login.c revision 1.17
1 /* $NetBSD: login.c,v 1.17 1997/02/11 08:15:10 mrg 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 1.17 1997/02/11 08:15:10 mrg 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 #include <util.h> 76 77 #include "pathnames.h" 78 79 void badlogin __P((char *)); 80 void checknologin __P((void)); 81 void dolastlog __P((int)); 82 void getloginname __P((void)); 83 void motd __P((void)); 84 int rootterm __P((char *)); 85 void sigint __P((int)); 86 void sleepexit __P((int)); 87 char *stypeof __P((char *)); 88 void timedout __P((int)); 89 int pwcheck __P((char *, char *, char *, char *)); 90 #if defined(KERBEROS) || defined(KERBEROS5) 91 int klogin __P((struct passwd *, char *, char *, char *)); 92 void kdestroy __P((void)); 93 void dofork __P((void)); 94 #endif 95 96 extern void login __P((struct utmp *)); 97 98 #define TTYGRPNAME "tty" /* name of group to own ttys */ 99 100 /* 101 * This bounds the time given to login. Not a define so it can 102 * be patched on machines where it's too small. 103 */ 104 u_int timeout = 300; 105 106 #if defined(KERBEROS) || defined(KERBEROS5) 107 int notickets = 1; 108 char *instance; 109 char *krbtkfile_env; 110 int authok; 111 #endif 112 113 struct passwd *pwd; 114 int failures; 115 char term[64], *envinit[1], *hostname, *username, *tty; 116 117 int 118 main(argc, argv) 119 int argc; 120 char *argv[]; 121 { 122 extern char **environ; 123 struct group *gr; 124 struct stat st; 125 struct timeval tp; 126 struct utmp utmp; 127 int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval; 128 uid_t uid; 129 char *domain, *p, *salt, *ttyn; 130 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 131 char localhost[MAXHOSTNAMELEN]; 132 133 (void)signal(SIGALRM, timedout); 134 (void)alarm(timeout); 135 (void)signal(SIGQUIT, SIG_IGN); 136 (void)signal(SIGINT, SIG_IGN); 137 (void)setpriority(PRIO_PROCESS, 0, 0); 138 139 openlog("login", LOG_ODELAY, LOG_AUTH); 140 141 /* 142 * -p is used by getty to tell login not to destroy the environment 143 * -f is used to skip a second login authentication 144 * -h is used by other servers to pass the name of the remote 145 * host to login so that it may be placed in utmp and wtmp 146 */ 147 domain = NULL; 148 if (gethostname(localhost, sizeof(localhost)) < 0) 149 syslog(LOG_ERR, "couldn't get local hostname: %m"); 150 else 151 domain = strchr(localhost, '.'); 152 153 fflag = hflag = pflag = 0; 154 uid = getuid(); 155 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 156 switch (ch) { 157 case 'f': 158 fflag = 1; 159 break; 160 case 'h': 161 if (uid) 162 errx(1, "-h option: %s", strerror(EPERM)); 163 hflag = 1; 164 if (domain && (p = strchr(optarg, '.')) && 165 strcasecmp(p, domain) == 0) 166 *p = 0; 167 hostname = optarg; 168 break; 169 case 'p': 170 pflag = 1; 171 break; 172 case '?': 173 default: 174 if (!uid) 175 syslog(LOG_ERR, "invalid flag %c", ch); 176 (void)fprintf(stderr, 177 "usage: login [-fp] [-h hostname] [username]\n"); 178 exit(1); 179 } 180 argc -= optind; 181 argv += optind; 182 183 if (*argv) { 184 username = *argv; 185 ask = 0; 186 } else 187 ask = 1; 188 189 for (cnt = getdtablesize(); cnt > 2; cnt--) 190 (void)close(cnt); 191 192 ttyn = ttyname(STDIN_FILENO); 193 if (ttyn == NULL || *ttyn == '\0') { 194 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 195 ttyn = tname; 196 } 197 if (tty = strrchr(ttyn, '/')) 198 ++tty; 199 else 200 tty = ttyn; 201 202 for (cnt = 0;; ask = 1) { 203 #if defined(KERBEROS) || defined(KERBEROS5) 204 kdestroy(); 205 #endif 206 if (ask) { 207 fflag = 0; 208 getloginname(); 209 } 210 rootlogin = 0; 211 #ifdef KERBEROS 212 if ((instance = strchr(username, '.')) != NULL) { 213 if (strncmp(instance, ".root", 5) == 0) 214 rootlogin = 1; 215 *instance++ = '\0'; 216 } else 217 instance = ""; 218 #endif 219 #ifdef KERBEROS5 220 if ((instance = strchr(username, '/')) != NULL) { 221 if (strncmp(instance, "/root", 5) == 0) 222 rootlogin = 1; 223 *instance++ = '\0'; 224 } else 225 instance = ""; 226 #endif 227 if (strlen(username) > MAXLOGNAME) 228 username[MAXLOGNAME] = '\0'; 229 230 /* 231 * Note if trying multiple user names; log failures for 232 * previous user name, but don't bother logging one failure 233 * for nonexistent name (mistyped username). 