1 /*- 2 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * Copyright (c) 2002 Networks Associates Technologies, Inc. 5 * All rights reserved. 6 * 7 * Portions of this software were developed for the FreeBSD Project by 8 * ThinkSec AS and NAI Labs, the Security Research Division of Network 9 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 10 * ("CBOSS"), as part of the DARPA CHATS research program. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 */ 40 41 #if 0 42 #ifndef lint 43 static char sccsid[] = "@(#)login.c 8.4 (Berkeley) 4/2/94"; 44 #endif 45 #endif 46 47 #include <sys/cdefs.h> 48 __FBSDID("$FreeBSD$"); 49 50 /* 51 * login [ name ] 52 * login -h hostname (for telnetd, etc.) 53 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 54 */ 55 56 #include <sys/param.h> 57 #include <sys/file.h> 58 #include <sys/stat.h> 59 #include <sys/time.h> 60 #include <sys/resource.h> 61 #include <sys/wait.h> 62 63 #include <err.h> 64 #include <errno.h> 65 #include <grp.h> 66 #include <libutil.h> 67 #include <login_cap.h> 68 #include <pwd.h> 69 #include <setjmp.h> 70 #include <signal.h> 71 #include <stdio.h> 72 #include <stdlib.h> 73 #include <string.h> 74 #include <syslog.h> 75 #include <ttyent.h> 76 #include <unistd.h> 77 78 #include <security/pam_appl.h> 79 #include <security/openpam.h> 80 81 #include "login.h" 82 #include "pathnames.h" 83 84 static int auth_pam(void); 85 static void bail(int, int); 86 static int export(const char *); 87 static void export_pam_environment(void); 88 static int motd(const char *); 89 static void badlogin(char *); 90 static char *getloginname(void); 91 static void pam_syslog(const char *); 92 static void pam_cleanup(void); 93 static void refused(const char *, const char *, int); 94 static const char *stypeof(char *); 95 static void sigint(int); 96 static void timedout(int); 97 static void usage(void); 98 99 #define TTYGRPNAME "tty" /* group to own ttys */ 100 #define DEFAULT_BACKOFF 3 101 #define DEFAULT_RETRIES 10 102 #define DEFAULT_PROMPT "login: " 103 #define DEFAULT_PASSWD_PROMPT "Password:" 104 #define TERM_UNKNOWN "su" 105 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 106 #define NO_SLEEP_EXIT 0 107 #define SLEEP_EXIT 5 108 109 /* 110 * This bounds the time given to login. Not a define so it can 111 * be patched on machines where it's too small. 112 */ 113 static u_int timeout = 300; 114 115 /* Buffer for signal handling of timeout */ 116 static jmp_buf timeout_buf; 117 118 struct passwd *pwd; 119 static int failures; 120 121 static char *envinit[1]; /* empty environment list */ 122 123 /* 124 * Command line flags and arguments 125 */ 126 static int fflag; /* -f: do not perform authentication */ 127 static int hflag; /* -h: login from remote host */ 128 static char *hostname; /* hostname from command line */ 129 static int pflag; /* -p: preserve environment */ 130 131 /* 132 * User name 133 */ 134 static char *username; /* user name */ 135 static char *olduser; /* previous user name */ 136 137 /* 138 * Prompts 139 */ 140 static char default_prompt[] = DEFAULT_PROMPT; 141 static const char *prompt; 142 static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT; 143 static const char *passwd_prompt; 144 145 static char *tty; 146 147 /* 148 * PAM data 149 */ 150 static pam_handle_t *pamh = NULL; 151 static struct pam_conv pamc = { openpam_ttyconv, NULL }; 152 static int pam_err; 153 static int pam_silent = PAM_SILENT; 