login.c revision 1.1.1.2
1 /*- 2 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 3 * The Regents of the University 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 static char copyright[] = 36 "@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\ 37 The Regents of the University of California. All rights reserved.\n"; 38 #endif /* not lint */ 39 40 #ifndef lint 41 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; 42 #endif /* not lint */ 43 44 /* 45 * login [ name ] 46 * login -h hostname (for telnetd, etc.) 47 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 48 */ 49 50 #include <sys/param.h> 51 #include <sys/stat.h> 52 #include <sys/time.h> 53 #include <sys/resource.h> 54 #include <sys/file.h> 55 56 #include <err.h> 57 #include <errno.h> 58 #include <grp.h> 59 #include <pwd.h> 60 #include <setjmp.h> 61 #include <signal.h> 62 #include <stdio.h> 63 #include <stdlib.h> 64 #include <string.h> 65 #include <syslog.h> 66 #include <ttyent.h> 67 #include <tzfile.h> 68 #include <unistd.h> 69 #include <utmp.h> 70 71 #include "pathnames.h" 72 73 void badlogin __P((char *)); 74 void checknologin __P((void)); 75 void dolastlog __P((int)); 76 void getloginname __P((void)); 77 void motd __P((void)); 78 int rootterm __P((char *)); 79 void sigint __P((int)); 80 void sleepexit __P((int)); 81 char *stypeof __P((char *)); 82 void timedout __P((int)); 83 #ifdef KERBEROS 84 int klogin __P((struct passwd *, char *, char *, char *)); 85 #endif 86 87 extern void login __P((struct utmp *)); 88 89 #define TTYGRPNAME "tty" /* name of group to own ttys */ 90 91 /* 92 * This bounds the time given to login. Not a define so it can 93 * be patched on machines where it's too small. 94 */ 95 u_int timeout = 300; 96 97 #ifdef KERBEROS 98 int notickets = 1; 99 char *instance; 100 char *krbtkfile_env; 101 int authok; 102 #endif 103 104 struct passwd *pwd; 105 int failures; 106 char term[64], *envinit[1], *hostname, *username, *tty; 107 108 int 109 main(argc, argv) 110 int argc; 111 char *argv[]; 112 { 113 extern char **environ; 114 struct group *gr; 115 struct stat st; 116 struct timeval tp; 117 struct utmp utmp; 118 int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval; 119 uid_t uid; 120 char *domain, *p, *salt, *ttyn; 121 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 122 char localhost[MAXHOSTNAMELEN]; 123 124 (void)signal(SIGALRM, timedout); 125 (void)alarm(timeout); 126 (void)signal(SIGQUIT, SIG_IGN); 127 (void)signal(SIGINT, SIG_IGN); 128 (void)setpriority(PRIO_PROCESS, 0, 0); 129 130 openlog("login", LOG_ODELAY, LOG_AUTH); 131 132 /* 133 * -p is used by getty to tell login not to destroy the environment 134 * -f is used to skip a second login authentication 135 * -h is used by other servers to pass the name of the remote 136 * host to login so that it may be placed in utmp and wtmp 137 */ 138 domain = NULL; 139 if (gethostname(localhost, sizeof(localhost)) < 0) 140 syslog(LOG_ERR, "couldn't get local hostname: %m"); 141 else 142 domain = strchr(localhost, '.'); 143 144 fflag = hflag = pflag = 0; 145 uid = getuid(); 146 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 147 switch (ch) { 148 case 'f': 149 fflag = 1; 150 break; 151 case 'h': 152 if (uid) 153 errx(1, "-h option: %s", strerror(EPERM)); 154 hflag = 1; 155 if (domain && (p = strchr(optarg, '.')) && 156 strcasecmp(p, domain) == 0) 157 *p = 0; 158 hostname = optarg; 159 break; 160 case 'p': 161 pflag = 1; 162 break; 163 case '?': 164 default: 165 if (!uid) 166 syslog(LOG_ERR, "invalid flag %c", ch); 167 (void)fprintf(stderr, 