1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * Copyright (c) 2002 Networks Associates Technologies, Inc. 7 * All rights reserved. 8 * 9 * Portions of this software were developed for the FreeBSD Project by 10 * ThinkSec AS and NAI Labs, the Security Research Division of Network 11 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 12 * ("CBOSS"), as part of the DARPA CHATS research program. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. All advertising materials mentioning features or use of this software 23 * must display the following acknowledgement: 24 * This product includes software developed by the University of 25 * California, Berkeley and its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 #if 0 44 #endif 45 46 #include <sys/cdefs.h> 47 /* 48 * login [ name ] 49 * login -h hostname (for telnetd, etc.) 50 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 51 */ 52 53 #include <sys/param.h> 54 #include <sys/file.h> 55 #include <sys/stat.h> 56 #include <sys/time.h> 57 #include <sys/resource.h> 58 #include <sys/wait.h> 59 60 #include <err.h> 61 #include <errno.h> 62 #include <grp.h> 63 #include <login_cap.h> 64 #include <pwd.h> 65 #include <setjmp.h> 66 #include <signal.h> 67 #include <stdio.h> 68 #include <stdlib.h> 69 #include <string.h> 70 #include <syslog.h> 71 #include <ttyent.h> 72 #include <unistd.h> 73 74 #include <security/pam_appl.h> 75 #include <security/openpam.h> 76 77 #include "login.h" 78 #include "pathnames.h" 79 80 static int auth_pam(void); 81 static void bail(int, int); 82 static void bail_internal(int, int, int); 83 static int export(const char *); 84 static void export_pam_environment(void); 85 static int motd(const char *); 86 static void badlogin(char *); 87 static char *getloginname(void); 88 static void pam_syslog(const char *); 89 static void pam_cleanup(void); 90 static void refused(const char *, const char *, int); 91 static const char *stypeof(char *); 92 static void sigint(int); 93 static void timedout(int); 94 static void bail_sig(int); 95 static void usage(void); 96 97 #define TTYGRPNAME "tty" /* group to own ttys */ 98 #define DEFAULT_BACKOFF 3 99 #define DEFAULT_RETRIES 10 100 #define DEFAULT_PROMPT "login: " 101 #define DEFAULT_PASSWD_PROMPT "Password:" 102 #define TERM_UNKNOWN "su" 103 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 104 #define NO_SLEEP_EXIT 0 105 #define SLEEP_EXIT 5 106 107 /* 108 * This bounds the time given to login. Not a define so it can 109 * be patched on machines where it's too small. 110 */ 111 static u_int timeout = 300; 112 113 /* Buffer for signal handling of timeout */ 114 static jmp_buf timeout_buf; 115 116 struct passwd *pwd; 117 static int failures; 118 119 static char *envinit[1]; /* empty environment list */ 120 121 /* 122 * Command line flags and arguments 123 */ 124 static int fflag; /* -f: do not perform authentication */ 125 static int hflag; /* -h: login from remote host */ 126 static char *hostname; /* hostname from command line */ 127 static int pflag; /* -p: preserve environment */ 128 129 /* 130 * User name 131 */ 132 static char *username; /* user name */ 133 static char *olduser; /* previous user name */ 134 135 /* 136 * Prompts 137 */ 138 static char default_prompt[] = DEFAULT_PROMPT; 139 static