/release/picobsd/tinyware/login/pico-login.c

   1/*-
   2 * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
   3 *	The Regents of the University of California.  All rights reserved.
   4 *
   5 * Redistribution and use in source and binary forms, with or without
   6 * modification, are permitted provided that the following conditions
   7 * are met:
   8 * 1. Redistributions of source code must retain the above copyright
   9 *    notice, this list of conditions and the following disclaimer.
  10 * 2. Redistributions in binary form must reproduce the above copyright
  11 *    notice, this list of conditions and the following disclaimer in the
  12 *    documentation and/or other materials provided with the distribution.
  13 * 3. All advertising materials mentioning features or use of this software
  14 *    must display the following acknowledgement:
  15 *	This product includes software developed by the University of
  16 *	California, Berkeley and its contributors.
  17 * 4. Neither the name of the University nor the names of its contributors
  18 *    may be used to endorse or promote products derived from this software
  19 *    without specific prior written permission.
  20 *
  21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31 * SUCH DAMAGE.
  32 */
  33
  34#if 0
  35static char copyright[] =
  36"@(#) Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994\n\
  37	The Regents of the University of California.  All rights reserved.\n";
  38#endif
  39
  40#ifndef lint
  41#if 0
  42static char sccsid[] = "@(#)login.c	8.4 (Berkeley) 4/2/94";
  43#endif
  44static const char rcsid[] =
  45  "$FreeBSD$";
  46#endif /* not lint */
  47
  48/*
  49 * login [ name ]
  50 * login -h hostname	(for telnetd, etc.)
  51 * login -f name	(for pre-authenticated login: datakit, xterm, etc.)
  52 */
  53
  54#include <sys/copyright.h>
  55#include <sys/param.h>
  56#include <sys/stat.h>
  57#include <sys/socket.h>
  58#include <sys/time.h>
  59#include <sys/resource.h>
  60#include <sys/file.h>
  61#include <netinet/in.h>
  62#include <arpa/inet.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 <netdb.h>
  70#include <pwd.h>
  71#include <setjmp.h>
  72#include <signal.h>
  73#include <stdio.h>
  74#include <stdlib.h>
  75#include <string.h>
  76#include <syslog.h>
  77#include <ttyent.h>
  78#include <unistd.h>
  79#include <utmpx.h>
  80
  81#ifdef USE_PAM
  82#include <security/pam_appl.h>
  83#include <security/openpam.h>
  84#include <sys/wait.h>
  85#endif /* USE_PAM */
  86
  87#include "pathnames.h"
  88
  89void	 badlogin(char *);
  90void	 checknologin(void);
  91void	 dolastlog(int);
  92void	 getloginname(void);
  93void	 motd(const char *);
  94int	 rootterm(char *);
  95void	 sigint(int);
  96void	 sleepexit(int);
  97void	 refused(char *,char *,int);
  98char	*stypeof(char *);
  99void	 timedout(int);
 100int	 login_access(char *, char *);
 101void     login_fbtab(char *, uid_t, gid_t);
 102
 103#ifdef USE_PAM
 104static int auth_pam(void);
 105static int export_pam_environment(void);
 106static int ok_to_export(const char *);
 107
 108static pam_handle_t *pamh = NULL;
 109static char **environ_pam;
 110
 111#define PAM_END { \
 112	if ((e = pam_setcred(pamh, PAM_DELETE_CRED)) != PAM_SUCCESS) \
 113		syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, e)); \
 114	if ((e = pam_close_session(pamh,0)) != PAM_SUCCESS) \
 115		syslog(LOG_ERR, "pam_close_session: %s", pam_strerror(pamh, e)); \
 116	if ((e = pam_end(pamh, e)) != PAM_SUCCESS) \
 117		syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e)); \
 118}
 119#endif
 120
 121static int auth_traditional(void);
 122static void usage(void);
 123
 124#define	TTYGRPNAME	"tty"		/* name of group to own ttys */
 125#define	DEFAULT_BACKOFF	3
 126#define	DEFAULT_RETRIES	10
 127#define	DEFAULT_PROMPT		"login: "
 128#define	DEFAULT_PASSWD_PROMPT	"Password:"
 129
 130/*
 131 * This bounds the time given to login.  Not a define so it can
 132 * be patched on machines where it's too small.
