src/runcon.c

   1 /* runcon -- run command with specified security context
   2    Copyright (C) 2005-2024 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 <https://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 #include <sys/types.h>
  49 #include "system.h"
  50 #include "quote.h"
  51
  52 /* The official name of this program (e.g., no 'g' prefix).  */
  53 #define PROGRAM_NAME "runcon"
  54
  55 #define AUTHORS proper_name ("Russell Coker")
  56
  57 static struct option const long_options[] =
  58 {
  59   {"role", required_argument, nullptr, 'r'},
  60   {"type", required_argument, nullptr, 't'},
  61   {"user", required_argument, nullptr, 'u'},
  62   {"range", required_argument, nullptr, 'l'},
  63   {"compute", no_argument, nullptr, 'c'},
  64   {GETOPT_HELP_OPTION_DECL},
  65   {GETOPT_VERSION_OPTION_DECL},
  66   {nullptr, 0, nullptr, 0}
  67 };
  68
  69 void
  70 usage (int status)
  71 {
  72   if (status != EXIT_SUCCESS)
  73     emit_try_help ();
  74   else
  75     {
  76       printf (_("\
  77 Usage: %s CONTEXT COMMAND [args]\n\
  78   or:  %s [ -c ] [-u USER] [-r ROLE] [-t TYPE] [-l RANGE] COMMAND [args]\n\
  79 "), program_name, program_name);
  80       fputs (_("\
  81 Run a program in a different SELinux security context.\n\
  82 With neither CONTEXT nor COMMAND, print the current security context.\n\
  83 "), stdout);
  84
  85       emit_mandatory_arg_note ();
  86
  87       fputs (_("\
  88   CONTEXT            Complete security context\n\
  89   -c, --compute      compute process transition context before modifying\n\
  90   -t, --type=TYPE    type (for same role as parent)\n\
  91   -u, --user=USER    user identity\n\
  92   -r, --role=ROLE    role\n\
  93   -l, --range=RANGE  levelrange\n\
  94 "), stdout);
  95       fputs (HELP_OPTION_DESCRIPTION, stdout);
  96       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  97       emit_exec_status (PROGRAM_NAME);
  98       emit_ancillary_info (PROGRAM_NAME);
  99     }
 100   exit (status);
 101 }
 102
 103 int
 104 main (int argc, char **argv)
 105 {
 106   char *role = nullptr;
 107   char *range = nullptr;
 108   char *user = nullptr;
 109   char *type = nullptr;
 110   char *context = nullptr;
 111   char *cur_context = nullptr;
 112   char *file_context = nullptr;
 113   char *new_context = nullptr;
 114   bool compute_trans = false;
 115
 116   context_t con;
 117
 118   initialize_main (&argc, &argv);
 119   set_program_name (argv[0]);
 120   setlocale (LC_ALL, "");
 121   bindtextdomain (PACKAGE, LOCALEDIR);
 122   textdomain (PACKAGE);
 123
 124   initialize_exit_failure (EXIT_CANCELED);
 125   atexit (close_stdout);
 126
 127   while (true)
 128     {
 129       int option_index = 0;
 130       int c = getopt_long (argc, argv, "+r:t:u:l:c", long_options,
 131                            &option_index);
 132       if (c == -1)
 133         break;
 134       switch (c)
 135         {
 136         case 'r':
 137           if (role)
 138             error (EXIT_CANCELED, 0, _("multiple roles"));
 139           role = optarg;
 140           break;
 141         case 't':
 142           if (type)
 143             error (EXIT_CANCELED, 0, _("multiple types"));
 144           type = optarg;
 145           break;
 146         case 'u':
 147           if (user)
 148             error (EXIT_CANCELED, 0, _("multiple users"));
 149           user = optarg;
 150           break;
 151         case 'l':
 152           if (range)
 153             error (EXIT_CANCELED, 0, _("multiple levelranges"));
 154           range = optarg;
 155           break;
 156         case 'c':
 157           compute_trans = true;
 158           break;
 159
 160         case_GETOPT_HELP_CHAR;
 161         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 162         default:
 163           usage (EXIT_CANCELED);
 164           break;
 165         }
 166     }
 167
 168   if (argc - optind == 0)
 169     {
 170       if (getcon (&cur_context) < 0)
 171         error (EXIT_CANCELED, errno, _("failed to get current context"));
 172       fputs (cur_context, stdout);
 173       fputc ('\n', stdout);
 174       return EXIT_SUCCESS;
 175     }
 176
 177   if (!(user || role || type || range || compute_trans))
 178     {
 179       if (optind >= argc)
 180         {
 181           error (0, 0, _("you must specify -c, -t, -u, -l, -r, or context"));
 182           usage (EXIT_CANCELED);
 183         }
 184       context = argv[optind++];
 185     }
 186
 187   if (optind >= argc)
 188     {
 189       error (0, 0, _("no command specified"));
 190       usage (EXIT_CANCELED);
 191     }
 192
 193   if (is_selinux_enabled () != 1)
 194     error (EXIT_CANCELED, 0, _("%s may be used only on a SELinux kernel"),
 195            program_name);
 196
 197   if (context)
 198     {
 199       con = context_new (context);
 200       if (!con)
 201         error (EXIT_CANCELED, errno, _("failed to create security context: %s"),
 202                quote (context));
 203     }
 204   else
 205     {
 206       if (getcon (&cur_context) < 0)
 207         error (EXIT_CANCELED, errno, _("failed to get current context"));
 208
 209       /* We will generate context based on process transition */
 210       if (compute_trans)
 211         {
 212           /* Get context of file to be executed */
 213           if (getfilecon (argv[optind], &file_context) == -1)
 214             error (EXIT_CANCELED, errno,
 215                    _("failed to get security context of %s"),
 216                    quoteaf (argv[optind]));
 217           /* compute result of process transition */
 218           if (security_compute_create (cur_context, file_context,
 219                                        string_to_security_class ("process"),
 220                                        &new_context) != 0)
 221             error (EXIT_CANCELED, errno, _("failed to compute a new context"));
 222           /* free contexts */
 223           freecon (file_context);
 224           freecon (cur_context);
 225
 226           /* set cur_context equal to new_context */
 227           cur_context = new_context;
 228         }
 229
 230       con = context_new (cur_context);
 231       if (!con)
 232         error (EXIT_CANCELED, errno, _("failed to create security context: %s"),
 233                quote (cur_context));
 234       if (user && context_user_set (con, user))
 235         error (EXIT_CANCELED, errno, _("failed to set new user: %s"),
 236                quote (user));
 237       if (type && context_type_set (con, type))
 238         error (EXIT_CANCELED, errno, _("failed to set new type: %s"),
 239                quote (type));
 240       if (range && context_range_set (con, range))
 241         error (EXIT_CANCELED, errno, _("failed to set new range: %s"),
 242                quote (range));
 243       if (role && context_role_set (con, role))
 244         error (EXIT_CANCELED, errno, _("failed to set new role: %s"),
 245                quote (role));
 246     }
 247
 248   if (security_check_context (context_str (con)) < 0)
 249     error (EXIT_CANCELED, errno, _("invalid context: %s"),
 250            quote (context_str (con)));
 251
 252   if (setexeccon (context_str (con)) != 0)
 253     error (EXIT_CANCELED, errno, _("unable to set security context %s"),
 254            quote (context_str (con)));
 255   if (cur_context != nullptr)
 256     freecon (cur_context);
 257
 258   (compute_trans ? execv : execvp) (argv[optind], argv + optind);
 259
 260   int exit_status = errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE;
 261   error (0, errno, "%s", quote (argv[optind]));
 262   return exit_status;
 263 }