154 static int pam_cred_established; 155 static int pam_session_established; 156 157 int 158 main(int argc, char *argv[]) 159 { 160 struct group *gr; 161 struct stat st; 162 int retries, backoff; 163 int ask, ch, cnt, quietlog, rootlogin, rval; 164 uid_t uid, euid; 165 gid_t egid; 166 char *term; 167 char *p, *ttyn; 168 char tname[sizeof(_PATH_TTY) + 10]; 169 char *arg0; 170 const char *tp; 171 const char *shell = NULL; 172 login_cap_t *lc = NULL; 173 login_cap_t *lc_user = NULL; 174 pid_t pid; 175 #ifdef USE_BSM_AUDIT 176 char auditsuccess = 1; 177 #endif 178 179 (void)signal(SIGQUIT, SIG_IGN); 180 (void)signal(SIGINT, SIG_IGN); 181 (void)signal(SIGHUP, SIG_IGN); 182 if (setjmp(timeout_buf)) { 183 if (failures) 184 badlogin(username); 185 (void)fprintf(stderr, "Login timed out after %d seconds\n", 186 timeout); 187 bail(NO_SLEEP_EXIT, 0); 188 } 189 (void)signal(SIGALRM, timedout); 190 (void)alarm(timeout); 191 (void)setpriority(PRIO_PROCESS, 0, 0); 192 193 openlog("login", LOG_ODELAY, LOG_AUTH); 194 195 uid = getuid(); 196 euid = geteuid(); 197 egid = getegid(); 198 199 while ((ch = getopt(argc, argv, "fh:p")) != -1) 200 switch (ch) { 201 case 'f': 202 fflag = 1; 203 break; 204 case 'h': 205 if (uid != 0) 206 errx(1, "-h option: %s", strerror(EPERM)); 207 if (strlen(optarg) >= MAXHOSTNAMELEN) 208 errx(1, "-h option: %s: exceeds maximum " 209 "hostname size", optarg); 210 hflag = 1; 211 hostname = optarg; 212 break; 213 case 'p': 214 pflag = 1; 215 break; 216 case '?': 217 default: 218 if (uid == 0) 219 syslog(LOG_ERR, "invalid flag %c", ch); 220 usage(); 221 } 222 argc -= optind; 223 argv += optind; 224 225 if (argc > 0) { 226 username = strdup(*argv); 227 if (username == NULL) 228 err(1, "strdup()"); 229 ask = 0; 230 } else { 231 ask = 1; 232 } 233 234 setproctitle("-%s", getprogname()); 235 236 closefrom(3); 237 238 /* 239 * Get current TTY 240 */ 241 ttyn = ttyname(STDIN_FILENO); 242 if (ttyn == NULL || *ttyn == '\0') { 243 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 244 ttyn = tname; 245 } 246 if (strncmp(ttyn, _PATH_DEV, sizeof _PATH_DEV - 1) == 0) 247 tty = ttyn + sizeof _PATH_DEV - 1; 248 else 249 tty = ttyn; 250 251 /* 252 * Get "login-retries" & "login-backoff" from default class 253 */ 254 lc = login_getclass(NULL); 255 prompt = login_getcapstr(lc, "login_prompt", 256 default_prompt, default_prompt); 257 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 258 default_passwd_prompt, default_passwd_prompt); 259 retries = login_getcapnum(lc, "login-retries", 260 DEFAULT_RETRIES, DEFAULT_RETRIES); 261 backoff = login_getcapnum(lc, "login-backoff", 262 DEFAULT_BACKOFF, DEFAULT_BACKOFF); 263 login_close(lc); 264 lc = NULL; 265 266 /* 267 * Try to authenticate the user until we succeed or time out. 268 */ 269 for (cnt = 0;; ask = 1) { 270 if (ask) { 271 fflag = 0; 272 if (olduser != NULL) 273 free(olduser); 274 olduser = username; 275 username = getloginname(); 276 } 277 rootlogin = 0; 278 279 /* 280 * Note if trying multiple user names; log failures for 281 * previous user name, but don't bother logging one failure 282 * for nonexistent name (mistyped username). 283 */ 284 if (failures && strcmp(olduser, username) != 0) { 285 if (failures > (pwd ? 