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 * @(#)login.c 8.4 (Berkeley) 4/2/94 41 * $FreeBSD: src/usr.bin/login/login.c,v 1.106 2007/07/04 00:00:40 scf Exp $ 42 * $DragonFly: src/usr.bin/login/login.c,v 1.6 2006/01/12 13:43:11 corecode Exp $ 43 */ 44 45 /* 46 * login [ name ] 47 * login -h hostname (for telnetd, etc.) 48 * login -f name (for pre-authenticated login: datakit, xterm, etc.) 49 */ 50 51 #include <sys/copyright.h> 52 #include <sys/param.h> 53 #include <sys/file.h> 54 #include <sys/stat.h> 55 #include <sys/time.h> 56 #include <sys/resource.h> 57 #include <sys/wait.h> 58 59 #include <err.h> 60 #include <errno.h> 61 #include <grp.h> 62 #include <libutil.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 int export(const char *); 83 static void export_pam_environment(void); 84 static int motd(const char *); 85 static void badlogin(char *); 86 static char *getloginname(void); 87 static void pam_syslog(const char *); 88 static void pam_cleanup(void); 89 static void refused(const char *, const char *, int); 90 static const char *stypeof(char *); 91 static void sigint(int); 92 static void timedout(int); 93 static void usage(void); 94 95 #define TTYGRPNAME "tty" /* group to own ttys */ 96 #define DEFAULT_BACKOFF 3 97 #define DEFAULT_RETRIES 10 98 #define DEFAULT_PROMPT "login: " 99 #define DEFAULT_PASSWD_PROMPT "Password:" 100 #define TERM_UNKNOWN "su" 101 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 102 #define NO_SLEEP_EXIT 0 103 #define SLEEP_EXIT 5 104 105 /* 106 * This bounds the time given to login. Not a define so it can 107 * be patched on machines where it's too small. 108 */ 109 static u_int timeout = 300; 110 111 /* Buffer for signal handling of timeout */ 112 static jmp_buf timeout_buf; 113 114 struct passwd *pwd; 115 static int failures; 116 117 static char *envinit[1]; /* empty environment list */ 118 119 /* 120 * Command line flags and arguments 121 */ 122 static int fflag; /* -f: do not perform authentication */ 123 static int hflag; /* -h: login from remote host */ 124 static char *hostname; /* hostname from command line */ 125 static int pflag; /* -p: preserve environment */ 126 127 /* 128 * User name 129 */ 130 static char *username; /* user name */ 131 static char *olduser; /* previous user name */ 132 133 /* 134 * Prompts 135 */ 136 static char default_prompt[] = DEFAULT_PROMPT; 137 static const char *prompt; 138 static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT; 139 static const char *passwd_prompt; 140 141 static char *tty; 142 143 /* 144 * PAM data 145 */ 146 static pam_handle_t *pamh = NULL; 147 static struct pam_conv pamc = { openpam_ttyconv, NULL }; 148 static int pam_err; 149 static int pam_silent = PAM_SILENT; 150 static int pam_cred_established; 151 static int pam_session_established; 152 153 int 154 main(int argc, char **argv) 155 { 156 struct group *gr; 157 struct stat st; 158 int retries, backoff; 159 int ask, ch, cnt, quietlog, rootlogin, rval; 160 uid_t uid, euid; 161 gid_t egid; 162 char *term; 163 char *p, *ttyn; 164 char tname[sizeof(_PATH_TTY) + 10]; 165 char *arg0; 166 const char *tp; 167 const char *shell = NULL; 168 login_cap_t *lc = NULL; 169 login_cap_t *lc_user = NULL; 170 pid_t pid; 171 #ifdef USE_BSM_AUDIT 172 char auditsuccess = 1; 173 #endif 174 175 signal(SIGQUIT, SIG_IGN); 176 signal(SIGINT, SIG_IGN); 177 signal(SIGHUP, SIG_IGN); 178 if (setjmp(timeout_buf)) { 179 if (failures) 