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 43static 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 <login_cap.h> 67#include <pwd.h> 68#include <setjmp.h> 69#include <signal.h> 70#include <stdio.h> 71#include <stdlib.h> 72#include <string.h> 73#include <syslog.h> 74#include <ttyent.h> 75#include <unistd.h> 76 77#include <security/pam_appl.h> 78#include <security/openpam.h> 79 80#include "login.h" 81#include "pathnames.h" 82 83static int auth_pam(void); 84static void bail(int, int); 85static void bail_internal(int, int, int); 86static int export(const char *); 87static void export_pam_environment(void); 88static int motd(const char *); 89static void badlogin(char *); 90static char *getloginname(void); 91static void pam_syslog(const char *); 92static void pam_cleanup(void); 93static void refused(const char *, const char *, int); 94static const char *stypeof(char *); 95static void sigint(int); 96static void timedout(int); 97static void bail_sig(int); 98static void usage(void); 99 100#define TTYGRPNAME "tty" /* group to own ttys */ 101#define DEFAULT_BACKOFF 3 102#define DEFAULT_RETRIES 10 103#define DEFAULT_PROMPT "login: " 104#define DEFAULT_PASSWD_PROMPT "Password:" 105#define TERM_UNKNOWN "su" 106#define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 107#define NO_SLEEP_EXIT 0 108#define SLEEP_EXIT 5 109 110/* 111 * This bounds the time given to login. Not a define so it can 112 * be patched on machines where it's too small. 113 */ 114static u_int timeout = 300; 115 116/* Buffer for signal handling of timeout */ 117static jmp_buf timeout_buf; 118 119struct passwd *pwd; 120static int failures; 121 122static char *envinit[1]; /* empty environment list */ 123 124/* 125 * Command line flags and arguments 126 */ 127static int fflag; /* -f: do not perform authentication */ 128static int hflag; /* -h: login from remote host */ 129static char *hostname; /* hostname from command line */ 130static int pflag; /* -p: preserve environment */ 131 132/* 133 * User name 134 */ 135static char *username; /* user name */ 136static char *olduser; /* previous user name */ 137 138/* 139 * Prompts 140 */ 141static char default_prompt[] = DEFAULT_PROMPT; 142static const char *prompt; 143static char default_passwd_prompt[] = DEFAULT_PASSWD_PROMPT; 144static const char *passwd_prompt; 145 146static char *tty; 147 148/* 149 * PAM data 150 */ 151static pam_handle_t *pamh = NULL; 152static struct pam_conv pamc = { openpam_ttyconv, NULL }; 153static int pam_err; 154static int pam_silent = PAM_SILENT; 155static int pam_cred_established; 156static int pam_session_established; 157 158int 159main(int argc, char *argv[]) 160{ 161 struct group *gr; 162 struct stat st; 163 int retries, backoff; 164 int ask, ch, cnt, quietlog, rootlogin, rval; 165 uid_t uid, euid; 166 gid_t egid; 167 char *term; 168 char *p, *ttyn; 169 char tname[sizeof(_PATH_TTY) + 10]; 170 char *arg0; 171 const char *tp; 172 const char *shell = NULL; 173 login_cap_t *lc = NULL; 174 login_cap_t *lc_user = NULL; 175 pid_t pid; 176 sigset_t mask, omask; 177 struct sigaction sa; 178#ifdef USE_BSM_AUDIT 179 char auditsuccess = 1; 180#endif 181 182 sa.sa_flags = SA_RESTART; 183 (void)sigfillset(&sa.sa_mask); 184 sa.sa_handler = SIG_IGN; 185 (void)sigaction(SIGQUIT, &sa, NULL); 186 (void)sigaction(SIGINT, &sa, NULL); 187 (void)sigaction(SIGHUP, &sa, NULL); 188 if (setjmp(timeout_buf)) { 189 if (failures) 190 badlogin(username); 191 (void)fprintf(stderr, "Login timed out after %d seconds\n", 192 timeout); 193 bail(NO_SLEEP_EXIT, 0); 194 } 195 sa.sa_handler = timedout; 196 (void)sigaction(SIGALRM, &sa, NULL); 