login.c revision 1.9
1 /*- 2 * Copyright (c) 1980, 1987, 1988, 1991 The Regents of the University 3 * 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 char copyright[] = 36 "@(#) Copyright (c) 1980, 1987, 1988, 1991 The Regents of the University of California.\n\ 37 All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 /*static char sccsid[] = "from: @(#)login.c 5.78 (Berkeley) 6/29/92";*/ 42 static char rcsid[] = "$Id: login.c,v 1.9 1994/05/24 06:51:03 deraadt Exp $"; 43 #endif /* not lint */ 44 45 /* 46 * login [ name ] 47 * login -h hostname (for telnetd, etc.) 48 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 49 */ 50 51 #include <sys/param.h> 52 #include <sys/stat.h> 53 #include <sys/time.h> 54 #include <sys/resource.h> 55 #include <sys/file.h> 56 57 #include <signal.h> 58 #include <ttyent.h> 59 #include <syslog.h> 60 #include <setjmp.h> 61 #include <tzfile.h> 62 #include <utmp.h> 63 #include <errno.h> 64 #include <grp.h> 65 #include <pwd.h> 66 #include <unistd.h> 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include "pathnames.h" 71 72 void badlogin __P((char *)); 73 void checknologin __P((void)); 74 void dolastlog __P((int)); 75 void getloginname __P((void)); 76 void motd __P((void)); 77 int rootterm __P((char *)); 78 void sigint __P((int)); 79 void sleepexit __P((int)); 80 char *stypeof __P((char *)); 81 void timedout __P((int)); 82 int pwcheck __P((char *, char *, char *, char *)); 83 #ifdef KERBEROS 84 int klogin __P((struct passwd *, char *, char *, char *)); 85 #endif 86 87 #define TTYGRPNAME "tty" /* name of group to own ttys */ 88 89 /* 90 * This bounds the time given to login. Not a define so it can 91 * be patched on machines where it's too small. 92 */ 93 int timeout = 300; 94 95 #ifdef KERBEROS 96 int notickets = 1; 97 char *instance; 98 char *krbtkfile_env; 99 int authok; 100 #endif 101 102 struct passwd *pwd; 103 int failures; 104 char term[64], *envinit[1], *hostname, *username, *tty; 105 106 int 107 main(argc, argv) 108 int argc; 109 char *argv[]; 110 { 111 extern char **environ; 112 register int ch; 113 register char *p; 114 struct group *gr; 115 struct stat st; 116 struct timeval tp; 117 struct utmp utmp; 118 int ask, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval, uid; 119 char *domain, *salt, *ttyn; 120 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 121 char localhost[MAXHOSTNAMELEN]; 122 123 (void)signal(SIGALRM, timedout); 124 (void)alarm((u_int)timeout); 125 (void)signal(SIGQUIT, SIG_IGN); 126 (void)signal(SIGINT, SIG_IGN); 127 (void)setpriority(PRIO_PROCESS, 0, 0); 128 129 openlog("login", LOG_ODELAY, LOG_AUTH); 130 131 /* 132 * -p is used by getty to tell login not to destroy the environment 133 * -f is used to skip a second login authentication 134 * -h is used by other servers to pass the name of the remote 135 * host to login so that it may be placed in utmp and wtmp 136 */ 137 domain = NULL; 138 if (gethostname(localhost, sizeof(localhost)) < 0) 139 syslog(LOG_ERR, "couldn't get local hostname: %m"); 140 else 141 domain = index(localhost, '.'); 142 143 fflag = hflag = pflag = 0; 144 uid = getuid(); 145 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 146 switch (ch) { 147 case 'f': 148 fflag = 1; 149 break; 150 case 'h': 151 if (uid) { 152 (void)fprintf(stderr, 153 "login: -h option: %s\n", strerror(EPERM)); 154 exit(1); 155 } 156 hflag = 1; 157 if (domain && (p = index(optarg, '.')) && 158 strcasecmp(p, domain) == 0) 159 *p = 0; 160 hostname = optarg; 161 break; 162 case 'p': 163 pflag = 1; 164 break; 165 case '?': 166 default: 167 if (!uid) 168 syslog(LOG_ERR, "invalid flag %c", ch); 169 (void)fprintf(stderr, 170 "usage: login [-fp] [-h