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/* vi: set sw=4 ts=4: */
/*
* Mini su implementation for busybox
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
#include "libbb.h"
#include <syslog.h>
#define SU_OPT_mp (3)
#define SU_OPT_l (4)
int su_main(int argc, char **argv);
int su_main(int argc, char **argv)
{
unsigned flags;
char *opt_shell = NULL;
char *opt_command = NULL;
const char *opt_username = "root";
struct passwd *pw;
uid_t cur_uid = getuid();
const char *tty;
char *old_user;
flags = getopt32(argc, argv, "mplc:s:", &opt_command, &opt_shell);
argc -= optind;
argv += optind;
if (argc && LONE_DASH(argv[0])) {
flags |= SU_OPT_l;
argc--;
argv++;
}
/* get user if specified */
if (argc) {
opt_username = argv[0];
// argc--;
argv++;
}
if (ENABLE_FEATURE_SU_SYSLOG) {
/* The utmp entry (via getlogin) is probably the best way to identify
the user, especially if someone su's from a su-shell.
But getlogin can fail -- usually due to lack of utmp entry.
in this case resort to getpwuid. */
old_user = xstrdup(USE_FEATURE_UTMP(getlogin() ? : ) (pw = getpwuid(cur_uid)) ? pw->pw_name : "");
tty = ttyname(2) ? : "none";
openlog(applet_name, 0, LOG_AUTH);
}
pw = getpwnam(opt_username);
if (!pw)
bb_error_msg_and_die("unknown id: %s", 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)) {
if (ENABLE_FEATURE_SU_SYSLOG)
syslog(LOG_NOTICE, "%c %s %s:%s",
'+', tty, old_user, opt_username);
} else {
if (ENABLE_FEATURE_SU_SYSLOG)
syslog(LOG_NOTICE, "%c %s %s:%s",
'-', tty, old_user, opt_username);
bb_error_msg_and_die("incorrect password");
}
if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) {
closelog();
free(old_user);
}
if (!opt_shell && (flags & SU_OPT_mp))
opt_shell = getenv("SHELL");
#if ENABLE_FEATURE_SU_CHECKS_SHELLS
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. */
bb_error_msg("using restricted shell");
opt_shell = 0;
}
#endif
if (!opt_shell)
opt_shell = pw->pw_shell;
change_identity(pw);
setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw);
USE_SELINUX(set_current_security_context(NULL);)
/* Never returns */
run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv);
return EXIT_FAILURE;
}
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