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;
  53         struct jail j;
  54         struct passwd *pwd;
  55         struct in_addr in;
  56         int ch, groups[NGROUPS], i, iflag, lflag, ngroups, uflag, Uflag;
  57         char path[PATH_MAX], *username;
  58         static char *cleanenv;
  59         const char *shell, *p;
  60
  61         iflag = lflag = uflag = Uflag = 0;
  62         username = cleanenv = NULL;
  63
  64         while ((ch = getopt(argc, argv, "ilu:U:")) != -1) {
  65                 switch (ch) {
  66                 case 'i':
  67                         iflag = 1;
  68                         break;
  69                 case 'u':
  70                         username = optarg;
  71                         uflag = 1;
  72                         break;
  73                 case 'U':
  74                         username = optarg;
  75                         Uflag = 1;
  76                         break;
  77                 case 'l':
  78                         lflag = 1;
  79                         break;
  80                 default:
  81                         usage();
  82                 }
  83         }
  84         argc -= optind;
  85         argv += optind;
  86         if (argc < 4)
  87                 usage();
  88         if (uflag && Uflag)
  89                 usage();
  90         if (lflag && username == NULL)
  91                 usage();
  92         if (uflag)
  93                 GET_USER_INFO;
  94         if (realpath(argv[0], path) == NULL)
  95                 err(1, "realpath: %s", argv[0]);
  96         if (chdir(path) != 0)
  97                 err(1, "chdir: %s", path);
  98         memset(&j, 0, sizeof(j));
  99         j.version = 0;
 100         j.path = path;
 101         j.hostname = argv[1];
 102         if (inet_aton(argv[2], &in) == 0)
 103                 errx(1, "Could not make sense of ip-number: %s", argv[2]);
 104         j.ip_number = ntohl(in.s_addr);
 105         i = jail(&j);
 106         if (i == -1)
 107                 err(1, "jail");
 108         if (iflag) {
 109                 printf("%d\n", i);
 110                 fflush(stdout);
 111         }
 112         if (username != NULL) {
 113                 if (Uflag)
 114                         GET_USER_INFO;
 115                 if (lflag) {
 116                         p = getenv("TERM");
 117                         environ = &cleanenv;
 118                 }
 119                 if (setgroups(ngroups, groups) != 0)
 120                         err(1, "setgroups");
 121                 if (setgid(pwd->pw_gid) != 0)
 122                         err(1, "setgid");
 123                 if (setusercontext(lcap, pwd, pwd->pw_uid,
 124                     LOGIN_SETALL & ~LOGIN_SETGROUP) != 0)
 125                         err(1, "setusercontext");
 126                 login_close(lcap);
 127         }
 128         if (lflag) {
 129                 if (*pwd->pw_shell)
 130                         shell = pwd->pw_shell;
 131                 else
 132                         shell = _PATH_BSHELL;
 133                 if (chdir(pwd->pw_dir) < 0)
 134                         errx(1, "no home directory");
 135                 setenv("HOME", pwd->pw_dir, 1);
 136                 setenv("SHELL", shell, 1);
 137                 setenv("USER", pwd->pw_name, 1);
 138                 if (p)
 139                         setenv("TERM", p, 1);
 140         }
 141         if (execv(argv[3], argv + 3) != 0)
 142                 err(1, "execv: %s", argv[3]);
 143         exit(0);
 144 }
 145
 146 static void
 147 usage(void)
 148 {
 149
 150         (void)fprintf(stderr, "%s%s\n",
 151              "usage: jail [-i] [-l -u username | -U username]",
 152              " path hostname ip-number command ...");
 153         exit(1);
 154 }