180 badlogin(username); 181 fprintf(stderr, "Login timed out after %d seconds\n", 182 timeout); 183 bail(NO_SLEEP_EXIT, 0); 184 } 185 signal(SIGALRM, timedout); 186 alarm(timeout); 187 setpriority(PRIO_PROCESS, 0, 0); 188 189 openlog("login", LOG_ODELAY, LOG_AUTH); 190 191 uid = getuid(); 192 euid = geteuid(); 193 egid = getegid(); 194 195 while ((ch = getopt(argc, argv, "fh:p")) != -1) 196 switch (ch) { 197 case 'f': 198 fflag = 1; 199 break; 200 case 'h': 201 if (uid != 0) 202 errx(1, "-h option: %s", strerror(EPERM)); 203 if (strlen(optarg) >= MAXHOSTNAMELEN) 204 errx(1, "-h option: %s: exceeds maximum " 205 "hostname size", optarg); 206 hflag = 1; 207 hostname = optarg; 208 break; 209 case 'p': 210 pflag = 1; 211 break; 212 case '?': 213 default: 214 if (uid == 0) 215 syslog(LOG_ERR, "invalid flag %c", ch); 216 usage(); 217 } 218 argc -= optind; 219 argv += optind; 220 221 if (argc > 0) { 222 username = strdup(*argv); 223 if (username == NULL) 224 err(1, "strdup()"); 225 ask = 0; 226 } else { 227 ask = 1; 228 } 229 230 setproctitle("-%s", getprogname()); 231 232 for (cnt = getdtablesize(); cnt > 2; cnt--) 233 close(cnt); 234 235 /* 236 * Get current TTY 237 */ 238 ttyn = ttyname(STDIN_FILENO); 239 if (ttyn == NULL || *ttyn == '\0') { 240 snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 241 ttyn = tname; 242 } 243 if (strncmp(ttyn, _PATH_DEV, sizeof(_PATH_DEV) -1) == 0) 244 tty = ttyn + sizeof(_PATH_DEV) -1; 245 else 246 tty = ttyn; 247 248 /* 249 * Get "login-retries" & "login-backoff" from default class 250 */ 251 lc = login_getclass(NULL); 252 prompt = login_getcapstr(lc, "login_prompt", 253 default_prompt, default_prompt); 254 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 255 default_passwd_prompt, default_passwd_prompt); 256 retries = login_getcapnum(lc, "login-retries", 257 DEFAULT_RETRIES, DEFAULT_RETRIES); 258 backoff = login_getcapnum(lc, "login-backoff", 259 DEFAULT_BACKOFF, DEFAULT_BACKOFF); 260 login_close(lc); 261 lc = NULL; 262 263 /* 264 * Try to authenticate the user until we succeed or time out. 265 */ 266 for (cnt = 0;; ask = 1) { 267 if (ask) { 268 fflag = 0; 269 if (olduser != NULL) 270 free(olduser); 271 olduser = username; 272 username = getloginname(); 273 } 274 rootlogin = 0; 275 276 /* 277 * Note if trying multiple user names; log failures for 278 * previous user name, but don't bother logging one failure 279 * for nonexistent name (mistyped username). 280 */ 281 if (failures && strcmp(olduser, username) != 0) { 282 if (failures > (pwd ? 0 : 1)) 283 badlogin(olduser); 284 } 285 286 /* 287 * Load the PAM policy and set some variables 288 */ 289 pam_err = pam_start("login", username, &pamc, &pamh); 290 if (pam_err != PAM_SUCCESS) { 291 pam_syslog("pam_start()"); 292 #ifdef USE_BSM_AUDIT 293 au_login_fail("PAM Error", 1); 294 #endif 295 bail(NO_SLEEP_EXIT, 1); 296 } 297 pam_err = pam_set_item(pamh, PAM_TTY, tty); 298 if (pam_err != PAM_SUCCESS) { 299 pam_syslog("pam_set_item(PAM_TTY)"); 300 #ifdef USE_BSM_AUDIT 301 au_login_fail("PAM Error", 1); 302 #endif 303 bail(NO_SLEEP_EXIT, 1); 304 } 305 pam_err = pam_set_item(pamh, PAM_RHOST, hostname); 306 if (pam_err != PAM_SUCCESS) { 307 pam_syslog("pam_set_item(PAM_RHOST)"); 308 #ifdef USE_BSM_AUDIT 309 au_login_fail("PAM Error", 1); 310 #endif 311 bail(NO_SLEEP_EXIT, 1); 312 } 313 314 pwd = getpwnam(username); 315 if (pwd != NULL && pwd->pw_uid == 0) 316 rootlogin = 1; 317 318 /* 319 * If the -f option was specified and the caller is 320 * root or the caller isn't changing their uid, don't 321 * authenticate. 