login.c revision 1.12
1 /* $NetBSD: login.c,v 1.12 1994/12/23 06:53:01 jtc Exp $ */ 2 3 /*- 4 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 static char copyright[] = 38 "@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\ 39 The Regents of the University of California. All rights reserved.\n"; 40 #endif /* not lint */ 41 42 #ifndef lint 43 #if 0 44 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; 45 #endif 46 static char rcsid[] = "$NetBSD: login.c,v 1.12 1994/12/23 06:53:01 jtc Exp $"; 47 #endif /* not lint */ 48 49 /* 50 * login [ name ] 51 * login -h hostname (for telnetd, etc.) 52 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 53 */ 54 55 #include <sys/param.h> 56 #include <sys/stat.h> 57 #include <sys/time.h> 58 #include <sys/resource.h> 59 #include <sys/file.h> 60 61 #include <err.h> 62 #include <errno.h> 63 #include <grp.h> 64 #include <pwd.h> 65 #include <setjmp.h> 66 #include <signal.h> 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <syslog.h> 71 #include <ttyent.h> 72 #include <tzfile.h> 73 #include <unistd.h> 74 #include <utmp.h> 75 76 #include "pathnames.h" 77 78 void badlogin __P((char *)); 79 void checknologin __P((void)); 80 void dolastlog __P((int)); 81 void getloginname __P((void)); 82 void motd __P((void)); 83 int rootterm __P((char *)); 84 void sigint __P((int)); 85 void sleepexit __P((int)); 86 char *stypeof __P((char *)); 87 void timedout __P((int)); 88 int pwcheck __P((char *, char *, char *, char *)); 89 #if defined(KERBEROS) || defined(KERBEROS5) 90 int klogin __P((struct passwd *, char *, char *, char *)); 91 void kdestroy __P((void)); 92 void dofork __P((void)); 93 #endif 94 95 extern void login __P((struct utmp *)); 96 97 #define TTYGRPNAME "tty" /* name of group to own ttys */ 98 99 /* 100 * This bounds the time given to login. Not a define so it can 101 * be patched on machines where it's too small. 102 */ 103 u_int timeout = 300; 104 105 #if defined(KERBEROS) || defined(KERBEROS5) 106 int notickets = 1; 107 char *instance; 108 char *krbtkfile_env; 109 int authok; 110 #endif 111 112 struct passwd *pwd; 113 int failures; 114 char term[64], *envinit[1], *hostname, *username, *tty; 115 116 int 117 main(argc, argv) 118 int argc; 119 char *argv[]; 120 { 121 extern char **environ; 122 struct group *gr; 123 struct stat st; 124 struct timeval tp; 125 struct utmp utmp; 126 int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval; 127 uid_t uid; 128 char *domain, *p, *salt, *ttyn; 129 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 130 char localhost[MAXHOSTNAMELEN]; 131 132 (void)signal(SIGALRM, timedout); 133 (void)alarm(timeout); 134 (void)signal(SIGQUIT, SIG_IGN); 135 (void)signal(SIGINT, SIG_IGN); 136 (void)setpriority(PRIO_PROCESS, 0, 0); 137 138 openlog("login", LOG_ODELAY, LOG_AUTH); 139 140 /* 141 * -p is used by getty to tell login not to destroy the environment 142 * -f is used to skip a second login authentication 143 * -h is used by other servers to pass the name of the remote 144 * host to login so that it may be placed in utmp and wtmp 145 */ 146 domain = NULL; 147 if (gethostname(localhost, sizeof(localhost)) < 0) 148 syslog(LOG_ERR, "couldn't get local hostname: %m"); 149 else 150 domain = strchr(localhost, '.'); 151 152 