 133 */
 134u_int	timeout = 300;
 135
 136/* Buffer for signal handling of timeout */
 137jmp_buf timeout_buf;
 138
 139struct	passwd *pwd;
 140int	failures;
 141char	*term, *envinit[1], *hostname, *tty, *username;
 142const char *passwd_prompt, *prompt;
 143char    full_hostname[MAXHOSTNAMELEN];
 144
 145int
 146main(argc, argv)
 147	int argc;
 148	char *argv[];
 149{
 150	extern char **environ;
 151	struct group *gr;
 152	struct stat st;
 153	struct utmpx utmp;
 154	int rootok, retries, backoff;
 155	int ask, ch, cnt, fflag, hflag, pflag, quietlog, rootlogin, rval;
 156	int changepass;
 157	time_t now, warntime;
 158	uid_t uid, euid;
 159	gid_t egid;
 160	char *p, *ttyn;
 161	char tbuf[MAXPATHLEN + 2];
 162	char tname[sizeof(_PATH_TTY) + 10];
 163	const char *shell = NULL;
 164	login_cap_t *lc = NULL;
 165	int UT_HOSTSIZE = sizeof(utmp.ut_host);
 166	int UT_NAMESIZE = sizeof(utmp.ut_user);
 167#ifdef USE_PAM
 168	pid_t pid;
 169	int e;
 170#endif /* USE_PAM */
 171
 172	(void)signal(SIGQUIT, SIG_IGN);
 173	(void)signal(SIGINT, SIG_IGN);
 174	(void)signal(SIGHUP, SIG_IGN);
 175	if (setjmp(timeout_buf)) {
 176		if (failures)
 177			badlogin(tbuf);
 178		(void)fprintf(stderr, "Login timed out after %d seconds\n",
 179		    timeout);
 180		exit(0);
 181	}
 182	(void)signal(SIGALRM, timedout);
 183	(void)alarm(timeout);
 184	(void)setpriority(PRIO_PROCESS, 0, 0);
 185
 186	openlog("login", LOG_ODELAY, LOG_AUTH);
 187
 188	/*
 189	 * -p is used by getty to tell login not to destroy the environment
 190	 * -f is used to skip a second login authentication
 191	 * -h is used by other servers to pass the name of the remote
 192	 *    host to login so that it may be placed in utmp and wtmp
 193	 */
 194	*full_hostname = '\0';
 195	term = NULL;
 196
 197	fflag = hflag = pflag = 0;
 198	uid = getuid();
 199	euid = geteuid();
 200	egid = getegid();
 201	while ((ch = getopt(argc, argv, "fh:p")) != -1)
 202		switch (ch) {
 203		case 'f':
 204			fflag = 1;
 205			break;
 206		case 'h':
 207			if (uid)
 208				errx(1, "-h option: %s", strerror(EPERM));
 209			hflag = 1;
 210			if (strlcpy(full_hostname, optarg,
 211			    sizeof(full_hostname)) >= sizeof(full_hostname))
 212				errx(1, "-h option: %s: exceeds maximum "
 213				    "hostname size", optarg);
 214
 215			trimdomain(optarg, UT_HOSTSIZE);
 216
 217			if (strlen(optarg) > UT_HOSTSIZE) {
 218				struct addrinfo hints, *res;
 219				int ga_err;
 220				
 221				memset(&hints, 0, sizeof(hints));
 222				hints.ai_family = AF_UNSPEC;
 223				ga_err = getaddrinfo(optarg, NULL, &hints,
 224				    &res);
 225				if (ga_err == 0) {
 226					char hostbuf[MAXHOSTNAMELEN];
 227
 228					getnameinfo(res->ai_addr,
 229					    res->ai_addrlen,
 230					    hostbuf,
 231					    sizeof(hostbuf), NULL, 0,
 232					    NI_NUMERICHOST);
 233					optarg = strdup(hostbuf);
 234					if (optarg == NULL) {
 235						syslog(LOG_NOTICE,
 236						    "strdup(): %m");
 237						sleepexit(1);
 238					}
 239				} else
 240					optarg = "invalid hostname";
 241				if (res != NULL)
 242					freeaddrinfo(res);
 243			}
 244			hostname = optarg;
 245			break;
 246		case 'p':
