login.c revision 1.7
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 1.7 1993/12/02 04:24:05 mycroft 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 #ifdef KERBEROS 83 int klogin __P((struct passwd *, char *, char *, char *)); 84 #endif 85 86 #define TTYGRPNAME "tty" /* name of group to own ttys */ 87 88 /* 89 * This bounds the time given to login. Not a define so it can 90 * be patched on machines where it's too small. 91 */ 92 int timeout = 300; 93 94 #ifdef KERBEROS 95 int notickets = 1; 96 char *instance; 97 char *krbtkfile_env; 98 int authok; 99 #endif 100 101 struct passwd *pwd; 102 int failures; 103 char term[64], *envinit[1], *hostname, *username, *tty; 104 105 int 106 main(argc, argv) 107 int argc; 108 char *argv[]; 109 { 110 extern char **environ; 111 register int ch; 112 register char *p; 113 struct group *gr; 114 struct stat st; 115 struct timeval tp; 116 struct utmp utmp; 117 int ask, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval, uid; 118 char *domain, *salt, *ttyn; 119 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 120 char localhost[MAXHOSTNAMELEN]; 121 122 (void)signal(SIGALRM, timedout); 123 (void)alarm((u_int)timeout); 124 (void)signal(SIGQUIT, SIG_IGN); 125 (void)signal(SIGINT, SIG_IGN); 126 (void)setpriority(PRIO_PROCESS, 0, 0); 127 128 openlog("login", LOG_ODELAY, LOG_AUTH); 129 130 /* 131 * -p is used by getty to tell login not to destroy the environment 132 * -f is used to skip a second login authentication 133 * -h is used by other servers to pass the name of the remote 134 * host to login so that it may be placed in utmp and wtmp 135 */ 136 domain = NULL; 137 if (gethostname(localhost, sizeof(localhost)) < 0) 138 syslog(LOG_ERR, "couldn't get local hostname: %m"); 139 else 140 domain = index(localhost, '.'); 141 142 fflag = hflag = pflag = 0; 143 uid = getuid(); 144 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 145 switch (ch) { 146 case 'f': 147 fflag = 1; 148 break; 149 case 'h': 150 if (uid) { 151 (void)fprintf(stderr, 152 "login: -h option: %s\n", strerror(EPERM)); 153 exit(1); 154 } 155 hflag = 1; 156 if (domain && (p = index(optarg, '.')) && 157 strcasecmp(p, domain) == 0) 158 *p = 0; 159 hostname = optarg; 160 break; 161 case 'p': 162 pflag = 1; 163 break; 164 case '?': 165 default: 166 if (!uid) 167 syslog(LOG_ERR, "invalid flag %c", ch); 168 (void)fprintf(stderr, 169 "usage: login [-fp] [-h hostname] [username]\n"); 170 exit(1); 171 } 172 argc -= optind; 173 argv += optind; 174 175 if (*argv) { 176 username = *argv; 177 ask = 0; 178 } else 179 ask = 1; 180 181 for (cnt = getdtablesize(); cnt > 2; cnt--) 182 (void)close(cnt); 183 184 ttyn = ttyname(STDIN_FILENO); 185 if (ttyn == NULL || *ttyn == '\0') { 186 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 187 ttyn = tname; 188 } 189 if (tty = rindex(ttyn, '/')) 190 ++tty; 191 else 192 tty = ttyn; 193 194 for (cnt = 0;; ask = 1) { 195 if (ask) { 196 fflag = 0; 197 getloginname(); 198 } 199 rootlogin = 0; 200 #ifdef KERBEROS 201 if ((instance = index(username, '.')) != NULL) { 202 if (strncmp(instance, ".root", 5) == 0) 203 rootlogin = 1; 204 *instance++ = '\0'; 205 } else 206 instance = ""; 207 #endif 208 if (strlen(username) > UT_NAMESIZE) 209 username[UT_NAMESIZE] = '\0'; 210 211 /* 212 * Note if trying multiple user names; log failures for 213 * previous user name, but don't bother logging one failure 214 * for nonexistent name (mistyped username). 