const char *prompt; 140 static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT; 141 static const char *passwd_prompt; 142 143 static char *tty; 144 145 /* 146 * PAM data 147 */ 148 static pam_handle_t *pamh = NULL; 149 static struct pam_conv pamc = { openpam_ttyconv, NULL }; 150 static int pam_err; 151 static int pam_silent = PAM_SILENT; 152 static int pam_cred_established; 153 static int pam_session_established; 154 155 int 156 main(int argc, char *argv[]) 157 { 158 struct group *gr; 159 struct stat st; 160 int retries, backoff; 161 int ask, ch, cnt, quietlog, rootlogin, rval; 162 uid_t uid, euid; 163 gid_t egid; 164 char *term; 165 char *p, *ttyn; 166 char tname[sizeof(_PATH_TTY) + 10]; 167 char *arg0; 168 const char *tp; 169 const char *shell = NULL; 170 login_cap_t *lc = NULL; 171 login_cap_t *lc_user = NULL; 172 pid_t pid; 173 sigset_t mask, omask; 174 struct sigaction sa; 175 #ifdef USE_BSM_AUDIT 176 char auditsuccess = 1; 177 #endif 178 179 sa.sa_flags = SA_RESTART; 180 (void)sigfillset(&sa.sa_mask); 181 sa.sa_handler = SIG_IGN; 182 (void)sigaction(SIGQUIT, &sa, NULL); 183 (void)sigaction(SIGINT, &sa, NULL); 184 (void)sigaction(SIGHUP, &sa, NULL); 185 if (setjmp(timeout_buf)) { 186 if (failures) 187 badlogin(username); 188 (void)fprintf(stderr, "Login timed out after %d seconds\n", 189 timeout); 190 bail(NO_SLEEP_EXIT, 0); 191 } 192 sa.sa_handler = timedout; 193 (void)sigaction(SIGALRM, &sa, NULL); 194 (void)alarm(timeout); 195 (void)setpriority(PRIO_PROCESS, 0, 0); 196 197 openlog("login", LOG_CONS, LOG_AUTH); 198 199 uid = getuid(); 200 euid = geteuid(); 201 egid = getegid(); 202 203 while ((ch = getopt(argc, argv, "fh:p")) != -1) 204 switch (ch) { 205 case 'f': 206 fflag = 1; 207 break; 208 case 'h': 209 if (uid != 0) 210 errx(1, "-h option: %s", strerror(EPERM)); 211 if (strlen(optarg) >= MAXHOSTNAMELEN) 212 errx(1, "-h option: %s: exceeds maximum " 213 "hostname size", optarg); 214 hflag = 1; 215 hostname = optarg; 216 break; 217 case 'p': 218 pflag = 1; 219 break; 220 case '?': 221 default: 222 if (uid == 0) 223 syslog(LOG_ERR, "invalid flag %c", ch); 224 usage(); 225 } 226 argc -= optind; 227 argv += optind; 228 229 if (argc > 0) { 230 username = strdup(*argv); 231 if (username == NULL) 232 err(1, "strdup()"); 233 ask = 0; 234 } else { 235 ask = 1; 236 } 237 238 setproctitle("-%s", getprogname()); 239 240 closefrom(3); 241 242 /* 243 * Get current TTY 244 */ 245 ttyn = ttyname(STDIN_FILENO); 246 if (ttyn == NULL || *ttyn == '\0') { 247 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 248 ttyn = tname; 249 } 250 if (strncmp(ttyn, _PATH_DEV, sizeof _PATH_DEV - 1) == 0) 251 tty = ttyn + sizeof _PATH_DEV - 1; 252 else 253 tty = ttyn; 254 255 /* 256 * Get "login-retries" & "login-backoff" from default class 257 */ 258 lc = login_getclass(NULL); 259 prompt = login_getcapstr(lc, "login_prompt", 260 default_prompt, default_prompt); 261 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 262 default_passwd_prompt, default_passwd_prompt); 263 retries = login_getcapnum(lc, "login-retries", 264 DEFAULT_RETRIES, DEFAULT_RETRIES); 265 backoff = login_getcapnum(lc, "login-backoff", 266 DEFAULT_BACKOFF, DEFAULT_BACKOFF); 267 login_close(lc); 268 lc = NULL; 269 270 /* 271 * Try to authenticate the user until we succeed or time out. 272 */ 273 for (cnt = 0;; ask = 1) { 274 if (ask) { 275 fflag = 0; 276 if (olduser != NULL) 277 free(olduser); 278 olduser = username; 279 username = getloginname(); 280 } 281 rootlogin = 0; 282 283 /* 284 * Note if trying multiple user names; log failures for 285 * previous user name, but don't bother logging one failure 286 * for nonexistent name (mistyped username). 