 247			pflag = 1;
 248			break;
 249		case '?':
 250		default:
 251			if (!uid)
 252				syslog(LOG_ERR, "invalid flag %c", ch);
 253			usage();
 254		}
 255	argc -= optind;
 256	argv += optind;
 257
 258	if (*argv) {
 259		username = *argv;
 260		ask = 0;
 261	} else
 262		ask = 1;
 263
 264	for (cnt = getdtablesize(); cnt > 2; cnt--)
 265		(void)close(cnt);
 266
 267	ttyn = ttyname(STDIN_FILENO);
 268	if (ttyn == NULL || *ttyn == '\0') {
 269		(void)snprintf(tname, sizeof(tname), "%s??", _PATH_TTY);
 270		ttyn = tname;
 271	}
 272	if ((tty = strrchr(ttyn, '/')) != NULL)
 273		++tty;
 274	else
 275		tty = ttyn;
 276
 277	/*
 278	 * Get "login-retries" & "login-backoff" from default class
 279	 */
 280	lc = login_getclass(NULL);
 281	prompt = login_getcapstr(lc, "login_prompt",
 282	    DEFAULT_PROMPT, DEFAULT_PROMPT);
 283	passwd_prompt = login_getcapstr(lc, "passwd_prompt",
 284	    DEFAULT_PASSWD_PROMPT, DEFAULT_PASSWD_PROMPT);
 285	retries = login_getcapnum(lc, "login-retries", DEFAULT_RETRIES,
 286	    DEFAULT_RETRIES);
 287	backoff = login_getcapnum(lc, "login-backoff", DEFAULT_BACKOFF,
 288	    DEFAULT_BACKOFF);
 289	login_close(lc);
 290	lc = NULL;
 291
 292	for (cnt = 0;; ask = 1) {
 293		if (ask) {
 294			fflag = 0;
 295			getloginname();
 296		}
 297		rootlogin = 0;
 298		rootok = rootterm(tty); /* Default (auth may change) */
 299
 300		if (strlen(username) > UT_NAMESIZE)
 301			username[UT_NAMESIZE] = '\0';
 302
 303		/*
 304		 * Note if trying multiple user names; log failures for
 305		 * previous user name, but don't bother logging one failure
 306		 * for nonexistent name (mistyped username).
 307		 */
 308		if (failures && strcmp(tbuf, username)) {
 309			if (failures > (pwd ? 0 : 1))
 310				badlogin(tbuf);
 311		}
 312		(void)strlcpy(tbuf, username, sizeof(tbuf));
 313
 314		pwd = getpwnam(username);
 315
 316		/*
 317		 * if we have a valid account name, and it doesn't have a
 318		 * password, or the -f option was specified and the caller
 319		 * is root or the caller isn't changing their uid, don't
 320		 * authenticate.
 321		 */
 322		if (pwd != NULL) {
 323			if (pwd->pw_uid == 0)
 324				rootlogin = 1;
 325
 326			if (fflag && (uid == (uid_t)0 ||
 327			    uid == (uid_t)pwd->pw_uid)) {
 328				/* already authenticated */
 329				break;
 330			} else if (pwd->pw_passwd[0] == '\0') {
 331				if (!rootlogin || rootok) {
 332					/* pretend password okay */
 333					rval = 0;
 334					goto ttycheck;
 335				}
 336			}
 337		}
 338
 339		fflag = 0;
 340
 341		(void)setpriority(PRIO_PROCESS, 0, -4);
 342
 343#ifdef USE_PAM
 344		/*
 345		 * Try to authenticate using PAM.  If a PAM system error
 346		 * occurs, perhaps because of a botched configuration,
 347		 * then fall back to using traditional Unix authentication.
 348		 */
 349		if ((rval = auth_pam()) == -1)
 350#endif /* USE_PAM */
 351			rval = auth_traditional();
 352
 353		(void)setpriority(PRIO_PROCESS, 0, 0);
 354
 355#ifdef USE_PAM
 356		/*
 357		 * PAM authentication may have changed "pwd" to the
 358		 * entry for the template user.  Check again to see if
 359		 * this is a root login after all.