322 */ 323 if (pwd != NULL && fflag && 324 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) { 325 /* already authenticated */ 326 rval = 0; 327 #ifdef USE_BSM_AUDIT 328 auditsuccess = 0; /* opened a terminal window only */ 329 #endif 330 } else { 331 fflag = 0; 332 setpriority(PRIO_PROCESS, 0, -4); 333 rval = auth_pam(); 334 setpriority(PRIO_PROCESS, 0, 0); 335 } 336 337 if (pwd && rval == 0) 338 break; 339 340 pam_cleanup(); 341 342 /* 343 * We are not exiting here, but this corresponds to a failed 344 * login event, so set exitstatus to 1. 345 */ 346 #ifdef USE_BSM_AUDIT 347 au_login_fail("Login incorrect", 1); 348 #endif 349 350 printf("Login incorrect\n"); 351 failures++; 352 353 pwd = NULL; 354 355 /* 356 * Allow up to 'retry' (10) attempts, but start 357 * backing off after 'backoff' (3) attempts. 358 */ 359 if (++cnt > backoff) { 360 if (cnt >= retries) { 361 badlogin(username); 362 bail(SLEEP_EXIT, 1); 363 } 364 sleep((u_int)((cnt - backoff) * 5)); 365 } 366 } 367 368 /* committed to login -- turn off timeout */ 369 alarm((u_int)0); 370 signal(SIGHUP, SIG_DFL); 371 372 endpwent(); 373 374 #ifdef USE_BSM_AUDIT 375 /* Audit successful login. */ 376 if (auditsuccess) 377 au_login_success(); 378 #endif 379 380 /* 381 * Establish the login class. 382 */ 383 lc = login_getpwclass(pwd); 384 lc_user = login_getuserclass(pwd); 385 386 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0))) 387 quietlog = login_getcapbool(lc, "hushlogin", 0); 388 389 /* 390 * Switching needed for NFS with root access disabled. 391 * 392 * XXX: This change fails to modify the additional groups for the 393 * process, and as such, may restrict rights normally granted 394 * through those groups. 395 */ 396 setegid(pwd->pw_gid); 397 seteuid(rootlogin ? 0 : pwd->pw_uid); 398 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 399 if (login_getcapbool(lc, "requirehome", 0)) 400 refused("Home directory not available", "HOMEDIR", 1); 401 if (chdir("/") < 0) 402 refused("Cannot find root directory", "ROOTDIR", 1); 403 if (!quietlog || *pwd->pw_dir) 404 printf("No home directory.\nLogging in with home = \"/\".\n"); 405 pwd->pw_dir = strdup("/"); 406 if (pwd->pw_dir == NULL) { 407 syslog(LOG_NOTICE, "strdup(): %m"); 408 bail(SLEEP_EXIT, 1); 409 } 410 } 411 seteuid(euid); 412 setegid(egid); 413 if (!quietlog) { 414 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 415 if (!quietlog) 416 pam_silent = 0; 417 } 418 419 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 420 if (*pwd->pw_shell == '\0') 421 pwd->pw_shell = strdup(_PATH_BSHELL); 422 if (pwd->pw_shell == NULL) { 423 syslog(LOG_NOTICE, "strdup(): %m"); 424 bail(SLEEP_EXIT, 1); 425 } 426 if (*shell == '\0') /* Not overridden */ 427 shell = pwd->pw_shell; 428 if ((shell = strdup(shell)) == NULL) { 429 syslog(LOG_NOTICE, "strdup(): %m"); 430 bail(SLEEP_EXIT, 1); 431 } 432 433 /* 434 * Set device protections, depending on what terminal the 435 * user is logged in. This feature is used on Suns to give 436 * console users better privacy. 437 */ 438 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 439 440 /* 441 * Clear flags of the tty. None should be set, and when the 442 * user sets them otherwise, this can cause the chown to fail. 443 * Since it isn't clear that flags are useful on character 444 * devices, we just clear them. 445 * 446 * We don't log in the case of EOPNOTSUPP because dev might be 447 * on NFS, which doesn't support chflags. 