login.c revision 83519
1226048Sobrien/*- 2133359Sobrien * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 3267843Sdelphij * The Regents of the University of California. All rights reserved. 4133359Sobrien * 5133359Sobrien * Redistribution and use in source and binary forms, with or without 6133359Sobrien * modification, are permitted provided that the following conditions 7169962Sobrien * are met: 8133359Sobrien * 1. Redistributions of source code must retain the above copyright 9133359Sobrien * notice, this list of conditions and the following disclaimer. 10133359Sobrien * 2. Redistributions in binary form must reproduce the above copyright 11133359Sobrien * notice, this list of conditions and the following disclaimer in the 12133359Sobrien * documentation and/or other materials provided with the distribution. 13133359Sobrien * 3. All advertising materials mentioning features or use of this software 14133359Sobrien * must display the following acknowledgement: 15133359Sobrien * This product includes software developed by the University of 16186690Sobrien * California, Berkeley and its contributors. 17133359Sobrien * 4. Neither the name of the University nor the names of its contributors 18133359Sobrien * may be used to endorse or promote products derived from this software 19133359Sobrien * without specific prior written permission. 20133359Sobrien * 21133359Sobrien * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22133359Sobrien * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23133359Sobrien * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24133359Sobrien * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25133359Sobrien * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26133359Sobrien * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27133359Sobrien * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28133359Sobrien * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29133359Sobrien * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30133359Sobrien * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31133359Sobrien * SUCH DAMAGE. 32133359Sobrien */ 33133359Sobrien 34133359Sobrien#if 0 35133359Sobrienstatic char copyright[] = 36133359Sobrien"@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\ 37133359Sobrien The Regents of the University of California. All rights reserved.\n"; 38133359Sobrien#endif 39133359Sobrien 40133359Sobrien#ifndef lint 41133359Sobrien#if 0 42133359Sobrienstatic char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; 43133359Sobrien#endif 44133359Sobrienstatic const char rcsid[] = 45133359Sobrien "$FreeBSD: head/usr.bin/login/login.c 83519 2001-09-15 17:09:39Z rwatson $"; 46133359Sobrien#endif /* not lint */ 47133359Sobrien 48133359Sobrien/* 49133359Sobrien * login [ name ] 50133359Sobrien * login -h hostname (for telnetd, etc.) 51133359Sobrien * login -f name (for pre-authenticated login: datakit, xterm, etc.) 52133359Sobrien */ 53133359Sobrien 54133359Sobrien#include <sys/copyright.h> 55133359Sobrien#include <sys/param.h> 56133359Sobrien#include <sys/stat.h> 57133359Sobrien#include <sys/socket.h> 58133359Sobrien#include <sys/time.h> 59133359Sobrien#include <sys/resource.h> 60133359Sobrien#include <sys/file.h> 61133359Sobrien#include <netinet/in.h> 62133359Sobrien#include <arpa/inet.h> 63133359Sobrien 64133359Sobrien#include <err.h> 65133359Sobrien#include <errno.h> 66133359Sobrien#include <grp.h> 67133359Sobrien#include <libutil.h> 68133359Sobrien#include <login_cap.h> 69133359Sobrien#include <netdb.h> 70133359Sobrien#include <pwd.h> 71133359Sobrien#include <setjmp.h> 72133359Sobrien#include <signal.h> 73133359Sobrien#include <stdio.h> 74133359Sobrien#include <stdlib.h> 75133359Sobrien#include <string.h> 76133359Sobrien#include <syslog.h> 77133359Sobrien#include <ttyent.h> 