287 */ 288 if (failures && strcmp(olduser, username) != 0) { 289 if (failures > (pwd ? 0 : 1)) 290 badlogin(olduser); 291 } 292 293 /* 294 * Load the PAM policy and set some variables 295 */ 296 pam_err = pam_start("login", username, &pamc, &pamh); 297 if (pam_err != PAM_SUCCESS) { 298 pam_syslog("pam_start()"); 299 #ifdef USE_BSM_AUDIT 300 au_login_fail("PAM Error", 1); 301 #endif 302 bail(NO_SLEEP_EXIT, 1); 303 } 304 pam_err = pam_set_item(pamh, PAM_TTY, tty); 305 if (pam_err != PAM_SUCCESS) { 306 pam_syslog("pam_set_item(PAM_TTY)"); 307 #ifdef USE_BSM_AUDIT 308 au_login_fail("PAM Error", 1); 309 #endif 310 bail(NO_SLEEP_EXIT, 1); 311 } 312 pam_err = pam_set_item(pamh, PAM_RHOST, hostname); 313 if (pam_err != PAM_SUCCESS) { 314 pam_syslog("pam_set_item(PAM_RHOST)"); 315 #ifdef USE_BSM_AUDIT 316 au_login_fail("PAM Error", 1); 317 #endif 318 bail(NO_SLEEP_EXIT, 1); 319 } 320 321 pwd = getpwnam(username); 322 if (pwd != NULL && pwd->pw_uid == 0) 323 rootlogin = 1; 324 325 /* 326 * If the -f option was specified and the caller is 327 * root or the caller isn't changing their uid, don't 328 * authenticate. 329 */ 330 if (pwd != NULL && fflag && 331 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) { 332 /* already authenticated */ 333 rval = 0; 334 #ifdef USE_BSM_AUDIT 335 auditsuccess = 0; /* opened a terminal window only */ 336 #endif 337 } else { 338 fflag = 0; 339 (void)setpriority(PRIO_PROCESS, 0, -4); 340 rval = auth_pam(); 341 (void)setpriority(PRIO_PROCESS, 0, 0); 342 } 343 344 if (pwd && rval == 0) 345 break; 346 347 pam_cleanup(); 348 349 /* 350 * We are not exiting here, but this corresponds to a failed 351 * login event, so set exitstatus to 1. 352 */ 353 #ifdef USE_BSM_AUDIT 354 au_login_fail("Login incorrect", 1); 355 #endif 356 357 (void)printf("Login incorrect\n"); 358 failures++; 359 360 pwd = NULL; 361 362 /* 363 * Allow up to 'retry' (10) attempts, but start 364 * backing off after 'backoff' (3) attempts. 365 */ 366 if (++cnt > backoff) { 367 if (cnt >= retries) { 368 badlogin(username); 369 bail(SLEEP_EXIT, 1); 370 } 371 sleep((u_int)((cnt - backoff) * 5)); 372 } 373 } 374 375 /* committed to login -- turn off timeout */ 376 (void)alarm((u_int)0); 377 378 (void)sigemptyset(&mask); 379 (void)sigaddset(&mask, SIGHUP); 380 (void)sigaddset(&mask, SIGTERM); 381 (void)sigprocmask(SIG_BLOCK, &mask, &omask); 382 sa.sa_handler = bail_sig; 383 (void)sigaction(SIGHUP, &sa, NULL); 384 (void)sigaction(SIGTERM, &sa, NULL); 385 386 endpwent(); 387 388 #ifdef USE_BSM_AUDIT 389 /* Audit successful login. */ 390 if (auditsuccess) 391 au_login_success(); 392 #endif 393 394 /* 395 * This needs to happen before login_getpwclass to support 396 * home directories on GSS-API authenticated NFS where the 397 * kerberos credentials need to be saved so that the kernel 398 * can authenticate to the NFS server. 