 360		 */
 361		if (pwd != NULL && pwd->pw_uid == 0)
 362			rootlogin = 1;
 363#endif /* USE_PAM */
 364
 365	ttycheck:
 366		/*
 367		 * If trying to log in as root without Kerberos,
 368		 * but with insecure terminal, refuse the login attempt.
 369		 */
 370		if (pwd && !rval) {
 371			if (rootlogin && !rootok)
 372				refused(NULL, "NOROOT", 0);
 373			else	/* valid password & authenticated */
 374				break;
 375		}
 376
 377		(void)printf("Login incorrect\n");
 378		failures++;
 379
 380		/*
 381		 * we allow up to 'retry' (10) tries,
 382		 * but after 'backoff' (3) we start backing off
 383		 */
 384		if (++cnt > backoff) {
 385			if (cnt >= retries) {
 386				badlogin(username);
 387				sleepexit(1);
 388			}
 389			sleep((u_int)((cnt - backoff) * 5));
 390		}
 391	}
 392
 393	/* committed to login -- turn off timeout */
 394	(void)alarm((u_int)0);
 395	(void)signal(SIGHUP, SIG_DFL);
 396
 397	endpwent();
 398
 399	/*
 400	 * Establish the login class.
 401	 */
 402	lc = login_getpwclass(pwd);
 403
 404	/* if user not super-user, check for disabled logins */
 405	if (!rootlogin)
 406		auth_checknologin(lc);
 407
 408	quietlog = login_getcapbool(lc, "hushlogin", 0);
 409	/*
 410	 * Switching needed for NFS with root access disabled.
 411	 *
 412	 * XXX: This change fails to modify the additional groups for the
 413	 * process, and as such, may restrict rights normally granted
 414	 * through those groups.
 415	 */
 416	(void)setegid(pwd->pw_gid);
 417	(void)seteuid(rootlogin ? 0 : pwd->pw_uid);
 418	if (!*pwd->pw_dir || chdir(pwd->pw_dir) < 0) {
 419		if (login_getcapbool(lc, "requirehome", 0))
 420			refused("Home directory not available", "HOMEDIR", 1);
 421		if (chdir("/") < 0) 
 422			refused("Cannot find root directory", "ROOTDIR", 1);
 423		if (!quietlog || *pwd->pw_dir)
 424			printf("No home directory.\nLogging in with home = \"/\".\n");
 425		pwd->pw_dir = "/";
 426	}
 427	(void)seteuid(euid);
 428	(void)setegid(egid);
 429	if (!quietlog)
 430		quietlog = access(_PATH_HUSHLOGIN, F_OK) == 0;
 431
 432	now = time(NULL);
 433
 434#define	DEFAULT_WARN  (2L * 7L * 86400L)  /* Two weeks */
 435
 436	warntime = login_getcaptime(lc, "warnexpire", DEFAULT_WARN,
 437	    DEFAULT_WARN);
 438
 439	if (pwd->pw_expire) {
 440		if (now >= pwd->pw_expire) {
 441			refused("Sorry -- your account has expired", "EXPIRED",
 442			    1);
 443		} else if (pwd->pw_expire - now < warntime && !quietlog)
 444			(void)printf("Warning: your account expires on %s",
 445			    ctime(&pwd->pw_expire));
 446	}
 447
 448	warntime = login_getcaptime(lc, "warnpassword", DEFAULT_WARN,
 449	    DEFAULT_WARN);
 450
 451	changepass = 0;
 452	if (pwd->pw_change) {
 453		if (now >= pwd->pw_change) {
 454			(void)printf("Sorry -- your password has expired.\n");
 455			changepass = 1;
 456			syslog(LOG_INFO, "%s Password expired - forcing change",
 457			    pwd->pw_name);
 458		} else if (pwd->pw_change - now < warntime && !quietlog)
 459			(void)printf("Warning: your password expires on %s",
 460			    ctime(&pwd->pw_change));
 461	}
 462
 463	if (lc != NULL) {
 464		if (hostname) {
 465			struct addrinfo hints, *res;
 466			int ga_err;
 467
 468			memset(&hints, 0, sizeof(hints));
 469			hints.ai_family = AF_UNSPEC;