78133359Sobrien#include <unistd.h> 79133359Sobrien#include <utmp.h> 80133359Sobrien 81133359Sobrien#include <security/pam_appl.h> 82133359Sobrien#include <security/pam_misc.h> 83133359Sobrien#include <sys/wait.h> 84133359Sobrien 85133359Sobrien#include "pathnames.h" 86133359Sobrien 87133359Sobrien/* wrapper for KAME-special getnameinfo() */ 88133359Sobrien#ifndef NI_WITHSCOPEID 89133359Sobrien#define NI_WITHSCOPEID 0 90133359Sobrien#endif 91133359Sobrien 92133359Sobrienvoid badlogin __P((char *)); 93133359Sobrienvoid dolastlog __P((int)); 94133359Sobrienvoid getloginname __P((void)); 95133359Sobrienvoid motd __P((char *)); 96133359Sobrienint rootterm __P((char *)); 97133359Sobrienvoid sigint __P((int)); 98133359Sobrienvoid sleepexit __P((int)); 99133359Sobrienvoid refused __P((char *,char *,int)); 100133359Sobrienchar *stypeof __P((char *)); 101133359Sobrienvoid timedout __P((int)); 102133359Sobrienint login_access __P((char *, char *)); 103133359Sobrienvoid login_fbtab __P((char *, uid_t, gid_t)); 104133359Sobrien 105133359Sobrienstatic int auth_pam __P((void)); 106133359Sobrienstatic int export_pam_environment __P((void)); 107133359Sobrienstatic int ok_to_export __P((const char *)); 108169942Sobrien 109169942Sobrienstatic pam_handle_t *pamh = NULL; 110169942Sobrienstatic char **environ_pam; 111186690Sobrien 112133359Sobrien#define PAM_END { \ 113267843Sdelphij if ((e = pam_setcred(pamh, PAM_DELETE_CRED)) != PAM_SUCCESS) \ 114133359Sobrien syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, e)); \ 115133359Sobrien if ((e = pam_close_session(pamh,0)) != PAM_SUCCESS) \ 116159764Sobrien syslog(LOG_ERR, "pam_close_session: %s", pam_strerror(pamh, e)); \ 117159764Sobrien if ((e = pam_end(pamh, e)) != PAM_SUCCESS) \ 118159764Sobrien syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e)); \ 119159764Sobrien} 120159764Sobrien 121159764Sobrienstatic int auth_traditional __P((void)); 122169942Sobrienextern void login __P((struct utmp *)); 123169942Sobrienstatic void usage __P((void)); 124169942Sobrien 125169942Sobrien#define TTYGRPNAME "tty" /* name of group to own ttys */ 126169942Sobrien#define DEFAULT_BACKOFF 3 127186690Sobrien#define DEFAULT_RETRIES 10 128169942Sobrien#define DEFAULT_PROMPT "login: " 129169942Sobrien#define DEFAULT_PASSWD_PROMPT "Password:" 130169942Sobrien 131169942Sobrien/* 132169942Sobrien * This bounds the time given to login. Not a define so it can 133169942Sobrien * be patched on machines where it's too small. 134186690Sobrien */ 135186690Sobrienu_int timeout = 300; 136186690Sobrien 137186690Sobrien/* Buffer for signal handling of timeout */ 138186690Sobrienjmp_buf timeout_buf; 139186690Sobrien 140186690Sobrienstruct passwd *pwd; 141186690Sobrienint failures; 142186690Sobrienchar *term, *envinit[1], *hostname, *passwd_prompt, *prompt, *tty, *username; 143186690Sobrienchar full_hostname[MAXHOSTNAMELEN]; 144186690Sobrien 145186690Sobrienint 146186690Sobrienmain(argc, argv) 147186690Sobrien int argc; 148186690Sobrien char *argv[]; 149186690Sobrien{ 150186690Sobrien extern char **environ; 151186690Sobrien struct group *gr; 152186690Sobrien struct stat st; 153226048Sobrien struct timeval tp; 154226048Sobrien struct utmp utmp; 155226048Sobrien int rootok, retries, backoff; 156226048Sobrien int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval; 157226048Sobrien time_t warntime; 158226048Sobrien uid_t uid, euid; 159267843Sdelphij gid_t egid; 160267843Sdelphij char *p, *ttyn; 161267843Sdelphij char tbuf[MAXPATHLEN + 2]; 162267843Sdelphij char tname[sizeof(_PATH_TTY) + 10]; 163267843Sdelphij char *shell = NULL; 164226048Sobrien login_cap_t *lc = NULL; 165226048Sobrien pid_t pid; 166226048Sobrien int e; 167226048Sobrien 168226048Sobrien (void)signal(SIGQUIT, SIG_IGN); 169267843Sdelphij (void)signal(SIGINT, SIG_IGN); 