399 */ 400 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED); 401 if (pam_err != PAM_SUCCESS) { 402 pam_syslog("pam_setcred()"); 403 bail(NO_SLEEP_EXIT, 1); 404 } 405 pam_cred_established = 1; 406 407 /* 408 * Establish the login class. 409 */ 410 lc = login_getpwclass(pwd); 411 lc_user = login_getuserclass(pwd); 412 413 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0))) 414 quietlog = login_getcapbool(lc, "hushlogin", 0); 415 416 /* 417 * Switching needed for NFS with root access disabled. 418 * 419 * XXX: This change fails to modify the additional groups for the 420 * process, and as such, may restrict rights normally granted 421 * through those groups. 422 */ 423 (void)setegid(pwd->pw_gid); 424 (void)seteuid(rootlogin ? 0 : pwd->pw_uid); 425 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 426 if (login_getcapbool(lc, "requirehome", 0)) 427 refused("Home directory not available", "HOMEDIR", 1); 428 if (chdir("/") < 0) 429 refused("Cannot find root directory", "ROOTDIR", 1); 430 if (!quietlog || *pwd->pw_dir) 431 printf("No home directory.\nLogging in with home = \"/\".\n"); 432 pwd->pw_dir = strdup("/"); 433 if (pwd->pw_dir == NULL) { 434 syslog(LOG_NOTICE, "strdup(): %m"); 435 bail(SLEEP_EXIT, 1); 436 } 437 } 438 (void)seteuid(euid); 439 (void)setegid(egid); 440 if (!quietlog) { 441 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 442 if (!quietlog) 443 pam_silent = 0; 444 } 445 446 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 447 if (*pwd->pw_shell == '\0') 448 pwd->pw_shell = strdup(_PATH_BSHELL); 449 if (pwd->pw_shell == NULL) { 450 syslog(LOG_NOTICE, "strdup(): %m"); 451 bail(SLEEP_EXIT, 1); 452 } 453 if (*shell == '\0') /* Not overridden */ 454 shell = pwd->pw_shell; 455 if ((shell = strdup(shell)) == NULL) { 456 syslog(LOG_NOTICE, "strdup(): %m"); 457 bail(SLEEP_EXIT, 1); 458 } 459 460 /* 461 * Set device protections, depending on what terminal the 462 * user is logged in. This feature is used on Suns to give 463 * console users better privacy. 464 */ 465 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 466 467 /* 468 * Clear flags of the tty. None should be set, and when the 469 * user sets them otherwise, this can cause the chown to fail. 470 * Since it isn't clear that flags are useful on character 471 * devices, we just clear them. 472 * 473 * We don't log in the case of EOPNOTSUPP because dev might be 474 * on NFS, which doesn't support chflags. 475 * 476 * We don't log in the EROFS because that means that /dev is on 477 * a read only file system and we assume that the permissions there 478 * are sane. 479 */ 480 if (ttyn != tname && chflags(ttyn, 0)) 481 if (errno != EOPNOTSUPP && errno != EROFS) 482 syslog(LOG_ERR, "chflags(%s): %m", ttyn); 483 if (ttyn != tname && chown(ttyn, pwd->pw_uid, 484 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 485 if (errno != EROFS) 486 syslog(LOG_ERR, "chown(%s): %m", ttyn); 487 488 #ifdef LOGALL 489 /* 490 * Syslog each successful login, so we don't have to watch 491 * hundreds of wtmp or lastlogin files. 492 */ 493 if (hflag) 494 syslog(LOG_INFO, "login from %s on %s as %s", 495 hostname, tty, pwd->pw_name); 496 else 497 syslog(LOG_INFO, "login on %s as %s", 498 tty, pwd->pw_name); 499 #endif 500 501 /* 502 * If fflag is on, assume caller/authenticator has logged root 503 * login. 