0 : 1)) 286 badlogin(olduser); 287 } 288 289 /* 290 * Load the PAM policy and set some variables 291 */ 292 pam_err = pam_start("login", username, &pamc, &pamh); 293 if (pam_err != PAM_SUCCESS) { 294 pam_syslog("pam_start()"); 295 #ifdef USE_BSM_AUDIT 296 au_login_fail("PAM Error", 1); 297 #endif 298 bail(NO_SLEEP_EXIT, 1); 299 } 300 pam_err = pam_set_item(pamh, PAM_TTY, tty); 301 if (pam_err != PAM_SUCCESS) { 302 pam_syslog("pam_set_item(PAM_TTY)"); 303 #ifdef USE_BSM_AUDIT 304 au_login_fail("PAM Error", 1); 305 #endif 306 bail(NO_SLEEP_EXIT, 1); 307 } 308 pam_err = pam_set_item(pamh, PAM_RHOST, hostname); 309 if (pam_err != PAM_SUCCESS) { 310 pam_syslog("pam_set_item(PAM_RHOST)"); 311 #ifdef USE_BSM_AUDIT 312 au_login_fail("PAM Error", 1); 313 #endif 314 bail(NO_SLEEP_EXIT, 1); 315 } 316 317 pwd = getpwnam(username); 318 if (pwd != NULL && pwd->pw_uid == 0) 319 rootlogin = 1; 320 321 /* 322 * If the -f option was specified and the caller is 323 * root or the caller isn't changing their uid, don't 324 * authenticate. 325 */ 326 if (pwd != NULL && fflag && 327 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) { 328 /* already authenticated */ 329 rval = 0; 330 #ifdef USE_BSM_AUDIT 331 auditsuccess = 0; /* opened a terminal window only */ 332 #endif 333 } else { 334 fflag = 0; 335 (void)setpriority(PRIO_PROCESS, 0, -4); 336 rval = auth_pam(); 337 (void)setpriority(PRIO_PROCESS, 0, 0); 338 } 339 340 if (pwd && rval == 0) 341 break; 342 343 pam_cleanup(); 344 345 /* 346 * We are not exiting here, but this corresponds to a failed 347 * login event, so set exitstatus to 1. 348 */ 349 #ifdef USE_BSM_AUDIT 350 au_login_fail("Login incorrect", 1); 351 #endif 352 353 (void)printf("Login incorrect\n"); 354 failures++; 355 356 pwd = NULL; 357 358 /* 359 * Allow up to 'retry' (10) attempts, but start 360 * backing off after 'backoff' (3) attempts. 361 */ 362 if (++cnt > backoff) { 363 if (cnt >= retries) { 364 badlogin(username); 365 bail(SLEEP_EXIT, 1); 366 } 367 sleep((u_int)((cnt - backoff) * 5)); 368 } 369 } 370 371 /* committed to login -- turn off timeout */ 372 (void)alarm((u_int)0); 373 (void)signal(SIGHUP, SIG_DFL); 374 375 endpwent(); 376 377 #ifdef USE_BSM_AUDIT 378 /* Audit successful login. */ 379 if (auditsuccess) 380 au_login_success(); 381 #endif 382 383 /* 384 * Establish the login class. 385 */ 386 lc = login_getpwclass(pwd); 387 lc_user = login_getuserclass(pwd); 388 389 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0))) 390 quietlog = login_getcapbool(lc, "hushlogin", 0); 391 392 /* 393 * Switching needed for NFS with root access disabled. 394 * 395 * XXX: This change fails to modify the additional groups for the 396 * process, and as such, may restrict rights normally granted 397 * through those groups. 398 */ 399 (void)setegid(pwd->pw_gid); 400 (void)seteuid(rootlogin ? 0 : pwd->pw_uid); 401 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 402 if (login_getcapbool(lc, "requirehome", 0)) 403 refused("Home directory not available", "HOMEDIR", 1); 404 if (chdir("/") < 0) 405 refused("Cannot find root directory", "ROOTDIR", 1); 406 if (!quietlog || *pwd->pw_dir) 407 printf("No home directory.\nLogging in with home = \"/\".