170267843Sdelphij (void)signal(SIGHUP, SIG_IGN); 171267843Sdelphij if (setjmp(timeout_buf)) { 172267843Sdelphij if (failures) 173 badlogin(tbuf); 174 (void)fprintf(stderr, "Login timed out after %d seconds\n", 175 timeout); 176 exit(0); 177 } 178 (void)signal(SIGALRM, timedout); 179 (void)alarm(timeout); 180 (void)setpriority(PRIO_PROCESS, 0, 0); 181 182 openlog("login", LOG_ODELAY, LOG_AUTH); 183 184 /* 185 * -p is used by getty to tell login not to destroy the environment 186 * -f is used to skip a second login authentication 187 * -h is used by other servers to pass the name of the remote 188 * host to login so that it may be placed in utmp and wtmp 189 */ 190 *full_hostname = '\0'; 191 term = NULL; 192 193 fflag = hflag = pflag = 0; 194 uid = getuid(); 195 euid = geteuid(); 196 egid = getegid(); 197 while ((ch = getopt(argc, argv, "fh:p")) != -1) 198 switch (ch) { 199 case 'f': 200 fflag = 1; 201 break; 202 case 'h': 203 if (uid) 204 errx(1, "-h option: %s", strerror(EPERM)); 205 hflag = 1; 206 if (strlcpy(full_hostname, optarg, 207 sizeof(full_hostname)) >= sizeof(full_hostname)) 208 errx(1, "-h option: %s: exceeds maximum " 209 "hostname size", optarg); 210 211 trimdomain(optarg, UT_HOSTSIZE); 212 213 if (strlen(optarg) > UT_HOSTSIZE) { 214 struct addrinfo hints, *res; 215 int ga_err; 216 217 memset(&hints, 0, sizeof(hints)); 218 hints.ai_family = AF_UNSPEC; 219 ga_err = getaddrinfo(optarg, NULL, &hints, 220 &res); 221 if (ga_err == 0) { 222 char hostbuf[MAXHOSTNAMELEN]; 223 224 getnameinfo(res->ai_addr, 225 res->ai_addrlen, 226 hostbuf, 227 sizeof(hostbuf), NULL, 0, 228 NI_NUMERICHOST| 229 NI_WITHSCOPEID); 230 optarg = strdup(hostbuf); 231 if (optarg == NULL) { 232 syslog(LOG_NOTICE, 233 "strdup(): %m"); 234 sleepexit(1); 235 } 236 } else 237 optarg = "invalid hostname"; 238 if (res != NULL) 239 freeaddrinfo(res); 240 } 241 hostname = optarg; 242 break; 243 case 'p': 244 pflag = 1; 245 break; 246 case '?': 247 default: 248 if (!uid) 249 syslog(LOG_ERR, "invalid flag %c", ch); 250 usage(); 251 } 252 argc -= optind; 253 argv += optind; 254 255 if (*argv) { 256 username = *argv; 257 ask = 0; 258 } else 259 ask = 1; 260 261 for (cnt = getdtablesize(); cnt > 2; cnt--) 262 (void)close(cnt); 263 264 ttyn = ttyname(STDIN_FILENO); 265 if (ttyn == NULL || *ttyn == '\0') { 266 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 267 ttyn = tname; 268 } 269 if ((tty = strrchr(ttyn, '/')) != NULL) 270 ++tty; 271 else 272 tty = ttyn; 273 274 /* 275 * Get "login-retries" & "login-backoff" from default class 276 */ 277 lc = login_getclass(NULL); 278 prompt = login_getcapstr(lc, "prompt", DEFAULT_PROMPT, DEFAULT_PROMPT); 279 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 280 DEFAULT_PASSWD_PROMPT, DEFAULT_PASSWD_PROMPT); 281 retries = login_getcapnum(lc, "login-retries", DEFAULT_RETRIES, 282 DEFAULT_RETRIES); 283 backoff = login_getcapnum(lc, "login-backoff", DEFAULT_BACKOFF, 284 DEFAULT_BACKOFF); 285 login_close(lc); 286 lc = NULL; 287 288 for (cnt = 0;; ask = 1) { 289 if (ask) { 290 fflag = 0; 291 getloginname(); 292 } 293 rootlogin = 0; 294 rootok = rootterm(tty); /* Default (auth may change) */ 295 296 if (strlen(username) > UT_NAMESIZE) 297 username[UT_NAMESIZE] = '\0'; 298 299 /* 300 * Note if trying multiple user names; log failures for 301 * previous user name, but don't bother logging one failure 302 * for nonexistent name (mistyped username). 303 */ 304 if (failures && strcmp(tbuf, username)) { 305 if (failures > (pwd ? 0 : 1)) 306 badlogin(tbuf); 307 } 308 (void)strlcpy(tbuf, username, sizeof(tbuf)); 309 310 pwd = getpwnam(username); 311 312 /* 313 * if we have a valid account name, and it doesn't have a 314 * password, or the -f option was specified and the caller 315 * is root or the caller isn't changing their uid, don't 316 * authenticate. 