login.c revision 1.19
1 /* $NetBSD: login.c,v 1.19 1997/06/23 11:19:10 veego 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 1.19 1997/06/23 11:19:10 veego 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 <skey.h> 69 #include <stdlib.h> 70 #include <string.h> 71 #include <syslog.h> 72 #include <ttyent.h> 73 #include <tzfile.h> 74 #include <unistd.h> 75 #include <utmp.h> 76 #include <util.h> 77 78 #include "pathnames.h" 79 80 void badlogin __P((char *)); 81 void checknologin __P((void)); 82 void dolastlog __P((int)); 83 void getloginname __P((void)); 84 void motd __P((void)); 85 int rootterm __P((char *)); 86 void sigint __P((int)); 87 void sleepexit __P((int)); 88 char *stypeof __P((char *)); 89 void timedout __P((int)); 90 int pwcheck __P((char *, char *, char *, char *)); 91 #if defined(KERBEROS) || defined(KERBEROS5) 92 int klogin __P((struct passwd *, char *, char *, char *)); 93 void kdestroy __P((void)); 94 void dofork __P((void)); 95 #endif 96 97 extern void login __P((struct utmp *)); 98 99 #define TTYGRPNAME "tty" /* name of group to own ttys */ 100 101 /* 102 * This bounds the time given to login. Not a define so it can 103 * be patched on machines where it's too small. 104 */ 105 u_int timeout = 300; 106 107 #if defined(KERBEROS) || defined(KERBEROS5) 108 int notickets = 1; 109 char *instance; 110 char *krbtkfile_env; 111 int authok; 112 #endif 113 114 struct passwd *pwd; 115 int failures; 116 char term[64], *envinit[1], *hostname, *username, *tty; 117 118 int 119 main(argc, argv) 120 int argc; 121 char *argv[]; 122 { 123 extern char **environ; 124 struct group *gr; 125 struct stat st; 126 struct timeval tp; 127 struct utmp utmp; 128 int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval; 129 uid_t uid; 130 char *domain, *p, *salt, *ttyn; 131 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 132 char localhost[MAXHOSTNAMELEN]; 133 134 (void)signal(SIGALRM, timedout); 135 (void)alarm(timeout); 136 (void)signal(SIGQUIT, SIG_IGN); 137 (void)signal(SIGINT, SIG_IGN); 138 (void)setpriority(PRIO_PROCESS, 0, 0); 139 140 openlog("login", LOG_ODELAY, LOG_AUTH); 141 142 /* 143 * -p is used by getty to tell login not to destroy the environment 144 * -f is used to skip a second login authentication 145 * -h is used by other servers to pass the name of the remote 146 * host to login so that it may be placed in utmp and wtmp 147 */ 148 domain = NULL; 149 if (gethostname(localhost, sizeof(localhost)) < 0) 150 syslog(LOG_ERR, "couldn't get local hostname: %m"); 151 else 152 domain = strchr(localhost, '.'); 153 154 fflag = hflag = pflag = 0; 155 uid = getuid(); 156 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 157 switch (ch) { 158 case 'f': 159 fflag = 1; 160 break; 161 case 'h': 162 if (uid) 163 errx(1, "-h option: %s", strerror(EPERM)); 164 hflag = 1; 165 if (domain && (p = strchr(optarg, '.')) && 166 strcasecmp(p, domain) == 0) 167 *p = 0; 168 hostname = optarg; 169 break; 170 case 'p': 171 pflag = 1; 172 break; 173 case '?': 174 default: 175 if (!uid) 176 syslog(LOG_ERR, "invalid flag %c", ch); 177 (void)fprintf(stderr, 178 "usage: login [-fp] [-h hostname] [username]\n"); 179 exit(1); 180 } 181 argc -= optind; 182 argv += optind; 183 184 if (*argv) { 185 username = *argv; 186 ask = 0; 187 } else 188 ask = 1; 189 190 for (cnt = getdtablesize(); cnt > 2; cnt--) 191 (void)close(cnt); 192 193 ttyn = ttyname(STDIN_FILENO); 194 if (ttyn == NULL || *ttyn == '\0') { 195 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 196 ttyn = tname; 197 } 198 if ((tty = strrchr(ttyn, '/'))) 199 ++tty; 200 else 201 tty = ttyn; 202 203 for (cnt = 0;; ask = 1) { 204 #if defined(KERBEROS) || defined(KERBEROS5) 205 kdestroy(); 206 #endif 207 if (ask) { 208 fflag = 0; 209 getloginname(); 210 } 211 rootlogin = 0; 212 #ifdef KERBEROS 213 if ((instance = strchr(username, '.')) != NULL) { 214 if (strncmp(instance, ".root", 5) == 0) 215 rootlogin = 1; 216 *instance++ = '\0'; 217 } else 218 instance = ""; 219 #endif 220 #ifdef KERBEROS5 221 if ((instance = strchr(username, '/')) != NULL) { 222 if (strncmp(instance, "/root", 5) == 0) 223 rootlogin = 1; 224 *instance++ = '\0'; 225 } else 226 instance = ""; 227 #endif 228 if (strlen(username) > MAXLOGNAME) 229 username[MAXLOGNAME] = '\0'; 230 231 /* 232 * Note if trying multiple user names; log failures for 233 * previous user name, but don't bother logging one failure 234 * for nonexistent name (mistyped username). 