1 /*- 2 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #ifndef lint 9 static char copyright[] = 10 "@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\ 11 The Regents of the University of California. All rights reserved.\n"; 12 #endif /* not lint */ 13 14 #ifndef lint 15 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 04/02/94"; 16 #endif /* not lint */ 17 18 /* 19 * login [ name ] 20 * login -h hostname (for telnetd, etc.) 21 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 22 */ 23 24 #include <sys/param.h> 25 #include <sys/stat.h> 26 #include <sys/time.h> 27 #include <sys/resource.h> 28 #include <sys/file.h> 29 30 #include <err.h> 31 #include <errno.h> 32 #include <grp.h> 33 #include <pwd.h> 34 #include <setjmp.h> 35 #include <signal.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <syslog.h> 40 #include <ttyent.h> 41 #include <tzfile.h> 42 #include <unistd.h> 43 #include <utmp.h> 44 45 #include "pathnames.h" 46 47 void badlogin __P((char *)); 48 void checknologin __P((void)); 49 void dolastlog __P((int)); 50 void getloginname __P((void)); 51 void motd __P((void)); 52 int rootterm __P((char *)); 53 void sigint __P((int)); 54 void sleepexit __P((int)); 55 char *stypeof __P((char *)); 56 void timedout __P((int)); 57 #ifdef KERBEROS 58 int klogin __P((struct passwd *, char *, char *, char *)); 59 #endif 60 61 extern void login __P((struct utmp *)); 62 63 #define TTYGRPNAME "tty" /* name of group to own ttys */ 64 65 /* 66 * This bounds the time given to login. Not a define so it can 67 * be patched on machines where it's too small. 68 */ 69 u_int timeout = 300; 70 71 #ifdef KERBEROS 72 int notickets = 1; 73 char *instance; 74 char *krbtkfile_env; 75 int authok; 76 #endif 77 78 struct passwd *pwd; 79 int failures; 80 char term[64], *envinit[1], *hostname, *username, *tty; 81 82 int 83 main(argc, argv) 84 int argc; 85 char *argv[]; 86 { 87 extern char **environ; 88 struct group *gr; 89 struct stat st; 90 struct timeval tp; 91 struct utmp utmp; 92 int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval; 93 uid_t uid; 94 char *domain, *p, *salt, *ttyn; 95 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 96 char localhost[MAXHOSTNAMELEN]; 97 98 (void)signal(SIGALRM, timedout); 99 (void)alarm(timeout); 100 (void)signal(SIGQUIT, SIG_IGN); 101 (void)signal(SIGINT, SIG_IGN); 102 (void)setpriority(PRIO_PROCESS, 0, 0); 103 104 openlog("login", LOG_ODELAY, LOG_AUTH); 105 106 /* 107 * -p is used by getty to tell login not to destroy the environment 108 * -f is used to skip a second login authentication 109 * -h is used by other servers to pass the name of the remote 110 * host to login so that it may be placed in utmp and wtmp 111 */ 112 domain = NULL; 113 if (gethostname(localhost, sizeof(localhost)) < 0) 114 syslog(LOG_ERR, "couldn't get local hostname: %m"); 115 else 116 domain = strchr(localhost, '.'); 117 118 fflag = hflag = pflag = 0; 119 uid = getuid(); 120 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 121 switch (ch) { 122 case 'f': 123 fflag = 1; 124 break; 125 case 'h': 126 if (uid) 127 errx(1, "-h option: %s", strerror(EPERM)); 128 hflag = 1; 129 if (domain && (p = strchr(optarg, '.')) && 130 strcasecmp(p, domain) == 0) 131 *p = 0; 132 hostname = optarg; 133 break; 134 case 'p': 135 pflag = 1; 136 break; 137 case '?': 138 default: 139 if (!uid) 140 syslog(LOG_ERR, "invalid flag %c", ch); 141 (void)fprintf(stderr, 142 "usage: login [-fp] [-h hostname] [username]\n"); 143 exit(1); 144 } 145 argc -= optind; 