fflag = hflag = pflag = 0; 153 uid = getuid(); 154 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 155 switch (ch) { 156 case 'f': 157 fflag = 1; 158 break; 159 case 'h': 160 if (uid) 161 errx(1, "-h option: %s", strerror(EPERM)); 162 hflag = 1; 163 if (domain && (p = strchr(optarg, '.')) && 164 strcasecmp(p, domain) == 0) 165 *p = 0; 166 hostname = optarg; 167 break; 168 case 'p': 169 pflag = 1; 170 break; 171 case '?': 172 default: 173 if (!uid) 174 syslog(LOG_ERR, "invalid flag %c", ch); 175 (void)fprintf(stderr, 176 "usage: login [-fp] [-h hostname] [username]\n"); 177 exit(1); 178 } 179 argc -= optind; 180 argv += optind; 181 182 if (*argv) { 183 username = *argv; 184 ask = 0; 185 } else 186 ask = 1; 187 188 for (cnt = getdtablesize(); cnt > 2; cnt--) 189 (void)close(cnt); 190 191 ttyn = ttyname(STDIN_FILENO); 192 if (ttyn == NULL || *ttyn == '\0') { 193 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 194 ttyn = tname; 195 } 196 if (tty = strrchr(ttyn, '/')) 197 ++tty; 198 else 199 tty = ttyn; 200 201 for (cnt = 0;; ask = 1) { 202 #if defined(KERBEROS) || defined(KERBEROS5) 203 kdestroy(); 204 #endif 205 if (ask) { 206 fflag = 0; 207 getloginname(); 208 } 209 rootlogin = 0; 210 #ifdef KERBEROS 211 if ((instance = strchr(username, '.')) != NULL) { 212 if (strncmp(instance, ".root", 5) == 0) 213 rootlogin = 1; 214 *instance++ = '\0'; 215 } else 216 instance = ""; 217 #endif 218 #ifdef KERBEROS5 219 if ((instance = strchr(username, '/')) != NULL) { 220 if (strncmp(instance, "/root", 5) == 0) 221 rootlogin = 1; 222 *instance++ = '\0'; 223 } else 224 instance = ""; 225 #endif 226 if (strlen(username) > UT_NAMESIZE) 227 username[UT_NAMESIZE] = '\0'; 228 229 /* 230 * Note if trying multiple user names; log failures for 231 * previous user name, but don't bother logging one failure 232 * for nonexistent name (mistyped username). 233 */ 234 if (failures && strcmp(tbuf, username)) { 235 if (failures > (pwd ? 0 : 1)) 236 badlogin(tbuf); 237 failures = 0; 238 } 239 (void)strcpy(tbuf, username); 240 241 if (pwd = getpwnam(username)) 242 salt = pwd->pw_passwd; 243 else 244 salt = "xx"; 245 246 /* 247 * if we have a valid account name, and it doesn't have a 248 * password, or the -f option was specified and the caller 249 * is root or the caller isn't changing their uid, don't 250 * authenticate. 251 */ 252 if (pwd) { 253 if (pwd->pw_uid == 0) 254 rootlogin = 1; 255 256 if (fflag && (uid == 0 || uid == pwd->pw_uid)) { 257 /* already authenticated */ 258 break; 259 } else if (pwd->pw_passwd[0] == '\0') { 260 /* pretend password okay */ 261 rval = 0; 262 goto ttycheck; 263 } 264 } 265 266 fflag = 0; 267 268 (void)setpriority(PRIO_PROCESS, 0, -4); 269 270 p = getpass("Password:"); 271 272 if (pwd) { 273 #if defined(KERBEROS) || defined(KERBEROS5) 274 rval = klogin(pwd, instance, localhost, p); 275 if (rval != 0 && rootlogin && pwd->pw_uid != 0) 276 rootlogin = 0; 277 if (rval == 0) 278 authok = 1; 279 else if (rval == 1) { 280 if (pwd->pw_uid != 0) 281 rootlogin = 0; 282 rval = pwcheck(username, p, salt, pwd->pw_passwd); 283 } 284 #else 285 rval = pwcheck(username, p, salt, pwd->pw_passwd); 286 #endif 287 } 288 memset(p, 0, strlen(p)); 289 290 (void)setpriority(PRIO_PROCESS, 0, 0); 291 292 ttycheck: 293 /* 294 * If trying to log in as root without Kerberos, 295 * but with insecure terminal, refuse the login attempt. 