504 */ 505 if (rootlogin && fflag == 0) { 506 if (hflag) 507 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 508 username, tty, hostname); 509 else 510 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 511 username, tty); 512 } 513 514 /* 515 * Destroy environment unless user has requested its 516 * preservation - but preserve TERM in all cases 517 */ 518 term = getenv("TERM"); 519 if (!pflag) 520 environ = envinit; 521 if (term != NULL) 522 setenv("TERM", term, 0); 523 524 /* 525 * PAM modules might add supplementary groups during pam_setcred(). 526 */ 527 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 528 syslog(LOG_ERR, "setusercontext() failed - exiting"); 529 bail(NO_SLEEP_EXIT, 1); 530 } 531 532 pam_err = pam_setcred(pamh, pam_silent|PAM_REINITIALIZE_CRED); 533 if (pam_err != PAM_SUCCESS) { 534 pam_syslog("pam_setcred()"); 535 bail(NO_SLEEP_EXIT, 1); 536 } 537 538 pam_err = pam_open_session(pamh, pam_silent); 539 if (pam_err != PAM_SUCCESS) { 540 pam_syslog("pam_open_session()"); 541 bail(NO_SLEEP_EXIT, 1); 542 } 543 pam_session_established = 1; 544 545 /* 546 * We must fork() before setuid() because we need to call 547 * pam_close_session() as root. 548 */ 549 pid = fork(); 550 if (pid < 0) { 551 err(1, "fork"); 552 } else if (pid != 0) { 553 /* 554 * Parent: wait for child to finish, then clean up 555 * session. 556 * 557 * If we get SIGHUP or SIGTERM, clean up the session 558 * and exit right away. This will make the terminal 559 * inaccessible and send SIGHUP to the foreground 560 * process group. 561 */ 562 int status; 563 setproctitle("-%s [pam]", getprogname()); 564 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 565 waitpid(pid, &status, 0); 566 (void)sigprocmask(SIG_BLOCK, &mask, NULL); 567 bail(NO_SLEEP_EXIT, 0); 568 } 569 570 /* 571 * NOTICE: We are now in the child process! 572 */ 573 574 /* 575 * Add any environment variables the PAM modules may have set. 576 */ 577 export_pam_environment(); 578 579 /* 580 * We're done with PAM now; our parent will deal with the rest. 581 */ 582 pam_end(pamh, 0); 583 pamh = NULL; 584 585 /* 586 * We don't need to be root anymore, so set the login name and 587 * the UID. 588 */ 589 if (setlogin(username) != 0) { 590 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 591 bail(NO_SLEEP_EXIT, 1); 592 } 593 if (setusercontext(lc, pwd, pwd->pw_uid, 594 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 595 syslog(LOG_ERR, "setusercontext() failed - exiting"); 596 exit(1); 597 } 598 599 (void)setenv("SHELL", pwd->pw_shell, 1); 600 (void)setenv("HOME", pwd->pw_dir, 1); 601 /* Overwrite "term" from login.conf(5) for any known TERM */ 602 if (term == NULL && (tp = stypeof(tty)) != NULL) 603 (void)setenv("TERM", tp, 1); 604 else 605 (void)setenv("TERM", TERM_UNKNOWN, 0); 606 (void)setenv("LOGNAME", username, 1); 607 (void)setenv("USER", username, 1); 608 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0); 609 610 if (!quietlog) { 611 const char *cw; 612 613 cw = login_getcapstr(lc, "welcome", NULL, NULL); 614 if (cw != NULL && access(cw, F_OK) == 0) 615 motd(cw); 616 else 617 motd(_PATH_MOTDFILE); 618 619 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 && 620 login_getcapbool(lc, "nocheckmail", 0) == 0) { 621 char *cx; 622 623 /* $MAIL may have been set by class. */ 624 cx = getenv("MAIL"); 625 if (cx == NULL) { 626 asprintf(&cx, "%s/%s", 627 _PATH_MAILDIR, pwd->pw_name); 628 } 629 if (cx && stat(cx, &st) == 0 && st.st_size != 0) 630 (void)printf("You have %smail.