hostname] [username]\n"); 171 exit(1); 172 } 173 argc -= optind; 174 argv += optind; 175 176 if (*argv) { 177 username = *argv; 178 ask = 0; 179 } else 180 ask = 1; 181 182 for (cnt = getdtablesize(); cnt > 2; cnt--) 183 (void)close(cnt); 184 185 ttyn = ttyname(STDIN_FILENO); 186 if (ttyn == NULL || *ttyn == '\0') { 187 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 188 ttyn = tname; 189 } 190 if (tty = rindex(ttyn, '/')) 191 ++tty; 192 else 193 tty = ttyn; 194 195 for (cnt = 0;; ask = 1) { 196 if (ask) { 197 fflag = 0; 198 getloginname(); 199 } 200 rootlogin = 0; 201 #ifdef KERBEROS 202 if ((instance = index(username, '.')) != NULL) { 203 if (strncmp(instance, ".root", 5) == 0) 204 rootlogin = 1; 205 *instance++ = '\0'; 206 } else 207 instance = ""; 208 #endif 209 if (strlen(username) > UT_NAMESIZE) 210 username[UT_NAMESIZE] = '\0'; 211 212 /* 213 * Note if trying multiple user names; log failures for 214 * previous user name, but don't bother logging one failure 215 * for nonexistent name (mistyped username). 216 */ 217 if (failures && strcmp(tbuf, username)) { 218 if (failures > (pwd ? 0 : 1)) 219 badlogin(tbuf); 220 failures = 0; 221 } 222 (void)strcpy(tbuf, username); 223 224 if (pwd = getpwnam(username)) 225 salt = pwd->pw_passwd; 226 else 227 salt = "xx"; 228 229 /* 230 * if we have a valid account name, and it doesn't have a 231 * password, or the -f option was specified and the caller 232 * is root or the caller isn't changing their uid, don't 233 * authenticate. 234 */ 235 if (pwd) { 236 if (pwd->pw_uid == 0) 237 rootlogin = 1; 238 239 if (fflag && (uid == 0 || uid == pwd->pw_uid)) { 240 /* already authenticated */ 241 break; 242 } else if (pwd->pw_passwd[0] == '\0') { 243 /* pretend password okay */ 244 rval = 0; 245 goto ttycheck; 246 } 247 } 248 249 fflag = 0; 250 251 (void)setpriority(PRIO_PROCESS, 0, -4); 252 253 p = getpass("Password:"); 254 255 if (pwd) { 256 #ifdef KERBEROS 257 rval = klogin(pwd, instance, localhost, p); 258 if (rval == 0) 259 authok = 1; 260 else if (rval == 1) 261 rval = pwcheck(username, p, salt, pwd->pw_passwd); 262 #else 263 rval = pwcheck(username, p, salt, pwd->pw_passwd); 264 #endif 265 } 266 bzero(p, strlen(p)); 267 268 (void)setpriority(PRIO_PROCESS, 0, 0); 269 270 ttycheck: 271 /* 272 * If trying to log in as root without Kerberos, 273 * but with insecure terminal, refuse the login attempt. 274 */ 275 #ifdef KERBEROS 276 if (authok == 0) 277 #endif 278 if (pwd && !rval && rootlogin && !rootterm(tty)) { 279 (void)fprintf(stderr, 280 "%s login refused on this terminal.\n", 281 pwd->pw_name); 282 if (hostname) 283 syslog(LOG_NOTICE, 284 "LOGIN %s REFUSED FROM %s ON TTY %s", 285 pwd->pw_name, hostname, tty); 286 else 287 syslog(LOG_NOTICE, 288 "LOGIN %s REFUSED ON TTY %s", 289 pwd->pw_name, tty); 290 continue; 291 } 292 293 if (pwd && !rval) 294 break; 295 296 (void)printf("Login incorrect\n"); 297 failures++; 298 /* we allow 10 tries, but after 3 we start backing off */ 299 if (++cnt > 3) { 300 if (cnt >= 10) { 301 badlogin(username); 302 sleepexit(1); 303 } 304 sleep((u_int)((cnt - 3) * 5)); 305 } 306 } 307 308 /* committed to login -- turn off timeout */ 309 (void)alarm((u_int)0); 310 311 endpwent(); 312 313 /* if user not super-user, check for disabled logins */ 314 if (!rootlogin) 315 checknologin(); 316 317 if (chdir(pwd->pw_dir) < 0) { 318 (void)printf("No home directory %s!\n", pwd->pw_dir); 319 if (chdir("/")) 320 exit(0); 321 pwd->pw_dir = "/"; 322 (void)printf("Logging in with home = \"/\".\n"); 323 } 324 325 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 326 327 if (pwd->pw_change || pwd->pw_expire) 328 (void)gettimeofday(&tp, (struct timezone *)NULL); 329 if (pwd->pw_change) 330 if (tp.tv_sec >= pwd->pw_change) { 331 (void)printf("Sorry -- your password has expired.