234 */ 235 if (failures && strcmp(tbuf, username)) { 236 if (failures > (pwd ? 0 : 1)) 237 badlogin(tbuf); 238 failures = 0; 239 } 240 (void)strncpy(tbuf, username, sizeof(tbuf) - 1); 241 242 if (pwd = getpwnam(username)) 243 salt = pwd->pw_passwd; 244 else 245 salt = "xx"; 246 247 /* 248 * if we have a valid account name, and it doesn't have a 249 * password, or the -f option was specified and the caller 250 * is root or the caller isn't changing their uid, don't 251 * authenticate. 252 */ 253 if (pwd) { 254 if (pwd->pw_uid == 0) 255 rootlogin = 1; 256 257 if (fflag && (uid == 0 || uid == pwd->pw_uid)) { 258 /* already authenticated */ 259 break; 260 } else if (pwd->pw_passwd[0] == '\0') { 261 /* pretend password okay */ 262 rval = 0; 263 goto ttycheck; 264 } 265 } 266 267 fflag = 0; 268 269 (void)setpriority(PRIO_PROCESS, 0, -4); 270 271 p = getpass("Password:"); 272 273 if (pwd) { 274 #if defined(KERBEROS) || defined(KERBEROS5) 275 rval = klogin(pwd, instance, localhost, p); 276 if (rval != 0 && rootlogin && pwd->pw_uid != 0) 277 rootlogin = 0; 278 if (rval == 0) 279 authok = 1; 280 else if (rval == 1) { 281 if (pwd->pw_uid != 0) 282 rootlogin = 0; 283 rval = pwcheck(username, p, salt, pwd->pw_passwd); 284 } 285 #else 286 rval = pwcheck(username, p, salt, pwd->pw_passwd); 287 #endif 288 } 289 memset(p, 0, strlen(p)); 290 291 (void)setpriority(PRIO_PROCESS, 0, 0); 292 293 ttycheck: 294 /* 295 * If trying to log in as root without Kerberos, 296 * but with insecure terminal, refuse the login attempt. 297 */ 298 #if defined(KERBEROS) || defined(KERBEROS5) 299 if (authok == 0) 300 #endif 301 if (pwd && !rval && rootlogin && !rootterm(tty)) { 302 (void)fprintf(stderr, 303 "%s login refused on this terminal.\n", 304 pwd->pw_name); 305 if (hostname) 306 syslog(LOG_NOTICE, 307 "LOGIN %s REFUSED FROM %s ON TTY %s", 308 pwd->pw_name, hostname, tty); 309 else 310 syslog(LOG_NOTICE, 311 "LOGIN %s REFUSED ON TTY %s", 312 pwd->pw_name, tty); 313 continue; 314 } 315 316 if (pwd && !rval) 317 break; 318 319 (void)printf("Login incorrect\n"); 320 failures++; 321 /* we allow 10 tries, but after 3 we start backing off */ 322 if (++cnt > 3) { 323 if (cnt >= 10) { 324 badlogin(username); 325 sleepexit(1); 326 } 327 sleep((u_int)((cnt - 3) * 5)); 328 } 329 } 330 331 /* committed to login -- turn off timeout */ 332 (void)alarm((u_int)0); 333 334 endpwent(); 335 336 /* if user not super-user, check for disabled logins */ 337 if (!rootlogin) 338 checknologin(); 339 340 if (chdir(pwd->pw_dir) < 0) { 341 (void)printf("No home directory %s!\n", pwd->pw_dir); 342 if (chdir("/")) 343 exit(0); 344 pwd->pw_dir = "/"; 345 (void)printf("Logging in with home = \"/\".\n"); 346 } 347 348 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 349 350 if (pwd->pw_change || pwd->pw_expire) 351 (void)gettimeofday(&tp, (struct timezone *)NULL); 352 if (pwd->pw_change) 353 if (tp.tv_sec >= pwd->pw_change) { 354 (void)printf("Sorry -- your password has expired.\n"); 355 sleepexit(1); 356 } else if (pwd->pw_change - tp.tv_sec < 357 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 358 (void)printf("Warning: your password expires on %s", 359 ctime(&pwd->pw_change)); 360 if (pwd->pw_expire) 361 if (tp.tv_sec >= pwd->pw_expire) { 362 (void)printf("Sorry -- your account has expired.