296 */ 297 #if defined(KERBEROS) || defined(KERBEROS5) 298 if (authok == 0) 299 #endif 300 if (pwd && !rval && rootlogin && !rootterm(tty)) { 301 (void)fprintf(stderr, 302 "%s login refused on this terminal.\n", 303 pwd->pw_name); 304 if (hostname) 305 syslog(LOG_NOTICE, 306 "LOGIN %s REFUSED FROM %s ON TTY %s", 307 pwd->pw_name, hostname, tty); 308 else 309 syslog(LOG_NOTICE, 310 "LOGIN %s REFUSED ON TTY %s", 311 pwd->pw_name, tty); 312 continue; 313 } 314 315 if (pwd && !rval) 316 break; 317 318 (void)printf("Login incorrect\n"); 319 failures++; 320 /* we allow 10 tries, but after 3 we start backing off */ 321 if (++cnt > 3) { 322 if (cnt >= 10) { 323 badlogin(username); 324 sleepexit(1); 325 } 326 sleep((u_int)((cnt - 3) * 5)); 327 } 328 } 329 330 /* committed to login -- turn off timeout */ 331 (void)alarm((u_int)0); 332 333 endpwent(); 334 335 /* if user not super-user, check for disabled logins */ 336 if (!rootlogin) 337 checknologin(); 338 339 if (chdir(pwd->pw_dir) < 0) { 340 (void)printf("No home directory %s!\n", pwd->pw_dir); 341 if (chdir("/")) 342 exit(0); 343 pwd->pw_dir = "/"; 344 (void)printf("Logging in with home = \"/\".\n"); 345 } 346 347 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 348 349 if (pwd->pw_change || pwd->pw_expire) 350 (void)gettimeofday(&tp, (struct timezone *)NULL); 351 if (pwd->pw_change) 352 if (tp.tv_sec >= pwd->pw_change) { 353 (void)printf("Sorry -- your password has expired.\n"); 354 sleepexit(1); 355 } else if (pwd->pw_change - tp.tv_sec < 356 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 357 (void)printf("Warning: your password expires on %s", 358 ctime(&pwd->pw_change)); 359 if (pwd->pw_expire) 360 if (tp.tv_sec >= pwd->pw_expire) { 361 (void)printf("Sorry -- your account has expired.\n"); 362 sleepexit(1); 363 } else if (pwd->pw_expire - tp.tv_sec < 364 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 365 (void)printf("Warning: your account expires on %s", 366 ctime(&pwd->pw_expire)); 367 368 /* Nothing else left to fail -- really log in. */ 369 memset((void *)&utmp, 0, sizeof(utmp)); 370 (void)time(&utmp.ut_time); 371 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 372 if (hostname) 373 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 374 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 375 login(&utmp); 376 377 dolastlog(quietlog); 378 379 (void)chown(ttyn, pwd->pw_uid, 380 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 381 #if defined(KERBEROS) || defined(KERBEROS5) 382 /* Fork so that we can call kdestroy */ 383 if (krbtkfile_env) 384 dofork(); 385 #endif 386 (void)setgid(pwd->pw_gid); 387 388 initgroups(username, pwd->pw_gid); 389 390 if (*pwd->pw_shell == '\0') 391 pwd->pw_shell = _PATH_BSHELL; 392 393 /* Destroy environment unless user has requested its preservation. */ 394 if (!pflag) 395 environ = envinit; 396 (void)setenv("HOME", pwd->pw_dir, 1); 397 (void)setenv("SHELL", pwd->pw_shell, 1); 398 if (term[0] == '\0') 399 (void)strncpy(term, stypeof(tty), sizeof(term)); 400 (void)setenv("TERM", term, 0); 401 (void)setenv("LOGNAME", pwd->pw_name, 1); 402 (void)setenv("USER", pwd->pw_name, 1); 