login.c revision 107585
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 107585 2002-12-04 15:00:10Z des $"); 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 pid_t pid; 175 176 (void)signal(SIGQUIT, SIG_IGN); 177 (void)signal(SIGINT, SIG_IGN); 178 (void)signal(SIGHUP, SIG_IGN); 179 if (setjmp(timeout_buf)) { 180 if (failures) 181 badlogin(username); 182 (void)fprintf(stderr, "Login timed out after %d seconds\n", 183 timeout); 184 bail(NO_SLEEP_EXIT, 0); 185 } 186 (void)signal(SIGALRM, timedout); 187 (void)alarm(timeout); 188 (void)setpriority(PRIO_PROCESS, 0, 0); 189 190 openlog("login", LOG_ODELAY, LOG_AUTH); 191 192 uid = getuid(); 193 euid = geteuid(); 194 egid = getegid(); 195 196 while ((ch = getopt(argc, argv, "fh:p")) != -1) 197 switch (ch) { 198 case 'f': 199 fflag = 1; 200 break; 201 case 'h': 202 if (uid != 0) 203 errx(1, "-h option: %s", strerror(EPERM)); 204 if (strlen(optarg) >= MAXHOSTNAMELEN) 205 errx(1, "-h option: %s: exceeds maximum " 206 "hostname size", optarg); 207 hflag = 1; 208 hostname = optarg; 209 break; 210 case 'p': 211 pflag = 1; 212 break; 213 case '?': 214 default: 215 if (uid == 0) 216 syslog(LOG_ERR, "invalid flag %c", ch); 217 usage(); 218 } 219 argc -= optind; 220 argv += optind; 221 222 if (argc > 0) { 223 username = strdup(*argv); 224 if (username == NULL) 225 err(1, "strdup()"); 226 ask = 0; 227 } else { 228 ask = 1; 229 } 230 231 setproctitle("-%s", getprogname()); 232 233 for (cnt = getdtablesize(); cnt > 2; cnt--) 234 (void)close(cnt); 235 236 /* 237 * Get current TTY 238 */ 239 ttyn = ttyname(STDIN_FILENO); 240 if (ttyn == NULL || *ttyn == '\0') { 241 (void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY); 242 ttyn = tname; 243 } 244 if ((tty = strrchr(ttyn, '/')) != NULL) 245 ++tty; 246 else 247 tty = ttyn; 248 249 /* 250 * Get "login-retries" & "login-backoff" from default class 251 */ 252 lc = login_getclass(NULL); 253 prompt = login_getcapstr(lc, "prompt", 254 default_prompt, default_prompt); 255 passwd_prompt = login_getcapstr(lc, "passwd_prompt", 256 default_passwd_prompt, default_passwd_prompt); 257 retries = login_getcapnum(lc, "login-retries", 258 DEFAULT_RETRIES, DEFAULT_RETRIES); 259 backoff = login_getcapnum(lc, "login-backoff", 260 DEFAULT_BACKOFF, DEFAULT_BACKOFF); 261 login_close(lc); 262 lc = NULL; 263 264 /* 265 * Try to authenticate the user until we succeed or time out. 266 */ 267 for (cnt = 0;; ask = 1) { 268 if (ask) { 269 fflag = 0; 270 if (olduser != NULL) 271 free(olduser); 272 olduser = username; 273 username = getloginname(); 274 } 275 rootlogin = 0; 276 277 /* 278 * Note if trying multiple user names; log failures for 279 * previous user name, but don't bother logging one failure 280 * for nonexistent name (mistyped username). 281 */ 282 if (failures && strcmp(olduser, username) != 0) { 283 if (failures > (pwd ? 