197 (void)alarm(timeout); 198 (void)setpriority(PRIO_PROCESS, 0, 0); 199 200 openlog("login", LOG_ODELAY, LOG_AUTH); 201 202 uid = getuid(); 203 euid = geteuid(); 204 egid = getegid(); 205 206 while ((ch = getopt(argc, argv, "fh:p")) != -1) 207 switch (ch) { 208 case 'f': 209 fflag = 1; 210 break; 211 case 'h': 212 if (uid != 0) 213 errx(1, "-h option: %s", strerror(EPERM)); 214 if (strlen(optarg) >= MAXHOSTNAMELEN) 215 errx(1, "-h option: %s: exceeds maximum " 216 "hostname size", optarg); 217 hflag = 1; 218 hostname = optarg; 219 break; 220 case 'p': 221 pflag = 1; 222 break; 223 case '?': 224 default: 225 if (uid == 0) 226 syslog(LOG_ERR, "invalid flag %c", ch); 227 usage(); 228 } 229 argc -= optind; 230 argv += optind; 231 232 if (argc > 0) { 233 username = strdup(*argv); 234 if (username == NULL) 235 err(1, "strdup()"); 236 ask = 0; 237 } else { 238 ask = 1; 239 } 240 241 setproctitle("-%s", getprogname()); 242 243 closefrom(3); 244 245 /* 246 * Get current TTY 247 */ 248 ttyn = ttyname(STDIN_FILENO); 249 if (ttyn == NULL || *ttyn == '\0') { 250 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 251 ttyn = tname; 252 } 253 if (strncmp(ttyn, _PATH_DEV, sizeof _PATH_DEV - 1) == 0) 254 tty = ttyn + sizeof _PATH_DEV - 1; 255 else 256 tty = ttyn; 257 258 /* 259 * Get "login-retries" & "login-backoff" from default class 260 */ 261 lc = login_getclass(NULL); 262 prompt = login_getcapstr(lc, "login_prompt", 263 default_prompt, default_prompt); 264 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 265 default_passwd_prompt, default_passwd_prompt); 266 retries = login_getcapnum(lc, "login-retries", 267 DEFAULT_RETRIES, DEFAULT_RETRIES); 268 backoff = login_getcapnum(lc, "login-backoff", 269 DEFAULT_BACKOFF, DEFAULT_BACKOFF); 270 login_close(lc); 271 lc = NULL; 272 273 /* 274 * Try to authenticate the user until we succeed or time out. 275 */ 276 for (cnt = 0;; ask = 1) { 277 if (ask) { 278 fflag = 0; 279 if (olduser != NULL) 280 free(olduser); 281 olduser = username; 282 username = getloginname(); 283 } 284 rootlogin = 0; 285 286 /* 287 * Note if trying multiple user names; log failures for 288 * previous user name, but don't bother logging one failure 289 * for nonexistent name (mistyped username). 290 */ 291 if (failures && strcmp(olduser, username) != 0) { 292 if (failures > (pwd ? 0 : 1)) 293 badlogin(olduser); 294 } 295 296 /* 297 * Load the PAM policy and set some variables 298 */ 299 pam_err = pam_start("login", username, &pamc, &pamh); 300 if (pam_err != PAM_SUCCESS) { 301 pam_syslog("pam_start()"); 302#ifdef USE_BSM_AUDIT 303 au_login_fail("PAM Error", 1); 304#endif 305 bail(NO_SLEEP_EXIT, 1); 306 } 307 pam_err = pam_set_item(pamh, PAM_TTY, tty); 308 if (pam_err != PAM_SUCCESS) { 309 pam_syslog("pam_set_item(PAM_TTY)"); 310#ifdef USE_BSM_AUDIT 311 au_login_fail("PAM Error", 1); 312#endif 313 bail(NO_SLEEP_EXIT, 1); 314 } 315 pam_err = pam_set_item(pamh, PAM_RHOST, hostname); 316 if (pam_err != PAM_SUCCESS) { 317 pam_syslog("pam_set_item(PAM_RHOST)"); 318#ifdef USE_BSM_AUDIT 319 au_login_fail("PAM Error", 1); 320#endif 321 bail(NO_SLEEP_EXIT, 1); 322 } 323 324 pwd = getpwnam(username); 325 if (pwd != NULL && pwd->pw_uid == 0) 326 rootlogin = 1; 327 328 /* 329 * If the -f option was specified and the caller is 330 * root or the caller isn't changing their uid, don't 331 * authenticate. 