403 (void)setenv("PATH", _PATH_DEFPATH, 0); 404 #ifdef KERBEROS 405 if (krbtkfile_env) 406 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 407 #endif 408 #ifdef KERBEROS5 409 if (krbtkfile_env) 410 (void)setenv("KRB5CCNAME", krbtkfile_env, 1); 411 #endif 412 413 if (tty[sizeof("tty")-1] == 'd') 414 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 415 416 /* If fflag is on, assume caller/authenticator has logged root login. */ 417 if (rootlogin && fflag == 0) 418 if (hostname) 419 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 420 username, tty, hostname); 421 else 422 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 423 424 #if defined(KERBEROS) || defined(KERBEROS5) 425 if (!quietlog && notickets == 1) 426 (void)printf("Warning: no Kerberos tickets issued.\n"); 427 #endif 428 429 if (!quietlog) { 430 (void)printf("%s\n\t%s %s\n\n", 431 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", 432 "The Regents of the University of California. ", 433 "All rights reserved."); 434 motd(); 435 (void)snprintf(tbuf, 436 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 437 if (stat(tbuf, &st) == 0 && st.st_size != 0) 438 (void)printf("You have %smail.\n", 439 (st.st_mtime > st.st_atime) ? "new " : ""); 440 } 441 442 (void)signal(SIGALRM, SIG_DFL); 443 (void)signal(SIGQUIT, SIG_DFL); 444 (void)signal(SIGINT, SIG_DFL); 445 (void)signal(SIGTSTP, SIG_IGN); 446 447 tbuf[0] = '-'; 448 (void)strcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? 449 p + 1 : pwd->pw_shell); 450 451 if (setlogin(pwd->pw_name) < 0) 452 syslog(LOG_ERR, "setlogin() failure: %m"); 453 454 /* Discard permissions last so can't get killed and drop core. */ 455 if (rootlogin) 456 (void) setuid(0); 457 else 458 (void) setuid(pwd->pw_uid); 459 460 execlp(pwd->pw_shell, tbuf, 0); 461 err(1, "%s", pwd->pw_shell); 462 } 463 464 int 465 pwcheck(user, p, salt, passwd) 466 char *user, *p, *salt, *passwd; 467 { 468 #ifdef SKEY 469 if (strcasecmp(p, "s/key") == 0) { 470 if (skey_haskey(user)) { 471 fprintf(stderr, "You have no s/key. "); 472 return 1; 473 } else { 474 return skey_authenticate(user); 475 } 476 } 477 #endif 478 return strcmp(crypt(p, salt), passwd); 479 } 480 481 #if defined(KERBEROS) || defined(KERBEROS5) 482 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 483 #else 484 #define NBUFSIZ (UT_NAMESIZE + 1) 485 #endif 486 487 #if defined(KERBEROS) || defined(KERBEROS5) 488 /* 489 * This routine handles cleanup stuff, and the like. 490 * It exists only in the child process. 491 */ 492 #include <sys/wait.h> 493 void 494 dofork() 495 { 496 int child; 497 498 if (!(child = fork())) 499 return; /* Child process */ 500 501 /* Setup stuff? This would be things we could do in parallel with login */ 502 (void) chdir("/"); /* Let's not keep the fs busy... */ 503 504 /* If we're the parent, watch the child until it dies */ 505 while (wait(0) != child) 506 ; 507 508 /* Cleanup stuff */ 509 /* Run kdestroy to destroy tickets */ 510 kdestroy(); 511 512 /* Leave */ 513 exit(0); 514 } 515 #endif 516 517 void 518 getloginname() 519 { 520 int ch; 521 char *p; 522 static char nbuf[NBUFSIZ]; 523 524 for (;;) { 525 (void)printf("login: "); 526 for (p = nbuf; (ch = getchar()) != '\n'; ) { 527 if (ch == EOF) { 528 badlogin(username); 529 exit(0); 530 } 531 if (p < nbuf + (NBUFSIZ - 1)) 532 *p++ = ch; 533 } 534 if (p > nbuf) 535 if (nbuf[0] == '-') 536 (void)fprintf(stderr, 537 "login names may not start with '-'.