448 * 449 * We don't log in the EROFS because that means that /dev is on 450 * a read only file system and we assume that the permissions there 451 * are sane. 452 */ 453 if (ttyn != tname && chflags(ttyn, 0)) 454 if (errno != EOPNOTSUPP && errno != EROFS) 455 syslog(LOG_ERR, "chflags(%s): %m", ttyn); 456 if (ttyn != tname && chown(ttyn, pwd->pw_uid, 457 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 458 if (errno != EROFS) 459 syslog(LOG_ERR, "chown(%s): %m", ttyn); 460 461 /* 462 * Exclude cons/vt/ptys only, assume dialup otherwise 463 * TODO: Make dialup tty determination a library call 464 * for consistency (finger etc.) 465 */ 466 if (hflag && isdialuptty(tty)) 467 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 468 469 #ifdef LOGALL 470 /* 471 * Syslog each successful login, so we don't have to watch 472 * hundreds of wtmp or lastlogin files. 473 */ 474 if (hflag) 475 syslog(LOG_INFO, "login from %s on %s as %s", 476 hostname, tty, pwd->pw_name); 477 else 478 syslog(LOG_INFO, "login on %s as %s", 479 tty, pwd->pw_name); 480 #endif 481 482 /* 483 * If fflag is on, assume caller/authenticator has logged root 484 * login. 485 */ 486 if (rootlogin && fflag == 0) { 487 if (hflag) 488 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 489 username, tty, hostname); 490 else 491 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 492 username, tty); 493 } 494 495 /* 496 * Destroy environment unless user has requested its 497 * preservation - but preserve TERM in all cases 498 */ 499 term = getenv("TERM"); 500 if (!pflag) 501 environ = envinit; 502 if (term != NULL) { 503 if (setenv("TERM", term, 0) == -1) 504 err(1, "setenv: cannot set TERM=%s", term); 505 } 506 507 /* 508 * PAM modules might add supplementary groups during pam_setcred(). 509 */ 510 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 511 syslog(LOG_ERR, "setusercontext() failed - exiting"); 512 bail(NO_SLEEP_EXIT, 1); 513 } 514 515 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED); 516 if (pam_err != PAM_SUCCESS) { 517 pam_syslog("pam_setcred()"); 518 bail(NO_SLEEP_EXIT, 1); 519 } 520 pam_cred_established = 1; 521 522 pam_err = pam_open_session(pamh, pam_silent); 523 if (pam_err != PAM_SUCCESS) { 524 pam_syslog("pam_open_session()"); 525 bail(NO_SLEEP_EXIT, 1); 526 } 527 pam_session_established = 1; 528 529 /* 530 * We must fork() before setuid() because we need to call 531 * pam_close_session() as root. 532 */ 533 pid = fork(); 534 if (pid < 0) { 535 err(1, "fork"); 536 } else if (pid != 0) { 537 /* 538 * Parent: wait for child to finish, then clean up 539 * session. 540 */ 541 int status; 542 setproctitle("-%s [pam]", getprogname()); 543 waitpid(pid, &status, 0); 544 bail(NO_SLEEP_EXIT, 0); 545 } 546 547 /* 548 * NOTICE: We are now in the child process! 