 470			ga_err = getaddrinfo(full_hostname, NULL, &hints,
 471					     &res);
 472			if (ga_err == 0) {
 473				char hostbuf[MAXHOSTNAMELEN];
 474
 475				getnameinfo(res->ai_addr, res->ai_addrlen,
 476				    hostbuf, sizeof(hostbuf), NULL, 0,
 477				    NI_NUMERICHOST);
 478				if ((optarg = strdup(hostbuf)) == NULL) {
 479					syslog(LOG_NOTICE, "strdup(): %m");
 480					sleepexit(1);
 481				}
 482			} else
 483				optarg = NULL;
 484			if (res != NULL)
 485				freeaddrinfo(res);
 486			if (!auth_hostok(lc, full_hostname, optarg))
 487				refused("Permission denied", "HOST", 1);
 488		}
 489
 490		if (!auth_ttyok(lc, tty))
 491			refused("Permission denied", "TTY", 1);
 492
 493		if (!auth_timeok(lc, time(NULL)))
 494			refused("Logins not available right now", "TIME", 1);
 495	}
 496        shell = login_getcapstr(lc, "shell", pwd->pw_shell, pwd->pw_shell);
 497	if (*pwd->pw_shell == '\0')
 498		pwd->pw_shell = _PATH_BSHELL;
 499	if (*shell == '\0')   /* Not overridden */
 500		shell = pwd->pw_shell;
 501	if ((shell = strdup(shell)) == NULL) {
 502		syslog(LOG_NOTICE, "strdup(): %m");
 503		sleepexit(1);
 504	}
 505
 506#ifdef LOGIN_ACCESS
 507	if (login_access(pwd->pw_name, hostname ? full_hostname : tty) == 0)
 508		refused("Permission denied", "ACCESS", 1);
 509#endif /* LOGIN_ACCESS */
 510
 511#if 1
 512	ulog_login(tty, username, hostname);
 513#else
 514	/* Nothing else left to fail -- really log in. */
 515	memset((void *)&utmp, 0, sizeof(utmp));
 516	(void)gettimeofday(&utmp.ut_tv, NULL);
 517	(void)strncpy(utmp.ut_user, username, sizeof(utmp.ut_user));
 518	if (hostname)
 519		(void)strncpy(utmp.ut_host, hostname, sizeof(utmp.ut_host));
 520	(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
 521	login(&utmp);
 522#endif
 523
 524	dolastlog(quietlog);
 525
 526	/*
 527	 * Set device protections, depending on what terminal the
 528	 * user is logged in. This feature is used on Suns to give
 529	 * console users better privacy.
 530	 */
 531	login_fbtab(tty, pwd->pw_uid, pwd->pw_gid);
 532
 533	/*
 534	 * Clear flags of the tty.  None should be set, and when the
 535	 * user sets them otherwise, this can cause the chown to fail.
 536	 * Since it isn't clear that flags are useful on character
 537	 * devices, we just clear them.
 538	 */
 539	if (chflags(ttyn, 0) && errno != EOPNOTSUPP)
 540		syslog(LOG_ERR, "chflags(%s): %m", ttyn);
 541	if (chown(ttyn, pwd->pw_uid,
 542	    (gr = getgrnam(TTYGRPNAME)) ? gr->gr_gid : pwd->pw_gid))
 543		syslog(LOG_ERR, "chown(%s): %m", ttyn);
 544
 545
 546	/*
 547	 * Preserve TERM if it happens to be already set.
 548	 */
 549	if ((term = getenv("TERM")) != NULL) {
 550		if ((term = strdup(term)) == NULL) {
 551			syslog(LOG_NOTICE,
 552			    "strdup(): %m");
 553			sleepexit(1);
 554		}
 555	}
 556
 557	/*
 558	 * Exclude cons/vt/ptys only, assume dialup otherwise
 559	 * TODO: Make dialup tty determination a library call
 560	 * for consistency (finger etc.)
 561	 */
 562	if (hostname==NULL && isdialuptty(tty))
 563		syslog(LOG_INFO, "DIALUP %s, %s", tty, pwd->pw_name);
 564
 565#ifdef LOGALL
 566	/*
 567	 * Syslog each successful login, so we don't have to watch hundreds
 568	 * of wtmp or lastlogin files.
