2.11BSD#431 - /usr/src/bin/login/login.c

   1: /*
   2:  * Copyright (c) 1980, 1987, 1988 The Regents of the University of California.
   3:  * All rights reserved.
   4:  *
   5:  * Redistribution and use in source and binary forms are permitted
   6:  * provided that the above copyright notice and this paragraph are
   7:  * duplicated in all such forms and that any documentation,
   8:  * advertising materials, and other materials related to such
   9:  * distribution and use acknowledge that the software was developed
  10:  * by the University of California, Berkeley.  The name of the
  11:  * University may not be used to endorse or promote products derived
  12:  * from this software without specific prior written permission.
  13:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15:  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16:  */
  17: 
  18: #if defined(DOSCCS) && !defined(lint)
  19: char copyright[] =
  20: "@(#) Copyright (c) 1980, 1987, 1988 The Regents of the University of California.\n\
  21:  All rights reserved.\n";
  22: 
  23: static char sccsid[] = "@(#)login.c	5.40.2 (2.11BSD GTE) 1997/9/26";
  24: #endif
  25: 
  26: /*
  27:  * login [ name ]
  28:  * login -h hostname	(for telnetd, etc.)
  29:  * login -f name	(for pre-authenticated login: datakit, xterm, etc.)
  30:  */
  31: 
  32: #include <sys/param.h>
  33: #include <sys/quota.h>
  34: #include <sys/stat.h>
  35: #include <sys/time.h>
  36: #include <sys/resource.h>
  37: #include <sys/file.h>
  38: #include <sgtty.h>
  39: 
  40: #include <utmp.h>
  41: #include <signal.h>
  42: #include <errno.h>
  43: #include <ttyent.h>
  44: #include <syslog.h>
  45: #include <grp.h>
  46: #include <pwd.h>
  47: #include <setjmp.h>
  48: #include <stdio.h>
  49: #include <strings.h>
  50: #include <netdb.h>
  51: #include <tzfile.h>
  52: #include <lastlog.h>
  53: #include "pathnames.h"
  54: 
  55: #ifdef  KERBEROS
  56: #include <kerberos/krb.h>
  57: #include <sys/termios.h>
  58: char    realm[REALM_SZ];
  59: int kerror = KSUCCESS, notickets = 1;
  60: #endif
  61: 
  62: #define TTYGRPNAME  "tty"       /* name of group to own ttys */
  63: 
  64: /*
  65:  * This bounds the time given to login.  Not a define so it can
  66:  * be patched on machines where it's too small.
  67:  */
  68: int timeout = 300;
  69: 
  70: struct  passwd *pwd;
  71: int failures;
  72: char    term[64], *hostname, *username, *tty;
  73: 
  74: struct  sgttyb sgttyb;
  75: struct  tchars tc = {
  76:     CINTR, CQUIT, CSTART, CSTOP, CEOT, CBRK
  77: };
  78: struct  ltchars ltc = {
  79:     CSUSP, CDSUSP, CRPRNT, CFLUSH, CWERASE, CLNEXT
  80: };
  81: 
  82: char *months[] =
  83:     { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug",
  84:       "Sep", "Oct", "Nov", "Dec" };
  85: 
  86: main(argc, argv)
  87:     int argc;
  88:     char **argv;
  89: {
  90:     extern int errno, optind;
  91:     extern char *optarg, **environ;
  92:     struct timeval tp;
  93:     struct tm *ttp;
  94:     struct group *gr;
  95:     register int ch;
  96:     register char *p;
  97:     int ask, fflag, hflag, pflag, cnt;
  98:     int quietlog, passwd_req, ioctlval, timedout();
  99:     char *domain, *salt, *envinit[1], *ttyn, *pp;
 100:     char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10];
 101:     char *ctime(), *ttyname(), *stypeof(), *crypt(), *getpass();
 102:     time_t time();
 103:     off_t lseek();
 104: 
 105:     (void)signal(SIGALRM, timedout);
 106:     (void)alarm((u_int)timeout);
 107:     (void)signal(SIGQUIT, SIG_IGN);
 108:     (void)signal(SIGINT, SIG_IGN);
 109:     (void)setpriority(PRIO_PROCESS, 0, 0);
 110:     (void)quota(Q_SETUID, 0, 0, 0);
 111: 
 112:     /*
 113: 	 * -p is used by getty to tell login not to destroy the environment
 114:  	 * -f is used to skip a second login authentication
 115: 	 * -h is used by other servers to pass the name of the remote
 116: 	 *    host to login so that it may be placed in utmp and wtmp
 117: 	 */
 118:     (void)gethostname(tbuf, sizeof(tbuf));
 119:     domain = index(tbuf, '.');
 120: 