\n", 631 (st.st_mtime > st.st_atime) ? "new " : ""); 632 if (getenv("MAIL") == NULL) 633 free(cx); 634 } 635 } 636 637 login_close(lc_user); 638 login_close(lc); 639 640 sa.sa_handler = SIG_DFL; 641 (void)sigaction(SIGALRM, &sa, NULL); 642 (void)sigaction(SIGQUIT, &sa, NULL); 643 (void)sigaction(SIGINT, &sa, NULL); 644 (void)sigaction(SIGTERM, &sa, NULL); 645 (void)sigaction(SIGHUP, &sa, NULL); 646 sa.sa_handler = SIG_IGN; 647 (void)sigaction(SIGTSTP, &sa, NULL); 648 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 649 650 /* 651 * Login shells have a leading '-' in front of argv[0] 652 */ 653 p = strrchr(pwd->pw_shell, '/'); 654 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) { 655 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 656 username); 657 errx(1, "shell exceeds maximum pathname size"); 658 } else if (arg0 == NULL) { 659 err(1, "asprintf()"); 660 } 661 662 execlp(shell, arg0, (char *)0); 663 err(1, "%s", shell); 664 665 /* 666 * That's it, folks! 667 */ 668 } 669 670 /* 671 * Attempt to authenticate the user using PAM. Returns 0 if the user is 672 * authenticated, or 1 if not authenticated. If some sort of PAM system 673 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 674 * function returns -1. This can be used as an indication that we should 675 * fall back to a different authentication mechanism. 676 */ 677 static int 678 auth_pam(void) 679 { 680 const char *tmpl_user; 681 const void *item; 682 int rval; 683 684 pam_err = pam_authenticate(pamh, pam_silent); 685 switch (pam_err) { 686 687 case PAM_SUCCESS: 688 /* 689 * With PAM we support the concept of a "template" 690 * user. The user enters a login name which is 691 * authenticated by PAM, usually via a remote service 692 * such as RADIUS or TACACS+. If authentication 693 * succeeds, a different but related "template" name 694 * is used for setting the credentials, shell, and 695 * home directory. The name the user enters need only 696 * exist on the remote authentication server, but the 697 * template name must be present in the local password 698 * database. 699 * 700 * This is supported by two various mechanisms in the 701 * individual modules. However, from the application's 702 * point of view, the template user is always passed 703 * back as a changed value of the PAM_USER item. 704 */ 705 pam_err = pam_get_item(pamh, PAM_USER, &item); 706 if (pam_err == PAM_SUCCESS) { 707 tmpl_user = (const char *)item; 708 if (strcmp(username, tmpl_user) != 0) 709 pwd = getpwnam(tmpl_user); 710 } else { 711 pam_syslog("pam_get_item(PAM_USER)"); 712 } 713 rval = 0; 714 break; 715 716 case PAM_AUTH_ERR: 717 case PAM_USER_UNKNOWN: 718 case PAM_MAXTRIES: 719 rval = 1; 720 break; 721 722 default: 723 pam_syslog("pam_authenticate()"); 724 rval = -1; 725 break; 726 } 727 728 if (rval == 0) { 729 pam_err = pam_acct_mgmt(pamh, pam_silent); 730 switch (pam_err) { 731 case PAM_SUCCESS: 732 break; 733 case PAM_NEW_AUTHTOK_REQD: 734 pam_err = pam_chauthtok(pamh, 735 