login.c revision 1.5
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[] = "@(#)login.c 5.78 (Berkeley) 6/29/92"; 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 <signal.h> 57 #include <ttyent.h> 58 #include <syslog.h> 59 #include <setjmp.h> 60 #include <tzfile.h> 61 #include <utmp.h> 62 #include <errno.h> 63 #include <grp.h> 64 #include <pwd.h> 65 #include <unistd.h> 66 #include <stdio.h> 67 #include <stdlib.h> 68 #include <string.h> 69 #include "pathnames.h" 70 71 void badlogin __P((char *)); 72 void checknologin __P((void)); 73 void dolastlog __P((int)); 74 void getloginname __P((void)); 75 void motd __P((void)); 76 int rootterm __P((char *)); 77 void sigint __P((int)); 78 void sleepexit __P((int)); 79 char *stypeof __P((char *)); 80 void timedout __P((int)); 81 #ifdef KERBEROS 82 int klogin __P((struct passwd *, char *, char *, char *)); 83 #endif 84 85 #define TTYGRPNAME "tty" /* name of group to own ttys */ 86 87 /* 88 * This bounds the time given to login. Not a define so it can 89 * be patched on machines where it's too small. 90 */ 91 int timeout = 300; 92 93 #ifdef KERBEROS 94 int notickets = 1; 95 char *instance; 96 char *krbtkfile_env; 97 int authok; 98 #endif 99 100 struct passwd *pwd; 101 int failures; 102 char term[64], *envinit[1], *hostname, *username, *tty; 103 104 int 105 main(argc, argv) 106 int argc; 107 char *argv[]; 108 { 109 extern char **environ; 110 register int ch; 111 register char *p; 112 struct group *gr; 113 struct stat st; 114 struct timeval tp; 115 struct utmp utmp; 116 int ask, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval, uid; 117 char *domain, *salt, *ttyn; 118 char tbuf[MAXPATHLEN + 2], tname[sizeof(_PATH_TTY) + 10]; 119 char localhost[MAXHOSTNAMELEN]; 120 121 (void)signal(SIGALRM, timedout); 122 (void)alarm((u_int)timeout); 123 (void)signal(SIGQUIT, SIG_IGN); 124 (void)signal(SIGINT, SIG_IGN); 125 (void)setpriority(PRIO_PROCESS, 0, 0); 126 127 openlog("login", LOG_ODELAY, LOG_AUTH); 128 129 /* 130 * -p is used by getty to tell login not to destroy the environment 131 * -f is used to skip a second login authentication 132 * -h is used by other servers to pass the name of the remote 133 * host to login so that it may be placed in utmp and wtmp 134 */ 135 domain = NULL; 136 if (gethostname(localhost, sizeof(localhost)) < 0) 137 syslog(LOG_ERR, "couldn't get local hostname: %m"); 138 else 139 domain = index(localhost, '.'); 140 141 fflag = hflag = pflag = 0; 142 uid = getuid(); 143 while ((ch = getopt(argc, argv, "fh:p")) != EOF) 144 switch (ch) { 145 case 'f': 146 fflag = 1; 147 break; 148 case 'h': 149 if (uid) { 150 (void)fprintf(stderr, 151 "login: -h option: %s\n", strerror(EPERM)); 152 exit(1); 153 } 154 hflag = 1; 155 if (domain && (p = index(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 = rindex(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 = index(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) 248 authok = 1; 249 else if (rval == 1) 250 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 251 #else 252 rval = strcmp(crypt(p, salt), pwd->pw_passwd); 253 #endif 254 } 255 bzero(p, strlen(p)); 256 257 (void)setpriority(PRIO_PROCESS, 0, 0); 258 259 /* 260 * If trying to log in as root without Kerberos, 261 * but with insecure terminal, refuse the login attempt. 262 */ 263 #ifdef KERBEROS 264 if (authok == 0) 265 #endif 266 if (pwd && rootlogin && !rootterm(tty)) { 267 (void)fprintf(stderr, 268 "%s login refused on this terminal.\n", 269 pwd->pw_name); 270 if (hostname) 271 syslog(LOG_NOTICE, 272 "LOGIN %s REFUSED FROM %s ON TTY %s", 273 pwd->pw_name, hostname, tty); 274 else 275 syslog(LOG_NOTICE, 276 "LOGIN %s REFUSED ON TTY %s", 277 pwd->pw_name, tty); 278 continue; 279 } 280 281 if (pwd && !rval) 282 break; 283 284 (void)printf("Login incorrect\n"); 285 failures++; 286 /* we allow 10 tries, but after 3 we start backing off */ 287 if (++cnt > 3) { 288 if (cnt >= 10) { 289 badlogin(username); 290 sleepexit(1); 291 } 292 sleep((u_int)((cnt - 3) * 5)); 293 } 294 } 295 296 /* committed to login -- turn off timeout */ 297 (void)alarm((u_int)0); 298 299 endpwent(); 300 301 /* if user not super-user, check for disabled logins */ 302 if (!rootlogin) 303 checknologin(); 304 305 if (chdir(pwd->pw_dir) < 0) { 306 (void)printf("No home directory %s!