168 "usage: login [-fp] [-h hostname] [username]\n"); 169 exit(1); 170 } 171 argc -= optind; 172 argv += optind; 173 174 if (*argv) { 175 username = *argv; 176 ask = 0; 177 } else 178 ask = 1; 179 180 for (cnt = getdtablesize(); cnt > 2; cnt--) 181 (void)close(cnt); 182 183 ttyn = ttyname(STDIN_FILENO); 184 if (ttyn == NULL || *ttyn == '\0') { 185 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 186 ttyn = tname; 187 } 188 if (tty = strrchr(ttyn, '/')) 189 ++tty; 190 else 191 tty = ttyn; 192 193 for (cnt = 0;; ask = 1) { 194 if (ask) { 195 fflag = 0; 196 getloginname(); 197 } 198 rootlogin = 0; 199 #ifdef KERBEROS 200 if ((instance = strchr(username, '.')) != NULL) { 201 if (strncmp(instance, ".root", 5) == 0) 202 rootlogin = 1; 203 *instance++ = '\0'; 204 } else 205 instance = ""; 206 #endif 207 if (strlen(username) > UT_NAMESIZE) 208 username[UT_NAMESIZE] = '\0'; 209 210 /* 211 * Note if trying multiple user names; log failures for 212 * previous user name, but don't bother logging one failure 213 * for nonexistent name (mistyped username). 214 */ 215 if (failures && strcmp(tbuf, username)) { 216 if (failures > (pwd ? 0 : 1)) 217 badlogin(tbuf); 218 failures = 0; 219 } 220 (void)strcpy(tbuf, username); 221 222 if (pwd = getpwnam(username)) 223 salt = pwd->pw_passwd; 224 else 225 salt = "xx"; 226 227 /* 228 * if we have a valid account name, and it doesn't have a 229 * password, or the -f option was specified and the caller 230 * is root or the caller isn't changing their uid, don't 231 * authenticate. 232 */ 233 if (pwd && (*pwd->pw_passwd == '\0' || 234 fflag && (uid == 0 || uid == pwd->pw_uid))) 235 break; 236 fflag = 0; 237 if (pwd && pwd->pw_uid == 0) 238 rootlogin = 1; 239 240 (void)setpriority(PRIO_PROCESS, 0, -4); 241 242 p = getpass("Password:"); 243 244 if (pwd) { 245 #ifdef KERBEROS 246 rval = klogin(pwd, instance, localhost, p); 247 if (rval != 0 && rootlogin && pwd->pw_uid != 0) 248 rootlogin = 0; 249 if (rval == 0) 250 authok = 1; 251 else if (rval == 1) 252 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 253 #else 254 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 255 #endif 256 } 257 memset(p, 0, strlen(p)); 258 259 (void)setpriority(PRIO_PROCESS, 0, 0); 260 261 /* 262 * If trying to log in as root without Kerberos, 263 * but with insecure terminal, refuse the login attempt. 264 */ 265 #ifdef KERBEROS 266 if (authok == 0) 267 #endif 268 if (pwd && rootlogin && !rootterm(tty)) { 269 (void)fprintf(stderr, 270 "%s login refused on this terminal.\n", 271 pwd->pw_name); 272 if (hostname) 273 syslog(LOG_NOTICE, 274 "LOGIN %s REFUSED FROM %s ON TTY %s", 275 pwd->pw_name, hostname, tty); 276 else 277 syslog(LOG_NOTICE, 278 "LOGIN %s REFUSED ON TTY %s", 279 pwd->pw_name, tty); 280 continue; 281 } 282 283 if (pwd && !rval) 284 break; 285 286 (void)printf("Login incorrect\n"); 287 failures++; 288 /* we allow 10 tries, but after 3 we start backing off */ 289 if (++cnt > 3) { 290 if (cnt >= 10) { 291 badlogin(username); 292 sleepexit(1); 293 } 294 sleep((u_int)((cnt - 3) * 5)); 295 } 296 } 297 298 /* committed to login -- turn off timeout */ 299 (void)alarm((u_int)0); 300 301 endpwent(); 302 303 /* if user not super-user, check for disabled logins */ 304 if (!rootlogin) 305 checknologin(); 306 307 if (chdir(pwd->pw_dir) < 0) { 308 (void)printf("No home directory %s!\n", pwd->pw_dir); 309 if (chdir("/")) 310 exit(0); 311 pwd->pw_dir = "/"; 312 (void)printf("Logging in with home = \"/\".