git.maemo.org Git - busybox4maemo/blob - loginutils/sulogin.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini sulogin implementation for busybox
   4  *
   5  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   6  */
   7
   8 #include "libbb.h"
   9 #include <syslog.h>
  10
  11 //static void catchalarm(int ATTRIBUTE_UNUSED junk)
  12 //{
  13 //      exit(EXIT_FAILURE);
  14 //}
  15
  16
  17 int sulogin_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  18 int sulogin_main(int argc ATTRIBUTE_UNUSED, char **argv)
  19 {
  20         char *cp;
  21         int timeout = 0;
  22         struct passwd *pwd;
  23         const char *shell;
  24 #if ENABLE_FEATURE_SHADOWPASSWDS
  25         /* Using _r function to avoid pulling in static buffers */
  26         char buffer[256];
  27         struct spwd spw;
  28 #endif
  29
  30         logmode = LOGMODE_BOTH;
  31         openlog(applet_name, 0, LOG_AUTH);
  32
  33         opt_complementary = "t+"; /* -t N */
  34         getopt32(argv, "t:", &timeout);
  35
  36         if (argv[optind]) {
  37                 close(0);
  38                 close(1);
  39                 dup(xopen(argv[optind], O_RDWR));
  40                 close(2);
  41                 dup(0);
  42         }
  43
  44         /* Malicious use like "sulogin /dev/sda"? */
  45         if (!isatty(0) || !isatty(1) || !isatty(2)) {
  46                 logmode = LOGMODE_SYSLOG;
  47                 bb_error_msg_and_die("not a tty");
  48         }
  49
  50         /* Clear dangerous stuff, set PATH */
  51         sanitize_env_if_suid();
  52
  53 // bb_askpass() already handles this
  54 //      signal(SIGALRM, catchalarm);
  55
  56         pwd = getpwuid(0);
  57         if (!pwd) {
  58                 goto auth_error;
  59         }
  60
  61 #if ENABLE_FEATURE_SHADOWPASSWDS
  62         {
  63                 /* getspnam_r may return 0 yet set result to NULL.
  64                  * At least glibc 2.4 does this. Be extra paranoid here. */
  65                 struct spwd *result = NULL;
  66                 int r = getspnam_r(pwd->pw_name, &spw, buffer, sizeof(buffer), &result);
  67                 if (r || !result) {
  68                         goto auth_error;
  69                 }
  70                 pwd->pw_passwd = result->sp_pwdp;
  71         }
  72 #endif
  73
  74         while (1) {
  75                 /* cp points to a static buffer that is zeroed every time */
  76                 cp = bb_askpass(timeout,
  77                                 "Give root password for system maintenance\n"
  78                                 "(or type Control-D for normal startup):");
  79
  80                 if (!cp || !*cp) {
  81                         bb_info_msg("Normal startup");
  82                         return 0;
  83                 }
  84                 if (strcmp(pw_encrypt(cp, pwd->pw_passwd), pwd->pw_passwd) == 0) {
  85                         break;
  86                 }
  87                 bb_do_delay(FAIL_DELAY);
  88                 bb_error_msg("login incorrect");
  89         }
  90         memset(cp, 0, strlen(cp));
  91 //      signal(SIGALRM, SIG_DFL);
  92
  93         bb_info_msg("System Maintenance Mode");
  94
  95         USE_SELINUX(renew_current_security_context());
  96
  97         shell = getenv("SUSHELL");
  98         if (!shell)
  99                 shell = getenv("sushell");
 100         if (!shell) {
 101                 shell = "/bin/sh";
 102                 if (pwd->pw_shell[0])
 103                         shell = pwd->pw_shell;
 104         }
 105         /* Exec login shell with no additional parameters. Never returns. */
 106         run_shell(shell, 1, NULL, NULL);
 107
 108  auth_error:
 109         bb_error_msg_and_die("no password entry for root");
 110 }