235 */ 236 if (failures && strcmp(tbuf, username)) { 237 if (failures > (pwd ? 0 : 1)) 238 badlogin(tbuf); 239 failures = 0; 240 } 241 (void)strncpy(tbuf, username, sizeof(tbuf) - 1); 242 243 if ((pwd = getpwnam(username))) 244 salt = pwd->pw_passwd; 245 else 246 salt = "xx"; 247 248 /* 249 * if we have a valid account name, and it doesn't have a 250 * password, or the -f option was specified and the caller 251 * is root or the caller isn't changing their uid, don't 252 * authenticate. 253 */ 254 if (pwd) { 255 if (pwd->pw_uid == 0) 256 rootlogin = 1; 257 258 if (fflag && (uid == 0 || uid == pwd->pw_uid)) { 259 /* already authenticated */ 260 break; 261 } else if (pwd->pw_passwd[0] == '\0') { 262 /* pretend password okay */ 263 rval = 0; 264 goto ttycheck; 265 } 266 } 267 268 fflag = 0; 269 270 (void)setpriority(PRIO_PROCESS, 0, -4); 271 272 p = getpass("Password:"); 273 274 if (pwd) { 275 #if defined(KERBEROS) || defined(KERBEROS5) 276 rval = klogin(pwd, instance, localhost, p); 277 if (rval != 0 && rootlogin && pwd->pw_uid != 0) 278 rootlogin = 0; 279 if (rval == 0) 280 authok = 1; 281 else if (rval == 1) { 282 if (pwd->pw_uid != 0) 283 rootlogin = 0; 284 rval = pwcheck(username, p, salt, pwd->pw_passwd); 285 } 286 #else 287 rval = pwcheck(username, p, salt, pwd->pw_passwd); 288 #endif 289 } 290 memset(p, 0, strlen(p)); 291 292 (void)setpriority(PRIO_PROCESS, 0, 0); 293 294 ttycheck: 295 /* 296 * If trying to log in as root without Kerberos, 297 * but with insecure terminal, refuse the login attempt. 298 */ 299 #if defined(KERBEROS) || defined(KERBEROS5) 300 if (authok == 0) 301 #endif 302 if (pwd && !rval && rootlogin && !rootterm(tty)) { 303 (void)fprintf(stderr, 304 "%s login refused on this terminal.\n", 305 pwd->pw_name); 306 if (hostname) 307 syslog(LOG_NOTICE, 308 "LOGIN %s REFUSED FROM %s ON TTY %s", 309 pwd->pw_name, hostname, tty); 310 else 311 syslog(LOG_NOTICE, 312 "LOGIN %s REFUSED ON TTY %s", 313 pwd->pw_name, tty); 314 continue; 315 } 316 317 if (pwd && !rval) 318 break; 319 320 (void)printf("Login incorrect\n"); 321 failures++; 322 /* we allow 10 tries, but after 3 we start backing off */ 323 if (++cnt > 3) { 324 if (cnt >= 10) { 325 badlogin(username); 326 sleepexit(1); 327 } 328 sleep((u_int)((cnt - 3) * 5)); 329 } 330 } 331 332 /* committed to login -- turn off timeout */ 333 (void)alarm((u_int)0); 334 335 endpwent(); 336 337 /* if user not super-user, check for disabled logins */ 338 if (!rootlogin) 339 checknologin(); 340 341 if (chdir(pwd->pw_dir) < 0) { 342 (void)printf("No home directory %s!\n", pwd->pw_dir); 343 if (chdir("/")) 344 exit(0); 345 pwd->pw_dir = "/"; 346 (void)printf("Logging in with home = \"/\".\n"); 347 } 348 349 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 350 351 if (pwd->pw_change || pwd->pw_expire) 352 (void)gettimeofday(&tp, (struct timezone *)NULL); 353 if (pwd->pw_change) 354 if (tp.tv_sec >= pwd->pw_change) { 355 (void)printf("Sorry -- your password has expired.\n"); 356 sleepexit(1); 357 } else if (pwd->pw_change - tp.tv_sec < 358 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 359 (void)printf("Warning: your password expires on %s", 360 ctime(&pwd->pw_change)); 361 if (pwd->pw_expire) 362 if (tp.tv_sec >= pwd->pw_expire) { 363 (void)printf("Sorry -- your account has expired.