login.c revision 146867
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: head/usr.bin/login/login.c 146867 2005-06-01 12:23:06Z maxim $"); 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/copyright.h> 57#include <sys/param.h> 58#include <sys/file.h> 59#include <sys/stat.h> 60#include <sys/time.h> 61#include <sys/resource.h> 62#include <sys/wait.h> 63 64#include <err.h> 65#include <errno.h> 66#include <grp.h> 67#include <libutil.h> 68#include <login_cap.h> 69#include <pwd.h> 70#include <setjmp.h> 71#include <signal.h> 72#include <stdio.h> 73#include <stdlib.h> 74#include <string.h> 75#include <syslog.h> 76#include <ttyent.h> 77#include <unistd.h> 78 79#include <security/pam_appl.h> 80#include <security/openpam.h> 81 82#include "login.h" 83#include "pathnames.h" 84 85static int auth_pam(void); 86static void bail(int, int); 87static int export(const char *); 88static void export_pam_environment(void); 89static int motd(const char *); 90static void badlogin(char *); 91static char *getloginname(void); 92static void pam_syslog(const char *); 93static void pam_cleanup(void); 94static void refused(const char *, const char *, int); 95static const char *stypeof(char *); 96static void sigint(int); 97static void timedout(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; 176 177 (void)signal(SIGQUIT, SIG_IGN); 178 (void)signal(SIGINT, SIG_IGN); 179 (void)signal(SIGHUP, SIG_IGN); 180 if (setjmp(timeout_buf)) { 181 if (failures) 182 badlogin(username); 183 (void)fprintf(stderr, "Login timed out after %d seconds\n", 184 timeout); 185 bail(NO_SLEEP_EXIT, 0); 186 } 187 (void)signal(SIGALRM, timedout); 188 (void)alarm(timeout); 189 (void)setpriority(PRIO_PROCESS, 0, 0); 190 191 openlog("login", LOG_ODELAY, LOG_AUTH); 192 193 uid = getuid(); 194 euid = geteuid(); 195 egid = getegid(); 196 197 while ((ch = getopt(argc, argv, "fh:p")) != -1) 198 switch (ch) { 199 case 'f': 200 fflag = 1; 201 break; 202 case 'h': 203 if (uid != 0) 204 errx(1, "-h option: %s", strerror(EPERM)); 205 if (strlen(optarg) >= MAXHOSTNAMELEN) 206 errx(1, "-h option: %s: exceeds maximum " 207 "hostname size", optarg); 208 hflag = 1; 209 hostname = optarg; 210 break; 211 case 'p': 212 pflag = 1; 213 break; 214 case '?': 215 default: 216 if (uid == 0) 217 syslog(LOG_ERR, "invalid flag %c", ch); 218 usage(); 219 } 220 argc -= optind; 221 argv += optind; 222 223 if (argc > 0) { 224 username = strdup(*argv); 225 if (username == NULL) 226 err(1, "strdup()"); 227 ask = 0; 228 } else { 229 ask = 1; 230 } 231 232 setproctitle("-%s", getprogname()); 233 234 for (cnt = getdtablesize(); cnt > 2; cnt--) 235 (void)close(cnt); 236 237 /* 238 * Get current TTY 239 */ 240 ttyn = ttyname(STDIN_FILENO); 241 if (ttyn == NULL || *ttyn == '\0') { 242 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 243 ttyn = tname; 244 } 245 if ((tty = strrchr(ttyn, '/')) != NULL) 246 ++tty; 247 else 248 tty = ttyn; 249 250 /* 251 * Get "login-retries" & "login-backoff" from default class 252 */ 253 lc = login_getclass(NULL); 254 prompt = login_getcapstr(lc, "login_prompt", 255 default_prompt, default_prompt); 256 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 257 default_passwd_prompt, default_passwd_prompt); 258 retries = login_getcapnum(lc, "login-retries", 259 DEFAULT_RETRIES, DEFAULT_RETRIES); 260 backoff = login_getcapnum(lc, "login-backoff", 261 DEFAULT_BACKOFF, DEFAULT_BACKOFF); 262 login_close(lc); 263 lc = NULL; 264 265 /* 266 * Try to authenticate the user until we succeed or time out. 267 */ 268 for (cnt = 0;; ask = 1) { 269 if (ask) { 270 fflag = 0; 271 if (olduser != NULL) 272 free(olduser); 273 olduser = username; 274 username = getloginname(); 275 } 276 rootlogin = 0; 277 278 /* 279 * Note if trying multiple user names; log failures for 280 * previous user name, but don't bother logging one failure 281 * for nonexistent name (mistyped username). 