0 : 1)) 284 badlogin(olduser); 285 } 286 287 /* 288 * Load the PAM policy and set some variables 289 */ 290 pam_err = pam_start("login", username, &pamc, &pamh); 291 if (pam_err != PAM_SUCCESS) { 292 pam_syslog("pam_start()"); 293 bail(NO_SLEEP_EXIT, 1); 294 } 295 pam_err = pam_set_item(pamh, PAM_TTY, tty); 296 if (pam_err != PAM_SUCCESS) { 297 pam_syslog("pam_set_item(PAM_TTY)"); 298 bail(NO_SLEEP_EXIT, 1); 299 } 300 pam_err = pam_set_item(pamh, PAM_RHOST, hostname); 301 if (pam_err != PAM_SUCCESS) { 302 pam_syslog("pam_set_item(PAM_RHOST)"); 303 bail(NO_SLEEP_EXIT, 1); 304 } 305 306 pwd = getpwnam(username); 307 if (pwd != NULL && pwd->pw_uid == 0) 308 rootlogin = 1; 309 310 /* 311 * If the -f option was specified and the caller is 312 * root or the caller isn't changing their uid, don't 313 * authenticate. 314 */ 315 if (pwd != NULL && fflag && 316 (uid == (uid_t)0 || uid == (uid_t)pwd->pw_uid)) { 317 /* already authenticated */ 318 rval = 0; 319 } else { 320 fflag = 0; 321 (void)setpriority(PRIO_PROCESS, 0, -4); 322 rval = auth_pam(); 323 (void)setpriority(PRIO_PROCESS, 0, 0); 324 } 325 326 if (pwd && rval == 0) 327 break; 328 329 pam_cleanup(); 330 331 (void)printf("Login incorrect\n"); 332 failures++; 333 334 /* 335 * Allow up to 'retry' (10) attempts, but start 336 * backing off after 'backoff' (3) attempts. 337 */ 338 if (++cnt > backoff) { 339 if (cnt >= retries) { 340 badlogin(username); 341 bail(SLEEP_EXIT, 1); 342 } 343 sleep((u_int)((cnt - backoff) * 5)); 344 } 345 } 346 347 /* committed to login -- turn off timeout */ 348 (void)alarm((u_int)0); 349 (void)signal(SIGHUP, SIG_DFL); 350 351 endpwent(); 352 353 /* 354 * Establish the login class. 355 */ 356 lc = login_getpwclass(pwd); 357 358 quietlog = login_getcapbool(lc, "hushlogin", 0); 359 if (!quietlog) 360 pam_silent = 0; 361 362 /* 363 * Switching needed for NFS with root access disabled. 364 * 365 * XXX: This change fails to modify the additional groups for the 366 * process, and as such, may restrict rights normally granted 367 * through those groups. 368 */ 369 (void)setegid(pwd->pw_gid); 370 (void)seteuid(rootlogin ? 0 : pwd->pw_uid); 371 if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) { 372 if (login_getcapbool(lc, "requirehome", 0)) 373 refused("Home directory not available", "HOMEDIR", 1); 374 if (chdir("/") < 0) 375 refused("Cannot find root directory", "ROOTDIR", 1); 376 if (!quietlog || *pwd->pw_dir) 377 printf("No home directory.\nLogging in with home = \"/\".\n"); 378 pwd->pw_dir = strdup("/"); 379 if (pwd->pw_dir == NULL) { 380 syslog(LOG_NOTICE, "strdup(): %m"); 381 bail(SLEEP_EXIT, 1); 382 } 383 } 384 (void)seteuid(euid); 385 (void)setegid(egid); 386 if (!quietlog) 387 quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0; 388 389 shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell); 390 if (*pwd->pw_shell == '\0') 391 pwd->pw_shell = strdup(_PATH_BSHELL); 392 if (pwd->pw_shell == NULL) { 393 syslog(LOG_NOTICE, "strdup(): %m"); 394 bail(SLEEP_EXIT, 1); 395 } 396 if (*shell == '\0') /* Not overridden */ 397 shell = pwd->pw_shell; 398 if ((shell = strdup(shell)) == NULL) { 399 syslog(LOG_NOTICE, "strdup(): %m"); 400 bail(SLEEP_EXIT, 1); 401 } 402 403 /* 404 * Set device protections, depending on what terminal the 405 * user is logged in. This feature is used on Suns to give 406 * console users better privacy. 407 */ 408 login_fbtab(tty, pwd->pw_uid, pwd->pw_gid); 409 410 /* 411 * Clear flags of the tty. None should be set, and when the 412 * user sets them otherwise, this can cause the chown to fail. 413 * Since it isn't clear that flags are useful on character 414 * devices, we just clear them. 415 * 416 * We don't log in the case of EOPNOTSUPP because dev might be 417 * on NFS, which doesn't support chflags. 