215 */ 216 if (failures && strcmp(tbuf, username)) { 217 if (failures > (pwd ? 0 : 1)) 218 badlogin(tbuf); 219 failures = 0; 220 } 221 (void)strcpy(tbuf, username); 222 223 if (pwd = getpwnam(username)) 224 salt = pwd->pw_passwd; 225 else 226 salt = "xx"; 227 228 /* 229 * if we have a valid account name, and it doesn't have a 230 * password, or the -f option was specified and the caller 231 * is root or the caller isn't changing their uid, don't 232 * authenticate. 233 */ 234 if (pwd) { 235 if (pwd->pw_uid == 0) 236 rootlogin = 1; 237 238 if (fflag && (uid == 0 || uid == pwd->pw_uid))) { 239 /* already authenticated */ 240 break; 241 } else if (pwd->pw_passwd[0] == '\0') { 242 /* pretend password okay */ 243 rval = 0; 244 goto ttycheck; 245 } 246 } 247 248 fflag = 0; 249 250 (void)setpriority(PRIO_PROCESS, 0, -4); 251 252 p = getpass("Password:"); 253 254 if (pwd) { 255 #ifdef KERBEROS 256 rval = klogin(pwd, instance, localhost, p); 257 if (rval == 0) 258 authok = 1; 259 else if (rval == 1) 260 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 261 #else 262 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 263 #endif 264 } 265 bzero(p, strlen(p)); 266 267 (void)setpriority(PRIO_PROCESS, 0, 0); 268 269 ttycheck: 270 /* 271 * If trying to log in as root without Kerberos, 272 * but with insecure terminal, refuse the login attempt. 273 */ 274 #ifdef KERBEROS 275 if (authok == 0) 276 #endif 277 if (pwd && !rval && rootlogin && !rootterm(tty)) { 278 (void)fprintf(stderr, 279 "%s login refused on this terminal.\n", 280 pwd->pw_name); 281 if (hostname) 282 syslog(LOG_NOTICE, 283 "LOGIN %s REFUSED FROM %s ON TTY %s", 284 pwd->pw_name, hostname, tty); 285 else 286 syslog(LOG_NOTICE, 287 "LOGIN %s REFUSED ON TTY %s", 288 pwd->pw_name, tty); 289 continue; 290 } 291 292 if (pwd && !rval) 293 break; 294 295 (void)printf("Login incorrect\n"); 296 failures++; 297 /* we allow 10 tries, but after 3 we start backing off */ 298 if (++cnt > 3) { 299 if (cnt >= 10) { 300 badlogin(username); 301 sleepexit(1); 302 } 303 sleep((u_int)((cnt - 3) * 5)); 304 } 305 } 306 307 /* committed to login -- turn off timeout */ 308 (void)alarm((u_int)0); 309 310 endpwent(); 311 312 /* if user not super-user, check for disabled logins */ 313 if (!rootlogin) 314 checknologin(); 315 316 if (chdir(pwd->pw_dir) < 0) { 317 (void)printf("No home directory %s!\n", pwd->pw_dir); 318 if (chdir("/")) 319 exit(0); 320 pwd->pw_dir = "/"; 321 (void)printf("Logging in with home = \"/\".\n"); 322 } 323 324 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 325 326 if (pwd->pw_change || pwd->pw_expire) 327 (void)gettimeofday(&tp, (struct timezone *)NULL); 328 if (pwd->pw_change) 329 if (tp.tv_sec >= pwd->pw_change) { 330 (void)printf("Sorry -- your password has expired.\n"); 331 sleepexit(1); 332 } else if (pwd->pw_change - tp.tv_sec < 333 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 334 (void)printf("Warning: your password expires on %s", 335 ctime(&pwd->pw_change)); 336 if (pwd->pw_expire) 337 if (tp.tv_sec >= pwd->pw_expire) { 338 (void)printf("Sorry -- your account has expired.