317 */ 318 if (pwd != NULL) { 319 if (pwd->pw_uid == 0) 320 rootlogin = 1; 321 322 if (fflag && (uid == (uid_t)0 || 323 uid == (uid_t)pwd->pw_uid)) { 324 /* already authenticated */ 325 break; 326 } else if (pwd->pw_passwd[0] == '\0') { 327 if (!rootlogin || rootok) { 328 /* pretend password okay */ 329 rval = 0; 330 goto ttycheck; 331 } 332 } 333 } 334 335 fflag = 0; 336 337 (void)setpriority(PRIO_PROCESS, 0, -4); 338 339 /* 340 * Try to authenticate using PAM. If a PAM system error 341 * occurs, perhaps because of a botched configuration, 342 * then fall back to using traditional Unix authentication. 343 */ 344 if ((rval = auth_pam()) == -1) 345 rval = auth_traditional(); 346 347 (void)setpriority(PRIO_PROCESS, 0, 0); 348 349 /* 350 * PAM authentication may have changed "pwd" to the 351 * entry for the template user. Check again to see if 352 * this is a root login after all. 353 */ 354 if (pwd != NULL && pwd->pw_uid == 0) 355 rootlogin = 1; 356 357 ttycheck: 358 /* 359 * If trying to log in as root without Kerberos, 360 * but with insecure terminal, refuse the login attempt. 361 */ 362 if (pwd && !rval) { 363 if (rootlogin && !rootok) 364 refused(NULL, "NOROOT", 0); 365 else /* valid password & authenticated */ 366 break; 367 } 368 369 (void)printf("Login incorrect\n"); 370 failures++; 371 372 /* 373 * we allow up to 'retry' (10) tries, 374 * but after 'backoff' (3) we start backing off 375 */ 376 if (++cnt > backoff) { 377 if (cnt >= retries) { 378 badlogin(username); 379 sleepexit(1); 380 } 381 sleep((u_int)((cnt - backoff) * 5)); 382 } 383 } 384 385 /* committed to login -- turn off timeout */ 386 (void)alarm((u_int)0); 387 (void)signal(SIGHUP, SIG_DFL); 388 389 endpwent(); 390 391 /* 392 * Establish the login class. 393 */ 394 lc = login_getpwclass(pwd); 395 396 quietlog = login_getcapbool(lc, "hushlogin", 0); 397 /* 398 * Switching needed for NFS with root access disabled. 399 * 400 * XXX: This change fails to modify the additional groups for the 401 * process, and as such, may restrict rights normally granted 402 * through those groups. 403 */ 404 (void)setegid(pwd->pw_gid); 405 (void)seteuid(rootlogin ? 0 : pwd->pw_uid); 406 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 407 if (login_getcapbool(lc, "requirehome", 0)) 408 refused("Home directory not available", "HOMEDIR", 1); 409 if (chdir("/") < 0) 410 refused("Cannot find root directory", "ROOTDIR", 1); 411 if (!quietlog || *pwd->pw_dir) 412 printf("No home directory.\nLogging in with home = \"/\".\n"); 413 pwd->pw_dir = "/"; 414 } 415 (void)seteuid(euid); 416 (void)setegid(egid); 417 if (!quietlog) 418 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 419 420 if (pwd->pw_change || pwd->pw_expire) 421 (void)gettimeofday(&tp, (struct timezone *)NULL); 422 423#define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 424 425 warntime = login_getcaptime(lc, "warnexpire", DEFAULT_WARN, 426 DEFAULT_WARN); 427 428 if (pwd->pw_expire) { 429 if (tp.tv_sec >= pwd->pw_expire) { 430 refused("Sorry -- your account has expired", "EXPIRED", 431 1); 432 } else if (pwd->pw_expire - tp.tv_sec < warntime && !quietlog) 433 (void)printf("Warning: your account expires on %s", 434 ctime(&pwd->pw_expire)); 435 } 436 437 if (lc != NULL) { 438 if (hostname) { 439 struct addrinfo hints, *res; 440 int ga_err; 441 442 memset(&hints, 0, sizeof(hints)); 443 hints.ai_family = AF_UNSPEC; 444 ga_err = getaddrinfo(full_hostname, NULL, &hints, 445 &res); 446 if (ga_err == 0) { 447 char hostbuf[MAXHOSTNAMELEN]; 448 449 getnameinfo(res->ai_addr, res->ai_addrlen, 450 hostbuf, sizeof(hostbuf), NULL, 0, 451 NI_NUMERICHOST|NI_WITHSCOPEID); 452 if ((optarg = strdup(hostbuf)) == NULL) { 453 syslog(LOG_NOTICE, "strdup(): %m"); 454 sleepexit(1); 455 } 456 } else 457 optarg = NULL; 458 if (res != NULL) 459 