\n"); 313 } 314 315 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 316 317 if (pwd->pw_change || pwd->pw_expire) 318 (void)gettimeofday(&tp, (struct timezone *)NULL); 319 if (pwd->pw_change) 320 if (tp.tv_sec >= pwd->pw_change) { 321 (void)printf("Sorry -- your password has expired.\n"); 322 sleepexit(1); 323 } else if (pwd->pw_change - tp.tv_sec < 324 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 325 (void)printf("Warning: your password expires on %s", 326 ctime(&pwd->pw_change)); 327 if (pwd->pw_expire) 328 if (tp.tv_sec >= pwd->pw_expire) { 329 (void)printf("Sorry -- your account has expired.\n"); 330 sleepexit(1); 331 } else if (pwd->pw_expire - tp.tv_sec < 332 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 333 (void)printf("Warning: your account expires on %s", 334 ctime(&pwd->pw_expire)); 335 336 /* Nothing else left to fail -- really log in. */ 337 memset((void *)&utmp, 0, sizeof(utmp)); 338 (void)time(&utmp.ut_time); 339 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 340 if (hostname) 341 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 342 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 343 login(&utmp); 344 345 dolastlog(quietlog); 346 347 (void)chown(ttyn, pwd->pw_uid, 348 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 349 (void)setgid(pwd->pw_gid); 350 351 initgroups(username, pwd->pw_gid); 352 353 if (*pwd->pw_shell == '\0') 354 pwd->pw_shell = _PATH_BSHELL; 355 356 /* Destroy environment unless user has requested its preservation. */ 357 if (!pflag) 358 environ = envinit; 359 (void)setenv("HOME", pwd->pw_dir, 1); 360 (void)setenv("SHELL", pwd->pw_shell, 1); 361 if (term[0] == '\0') 362 (void)strncpy(term, stypeof(tty), sizeof(term)); 363 (void)setenv("TERM", term, 0); 364 (void)setenv("LOGNAME", pwd->pw_name, 1); 365 (void)setenv("USER", pwd->pw_name, 1); 366 (void)setenv("PATH", _PATH_DEFPATH, 0); 367 #ifdef KERBEROS 368 if (krbtkfile_env) 369 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 370 #endif 371 372 if (tty[sizeof("tty")-1] == 'd') 373 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 374 375 /* If fflag is on, assume caller/authenticator has logged root login. */ 376 if (rootlogin && fflag == 0) 377 if (hostname) 378 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 379 username, tty, hostname); 380 else 381 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 382 383 #ifdef KERBEROS 384 if (!quietlog && notickets == 1) 385 (void)printf("Warning: no Kerberos tickets issued.\n"); 386 #endif 387 388 if (!quietlog) { 389 (void)printf("%s\n\t%s %s\n\n", 390 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", 391 "The Regents of the University of California. ", 392 "All rights reserved."); 393 motd(); 394 (void)snprintf(tbuf, 395 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 396 if (stat(tbuf, &st) == 0 && st.st_size != 0) 397 (void)printf("You have %smail.\n", 398 (st.st_mtime > st.st_atime) ? "new " : ""); 399 } 400 401 (void)signal(SIGALRM, SIG_DFL); 402 (void)signal(SIGQUIT, SIG_DFL); 403 (void)signal(SIGINT, SIG_DFL); 404 (void)signal(SIGTSTP, SIG_IGN); 405 406 tbuf[0] = '-'; 407 (void)strcpy(tbuf + 1, (p = strrchr(pwd->pw_shell, '/')) ? 