\n"); 408 pwd->pw_dir = strdup("/"); 409 if (pwd->pw_dir == NULL) { 410 syslog(LOG_NOTICE, "strdup(): %m"); 411 bail(SLEEP_EXIT, 1); 412 } 413 } 414 (void)seteuid(euid); 415 (void)setegid(egid); 416 if (!quietlog) { 417 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 418 if (!quietlog) 419 pam_silent = 0; 420 } 421 422 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 423 if (*pwd->pw_shell == '\0') 424 pwd->pw_shell = strdup(_PATH_BSHELL); 425 if (pwd->pw_shell == NULL) { 426 syslog(LOG_NOTICE, "strdup(): %m"); 427 bail(SLEEP_EXIT, 1); 428 } 429 if (*shell == '\0') /* Not overridden */ 430 shell = pwd->pw_shell; 431 if ((shell = strdup(shell)) == NULL) { 432 syslog(LOG_NOTICE, "strdup(): %m"); 433 bail(SLEEP_EXIT, 1); 434 } 435 436 /* 437 * Set device protections, depending on what terminal the 438 * user is logged in. This feature is used on Suns to give 439 * console users better privacy. 440 */ 441 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 442 443 /* 444 * Clear flags of the tty. None should be set, and when the 445 * user sets them otherwise, this can cause the chown to fail. 446 * Since it isn't clear that flags are useful on character 447 * devices, we just clear them. 448 * 449 * We don't log in the case of EOPNOTSUPP because dev might be 450 * on NFS, which doesn't support chflags. 451 * 452 * We don't log in the EROFS because that means that /dev is on 453 * a read only file system and we assume that the permissions there 454 * are sane. 455 */ 456 if (ttyn != tname && chflags(ttyn, 0)) 457 if (errno != EOPNOTSUPP && errno != EROFS) 458 syslog(LOG_ERR, "chflags(%s): %m", ttyn); 459 if (ttyn != tname && chown(ttyn, pwd->pw_uid, 460 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 461 if (errno != EROFS) 462 syslog(LOG_ERR, "chown(%s): %m", ttyn); 463 464 /* 465 * Exclude cons/vt/ptys only, assume dialup otherwise 466 * TODO: Make dialup tty determination a library call 467 * for consistency (finger etc.) 468 */ 469 if (hflag && isdialuptty(tty)) 470 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 471 472 #ifdef LOGALL 473 /* 474 * Syslog each successful login, so we don't have to watch 475 * hundreds of wtmp or lastlogin files. 476 */ 477 if (hflag) 478 syslog(LOG_INFO, "login from %s on %s as %s", 479 hostname, tty, pwd->pw_name); 480 else 481 syslog(LOG_INFO, "login on %s as %s", 482 tty, pwd->pw_name); 483 #endif 484 485 /* 486 * If fflag is on, assume caller/authenticator has logged root 487 * login. 488 */ 489 if (rootlogin && fflag == 0) { 490 if (hflag) 491 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 492 username, tty, hostname); 493 else 494 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 495 username, tty); 496 } 497 498 /* 499 * Destroy environment unless user has requested its 500 * preservation - but preserve TERM in all cases 501 */ 502 term = getenv("TERM"); 503 if (!pflag) 504 environ = envinit; 505 if (term != NULL) 506 setenv("TERM", term, 0); 507 508 /* 509 * PAM modules might add supplementary groups during pam_setcred(). 510 */ 511 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 512 syslog(LOG_ERR, "setusercontext() failed - exiting"); 513 bail(NO_SLEEP_EXIT, 1); 514 } 515 516 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED); 517 if (pam_err != PAM_SUCCESS) { 518 pam_syslog("pam_setcred()"); 519 bail(NO_SLEEP_EXIT, 1); 520 } 521 pam_cred_established = 1; 522 523 pam_err = pam_open_session(pamh, pam_silent); 524 if (pam_err != PAM_SUCCESS) { 525 pam_syslog("pam_open_session()"); 526 bail(NO_SLEEP_EXIT, 1); 527 } 528 pam_session_established = 1; 529 530 /* 531 * We must fork() before setuid() because we need to call 532 * pam_close_session() as root. 533 */ 534 pid = fork(); 535 if (pid < 0) { 536 err(1, "fork"); 537 } else if (pid != 0) { 538 /* 539 * Parent: wait for child to finish, then clean up 540 * session. 