282 */ 283 if (failures && strcmp(olduser, username) != 0) { 284 if (failures > (pwd ? 0 : 1)) 285 badlogin(olduser); 286 } 287 288 /* 289 * Load the PAM policy and set some variables 290 */ 291 pam_err = pam_start("login", username, &pamc, &pamh); 292 if (pam_err != PAM_SUCCESS) { 293 pam_syslog("pam_start()"); 294 bail(NO_SLEEP_EXIT, 1); 295 } 296 pam_err = pam_set_item(pamh, PAM_TTY, tty); 297 if (pam_err != PAM_SUCCESS) { 298 pam_syslog("pam_set_item(PAM_TTY)"); 299 bail(NO_SLEEP_EXIT, 1); 300 } 301 pam_err = pam_set_item(pamh, PAM_RHOST, hostname); 302 if (pam_err != PAM_SUCCESS) { 303 pam_syslog("pam_set_item(PAM_RHOST)"); 304 bail(NO_SLEEP_EXIT, 1); 305 } 306 307 pwd = getpwnam(username); 308 if (pwd != NULL && pwd->pw_uid == 0) 309 rootlogin = 1; 310 311 /* 312 * If the -f option was specified and the caller is 313 * root or the caller isn't changing their uid, don't 314 * authenticate. 315 */ 316 if (pwd != NULL && fflag && 317 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) { 318 /* already authenticated */ 319 rval = 0; 320 } else { 321 fflag = 0; 322 (void)setpriority(PRIO_PROCESS, 0, -4); 323 rval = auth_pam(); 324 (void)setpriority(PRIO_PROCESS, 0, 0); 325 } 326 327 if (pwd && rval == 0) 328 break; 329 330 pam_cleanup(); 331 332 (void)printf("Login incorrect\n"); 333 failures++; 334 335 /* 336 * Allow up to 'retry' (10) attempts, but start 337 * backing off after 'backoff' (3) attempts. 338 */ 339 if (++cnt > backoff) { 340 if (cnt >= retries) { 341 badlogin(username); 342 bail(SLEEP_EXIT, 1); 343 } 344 sleep((u_int)((cnt - backoff) * 5)); 345 } 346 } 347 348 /* committed to login -- turn off timeout */ 349 (void)alarm((u_int)0); 350 (void)signal(SIGHUP, SIG_DFL); 351 352 endpwent(); 353 354 /* 355 * Establish the login class. 356 */ 357 lc = login_getpwclass(pwd); 358 lc_user = login_getuserclass(pwd); 359 360 if (!(quietlog = login_getcapbool(lc_user, "hushlogin", 0))) 361 quietlog = login_getcapbool(lc, "hushlogin", 0); 362 363 /* 364 * Switching needed for NFS with root access disabled. 365 * 366 * XXX: This change fails to modify the additional groups for the 367 * process, and as such, may restrict rights normally granted 368 * through those groups. 369 */ 370 (void)setegid(pwd->pw_gid); 371 (void)seteuid(rootlogin ? 0 : pwd->pw_uid); 372 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 373 if (login_getcapbool(lc, "requirehome", 0)) 374 refused("Home directory not available", "HOMEDIR", 1); 375 if (chdir("/") < 0) 376 refused("Cannot find root directory", "ROOTDIR", 1); 377 if (!quietlog || *pwd->pw_dir) 378 printf("No home directory.\nLogging in with home = \"/\".