 121:     fflag = hflag = pflag = 0;
 122:     passwd_req = 1;
 123:     while ((ch = getopt(argc, argv, "fh:p")) != EOF)
 124:         switch (ch) {
 125:         case 'f':
 126:             fflag = 1;
 127:             break;
 128:         case 'h':
 129:             if (getuid()) {
 130:                 (void)fprintf(stderr,
 131:                     "login: -h for super-user only.\n");
 132:                 exit(1);
 133:             }
 134:             hflag = 1;
 135:             if (domain && (p = index(optarg, '.')) &&
 136:                 strcasecmp(p, domain) == 0)
 137:                 *p = 0;
 138:             hostname = optarg;
 139:             break;
 140:         case 'p':
 141:             pflag = 1;
 142:             break;
 143:         case '?':
 144:         default:
 145:             (void)fprintf(stderr,
 146:                 "usage: login [-fp] [username]\n");
 147:             exit(1);
 148:         }
 149:     argc -= optind;
 150:     argv += optind;
 151:     if (*argv) {
 152:         username = *argv;
 153:         ask = 0;
 154:     } else
 155:         ask = 1;
 156: 
 157:     ioctlval = 0;
 158:     (void)ioctl(0, TIOCLSET, &ioctlval);
 159:     (void)ioctl(0, TIOCNXCL, 0);
 160:     (void)fcntl(0, F_SETFL, ioctlval);
 161:     (void)ioctl(0, TIOCGETP, &sgttyb);
 162:     sgttyb.sg_erase = CERASE;
 163:     sgttyb.sg_kill = CKILL;
 164:     (void)ioctl(0, TIOCSLTC, &ltc);
 165:     (void)ioctl(0, TIOCSETC, &tc);
 166:     (void)ioctl(0, TIOCSETP, &sgttyb);
 167: 
 168:     for (cnt = getdtablesize(); cnt > 2; cnt--)
 169:         close(cnt);
 170: 
 171:     ttyn = ttyname(0);
 172:     if (ttyn == NULL || *ttyn == '\0') {
 173:         (void)sprintf(tname, "%s??", _PATH_TTY);
 174:         ttyn = tname;
 175:     }
 176:     if (tty = rindex(ttyn, '/'))
 177:         ++tty;
 178:     else
 179:         tty = ttyn;
 180: 
 181:     openlog("login", LOG_ODELAY, LOG_AUTH);
 182: 
 183:     for (cnt = 0;; ask = 1) {
 184:         ioctlval = 0;
 185:         (void)ioctl(0, TIOCSETD, &ioctlval);
 186: 
 187:         if (ask) {
 188:             fflag = 0;
 189:             getloginname();
 190:         }
 191:         /*
 192: 		 * Note if trying multiple user names;
 193: 		 * log failures for previous user name,
 194: 		 * but don't bother logging one failure
 195: 		 * for nonexistent name (mistyped username).
 196: 		 */
 197:         if (failures && strcmp(tbuf, username)) {
 198:             if (failures > (pwd ? 0 : 1))
 199:                 badlogin(tbuf);
 200:             failures = 0;
 201:         }
 202:         (void)strcpy(tbuf, username);
 203:         if (pwd = getpwnam(username))
 204:             salt = pwd->pw_passwd;
 205:         else
 206:             salt = "xx";
 207: 
 208:         /* if user not super-user, check for disabled logins */
 209:         if (pwd == NULL || pwd->pw_uid)
 210:             checknologin();
 211: 
 212:         /*
 213: 		 * Disallow automatic login to root; if not invoked by
 214: 		 * root, disallow if the uid's differ.
 215: 		 */
 216:         if (fflag && pwd) {
 217:             int uid = getuid();
 218: 
 219:             passwd_req = pwd->pw_uid == 0 ||
 220:                 (uid && uid != pwd->pw_uid);
 221:         }
 222: 
 223:         /*
 224: 		 * If trying to log in as root, but with insecure terminal,
 225: 		 * refuse the login attempt.
 226: 		 */
 227:         if (pwd->pw_uid == 0 && !rootterm(tty)) {
 228:             (void)fprintf(stderr,
 229:                 "%s login refused on this terminal.\n",
 230:                 pwd->pw_name);
 231:             if (hostname)
 232:                 syslog(LOG_NOTICE,
 233:                     "LOGIN %s REFUSED FROM %s ON TTY %s",
 234:                     pwd->pw_name, hostname, tty);
 235:             else
 236:                 syslog(LOG_NOTICE,
 237:                     "LOGIN %s REFUSED ON TTY %s",
 238:                      pwd->pw_name, tty);
 239:             continue;
 240:         }
 241: 
 242:         /*
 243: 		 * If no pre-authentication and a password exists
 244: 		 * for this user, prompt for one and verify it.
