login.c revision 1.10
1 /*- 2 * Copyright (c) 1980, 1987, 1988, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #ifndef lint 35 static char copyright[] = 36 "@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 static char sccsid[] = "@(#)login.c 8.1 (Berkeley) 6/9/93"; 42 #endif /* not lint */ 43 44 /* 45 * login [ name ] 46 * login -h hostname (for telnetd, etc.) 47 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 48 */ 49 50 #include <sys/param.h> 51 #include <sys/stat.h> 52 #include <sys/time.h> 53 #include <sys/resource.h> 54 #include <sys/file.h> 55 56 #include <signal.h> 57 #include <ttyent.h> 58 #include <syslog.h> 59 #include <setjmp.h> 60 #include <tzfile.h> 61 #include <utmp.h> 62 #include <errno.h> 63 #include <grp.h> 64 #include <pwd.h> 65 #include <unistd.h> 66 #include <stdio.h> 67 #include <stdlib.h> 68 #include <string.h> 69 #include "pathnames.h" 70 71 void badlogin __P((char *)); 72 void checknologin __P((void)); 73 void dolastlog __P((int)); 74 void getloginname __P((void)); 75 void motd __P((void)); 76 int rootterm __P((char *)); 77 void sigint __P((int)); 78 void sleepexit __P((int)); 79 char *stypeof __P((char *)); 80 void timedout __P((int)); 81 int pwcheck __P((char *, char *, char *, char *)); 82 #if defined(KERBEROS) || defined(KERBEROS5) 83 int klogin __P((struct passwd *, char *, char *, char *)); 84 void kdestroy __P((void)); 85 void dofork __P((void)); 86 #endif 87 88 #define TTYGRPNAME "tty" /* name of group to own ttys */ 89 90 /* 91 * This bounds the time given to login. Not a define so it can 92 * be patched on machines where it's too small. 93 */ 94 int timeout = 300; 95 96 #if defined(KERBEROS) || defined(KERBEROS5) 97 int notickets = 1; 98 char *instance; 99 char *krbtkfile_env = NULL; 100 int authok; 101 #endif 102 103 struct passwd *pwd; 104 int failures; 105 char term[64], *envinit[1], *hostname, *username, *tty; 106 107 int 108 main(argc, argv) 109 int argc; 110 char *argv[]; 111 { 112 extern char **environ; 113 register int ch; 114 register char *p; 115 struct group *gr; 116 struct stat st; 117 struct timeval tp; 118 struct utmp utmp; 119 int ask, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval, uid; 120 char *domain, *salt, *ttyn; 121 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 122 char localhost[MAXHOSTNAMELEN]; 123 124 (void)signal(SIGALRM, timedout); 125 (void)alarm((u_int)timeout); 126 (void)signal(SIGQUIT, SIG_IGN); 127 (void)signal(SIGINT, SIG_IGN); 128 (void)setpriority(PRIO_PROCESS, 0, 0); 129 130 openlog("login", LOG_ODELAY, LOG_AUTH); 131 132 /* 133 * -p is used by getty to tell login not to destroy the environment 134 * -f is used to skip a second login authentication 135 * -h is used by other servers to pass the name of the remote 136 * host to login so that it may be placed in utmp and wtmp 137 */ 138 domain = NULL; 139 if (gethostname(localhost, sizeof(localhost)) < 0) 140 syslog(LOG_ERR, "couldn't get local hostname: %m"); 141 else 142 domain = index(localhost, '.'); 143 144 fflag = hflag = pflag = 0; 145 uid = getuid(); 146 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 147 switch (ch) { 148 case 'f': 149 fflag = 1; 150 break; 151 case 'h': 152 if (uid) { 153 (void)fprintf(stderr, 154 "login: -h option: %s\n", strerror(EPERM)); 155 exit(1); 156 } 157 hflag = 1; 158 if (domain && (p = index(optarg, '.')) && 159 strcasecmp(p, domain) == 0) 160 *p = 0; 161 hostname = optarg; 162 break; 163 case 'p': 164 pflag = 1; 165 break; 166 case '?': 167 default: 168 if (!uid) 169 syslog(LOG_ERR, "invalid flag %c", ch); 170 (void)fprintf(stderr, 171 "usage: login [-fp] [-h hostname] [username]\n"); 172 exit(1); 173 } 174 argc -= optind; 175 argv += optind; 176 177 if (*argv) { 178 username = *argv; 179 ask = 0; 180 } else 181 ask = 1; 182 183 for (cnt = getdtablesize(); cnt > 2; cnt--) 184 (void)close(cnt); 185 186 ttyn = ttyname(STDIN_FILENO); 187 if (ttyn == NULL || *ttyn == '\0') { 188 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 189 ttyn = tname; 190 } 191 if (tty = rindex(ttyn, '/')) 192 ++tty; 193 else 194 tty = ttyn; 195 196 for (cnt = 0;; ask = 1) { 197 #if defined(KERBEROS) || defined(KERBEROS5) 198 kdestroy(); 199 #endif 200 if (ask) { 201 fflag = 0; 202 getloginname(); 203 } 204 rootlogin = 0; 205 #ifdef KERBEROS 206 if ((instance = index(username, '.')) != NULL) { 207 if (strncmp(instance, ".root", 5) == 0) 208 rootlogin = 1; 209 *instance++ = '\0'; 210 } else 211 instance = ""; 212 #endif 213 #ifdef KERBEROS5 214 if ((instance = index(username, '/')) != NULL) { 215 if (strncmp(instance, "/root", 5) == 0) 216 rootlogin = 1; 217 *instance++ = '\0'; 218 } else 219 instance = ""; 220 #endif 221 if (strlen(username) > UT_NAMESIZE) 222 username[UT_NAMESIZE] = '\0'; 223 224 /* 225 * Note if trying multiple user names; log failures for 226 * previous user name, but don't bother logging one failure 227 * for nonexistent name (mistyped username). 228 */ 229 if (failures && strcmp(tbuf, username)) { 230 if (failures > (pwd ? 0 : 1)) 231 badlogin(tbuf); 232 failures = 0; 233 } 234 (void)strcpy(tbuf, username); 235 236 if (pwd = getpwnam(username)) 237 salt = pwd->pw_passwd; 238 else 239 salt = "xx"; 240 241 /* 242 * if we have a valid account name, and it doesn't have a 243 * password, or the -f option was specified and the caller 244 * is root or the caller isn't changing their uid, don't 245 * authenticate. 246 */ 247 if (pwd) { 248 if (pwd->pw_uid == 0) 249 rootlogin = 1; 250 251 if (fflag && (uid == 0 || uid == pwd->pw_uid)) { 252 /* already authenticated */ 253 break; 254 } else if (pwd->pw_passwd[0] == '\0') { 255 /* pretend password okay */ 256 rval = 0; 257 goto ttycheck; 258 } 259 } 260 261 fflag = 0; 262 263 (void)setpriority(PRIO_PROCESS, 0, -4); 264 265 p = getpass("Password:"); 266 267 if (pwd) { 268 #if defined(KERBEROS) || defined(KERBEROS5) 269 rval = klogin(pwd, instance, localhost, p); 270 if (rval == 0) 271 authok = 1; 272 else if (rval == 1) { 273 if (pwd->pw_uid != 0) 274 rootlogin = 0; 275 rval = pwcheck(username, p, salt, pwd->pw_passwd); 276 } 277 #else 278 rval = pwcheck(username, p, salt, pwd->pw_passwd); 279 #endif 280 } 281 bzero(p, strlen(p)); 282 283 (void)setpriority(PRIO_PROCESS, 0, 0); 284 285 ttycheck: 286 /* 287 * If trying to log in as root without Kerberos, 288 * but with insecure terminal, refuse the login attempt. 289 */ 290 #if defined(KERBEROS) || defined(KERBEROS5) 291 if (authok == 0) 292 #endif 293 if (pwd && !rval && rootlogin && !rootterm(tty)) { 294 (void)fprintf(stderr, 295 "%s login refused on this terminal.\n", 296 pwd->pw_name); 297 if (hostname) 298 syslog(LOG_NOTICE, 299 "LOGIN %s REFUSED FROM %s ON TTY %s", 300 pwd->pw_name, hostname, tty); 301 else 302 syslog(LOG_NOTICE, 303 "LOGIN %s REFUSED ON TTY %s", 304 pwd->pw_name, tty); 305 continue; 306 } 307 308 if (pwd && !rval) 309 break; 310 311 (void)printf("Login incorrect\n"); 312 failures++; 313 /* we allow 10 tries, but after 3 we start backing off */ 314 if (++cnt > 3) { 315 if (cnt >= 10) { 316 badlogin(username); 317 sleepexit(1); 318 } 319 sleep((u_int)((cnt - 3) * 5)); 320 } 321 } 322 323 /* committed to login -- turn off timeout */ 324 (void)alarm((u_int)0); 325 326 endpwent(); 327 328 /* if user not super-user, check for disabled logins */ 329 if (!rootlogin) 330 checknologin(); 331 332 if (chdir(pwd->pw_dir) < 0) { 333 (void)printf("No home directory %s!\n", pwd->pw_dir); 334 if (chdir("/")) 335 exit(0); 336 pwd->pw_dir = "/"; 337 (void)printf("Logging in with home = \"/\".\n"); 338 } 339 340 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 341 342 if (pwd->pw_change || pwd->pw_expire) 343 (void)gettimeofday(&tp, (struct timezone *)NULL); 344 if (pwd->pw_change) 345 if (tp.tv_sec >= pwd->pw_change) { 346 (void)printf("Sorry -- your password has expired.\n"); 347 sleepexit(1); 348 } else if (pwd->pw_change - tp.tv_sec < 349 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 350 (void)printf("Warning: your password expires on %s", 351 ctime(&pwd->pw_change)); 352 if (pwd->pw_expire) 353 if (tp.tv_sec >= pwd->pw_expire) { 354 (void)printf("Sorry -- your account has expired.