source: MondoRescue/branches/3.2/mindi-busybox/selinux/runcon.c

/*
 * runcon [ context |
 *         ( [ -c ] [ -r role ] [-t type] [ -u user ] [ -l levelrange ] )
 *         command [arg1 [arg2 ...] ]
 *
 * attempt to run the specified command with the specified context.
 *
 * -r role  : use the current context with the specified role
 * -t type  : use the current context with the specified type
 * -u user  : use the current context with the specified user
 * -l level : use the current context with the specified level range
 * -c       : compute process transition context before modifying
 *
 * Contexts are interpreted as follows:
 *
 * Number of       MLS
 * components    system?
 *
 *     1            -         type
 *     2            -         role:type
 *     3            Y         role:type:range
 *     3            N         user:role:type
 *     4            Y         user:role:type:range
 *     4            N         error
 *
 * Port to busybox: KaiGai Kohei <kaigai@kaigai.gr.jp>
 *                  - based on coreutils-5.97 (in Fedora Core 6)
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

//usage:#define runcon_trivial_usage
//usage:       "[-c] [-u USER] [-r ROLE] [-t TYPE] [-l RANGE] PROG ARGS\n"
//usage:       "runcon CONTEXT PROG ARGS"
//usage:#define runcon_full_usage "\n\n"
//usage:       "Run PROG in a different security context\n"
//usage:     "\n    CONTEXT     Complete security context\n"
//usage:    IF_FEATURE_RUNCON_LONG_OPTIONS(
//usage:     "\n    -c,--compute    Compute process transition context before modifying"
//usage:     "\n    -t,--type=TYPE  Type (for same role as parent)"
//usage:     "\n    -u,--user=USER  User identity"
//usage:     "\n    -r,--role=ROLE  Role"
//usage:     "\n    -l,--range=RNG  Levelrange"
//usage:    )
//usage:    IF_NOT_FEATURE_RUNCON_LONG_OPTIONS(
//usage:     "\n    -c  Compute process transition context before modifying"
//usage:     "\n    -t TYPE Type (for same role as parent)"
//usage:     "\n    -u USER User identity"
//usage:     "\n    -r ROLE Role"
//usage:     "\n    -l RNG  Levelrange"
//usage:    )

#include <selinux/context.h>
#include <selinux/flask.h>

#include "libbb.h"

static context_t runcon_compute_new_context(char *user, char *role, char *type, char *range,
            char *command, int compute_trans)
{
    context_t con;
    security_context_t cur_context;

    if (getcon(&cur_context))
        bb_error_msg_and_die("can't get current context");

    if (compute_trans) {
        security_context_t file_context, new_context;

        if (getfilecon(command, &file_context) < 0)
            bb_error_msg_and_die("can't retrieve attributes of '%s'",
                    command);
        if (security_compute_create(cur_context, file_context,
                    SECCLASS_PROCESS, &new_context))
            bb_error_msg_and_die("unable to compute a new context");
        cur_context = new_context;
    }

    con = context_new(cur_context);
    if (!con)
        bb_error_msg_and_die("'%s' is not a valid context", cur_context);
    if (user && context_user_set(con, user))
        bb_error_msg_and_die("can't set new user '%s'", user);
    if (type && context_type_set(con, type))
        bb_error_msg_and_die("can't set new type '%s'", type);
    if (range && context_range_set(con, range))
        bb_error_msg_and_die("can't set new range '%s'", range);
    if (role && context_role_set(con, role))
        bb_error_msg_and_die("can't set new role '%s'", role);

    return con;
}

#if ENABLE_FEATURE_RUNCON_LONG_OPTIONS
static const char runcon_longopts[] ALIGN1 =
    "user\0"    Required_argument "u"
    "role\0"    Required_argument "r"
    "type\0"    Required_argument "t"
    "range\0"   Required_argument "l"
    "compute\0" No_argument "c"
    "help\0"    No_argument "h"
    ;
#endif

#define OPTS_ROLE   (1<<0)  /* r */
#define OPTS_TYPE   (1<<1)  /* t */
#define OPTS_USER   (1<<2)  /* u */
#define OPTS_RANGE  (1<<3)  /* l */
#define OPTS_COMPUTE    (1<<4)  /* c */
#define OPTS_HELP   (1<<5)  /* h */
#define OPTS_CONTEXT_COMPONENT      (OPTS_ROLE | OPTS_TYPE | OPTS_USER | OPTS_RANGE)

int runcon_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int runcon_main(int argc UNUSED_PARAM, char **argv)
{
    char *role = NULL;
    char *range = NULL;
    char *user = NULL;
    char *type = NULL;
    char *context = NULL;
    unsigned opts;
    context_t con;

    selinux_or_die();

#if ENABLE_FEATURE_RUNCON_LONG_OPTIONS
    applet_long_options = runcon_longopts;
#endif
    opt_complementary = "-1";
    opts = getopt32(argv, "r:t:u:l:ch", &role, &type, &user, &range);
    argv += optind;

    if (!(opts & OPTS_CONTEXT_COMPONENT)) {
        context = *argv++;
        if (!argv[0])
            bb_error_msg_and_die("no command given");
    }

    if (context) {
        con = context_new(context);
        if (!con)
            bb_error_msg_and_die("'%s' is not a valid context", context);
    } else {
        con = runcon_compute_new_context(user, role, type, range,
                argv[0], opts & OPTS_COMPUTE);
    }

    if (security_check_context(context_str(con)))
        bb_error_msg_and_die("'%s' is not a valid context",
                context_str(con));

    if (setexeccon(context_str(con)))
        bb_error_msg_and_die("can't set up security context '%s'",
                context_str(con));

    BB_EXECVP_or_die(argv);
}