/* vi: set sw=4 ts=4: */
/*
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Mini sulogin implementation for busybox
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
+//config:config SULOGIN
+//config: bool "sulogin (17 kb)"
+//config: default y
+//config: select FEATURE_SYSLOG
+//config: help
+//config: sulogin is invoked when the system goes into single user
+//config: mode (this is done through an entry in inittab).
-#include <fcntl.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <syslog.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"
-
-
-#define SULOGIN_PROMPT "\nGive root password for system maintenance\n" \
- "(or type Control-D for normal startup):"
-
-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);
-}
+//applet:IF_SULOGIN(APPLET_NOEXEC(sulogin, sulogin, BB_DIR_SBIN, BB_SUID_DROP, sulogin))
+//kbuild:lib-$(CONFIG_SULOGIN) += sulogin.o
-int sulogin_main(int argc, char **argv)
-{
- char *cp;
- char *device = NULL;
- const char *name = "root";
- int timeout = 0;
+//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"
-#define pass bb_common_bufsiz1
+#include "libbb.h"
+#include <syslog.h>
- struct passwd pwent;
+int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int sulogin_main(int argc UNUSED_PARAM, char **argv)
+{
+ int timeout = 0;
struct passwd *pwd;
- const char * const *p;
-#if ENABLE_FEATURE_SHADOWPASSWDS
- struct spwd *spwd = NULL;
-#endif
+ const char *shell;
+
+ /* Note: sulogin is not a suid app. It is meant to be run by init
+ * for single user / emergency mode. init starts it as root.
+ * Normal users (potentially malicious ones) can only run it under
+ * their UID, therefore no paranoia here is warranted:
+ * $LD_LIBRARY_PATH in env, TTY = /dev/sda
+ * are no more dangerous here than in e.g. cp applet.
+ */
- openlog("sulogin", LOG_PID | LOG_NOWAIT, LOG_AUTH);
logmode = LOGMODE_BOTH;
- if (argc > 1) {
- if (strncmp(argv[1], "-t", 2) == 0) {
- if (argv[1][2] == '\0') { /* -t NN */
- if (argc > 2) {
- timeout = atoi(argv[2]);
- if (argc > 3) {
- device = argv[3];
- }
- }
- } else { /* -tNNN */
- timeout = atoi(&argv[1][2]);
- if (argc > 2) {
- device = argv[2];
- }
- }
- } else {
- device = argv[1];
- }
- if (device) {
- close(0);
- close(1);
- close(2);
- if (open(device, O_RDWR) == 0) {
- dup(0);
- dup(0);
- } else {
- /* Well, it will go only to syslog :) */
- bb_perror_msg_and_die("Cannot open %s", device);
- }
- }
- }
- if (!isatty(0) || !isatty(1) || !isatty(2)) {
- exit(EXIT_FAILURE);
- }
- if (access(bb_path_passwd_file, 0) == -1) {
- bb_error_msg_and_die("No password file");
- }
+ openlog(applet_name, 0, LOG_AUTH);
- /* Clear out anything dangerous from the environment */
- for (p = forbid; *p; p++)
- unsetenv(*p);
+ getopt32(argv, "t:+", &timeout);
+ argv += optind;
- signal(SIGALRM, catchalarm);
- if (!(pwd = getpwnam(name))) {
- bb_error_msg_and_die("No password entry for `root'");
+ if (argv[0]) {
+ close(0);
+ close(1);
+ dup(xopen(argv[0], O_RDWR));
+ close(2);
+ dup(0);
}
- pwent = *pwd;
-#if ENABLE_FEATURE_SHADOWPASSWDS
- spwd = NULL;
- if (pwd && ((strcmp(pwd->pw_passwd, "x") == 0)
- || (strcmp(pwd->pw_passwd, "*") == 0))) {
- endspent();
- spwd = getspnam(name);
- if (spwd) {
- pwent.pw_passwd = spwd->sp_pwdp;
- }
+
+ pwd = getpwuid(0);
+ if (!pwd) {
+ bb_error_msg_and_die("no password entry for root");
}
-#endif
+
while (1) {
- cp = bb_askpass(timeout, SULOGIN_PROMPT);
- if (!cp || !*cp) {
- puts("\n"); /* Why only on error path? */
- fflush(stdout);
- /* Why only to syslog? */
- syslog(LOG_INFO, "Normal startup");
- exit(EXIT_SUCCESS);
- } else {
- safe_strncpy(pass, cp, sizeof(pass));
- memset(cp, 0, strlen(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_error_msg("normal startup");
+ return 0;
}
- if (strcmp(pw_encrypt(pass, pwent.pw_passwd), pwent.pw_passwd) == 0) {
+ if (r > 0) {
break;
}
- bb_do_delay(FAIL_DELAY);
- bb_error_msg("Incorrect root password");
+ bb_do_delay(LOGIN_FAIL_DELAY);
+ bb_error_msg("Login incorrect");
}
- memset(pass, 0, strlen(pass));
- signal(SIGALRM, SIG_DFL);
- bb_info_msg("Entering System Maintenance Mode");
-#if ENABLE_SELINUX
- renew_current_security_context();
-#endif
+ bb_error_msg("starting shell for system maintenance");
+
+ IF_SELINUX(renew_current_security_context());
- run_shell(pwent.pw_shell, 1, 0, 0);
+ shell = getenv("SUSHELL");
+ if (!shell)
+ shell = getenv("sushell");
+ if (!shell)
+ shell = pwd->pw_shell;
- return 0;
+ /* Exec login shell with no additional parameters. Never returns. */
+ run_shell(shell, 1, NULL);
}
projects / oweals / busybox.git / blobdiff