freeaddrinfo(res); 460 if (!auth_hostok(lc, full_hostname, optarg)) 461 refused("Permission denied", "HOST", 1); 462 } 463 464 if (!auth_ttyok(lc, tty)) 465 refused("Permission denied", "TTY", 1); 466 467 if (!auth_timeok(lc, time(NULL))) 468 refused("Logins not available right now", "TIME", 1); 469 } 470 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 471 if (*pwd->pw_shell == '\0') 472 pwd->pw_shell = _PATH_BSHELL; 473 if (*shell == '\0') /* Not overridden */ 474 shell = pwd->pw_shell; 475 if ((shell = strdup(shell)) == NULL) { 476 syslog(LOG_NOTICE, "strdup(): %m"); 477 sleepexit(1); 478 } 479 480#ifdef LOGIN_ACCESS 481 if (login_access(pwd->pw_name, hostname ? full_hostname : tty) == 0) 482 refused("Permission denied", "ACCESS", 1); 483#endif /* LOGIN_ACCESS */ 484 485 /* Nothing else left to fail -- really log in. */ 486 memset((void *)&utmp, 0, sizeof(utmp)); 487 (void)time(&utmp.ut_time); 488 (void)strncpy(utmp.ut_name, username, sizeof(utmp.ut_name)); 489 if (hostname) 490 (void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host)); 491 (void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line)); 492 login(&utmp); 493 494 dolastlog(quietlog); 495 496 /* 497 * Set device protections, depending on what terminal the 498 * user is logged in. This feature is used on Suns to give 499 * console users better privacy. 500 */ 501 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 502 503 /* 504 * Clear flags of the tty. None should be set, and when the 505 * user sets them otherwise, this can cause the chown to fail. 506 * Since it isn't clear that flags are useful on character 507 * devices, we just clear them. 508 */ 509 if (chflags(ttyn, 0) && errno != EOPNOTSUPP) 510 syslog(LOG_ERR, "chmod(%s): %m", ttyn); 511 if (chown(ttyn, pwd->pw_uid, 512 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 513 syslog(LOG_ERR, "chmod(%s): %m", ttyn); 514 515 516 /* 517 * Preserve TERM if it happens to be already set. 518 */ 519 if ((term = getenv("TERM")) != NULL) { 520 if ((term = strdup(term)) == NULL) { 521 syslog(LOG_NOTICE, 522 "strdup(): %m"); 523 sleepexit(1); 524 } 525 } 526 527 /* 528 * Exclude cons/vt/ptys only, assume dialup otherwise 529 * TODO: Make dialup tty determination a library call 530 * for consistency (finger etc.) 531 */ 532 if (hostname==NULL && isdialuptty(tty)) 533 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 534 535#ifdef LOGALL 536 /* 537 * Syslog each successful login, so we don't have to watch hundreds 538 * of wtmp or lastlogin files. 539 */ 540 if (hostname) 541 syslog(LOG_INFO, "login from %s on %s as %s", 542 full_hostname, tty, pwd->pw_name); 543 else 544 syslog(LOG_INFO, "login on %s as %s", 545 tty, pwd->pw_name); 546#endif 547 548 /* 549 * If fflag is on, assume caller/authenticator has logged root login. 550 */ 551 if (rootlogin && fflag == 0) 552 { 553 if (hostname) 554 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 555 username, tty, full_hostname); 556 else 557 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 558 username, tty); 559 } 560 561 /* 562 * Destroy environment unless user has requested its preservation. 563 * We need to do this before setusercontext() because that may 564 * set or reset some environment variables. 565 */ 566 if (!pflag) 567 environ = envinit; 568 569 /* 570 * PAM modules might add supplementary groups during pam_setcred(). 571 */ 572 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 573 syslog(LOG_ERR, "setusercontext() failed - exiting"); 574 exit(1); 575 } 576 577 if (pamh) { 578 if ((e = pam_open_session(pamh, 0)) != PAM_SUCCESS) { 579 syslog(LOG_ERR, "pam_open_session: %s", 580 pam_strerror(pamh, e)); 581 } else if ((e = pam_setcred(pamh, PAM_ESTABLISH_CRED)) 582 != PAM_SUCCESS) { 583 syslog(LOG_ERR, "pam_setcred: %s", 584 pam_strerror(pamh, e)); 585 } 586 587 /* 588 * Add any environmental variables that the 589 * PAM modules may have set. 590 * Call *after* opening session! 