418 * 419 * We don't log in the EROFS because that means that /dev is on 420 * a read only file system and we assume that the permissions there 421 * are sane. 422 */ 423 if (ttyn != tname && chflags(ttyn, 0)) 424 if (errno != EOPNOTSUPP && errno != EROFS) 425 syslog(LOG_ERR, "chflags(%s): %m", ttyn); 426 if (ttyn != tname && chown(ttyn, pwd->pw_uid, 427 (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid)) 428 if (errno != EROFS) 429 syslog(LOG_ERR, "chmod(%s): %m", ttyn); 430 431 /* 432 * Exclude cons/vt/ptys only, assume dialup otherwise 433 * TODO: Make dialup tty determination a library call 434 * for consistency (finger etc.) 435 */ 436 if (hflag && isdialuptty(tty)) 437 syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name); 438 439#ifdef LOGALL 440 /* 441 * Syslog each successful login, so we don't have to watch 442 * hundreds of wtmp or lastlogin files. 443 */ 444 if (hflag) 445 syslog(LOG_INFO, "login from %s on %s as %s", 446 hostname, tty, pwd->pw_name); 447 else 448 syslog(LOG_INFO, "login on %s as %s", 449 tty, pwd->pw_name); 450#endif 451 452 /* 453 * If fflag is on, assume caller/authenticator has logged root 454 * login. 455 */ 456 if (rootlogin && fflag == 0) { 457 if (hflag) 458 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s", 459 username, tty, hostname); 460 else 461 syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s", 462 username, tty); 463 } 464 465 /* 466 * Destroy environment unless user has requested its 467 * preservation - but preserve TERM in all cases 468 */ 469 term = getenv("TERM"); 470 if (!pflag) 471 environ = envinit; 472 if (term != NULL) 473 setenv("TERM", term, 0); 474 475 /* 476 * PAM modules might add supplementary groups during pam_setcred(). 477 */ 478 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 479 syslog(LOG_ERR, "setusercontext() failed - exiting"); 480 bail(NO_SLEEP_EXIT, 1); 481 } 482 483 pam_err = pam_setcred(pamh, pam_silent|PAM_ESTABLISH_CRED); 484 if (pam_err != PAM_SUCCESS) { 485 pam_syslog("pam_setcred()"); 486 bail(NO_SLEEP_EXIT, 1); 487 } 488 pam_cred_established = 1; 489 490 pam_err = pam_open_session(pamh, pam_silent); 491 if (pam_err != PAM_SUCCESS) { 492 pam_syslog("pam_open_session()"); 493 bail(NO_SLEEP_EXIT, 1); 494 } 495 pam_session_established = 1; 496 497 /* 498 * We must fork() before setuid() because we need to call 499 * pam_close_session() as root. 500 */ 501 pid = fork(); 502 if (pid < 0) { 503 err(1, "fork"); 504 } else if (pid != 0) { 505 /* 506 * Parent: wait for child to finish, then clean up 507 * session. 508 */ 509 setproctitle("-%s [pam]", getprogname()); 510 wait(NULL); 511 bail(NO_SLEEP_EXIT, 0); 512 } 513 514 /* 515 * NOTICE: We are now in the child process! 