332 */ 333 if (pwd != NULL && fflag && 334 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) { 335 /* already authenticated */ 336 rval = 0; 337#ifdef USE_BSM_AUDIT 338 auditsuccess = 0; /* opened a terminal window only */ 339#endif 340 } else { 341 fflag = 0; 342 (void)setpriority(PRIO_PROCESS, 0, -4); 343 rval = auth_pam(); 344 (void)setpriority(PRIO_PROCESS, 0, 0); 345 } 346 347 if (pwd && rval == 0) 348 break; 349 350 pam_cleanup(); 351 352 /* 353 * We are not exiting here, but this corresponds to a failed 354 * login event, so set exitstatus to 1. 355 */ 356#ifdef USE_BSM_AUDIT 357 au_login_fail("Login incorrect", 1); 358#endif 359 360 (void)printf("Login incorrect\n"); 361 failures++; 362 363 pwd = NULL; 364 365 /* 366 * Allow up to 'retry' (10) attempts, but start 367 * backing off after 'backoff' (3) attempts. 368 */ 369 if (++cnt > backoff) { 370 if (cnt >= retries) { 371 badlogin(username); 372 bail(SLEEP_EXIT, 1); 373 } 374 sleep((u_int)((cnt - backoff) * 5)); 375 } 376 } 377 378 /* committed to login -- turn off timeout */ 379 (void)alarm((u_int)0); 380 381 (void)sigemptyset(&mask); 382 (void)sigaddset(&mask, SIGHUP); 383 (void)sigaddset(&mask, SIGTERM); 384 (void)sigprocmask(SIG_BLOCK, &mask, &omask); 385 sa.sa_handler = bail_sig; 386 (void)sigaction(SIGHUP, &sa, NULL); 387 (void)sigaction(SIGTERM, &sa, NULL); 388 389 endpwent(); 390 391#ifdef USE_BSM_AUDIT 392 /* Audit successful login. */ 393 if (auditsuccess) 394 au_login_success(); 395#endif 396 397 /* 398 * This needs to happen before login_getpwclass to support 399 * home directories on GSS-API authenticated NFS where the 400 * kerberos credentials need to be saved so that the kernel 401 * can authenticate to the NFS server. 402 */ 403 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED); 404 if (pam_err != PAM_SUCCESS) { 405 pam_syslog("pam_setcred()"); 406 bail(NO_SLEEP_EXIT, 1); 407 } 408 pam_cred_established = 1; 409 410 /* 411 * Establish the login class. 412 */ 413 lc = login_getpwclass(pwd); 414 lc_user = login_getuserclass(pwd); 415 416 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0))) 417 quietlog = login_getcapbool(lc, "hushlogin", 0); 418 419 /* 420 * Switching needed for NFS with root access disabled. 421 * 422 * XXX: This change fails to modify the additional groups for the 423 * process, and as such, may restrict rights normally granted 424 * through those groups. 425 */ 426 (void)setegid(pwd->pw_gid); 427 (void)seteuid(rootlogin ? 0 : pwd->pw_uid); 428 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 429 if (login_getcapbool(lc, "requirehome", 0)) 430 refused("Home directory not available", "HOMEDIR", 1); 431 if (chdir("/") < 0) 432 refused("Cannot find root directory", "ROOTDIR", 1); 433 if (!quietlog || *pwd->pw_dir) 434 printf("No home directory.\nLogging in with home = \"/\".\n"); 435 pwd->pw_dir = strdup("/"); 436 if (pwd->pw_dir == NULL) { 437 syslog(LOG_NOTICE, "strdup(): %m"); 438 bail(SLEEP_EXIT, 1); 439 } 440 } 441 (void)seteuid(euid); 442 (void)setegid(egid); 443 if (!quietlog) { 444 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 445 if (!quietlog) 446 pam_silent = 0; 447 } 448 449 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 450 if (*pwd->pw_shell == '\0') 451 pwd->pw_shell = strdup(_PATH_BSHELL); 452 if (pwd->pw_shell == NULL) { 453 syslog(LOG_NOTICE, "strdup(): %m"); 454 bail(SLEEP_EXIT, 1); 455 } 456 if (*shell == '\0') /* Not overridden */ 457 shell = pwd->pw_shell; 458 if ((shell = strdup(shell)) == NULL) { 459 syslog(LOG_NOTICE, "strdup(): %m"); 460 bail(SLEEP_EXIT, 1); 461 } 462 463 /* 464 * Set device protections, depending on what terminal the 465 * user is logged in. This feature is used on Suns to give 466 * console users better privacy. 