541 */ 542 int status; 543 setproctitle("-%s [pam]", getprogname()); 544 waitpid(pid, &status, 0); 545 bail(NO_SLEEP_EXIT, 0); 546 } 547 548 /* 549 * NOTICE: We are now in the child process! 550 */ 551 552 /* 553 * Add any environment variables the PAM modules may have set. 554 */ 555 export_pam_environment(); 556 557 /* 558 * We're done with PAM now; our parent will deal with the rest. 559 */ 560 pam_end(pamh, 0); 561 pamh = NULL; 562 563 /* 564 * We don't need to be root anymore, so set the login name and 565 * the UID. 566 */ 567 if (setlogin(username) != 0) { 568 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 569 bail(NO_SLEEP_EXIT, 1); 570 } 571 if (setusercontext(lc, pwd, pwd->pw_uid, 572 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 573 syslog(LOG_ERR, "setusercontext() failed - exiting"); 574 exit(1); 575 } 576 577 (void)setenv("SHELL", pwd->pw_shell, 1); 578 (void)setenv("HOME", pwd->pw_dir, 1); 579 /* Overwrite "term" from login.conf(5) for any known TERM */ 580 if (term == NULL && (tp = stypeof(tty)) != NULL) 581 (void)setenv("TERM", tp, 1); 582 else 583 (void)setenv("TERM", TERM_UNKNOWN, 0); 584 (void)setenv("LOGNAME", username, 1); 585 (void)setenv("USER", username, 1); 586 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0); 587 588 if (!quietlog) { 589 const char *cw; 590 591 cw = login_getcapstr(lc, "welcome", NULL, NULL); 592 if (cw != NULL && access(cw, F_OK) == 0) 593 motd(cw); 594 else 595 motd(_PATH_MOTDFILE); 596 597 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 && 598 login_getcapbool(lc, "nocheckmail", 0) == 0) { 599 char *cx; 600 601 /* $MAIL may have been set by class. */ 602 cx = getenv("MAIL"); 603 if (cx == NULL) { 604 asprintf(&cx, "%s/%s", 605 _PATH_MAILDIR, pwd->pw_name); 606 } 607 if (cx && stat(cx, &st) == 0 && st.st_size != 0) 608 (void)printf("You have %smail.\n", 609 (st.st_mtime > st.st_atime) ? "new " : ""); 610 if (getenv("MAIL") == NULL) 611 free(cx); 612 } 613 } 614 615 login_close(lc_user); 616 login_close(lc); 617 618 (void)signal(SIGALRM, SIG_DFL); 619 (void)signal(SIGQUIT, SIG_DFL); 620 (void)signal(SIGINT, SIG_DFL); 621 (void)signal(SIGTSTP, SIG_IGN); 622 623 /* 624 * Login shells have a leading '-' in front of argv[0] 625 */ 626 p = strrchr(pwd->pw_shell, '/'); 627 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) { 628 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 629 username); 630 errx(1, "shell exceeds maximum pathname size"); 631 } else if (arg0 == NULL) { 632 err(1, "asprintf()"); 633 } 634 635 execlp(shell, arg0, (char *)0); 636 err(1, "%s", shell); 637 638 /* 639 * That's it, folks! 640 */ 641 } 642 643 /* 644 * Attempt to authenticate the user using PAM. Returns 0 if the user is 645 * authenticated, or 1 if not authenticated. If some sort of PAM system 646 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 647 * function returns -1. This can be used as an indication that we should 648 * fall back to a different authentication mechanism. 649 */ 650 static int 651 auth_pam(void) 652 { 653 const char *tmpl_user; 654 const void *item; 655 int rval; 656 657 pam_err = pam_authenticate(pamh, pam_silent); 658 switch (pam_err) { 659 660 case PAM_SUCCESS: 661 /* 662 * With PAM we support the concept of a "template" 663 * user. The user enters a login name which is 664 * authenticated by PAM, usually via a remote service 665 * such as RADIUS or TACACS+. If authentication 666 * succeeds, a different but related "template" name 667 * is used for setting the credentials, shell, and 668 * home directory. The name the user enters need only 669 * exist on the remote authentication server, but the 670 * template name must be present in the local password 671 * database. 