\n"); 355 sleepexit(1); 356 } else if (pwd->pw_expire - tp.tv_sec < 357 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 358 (void)printf("Warning: your account expires on %s", 359 ctime(&pwd->pw_expire)); 360 361 /* Nothing else left to fail -- really log in. */ 362 bzero((void *)&utmp, sizeof(utmp)); 363 (void)time(&utmp.ut_time); 364 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 365 if (hostname) 366 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 367 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 368 login(&utmp); 369 370 dolastlog(quietlog); 371 372 (void)chown(ttyn, pwd->pw_uid, 373 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 374 #if defined(KERBEROS) || defined(KERBEROS5) 375 /* Fork so that we can call kdestroy */ 376 if (krbtkfile_env) 377 dofork(); 378 #endif 379 (void)setgid(pwd->pw_gid); 380 381 initgroups(username, pwd->pw_gid); 382 383 if (*pwd->pw_shell == '\0') 384 pwd->pw_shell = _PATH_BSHELL; 385 386 /* Destroy environment unless user has requested its preservation. */ 387 if (!pflag) 388 environ = envinit; 389 (void)setenv("HOME", pwd->pw_dir, 1); 390 (void)setenv("SHELL", pwd->pw_shell, 1); 391 if (term[0] == '\0') 392 (void)strncpy(term, stypeof(tty), sizeof(term)); 393 (void)setenv("TERM", term, 0); 394 (void)setenv("LOGNAME", pwd->pw_name, 1); 395 (void)setenv("USER", pwd->pw_name, 1); 396 (void)setenv("PATH", _PATH_DEFPATH, 0); 397 #ifdef KERBEROS 398 if (krbtkfile_env) 399 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 400 #endif 401 #ifdef KERBEROS5 402 if (krbtkfile_env) 403 (void)setenv("KRB5CCNAME", krbtkfile_env, 1); 404 #endif 405 406 if (tty[sizeof("tty")-1] == 'd') 407 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 408 409 /* If fflag is on, assume caller/authenticator has logged root login. */ 410 if (rootlogin && fflag == 0) 411 if (hostname) 412 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 413 username, tty, hostname); 414 else 415 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 416 417 #if defined(KERBEROS) || defined(KERBEROS5) 418 if (!quietlog && notickets == 1) 419 (void)printf("Warning: no Kerberos tickets issued.\n"); 420 #endif 421 422 if (!quietlog) { 423 (void)printf("%s\n\t%s %s\n\n", 424 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993", 425 "The Regents of the University of California. ", 426 "All rights reserved."); 427 motd(); 428 (void)snprintf(tbuf, 429 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 430 if (stat(tbuf, &st) == 0 && st.st_size != 0) 431 (void)printf("You have %smail.\n", 432 (st.st_mtime > st.st_atime) ? "new " : ""); 433 } 434 435 (void)signal(SIGALRM, SIG_DFL); 436 (void)signal(SIGQUIT, SIG_DFL); 437 (void)signal(SIGINT, SIG_DFL); 438 (void)signal(SIGTSTP, SIG_IGN); 439 440 tbuf[0] = '-'; 441 (void)strcpy(tbuf + 1, (p = rindex(pwd->pw_shell, '/')) ? 442 p + 1 : pwd->pw_shell); 443 444 if (setlogin(pwd->pw_name) < 0) 445 syslog(LOG_ERR, "setlogin() failure: %m"); 446 447 /* Discard permissions last so can't get killed and drop core. */ 448 if (rootlogin) 449 (void) setuid(0); 450 else 451 (void) setuid(pwd->pw_uid); 452 453 execlp(pwd->pw_shell, tbuf, 0); 454 (void)fprintf(stderr, "%s: %s\n", pwd->pw_shell, strerror(errno)); 455 exit(1); 456 } 457 458 int 459 pwcheck(user, p, salt, passwd) 460 char *user, *p, *salt, *passwd; 461 { 462 #ifdef SKEY 463 if (strcasecmp(p, "s/key") == 0) { 464 if (skey_haskey(user)) { 465 fprintf(stderr, "You have no s/key. "); 466 return 1; 467 } else { 468 return skey_authenticate(user); 469 } 470 } 471 #endif 472 return strcmp(crypt(p, salt), passwd); 473 } 474 475 #if defined(KERBEROS) || defined(KERBEROS5) 476 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 477 #else 478 #define NBUFSIZ (UT_NAMESIZE + 1) 479 #endif 480 481 #if defined(KERBEROS) || defined(KERBEROS5) 482 /* 483 * This routine handles cleanup stuff, and the like. 484 * It exists only in the child process. 