516 */ 517 518 /* 519 * Add any environment variables the PAM modules may have set. 520 */ 521 export_pam_environment(); 522 523 /* 524 * We're done with PAM now; our parent will deal with the rest. 525 */ 526 pam_end(pamh, 0); 527 pamh = NULL; 528 529 /* 530 * We don't need to be root anymore, so set the login name and 531 * the UID. 532 */ 533 if (setlogin(username) != 0) { 534 syslog(LOG_ERR, "setlogin(%s): %m - exiting", username); 535 bail(NO_SLEEP_EXIT, 1); 536 } 537 if (setusercontext(lc, pwd, pwd->pw_uid, 538 LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) { 539 syslog(LOG_ERR, "setusercontext() failed - exiting"); 540 exit(1); 541 } 542 543 (void)setenv("SHELL", pwd->pw_shell, 1); 544 (void)setenv("HOME", pwd->pw_dir, 1); 545 /* Overwrite "term" from login.conf(5) for any known TERM */ 546 if (term == NULL && (tp = stypeof(tty)) != NULL) 547 (void)setenv("TERM", tp, 1); 548 else 549 (void)setenv("TERM", TERM_UNKNOWN, 0); 550 (void)setenv("LOGNAME", username, 1); 551 (void)setenv("USER", username, 1); 552 (void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0); 553 554 if (!quietlog) { 555 const char *cw; 556 557 cw = login_getcapstr(lc, "copyright", NULL, NULL); 558 if (cw == NULL || motd(cw) == -1) 559 (void)printf("%s", copyright); 560 561 (void)printf("\n"); 562 563 cw = login_getcapstr(lc, "welcome", NULL, NULL); 564 if (cw != NULL && access(cw, F_OK) == 0) 565 motd(cw); 566 else 567 motd(_PATH_MOTDFILE); 568 569 if (login_getcapbool(lc, "nocheckmail", 0) == 0) { 570 char *cx; 571 572 /* $MAIL may have been set by class. */ 573 cx = getenv("MAIL"); 574 if (cx == NULL) { 575 asprintf(&cx, "%s/%s", 576 _PATH_MAILDIR, pwd->pw_name); 577 } 578 if (cx && stat(cx, &st) == 0 && st.st_size != 0) 579 (void)printf("You have %smail.\n", 580 (st.st_mtime > st.st_atime) ? "new " : ""); 581 if (getenv("MAIL") == NULL) 582 free(cx); 583 } 584 } 585 586 login_close(lc); 587 588 (void)signal(SIGALRM, SIG_DFL); 589 (void)signal(SIGQUIT, SIG_DFL); 590 (void)signal(SIGINT, SIG_DFL); 591 (void)signal(SIGTSTP, SIG_IGN); 592 593 /* 594 * Login shells have a leading '-' in front of argv[0] 595 */ 596 p = strrchr(pwd->pw_shell, '/'); 597 if (asprintf(&arg0, "-%s", p ? p + 1 : pwd->pw_shell) >= MAXPATHLEN) { 598 syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size", 599 username); 600 errx(1, "shell exceeds maximum pathname size"); 601 } else if (arg0 == NULL) { 602 err(1, "asprintf()"); 603 } 604 605 execlp(shell, arg0, (char *)0); 606 err(1, "%s", shell); 607 608 /* 609 * That's it, folks! 610 */ 611} 612 613/* 614 * Attempt to authenticate the user using PAM. Returns 0 if the user is 615 * authenticated, or 1 if not authenticated. If some sort of PAM system 616 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this 617 * function returns -1. This can be used as an indication that we should 618 * fall back to a different authentication mechanism. 619 */ 620static int 621auth_pam(void) 622{ 623 const char *tmpl_user; 624 const void *item; 625 int rval; 626 627 pam_err = pam_authenticate(pamh, pam_silent); 628 switch (pam_err) { 629 630 case PAM_SUCCESS: 631 /* 632 * With PAM we support the concept of a "template" 633 * user. The user enters a login name which is 634 * authenticated by PAM, usually via a remote service 635 * such as RADIUS or TACACS+. If authentication 636 * succeeds, a different but related "template" name 637 * is used for setting the credentials, shell, and 638 * home directory. The name the user enters need only 639 * exist on the remote authentication server, but the 640 * template name must be present in the local password 641 * database. 