408 p + 1 : pwd->pw_shell); 409 410 if (setlogin(pwd->pw_name) < 0) 411 syslog(LOG_ERR, "setlogin() failure: %m"); 412 413 /* Discard permissions last so can't get killed and drop core. */ 414 if (rootlogin) 415 (void) setuid(0); 416 else 417 (void) setuid(pwd->pw_uid); 418 419 execlp(pwd->pw_shell, tbuf, 0); 420 err(1, "%s", pwd->pw_shell); 421 } 422 423 #ifdef KERBEROS 424 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 425 #else 426 #define NBUFSIZ (UT_NAMESIZE + 1) 427 #endif 428 429 void 430 getloginname() 431 { 432 int ch; 433 char *p; 434 static char nbuf[NBUFSIZ]; 435 436 for (;;) { 437 (void)printf("login: "); 438 for (p = nbuf; (ch = getchar()) != '\n'; ) { 439 if (ch == EOF) { 440 badlogin(username); 441 exit(0); 442 } 443 if (p < nbuf + (NBUFSIZ - 1)) 444 *p++ = ch; 445 } 446 if (p > nbuf) 447 if (nbuf[0] == '-') 448 (void)fprintf(stderr, 449 "login names may not start with '-'.\n"); 450 else { 451 *p = '\0'; 452 username = nbuf; 453 break; 454 } 455 } 456 } 457 458 int 459 rootterm(ttyn) 460 char *ttyn; 461 { 462 struct ttyent *t; 463 464 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 465 } 466 467 jmp_buf motdinterrupt; 468 469 void 470 motd() 471 { 472 int fd, nchars; 473 sig_t oldint; 474 char tbuf[8192]; 475 476 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 477 return; 478 oldint = signal(SIGINT, sigint); 479 if (setjmp(motdinterrupt) == 0) 480 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 481 (void)write(fileno(stdout), tbuf, nchars); 482 (void)signal(SIGINT, oldint); 483 (void)close(fd); 484 } 485 486 /* ARGSUSED */ 487 void 488 sigint(signo) 489 int signo; 490 { 491 492 longjmp(motdinterrupt, 1); 493 } 494 495 /* ARGSUSED */ 496 void 497 timedout(signo) 498 int signo; 499 { 500 501 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 502 exit(0); 503 } 504 505 void 506 checknologin() 507 { 508 int fd, nchars; 509 char tbuf[8192]; 510 511 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 512 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 513 (void)write(fileno(stdout), tbuf, nchars); 514 sleepexit(0); 515 } 516 } 517 518 void 519 dolastlog(quiet) 520 int quiet; 521 { 522 struct lastlog ll; 523 int fd; 524 525 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 526 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 527 if (!quiet) { 528 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 529 ll.ll_time != 0) { 530 (void)printf("Last login: %.*s ", 531 24-5, (char *)ctime(&ll.ll_time)); 532 if (*ll.ll_host != '\0') 533 (void)printf("from %.*s\n", 534 (int)sizeof(ll.ll_host), 535 ll.ll_host); 536 else 537 (void)printf("on %.*s\n", 538 (int)sizeof(ll.ll_line), 539 ll.ll_line); 540 } 541 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 542 } 543 memset((void *)&ll, 0, sizeof(ll)); 544 (void)time(&ll.ll_time); 545 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 546 if (hostname) 547 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 548 (void)write(fd, (char *)&ll, sizeof(ll)); 549 (void)close(fd); 550 } 551 } 552 553 void 554 badlogin(name) 555 char *name; 556 { 557 558 if (failures == 0) 559 return; 560 if (hostname) { 561 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 562 failures, failures > 1 ? "S" : "", hostname); 563 syslog(LOG_AUTHPRIV|LOG_NOTICE, 564 "%d LOGIN FAILURE%s FROM %s, %s", 565 failures, failures > 1 ? "S" : "", hostname, name); 566 } else { 567 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 568 failures, failures > 1 ? "S" : "", tty); 569 syslog(LOG_AUTHPRIV|LOG_NOTICE, 570 "%d LOGIN FAILURE%s ON %s, %s", 571 failures, failures > 1 ? "S" : "", tty, name); 572 } 573 } 574 575 #undef UNKNOWN 576 #define UNKNOWN "su" 577 578 char * 579 stypeof(ttyid) 580 char *ttyid; 581 { 582 struct ttyent *t; 583 584 return (ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 585 } 586 587 void 588 sleepexit(eval) 589 int eval; 590 { 591 592 (void)sleep(5); 593 exit(eval); 594 } 595
Indexes created Wed Oct 22 13:09:56 GMT 2025