\n"); 379 pwd->pw_dir = strdup("/"); 380 if (pwd->pw_dir == NULL) { 381 syslog(LOG_NOTICE, "strdup(): %m"); 382 bail(SLEEP_EXIT, 1); 383 } 384 } 385 (void)seteuid(euid); 386 (void)setegid(egid); 387 if (!quietlog) { 388 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 389 if (!quietlog) 390 pam_silent = 0; 391 } 392 393 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 394 if (*pwd->pw_shell == '\0') 395 pwd->pw_shell = strdup(_PATH_BSHELL); 396 if (pwd->pw_shell == NULL) { 397 syslog(LOG_NOTICE, "strdup(): %m"); 398 bail(SLEEP_EXIT, 1); 399 } 400 if (*shell == '\0') /* Not overridden */ 401 shell = pwd->pw_shell; 402 if ((shell = strdup(shell)) == NULL) { 403 syslog(LOG_NOTICE, "strdup(): %m"); 404 bail(SLEEP_EXIT, 1); 405 } 406 407 /* 408 * Set device protections, depending on what terminal the 409 * user is logged in. This feature is used on Suns to give 410 * console users better privacy. 411 */ 412 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 413 414 /* 415 * Clear flags of the tty. None should be set, and when the 416 * user sets them otherwise, this can cause the chown to fail. 417 * Since it isn't clear that flags are useful on character 418 * devices, we just clear them. 419 * 420 * We don't log in the case of EOPNOTSUPP because dev might be 421 * on NFS, which doesn't support chflags. 422 * 423 * We don't log in the EROFS because that means that /dev is on 424 * a read only file system and we assume that the permissions there 425 * are sane. 426 */ 427 if (ttyn != tname && chflags(ttyn, 0)) 428 if (errno != EOPNOTSUPP && errno != EROFS) 429 syslog(LOG_ERR, "chflags(%s): %m", ttyn); 430 if (ttyn != tname && chown(ttyn, pwd->pw_uid, 431 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 432 if (errno != EROFS) 433 syslog(LOG_ERR, "chown(%s): %m", ttyn); 434 435 /* 436 * Exclude cons/vt/ptys only, assume dialup otherwise 437 * TODO: Make dialup tty determination a library call 438 * for consistency (finger etc.) 439 */ 440 if (hflag && isdialuptty(tty)) 441 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 442 443#ifdef LOGALL 444 /* 445 * Syslog each successful login, so we don't have to watch 446 * hundreds of wtmp or lastlogin files. 447 */ 448 if (hflag) 449 syslog(LOG_INFO, "login from %s on %s as %s", 450 hostname, tty, pwd->pw_name); 451 else 452 syslog(LOG_INFO, "login on %s as %s", 453 tty, pwd->pw_name); 454#endif 455 456 /* 457 * If fflag is on, assume caller/authenticator has logged root 458 * login. 459 */ 460 if (rootlogin && fflag == 0) { 461 if (hflag) 462 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 463 username, tty, hostname); 464 else 465 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 466 username, tty); 467 } 468 469 /* 470 * Destroy environment unless user has requested its 471 * preservation - but preserve TERM in all cases 472 */ 473 term = getenv("TERM"); 474 if (!pflag) 475 environ = envinit; 476 if (term != NULL) 477 setenv("TERM", term, 0); 478 479 /* 480 * PAM modules might add supplementary groups during pam_setcred(). 481 */ 482 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 483 syslog(LOG_ERR, "setusercontext() failed - exiting"); 484 bail(NO_SLEEP_EXIT, 1); 485 } 486 487 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED); 488 if (pam_err != PAM_SUCCESS) { 489 pam_syslog("pam_setcred()"); 490 bail(NO_SLEEP_EXIT, 1); 491 } 492 pam_cred_established = 1; 493 494 pam_err = pam_open_session(pamh, pam_silent); 495 if (pam_err != PAM_SUCCESS) { 496 pam_syslog("pam_open_session()"); 497 bail(NO_SLEEP_EXIT, 1); 498 } 499 pam_session_established = 1; 500 501 /* 502 * We must fork() before setuid() because we need to call 503 * pam_close_session() as root. 504 */ 505 pid = fork(); 506 if (pid < 0) { 507 err(1, "fork"); 508 } else if (pid != 0) { 509 /* 510 * Parent: wait for child to finish, then clean up 511 * session. 