\n"); 339 sleepexit(1); 340 } else if (pwd->pw_expire - tp.tv_sec < 341 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 342 (void)printf("Warning: your account expires on %s", 343 ctime(&pwd->pw_expire)); 344 345 /* Nothing else left to fail -- really log in. */ 346 bzero((void *)&utmp, sizeof(utmp)); 347 (void)time(&utmp.ut_time); 348 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 349 if (hostname) 350 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 351 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 352 login(&utmp); 353 354 dolastlog(quietlog); 355 356 (void)chown(ttyn, pwd->pw_uid, 357 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 358 (void)setgid(pwd->pw_gid); 359 360 initgroups(username, pwd->pw_gid); 361 362 if (*pwd->pw_shell == '\0') 363 pwd->pw_shell = _PATH_BSHELL; 364 365 /* Destroy environment unless user has requested its preservation. */ 366 if (!pflag) 367 environ = envinit; 368 (void)setenv("HOME", pwd->pw_dir, 1); 369 (void)setenv("SHELL", pwd->pw_shell, 1); 370 if (term[0] == '\0') 371 (void)strncpy(term, stypeof(tty), sizeof(term)); 372 (void)setenv("TERM", term, 0); 373 (void)setenv("LOGNAME", pwd->pw_name, 1); 374 (void)setenv("USER", pwd->pw_name, 1); 375 (void)setenv("PATH", _PATH_DEFPATH, 0); 376 #ifdef KERBEROS 377 if (krbtkfile_env) 378 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 379 #endif 380 381 if (tty[sizeof("tty")-1] == 'd') 382 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 383 384 /* If fflag is on, assume caller/authenticator has logged root login. */ 385 if (rootlogin && fflag == 0) 386 if (hostname) 387 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 388 username, tty, hostname); 389 else 390 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 391 392 #ifdef KERBEROS 393 if (!quietlog && notickets == 1) 394 (void)printf("Warning: no Kerberos tickets issued.\n"); 395 #endif 396 397 if (!quietlog) { 398 (void)printf( 399 "Copyright (c) 1980,1983,1986,1988,1990,1991 The Regents of the University\n%s", 400 "of California. All rights reserved.\n\n"); 401 motd(); 402 (void)snprintf(tbuf, 403 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 404 if (stat(tbuf, &st) == 0 && st.st_size != 0) 405 (void)printf("You have %smail.\n", 406 (st.st_mtime > st.st_atime) ? "new " : ""); 407 } 408 409 (void)signal(SIGALRM, SIG_DFL); 410 (void)signal(SIGQUIT, SIG_DFL); 411 (void)signal(SIGINT, SIG_DFL); 412 (void)signal(SIGTSTP, SIG_IGN); 413 414 tbuf[0] = '-'; 415 (void)strcpy(tbuf + 1, (p = rindex(pwd->pw_shell, '/')) ? 416 p + 1 : pwd->pw_shell); 417 418 if (setlogin(pwd->pw_name) < 0) 419 syslog(LOG_ERR, "setlogin() failure: %m"); 420 421 /* Discard permissions last so can't get killed and drop core. */ 422 if (rootlogin) 423 (void) setuid(0); 424 else 425 (void) setuid(pwd->pw_uid); 426 427 execlp(pwd->pw_shell, tbuf, 0); 428 (void)fprintf(stderr, "%s: %s\n", pwd->pw_shell, strerror(errno)); 429 exit(1); 430 } 431 432 #ifdef KERBEROS 433 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 434 #else 435 #define NBUFSIZ (UT_NAMESIZE + 1) 436 #endif 437 438 void 439 getloginname() 440 { 441 register int ch; 442 register char *p; 443 static char nbuf[NBUFSIZ]; 444 445 for (;;) { 446 (void)printf("login: "); 447 for (p = nbuf; (ch = getchar()) != '\n'; ) { 448 if (ch == EOF) { 449 badlogin(username); 450 exit(0); 451 } 452 if (p < nbuf + (NBUFSIZ - 1)) 453 *p++ = ch; 454 } 455 if (p > nbuf) 456 if (nbuf[0] == '-') 457 (void)fprintf(stderr, 458 "login names may not start with '-'.