\n"); 364 sleepexit(1); 365 } else if (pwd->pw_expire - tp.tv_sec < 366 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 367 (void)printf("Warning: your account expires on %s", 368 ctime(&pwd->pw_expire)); 369 370 /* Nothing else left to fail -- really log in. */ 371 memset((void *)&utmp, 0, sizeof(utmp)); 372 (void)time(&utmp.ut_time); 373 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 374 if (hostname) 375 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 376 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 377 login(&utmp); 378 379 dolastlog(quietlog); 380 381 (void)chown(ttyn, pwd->pw_uid, 382 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 383 384 if (ttyaction(ttyn, "login", pwd->pw_name)) 385 (void)printf("Warning: ttyaction failed.\n"); 386 387 #if defined(KERBEROS) || defined(KERBEROS5) 388 /* Fork so that we can call kdestroy */ 389 if (krbtkfile_env) 390 dofork(); 391 #endif 392 (void)setgid(pwd->pw_gid); 393 394 initgroups(username, pwd->pw_gid); 395 396 if (*pwd->pw_shell == '\0') 397 pwd->pw_shell = _PATH_BSHELL; 398 399 /* Destroy environment unless user has requested its preservation. */ 400 if (!pflag) 401 environ = envinit; 402 (void)setenv("HOME", pwd->pw_dir, 1); 403 (void)setenv("SHELL", pwd->pw_shell, 1); 404 if (term[0] == '\0') 405 (void)strncpy(term, stypeof(tty), sizeof(term)); 406 (void)setenv("TERM", term, 0); 407 (void)setenv("LOGNAME", pwd->pw_name, 1); 408 (void)setenv("USER", pwd->pw_name, 1); 409 (void)setenv("PATH", _PATH_DEFPATH, 0); 410 #ifdef KERBEROS 411 if (krbtkfile_env) 412 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 413 #endif 414 #ifdef KERBEROS5 415 if (krbtkfile_env) 416 (void)setenv("KRB5CCNAME", krbtkfile_env, 1); 417 #endif 418 419 if (tty[sizeof("tty")-1] == 'd') 420 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 421 422 /* If fflag is on, assume caller/authenticator has logged root login. */ 423 if (rootlogin && fflag == 0) 424 if (hostname) 425 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 426 username, tty, hostname); 427 else 428 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 429 430 #if defined(KERBEROS) || defined(KERBEROS5) 431 if (!quietlog && notickets == 1) 432 (void)printf("Warning: no Kerberos tickets issued.\n"); 433 #endif 434 435 if (!quietlog) { 436 (void)printf("%s\n\t%s %s\n\n", 437 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", 438 "The Regents of the University of California. ", 439 "All rights reserved."); 440 motd(); 441 (void)snprintf(tbuf, 442 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 443 if (stat(tbuf, &st) == 0 && st.st_size != 0) 444 (void)printf("You have %smail.\n", 445 (st.st_mtime > st.st_atime) ? "new " : ""); 446 } 447 448 (void)signal(SIGALRM, SIG_DFL); 449 (void)signal(SIGQUIT, SIG_DFL); 450 (void)signal(SIGINT, SIG_DFL); 451 (void)signal(SIGTSTP, SIG_IGN); 452 453 tbuf[0] = '-'; 454 (void)strncpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? 455 p + 1 : pwd->pw_shell, sizeof(tbuf) - 2); 456 457 if (setlogin(pwd->pw_name) < 0) 458 syslog(LOG_ERR, "setlogin() failure: %m"); 459 460 /* Discard permissions last so can't get killed and drop core. */ 461 if (rootlogin) 462 (void) setuid(0); 463 else 464 (void) setuid(pwd->pw_uid); 465 466 execlp(pwd->pw_shell, tbuf, 0); 467 err(1, "%s", pwd->pw_shell); 468 } 469 470 int 471 pwcheck(user, p, salt, passwd) 472 char *user, *p, *salt, *passwd; 473 { 474 #ifdef SKEY 475 if (strcasecmp(p, "s/key") == 0) 476 if (skey_haskey(user)) 477 return 1; 478 else 479 return skey_authenticate(user); 480 #endif 481 return strcmp(crypt(p, salt), passwd); 482 } 483 484 #if defined(KERBEROS) || defined(KERBEROS5) 485 #define NBUFSIZ (MAXLOGNAME + 1 + 5) /* .root suffix */ 486 #else 487 #define NBUFSIZ (MAXLOGNAME + 1) 488 #endif 489 490 #if defined(KERBEROS) || defined(KERBEROS5) 491 /* 492 * This routine handles cleanup stuff, and the like. 493 * It exists only in the child process. 494 */ 495 #include <sys/wait.h> 496 void 497 dofork() 498 { 499 int child; 500 501 if (!