usr.sbin/jexec/jexec.c

   1 /*-
   2  * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #include <sys/param.h>
  30 #include <sys/jail.h>
  31
  32 #include <err.h>
  33 #include <errno.h>
  34 #include <login_cap.h>
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <pwd.h>
  38 #include <unistd.h>
  39
  40 static void     usage(void);
  41
  42 #define GET_USER_INFO do {                                              \
  43         pwd = getpwnam(username);                                       \
  44         if (pwd == NULL) {                                              \
  45                 if (errno)                                              \
  46                         err(1, "getpwnam: %s", username);               \
  47                 else                                                    \
  48                         errx(1, "%s: no such user", username);          \
  49         }                                                               \
  50         lcap = login_getpwclass(pwd);                                   \
  51         if (lcap == NULL)                                               \
  52                 err(1, "getpwclass: %s", username);                     \
  53         ngroups = NGROUPS;                                              \
  54         if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0) \
  55                 err(1, "getgrouplist: %s", username);                   \
  56 } while (0)
  57
  58 int
  59 main(int argc, char *argv[])
  60 {
  61         int jid;
  62         login_cap_t *lcap = NULL;
  63         struct passwd *pwd = NULL;
  64         gid_t groups[NGROUPS];
  65         int ch, ngroups, uflag, Uflag;
  66         char *username;
  67         ch = uflag = Uflag = 0;
  68         username = NULL;
  69
  70         while ((ch = getopt(argc, argv, "u:U:")) != -1) {
  71                 switch (ch) {
  72                 case 'u':
  73                         username = optarg;
  74                         uflag = 1;
  75                         break;
  76                 case 'U':
  77                         username = optarg;
  78                         Uflag = 1;
  79                         break;
  80                 default:
  81                         usage();
  82                 }
  83         }
  84         argc -= optind;
  85         argv += optind;
  86         if (argc < 2)
  87                 usage();
  88         if (uflag && Uflag)
  89                 usage();
  90         if (uflag)
  91                 GET_USER_INFO;
  92         jid = (int)strtol(argv[0], NULL, 10);
  93         if (jail_attach(jid) == -1)
  94                 err(1, "jail_attach(): %d", jid);
  95         if (chdir("/") == -1)
  96                 err(1, "chdir(): /");
  97         if (username != NULL) {
  98                 if (Uflag)
  99                         GET_USER_INFO;
 100                 if (setgroups(ngroups, groups) != 0)
 101                         err(1, "setgroups");
 102                 if (setgid(pwd->pw_gid) != 0)
 103                         err(1, "setgid");
 104                 if (setusercontext(lcap, pwd, pwd->pw_uid,
 105                     LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0)
 106                         err(1, "setusercontext");
 107                 login_close(lcap);
 108         }
 109         if (execvp(argv[1], argv + 1) == -1)
 110                 err(1, "execvp(): %s", argv[1]);
 111         exit(0);
 112 }
 113
 114 static void
 115 usage(void)
 116 {
 117
 118         fprintf(stderr, "%s%s\n",
 119                 "usage: jexec [-u username | -U username]",
 120                 " jid command ...");
 121         exit(1);
 122 }