146 argv += optind; 147 148 if (*argv) { 149 username = *argv; 150 ask = 0; 151 } else 152 ask = 1; 153 154 for (cnt = getdtablesize(); cnt > 2; cnt--) 155 (void)close(cnt); 156 157 ttyn = ttyname(STDIN_FILENO); 158 if (ttyn == NULL || *ttyn == '\0') { 159 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 160 ttyn = tname; 161 } 162 if (tty = strrchr(ttyn, '/')) 163 ++tty; 164 else 165 tty = ttyn; 166 167 for (cnt = 0;; ask = 1) { 168 if (ask) { 169 fflag = 0; 170 getloginname(); 171 } 172 rootlogin = 0; 173 #ifdef KERBEROS 174 if ((instance = strchr(username, '.')) != NULL) { 175 if (strncmp(instance, ".root", 5) == 0) 176 rootlogin = 1; 177 *instance++ = '\0'; 178 } else 179 instance = ""; 180 #endif 181 if (strlen(username) > UT_NAMESIZE) 182 username[UT_NAMESIZE] = '\0'; 183 184 /* 185 * Note if trying multiple user names; log failures for 186 * previous user name, but don't bother logging one failure 187 * for nonexistent name (mistyped username). 188 */ 189 if (failures && strcmp(tbuf, username)) { 190 if (failures > (pwd ? 0 : 1)) 191 badlogin(tbuf); 192 failures = 0; 193 } 194 (void)strcpy(tbuf, username); 195 196 if (pwd = getpwnam(username)) 197 salt = pwd->pw_passwd; 198 else 199 salt = "xx"; 200 201 /* 202 * if we have a valid account name, and it doesn't have a 203 * password, or the -f option was specified and the caller 204 * is root or the caller isn't changing their uid, don't 205 * authenticate. 206 */ 207 if (pwd && (*pwd->pw_passwd == '\0' || 208 fflag && (uid == 0 || uid == pwd->pw_uid))) 209 break; 210 fflag = 0; 211 if (pwd && pwd->pw_uid == 0) 212 rootlogin = 1; 213 214 (void)setpriority(PRIO_PROCESS, 0, -4); 215 216 p = getpass("Password:"); 217 218 if (pwd) { 219 #ifdef KERBEROS 220 rval = klogin(pwd, instance, localhost, p); 221 if (rval != 0 && rootlogin && pwd->pw_uid != 0) 222 rootlogin = 0; 223 if (rval == 0) 224 authok = 1; 225 else if (rval == 1) 226 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 227 #else 228 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 229 #endif 230 } 231 memset(p, 0, strlen(p)); 232 233 (void)setpriority(PRIO_PROCESS, 0, 0); 234 235 /* 236 * If trying to log in as root without Kerberos, 237 * but with insecure terminal, refuse the login attempt. 238 */ 239 #ifdef KERBEROS 240 if (authok == 0) 241 #endif 242 if (pwd && rootlogin && !rootterm(tty)) { 243 (void)fprintf(stderr, 244 "%s login refused on this terminal.\n", 245 pwd->pw_name); 246 if (hostname) 247 syslog(LOG_NOTICE, 248 "LOGIN %s REFUSED FROM %s ON TTY %s", 249 pwd->pw_name, hostname, tty); 250 else 251 syslog(LOG_NOTICE, 252 "LOGIN %s REFUSED ON TTY %s", 253 pwd->pw_name, tty); 254 continue; 255 } 256 257 if (pwd && !rval) 258 break; 259 260 (void)printf("Login incorrect\n"); 261 failures++; 262 /* we allow 10 tries, but after 3 we start backing off */ 263 if (++cnt > 3) { 264 if (cnt >= 10) { 265 badlogin(username); 266 sleepexit(1); 267 } 268 sleep((u_int)((cnt - 3) * 5)); 269 } 270 } 271 272 /* committed to login -- turn off timeout */ 273 (void)alarm((u_int)0); 274 275 endpwent(); 276 277 /* if user not super-user, check for disabled logins */ 278 if (!rootlogin) 279 checknologin(); 280 281 if (chdir(pwd->pw_dir) < 0) { 282 (void)printf("No home directory %s!\n", pwd->pw_dir); 283 if (chdir("/")) 284 exit(0); 285 pwd->pw_dir = "/"; 286 (void)printf("Logging in with home = \"/\".