyname("kern.securelevel", NULL, 0, &securelevel,
144		    sizeof(securelevel)))
145			err(1, "Can not set securelevel to %d", securelevel);
146	}
147	if (username != NULL) {
148		if (Uflag)
149			GET_USER_INFO;
150		if (lflag) {
151			p = getenv("TERM");
152			environ = &cleanenv;
153		}
154		if (setgroups(ngroups, groups) != 0)
155			err(1, "setgroups");
156		if (setgid(pwd->pw_gid) != 0)
157			err(1, "setgid");
158		if (setusercontext(lcap, pwd, pwd->pw_uid,
159		    LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
160			err(1, "setusercontext");
161		login_close(lcap);
162	}
163	if (lflag) {
164		if (*pwd->pw_shell)
165			shell = pwd->pw_shell;
166		else
167			shell = _PATH_BSHELL;
168		if (chdir(pwd->pw_dir) < 0)
169			errx(1, "no home directory");
170		setenv("HOME", pwd->pw_dir, 1);
171		setenv("SHELL", shell, 1);
172		setenv("USER", pwd->pw_name, 1);
173		if (p)
174			setenv("TERM", p, 1);
175	}
176	if (execv(argv[3], argv + 3) != 0)
177		err(1, "execv: %s", argv[3]);
178	exit(0);
179}
180
181static void
182usage(void)
183{
184
185	(void)fprintf(stderr, "%s%s%s\n",
186	     "usage: jail [-i] [-J jid_file] [-s securelevel] [-l -u ",
187	     "username | -U username]",
188	     " path hostname ip-number command ...");
189	exit(1);
190}
191