6/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 #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
  31 static void     usage(void);
  32 extern 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
  50 int
  51 main(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
 181 static void
 182 usage(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 }