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK); 736 if (pam_err != PAM_SUCCESS) { 737 pam_syslog("pam_chauthtok()"); 738 rval = 1; 739 } 740 break; 741 default: 742 pam_syslog("pam_acct_mgmt()"); 743 rval = 1; 744 break; 745 } 746 } 747 748 if (rval != 0) { 749 pam_end(pamh, pam_err); 750 pamh = NULL; 751 } 752 return (rval); 753 } 754 755 /* 756 * Export any environment variables PAM modules may have set 757 */ 758 static void 759 export_pam_environment(void) 760 { 761 char **pam_env; 762 char **pp; 763 764 pam_env = pam_getenvlist(pamh); 765 if (pam_env != NULL) { 766 for (pp = pam_env; *pp != NULL; pp++) { 767 (void)export(*pp); 768 free(*pp); 769 } 770 } 771 } 772 773 /* 774 * Perform sanity checks on an environment variable: 775 * - Make sure there is an '=' in the string. 776 * - Make sure the string doesn't run on too long. 777 * - Do not export certain variables. This list was taken from the 778 * Solaris pam_putenv(3) man page. 779 * Then export it. 780 */ 781 static int 782 export(const char *s) 783 { 784 static const char *noexport[] = { 785 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 786 "IFS", "PATH", NULL 787 }; 788 char *p; 789 const char **pp; 790 size_t n; 791 int rv; 792 793 if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL) 794 return (0); 795 if (strncmp(s, "LD_", 3) == 0) 796 return (0); 797 for (pp = noexport; *pp != NULL; pp++) { 798 n = strlen(*pp); 799 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 800 return (0); 801 } 802 *p = '\0'; 803 rv = setenv(s, p + 1, 1); 804 *p = '='; 805 if (rv == -1) 806 return (0); 807 return (1); 808 } 809 810 static void 811 usage(void) 812 { 813 814 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 815 exit(1); 816 } 817 818 /* 819 * Prompt user and read login name from stdin. 820 */ 821 static char * 822 getloginname(void) 823 { 824 char *nbuf, *p; 825 int ch; 826 827 nbuf = malloc(MAXLOGNAME); 828 if (nbuf == NULL) 829 err(1, "malloc()"); 830 do { 831 (void)printf("%s", prompt); 832 for (p = nbuf; (ch = getchar()) != '\n'; ) { 833 if (ch == EOF) { 834 badlogin(username); 835 bail(NO_SLEEP_EXIT, 0); 836 } 837 if (p < nbuf + MAXLOGNAME - 1) 838 *p++ = ch; 839 } 840 } while (p == nbuf); 841 842 *p = '\0'; 843 if (nbuf[0] == '-') { 844 pam_silent = 0; 845 memmove(nbuf, nbuf + 1, strlen(nbuf)); 846 } else { 847 pam_silent = PAM_SILENT; 848 } 849 return nbuf; 850 } 851 852 /* 853 * SIGINT handler for motd(). 854 */ 855 static volatile int motdinterrupt; 856 static void 857 sigint(int signo __unused) 858 { 859 motdinterrupt = 1; 860 } 861 862 /* 863 * Display the contents of a file (such as /etc/motd). 864 */ 865 static int 866 motd(const char *motdfile) 867 { 868 struct sigaction newint, oldint; 869 FILE *f; 870 int ch; 871 872 if ((f = fopen(motdfile, "r")) == NULL) 873 return (-1); 874 motdinterrupt = 0; 875 newint.sa_handler = sigint; 876 newint.sa_flags = 0; 877 sigfillset(&newint.sa_mask); 878 sigaction(SIGINT, &newint, &oldint); 879 while ((ch = fgetc(f)) != EOF && !motdinterrupt) 880 putchar(ch); 881 sigaction(SIGINT, &oldint, NULL); 882 if (ch != EOF || ferror(f)) { 883 fclose(f); 884 return (-1); 885 } 886 fclose(f); 887 return (0); 888 } 889 890 /* 891 * SIGALRM handler, to enforce login prompt timeout. 