549 */ 550 551 /* 552 * Add any environment variables the PAM modules may have set. 553 */ 554 export_pam_environment(); 555 556 /* 557 * We're done with PAM now; our parent will deal with the rest. 558 */ 559 pam_end(pamh, 0); 560 pamh = NULL; 561 562 /* 563 * We don't need to be root anymore, so set the login name and 564 * the UID. 565 */ 566 if (setlogin(username) != 0) { 567 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 568 bail(NO_SLEEP_EXIT, 1); 569 } 570 if (setusercontext(lc, pwd, pwd->pw_uid, 571 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 572 syslog(LOG_ERR, "setusercontext() failed - exiting"); 573 exit(1); 574 } 575 576 if (setenv("SHELL", pwd->pw_shell, 1) == -1) 577 err(1, "setenv: cannot set SHELL=%s", pwd->pw_shell); 578 if (setenv("HOME", pwd->pw_dir, 1) == -1) 579 err(1, "setenv: cannot set HOME=%s", pwd->pw_dir); 580 /* Overwrite "term" from login.conf(5) for any known TERM */ 581 if (term == NULL && (tp = stypeof(tty)) != NULL) { 582 if (setenv("TERM", tp, 1) == -1) 583 err(1, "setenv: cannot set TERM=%s", tp); 584 } else { 585 if (setenv("TERM", TERM_UNKNOWN, 0) == -1) 586 err(1, "setenv: cannot set TERM=%s", TERM_UNKNOWN); 587 } 588 589 if (setenv("LOGNAME", username, 1) == -1) 590 err(1, "setenv: cannot set LOGNAME=%s", username); 591 if (setenv("USER", username, 1) == -1) 592 err(1, "setenv: cannot set USER=%s", username); 593 if (setenv("PATH", 594 rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0) == -1) { 595 err(1, "setenv: cannot set PATH=%s", 596 rootlogin ? _PATH_STDPATH : _PATH_DEFPATH); 597 } 598 599 if (!quietlog) { 600 const char *cw; 601 602 cw = login_getcapstr(lc, "copyright", NULL, NULL); 603 if (cw == NULL || motd(cw) == -1) 604 printf("%s", copyright); 605 606 printf("\n"); 607 608 cw = login_getcapstr(lc, "welcome", NULL, NULL); 609 if (cw != NULL && access(cw, F_OK) == 0) 610 motd(cw); 611 else 612 motd(_PATH_MOTDFILE); 613 614 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 && 615 login_getcapbool(lc, "nocheckmail", 0) == 0) { 616 char *cx; 617 618 /* $MAIL may have been set by class. */ 619 cx = getenv("MAIL"); 620 if (cx == NULL) { 621 asprintf(&cx, "%s/%s", 622 _PATH_MAILDIR, pwd->pw_name); 623 } 624 if (cx && stat(cx, &st) == 0 && st.st_size != 0) 625 printf("You have %smail.\n", 626 (st.st_mtime > st.st_atime) ? "new " : ""); 627 if (getenv("MAIL") == NULL) 628 free(cx); 629 } 630 } 631 632 login_close(lc_user); 633 login_close(lc); 634 635 signal(SIGALRM, SIG_DFL); 636 signal(SIGQUIT, SIG_DFL); 637 signal(SIGINT, SIG_DFL); 638 signal(SIGTSTP, SIG_IGN); 639 640 /* 641 * Login shells have a leading '-' in front of argv[0] 642 */ 643 p = strrchr(pwd->pw_shell, '/'); 644 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) { 645 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 646 username); 647 errx(1, "shell exceeds maximum pathname size"); 648 } else if (arg0 == NULL) { 649 err(1, "asprintf()"); 650 } 651 652 execlp(shell, arg0, NULL); 653 err(1, "%s", shell); 654 655 /* 656 * That's it, folks! 657 */ 658 } 659 660 /* 661 * Attempt to authenticate the user using PAM. Returns 0 if the user is 662 * authenticated, or 1 if not authenticated. If some sort of PAM system 663 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 664 * function returns -1. This can be used as an indication that we should 665 * fall back to a different authentication mechanism. 666 */ 667 static int 668 auth_pam(void) 669 { 670 const char *tmpl_user; 671 const void *item; 672 int rval; 673 674 pam_err = pam_authenticate(pamh, pam_silent); 675 switch (pam_err) { 676 677 case PAM_SUCCESS: 678 /* 679 * With PAM we support the concept of a "template" 680 * user. The user enters a login name which is 681 * authenticated by PAM, usually via a remote service 682 * such as RADIUS or TACACS+. If authentication 683 * succeeds, a different but related "template" name 684 * is used for setting the credentials, shell, and 685 * home directory. The name the user enters need only 686 * exist on the remote authentication server, but the 687 * template name must be present in the local password 688 * database. 