 245: 		 */
 246:         if (!passwd_req || (pwd && !*pwd->pw_passwd))
 247:             break;
 248: 
 249:         setpriority(PRIO_PROCESS, 0, -4);
 250:         pp = getpass("Password:");
 251:         p = crypt(pp, salt);
 252:         setpriority(PRIO_PROCESS, 0, 0);
 253: 
 254: #ifdef  KERBEROS
 255: 
 256:         /*
 257: 		 * If not present in pw file, act as we normally would.
 258: 		 * If we aren't Kerberos-authenticated, try the normal
 259: 		 * pw file for a password.  If that's ok, log the user
 260: 		 * in without issueing any tickets.
 261: 		 */
 262: 
 263:         if (pwd && !krb_get_lrealm(realm,1)) {
 264:             /*
 265: 			 * get TGT for local realm; be careful about uid's
 266: 			 * here for ticket file ownership
 267: 			 */
 268:             (void)setreuid(geteuid(),pwd->pw_uid);
 269:             kerror = krb_get_pw_in_tkt(pwd->pw_name, "", realm,
 270:                 "krbtgt", realm, DEFAULT_TKT_LIFE, pp);
 271:             (void)setuid(0);
 272:             if (kerror == INTK_OK) {
 273:                 bzero(pp, strlen(pp));
 274:                 notickets = 0;  /* user got ticket */
 275:                 break;
 276:             }
 277:         }
 278: #endif
 279:         (void) bzero(pp, strlen(pp));
 280:         if (pwd && !strcmp(p, pwd->pw_passwd))
 281:             break;
 282: 
 283:         (void)printf("Login incorrect\n");
 284:         failures++;
 285:         /* we allow 10 tries, but after 3 we start backing off */
 286:         if (++cnt > 3) {
 287:             if (cnt >= 10) {
 288:                 badlogin(username);
 289:                 (void)ioctl(0, TIOCHPCL, (struct sgttyb *)NULL);
 290:                 sleepexit(1);
 291:             }
 292:             sleep((u_int)((cnt - 3) * 5));
 293:         }
 294:     }
 295: 
 296:     /* committed to login -- turn off timeout */
 297:     (void)alarm((u_int)0);
 298: 
 299:     /* paranoia... */
 300:     endpwent();
 301: 
 302:     if (quota(Q_SETUID, pwd->pw_uid, 0, 0) < 0 && errno != EINVAL) {
 303:         switch(errno) {
 304:         case EUSERS:
 305:             (void)fprintf(stderr,
 306:         "Too many users logged on already.\nTry again later.\n");
 307:             break;
 308:         case EPROCLIM:
 309:             (void)fprintf(stderr,
 310:                 "You have too many processes running.\n");
 311:             break;
 312:         default:
 313:             perror("quota (Q_SETUID)");
 314:         }
 315:         sleepexit(0);
 316:     }
 317: 
 318:     if (chdir(pwd->pw_dir) < 0) {
 319:         (void)printf("No directory %s!\n", pwd->pw_dir);
 320:         if (chdir("/"))
 321:             exit(0);
 322:         pwd->pw_dir = "/";
 323:         (void)printf("Logging in with home = \"/\".\n");
 324:     }
 325: 
 326:     quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
 327: 
 328: #ifdef KERBEROS
 329:     if (notickets && !quietlog)
 330:         (void)printf("Warning: no Kerberos tickets issued\n");
 331: #endif
 332: 
 333: #define TWOWEEKS    (14*24*60*60)
 334:     if (pwd->pw_change || pwd->pw_expire)
 335:         (void)gettimeofday(&tp, (struct timezone *)NULL);
 336:     if (pwd->pw_change)
 337:         if (tp.tv_sec >= pwd->pw_change) {
 338:             (void)printf("Sorry -- your password has expired.\n");
 339:             sleepexit(1);
 340:         }
 341:         else if (pwd->pw_change - tp.tv_sec < TWOWEEKS && !quietlog) {
 342:             ttp = localtime(&pwd->pw_change);
