1 /* vi: set sw=4 ts=4: */
3 * Mini su implementation for busybox
5 * Licensed under the GPL v2, see the file LICENSE in this tarball.
11 #include <sys/resource.h>
15 int su_main ( int argc, char **argv )
19 char *opt_command = 0;
20 char *opt_username = "root";
23 uid_t cur_uid = getuid();
27 flags = bb_getopt_ulflags(argc, argv, "mplc:s:", &opt_command, &opt_shell);
31 if (optind < argc && argv[optind][0] == '-' && argv[optind][1] == 0) {
36 /* get user if specified */
37 if (optind < argc) opt_username = argv [optind++];
39 if (optind < argc) opt_args = argv + optind;
41 if (ENABLE_SU_SYSLOG) {
42 /* The utmp entry (via getlogin) is probably the best way to identify
43 the user, especially if someone su's from a su-shell.
44 But getlogin can fail -- usually due to lack of utmp entry.
45 in this case resort to getpwuid. */
46 old_user = bb_xstrdup(USE_FEATURE_UTMP(getlogin() ? : ) (pw = getpwuid(cur_uid)) ? pw->pw_name : "");
47 tty = ttyname(2) ? : "none";
48 openlog(bb_applet_name, 0, LOG_AUTH);
51 pw = getpwnam(opt_username);
52 if (!pw) bb_error_msg_and_die("Unknown id: %s", opt_username);
54 /* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER
55 is a username that is retrieved via NIS (YP), but that doesn't have
56 a default shell listed. */
57 if (!pw->pw_shell || !pw->pw_shell[0]) pw->pw_shell = (char *)DEFAULT_SHELL;
59 if ((cur_uid == 0) || correct_password(pw)) {
61 syslog(LOG_NOTICE, "+ %s %s:%s", tty, old_user, opt_username);
64 syslog(LOG_NOTICE, "- %s %s:%s", tty, old_user, opt_username);
65 bb_error_msg_and_die("incorrect password");
68 if (ENABLE_FEATURE_CLEAN_UP && ENABLE_SU_SYSLOG) {
73 if (!opt_shell && (flags & SU_OPT_mp)) opt_shell = getenv("SHELL");
75 if (opt_shell && cur_uid && restricted_shell(pw->pw_shell)) {
76 /* The user being su'd to has a nonstandard shell, and so is
77 probably a uucp account or has restricted access. Don't
78 compromise the account by allowing access with a standard
80 bb_error_msg("using restricted shell");
84 if (!opt_shell) opt_shell = pw->pw_shell;
87 setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw);
88 USE_SELINUX(set_current_security_context(NULL);)
91 run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)opt_args);