\n"); 538 else { 539 *p = '\0'; 540 username = nbuf; 541 break; 542 } 543 } 544 } 545 546 int 547 rootterm(ttyn) 548 char *ttyn; 549 { 550 struct ttyent *t; 551 552 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 553 } 554 555 jmp_buf motdinterrupt; 556 557 void 558 motd() 559 { 560 int fd, nchars; 561 sig_t oldint; 562 char tbuf[8192]; 563 564 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 565 return; 566 oldint = signal(SIGINT, sigint); 567 if (setjmp(motdinterrupt) == 0) 568 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 569 (void)write(fileno(stdout), tbuf, nchars); 570 (void)signal(SIGINT, oldint); 571 (void)close(fd); 572 } 573 574 /* ARGSUSED */ 575 void 576 sigint(signo) 577 int signo; 578 { 579 longjmp(motdinterrupt, 1); 580 } 581 582 /* ARGSUSED */ 583 void 584 timedout(signo) 585 int signo; 586 { 587 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 588 exit(0); 589 } 590 591 void 592 checknologin() 593 { 594 int fd, nchars; 595 char tbuf[8192]; 596 597 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 598 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 599 (void)write(fileno(stdout), tbuf, nchars); 600 sleepexit(0); 601 } 602 } 603 604 void 605 dolastlog(quiet) 606 int quiet; 607 { 608 struct lastlog ll; 609 int fd; 610 611 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 612 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 613 if (!quiet) { 614 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 615 ll.ll_time != 0) { 616 (void)printf("Last login: %.*s ", 617 24-5, (char *)ctime(&ll.ll_time)); 618 if (*ll.ll_host != '\0') 619 (void)printf("from %.*s\n", 620 (int)sizeof(ll.ll_host), 621 ll.ll_host); 622 else 623 (void)printf("on %.*s\n", 624 (int)sizeof(ll.ll_line), 625 ll.ll_line); 626 } 627 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 628 } 629 memset((void *)&ll, 0, sizeof(ll)); 630 (void)time(&ll.ll_time); 631 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 632 if (hostname) 633 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 634 (void)write(fd, (char *)&ll, sizeof(ll)); 635 (void)close(fd); 636 } 637 } 638 639 void 640 badlogin(name) 641 char *name; 642 { 643 if (failures == 0) 644 return; 645 if (hostname) { 646 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 647 failures, failures > 1 ? "S" : "", hostname); 648 syslog(LOG_AUTHPRIV|LOG_NOTICE, 649 "%d LOGIN FAILURE%s FROM %s, %s", 650 failures, failures > 1 ? "S" : "", hostname, name); 651 } else { 652 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 653 failures, failures > 1 ? "S" : "", tty); 654 syslog(LOG_AUTHPRIV|LOG_NOTICE, 655 "%d LOGIN FAILURE%s ON %s, %s", 656 failures, failures > 1 ? "S" : "", tty, name); 657 } 658 } 659 660 #undef UNKNOWN 661 #define UNKNOWN "su" 662 663 char * 664 stypeof(ttyid) 665 char *ttyid; 666 { 667 struct ttyent *t; 668 669 return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 670 } 671 672 void 673 sleepexit(eval) 674 int eval; 675 { 676 (void)sleep(5); 677 exit(eval); 678 } 679
Indexes created Tue Sep 30 20:09:53 GMT 2025