 343:             (void)printf("Warning: your password expires on %s %d, %d\n",
 344:                 months[ttp->tm_mon], ttp->tm_mday, TM_YEAR_BASE + ttp->tm_year);
 345:         }
 346:     if (pwd->pw_expire)
 347:         if (tp.tv_sec >= pwd->pw_expire) {
 348:             (void)printf("Sorry -- your account has expired.\n");
 349:             sleepexit(1);
 350:         }
 351:         else if (pwd->pw_expire - tp.tv_sec < TWOWEEKS && !quietlog) {
 352:             ttp = localtime(&pwd->pw_expire);
 353:             (void)printf("Warning: your account expires on %s %d, %d\n",
 354:                 months[ttp->tm_mon], ttp->tm_mday, TM_YEAR_BASE + ttp->tm_year);
 355:         }
 356: 
 357:     /* nothing else left to fail -- really log in */
 358:     {
 359:         struct utmp utmp;
 360: 
 361:         bzero((char *)&utmp, sizeof(utmp));
 362:         (void)time(&utmp.ut_time);
 363:         strncpy(utmp.ut_name, username, sizeof(utmp.ut_name));
 364:         if (hostname)
 365:             strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
 366:         strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
 367:         login(&utmp);
 368:     }
 369: 
 370:     dolastlog(quietlog);
 371: 
 372:     if (!hflag) {                   /* XXX */
 373:         static struct winsize win = { 0, 0, 0, 0 };
 374: 
 375:         (void)ioctl(0, TIOCSWINSZ, &win);
 376:     }
 377: 
 378:     (void)chown(ttyn, pwd->pw_uid,
 379:         (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid);
 380:     (void)chmod(ttyn, 0620);
 381:     (void)setgid(pwd->pw_gid);
 382: 
 383:     initgroups(username, pwd->pw_gid);
 384: 
 385:     quota(Q_DOWARN, pwd->pw_uid, (dev_t)-1, 0);
 386: 
 387:     if (*pwd->pw_shell == '\0')
 388:         pwd->pw_shell = _PATH_BSHELL;
 389:     /* turn on new line discipline for the csh */
 390:     else if (!strcmp(pwd->pw_shell, _PATH_CSHELL)) {
 391:         ioctlval = NTTYDISC;
 392:         (void)ioctl(0, TIOCSETD, &ioctlval);
 393:     }
 394: 
 395:     /* destroy environment unless user has requested preservation */
 396:     if (!pflag)
 397:         environ = envinit;
 398:     (void)setenv("HOME", pwd->pw_dir, 1);
 399:     (void)setenv("SHELL", pwd->pw_shell, 1);
 400:     if (term[0] == '\0')
 401:         strncpy(term, stypeof(tty), sizeof(term));
 402:     (void)setenv("TERM", term, 0);
 403:     (void)setenv("USER", pwd->pw_name, 1);
 404:     (void)setenv("PATH", _PATH_DEFPATH, 0);
 405: 
 406:     if (tty[sizeof("tty")-1] == 'd')
 407:         syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
 408:     if (pwd->pw_uid == 0)
 409:         if (hostname)
 410:             syslog(LOG_NOTICE, "ROOT LOGIN ON %s FROM %s",
 411:                 tty, hostname);
 412:         else
 413:             syslog(LOG_NOTICE, "ROOT LOGIN ON %s", tty);
 414: 
 415:     if (!quietlog) {
 416:         struct stat st;
 417: 
 418:         motd();
 419:         (void)sprintf(tbuf, "%s/%s", _PATH_MAILDIR, pwd->pw_name);
 420:         if (stat(tbuf, &st) == 0 && st.st_size != 0)
 421:             (void)printf("You have %smail.\n",
 422:                 (st.st_mtime > st.st_atime) ? "new " : "");
 423:     }
 424: 
 425:     (void)signal(SIGALRM, SIG_DFL);
 426:     (void)signal(SIGQUIT, SIG_DFL);
 427:     (void)signal(SIGINT, SIG_DFL);
 428:     (void)signal(SIGTSTP, SIG_IGN);
 429: 
 430:     tbuf[0] = '-';
 431:     strcpy(tbuf + 1, (p = rindex(pwd->pw_shell, '/')) ?