 569	 */
 570	if (hostname)
 571		syslog(LOG_INFO, "login from %s on %s as %s",
 572		       full_hostname, tty, pwd->pw_name);
 573	else
 574		syslog(LOG_INFO, "login on %s as %s",
 575		       tty, pwd->pw_name);
 576#endif
 577
 578	/*
 579	 * If fflag is on, assume caller/authenticator has logged root login.
 580	 */
 581	if (rootlogin && fflag == 0)
 582	{
 583		if (hostname)
 584			syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s FROM %s",
 585			    username, tty, full_hostname);
 586		else
 587			syslog(LOG_NOTICE, "ROOT LOGIN (%s) ON %s",
 588			    username, tty);
 589	}
 590
 591	/*
 592	 * Destroy environment unless user has requested its preservation.
 593	 * We need to do this before setusercontext() because that may
 594	 * set or reset some environment variables.
 595	 */
 596	if (!pflag)
 597		environ = envinit;
 598
 599	/*
 600	 * PAM modules might add supplementary groups during pam_setcred().
 601	 */
 602	if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
 603                syslog(LOG_ERR, "setusercontext() failed - exiting");
 604		exit(1);
 605	}
 606
 607#ifdef USE_PAM
 608	if (pamh) {
 609		if ((e = pam_open_session(pamh, 0)) != PAM_SUCCESS) {
 610			syslog(LOG_ERR, "pam_open_session: %s",
 611			    pam_strerror(pamh, e));
 612		} else if ((e = pam_setcred(pamh, PAM_ESTABLISH_CRED))
 613		    != PAM_SUCCESS) {
 614			syslog(LOG_ERR, "pam_setcred: %s",
 615			    pam_strerror(pamh, e));
 616		}
 617
 618	        /*
 619	         * Add any environmental variables that the
 620	         * PAM modules may have set.
 621		 * Call *after* opening session!
 622		 */
 623		if (pamh) {
 624		  environ_pam = pam_getenvlist(pamh);
 625		  if (environ_pam)
 626			export_pam_environment();
 627		}
 628
 629		/*
 630		 * We must fork() before setuid() because we need to call
 631		 * pam_close_session() as root.
 632		 */
 633		pid = fork();
 634		if (pid < 0) {
 635			err(1, "fork");
 636			PAM_END;
 637			exit(0);
 638		} else if (pid) {
 639			/* parent - wait for child to finish, then cleanup
 640			   session */
 641			wait(NULL);
 642			PAM_END;
 643			exit(0);
 644		} else {
 645			if ((e = pam_end(pamh, 0)) != PAM_SUCCESS)
 646				syslog(LOG_ERR, "pam_end: %s",
 647				    pam_strerror(pamh, e));
 648		}
 649	}
 650#endif /* USE_PAM */
 651
 652	/*
 653	 * We don't need to be root anymore, so
 654	 * set the user and session context
 655	 */
 656	if (setlogin(username) != 0) {
 657                syslog(LOG_ERR, "setlogin(%s): %m - exiting", username);
 658		exit(1);
 659	}
 660	if (setusercontext(lc, pwd, pwd->pw_uid,
 661	    LOGIN_SETALL & ~(LOGIN_SETLOGIN|LOGIN_SETGROUP)) != 0) {
 662                syslog(LOG_ERR, "setusercontext() failed - exiting");
 663		exit(1);
 664	}
 665
 666	(void)setenv("SHELL", pwd->pw_shell, 1);
 667	(void)setenv("HOME", pwd->pw_dir, 1);
 668	if (term != NULL && *term != '\0')
 669		(void)setenv("TERM", term, 1);		/* Preset overrides */
 670	else {
 671		(void)setenv("TERM", stypeof(tty), 0);	/* Fallback doesn't */
 672	}
 673	(void)setenv("LOGNAME", username, 1);
 674	(void)setenv("USER", username, 1);
 675	(void)setenv("PATH", rootlogin ? _PATH_STDPATH : _PATH_DEFPATH, 0);
 676
 677	if (!quietlog) {
 678		const char *cw;
 679
 680		cw = login_getcapstr(lc, "copyright", NULL, NULL);
 681		if (cw != NULL && access(cw, F_OK) == 0)
 682			motd(cw);
 683		else
 684		    (void)printf("%s\n\t%s %s\n",