642 * 643 * This is supported by two various mechanisms in the 644 * individual modules. However, from the application's 645 * point of view, the template user is always passed 646 * back as a changed value of the PAM_USER item. 647 */ 648 pam_err = pam_get_item(pamh, PAM_USER, &item); 649 if (pam_err == PAM_SUCCESS) { 650 tmpl_user = (const char *)item; 651 if (strcmp(username, tmpl_user) != 0) 652 pwd = getpwnam(tmpl_user); 653 } else { 654 pam_syslog("pam_get_item(PAM_USER)"); 655 } 656 rval = 0; 657 break; 658 659 case PAM_AUTH_ERR: 660 case PAM_USER_UNKNOWN: 661 case PAM_MAXTRIES: 662 rval = 1; 663 break; 664 665 default: 666 pam_syslog("pam_authenticate()"); 667 rval = -1; 668 break; 669 } 670 671 if (rval == 0) { 672 pam_err = pam_acct_mgmt(pamh, pam_silent); 673 switch (pam_err) { 674 case PAM_SUCCESS: 675 break; 676 case PAM_NEW_AUTHTOK_REQD: 677 pam_err = pam_chauthtok(pamh, 678 pam_silent|PAM_CHANGE_EXPIRED_AUTHTOK); 679 if (pam_err != PAM_SUCCESS) { 680 pam_syslog("pam_chauthtok()"); 681 rval = 1; 682 } 683 break; 684 default: 685 pam_syslog("pam_acct_mgmt()"); 686 rval = 1; 687 break; 688 } 689 } 690 691 if (rval != 0) { 692 pam_end(pamh, pam_err); 693 pamh = NULL; 694 } 695 return (rval); 696} 697 698/* 699 * Export any environment variables PAM modules may have set 700 */ 701static void 702export_pam_environment() 703{ 704 char **pam_env; 705 char **pp; 706 707 pam_env = pam_getenvlist(pamh); 708 if (pam_env != NULL) { 709 for (pp = pam_env; *pp != NULL; pp++) { 710 (void)export(*pp); 711 free(*pp); 712 } 713 } 714} 715 716/* 717 * Perform sanity checks on an environment variable: 718 * - Make sure there is an '=' in the string. 719 * - Make sure the string doesn't run on too long. 720 * - Do not export certain variables. This list was taken from the 721 * Solaris pam_putenv(3) man page. 722 * Then export it. 723 */ 724static int 725export(const char *s) 726{ 727 static const char *noexport[] = { 728 "SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH", 729 "IFS", "PATH", NULL 730 }; 731 const char **pp; 732 size_t n; 733 734 if (strlen(s) > 1024 || strchr(s, '=') == NULL) 735 return (0); 736 if (strncmp(s, "LD_", 3) == 0) 737 return (0); 738 for (pp = noexport; *pp != NULL; pp++) { 739 n = strlen(*pp); 740 if (s[n] == '=' && strncmp(s, *pp, n) == 0) 741 return (0); 742 } 743 (void)putenv(s); 744 return (1); 745} 746 747static void 748usage() 749{ 750 751 (void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n"); 752 exit(1); 753} 754 755/* 756 * Prompt user and read login name from stdin. 757 */ 758static char * 759getloginname() 760{ 761 char *nbuf, *p; 762 int ch; 763 764 nbuf = malloc(MAXLOGNAME); 765 if (nbuf == NULL) 766 err(1, "malloc()"); 767 do { 768 (void)printf("%s", prompt); 769 for (p = nbuf; (ch = getchar()) != '\n'; ) { 770 if (ch == EOF) { 771 badlogin(username); 772 bail(NO_SLEEP_EXIT, 0); 773 } 774 if (p < nbuf + MAXLOGNAME - 1) 775 *p++ = ch; 776 } 777 } while (p == nbuf); 778 779 *p = '\0'; 780 if (nbuf[0] == '-') { 781 pam_silent = 0; 782 memmove(nbuf, nbuf + 1, strlen(nbuf)); 783 } else { 784 pam_silent = PAM_SILENT; 785 } 786 return nbuf; 787} 788 789/* 790 * SIGINT handler for motd(). 