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/* vi: set sw=4 ts=4: */
/*
Licensed under the GPL v2, see the file LICENSE in this tarball.
*/
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <termios.h>
#include <unistd.h>
#include <utmp.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <ctype.h>
#include <time.h>
#include "busybox.h"
/* The shell to run if none is given in the user's passwd entry. */
#ifndef DEFAULT_SHELL
#define DEFAULT_SHELL "/bin/sh"
#endif
/* Default user. */
#define DEFAULT_USER "root"
/* #define SYSLOG_SUCCESS */
#define SYSLOG_FAILURE
#if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
/* Log the fact that someone has run su */
# if defined( SYSLOG_SUCCESS ) && defined( SYSLOG_FAILURE )
static void log_su (const char *successful, const char *old_user,
const char *tty)
{
syslog ( LOG_NOTICE, "%s%s on %s", successful, old_user, tty);
}
# define log_su_successful(cu, u, tty) if(!cu) log_su("", u, tty)
# define log_su_failure(cu, u, tty) if(!cu) log_su("FAILED SU ", u, tty)
# else
/* partial logging */
# if !defined( SYSLOG_SUCESS )
# define log_su_successful(cu, u, tty)
# define log_su_failure(cu, u, t) if(!cu) \
syslog(LOG_NOTICE, "FAILED SU %s on %s", u, t)
# else
# define log_su_successful(cu, u, t) if(!cu) \
syslog(LOG_NOTICE, "%s on %s", u, t)
# define log_su_failure(cu, u, tty)
# endif
# endif
#else
/* logging not used */
# define log_su_successful(cu, u, tty)
# define log_su_failure(cu, u, tty)
#endif
int su_main ( int argc, char **argv )
{
unsigned long flags;
char *opt_shell = 0;
char *opt_command = 0;
char *opt_username = DEFAULT_USER;
char **opt_args = 0;
struct passwd *pw;
uid_t cur_uid = getuid();
#if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
const char *tty;
const char *old_user;
#endif
flags = bb_getopt_ulflags(argc, argv, "mplc:s:",
&opt_command, &opt_shell);
#define SU_OPT_m (3)
#define SU_OPT_p (3)
#define SU_OPT_l (4)
if (optind < argc && argv[optind][0] == '-' && argv[optind][1] == 0) {
flags |= SU_OPT_l;
++optind;
}
/* get user if specified */
if ( optind < argc )
opt_username = argv [optind++];
if ( optind < argc )
opt_args = argv + optind;
#if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
#ifdef CONFIG_FEATURE_UTMP
/* The utmp entry (via getlogin) is probably the best way to identify
the user, especially if someone su's from a su-shell. */
old_user = getlogin ( );
if ( !old_user )
#endif
{
/* getlogin can fail -- usually due to lack of utmp entry.
Resort to getpwuid. */
pw = getpwuid ( cur_uid );
old_user = ( pw ? pw->pw_name : "" );
}
tty = ttyname ( 2 );
if(!tty)
tty = "none";
openlog ( bb_applet_name, 0, LOG_AUTH );
#endif
pw = getpwnam ( opt_username );
if ( !pw )
bb_error_msg_and_die ( "user %s does not exist", opt_username );
/* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER
is a username that is retrieved via NIS (YP), but that doesn't have
a default shell listed. */
if ( !pw->pw_shell || !pw->pw_shell [0] )
pw->pw_shell = (char *) DEFAULT_SHELL;
if ((( cur_uid == 0 ) || correct_password ( pw ))) {
log_su_successful(pw->pw_uid, old_user, tty );
} else {
log_su_failure (pw->pw_uid, old_user, tty );
bb_error_msg_and_die ( "incorrect password" );
}
#if defined( SYSLOG_SUCCESS ) || defined( SYSLOG_FAILURE )
closelog();
#endif
if ( !opt_shell && (flags & SU_OPT_p))
opt_shell = getenv ( "SHELL" );
if ( opt_shell && cur_uid && restricted_shell ( pw->pw_shell )) {
/* The user being su'd to has a nonstandard shell, and so is
probably a uucp account or has restricted access. Don't
compromise the account by allowing access with a standard
shell. */
fputs ( "using restricted shell\n", stderr );
opt_shell = 0;
}
if ( !opt_shell )
opt_shell = pw->pw_shell;
change_identity ( pw );
setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_p), pw);
#if ENABLE_SELINUX
set_current_security_context(NULL);
#endif
run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)opt_args);
return EXIT_FAILURE;
}
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