\n"); 332 sleepexit(1); 333 } else if (pwd->pw_change - tp.tv_sec < 334 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 335 (void)printf("Warning: your password expires on %s", 336 ctime(&pwd->pw_change)); 337 if (pwd->pw_expire) 338 if (tp.tv_sec >= pwd->pw_expire) { 339 (void)printf("Sorry -- your account has expired.\n"); 340 sleepexit(1); 341 } else if (pwd->pw_expire - tp.tv_sec < 342 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 343 (void)printf("Warning: your account expires on %s", 344 ctime(&pwd->pw_expire)); 345 346 /* Nothing else left to fail -- really log in. */ 347 bzero((void *)&utmp, sizeof(utmp)); 348 (void)time(&utmp.ut_time); 349 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 350 if (hostname) 351 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 352 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 353 login(&utmp); 354 355 dolastlog(quietlog); 356 357 (void)chown(ttyn, pwd->pw_uid, 358 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 359 (void)setgid(pwd->pw_gid); 360 361 initgroups(username, pwd->pw_gid); 362 363 if (*pwd->pw_shell == '\0') 364 pwd->pw_shell = _PATH_BSHELL; 365 366 /* Destroy environment unless user has requested its preservation. */ 367 if (!pflag) 368 environ = envinit; 369 (void)setenv("HOME", pwd->pw_dir, 1); 370 (void)setenv("SHELL", pwd->pw_shell, 1); 371 if (term[0] == '\0') 372 (void)strncpy(term, stypeof(tty), sizeof(term)); 373 (void)setenv("TERM", term, 0); 374 (void)setenv("LOGNAME", pwd->pw_name, 1); 375 (void)setenv("USER", pwd->pw_name, 1); 376 (void)setenv("PATH", _PATH_DEFPATH, 0); 377 #ifdef KERBEROS 378 if (krbtkfile_env) 379 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 380 #endif 381 382 if (tty[sizeof("tty")-1] == 'd') 383 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 384 385 /* If fflag is on, assume caller/authenticator has logged root login. */ 386 if (rootlogin && fflag == 0) 387 if (hostname) 388 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 389 username, tty, hostname); 390 else 391 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 392 393 #ifdef KERBEROS 394 if (!quietlog && notickets == 1) 395 (void)printf("Warning: no Kerberos tickets issued.\n"); 396 #endif 397 398 if (!quietlog) { 399 (void)printf( 400 "Copyright (c) 1980,1983,1986,1988,1990,1991 The Regents of the University\n%s", 401 "of California. All rights reserved.\n\n"); 402 motd(); 403 (void)snprintf(tbuf, 404 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 405 if (stat(tbuf, &st) == 0 && st.st_size != 0) 406 (void)printf("You have %smail.\n", 407 (st.st_mtime > st.st_atime) ? "new " : ""); 408 } 409 410 (void)signal(SIGALRM, SIG_DFL); 411 (void)signal(SIGQUIT, SIG_DFL); 412 (void)signal(SIGINT, SIG_DFL); 413 (void)signal(SIGTSTP, SIG_IGN); 414 415 tbuf[0] = '-'; 416 (void)strcpy(tbuf + 1, (p = rindex(pwd->pw_shell, '/')) ? 417 p + 1 : pwd->pw_shell); 418 419 if (setlogin(pwd->pw_name) < 0) 420 syslog(LOG_ERR, "setlogin() failure: %m"); 421 422 /* Discard permissions last so can't get killed and drop core. */ 423 if (rootlogin) 424 (void) setuid(0); 425 else 426 (void) setuid(pwd->pw_uid); 427 428 execlp(pwd->pw_shell, tbuf, 0); 429 (void)fprintf(stderr, "%s: %s\n", pwd->pw_shell, strerror(errno)); 430 exit(1); 431 } 432 433 int 434 pwcheck(user, p, salt, passwd) 435 char *user, *p, *salt, *passwd; 436 { 437 #ifdef SKEY 438 if (strcasecmp(p, "s/key") == 0) { 439 if (skey_haskey(user)) { 440 fprintf(stderr, "You have no s/key. "); 441 return 1; 442 } else { 443 return skey_authenticate(user); 444 } 445 } 446 #endif 447 return