\n"); 287 } 288 289 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 290 291 if (pwd->pw_change || pwd->pw_expire) 292 (void)gettimeofday(&tp, (struct timezone *)NULL); 293 if (pwd->pw_change) 294 if (tp.tv_sec >= pwd->pw_change) { 295 (void)printf("Sorry -- your password has expired.\n"); 296 sleepexit(1); 297 } else if (pwd->pw_change - tp.tv_sec < 298 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 299 (void)printf("Warning: your password expires on %s", 300 ctime(&pwd->pw_change)); 301 if (pwd->pw_expire) 302 if (tp.tv_sec >= pwd->pw_expire) { 303 (void)printf("Sorry -- your account has expired.\n"); 304 sleepexit(1); 305 } else if (pwd->pw_expire - tp.tv_sec < 306 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 307 (void)printf("Warning: your account expires on %s", 308 ctime(&pwd->pw_expire)); 309 310 /* Nothing else left to fail -- really log in. */ 311 memset((void *)&utmp, 0, sizeof(utmp)); 312 (void)time(&utmp.ut_time); 313 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 314 if (hostname) 315 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 316 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 317 login(&utmp); 318 319 dolastlog(quietlog); 320 321 (void)chown(ttyn, pwd->pw_uid, 322 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 323 (void)setgid(pwd->pw_gid); 324 325 initgroups(username, pwd->pw_gid); 326 327 if (*pwd->pw_shell == '\0') 328 pwd->pw_shell = _PATH_BSHELL; 329 330 /* Destroy environment unless user has requested its preservation. */ 331 if (!pflag) 332 environ = envinit; 333 (void)setenv("HOME", pwd->pw_dir, 1); 334 (void)setenv("SHELL", pwd->pw_shell, 1); 335 if (term[0] == '\0') 336 (void)strncpy(term, stypeof(tty), sizeof(term)); 337 (void)setenv("TERM", term, 0); 338 (void)setenv("LOGNAME", pwd->pw_name, 1); 339 (void)setenv("USER", pwd->pw_name, 1); 340 (void)setenv("PATH", _PATH_DEFPATH, 0); 341 #ifdef KERBEROS 342 if (krbtkfile_env) 343 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 344 #endif 345 346 if (tty[sizeof("tty")-1] == 'd') 347 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 348 349 /* If fflag is on, assume caller/authenticator has logged root login. */ 350 if (rootlogin && fflag == 0) 351 if (hostname) 352 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 353 username, tty, hostname); 354 else 355 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 356 357 #ifdef KERBEROS 358 if (!quietlog && notickets == 1) 359 (void)printf("Warning: no Kerberos tickets issued.\n"); 360 #endif 361 362 if (!quietlog) { 363 (void)printf("%s\n\t%s %s\n\n", 364 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", 365 "The Regents of the University of California. ", 366 "All rights reserved."); 367 motd(); 368 (void)snprintf(tbuf, 369 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 370 if (stat(tbuf, &st) == 0 && st.st_size != 0) 371 (void)printf("You have %smail.\n", 372 (st.st_mtime > st.st_atime) ? "new " : ""); 373 } 374 375 (void)signal(SIGALRM, SIG_DFL); 376 (void)signal(SIGQUIT, SIG_DFL); 377 (void)signal(SIGINT, SIG_DFL); 378 (void)signal(SIGTSTP, SIG_IGN); 379 380 tbuf[0] = '-'; 381 (void)strcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? 