\n"); 363 sleepexit(1); 364 } else if (pwd->pw_expire - tp.tv_sec < 365 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 366 (void)printf("Warning: your account expires on %s", 367 ctime(&pwd->pw_expire)); 368 369 /* Nothing else left to fail -- really log in. */ 370 memset((void *)&utmp, 0, sizeof(utmp)); 371 (void)time(&utmp.ut_time); 372 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 373 if (hostname) 374 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 375 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 376 login(&utmp); 377 378 dolastlog(quietlog); 379 380 (void)chown(ttyn, pwd->pw_uid, 381 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 382 383 if (ttyaction(ttyn, "login", pwd->pw_name)) 384 (void)printf("Warning: ttyaction failed.\n"); 385 386 #if defined(KERBEROS) || defined(KERBEROS5) 387 /* Fork so that we can call kdestroy */ 388 if (krbtkfile_env) 389 dofork(); 390 #endif 391 (void)setgid(pwd->pw_gid); 392 393 initgroups(username, pwd->pw_gid); 394 395 if (*pwd->pw_shell == '\0') 396 pwd->pw_shell = _PATH_BSHELL; 397 398 /* Destroy environment unless user has requested its preservation. */ 399 if (!pflag) 400 environ = envinit; 401 (void)setenv("HOME", pwd->pw_dir, 1); 402 (void)setenv("SHELL", pwd->pw_shell, 1); 403 if (term[0] == '\0') 404 (void)strncpy(term, stypeof(tty), sizeof(term)); 405 (void)setenv("TERM", term, 0); 406 (void)setenv("LOGNAME", pwd->pw_name, 1); 407 (void)setenv("USER", pwd->pw_name, 1); 408 (void)setenv("PATH", _PATH_DEFPATH, 0); 409 #ifdef KERBEROS 410 if (krbtkfile_env) 411 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 412 #endif 413 #ifdef KERBEROS5 414 if (krbtkfile_env) 415 (void)setenv("KRB5CCNAME", krbtkfile_env, 1); 416 #endif 417 418 if (tty[sizeof("tty")-1] == 'd') 419 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 420 421 /* If fflag is on, assume caller/authenticator has logged root login. */ 422 if (rootlogin && fflag == 0) 423 if (hostname) 424 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 425 username, tty, hostname); 426 else 427 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 428 429 #if defined(KERBEROS) || defined(KERBEROS5) 430 if (!quietlog && notickets == 1) 431 (void)printf("Warning: no Kerberos tickets issued.\n"); 432 #endif 433 434 if (!quietlog) { 435 (void)printf("%s\n\t%s %s\n\n", 436 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", 437 "The Regents of the University of California. ", 438 "All rights reserved."); 439 motd(); 440 (void)snprintf(tbuf, 441 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 442 if (stat(tbuf, &st) == 0 && st.st_size != 0) 443 (void)printf("You have %smail.\n", 444 (st.st_mtime > st.st_atime) ? "new " : ""); 445 } 446 447 (void)signal(SIGALRM, SIG_DFL); 448 (void)signal(SIGQUIT, SIG_DFL); 449 (void)signal(SIGINT, SIG_DFL); 450 (void)signal(SIGTSTP, SIG_IGN); 451 452 tbuf[0] = '-'; 453 (void)strncpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? 454 p + 1 : pwd->pw_shell, sizeof(tbuf) - 2); 455 456 if (setlogin(pwd->pw_name) < 0) 457 syslog(LOG_ERR, "setlogin() failure: %m"); 458 459 /* Discard permissions last so can't get killed and drop core. */ 460 if (rootlogin) 461 (void) setuid(0); 462 else 463 (void) setuid(pwd->pw_uid); 464 465 execlp(pwd->pw_shell, tbuf, 0); 466 err(1, "%s", pwd->pw_shell); 467 } 468 469 int 470 pwcheck(user, p, salt, passwd) 471 char *user, *p, *salt, *passwd; 472 { 473 #ifdef SKEY 474 if (strcasecmp(p, "s/key") == 0) 475 if (skey_haskey(user)) 476 return 1; 477 else 478 return skey_authenticate(user); 479 #endif 480 return strcmp(crypt(p, salt), passwd); 481 } 482 483 #if defined(KERBEROS) || defined(KERBEROS5) 484 #define NBUFSIZ (MAXLOGNAME + 1 + 5) /* .root suffix */ 485 #else 486 #define NBUFSIZ (MAXLOGNAME + 1) 487 #endif 488 489 #if defined(KERBEROS) || defined(KERBEROS5) 490 /* 491 * This routine handles cleanup stuff, and the like. 492 * It exists only in the child process. 493 */ 494 #include <sys/wait.h> 495 void 496 dofork() 497 { 498 int child; 499 500 if (!