689 * 690 * This is supported by two various mechanisms in the 691 * individual modules. However, from the application's 692 * point of view, the template user is always passed 693 * back as a changed value of the PAM_USER item. 694 */ 695 pam_err = pam_get_item(pamh, PAM_USER, &item); 696 if (pam_err == PAM_SUCCESS) { 697 tmpl_user = (const char *)item; 698 if (strcmp(username, tmpl_user) != 0) 699 pwd = getpwnam(tmpl_user); 700 } else { 701 pam_syslog("pam_get_item(PAM_USER)"); 702 } 703 rval = 0; 704 break; 705 706 case PAM_AUTH_ERR: 707 case PAM_USER_UNKNOWN: 708 case PAM_MAXTRIES: 709 rval = 1; 710 break; 711 712 default: 713 pam_syslog("pam_authenticate()"); 714 rval = -1; 715 break; 716 } 717 718 if (rval == 0) { 719 pam_err = pam_acct_mgmt(pamh, pam_silent); 720 switch (pam_err) { 721 case PAM_SUCCESS: 722 break; 723 case PAM_NEW_AUTHTOK_REQD: 724 pam_err = pam_chauthtok(pamh, 725 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK); 726 if (pam_err != PAM_SUCCESS) { 727 pam_syslog("pam_chauthtok()"); 728 rval = 1; 729 } 730 break; 731 default: 732 pam_syslog("pam_acct_mgmt()"); 733 rval = 1; 734 break; 735 } 736 } 737 738 if (rval != 0) { 739 pam_end(pamh, pam_err); 740 pamh = NULL; 741 } 742 return (rval); 743 } 744 745 /* 746 * Export any environment variables PAM modules may have set 747 */ 748 static void 749 export_pam_environment(void) 750 { 751 char **pam_env; 752 char **pp; 753 754 pam_env = pam_getenvlist(pamh); 755 if (pam_env != NULL) { 756 for (pp = pam_env; *pp != NULL; pp++) { 757 export(*pp); 758 free(*pp); 759 } 760 } 761 } 762 763 /* 764 * Perform sanity checks on an environment variable: 765 * - Make sure there is an '=' in the string. 766 * - Make sure the string doesn't run on too long. 767 * - Do not export certain variables. This list was taken from the 768 * Solaris pam_putenv(3) man page. 769 * Then export it. 770 */ 771 static int 772 export(const char *s) 773 { 774 static const char *noexport[] = { 775 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 776 "IFS", "PATH", NULL 777 }; 778 char *p; 779 const char **pp; 780 size_t n; 781 782 if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL) 783 return (0); 784 if (strncmp(s, "LD_", 3) == 0) 785 return (0); 786 for (pp = noexport; *pp != NULL; pp++) { 787 n = strlen(*pp); 788 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 789 return (0); 790 } 791 *p = '\0'; 792 if (setenv(s, p + 1, 1) == -1) 793 err(1, "setenv: cannot set %s=%s", s, p + 1); 794 *p = '='; 795 return (1); 796 } 797 798 static void 799 usage(void) 800 { 801 802 fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 803 exit(1); 804 } 805 806 /* 807 * Prompt user and read login name from stdin. 808 */ 809 static char * 810 getloginname(void) 811 { 812 char *nbuf, *p; 813 int ch; 814 815 nbuf = malloc(MAXLOGNAME); 816 if (nbuf == NULL) 817 err(1, "malloc()"); 818 do { 819 printf("%s", prompt); 820 for (p = nbuf; (ch = getchar()) != '\n'; ) { 821 if (ch == EOF) { 822 badlogin(username); 823 bail(NO_SLEEP_EXIT, 0); 824 } 825 if (p < nbuf + MAXLOGNAME - 1) 826 *p++ = ch; 827 } 828 } while (p == nbuf); 829 830 *p = '\0'; 831 if (nbuf[0] == '-') { 832 pam_silent = 0; 833 memmove(nbuf, nbuf + 1, strlen(nbuf)); 834 } else { 835 pam_silent = PAM_SILENT; 836 } 837 return nbuf; 838 } 839 840 /* 841 * SIGINT handler for motd(). 