1 /* vi: set sw=4 ts=4: */
3 * Mini su implementation for busybox
5 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
14 int su_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
15 int su_main(int argc UNUSED_PARAM, char **argv)
18 char *opt_shell = NULL;
19 char *opt_command = NULL;
20 const char *opt_username = "root";
22 uid_t cur_uid = getuid();
26 flags = getopt32(argv, "mplc:s:", &opt_command, &opt_shell);
30 if (argv[0] && LONE_DASH(argv[0])) {
35 /* get user if specified */
37 opt_username = argv[0];
41 if (ENABLE_FEATURE_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. */
47 #if ENABLE_FEATURE_UTMP
50 if (getlogin_r(user_buf, sizeof(user_buf)) != 0)
53 pw = getpwuid(cur_uid);
54 user = pw ? pw->pw_name : "";
56 old_user = xstrdup(user);
57 tty = xmalloc_ttyname(2);
61 openlog(applet_name, 0, LOG_AUTH);
64 pw = xgetpwnam(opt_username);
66 /* Make sure pw->pw_shell is non-NULL. It may be NULL when NEW_USER
67 is a username that is retrieved via NIS (YP), but that doesn't have
68 a default shell listed. */
69 if (!pw->pw_shell || !pw->pw_shell[0])
70 pw->pw_shell = (char *)DEFAULT_SHELL;
72 if ((cur_uid == 0) || correct_password(pw)) {
73 if (ENABLE_FEATURE_SU_SYSLOG)
74 syslog(LOG_NOTICE, "%c %s %s:%s",
75 '+', tty, old_user, opt_username);
77 if (ENABLE_FEATURE_SU_SYSLOG)
78 syslog(LOG_NOTICE, "%c %s %s:%s",
79 '-', tty, old_user, opt_username);
80 bb_error_msg_and_die("incorrect password");
83 if (ENABLE_FEATURE_CLEAN_UP && ENABLE_FEATURE_SU_SYSLOG) {
88 if (!opt_shell && (flags & SU_OPT_mp))
89 opt_shell = getenv("SHELL");
91 #if ENABLE_FEATURE_SU_CHECKS_SHELLS
92 if (opt_shell && cur_uid && restricted_shell(pw->pw_shell)) {
93 /* The user being su'd to has a nonstandard shell, and so is
94 probably a uucp account or has restricted access. Don't
95 compromise the account by allowing access with a standard
97 bb_error_msg("using restricted shell");
102 opt_shell = pw->pw_shell;
105 /* setup_environment params: shell, clear_env, change_env, pw */
106 setup_environment(opt_shell, flags & SU_OPT_l, !(flags & SU_OPT_mp), pw);
107 IF_SELINUX(set_current_security_context(NULL);)
110 run_shell(opt_shell, flags & SU_OPT_l, opt_command, (const char**)argv);
112 /* return EXIT_FAILURE; - not reached */