\n", pwd->pw_dir); 307 if (chdir("/")) 308 exit(0); 309 pwd->pw_dir = "/"; 310 (void)printf("Logging in with home = \"/\".\n"); 311 } 312 313 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 314 315 if (pwd->pw_change || pwd->pw_expire) 316 (void)gettimeofday(&tp, (struct timezone *)NULL); 317 if (pwd->pw_change) 318 if (tp.tv_sec >= pwd->pw_change) { 319 (void)printf("Sorry -- your password has expired.\n"); 320 sleepexit(1); 321 } else if (pwd->pw_change - tp.tv_sec < 322 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 323 (void)printf("Warning: your password expires on %s", 324 ctime(&pwd->pw_change)); 325 if (pwd->pw_expire) 326 if (tp.tv_sec >= pwd->pw_expire) { 327 (void)printf("Sorry -- your account has expired.\n"); 328 sleepexit(1); 329 } else if (pwd->pw_expire - tp.tv_sec < 330 2 * DAYSPERWEEK * SECSPERDAY && !quietlog) 331 (void)printf("Warning: your account expires on %s", 332 ctime(&pwd->pw_expire)); 333 334 /* Nothing else left to fail -- really log in. */ 335 bzero((void *)&utmp, sizeof(utmp)); 336 (void)time(&utmp.ut_time); 337 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 338 if (hostname) 339 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 340 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 341 login(&utmp); 342 343 dolastlog(quietlog); 344 345 (void)chown(ttyn, pwd->pw_uid, 346 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid); 347 (void)setgid(pwd->pw_gid); 348 349 initgroups(username, pwd->pw_gid); 350 351 if (*pwd->pw_shell == '\0') 352 pwd->pw_shell = _PATH_BSHELL; 353 354 /* Destroy environment unless user has requested its preservation. */ 355 if (!pflag) 356 environ = envinit; 357 (void)setenv("HOME", pwd->pw_dir, 1); 358 (void)setenv("SHELL", pwd->pw_shell, 1); 359 if (term[0] == '\0') 360 (void)strncpy(term, stypeof(tty), sizeof(term)); 361 (void)setenv("TERM", term, 0); 362 (void)setenv("LOGNAME", pwd->pw_name, 1); 363 (void)setenv("USER", pwd->pw_name, 1); 364 (void)setenv("PATH", _PATH_DEFPATH, 0); 365 #ifdef KERBEROS 366 if (krbtkfile_env) 367 (void)setenv("KRBTKFILE", krbtkfile_env, 1); 368 #endif 369 370 if (tty[sizeof("tty")-1] == 'd') 371 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 372 373 /* If fflag is on, assume caller/authenticator has logged root login. */ 374 if (rootlogin && fflag == 0) 375 if (hostname) 376 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 377 username, tty, hostname); 378 else 379 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", username, tty); 380 381 #ifdef KERBEROS 382 if (!quietlog && notickets == 1) 383 (void)printf("Warning: no Kerberos tickets issued.\n"); 384 #endif 385 386 if (!quietlog) { 387 (void)printf( 388 "Copyright (c) 1980,1983,1986,1988,1990,1991 The Regents of the University\n%s", 389 "of California. All rights reserved.\n\n"); 390 motd(); 391 (void)snprintf(tbuf, 392 sizeof(tbuf), "%s/%s", _PATH_MAILDIR, pwd->pw_name); 393 if (stat(tbuf, &st) == 0 && st.st_size != 0) 394 (void)printf("You have %smail.\n", 395 (st.st_mtime > st.st_atime) ? "new " : ""); 396 } 397 398 (void)signal(SIGALRM, SIG_DFL); 399 (void)signal(SIGQUIT, SIG_DFL); 400 (void)signal(SIGINT, SIG_DFL); 401 (void)signal(SIGTSTP, SIG_IGN); 402 403 tbuf[0] = '-'; 404 (void)strcpy(tbuf + 1, (p = rindex(pwd->pw_shell, '/')) ? 