672 * 673 * This is supported by two various mechanisms in the 674 * individual modules. However, from the application's 675 * point of view, the template user is always passed 676 * back as a changed value of the PAM_USER item. 677 */ 678 pam_err = pam_get_item(pamh, PAM_USER, &item); 679 if (pam_err == PAM_SUCCESS) { 680 tmpl_user = (const char *)item; 681 if (strcmp(username, tmpl_user) != 0) 682 pwd = getpwnam(tmpl_user); 683 } else { 684 pam_syslog("pam_get_item(PAM_USER)"); 685 } 686 rval = 0; 687 break; 688 689 case PAM_AUTH_ERR: 690 case PAM_USER_UNKNOWN: 691 case PAM_MAXTRIES: 692 rval = 1; 693 break; 694 695 default: 696 pam_syslog("pam_authenticate()"); 697 rval = -1; 698 break; 699 } 700 701 if (rval == 0) { 702 pam_err = pam_acct_mgmt(pamh, pam_silent); 703 switch (pam_err) { 704 case PAM_SUCCESS: 705 break; 706 case PAM_NEW_AUTHTOK_REQD: 707 pam_err = pam_chauthtok(pamh, 708 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK); 709 if (pam_err != PAM_SUCCESS) { 710 pam_syslog("pam_chauthtok()"); 711 rval = 1; 712 } 713 break; 714 default: 715 pam_syslog("pam_acct_mgmt()"); 716 rval = 1; 717 break; 718 } 719 } 720 721 if (rval != 0) { 722 pam_end(pamh, pam_err); 723 pamh = NULL; 724 } 725 return (rval); 726 } 727 728 /* 729 * Export any environment variables PAM modules may have set 730 */ 731 static void 732 export_pam_environment(void) 733 { 734 char **pam_env; 735 char **pp; 736 737 pam_env = pam_getenvlist(pamh); 738 if (pam_env != NULL) { 739 for (pp = pam_env; *pp != NULL; pp++) { 740 (void)export(*pp); 741 free(*pp); 742 } 743 } 744 } 745 746 /* 747 * Perform sanity checks on an environment variable: 748 * - Make sure there is an '=' in the string. 749 * - Make sure the string doesn't run on too long. 750 * - Do not export certain variables. This list was taken from the 751 * Solaris pam_putenv(3) man page. 752 * Then export it. 753 */ 754 static int 755 export(const char *s) 756 { 757 static const char *noexport[] = { 758 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 759 "IFS", "PATH", NULL 760 }; 761 char *p; 762 const char **pp; 763 size_t n; 764 765 if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL) 766 return (0); 767 if (strncmp(s, "LD_", 3) == 0) 768 return (0); 769 for (pp = noexport; *pp != NULL; pp++) { 770 n = strlen(*pp); 771 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 772 return (0); 773 } 774 *p = '\0'; 775 (void)setenv(s, p + 1, 1); 776 *p = '='; 777 return (1); 778 } 779 780 static void 781 usage(void) 782 { 783 784 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 785 exit(1); 786 } 787 788 /* 789 * Prompt user and read login name from stdin. 790 */ 791 static char * 792 getloginname(void) 793 { 794 char *nbuf, *p; 795 int ch; 796 797 nbuf = malloc(MAXLOGNAME); 798 if (nbuf == NULL) 799 err(1, "malloc()"); 800 do { 801 (void)printf("%s", prompt); 802 for (p = nbuf; (ch = getchar()) != '\n'; ) { 803 if (ch == EOF) { 804 badlogin(username); 805 bail(NO_SLEEP_EXIT, 0); 806 } 807 if (p < nbuf + MAXLOGNAME - 1) 808 *p++ = ch; 809 } 810 } while (p == nbuf); 811 812 *p = '\0'; 813 if (nbuf[0] == '-') { 814 pam_silent = 0; 815 memmove(nbuf, nbuf + 1, strlen(nbuf)); 816 } else { 817 pam_silent = PAM_SILENT; 818 } 819 return nbuf; 820 } 821 822 /* 823 * SIGINT handler for motd(). 