/*
* Mini sulogin implementation for busybox
*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
-#include <syslog.h>
+//usage:#define sulogin_trivial_usage
+//usage: "[-t N] [TTY]"
+//usage:#define sulogin_full_usage "\n\n"
+//usage: "Single user login\n"
+//usage: "\n -t N Timeout"
#include "libbb.h"
+#include <syslog.h>
-static const char *const forbid[] = {
- "ENV",
- "BASH_ENV",
- "HOME",
- "IFS",
- "PATH",
- "SHELL",
- "LD_LIBRARY_PATH",
- "LD_PRELOAD",
- "LD_TRACE_LOADED_OBJECTS",
- "LD_BIND_NOW",
- "LD_AOUT_LIBRARY_PATH",
- "LD_AOUT_PRELOAD",
- "LD_NOWARN",
- "LD_KEEPDIR",
- (char *) 0
-};
-
-
-static void catchalarm(int ATTRIBUTE_UNUSED junk)
-{
- exit(EXIT_FAILURE);
-}
-
-
-int sulogin_main(int argc, char **argv);
-int sulogin_main(int argc, char **argv)
+int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int sulogin_main(int argc UNUSED_PARAM, char **argv)
{
- char *cp;
int timeout = 0;
- char *timeout_arg;
- const char *const *p;
struct passwd *pwd;
const char *shell;
-#if ENABLE_FEATURE_SHADOWPASSWDS
- /* Using _r function to avoid pulling in static buffers */
- char buffer[256];
- struct spwd spw;
- struct spwd *result;
-#endif
logmode = LOGMODE_BOTH;
openlog(applet_name, 0, LOG_AUTH);
- if (getopt32(argc, argv, "t:", &timeout_arg)) {
- timeout = xatoi_u(timeout_arg);
- }
+ opt_complementary = "t+"; /* -t N */
+ getopt32(argv, "t:", &timeout);
+ argv += optind;
- if (argv[optind]) {
+ if (argv[0]) {
close(0);
close(1);
- dup(xopen(argv[optind], O_RDWR));
+ dup(xopen(argv[0], O_RDWR));
close(2);
dup(0);
}
+ /* Malicious use like "sulogin /dev/sda"? */
if (!isatty(0) || !isatty(1) || !isatty(2)) {
logmode = LOGMODE_SYSLOG;
bb_error_msg_and_die("not a tty");
}
- /* Clear out anything dangerous from the environment */
- for (p = forbid; *p; p++)
- unsetenv(*p);
-
- signal(SIGALRM, catchalarm);
+ /* Clear dangerous stuff, set PATH */
+ sanitize_env_if_suid();
pwd = getpwuid(0);
if (!pwd) {
goto auth_error;
}
-#if ENABLE_FEATURE_SHADOWPASSWDS
- if (getspnam_r(pwd->pw_name, &spw, buffer, sizeof(buffer), &result)) {
- goto auth_error;
- }
- pwd->pw_passwd = spw.sp_pwdp;
-#endif
-
while (1) {
- /* cp points to a static buffer that is zeroed every time */
- cp = bb_askpass(timeout,
- "Give root password for system maintenance\n"
- "(or type Control-D for normal startup):");
-
- if (!cp || !*cp) {
+ int r;
+
+ r = ask_and_check_password_extended(pwd, timeout,
+ "Give root password for system maintenance\n"
+ "(or type Control-D for normal startup):"
+ );
+ if (r < 0) {
+ /* ^D, ^C, timeout, or read error */
bb_info_msg("Normal startup");
return 0;
}
- if (strcmp(pw_encrypt(cp, pwd->pw_passwd), pwd->pw_passwd) == 0) {
+ if (r > 0) {
break;
}
- bb_do_delay(FAIL_DELAY);
- bb_error_msg("login incorrect");
+ bb_do_delay(LOGIN_FAIL_DELAY);
+ bb_info_msg("Login incorrect");
}
- memset(cp, 0, strlen(cp));
- signal(SIGALRM, SIG_DFL);
bb_info_msg("System Maintenance Mode");
- USE_SELINUX(renew_current_security_context());
+ IF_SELINUX(renew_current_security_context());
shell = getenv("SUSHELL");
- if (!shell) shell = getenv("sushell");
- if (!shell) {
- shell = "/bin/sh";
- if (pwd->pw_shell[0])
- shell = pwd->pw_shell;
- }
- run_shell(shell, 1, 0, 0);
- /* never returns */
+ if (!shell)
+ shell = getenv("sushell");
+ if (!shell)
+ shell = pwd->pw_shell;
+
+ /* Exec login shell with no additional parameters. Never returns. */
+ run_shell(shell, 1, NULL, NULL);
-auth_error:
- bb_error_msg_and_die("no password entry for 'root'");
+ auth_error:
+ bb_error_msg_and_die("no password entry for root");
}