791 */ 792static volatile int motdinterrupt; 793static void 794sigint(int signo __unused) 795{ 796 motdinterrupt = 1; 797} 798 799/* 800 * Display the contents of a file (such as /etc/motd). 801 */ 802static int 803motd(const char *motdfile) 804{ 805 sig_t oldint; 806 FILE *f; 807 int ch; 808 809 if ((f = fopen(motdfile, "r")) == NULL) 810 return (-1); 811 motdinterrupt = 0; 812 oldint = signal(SIGINT, sigint); 813 while ((ch = fgetc(f)) != EOF && !motdinterrupt) 814 putchar(ch); 815 signal(SIGINT, oldint); 816 if (ch != EOF || ferror(f)) { 817 fclose(f); 818 return (-1); 819 } 820 fclose(f); 821 return (0); 822} 823 824/* 825 * SIGALRM handler, to enforce login prompt timeout. 826 * 827 * XXX This can potentially confuse the hell out of PAM. We should 828 * XXX instead implement a conversation function that returns 829 * XXX PAM_CONV_ERR when interrupted by a signal, and have the signal 830 * XXX handler just set a flag. 831 */ 832static void 833timedout(int signo __unused) 834{ 835 836 longjmp(timeout_buf, signo); 837} 838 839static void 840badlogin(char *name) 841{ 842 843 if (failures == 0) 844 return; 845 if (hflag) { 846 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s", 847 failures, failures > 1 ? "S" : "", hostname); 848 syslog(LOG_AUTHPRIV|LOG_NOTICE, 849 "%d LOGIN FAILURE%s FROM %s, %s", 850 failures, failures > 1 ? "S" : "", hostname, name); 851 } else { 852 syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s", 853 failures, failures > 1 ? "S" : "", tty); 854 syslog(LOG_AUTHPRIV|LOG_NOTICE, 855 "%d LOGIN FAILURE%s ON %s, %s", 856 failures, failures > 1 ? "S" : "", tty, name); 857 } 858 failures = 0; 859} 860 861const char * 862stypeof(char *ttyid) 863{ 864 struct ttyent *t; 865 866 if (ttyid != NULL && *ttyid != '\0') { 867 t = getttynam(ttyid); 868 if (t != NULL && t->ty_type != NULL) 869 return (t->ty_type); 870 } 871 return (NULL); 872} 873 874static void 875refused(const char *msg, const char *rtype, int lout) 876{ 877 878 if (msg != NULL) 879 printf("%s.\n", msg); 880 if (hflag) 881 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s", 882 pwd->pw_name, rtype, hostname, tty); 883 else 884 syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s", 885 pwd->pw_name, rtype, tty); 886 if (lout) 887 bail(SLEEP_EXIT, 1); 888} 889 890/* 891 * Log a PAM error 892 */ 893static void 894pam_syslog(const char *msg) 895{ 896 syslog(LOG_ERR, "%s: %s", msg, pam_strerror(pamh, pam_err)); 897} 898 899/* 900 * Shut down PAM 901 */ 902static void 903pam_cleanup() 904{ 905 906 if (pamh != NULL) { 907 if (pam_session_established) { 908 pam_err = pam_close_session(pamh, 0); 909 if (pam_err != PAM_SUCCESS) 910 pam_syslog("pam_close_session()"); 911 } 912 pam_session_established = 0; 913 if (pam_cred_established) { 914 pam_err = pam_setcred(pamh, pam_silent|PAM_DELETE_CRED); 915 if (pam_err != PAM_SUCCESS) 916 pam_syslog("pam_setcred()"); 917 } 918 pam_cred_established = 0; 919 pam_end(pamh, pam_err); 920 pamh = NULL; 921 } 922} 923 924/* 925 * Exit, optionally after sleeping a few seconds 926 */ 927void 928bail(int sec, int eval) 929{ 930 931 pam_cleanup(); 932 (void)sleep(sec); 933 exit(eval); 934} 935