467 */ 468 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 469 470 /* 471 * Clear flags of the tty. None should be set, and when the 472 * user sets them otherwise, this can cause the chown to fail. 473 * Since it isn't clear that flags are useful on character 474 * devices, we just clear them. 475 * 476 * We don't log in the case of EOPNOTSUPP because dev might be 477 * on NFS, which doesn't support chflags. 478 * 479 * We don't log in the EROFS because that means that /dev is on 480 * a read only file system and we assume that the permissions there 481 * are sane. 482 */ 483 if (ttyn != tname && chflags(ttyn, 0)) 484 if (errno != EOPNOTSUPP && errno != EROFS) 485 syslog(LOG_ERR, "chflags(%s): %m", ttyn); 486 if (ttyn != tname && chown(ttyn, pwd->pw_uid, 487 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 488 if (errno != EROFS) 489 syslog(LOG_ERR, "chown(%s): %m", ttyn); 490 491 /* 492 * Exclude cons/vt/ptys only, assume dialup otherwise 493 * TODO: Make dialup tty determination a library call 494 * for consistency (finger etc.) 495 */ 496 if (hflag && isdialuptty(tty)) 497 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 498 499#ifdef LOGALL 500 /* 501 * Syslog each successful login, so we don't have to watch 502 * hundreds of wtmp or lastlogin files. 503 */ 504 if (hflag) 505 syslog(LOG_INFO, "login from %s on %s as %s", 506 hostname, tty, pwd->pw_name); 507 else 508 syslog(LOG_INFO, "login on %s as %s", 509 tty, pwd->pw_name); 510#endif 511 512 /* 513 * If fflag is on, assume caller/authenticator has logged root 514 * login. 515 */ 516 if (rootlogin && fflag == 0) { 517 if (hflag) 518 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 519 username, tty, hostname); 520 else 521 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 522 username, tty); 523 } 524 525 /* 526 * Destroy environment unless user has requested its 527 * preservation - but preserve TERM in all cases 528 */ 529 term = getenv("TERM"); 530 if (!pflag) 531 environ = envinit; 532 if (term != NULL) 533 setenv("TERM", term, 0); 534 535 /* 536 * PAM modules might add supplementary groups during pam_setcred(). 537 */ 538 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 539 syslog(LOG_ERR, "setusercontext() failed - exiting"); 540 bail(NO_SLEEP_EXIT, 1); 541 } 542 543 pam_err = pam_setcred(pamh, pam_silent|PAM_REINITIALIZE_CRED); 544 if (pam_err != PAM_SUCCESS) { 545 pam_syslog("pam_setcred()"); 546 bail(NO_SLEEP_EXIT, 1); 547 } 548 549 pam_err = pam_open_session(pamh, pam_silent); 550 if (pam_err != PAM_SUCCESS) { 551 pam_syslog("pam_open_session()"); 552 bail(NO_SLEEP_EXIT, 1); 553 } 554 pam_session_established = 1; 555 556 /* 557 * We must fork() before setuid() because we need to call 558 * pam_close_session() as root. 559 */ 560 pid = fork(); 561 if (pid < 0) { 562 err(1, "fork"); 563 } else if (pid != 0) { 564 /* 565 * Parent: wait for child to finish, then clean up 566 * session. 567 * 568 * If we get SIGHUP or SIGTERM, clean up the session 569 * and exit right away. This will make the terminal 570 * inaccessible and send SIGHUP to the foreground 571 * process group. 572 */ 573 int status; 574 setproctitle("-%s [pam]", getprogname()); 575 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 576 waitpid(pid, &status, 0); 577 (void)sigprocmask(SIG_BLOCK, &mask, NULL); 578 bail(NO_SLEEP_EXIT, 0); 579 } 580 581 /* 582 * NOTICE: We are now in the child process! 