485 */ 486 #include <sys/wait.h> 487 void 488 dofork() 489 { 490 int child; 491 492 if (!(child = fork())) 493 return; /* Child process */ 494 495 /* Setup stuff? This would be things we could do in parallel with login */ 496 (void) chdir("/"); /* Let's not keep the fs busy... */ 497 498 /* If we're the parent, watch the child until it dies */ 499 while (wait(0) != child) 500 ; 501 502 /* Cleanup stuff */ 503 /* Run kdestroy to destroy tickets */ 504 kdestroy(); 505 506 /* Leave */ 507 exit(0); 508 } 509 #endif 510 511 void 512 getloginname() 513 { 514 register int ch; 515 register char *p; 516 static char nbuf[NBUFSIZ]; 517 518 for (;;) { 519 (void)printf("login: "); 520 for (p = nbuf; (ch = getchar()) != '\n'; ) { 521 if (ch == EOF) { 522 badlogin(username); 523 exit(0); 524 } 525 if (p < nbuf + (NBUFSIZ - 1)) 526 *p++ = ch; 527 } 528 if (p > nbuf) 529 if (nbuf[0] == '-') 530 (void)fprintf(stderr, 531 "login names may not start with '-'.\n"); 532 else { 533 *p = '\0'; 534 username = nbuf; 535 break; 536 } 537 } 538 } 539 540 int 541 rootterm(ttyn) 542 char *ttyn; 543 { 544 struct ttyent *t; 545 546 return((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 547 } 548 549 jmp_buf motdinterrupt; 550 551 void 552 motd() 553 { 554 register int fd, nchars; 555 sig_t oldint; 556 char tbuf[8192]; 557 558 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 559 return; 560 oldint = signal(SIGINT, sigint); 561 if (setjmp(motdinterrupt) == 0) 562 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 563 (void)write(fileno(stdout), tbuf, nchars); 564 (void)signal(SIGINT, oldint); 565 (void)close(fd); 566 } 567 568 /* ARGSUSED */ 569 void 570 sigint(signo) 571 int signo; 572 { 573 longjmp(motdinterrupt, 1); 574 } 575 576 /* ARGSUSED */ 577 void 578 timedout(signo) 579 int signo; 580 { 581 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 582 exit(0); 583 } 584 585 void 586 checknologin() 587 { 588 register int fd, nchars; 589 char tbuf[8192]; 590 591 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 592 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 593 (void)write(fileno(stdout), tbuf, nchars); 594 sleepexit(0); 595 } 596 } 597 598 void 599 dolastlog(quiet) 600 int quiet; 601 { 602 struct lastlog ll; 603 int fd; 604 605 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 606 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 607 if (!quiet) { 608 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 609 ll.ll_time != 0) { 610 (void)printf("Last login: %.*s ", 611 24-5, (char *)ctime(&ll.ll_time)); 612 if (*ll.ll_host != '\0') 613 (void)printf("from %.*s\n", 614 (int)sizeof(ll.ll_host), 615 ll.ll_host); 616 else 617 (void)printf("on %.*s\n", 618 (int)sizeof(ll.ll_line), 619 ll.ll_line); 620 } 621 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 622 } 623 bzero((void *)&ll, sizeof(ll)); 624 (void)time(&ll.ll_time); 625 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 626 if (hostname) 627 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 628 (void)write(fd, (char *)&ll, sizeof(ll)); 629 (void)close(fd); 630 } 631 } 632 633 void 634 badlogin(name) 635 char *name; 636 { 637 if (failures == 0) 638 return; 639 if (hostname) { 640 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 641 failures, failures > 1 ? "S" : "", hostname); 642 syslog(LOG_AUTHPRIV|LOG_NOTICE, 643 "%d LOGIN FAILURE%s FROM %s, %s", 644 failures, failures > 1 ? "S" : "", hostname, name); 645 } else { 646 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 647 failures, failures > 1 ? "S" : "", tty); 648 syslog(LOG_AUTHPRIV|LOG_NOTICE, 649 "%d LOGIN FAILURE%s ON %s, %s", 650 failures, failures > 1 ? "S" : "", tty, name); 651 } 652 } 653 654 #undef UNKNOWN 655 #define UNKNOWN "su" 656 657 char * 658 stypeof(ttyid) 659 char *ttyid; 660 { 661 struct ttyent *t; 662 663 return(ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 664 } 665 666 void 667 sleepexit(eval) 668 int eval; 669 { 670 (void)sleep((u_int)5); 671 exit(eval); 672 } 673
Indexes created Tue Sep 30 20:09:53 GMT 2025