591 */ 592 if (pamh) { 593 environ_pam = pam_getenvlist(pamh); 594 if (environ_pam) 595 export_pam_environment(); 596 } 597 598 /* 599 * We must fork() before setuid() because we need to call 600 * pam_close_session() as root. 601 */ 602 pid = fork(); 603 if (pid < 0) { 604 err(1, "fork"); 605 PAM_END; 606 exit(0); 607 } else if (pid) { 608 /* parent - wait for child to finish, then cleanup 609 session */ 610 wait(NULL); 611 PAM_END; 612 exit(0); 613 } else { 614 if ((e = pam_end(pamh, PAM_DATA_SILENT)) != PAM_SUCCESS) 615 syslog(LOG_ERR, "pam_end: %s", 616 pam_strerror(pamh, e)); 617 } 618 } 619 620 /* 621 * We don't need to be root anymore, so 622 * set the user and session context 623 */ 624 if (setlogin(username) != 0) { 625 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 626 exit(1); 627 } 628 if (setusercontext(lc, pwd, pwd->pw_uid, 629 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 630 syslog(LOG_ERR, "setusercontext() failed - exiting"); 631 exit(1); 632 } 633 634 (void)setenv("SHELL", pwd->pw_shell, 1); 635 (void)setenv("HOME", pwd->pw_dir, 1); 636 if (term != NULL && *term != '\0') 637 (void)setenv("TERM", term, 1); /* Preset overrides */ 638 else { 639 (void)setenv("TERM", stypeof(tty), 0); /* Fallback doesn't */ 640 } 641 (void)setenv("LOGNAME", username, 1); 642 (void)setenv("USER", username, 1); 643 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0); 644 645 if (!quietlog) { 646 char *cw; 647 648 cw = login_getcapstr(lc, "copyright", NULL, NULL); 649 if (cw != NULL && access(cw, F_OK) == 0) 650 motd(cw); 651 else 652 (void)printf("%s\n\t%s %s\n", 653 "Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994", 654 "The Regents of the University of California. ", 655 "All rights reserved."); 656 657 (void)printf("\n"); 658 659 cw = login_getcapstr(lc, "welcome", NULL, NULL); 660 if (cw == NULL || access(cw, F_OK) != 0) 661 cw = _PATH_MOTDFILE; 662 motd(cw); 663 664 cw = getenv("MAIL"); /* $MAIL may have been set by class */ 665 if (cw != NULL) 666 strlcpy(tbuf, cw, sizeof(tbuf)); 667 else 668 snprintf(tbuf, sizeof(tbuf), "%s/%s", _PATH_MAILDIR, 669 pwd->pw_name); 670 if (stat(tbuf, &st) == 0 && st.st_size != 0) 671 (void)printf("You have %smail.\n", 672 (st.st_mtime > st.st_atime) ? "new " : ""); 673 } 674 675 login_close(lc); 676 677 (void)signal(SIGALRM, SIG_DFL); 678 (void)signal(SIGQUIT, SIG_DFL); 679 (void)signal(SIGINT, SIG_DFL); 680 (void)signal(SIGTSTP, SIG_IGN); 681 682 /* 683 * Login shells have a leading '-' in front of argv[0] 684 */ 685 if (snprintf(tbuf, sizeof(tbuf), "-%s", 686 (p = strrchr(pwd->pw_shell, '/')) ? p + 1 : pwd->pw_shell) >= 687 sizeof(tbuf)) { 688 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 689 username); 690 errx(1, "shell exceeds maximum pathname size"); 691 } 692 693 execlp(shell, tbuf, (char *)0); 694 err(1, "%s", shell); 695} 696 697static int 698auth_traditional() 699{ 700 int rval; 701 char *p; 702 char *ep; 703 char *salt; 704 705 rval = 1; 706 salt = pwd != NULL ? pwd->pw_passwd : "xx"; 707 708 p = getpass(passwd_prompt); 709 ep = crypt(p, salt); 710 711 if (pwd) { 712 if (!p[0] && pwd->pw_passwd[0]) 713 ep = ":"; 714 if (strcmp(ep, pwd->pw_passwd) == 0) 715 rval = 0; 716 } 717 718 /* clear entered password */ 719 memset(p, 0, strlen(p)); 720 return rval; 721} 722 723/* 724 * Attempt to authenticate the user using PAM. Returns 0 if the user is 725 * authenticated, or 1 if not authenticated. If some sort of PAM system 726 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 727 * function returns -1. This can be used as an indication that we should 728 * fall back to a different authentication mechanism. 