583 */ 584 585 /* 586 * Add any environment variables the PAM modules may have set. 587 */ 588 export_pam_environment(); 589 590 /* 591 * We're done with PAM now; our parent will deal with the rest. 592 */ 593 pam_end(pamh, 0); 594 pamh = NULL; 595 596 /* 597 * We don't need to be root anymore, so set the login name and 598 * the UID. 599 */ 600 if (setlogin(username) != 0) { 601 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 602 bail(NO_SLEEP_EXIT, 1); 603 } 604 if (setusercontext(lc, pwd, pwd->pw_uid, 605 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 606 syslog(LOG_ERR, "setusercontext() failed - exiting"); 607 exit(1); 608 } 609 610 (void)setenv("SHELL", pwd->pw_shell, 1); 611 (void)setenv("HOME", pwd->pw_dir, 1); 612 /* Overwrite "term" from login.conf(5) for any known TERM */ 613 if (term == NULL && (tp = stypeof(tty)) != NULL) 614 (void)setenv("TERM", tp, 1); 615 else 616 (void)setenv("TERM", TERM_UNKNOWN, 0); 617 (void)setenv("LOGNAME", username, 1); 618 (void)setenv("USER", username, 1); 619 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0); 620 621 if (!quietlog) { 622 const char *cw; 623 624 cw = login_getcapstr(lc, "welcome", NULL, NULL); 625 if (cw != NULL && access(cw, F_OK) == 0) 626 motd(cw); 627 else 628 motd(_PATH_MOTDFILE); 629 630 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 && 631 login_getcapbool(lc, "nocheckmail", 0) == 0) { 632 char *cx; 633 634 /* $MAIL may have been set by class. */ 635 cx = getenv("MAIL"); 636 if (cx == NULL) { 637 asprintf(&cx, "%s/%s", 638 _PATH_MAILDIR, pwd->pw_name); 639 } 640 if (cx && stat(cx, &st) == 0 && st.st_size != 0) 641 (void)printf("You have %smail.\n", 642 (st.st_mtime > st.st_atime) ? "new " : ""); 643 if (getenv("MAIL") == NULL) 644 free(cx); 645 } 646 } 647 648 login_close(lc_user); 649 login_close(lc); 650 651 sa.sa_handler = SIG_DFL; 652 (void)sigaction(SIGALRM, &sa, NULL); 653 (void)sigaction(SIGQUIT, &sa, NULL); 654 (void)sigaction(SIGINT, &sa, NULL); 655 (void)sigaction(SIGTERM, &sa, NULL); 656 (void)sigaction(SIGHUP, &sa, NULL); 657 sa.sa_handler = SIG_IGN; 658 (void)sigaction(SIGTSTP, &sa, NULL); 659 (void)sigprocmask(SIG_SETMASK, &omask, NULL); 660 661 /* 662 * Login shells have a leading '-' in front of argv[0] 663 */ 664 p = strrchr(pwd->pw_shell, '/'); 665 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) { 666 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 667 username); 668 errx(1, "shell exceeds maximum pathname size"); 669 } else if (arg0 == NULL) { 670 err(1, "asprintf()"); 671 } 672 673 execlp(shell, arg0, (char *)0); 674 err(1, "%s", shell); 675 676 /* 677 * That's it, folks! 678 */ 679} 680 681/* 682 * Attempt to authenticate the user using PAM. Returns 0 if the user is 683 * authenticated, or 1 if not authenticated. If some sort of PAM system 684 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 685 * function returns -1. This can be used as an indication that we should 686 * fall back to a different authentication mechanism. 687 */ 688static int 689auth_pam(void) 690{ 691 const char *tmpl_user; 692 const void *item; 693 int rval; 694 695 pam_err = pam_authenticate(pamh, pam_silent); 696 switch (pam_err) { 697 698 case PAM_SUCCESS: 699 /* 700 * With PAM we support the concept of a "template" 701 * user. The user enters a login name which is 702 * authenticated by PAM, usually via a remote service 703 * such as RADIUS or TACACS+. If authentication 704 * succeeds, a different but related "template" name 705 * is used for setting the credentials, shell, and 706 * home directory. The name the user enters need only 707 * exist on the remote authentication server, but the 708 * template name must be present in the local password 709 * database. 