512 */ 513 int status; 514 setproctitle("-%s [pam]", getprogname()); 515 waitpid(pid, &status, 0); 516 bail(NO_SLEEP_EXIT, 0); 517 } 518 519 /* 520 * NOTICE: We are now in the child process! 521 */ 522 523 /* 524 * Add any environment variables the PAM modules may have set. 525 */ 526 export_pam_environment(); 527 528 /* 529 * We're done with PAM now; our parent will deal with the rest. 530 */ 531 pam_end(pamh, 0); 532 pamh = NULL; 533 534 /* 535 * We don't need to be root anymore, so set the login name and 536 * the UID. 537 */ 538 if (setlogin(username) != 0) { 539 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 540 bail(NO_SLEEP_EXIT, 1); 541 } 542 if (setusercontext(lc, pwd, pwd->pw_uid, 543 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 544 syslog(LOG_ERR, "setusercontext() failed - exiting"); 545 exit(1); 546 } 547 548 (void)setenv("SHELL", pwd->pw_shell, 1); 549 (void)setenv("HOME", pwd->pw_dir, 1); 550 /* Overwrite "term" from login.conf(5) for any known TERM */ 551 if (term == NULL && (tp = stypeof(tty)) != NULL) 552 (void)setenv("TERM", tp, 1); 553 else 554 (void)setenv("TERM", TERM_UNKNOWN, 0); 555 (void)setenv("LOGNAME", username, 1); 556 (void)setenv("USER", username, 1); 557 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0); 558 559 if (!quietlog) { 560 const char *cw; 561 562 cw = login_getcapstr(lc, "copyright", NULL, NULL); 563 if (cw == NULL || motd(cw) == -1) 564 (void)printf("%s", copyright); 565 566 (void)printf("\n"); 567 568 cw = login_getcapstr(lc, "welcome", NULL, NULL); 569 if (cw != NULL && access(cw, F_OK) == 0) 570 motd(cw); 571 else 572 motd(_PATH_MOTDFILE); 573 574 if (login_getcapbool(lc_user, "nocheckmail", 0) == 0 && 575 login_getcapbool(lc, "nocheckmail", 0) == 0) { 576 char *cx; 577 578 /* $MAIL may have been set by class. */ 579 cx = getenv("MAIL"); 580 if (cx == NULL) { 581 asprintf(&cx, "%s/%s", 582 _PATH_MAILDIR, pwd->pw_name); 583 } 584 if (cx && stat(cx, &st) == 0 && st.st_size != 0) 585 (void)printf("You have %smail.\n", 586 (st.st_mtime > st.st_atime) ? "new " : ""); 587 if (getenv("MAIL") == NULL) 588 free(cx); 589 } 590 } 591 592 login_close(lc_user); 593 login_close(lc); 594 595 (void)signal(SIGALRM, SIG_DFL); 596 (void)signal(SIGQUIT, SIG_DFL); 597 (void)signal(SIGINT, SIG_DFL); 598 (void)signal(SIGTSTP, SIG_IGN); 599 600 /* 601 * Login shells have a leading '-' in front of argv[0] 602 */ 603 p = strrchr(pwd->pw_shell, '/'); 604 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) { 605 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 606 username); 607 errx(1, "shell exceeds maximum pathname size"); 608 } else if (arg0 == NULL) { 609 err(1, "asprintf()"); 610 } 611 612 execlp(shell, arg0, (char *)0); 613 err(1, "%s", shell); 614 615 /* 616 * That's it, folks! 617 */ 618} 619 620/* 621 * Attempt to authenticate the user using PAM. Returns 0 if the user is 622 * authenticated, or 1 if not authenticated. If some sort of PAM system 623 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 624 * function returns -1. This can be used as an indication that we should 625 * fall back to a different authentication mechanism. 