usr.sbin/jail/jail.c

   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("$FreeBSD$");
  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
  30 static void     usage(void);
  31 extern 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
  49 int
  50 main(int argc, char **argv)
  51 {
  52         login_cap_t *lcap = NULL;
  53         struct jail j;
  54         struct passwd *pwd = NULL;
  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 = NULL;
  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
 147 static void
 148 usage(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 }