729 */ 730static int 731auth_pam() 732{ 733 const char *tmpl_user; 734 const void *item; 735 int rval; 736 int e; 737 static struct pam_conv conv = { misc_conv, NULL }; 738 739 if ((e = pam_start("login", username, &conv, &pamh)) != PAM_SUCCESS) { 740 syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e)); 741 return -1; 742 } 743 if ((e = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS) { 744 syslog(LOG_ERR, "pam_set_item(PAM_TTY): %s", 745 pam_strerror(pamh, e)); 746 return -1; 747 } 748 if (hostname != NULL && 749 (e = pam_set_item(pamh, PAM_RHOST, full_hostname)) != PAM_SUCCESS) { 750 syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s", 751 pam_strerror(pamh, e)); 752 return -1; 753 } 754 e = pam_authenticate(pamh, 0); 755 switch (e) { 756 757 case PAM_SUCCESS: 758 /* 759 * With PAM we support the concept of a "template" 760 * user. The user enters a login name which is 761 * authenticated by PAM, usually via a remote service 762 * such as RADIUS or TACACS+. If authentication 763 * succeeds, a different but related "template" name 764 * is used for setting the credentials, shell, and 765 * home directory. The name the user enters need only 766 * exist on the remote authentication server, but the 767 * template name must be present in the local password 768 * database. 769 * 770 * This is supported by two various mechanisms in the 771 * individual modules. However, from the application's 772 * point of view, the template user is always passed 773 * back as a changed value of the PAM_USER item. 774 */ 775 if ((e = pam_get_item(pamh, PAM_USER, &item)) == 776 PAM_SUCCESS) { 777 tmpl_user = (const char *) item; 778 if (strcmp(username, tmpl_user) != 0) 779 pwd = getpwnam(tmpl_user); 780 } else 781 syslog(LOG_ERR, "Couldn't get PAM_USER: %s", 782 pam_strerror(pamh, e)); 783 rval = 0; 784 break; 785 786 case PAM_AUTH_ERR: 787 case PAM_USER_UNKNOWN: 788 case PAM_MAXTRIES: 789 rval = 1; 790 break; 791 792 default: 793 syslog(LOG_ERR, "pam_authenticate: %s", pam_strerror(pamh, e)); 794 rval = -1; 795 break; 796 } 797 798 if (rval == 0) { 799 e = pam_acct_mgmt(pamh, 0); 800 if (e == PAM_NEW_AUTHTOK_REQD) { 801 e = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK); 802 if (e != PAM_SUCCESS) { 803 syslog(LOG_ERR, "pam_chauthtok: %s", 804 pam_strerror(pamh, e)); 805 rval = 1; 806 } 807 } else if (e != PAM_SUCCESS) { 808 rval = 1; 809 } 810 } 811 812 if (rval != 0) { 813 if ((e = pam_end(pamh, e)) != PAM_SUCCESS) { 814 syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e)); 815 } 816 pamh = NULL; 817 } 818 return rval; 819} 820 821static int 822export_pam_environment() 823{ 824 char **pp; 825 826 for (pp = environ_pam; *pp != NULL; pp++) { 827 if (ok_to_export(*pp)) 828 (void) putenv(*pp); 829 free(*pp); 830 } 831 return PAM_SUCCESS; 832} 833 834/* 835 * Sanity checks on PAM environmental variables: 836 * - Make sure there is an '=' in the string. 837 * - Make sure the string doesn't run on too long. 838 * - Do not export certain variables. This list was taken from the 839 * Solaris pam_putenv(3) man page. 840 */ 841static int 842ok_to_export(s) 843 const char *s; 844{ 845 static const char *noexport[] = { 846 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 847 "IFS", "PATH", NULL 848 }; 849 const char **pp; 850 size_t n; 851 852 if (strlen(s) > 1024 || strchr(s, '=') == NULL) 853 return 0; 854 if (strncmp(s, "LD_", 3) == 0) 855 return 0; 856 for (pp = noexport; *pp != NULL; pp++) { 857 n = strlen(*pp); 858 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 859 return 0; 860 } 861 return 1; 862} 863 864static void 865usage() 866{ 867 868 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 869 exit(1); 870} 871 872/* 873 * Allow for authentication style and/or kerberos instance 874 */ 875 876#define NBUFSIZ UT_NAMESIZE + 64 877 878void 879getloginname() 880{ 881 int ch; 882 char *p; 883 static char nbuf[NBUFSIZ]; 884 885 for (;;) { 886 (void)printf("%s", prompt); 887 for (p = nbuf; (ch = getchar()) != '\n'; ) { 888 if (ch == EOF) { 889 badlogin(username); 890 exit(0); 891 } 892 if (p < nbuf + (NBUFSIZ - 1)) 893 *p++ = ch; 894 } 895 if (p > nbuf) { 896 if (nbuf[0] == '-') 897 (void)fprintf(stderr, 898 "login names may not start with '-'.