src/runcon.c

   1 /* runcon -- run command with specified security context
   2    Copyright (C) 2005-2013 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 /*
  18  * runcon [ context
  19  *          | ( [ -c ] [ -r role ] [-t type] [ -u user ] [ -l levelrange ] )
  20  *          command [arg1 [arg2 ...] ]
  21  *
  22  * attempt to run the specified command with the specified context.
  23  *
  24  * -r role  : use the current context with the specified role
  25  * -t type  : use the current context with the specified type
  26  * -u user  : use the current context with the specified user
  27  * -l level : use the current context with the specified level range
  28  * -c       : compute process transition context before modifying
  29  *
  30  * Contexts are interpreted as follows:
  31  *
  32  * Number of       MLS
  33  * components    system?
  34  *
  35  *     1            -         type
  36  *     2            -         role:type
  37  *     3            Y         role:type:range
  38  *     3            N         user:role:type
  39  *     4            Y         user:role:type:range
  40  *     4            N         error
  41  */
  42
  43 #include <config.h>
  44 #include <stdio.h>
  45 #include <getopt.h>
  46 #include <selinux/selinux.h>
  47 #include <selinux/context.h>
  48 #ifdef HAVE_SELINUX_FLASK_H
  49 # include <selinux/flask.h>
  50 #else
  51 # define SECCLASS_PROCESS 0
  52 #endif
  53 #include <sys/types.h>
  54 #include "system.h"
  55 #include "error.h"
  56 #include "quote.h"
  57 #include "quotearg.h"
  58
  59 /* The official name of this program (e.g., no 'g' prefix).  */
  60 #define PROGRAM_NAME "runcon"
  61
  62 #define AUTHORS proper_name ("Russell Coker")
  63
  64 static struct option const long_options[] =
  65 {
  66   {"role", required_argument, NULL, 'r'},
  67   {"type", required_argument, NULL, 't'},
  68   {"user", required_argument, NULL, 'u'},
  69   {"range", required_argument, NULL, 'l'},
  70   {"compute", no_argument, NULL, 'c'},
  71   {GETOPT_HELP_OPTION_DECL},
  72   {GETOPT_VERSION_OPTION_DECL},
  73   {NULL, 0, NULL, 0}
  74 };
  75
  76 void
  77 usage (int status)
  78 {
  79   if (status != EXIT_SUCCESS)
  80     emit_try_help ();
  81   else
  82     {
  83       printf (_("\
  84 Usage: %s CONTEXT COMMAND [args]\n\
  85   or:  %s [ -c ] [-u USER] [-r ROLE] [-t TYPE] [-l RANGE] COMMAND [args]\n\
  86 "), program_name, program_name);
  87       fputs (_("\
  88 Run a program in a different SELinux security context.\n\
  89 With neither CONTEXT nor COMMAND, print the current security context.\n\
  90 "), stdout);
  91
  92       emit_mandatory_arg_note ();
  93
  94       fputs (_("\
  95   CONTEXT            Complete security context\n\
  96   -c, --compute      compute process transition context before modifying\n\
  97   -t, --type=TYPE    type (for same role as parent)\n\
  98   -u, --user=USER    user identity\n\
  99   -r, --role=ROLE    role\n\
 100   -l, --range=RANGE  levelrange\n\
 101 \n\
 102 "), stdout);
 103       fputs (HELP_OPTION_DESCRIPTION, stdout);
 104       fputs (VERSION_OPTION_DESCRIPTION, stdout);
 105       emit_ancillary_info ();
 106     }
 107   exit (status);
 108 }
 109
 110 int
 111 main (int argc, char **argv)
 112 {
 113   char *role = NULL;
 114   char *range = NULL;
 115   char *user = NULL;
 116   char *type = NULL;
 117   char *context = NULL;
 118   security_context_t cur_context = NULL;
 119   security_context_t file_context = NULL;
 120   security_context_t new_context = NULL;
 121   bool compute_trans = false;
 122
 123   context_t con;
 124
 125   initialize_main (&argc, &argv);
 126   set_program_name (argv[0]);
 127   setlocale (LC_ALL, "");
 128   bindtextdomain (PACKAGE, LOCALEDIR);
 129   textdomain (PACKAGE);
 130
 131   atexit (close_stdout);
 132
 133   while (1)
 134     {
 135       int option_index = 0;
 136       int c = getopt_long (argc, argv, "+r:t:u:l:c", long_options,
 137                            &option_index);
 138       if (c == -1)
 139         break;
 140       switch (c)
 141         {
 142         case 'r':
 143           if (role)
 144             error (EXIT_FAILURE, 0, _("multiple roles"));
 145           role = optarg;
 146           break;
 147         case 't':
 148           if (type)