strcmp(crypt(p, salt), passwd); 448 } 449 450 #ifdef KERBEROS 451 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 452 #else 453 #define NBUFSIZ (UT_NAMESIZE + 1) 454 #endif 455 456 void 457 getloginname() 458 { 459 register int ch; 460 register char *p; 461 static char nbuf[NBUFSIZ]; 462 463 for (;;) { 464 (void)printf("login: "); 465 for (p = nbuf; (ch = getchar()) != '\n'; ) { 466 if (ch == EOF) { 467 badlogin(username); 468 exit(0); 469 } 470 if (p < nbuf + (NBUFSIZ - 1)) 471 *p++ = ch; 472 } 473 if (p > nbuf) 474 if (nbuf[0] == '-') 475 (void)fprintf(stderr, 476 "login names may not start with '-'.\n"); 477 else { 478 *p = '\0'; 479 username = nbuf; 480 break; 481 } 482 } 483 } 484 485 int 486 rootterm(ttyn) 487 char *ttyn; 488 { 489 struct ttyent *t; 490 491 return((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 492 } 493 494 jmp_buf motdinterrupt; 495 496 void 497 motd() 498 { 499 register int fd, nchars; 500 sig_t oldint; 501 char tbuf[8192]; 502 503 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 504 return; 505 oldint = signal(SIGINT, sigint); 506 if (setjmp(motdinterrupt) == 0) 507 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 508 (void)write(fileno(stdout), tbuf, nchars); 509 (void)signal(SIGINT, oldint); 510 (void)close(fd); 511 } 512 513 /* ARGSUSED */ 514 void 515 sigint(signo) 516 int signo; 517 { 518 longjmp(motdinterrupt, 1); 519 } 520 521 /* ARGSUSED */ 522 void 523 timedout(signo) 524 int signo; 525 { 526 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 527 exit(0); 528 } 529 530 void 531 checknologin() 532 { 533 register int fd, nchars; 534 char tbuf[8192]; 535 536 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 537 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 538 (void)write(fileno(stdout), tbuf, nchars); 539 sleepexit(0); 540 } 541 } 542 543 void 544 dolastlog(quiet) 545 int quiet; 546 { 547 struct lastlog ll; 548 int fd; 549 550 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 551 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 552 if (!quiet) { 553 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 554 ll.ll_time != 0) { 555 (void)printf("Last login: %.*s ", 556 24-5, (char *)ctime(&ll.ll_time)); 557 if (*ll.ll_host != '\0') 558 (void)printf("from %.*s\n", 559 (int)sizeof(ll.ll_host), 560 ll.ll_host); 561 else 562 (void)printf("on %.*s\n", 563 (int)sizeof(ll.ll_line), 564 ll.ll_line); 565 } 566 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 567 } 568 bzero((void *)&ll, sizeof(ll)); 569 (void)time(&ll.ll_time); 570 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 571 if (hostname) 572 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 573 (void)write(fd, (char *)&ll, sizeof(ll)); 574 (void)close(fd); 575 } 576 } 577 578 void 579 badlogin(name) 580 char *name; 581 { 582 if (failures == 0) 583 return; 584 if (hostname) { 585 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 586 failures, failures > 1 ? "S" : "", hostname); 587 syslog(LOG_AUTHPRIV|LOG_NOTICE, 588 "%d LOGIN FAILURE%s FROM %s, %s", 589 failures, failures > 1 ? "S" : "", hostname, name); 590 } else { 591 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 592 failures, failures > 1 ? "S" : "", tty); 593 syslog(LOG_AUTHPRIV|LOG_NOTICE, 594 "%d LOGIN FAILURE%s ON %s, %s", 595 failures, failures > 1 ? "S" : "", tty, name); 596 } 597 } 598 599 #undef UNKNOWN 600 #define UNKNOWN "su" 601 602 char * 603 stypeof(ttyid) 604 char *ttyid; 605 { 606 struct ttyent *t; 607 608 return(ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 609 } 610 611 void 612 sleepexit(eval) 613 int eval; 614 { 615 (void)sleep((u_int)5); 616 exit(eval); 617 } 618
Indexes created Wed Oct 01 13:09:50 GMT 2025