710 * 711 * This is supported by two various mechanisms in the 712 * individual modules. However, from the application's 713 * point of view, the template user is always passed 714 * back as a changed value of the PAM_USER item. 715 */ 716 pam_err = pam_get_item(pamh, PAM_USER, &item); 717 if (pam_err == PAM_SUCCESS) { 718 tmpl_user = (const char *)item; 719 if (strcmp(username, tmpl_user) != 0) 720 pwd = getpwnam(tmpl_user); 721 } else { 722 pam_syslog("pam_get_item(PAM_USER)"); 723 } 724 rval = 0; 725 break; 726 727 case PAM_AUTH_ERR: 728 case PAM_USER_UNKNOWN: 729 case PAM_MAXTRIES: 730 rval = 1; 731 break; 732 733 default: 734 pam_syslog("pam_authenticate()"); 735 rval = -1; 736 break; 737 } 738 739 if (rval == 0) { 740 pam_err = pam_acct_mgmt(pamh, pam_silent); 741 switch (pam_err) { 742 case PAM_SUCCESS: 743 break; 744 case PAM_NEW_AUTHTOK_REQD: 745 pam_err = pam_chauthtok(pamh, 746 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK); 747 if (pam_err != PAM_SUCCESS) { 748 pam_syslog("pam_chauthtok()"); 749 rval = 1; 750 } 751 break; 752 default: 753 pam_syslog("pam_acct_mgmt()"); 754 rval = 1; 755 break; 756 } 757 } 758 759 if (rval != 0) { 760 pam_end(pamh, pam_err); 761 pamh = NULL; 762 } 763 return (rval); 764} 765 766/* 767 * Export any environment variables PAM modules may have set 768 */ 769static void 770export_pam_environment(void) 771{ 772 char **pam_env; 773 char **pp; 774 775 pam_env = pam_getenvlist(pamh); 776 if (pam_env != NULL) { 777 for (pp = pam_env; *pp != NULL; pp++) { 778 (void)export(*pp); 779 free(*pp); 780 } 781 } 782} 783 784/* 785 * Perform sanity checks on an environment variable: 786 * - Make sure there is an '=' in the string. 787 * - Make sure the string doesn't run on too long. 788 * - Do not export certain variables. This list was taken from the 789 * Solaris pam_putenv(3) man page. 790 * Then export it. 791 */ 792static int 793export(const char *s) 794{ 795 static const char *noexport[] = { 796 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 797 "IFS", "PATH", NULL 798 }; 799 char *p; 800 const char **pp; 801 size_t n; 802 803 if (strlen(s) > 1024 || (p = strchr(s, '=')) == NULL) 804 return (0); 805 if (strncmp(s, "LD_", 3) == 0) 806 return (0); 807 for (pp = noexport; *pp != NULL; pp++) { 808 n = strlen(*pp); 809 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 810 return (0); 811 } 812 *p = '\0'; 813 (void)setenv(s, p + 1, 1); 814 *p = '='; 815 return (1); 816} 817 818static void 819usage(void) 820{ 821 822 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 823 exit(1); 824} 825 826/* 827 * Prompt user and read login name from stdin. 828 */ 829static char * 830getloginname(void) 831{ 832 char *nbuf, *p; 833 int ch; 834 835 nbuf = malloc(MAXLOGNAME); 836 if (nbuf == NULL) 837 err(1, "malloc()"); 838 do { 839 (void)printf("%s", prompt); 840 for (p = nbuf; (ch = getchar()) != '\n'; ) { 841 if (ch == EOF) { 842 badlogin(username); 843 bail(NO_SLEEP_EXIT, 0); 844 } 845 if (p < nbuf + MAXLOGNAME - 1) 846 *p++ = ch; 847 } 848 } while (p == nbuf); 849 850 *p = '\0'; 851 if (nbuf[0] == '-') { 852 pam_silent = 0; 853 memmove(nbuf, nbuf + 1, strlen(nbuf)); 854 } else { 855 pam_silent = PAM_SILENT; 856 } 857 return nbuf; 858} 859 860/* 861 * SIGINT handler for motd(). 862 */ 863static volatile int motdinterrupt; 864static void 865sigint(int signo __unused) 866{ 867 motdinterrupt = 1; 868} 869 870/* 871 * Display the contents of a file (such as /etc/motd). 