405 p + 1 : pwd->pw_shell); 406 407 if (setlogin(pwd->pw_name) < 0) 408 syslog(LOG_ERR, "setlogin() failure: %m"); 409 410 /* Discard permissions last so can't get killed and drop core. */ 411 if (rootlogin) 412 (void) setuid(0); 413 else 414 (void) setuid(pwd->pw_uid); 415 416 execlp(pwd->pw_shell, tbuf, 0); 417 (void)fprintf(stderr, "%s: %s\n", pwd->pw_shell, strerror(errno)); 418 exit(1); 419 } 420 421 #ifdef KERBEROS 422 #define NBUFSIZ (UT_NAMESIZE + 1 + 5) /* .root suffix */ 423 #else 424 #define NBUFSIZ (UT_NAMESIZE + 1) 425 #endif 426 427 void 428 getloginname() 429 { 430 register int ch; 431 register char *p; 432 static char nbuf[NBUFSIZ]; 433 434 for (;;) { 435 (void)printf("login: "); 436 for (p = nbuf; (ch = getchar()) != '\n'; ) { 437 if (ch == EOF) { 438 badlogin(username); 439 exit(0); 440 } 441 if (p < nbuf + (NBUFSIZ - 1)) 442 *p++ = ch; 443 } 444 if (p > nbuf) 445 if (nbuf[0] == '-') 446 (void)fprintf(stderr, 447 "login names may not start with '-'.\n"); 448 else { 449 *p = '\0'; 450 username = nbuf; 451 break; 452 } 453 } 454 } 455 456 int 457 rootterm(ttyn) 458 char *ttyn; 459 { 460 struct ttyent *t; 461 462 return((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 463 } 464 465 jmp_buf motdinterrupt; 466 467 void 468 motd() 469 { 470 register int fd, nchars; 471 sig_t oldint; 472 char tbuf[8192]; 473 474 if ((fd = open(_PATH_MOTDFILE, O_RDONLY, 0)) < 0) 475 return; 476 oldint = signal(SIGINT, sigint); 477 if (setjmp(motdinterrupt) == 0) 478 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 479 (void)write(fileno(stdout), tbuf, nchars); 480 (void)signal(SIGINT, oldint); 481 (void)close(fd); 482 } 483 484 /* ARGSUSED */ 485 void 486 sigint(signo) 487 int signo; 488 { 489 longjmp(motdinterrupt, 1); 490 } 491 492 /* ARGSUSED */ 493 void 494 timedout(signo) 495 int signo; 496 { 497 (void)fprintf(stderr, "Login timed out after %d seconds\n", timeout); 498 exit(0); 499 } 500 501 void 502 checknologin() 503 { 504 register int fd, nchars; 505 char tbuf[8192]; 506 507 if ((fd = open(_PATH_NOLOGIN, O_RDONLY, 0)) >= 0) { 508 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0) 509 (void)write(fileno(stdout), tbuf, nchars); 510 sleepexit(0); 511 } 512 } 513 514 void 515 dolastlog(quiet) 516 int quiet; 517 { 518 struct lastlog ll; 519 int fd; 520 521 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 522 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 523 if (!quiet) { 524 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 525 ll.ll_time != 0) { 526 (void)printf("Last login: %.*s ", 527 24-5, (char *)ctime(&ll.ll_time)); 528 if (*ll.ll_host != '\0') 529 (void)printf("from %.*s\n", 530 (int)sizeof(ll.ll_host), 531 ll.ll_host); 532 else 533 (void)printf("on %.*s\n", 534 (int)sizeof(ll.ll_line), 535 ll.ll_line); 536 } 537 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 538 } 539 bzero((void *)&ll, sizeof(ll)); 540 (void)time(&ll.ll_time); 541 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 542 if (hostname) 543 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 544 (void)write(fd, (char *)&ll, sizeof(ll)); 545 (void)close(fd); 546 } 547 } 548 549 void 550 badlogin(name) 551 char *name; 552 { 553 if (failures == 0) 554 return; 555 if (hostname) { 556 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 557 failures, failures > 1 ? "S" : "", hostname); 558 syslog(LOG_AUTHPRIV|LOG_NOTICE, 559 "%d LOGIN FAILURE%s FROM %s, %s", 560 failures, failures > 1 ? "S" : "", hostname, name); 561 } else { 562 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 563 failures, failures > 1 ? "S" : "", tty); 564 syslog(LOG_AUTHPRIV|LOG_NOTICE, 565 "%d LOGIN FAILURE%s ON %s, %s", 566 failures, failures > 1 ? "S" : "", tty, name); 567 } 568 } 569 570 #undef UNKNOWN 571 #define UNKNOWN "su" 572 573 char * 574 stypeof(ttyid) 575 char *ttyid; 576 { 577 struct ttyent *t; 578 579 return(ttyid && (t = getttynam(ttyid)) ? t->ty_type : UNKNOWN); 580 } 581 582 void 583 sleepexit(eval) 584 int eval; 585 { 586 (void)sleep((u_int)5); 587 exit(eval); 588 } 589
Indexes created Wed Oct 01 07:09:59 GMT 2025