 149             error (EXIT_FAILURE, 0, _("multiple types"));
 150           type = optarg;
 151           break;
 152         case 'u':
 153           if (user)
 154             error (EXIT_FAILURE, 0, _("multiple users"));
 155           user = optarg;
 156           break;
 157         case 'l':
 158           if (range)
 159             error (EXIT_FAILURE, 0, _("multiple levelranges"));
 160           range = optarg;
 161           break;
 162         case 'c':
 163           compute_trans = true;
 164           break;
 165
 166         case_GETOPT_HELP_CHAR;
 167         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 168         default:
 169           usage (EXIT_FAILURE);
 170           break;
 171         }
 172     }
 173
 174   if (argc - optind == 0)
 175     {
 176       if (getcon (&cur_context) < 0)
 177         error (EXIT_FAILURE, errno, _("failed to get current context"));
 178       fputs (cur_context, stdout);
 179       fputc ('\n', stdout);
 180       exit (EXIT_SUCCESS);
 181     }
 182
 183   if (!(user || role || type || range || compute_trans))
 184     {
 185       if (optind >= argc)
 186         {
 187           error (0, 0, _("you must specify -c, -t, -u, -l, -r, or context"));
 188           usage (EXIT_FAILURE);
 189         }
 190       context = argv[optind++];
 191     }
 192
 193   if (optind >= argc)
 194     {
 195       error (0, 0, _("no command specified"));
 196       usage (EXIT_FAILURE);
 197     }
 198
 199   if (is_selinux_enabled () != 1)
 200     error (EXIT_FAILURE, 0, _("%s may be used only on a SELinux kernel"),
 201            program_name);
 202
 203   if (context)
 204     {
 205       con = context_new (context);
 206       if (!con)
 207         error (EXIT_FAILURE, errno, _("failed to create security context: %s"),
 208                quotearg_colon (context));
 209     }
 210   else
 211     {
 212       if (getcon (&cur_context) < 0)
 213         error (EXIT_FAILURE, errno, _("failed to get current context"));
 214
 215       /* We will generate context based on process transition */
 216       if (compute_trans)
 217         {
 218           /* Get context of file to be executed */
 219           if (getfilecon (argv[optind], &file_context) == -1)
 220             error (EXIT_FAILURE, errno,
 221                    _("failed to get security context of %s"),
 222                    quote (argv[optind]));
 223           /* compute result of process transition */
 224           if (security_compute_create (cur_context, file_context,
 225                                        SECCLASS_PROCESS, &new_context) != 0)
 226             error (EXIT_FAILURE, errno, _("failed to compute a new context"));
 227           /* free contexts */
 228           freecon (file_context);
 229           freecon (cur_context);
 230
 231           /* set cur_context equal to new_context */
 232           cur_context = new_context;
 233         }
 234
 235       con = context_new (cur_context);
 236       if (!con)
 237         error (EXIT_FAILURE, errno, _("failed to create security context: %s"),
 238                quotearg_colon (cur_context));
 239       if (user && context_user_set (con, user))
 240         error (EXIT_FAILURE, errno, _("failed to set new user %s"), user);
 241       if (type && context_type_set (con, type))
 242         error (EXIT_FAILURE, errno, _("failed to set new type %s"), type);
 243       if (range && context_range_set (con, range))
 244         error (EXIT_FAILURE, errno, _("failed to set new range %s"), range);
 245       if (role && context_role_set (con, role))
 246         error (EXIT_FAILURE, errno, _("failed to set new role %s"), role);
 247     }
 248
 249   if (security_check_context (context_str (con)) < 0)
 250     error (EXIT_FAILURE, errno, _("invalid context: %s"),
 251            quotearg_colon (context_str (con)));
 252
 253   if (setexeccon (context_str (con)) != 0)
 254     error (EXIT_FAILURE, errno, _("unable to set security context %s"),
 255            quote (context_str (con)));
 256   if (cur_context != NULL)
 257     freecon (cur_context);
 258
 259   execvp (argv[optind], argv + optind);
 260
 261   {
 262     int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
 263     error (0, errno, "%s", argv[optind]);
 264     exit (exit_status);
 265   }
 266 }