842 */ 843 static volatile int motdinterrupt; 844 static void 845 sigint(int signo __unused) 846 { 847 motdinterrupt = 1; 848 } 849 850 /* 851 * Display the contents of a file (such as /etc/motd). 852 */ 853 static int 854 motd(const char *motdfile) 855 { 856 sig_t oldint; 857 FILE *f; 858 int ch; 859 860 if ((f = fopen(motdfile, "r")) == NULL) 861 return (-1); 862 motdinterrupt = 0; 863 oldint = signal(SIGINT, sigint); 864 while ((ch = fgetc(f)) != EOF && !motdinterrupt) 865 putchar(ch); 866 signal(SIGINT, oldint); 867 if (ch != EOF || ferror(f)) { 868 fclose(f); 869 return (-1); 870 } 871 fclose(f); 872 return (0); 873 } 874 875 /* 876 * SIGALRM handler, to enforce login prompt timeout. 877 * 878 * XXX This can potentially confuse the hell out of PAM. We should 879 * XXX instead implement a conversation function that returns 880 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal 881 * XXX handler just set a flag. 882 */ 883 static void 884 timedout(int signo __unused) 885 { 886 887 longjmp(timeout_buf, signo); 888 } 889 890 static void 891 badlogin(char *name) 892 { 893 894 if (failures == 0) 895 return; 896 if (hflag) { 897 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 898 failures, failures > 1 ? "S" : "", hostname); 899 syslog(LOG_AUTHPRIV|LOG_NOTICE, 900 "%d LOGIN FAILURE%s FROM %s, %s", 901 failures, failures > 1 ? "S" : "", hostname, name); 902 } else { 903 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 904 failures, failures > 1 ? "S" : "", tty); 905 syslog(LOG_AUTHPRIV|LOG_NOTICE, 906 "%d LOGIN FAILURE%s ON %s, %s", 907 failures, failures > 1 ? "S" : "", tty, name); 908 } 909 failures = 0; 910 } 911 912 const char * 913 stypeof(char *ttyid) 914 { 915 struct ttyent *t; 916 917 if (ttyid != NULL && *ttyid != '\0') { 918 t = getttynam(ttyid); 919 if (t != NULL && t->ty_type != NULL) 920 return (t->ty_type); 921 } 922 return (NULL); 923 } 924 925 static void 926 refused(const char *msg, const char *rtype, int lout) 927 { 928 929 if (msg != NULL) 930 printf("%s.\n", msg); 931 if (hflag) 932 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 933 pwd->pw_name, rtype, hostname, tty); 934 else 935 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 936 pwd->pw_name, rtype, tty); 937 if (lout) 938 bail(SLEEP_EXIT, 1); 939 } 940 941 /* 942 * Log a PAM error 943 */ 944 static void 945 pam_syslog(const char *msg) 946 { 947 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err)); 948 } 949 950 /* 951 * Shut down PAM 952 */ 953 static void 954 pam_cleanup(void) 955 { 956 957 if (pamh != NULL) { 958 if (pam_session_established) { 959 pam_err = pam_close_session(pamh, 0); 960 if (pam_err != PAM_SUCCESS) 961 pam_syslog("pam_close_session()"); 962 } 963 pam_session_established = 0; 964 if (pam_cred_established) { 965 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED); 966 if (pam_err != PAM_SUCCESS) 967 pam_syslog("pam_setcred()"); 968 } 969 pam_cred_established = 0; 970 pam_end(pamh, pam_err); 971 pamh = NULL; 972 } 973 } 974 975 /* 976 * Exit, optionally after sleeping a few seconds 977 */ 978 void 979 bail(int sec, int eval) 980 { 981 982 pam_cleanup(); 983 #ifdef USE_BSM_AUDIT 984 if (pwd != NULL) 985 audit_logout(); 986 #endif 987 sleep(sec); 988 exit(eval); 989 } 990