892 * 893 * XXX This can potentially confuse the hell out of PAM. We should 894 * XXX instead implement a conversation function that returns 895 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal 896 * XXX handler just set a flag. 897 */ 898 static void 899 timedout(int signo __unused) 900 { 901 902 longjmp(timeout_buf, signo); 903 } 904 905 static void 906 badlogin(char *name) 907 { 908 909 if (failures == 0) 910 return; 911 if (hflag) { 912 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 913 failures, failures > 1 ? "S" : "", hostname); 914 syslog(LOG_AUTHPRIV|LOG_NOTICE, 915 "%d LOGIN FAILURE%s FROM %s, %s", 916 failures, failures > 1 ? "S" : "", hostname, name); 917 } else { 918 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 919 failures, failures > 1 ? "S" : "", tty); 920 syslog(LOG_AUTHPRIV|LOG_NOTICE, 921 "%d LOGIN FAILURE%s ON %s, %s", 922 failures, failures > 1 ? "S" : "", tty, name); 923 } 924 failures = 0; 925 } 926 927 const char * 928 stypeof(char *ttyid) 929 { 930 struct ttyent *t; 931 932 if (ttyid != NULL && *ttyid != '\0') { 933 t = getttynam(ttyid); 934 if (t != NULL && t->ty_type != NULL) 935 return (t->ty_type); 936 } 937 return (NULL); 938 } 939 940 static void 941 refused(const char *msg, const char *rtype, int lout) 942 { 943 944 if (msg != NULL) 945 printf("%s.\n", msg); 946 if (hflag) 947 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 948 pwd->pw_name, rtype, hostname, tty); 949 else 950 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 951 pwd->pw_name, rtype, tty); 952 if (lout) 953 bail(SLEEP_EXIT, 1); 954 } 955 956 /* 957 * Log a PAM error 958 */ 959 static void 960 pam_syslog(const char *msg) 961 { 962 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err)); 963 } 964 965 /* 966 * Shut down PAM 967 */ 968 static void 969 pam_cleanup(void) 970 { 971 972 if (pamh != NULL) { 973 if (pam_session_established) { 974 pam_err = pam_close_session(pamh, 0); 975 if (pam_err != PAM_SUCCESS) 976 pam_syslog("pam_close_session()"); 977 } 978 pam_session_established = 0; 979 if (pam_cred_established) { 980 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED); 981 if (pam_err != PAM_SUCCESS) 982 pam_syslog("pam_setcred()"); 983 } 984 pam_cred_established = 0; 985 pam_end(pamh, pam_err); 986 pamh = NULL; 987 } 988 } 989 990 static void 991 bail_internal(int sec, int eval, int signo) 992 { 993 struct sigaction sa; 994 995 pam_cleanup(); 996 #ifdef USE_BSM_AUDIT 997 if (pwd != NULL) 998 audit_logout(); 999 #endif 1000 (void)sleep(sec); 1001 if (signo == 0) 1002 exit(eval); 1003 else { 1004 sa.sa_handler = SIG_DFL; 1005 sa.sa_flags = 0; 1006 (void)sigemptyset(&sa.sa_mask); 1007 (void)sigaction(signo, &sa, NULL); 1008 (void)sigaddset(&sa.sa_mask, signo); 1009 (void)sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL); 1010 raise(signo); 1011 exit(128 + signo); 1012 } 1013 } 1014 1015 /* 1016 * Exit, optionally after sleeping a few seconds 1017 */ 1018 static void 1019 bail(int sec, int eval) 1020 { 1021 bail_internal(sec, eval, 0); 1022 } 1023 1024 /* 1025 * Exit because of a signal. 1026 * This is not async-signal safe, so only call async-signal safe functions 1027 * while the signal is unmasked. 1028 */ 1029 static void 1030 bail_sig(int signo) 1031 { 1032 bail_internal(NO_SLEEP_EXIT, 0, signo); 1033 } 1034