 432:         p + 1 : pwd->pw_shell);
 433: 
 434:     if  (setlogin(pwd->pw_name) < 0)
 435:         fprintf(stderr, "login: setlogin(): %s\n", strerror(errno));
 436: 
 437:     /* discard permissions last so can't get killed and drop core */
 438:     (void)setuid(pwd->pw_uid);
 439: 
 440:     execlp(pwd->pw_shell, tbuf, 0);
 441:     (void)fprintf(stderr, "login: no shell: %s\n", strerror(errno));
 442:     exit(0);
 443: }
 444: 
 445: getloginname()
 446: {
 447:     register int ch;
 448:     register char *p;
 449:     static char nbuf[UT_NAMESIZE + 1];
 450: 
 451:     for (;;) {
 452:         (void)printf("login: ");
 453:         for (p = nbuf; (ch = getchar()) != '\n'; ) {
 454:             if (ch == EOF) {
 455:                 badlogin(username);
 456:                 exit(0);
 457:             }
 458:             if (p < nbuf + UT_NAMESIZE)
 459:                 *p++ = ch;
 460:         }
 461:         if (p > nbuf)
 462:             if (nbuf[0] == '-')
 463:                 (void)fprintf(stderr,
 464:                     "login names may not start with '-'.\n");
 465:             else {
 466:                 *p = '\0';
 467:                 username = nbuf;
 468:                 break;
 469:             }
 470:     }
 471: }
 472: 
 473: timedout()
 474: {
 475:     (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout);
 476:     exit(0);
 477: }
 478: 
 479: rootterm(ttyn)
 480:     char *ttyn;
 481: {
 482:     struct ttyent *t;
 483: 
 484:     return((t = getttynam(ttyn)) && t->ty_status&TTY_SECURE);
 485: }
 486: 
 487: jmp_buf motdinterrupt;
 488: 
 489: motd()
 490: {
 491:     register int fd, nchars;
 492:     int (*oldint)(), sigint();
 493:     char tbuf[BUFSIZ];
 494: 
 495:     if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0)
 496:         return;
 497:     oldint = signal(SIGINT, sigint);
 498:     if (setjmp(motdinterrupt) == 0)
 499:         while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0)
 500:             (void)write(fileno(stdout), tbuf, nchars);
 501:     (void)signal(SIGINT, oldint);
 502:     (void)close(fd);
 503: }
 504: 
 505: sigint()
 506: {
 507:     longjmp(motdinterrupt, 1);
 508: }
 509: 
 510: checknologin()
 511: {
 512:     register int fd, nchars;
 513:     char tbuf[BUFSIZ];
 514: 
 515:     if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) {
 516:         while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0)
 517:             (void)write(fileno(stdout), tbuf, nchars);
 518:         sleepexit(0);
 519:     }
 520: }
 521: 
 522: dolastlog(quiet)
 523:     int quiet;
 524: {
 525:     struct lastlog ll;
 526:     int fd;
 527:     char *ctime();
 528: 
 529:     if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
 530:         (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
 531:         if (!quiet) {
 532:             if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) &&
 533:                 ll.ll_time != 0) {
 534:                 (void)printf("Last login: %.*s ",
 535:                     24-5, (char *)ctime(&ll.ll_time));
 536:                 if (*ll.ll_host != '\0')
 537:                     (void)printf("from %.*s\n",
 538:                         sizeof(ll.ll_host), ll.ll_host);
 539:                 else
 540:                     (void)printf("on %.*s\n",
 541:                         sizeof(ll.ll_line), ll.ll_line);
 542:             }
 543:             (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
 544:         }
 545:         bzero((char *)&ll, sizeof(ll));
 546:         (void)time(&ll.ll_time);
 547:         strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
 548:         if (hostname)
 549:             strncpy(ll.ll_host, hostname, sizeof(ll.ll_host));
 550:         (void)write(fd, (char *)&ll, sizeof(ll));
 551:         (void)close(fd);
 552:     }
 553: }
 554: 
 555: badlogin(name)
 556:     char *name;
 557: {
 558:     if (failures == 0)
 559:         return;
 560:     if (hostname)
 561:         syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s, %s",
 562:             failures, failures > 1 ? "S" : "", hostname, name);
 563:     else
 564:         syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s, %s",
 565:             failures, failures > 1 ? "S" : "", tty, name);
 566: }
 567: 
 568: #undef  UNKNOWN
 569: #define UNKNOWN "su"
 570: 
 571: char *
 572: stypeof(ttyid)
 573:     char *ttyid;
 574: {
 575:     struct ttyent *t;
 576: 
 577:     return(ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN);
 578: }
 579: 
 580: getstr(buf, cnt, err)
 581:     char *buf, *err;
 582:     int cnt;
 583: {
 584:     char ch;
 585: 
 586:     do {
 587:         if (read(0, &ch, sizeof(ch)) != sizeof(ch))
 588:             exit(1);
 589:         if (--cnt < 0) {
 590:             (void)fprintf(stderr, "%s too long\r\n", err);
 591:             sleepexit(1);
 592:         }
 593:         *buf++ = ch;
 594:     } while (ch);
 595: }
 596: 
 597: sleepexit(eval)
 598:     int eval;
 599: {
 600:     sleep((u_int)5);
 601:     exit(eval);
 602: }

Defined functions

Defined variables

Defined macros