382 p + 1 : pwd->pw_shell); 383 384 if (setlogin(pwd->pw_name) < 0) 385 syslog(LOG_ERR, "setlogin() failure: %m"); 386 387 /* Discard permissions last so can't get killed and drop core. */ 388 if (rootlogin) 389 (void) setuid(0); 390 else 391 (void) setuid(pwd->pw_uid); 392 393 execlp(pwd->pw_shell, tbuf, 0); 394 err(1, "%s", pwd->pw_shell); 395 } 396 397 #ifdef KERBEROS 398 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 399 #else 400 #define NBUFSIZ (UT_NAMESIZE + 1) 401 #endif 402 403 void 404 getloginname() 405 { 406 int ch; 407 char *p; 408 static char nbuf[NBUFSIZ]; 409 410 for (;;) { 411 (void)printf("login: "); 412 for (p = nbuf; (ch = getchar()) != '\n'; ) { 413 if (ch == EOF) { 414 badlogin(username); 415 exit(0); 416 } 417 if (p < nbuf + (NBUFSIZ - 1)) 418 *p++ = ch; 419 } 420 if (p > nbuf) 421 if (nbuf[0] == '-') 422 (void)fprintf(stderr, 423 "login names may not start with '-'.\n"); 424 else { 425 *p = '\0'; 426 username = nbuf; 427 break; 428 } 429 } 430 } 431 432 int 433 rootterm(ttyn) 434 char *ttyn; 435 { 436 struct ttyent *t; 437 438 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 439 } 440 441 jmp_buf motdinterrupt; 442 443 void 444 motd() 445 { 446 int fd, nchars; 447 sig_t oldint; 448 char tbuf[8192]; 449 450 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 451 return; 452 oldint = signal(SIGINT, sigint); 453 if (setjmp(motdinterrupt) == 0) 454 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 455 (void)write(fileno(stdout), tbuf, nchars); 456 (void)signal(SIGINT, oldint); 457 (void)close(fd); 458 } 459 460 /* ARGSUSED */ 461 void 462 sigint(signo) 463 int signo; 464 { 465 466 longjmp(motdinterrupt, 1); 467 } 468 469 /* ARGSUSED */ 470 void 471 timedout(signo) 472 int signo; 473 { 474 475 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 476 exit(0); 477 } 478 479 void 480 checknologin() 481 { 482 int fd, nchars; 483 char tbuf[8192]; 484 485 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 486 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 487 (void)write(fileno(stdout), tbuf, nchars); 488 sleepexit(0); 489 } 490 } 491 492 void 493 dolastlog(quiet) 494 int quiet; 495 { 496 struct lastlog ll; 497 int fd; 498 499 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 500 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 501 if (!quiet) { 502 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 503 ll.ll_time != 0) { 504 (void)printf("Last login: %.*s ", 505 24-5, (char *)ctime(&ll.ll_time)); 506 if (*ll.ll_host != '\0') 507 (void)printf("from %.*s\n", 508 (int)sizeof(ll.ll_host), 509 ll.ll_host); 510 else 511 (void)printf("on %.*s\n", 512 (int)sizeof(ll.ll_line), 513 ll.ll_line); 514 } 515 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 516 } 517 memset((void *)&ll, 0, sizeof(ll)); 518 (void)time(&ll.ll_time); 519 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 520 if (hostname) 521 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 522 (void)write(fd, (char *)&ll, sizeof(ll)); 523 (void)close(fd); 524 } 525 } 526 527 void 528 badlogin(name) 529 char *name; 530 { 531 532 if (failures == 0) 533 return; 534 if (hostname) { 535 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 536 failures, failures > 1 ? "S" : "", hostname); 537 syslog(LOG_AUTHPRIV|LOG_NOTICE, 538 "%d LOGIN FAILURE%s FROM %s, %s", 539 failures, failures > 1 ? "S" : "", hostname, name); 540 } else { 541 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 542 failures, failures > 1 ? "S" : "", tty); 543 syslog(LOG_AUTHPRIV|LOG_NOTICE, 544 "%d LOGIN FAILURE%s ON %s, %s", 545 failures, failures > 1 ? "S" : "", tty, name); 546 } 547 } 548 549 #undef UNKNOWN 550 #define UNKNOWN "su" 551 552 char * 553 stypeof(ttyid) 554 char *ttyid; 555 { 556 struct ttyent *t; 557 558 return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 559 } 560 561 void 562 sleepexit(eval) 563 int eval; 564 { 565 566 (void)sleep(5); 567 exit(eval); 568 } 569