\n"); 459 else { 460 *p = '\0'; 461 username = nbuf; 462 break; 463 } 464 } 465 } 466 467 int 468 rootterm(ttyn) 469 char *ttyn; 470 { 471 struct ttyent *t; 472 473 return((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 474 } 475 476 jmp_buf motdinterrupt; 477 478 void 479 motd() 480 { 481 register int fd, nchars; 482 sig_t oldint; 483 char tbuf[8192]; 484 485 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 486 return; 487 oldint = signal(SIGINT, sigint); 488 if (setjmp(motdinterrupt) == 0) 489 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 490 (void)write(fileno(stdout), tbuf, nchars); 491 (void)signal(SIGINT, oldint); 492 (void)close(fd); 493 } 494 495 /* ARGSUSED */ 496 void 497 sigint(signo) 498 int signo; 499 { 500 longjmp(motdinterrupt, 1); 501 } 502 503 /* ARGSUSED */ 504 void 505 timedout(signo) 506 int signo; 507 { 508 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 509 exit(0); 510 } 511 512 void 513 checknologin() 514 { 515 register int fd, nchars; 516 char tbuf[8192]; 517 518 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 519 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 520 (void)write(fileno(stdout), tbuf, nchars); 521 sleepexit(0); 522 } 523 } 524 525 void 526 dolastlog(quiet) 527 int quiet; 528 { 529 struct lastlog ll; 530 int fd; 531 532 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 533 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 534 if (!quiet) { 535 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 536 ll.ll_time != 0) { 537 (void)printf("Last login: %.*s ", 538 24-5, (char *)ctime(&ll.ll_time)); 539 if (*ll.ll_host != '\0') 540 (void)printf("from %.*s\n", 541 (int)sizeof(ll.ll_host), 542 ll.ll_host); 543 else 544 (void)printf("on %.*s\n", 545 (int)sizeof(ll.ll_line), 546 ll.ll_line); 547 } 548 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 549 } 550 bzero((void *)&ll, sizeof(ll)); 551 (void)time(&ll.ll_time); 552 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 553 if (hostname) 554 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 555 (void)write(fd, (char *)&ll, sizeof(ll)); 556 (void)close(fd); 557 } 558 } 559 560 void 561 badlogin(name) 562 char *name; 563 { 564 if (failures == 0) 565 return; 566 if (hostname) { 567 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 568 failures, failures > 1 ? "S" : "", hostname); 569 syslog(LOG_AUTHPRIV|LOG_NOTICE, 570 "%d LOGIN FAILURE%s FROM %s, %s", 571 failures, failures > 1 ? "S" : "", hostname, name); 572 } else { 573 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 574 failures, failures > 1 ? "S" : "", tty); 575 syslog(LOG_AUTHPRIV|LOG_NOTICE, 576 "%d LOGIN FAILURE%s ON %s, %s", 577 failures, failures > 1 ? "S" : "", tty, name); 578 } 579 } 580 581 #undef UNKNOWN 582 #define UNKNOWN "su" 583 584 char * 585 stypeof(ttyid) 586 char *ttyid; 587 { 588 struct ttyent *t; 589 590 return(ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 591 } 592 593 void 594 sleepexit(eval) 595 int eval; 596 { 597 (void)sleep((u_int)5); 598 exit(eval); 599 } 600
Indexes created Wed Oct 01 07:09:59 GMT 2025