loginutils/sulogin.c

   1 /* vi: set sw=4 ts=4: */
   2 #include <fcntl.h>
   3 #include <signal.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <syslog.h>
   8 #include <termios.h>
   9 #include <unistd.h>
  10 #include <utmp.h>
  11 #include <sys/resource.h>
  12 #include <sys/stat.h>
  13 #include <sys/time.h>
  14 #include <sys/types.h>
  15 #include <ctype.h>
  16 #include <time.h>
  17
  18 #include "busybox.h"
  19
  20
  21 // sulogin defines
  22 #define SULOGIN_PROMPT "\nGive root password for system maintenance\n" \
  23         "(or type Control-D for normal startup):"
  24
  25 static const char *forbid[] = {
  26         "ENV",
  27         "BASH_ENV",
  28         "HOME",
  29         "IFS",
  30         "PATH",
  31         "SHELL",
  32         "LD_LIBRARY_PATH",
  33         "LD_PRELOAD",
  34         "LD_TRACE_LOADED_OBJECTS",
  35         "LD_BIND_NOW",
  36         "LD_AOUT_LIBRARY_PATH",
  37         "LD_AOUT_PRELOAD",
  38         "LD_NOWARN",
  39         "LD_KEEPDIR",
  40         (char *) 0
  41 };
  42
  43
  44
  45 static void catchalarm(int junk)
  46 {
  47         exit(EXIT_FAILURE);
  48 }
  49
  50
  51 extern int sulogin_main(int argc, char **argv)
  52 {
  53         char *cp;
  54         char *device = (char *) 0;
  55         const char *name = "root";
  56         int timeout = 0;
  57         static char pass[BUFSIZ];
  58         struct termios termio;
  59         struct passwd pwent;
  60         struct passwd *pwd;
  61         time_t start, now;
  62         const char **p;
  63 #ifdef CONFIG_FEATURE_SHADOWPASSWDS
  64         struct spwd *spwd = NULL;
  65 #endif                                                  /* CONFIG_FEATURE_SHADOWPASSWDS */
  66
  67         tcgetattr(0, &termio);
  68         /* set control chars */
  69         termio.c_cc[VINTR]  = 3;        /* C-c */
  70         termio.c_cc[VQUIT]  = 28;       /* C-\ */
  71         termio.c_cc[VERASE] = 127; /* C-? */
  72         termio.c_cc[VKILL]  = 21;       /* C-u */
  73         termio.c_cc[VEOF]   = 4;        /* C-d */
  74         termio.c_cc[VSTART] = 17;       /* C-q */
  75         termio.c_cc[VSTOP]  = 19;       /* C-s */
  76         termio.c_cc[VSUSP]  = 26;       /* C-z */
  77         /* use line dicipline 0 */
  78         termio.c_line = 0;
  79         /* Make it be sane */
  80         termio.c_cflag &= CBAUD|CBAUDEX|CSIZE|CSTOPB|PARENB|PARODD;
  81         termio.c_cflag |= CREAD|HUPCL|CLOCAL;
  82         /* input modes */
  83         termio.c_iflag = ICRNL | IXON | IXOFF;
  84         /* output modes */
  85         termio.c_oflag = OPOST | ONLCR;
  86         /* local modes */
  87         termio.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | ECHOKE | IEXTEN;
  88         tcsetattr(0, TCSANOW, &termio);
  89         openlog("sulogin", LOG_PID | LOG_CONS | LOG_NOWAIT, LOG_AUTH);
  90         if (argc > 1) {
  91                 if (strncmp(argv[1], "-t", 2) == 0) {
  92                         if (strcmp(argv[1], "-t") == 0) {
  93                                 if (argc > 2) {
  94                                         timeout = atoi(argv[2]);
  95                                         if (argc > 3) {
  96                                                 device = argv[3];
  97                                         }
  98                                 }
  99                         } else {
 100                                 if (argc > 2) {
 101                                         device = argv[2];
 102                                 }
 103                         }
 104                 } else {
 105                         device = argv[1];
 106                 }
 107                 if (device) {
 108                         close(0);
 109                         close(1);
 110                         close(2);
 111                         if (open(device, O_RDWR) >= 0) {
 112                                 dup(0);
 113                                 dup(0);
 114                         } else {
 115                                 syslog(LOG_WARNING, "cannot open %s\n", device);
 116                                 exit(EXIT_FAILURE);
 117                         }
 118                 }
 119         }
 120         if (access(passwd_file, 0) == -1) {
 121                 syslog(LOG_WARNING, "No password file\n");
 122                 error_msg_and_die("No password file\n");
 123         }
 124         if (!isatty(0) || !isatty(1) || !isatty(2)) {
 125                 exit(EXIT_FAILURE);
 126         }
 127
 128
 129         /* Clear out anything dangerous from the environment */
 130         for (p = forbid; *p; p++)
 131                 unsetenv(*p);
 132
 133
 134         signal(SIGALRM, catchalarm);
 135         alarm(timeout);
 136         if (!(pwd = getpwnam(name))) {
 137                 syslog(LOG_WARNING, "No password entry for `root'\n");
 138                 error_msg_and_die("No password entry for `root'\n");
 139         }
 140         pwent = *pwd;
 141 #ifdef CONFIG_FEATURE_SHADOWPASSWDS
 142         spwd = NULL;
 143         if (pwd && ((strcmp(pwd->pw_passwd, "x") == 0)
 144                                 || (strcmp(pwd->pw_passwd, "*") == 0))) {
 145                 endspent();
 146                 spwd = getspnam(name);
 147                 if (spwd) {
 148                         pwent.pw_passwd = spwd->sp_pwdp;
 149                 }
 150         }
 151 #endif                                                  /* CONFIG_FEATURE_SHADOWPASSWDS */
 152         while (1) {
 153                 cp = getpass(SULOGIN_PROMPT);
 154                 if (!cp || !*cp) {
 155                         puts("\n");
 156                         fflush(stdout);
 157                         syslog(LOG_INFO, "Normal startup\n");
 158                         exit(EXIT_SUCCESS);
 159                 } else {
 160                         safe_strncpy(pass, cp, sizeof(pass));
 161                         bzero(cp, strlen(cp));
 162                 }
 163                 if (strcmp(pw_encrypt(pass, pwent.pw_passwd), pwent.pw_passwd) == 0) {
 164                         break;
 165                 }
 166                 time(&start);
 167                 now = start;
 168                 while (difftime(now, start) < FAIL_DELAY) {
 169                         sleep(FAIL_DELAY);
 170                         time(&now);
 171                 }
 172                 puts("Login incorrect");
 173                 fflush(stdout);
 174                 syslog(LOG_WARNING, "Incorrect root password\n");
 175         }
 176         bzero(pass, strlen(pass));
 177         alarm(0);
 178         signal(SIGALRM, SIG_DFL);
 179         puts("Entering System Maintenance Mode\n");
 180         fflush(stdout);
 181         syslog(LOG_INFO, "System Maintenance Mode\n");
 182         run_shell(pwent.pw_shell, 1, 0, 0);
 183         return (0);
 184 }