872 */ 873static int 874motd(const char *motdfile) 875{ 876 struct sigaction newint, oldint; 877 FILE *f; 878 int ch; 879 880 if ((f = fopen(motdfile, "r")) == NULL) 881 return (-1); 882 motdinterrupt = 0; 883 newint.sa_handler = sigint; 884 newint.sa_flags = 0; 885 sigfillset(&newint.sa_mask); 886 sigaction(SIGINT, &newint, &oldint); 887 while ((ch = fgetc(f)) != EOF && !motdinterrupt) 888 putchar(ch); 889 sigaction(SIGINT, &oldint, NULL); 890 if (ch != EOF || ferror(f)) { 891 fclose(f); 892 return (-1); 893 } 894 fclose(f); 895 return (0); 896} 897 898/* 899 * SIGALRM handler, to enforce login prompt timeout. 900 * 901 * XXX This can potentially confuse the hell out of PAM. We should 902 * XXX instead implement a conversation function that returns 903 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal 904 * XXX handler just set a flag. 905 */ 906static void 907timedout(int signo __unused) 908{ 909 910 longjmp(timeout_buf, signo); 911} 912 913static void 914badlogin(char *name) 915{ 916 917 if (failures == 0) 918 return; 919 if (hflag) { 920 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 921 failures, failures > 1 ? "S" : "", hostname); 922 syslog(LOG_AUTHPRIV|LOG_NOTICE, 923 "%d LOGIN FAILURE%s FROM %s, %s", 924 failures, failures > 1 ? "S" : "", hostname, name); 925 } else { 926 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 927 failures, failures > 1 ? "S" : "", tty); 928 syslog(LOG_AUTHPRIV|LOG_NOTICE, 929 "%d LOGIN FAILURE%s ON %s, %s", 930 failures, failures > 1 ? "S" : "", tty, name); 931 } 932 failures = 0; 933} 934 935const char * 936stypeof(char *ttyid) 937{ 938 struct ttyent *t; 939 940 if (ttyid != NULL && *ttyid != '\0') { 941 t = getttynam(ttyid); 942 if (t != NULL && t->ty_type != NULL) 943 return (t->ty_type); 944 } 945 return (NULL); 946} 947 948static void 949refused(const char *msg, const char *rtype, int lout) 950{ 951 952 if (msg != NULL) 953 printf("%s.\n", msg); 954 if (hflag) 955 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 956 pwd->pw_name, rtype, hostname, tty); 957 else 958 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 959 pwd->pw_name, rtype, tty); 960 if (lout) 961 bail(SLEEP_EXIT, 1); 962} 963 964/* 965 * Log a PAM error 966 */ 967static void 968pam_syslog(const char *msg) 969{ 970 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err)); 971} 972 973/* 974 * Shut down PAM 975 */ 976static void 977pam_cleanup(void) 978{ 979 980 if (pamh != NULL) { 981 if (pam_session_established) { 982 pam_err = pam_close_session(pamh, 0); 983 if (pam_err != PAM_SUCCESS) 984 pam_syslog("pam_close_session()"); 985 } 986 pam_session_established = 0; 987 if (pam_cred_established) { 988 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED); 989 if (pam_err != PAM_SUCCESS) 990 pam_syslog("pam_setcred()"); 991 } 992 pam_cred_established = 0; 993 pam_end(pamh, pam_err); 994 pamh = NULL; 995 } 996} 997 998static void 999bail_internal(int sec, int eval, int signo) 1000{ 1001 struct sigaction sa; 1002 1003 pam_cleanup(); 1004#ifdef USE_BSM_AUDIT 1005 if (pwd != NULL) 1006 audit_logout(); 1007#endif 1008 (void)sleep(sec); 1009 if (signo == 0) 1010 exit(eval); 1011 else { 1012 sa.sa_handler = SIG_DFL; 1013 sa.sa_flags = 0; 1014 (void)sigemptyset(&sa.sa_mask); 1015 (void)sigaction(signo, &sa, NULL); 1016 (void)sigaddset(&sa.sa_mask, signo); 1017 (void)sigprocmask(SIG_UNBLOCK, &sa.sa_mask, NULL); 1018 raise(signo); 1019 exit(128 + signo); 1020 } 1021} 1022 1023/* 1024 * Exit, optionally after sleeping a few seconds 1025 */ 1026static void 1027bail(int sec, int eval) 1028{ 1029 bail_internal(sec, eval, 0); 1030} 1031 1032/* 1033 * Exit because of a signal. 1034 * This is not async-signal safe, so only call async-signal safe functions 1035 * while the signal is unmasked. 1036 */ 1037static void 1038bail_sig(int signo) 1039{ 1040 bail_internal(NO_SLEEP_EXIT, 0, signo); 1041} 1042