(child = fork())) 501 return; /* Child process */ 502 503 /* Setup stuff? This would be things we could do in parallel with login */ 504 (void) chdir("/"); /* Let's not keep the fs busy... */ 505 506 /* If we're the parent, watch the child until it dies */ 507 while (wait(0) != child) 508 ; 509 510 /* Cleanup stuff */ 511 /* Run kdestroy to destroy tickets */ 512 kdestroy(); 513 514 /* Leave */ 515 exit(0); 516 } 517 #endif 518 519 void 520 getloginname() 521 { 522 int ch; 523 char *p; 524 static char nbuf[NBUFSIZ]; 525 526 for (;;) { 527 (void)printf("login: "); 528 for (p = nbuf; (ch = getchar()) != '\n'; ) { 529 if (ch == EOF) { 530 badlogin(username); 531 exit(0); 532 } 533 if (p < nbuf + (NBUFSIZ - 1)) 534 *p++ = ch; 535 } 536 if (p > nbuf) 537 if (nbuf[0] == '-') 538 (void)fprintf(stderr, 539 "login names may not start with '-'.\n"); 540 else { 541 *p = '\0'; 542 username = nbuf; 543 break; 544 } 545 } 546 } 547 548 int 549 rootterm(ttyn) 550 char *ttyn; 551 { 552 struct ttyent *t; 553 554 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 555 } 556 557 jmp_buf motdinterrupt; 558 559 void 560 motd() 561 { 562 int fd, nchars; 563 sig_t oldint; 564 char tbuf[8192]; 565 566 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 567 return; 568 oldint = signal(SIGINT, sigint); 569 if (setjmp(motdinterrupt) == 0) 570 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 571 (void)write(fileno(stdout), tbuf, nchars); 572 (void)signal(SIGINT, oldint); 573 (void)close(fd); 574 } 575 576 /* ARGSUSED */ 577 void 578 sigint(signo) 579 int signo; 580 { 581 longjmp(motdinterrupt, 1); 582 } 583 584 /* ARGSUSED */ 585 void 586 timedout(signo) 587 int signo; 588 { 589 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 590 exit(0); 591 } 592 593 void 594 checknologin() 595 { 596 int fd, nchars; 597 char tbuf[8192]; 598 599 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 600 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 601 (void)write(fileno(stdout), tbuf, nchars); 602 sleepexit(0); 603 } 604 } 605 606 void 607 dolastlog(quiet) 608 int quiet; 609 { 610 struct lastlog ll; 611 int fd; 612 613 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 614 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 615 if (!quiet) { 616 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 617 ll.ll_time != 0) { 618 (void)printf("Last login: %.*s ", 619 24-5, (char *)ctime(&ll.ll_time)); 620 if (*ll.ll_host != '\0') 621 (void)printf("from %.*s\n", 622 (int)sizeof(ll.ll_host), 623 ll.ll_host); 624 else 625 (void)printf("on %.*s\n", 626 (int)sizeof(ll.ll_line), 627 ll.ll_line); 628 } 629 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 630 } 631 memset((void *)&ll, 0, sizeof(ll)); 632 (void)time(&ll.ll_time); 633 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 634 if (hostname) 635 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 636 (void)write(fd, (char *)&ll, sizeof(ll)); 637 (void)close(fd); 638 } 639 } 640 641 void 642 badlogin(name) 643 char *name; 644 { 645 if (failures == 0) 646 return; 647 if (hostname) { 648 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 649 failures, failures > 1 ? "S" : "", hostname); 650 syslog(LOG_AUTHPRIV|LOG_NOTICE, 651 "%d LOGIN FAILURE%s FROM %s, %s", 652 failures, failures > 1 ? "S" : "", hostname, name); 653 } else { 654 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 655 failures, failures > 1 ? "S" : "", tty); 656 syslog(LOG_AUTHPRIV|LOG_NOTICE, 657 "%d LOGIN FAILURE%s ON %s, %s", 658 failures, failures > 1 ? "S" : "", tty, name); 659 } 660 } 661 662 #undef UNKNOWN 663 #define UNKNOWN "su" 664 665 char * 666 stypeof(ttyid) 667 char *ttyid; 668 { 669 struct ttyent *t; 670 671 return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 672 } 673 674 void 675 sleepexit(eval) 676 int eval; 677 { 678 (void)sleep(5); 679 exit(eval); 680 } 681
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