626 */ 627static int 628auth_pam(void) 629{ 630 const char *tmpl_user; 631 const void *item; 632 int rval; 633 634 pam_err = pam_authenticate(pamh, pam_silent); 635 switch (pam_err) { 636 637 case PAM_SUCCESS: 638 /* 639 * With PAM we support the concept of a "template" 640 * user. The user enters a login name which is 641 * authenticated by PAM, usually via a remote service 642 * such as RADIUS or TACACS+. If authentication 643 * succeeds, a different but related "template" name 644 * is used for setting the credentials, shell, and 645 * home directory. The name the user enters need only 646 * exist on the remote authentication server, but the 647 * template name must be present in the local password 648 * database. 649 * 650 * This is supported by two various mechanisms in the 651 * individual modules. However, from the application's 652 * point of view, the template user is always passed 653 * back as a changed value of the PAM_USER item. 654 */ 655 pam_err = pam_get_item(pamh, PAM_USER, &item); 656 if (pam_err == PAM_SUCCESS) { 657 tmpl_user = (const char *)item; 658 if (strcmp(username, tmpl_user) != 0) 659 pwd = getpwnam(tmpl_user); 660 } else { 661 pam_syslog("pam_get_item(PAM_USER)"); 662 } 663 rval = 0; 664 break; 665 666 case PAM_AUTH_ERR: 667 case PAM_USER_UNKNOWN: 668 case PAM_MAXTRIES: 669 rval = 1; 670 break; 671 672 default: 673 pam_syslog("pam_authenticate()"); 674 rval = -1; 675 break; 676 } 677 678 if (rval == 0) { 679 pam_err = pam_acct_mgmt(pamh, pam_silent); 680 switch (pam_err) { 681 case PAM_SUCCESS: 682 break; 683 case PAM_NEW_AUTHTOK_REQD: 684 pam_err = pam_chauthtok(pamh, 685 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK); 686 if (pam_err != PAM_SUCCESS) { 687 pam_syslog("pam_chauthtok()"); 688 rval = 1; 689 } 690 break; 691 default: 692 pam_syslog("pam_acct_mgmt()"); 693 rval = 1; 694 break; 695 } 696 } 697 698 if (rval != 0) { 699 pam_end(pamh, pam_err); 700 pamh = NULL; 701 } 702 return (rval); 703} 704 705/* 706 * Export any environment variables PAM modules may have set 707 */ 708static void 709export_pam_environment() 710{ 711 char **pam_env; 712 char **pp; 713 714 pam_env = pam_getenvlist(pamh); 715 if (pam_env != NULL) { 716 for (pp = pam_env; *pp != NULL; pp++) { 717 (void)export(*pp); 718 free(*pp); 719 } 720 } 721} 722 723/* 724 * Perform sanity checks on an environment variable: 725 * - Make sure there is an '=' in the string. 726 * - Make sure the string doesn't run on too long. 727 * - Do not export certain variables. This list was taken from the 728 * Solaris pam_putenv(3) man page. 729 * Then export it. 730 */ 731static int 732export(const char *s) 733{ 734 static const char *noexport[] = { 735 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 736 "IFS", "PATH", NULL 737 }; 738 const char **pp; 739 size_t n; 740 741 if (strlen(s) > 1024 || strchr(s, '=') == NULL) 742 return (0); 743 if (strncmp(s, "LD_", 3) == 0) 744 return (0); 745 for (pp = noexport; *pp != NULL; pp++) { 746 n = strlen(*pp); 747 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 748 return (0); 749 } 750 (void)putenv(s); 751 return (1); 752} 753 754static void 755usage() 756{ 757 758 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 759 exit(1); 760} 761 762/* 763 * Prompt user and read login name from stdin. 764 */ 765static char * 766getloginname() 767{ 768 char *nbuf, *p; 769 int ch; 770 771 nbuf = malloc(MAXLOGNAME); 772 if (nbuf == NULL) 773 err(1, "malloc()"); 774 do { 775 (void)printf("%s", prompt); 776 for (p = nbuf; (ch = getchar()) != '\n'; ) { 777 if (ch == EOF) { 778 badlogin(username); 779 bail(NO_SLEEP_EXIT, 0); 780 } 781 if (p < nbuf + MAXLOGNAME - 1) 782 *p++ = ch; 783 } 784 } while (p == nbuf); 785 786 *p = '\0'; 787 if (nbuf[0] == '-') { 788 pam_silent = 0; 789 memmove(nbuf, nbuf + 1, strlen(nbuf)); 790 } else { 791 pam_silent = PAM_SILENT; 792 } 793 return nbuf; 794} 795 796/* 797 * SIGINT handler for motd(). 