824 */ 825 static volatile int motdinterrupt; 826 static void 827 sigint(int signo __unused) 828 { 829 motdinterrupt = 1; 830 } 831 832 /* 833 * Display the contents of a file (such as /etc/motd). 834 */ 835 static int 836 motd(const char *motdfile) 837 { 838 sig_t oldint; 839 FILE *f; 840 int ch; 841 842 if ((f = fopen(motdfile, "r")) == NULL) 843 return (-1); 844 motdinterrupt = 0; 845 oldint = signal(SIGINT, sigint); 846 while ((ch = fgetc(f)) != EOF && !motdinterrupt) 847 putchar(ch); 848 signal(SIGINT, oldint); 849 if (ch != EOF || ferror(f)) { 850 fclose(f); 851 return (-1); 852 } 853 fclose(f); 854 return (0); 855 } 856 857 /* 858 * SIGALRM handler, to enforce login prompt timeout. 859 * 860 * XXX This can potentially confuse the hell out of PAM. We should 861 * XXX instead implement a conversation function that returns 862 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal 863 * XXX handler just set a flag. 864 */ 865 static void 866 timedout(int signo __unused) 867 { 868 869 longjmp(timeout_buf, signo); 870 } 871 872 static void 873 badlogin(char *name) 874 { 875 876 if (failures == 0) 877 return; 878 if (hflag) { 879 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 880 failures, failures > 1 ? "S" : "", hostname); 881 syslog(LOG_AUTHPRIV|LOG_NOTICE, 882 "%d LOGIN FAILURE%s FROM %s, %s", 883 failures, failures > 1 ? "S" : "", hostname, name); 884 } else { 885 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 886 failures, failures > 1 ? "S" : "", tty); 887 syslog(LOG_AUTHPRIV|LOG_NOTICE, 888 "%d LOGIN FAILURE%s ON %s, %s", 889 failures, failures > 1 ? "S" : "", tty, name); 890 } 891 failures = 0; 892 } 893 894 const char * 895 stypeof(char *ttyid) 896 { 897 struct ttyent *t; 898 899 if (ttyid != NULL && *ttyid != '\0') { 900 t = getttynam(ttyid); 901 if (t != NULL && t->ty_type != NULL) 902 return (t->ty_type); 903 } 904 return (NULL); 905 } 906 907 static void 908 refused(const char *msg, const char *rtype, int lout) 909 { 910 911 if (msg != NULL) 912 printf("%s.\n", msg); 913 if (hflag) 914 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 915 pwd->pw_name, rtype, hostname, tty); 916 else 917 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 918 pwd->pw_name, rtype, tty); 919 if (lout) 920 bail(SLEEP_EXIT, 1); 921 } 922 923 /* 924 * Log a PAM error 925 */ 926 static void 927 pam_syslog(const char *msg) 928 { 929 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err)); 930 } 931 932 /* 933 * Shut down PAM 934 */ 935 static void 936 pam_cleanup(void) 937 { 938 939 if (pamh != NULL) { 940 if (pam_session_established) { 941 pam_err = pam_close_session(pamh, 0); 942 if (pam_err != PAM_SUCCESS) 943 pam_syslog("pam_close_session()"); 944 } 945 pam_session_established = 0; 946 if (pam_cred_established) { 947 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED); 948 if (pam_err != PAM_SUCCESS) 949 pam_syslog("pam_setcred()"); 950 } 951 pam_cred_established = 0; 952 pam_end(pamh, pam_err); 953 pamh = NULL; 954 } 955 } 956 957 /* 958 * Exit, optionally after sleeping a few seconds 959 */ 960 void 961 bail(int sec, int eval) 962 { 963 964 pam_cleanup(); 965 #ifdef USE_BSM_AUDIT 966 if (pwd != NULL) 967 audit_logout(); 968 #endif 969 (void)sleep(sec); 970 exit(eval); 971 } 972