\n"); 899 else { 900 *p = '\0'; 901 username = nbuf; 902 break; 903 } 904 } 905 } 906} 907 908int 909rootterm(ttyn) 910 char *ttyn; 911{ 912 struct ttyent *t; 913 914 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE); 915} 916 917volatile int motdinterrupt; 918 919void 920sigint(signo) 921 int signo __unused; 922{ 923 motdinterrupt = 1; 924} 925 926void 927motd(motdfile) 928 char *motdfile; 929{ 930 int fd, nchars; 931 sig_t oldint; 932 char tbuf[256]; 933 934 if ((fd = open(motdfile, O_RDONLY, 0)) < 0) 935 return; 936 motdinterrupt = 0; 937 oldint = signal(SIGINT, sigint); 938 while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0 && !motdinterrupt) 939 (void)write(fileno(stdout), tbuf, nchars); 940 (void)signal(SIGINT, oldint); 941 (void)close(fd); 942} 943 944/* ARGSUSED */ 945void 946timedout(signo) 947 int signo; 948{ 949 950 longjmp(timeout_buf, signo); 951} 952 953 954void 955dolastlog(quiet) 956 int quiet; 957{ 958 struct lastlog ll; 959 int fd; 960 961 if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) { 962 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 963 if (!quiet) { 964 if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) && 965 ll.ll_time != 0) { 966 (void)printf("Last login: %.*s ", 967 24-5, (char *)ctime(&ll.ll_time)); 968 if (*ll.ll_host != '\0') 969 (void)printf("from %.*s\n", 970 (int)sizeof(ll.ll_host), 971 ll.ll_host); 972 else 973 (void)printf("on %.*s\n", 974 (int)sizeof(ll.ll_line), 975 ll.ll_line); 976 } 977 (void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET); 978 } 979 memset((void *)&ll, 0, sizeof(ll)); 980 (void)time(&ll.ll_time); 981 (void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line)); 982 if (hostname) 983 (void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host)); 984 (void)write(fd, (char *)&ll, sizeof(ll)); 985 (void)close(fd); 986 } else { 987 syslog(LOG_ERR, "cannot open %s: %m", _PATH_LASTLOG); 988 } 989} 990 991void 992badlogin(name) 993 char *name; 994{ 995 996 if (failures == 0) 997 return; 998 if (hostname) { 999 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 1000 failures, failures > 1 ? "S" : "", full_hostname); 1001 syslog(LOG_AUTHPRIV|LOG_NOTICE, 1002 "%d LOGIN FAILURE%s FROM %s, %s", 1003 failures, failures > 1 ? "S" : "", full_hostname, name); 1004 } else { 1005 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 1006 failures, failures > 1 ? "S" : "", tty); 1007 syslog(LOG_AUTHPRIV|LOG_NOTICE, 1008 "%d LOGIN FAILURE%s ON %s, %s", 1009 failures, failures > 1 ? "S" : "", tty, name); 1010 } 1011 failures = 0; 1012} 1013 1014#undef UNKNOWN 1015#define UNKNOWN "su" 1016 1017char * 1018stypeof(ttyid) 1019 char *ttyid; 1020{ 1021 struct ttyent *t; 1022 1023 if (ttyid != NULL && *ttyid != '\0') { 1024 t = getttynam(ttyid); 1025 if (t != NULL && t->ty_type != NULL) 1026 return (t->ty_type); 1027 } 1028 return (UNKNOWN); 1029} 1030 1031void 1032refused(msg, rtype, lout) 1033 char *msg; 1034 char *rtype; 1035 int lout; 1036{ 1037 1038 if (msg != NULL) 1039 printf("%s.\n", msg); 1040 if (hostname) 1041 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 1042 pwd->pw_name, rtype, full_hostname, tty); 1043 else 1044 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 1045 pwd->pw_name, rtype, tty); 1046 if (lout) 1047 sleepexit(1); 1048} 1049 1050void 1051sleepexit(eval) 1052 int eval; 1053{ 1054 1055 (void)sleep(5); 1056 exit(eval); 1057} 1058