798 */ 799static volatile int motdinterrupt; 800static void 801sigint(int signo __unused) 802{ 803 motdinterrupt = 1; 804} 805 806/* 807 * Display the contents of a file (such as /etc/motd). 808 */ 809static int 810motd(const char *motdfile) 811{ 812 sig_t oldint; 813 FILE *f; 814 int ch; 815 816 if ((f = fopen(motdfile, "r")) == NULL) 817 return (-1); 818 motdinterrupt = 0; 819 oldint = signal(SIGINT, sigint); 820 while ((ch = fgetc(f)) != EOF && !motdinterrupt) 821 putchar(ch); 822 signal(SIGINT, oldint); 823 if (ch != EOF || ferror(f)) { 824 fclose(f); 825 return (-1); 826 } 827 fclose(f); 828 return (0); 829} 830 831/* 832 * SIGALRM handler, to enforce login prompt timeout. 833 * 834 * XXX This can potentially confuse the hell out of PAM. We should 835 * XXX instead implement a conversation function that returns 836 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal 837 * XXX handler just set a flag. 838 */ 839static void 840timedout(int signo __unused) 841{ 842 843 longjmp(timeout_buf, signo); 844} 845 846static void 847badlogin(char *name) 848{ 849 850 if (failures == 0) 851 return; 852 if (hflag) { 853 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 854 failures, failures > 1 ? "S" : "", hostname); 855 syslog(LOG_AUTHPRIV|LOG_NOTICE, 856 "%d LOGIN FAILURE%s FROM %s, %s", 857 failures, failures > 1 ? "S" : "", hostname, name); 858 } else { 859 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 860 failures, failures > 1 ? "S" : "", tty); 861 syslog(LOG_AUTHPRIV|LOG_NOTICE, 862 "%d LOGIN FAILURE%s ON %s, %s", 863 failures, failures > 1 ? "S" : "", tty, name); 864 } 865 failures = 0; 866} 867 868const char * 869stypeof(char *ttyid) 870{ 871 struct ttyent *t; 872 873 if (ttyid != NULL && *ttyid != '\0') { 874 t = getttynam(ttyid); 875 if (t != NULL && t->ty_type != NULL) 876 return (t->ty_type); 877 } 878 return (NULL); 879} 880 881static void 882refused(const char *msg, const char *rtype, int lout) 883{ 884 885 if (msg != NULL) 886 printf("%s.\n", msg); 887 if (hflag) 888 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 889 pwd->pw_name, rtype, hostname, tty); 890 else 891 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 892 pwd->pw_name, rtype, tty); 893 if (lout) 894 bail(SLEEP_EXIT, 1); 895} 896 897/* 898 * Log a PAM error 899 */ 900static void 901pam_syslog(const char *msg) 902{ 903 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err)); 904} 905 906/* 907 * Shut down PAM 908 */ 909static void 910pam_cleanup() 911{ 912 913 if (pamh != NULL) { 914 if (pam_session_established) { 915 pam_err = pam_close_session(pamh, 0); 916 if (pam_err != PAM_SUCCESS) 917 pam_syslog("pam_close_session()"); 918 } 919 pam_session_established = 0; 920 if (pam_cred_established) { 921 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED); 922 if (pam_err != PAM_SUCCESS) 923 pam_syslog("pam_setcred()"); 924 } 925 pam_cred_established = 0; 926 pam_end(pamh, pam_err); 927 pamh = NULL; 928 } 929} 930 931/* 932 * Exit, optionally after sleeping a few seconds 933 */ 934void 935bail(int sec, int eval) 936{ 937 938 pam_cleanup(); 939 (void)sleep(sec); 940 exit(eval); 941} 942