(child = fork())) 502 return; /* Child process */ 503 504 /* Setup stuff? This would be things we could do in parallel with login */ 505 (void) chdir("/"); /* Let's not keep the fs busy... */ 506 507 /* If we're the parent, watch the child until it dies */ 508 while (wait(0) != child) 509 ; 510 511 /* Cleanup stuff */ 512 /* Run kdestroy to destroy tickets */ 513 kdestroy(); 514 515 /* Leave */ 516 exit(0); 517 } 518 #endif 519 520 void 521 getloginname() 522 { 523 int ch; 524 char *p; 525 static char nbuf[NBUFSIZ]; 526 527 for (;;) { 528 (void)printf("login: "); 529 for (p = nbuf; (ch = getchar()) != '\n'; ) { 530 if (ch == EOF) { 531 badlogin(username); 532 exit(0); 533 } 534 if (p < nbuf + (NBUFSIZ - 1)) 535 *p++ = ch; 536 } 537 if (p > nbuf) 538 if (nbuf[0] == '-') 539 (void)fprintf(stderr, 540 "login names may not start with '-'.\n"); 541 else { 542 *p = '\0'; 543 username = nbuf; 544 break; 545 } 546 } 547 } 548 549 int 550 rootterm(ttyn) 551 char *ttyn; 552 { 553 struct ttyent *t; 554 555 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 556 } 557 558 jmp_buf motdinterrupt; 559 560 void 561 motd() 562 { 563 int fd, nchars; 564 sig_t oldint; 565 char tbuf[8192]; 566 567 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 568 return; 569 oldint = signal(SIGINT, sigint); 570 if (setjmp(motdinterrupt) == 0) 571 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 572 (void)write(fileno(stdout), tbuf, nchars); 573 (void)signal(SIGINT, oldint); 574 (void)close(fd); 575 } 576 577 /* ARGSUSED */ 578 void 579 sigint(signo) 580 int signo; 581 { 582 longjmp(motdinterrupt, 1); 583 } 584 585 /* ARGSUSED */ 586 void 587 timedout(signo) 588 int signo; 589 { 590 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 591 exit(0); 592 } 593 594 void 595 checknologin() 596 { 597 int fd, nchars; 598 char tbuf[8192]; 599 600 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 601 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 602 (void)write(fileno(stdout), tbuf, nchars); 603 sleepexit(0); 604 } 605 } 606 607 void 608 dolastlog(quiet) 609 int quiet; 610 { 611 struct lastlog ll; 612 int fd; 613 614 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 615 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 616 if (!quiet) { 617 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 618 ll.ll_time != 0) { 619 (void)printf("Last login: %.*s ", 620 24-5, (char *)ctime(&ll.ll_time)); 621 if (*ll.ll_host != '\0') 622 (void)printf("from %.*s\n", 623 (int)sizeof(ll.ll_host), 624 ll.ll_host); 625 else 626 (void)printf("on %.*s\n", 627 (int)sizeof(ll.ll_line), 628 ll.ll_line); 629 } 630 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 631 } 632 memset((void *)&ll, 0, sizeof(ll)); 633 (void)time(&ll.ll_time); 634 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 635 if (hostname) 636 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 637 (void)write(fd, (char *)&ll, sizeof(ll)); 638 (void)close(fd); 639 } 640 } 641 642 void 643 badlogin(name) 644 char *name; 645 { 646 if (failures == 0) 647 return; 648 if (hostname) { 649 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 650 failures, failures > 1 ? "S" : "", hostname); 651 syslog(LOG_AUTHPRIV|LOG_NOTICE, 652 "%d LOGIN FAILURE%s FROM %s, %s", 653 failures, failures > 1 ? "S" : "", hostname, name); 654 } else { 655 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 656 failures, failures > 1 ? "S" : "", tty); 657 syslog(LOG_AUTHPRIV|LOG_NOTICE, 658 "%d LOGIN FAILURE%s ON %s, %s", 659 failures, failures > 1 ? "S" : "", tty, name); 660 } 661 } 662 663 #undef UNKNOWN 664 #define UNKNOWN "su" 665 666 char * 667 stypeof(ttyid) 668 char *ttyid; 669 { 670 struct ttyent *t; 671 672 return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 673 } 674 675 void 676 sleepexit(eval) 677 int eval; 678 { 679 (void)sleep(5); 680 exit(eval); 681 } 682
Indexes created Wed Oct 01 07:09:59 GMT 2025