LXR busybox/selinux/runcon.c

   1/*
   2 * runcon [ context |
   3 *         ( [ -c ] [ -r role ] [-t type] [ -u user ] [ -l levelrange ] )
   4 *         command [arg1 [arg2 ...] ]
   5 *
   6 * attempt to run the specified command with the specified context.
   7 *
   8 * -r role  : use the current context with the specified role
   9 * -t type  : use the current context with the specified type
  10 * -u user  : use the current context with the specified user
  11 * -l level : use the current context with the specified level range
  12 * -c       : compute process transition context before modifying
  13 *
  14 * Contexts are interpreted as follows:
  15 *
  16 * Number of       MLS
  17 * components    system?
  18 *
  19 *     1            -         type
  20 *     2            -         role:type
  21 *     3            Y         role:type:range
  22 *     3            N         user:role:type
  23 *     4            Y         user:role:type:range
  24 *     4            N         error
  25 *
  26 * Port to busybox: KaiGai Kohei <kaigai@kaigai.gr.jp>
  27 *                  - based on coreutils-5.97 (in Fedora Core 6)
  28 *
  29 * Licensed under GPLv2, see file LICENSE in this source tree.
  30 */
  31//config:config RUNCON
  32//config:       bool "runcon (6.6 kb)"
  33//config:       default n
  34//config:       depends on SELINUX
  35//config:       help
  36//config:       Enable support to run command in specified security context.
  37
  38//applet:IF_RUNCON(APPLET(runcon, BB_DIR_USR_BIN, BB_SUID_DROP))
  39
  40//kbuild:lib-$(CONFIG_RUNCON) += runcon.o
  41
  42//usage:#define runcon_trivial_usage
  43//usage:       "[-c] [-u USER] [-r ROLE] [-t TYPE] [-l RANGE] PROG ARGS\n"
  44//usage:       "runcon CONTEXT PROG ARGS"
  45//usage:#define runcon_full_usage "\n\n"
  46//usage:       "Run PROG in a different security context\n"
  47//usage:     "\n        CONTEXT         Complete security context\n"
  48//usage:     "\n        -c      Compute process transition context before modifying"
  49//usage:     "\n        -t TYPE Type (for same role as parent)"
  50//usage:     "\n        -u USER User identity"
  51//usage:     "\n        -r ROLE Role"
  52//usage:     "\n        -l RNG  Levelrange"
  53
  54#include <selinux/context.h>
  55/* from deprecated <selinux/flask.h>: */
  56#undef  SECCLASS_PROCESS
  57#define SECCLASS_PROCESS 2
  58
  59#include "libbb.h"
  60
  61static context_t runcon_compute_new_context(char *user, char *role, char *type, char *range,
  62                        char *command, int compute_trans)
  63{
  64        context_t con;
  65        security_context_t cur_context;
  66
  67        if (getcon(&cur_context))
  68                bb_error_msg_and_die("can't get current context");
  69
  70        if (compute_trans) {
  71                security_context_t file_context, new_context;
  72
  73                if (getfilecon(command, &file_context) < 0)
  74                        bb_error_msg_and_die("can't retrieve attributes of '%s'",
  75                                        command);
  76                if (security_compute_create(cur_context, file_context,
  77                                        SECCLASS_PROCESS, &new_context))
  78                        bb_error_msg_and_die("unable to compute a new context");
  79                cur_context = new_context;
  80        }
  81
  82        con = context_new(cur_context);
  83        if (!con)
  84                bb_error_msg_and_die("'%s' is not a valid context", cur_context);
  85        if (user && context_user_set(con, user))
  86                bb_error_msg_and_die("can't set new user '%s'", user);
  87        if (type && context_type_set(con, type))
  88                bb_error_msg_and_die("can't set new type '%s'", type);
  89        if (range && context_range_set(con, range))
  90                bb_error_msg_and_die("can't set new range '%s'", range);
  91        if (role && context_role_set(con, role))
  92                bb_error_msg_and_die("can't set new role '%s'", role);
  93
  94        return con;
  95}
  96
  97#if ENABLE_LONG_OPTS
  98static const char runcon_longopts[] ALIGN1 =
  99        "user\0"    Required_argument "u"
 100        "role\0"    Required_argument "r"
 101        "type\0"    Required_argument "t"
 102        "range\0"   Required_argument "l"
 103        "compute\0" No_argument "c"
 104        "help\0"    No_argument "h"
 105        ;
 106#endif
 107
 108#define OPTS_ROLE       (1<<0)  /* r */
 109#define OPTS_TYPE       (1<<1)  /* t */
 110#define OPTS_USER       (1<<2)  /* u */
 111#define OPTS_RANGE      (1<<3)  /* l */
 112#define OPTS_COMPUTE    (1<<4)  /* c */
 113#define OPTS_HELP       (1<<5)  /* h */
 114#define OPTS_CONTEXT_COMPONENT          (OPTS_ROLE | OPTS_TYPE | OPTS_USER | OPTS_RANGE)
 115
 116int runcon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 117int runcon_main(int argc UNUSED_PARAM, char **argv)
 118{
 119        char *role = NULL;
 120        char *range = NULL;
 121        char *user = NULL;
 122        char *type = NULL;
 123        char *context = NULL;
 124        unsigned opts;
 125        context_t con;
 126
 127        selinux_or_die();
 128
 129        opts = getopt32long(argv, "^"
 130                        "r:t:u:l:ch"
 131                        "\0" "-1",
 132                        runcon_longopts,
 133                        &role, &type, &user, &range
 134        );
 135        argv += optind;
 136
 137        if (!(opts & OPTS_CONTEXT_COMPONENT)) {
 138                context = *argv++;
 139                if (!argv[0])
 140                        bb_error_msg_and_die("no command given");
 141        }
 142
 143        if (context) {
 144                con = context_new(context);
 145                if (!con)
 146                        bb_error_msg_and_die("'%s' is not a valid context", context);
 147        } else {
 148                con = runcon_compute_new_context(user, role, type, range,
 149                                argv[0], opts & OPTS_COMPUTE);
 150        }
 151
 152        if (security_check_context(context_str(con)))
 153                bb_error_msg_and_die("'%s' is not a valid context",
 154                                context_str(con));
 155
 156        if (setexeccon(context_str(con)))
 157                bb_error_msg_and_die("can't set up security context '%s'",
 158                                context_str(con));
 159
 160        BB_EXECVP_or_die(argv);
 161}
 162