 685	"Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994",
 686	"The Regents of the University of California. ",
 687	"All rights reserved.");
 688
 689		(void)printf("\n");
 690
 691		cw = login_getcapstr(lc, "welcome", NULL, NULL);
 692		if (cw == NULL || access(cw, F_OK) != 0)
 693			cw = _PATH_MOTDFILE;
 694		motd(cw);
 695
 696		cw = getenv("MAIL");	/* $MAIL may have been set by class */
 697		if (cw != NULL)
 698			strlcpy(tbuf, cw, sizeof(tbuf));
 699		else
 700			snprintf(tbuf, sizeof(tbuf), "%s/%s", _PATH_MAILDIR,
 701			    pwd->pw_name);
 702		if (stat(tbuf, &st) == 0 && st.st_size != 0)
 703			(void)printf("You have %smail.\n",
 704			    (st.st_mtime > st.st_atime) ? "new " : "");
 705	}
 706
 707	login_close(lc);
 708
 709	(void)signal(SIGALRM, SIG_DFL);
 710	(void)signal(SIGQUIT, SIG_DFL);
 711	(void)signal(SIGINT, SIG_DFL);
 712	(void)signal(SIGTSTP, SIG_IGN);
 713
 714	/*
 715	 * Login shells have a leading '-' in front of argv[0]
 716	 */
 717	if (snprintf(tbuf, sizeof(tbuf), "-%s",
 718	    (p = strrchr(pwd->pw_shell, '/')) ? p + 1 : pwd->pw_shell) >=
 719	    sizeof(tbuf)) {
 720		syslog(LOG_ERR, "user: %s: shell exceeds maximum pathname size",
 721		    username);
 722		errx(1, "shell exceeds maximum pathname size");
 723	}
 724
 725	execlp(shell, tbuf, (char *)0);
 726	err(1, "%s", shell);
 727}
 728
 729static int
 730auth_traditional()
 731{
 732	int rval;
 733	char *p;
 734	char *ep;
 735	char *salt;
 736
 737	rval = 1;
 738	salt = pwd != NULL ? pwd->pw_passwd : "xx";
 739
 740	p = getpass(passwd_prompt);
 741	ep = crypt(p, salt);
 742
 743	if (pwd) {
 744		if (!p[0] && pwd->pw_passwd[0])
 745			ep = ":";
 746		if (strcmp(ep, pwd->pw_passwd) == 0)
 747			rval = 0;
 748	}
 749
 750	/* clear entered password */
 751	memset(p, 0, strlen(p));
 752	return rval;
 753}
 754
 755#ifdef USE_PAM
 756/*
 757 * Attempt to authenticate the user using PAM.  Returns 0 if the user is
 758 * authenticated, or 1 if not authenticated.  If some sort of PAM system
 759 * error occurs (e.g., the "/etc/pam.conf" file is missing) then this
 760 * function returns -1.  This can be used as an indication that we should
 761 * fall back to a different authentication mechanism.
 762 */
 763static int
 764auth_pam()
 765{
 766	const char *tmpl_user;
 767	const void *item;
 768	int rval;
 769	int e;
 770	static struct pam_conv conv = { openpam_ttyconv, NULL };
 771
 772	if ((e = pam_start("login", username, &conv, &pamh)) != PAM_SUCCESS) {
 773		syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e));
 774		return -1;
 775	}
 776	if ((e = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS) {
 777		syslog(LOG_ERR, "pam_set_item(PAM_TTY): %s",
 778		    pam_strerror(pamh, e));
 779		return -1;
 780	}
 781	if (hostname != NULL &&
 782	    (e = pam_set_item(pamh, PAM_RHOST, full_hostname)) != PAM_SUCCESS) {
 783		syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
 784		    pam_strerror(pamh, e));
 785		return -1;
 786	}
 787	e = pam_authenticate(pamh, 0);
 788	switch (e) {
 789
 790	case PAM_SUCCESS:
 791		/*
 792		 * With PAM we support the concept of a "template"
 793		 * user.  The user enters a login name which is
 794		 * authenticated by PAM, usually via a remote service
 795		 * such as RADIUS or TACACS+.  If authentication
 796		 * succeeds, a different but related "template" name
 797		 * is used for setting the credentials, shell, and
 798		 * home directory.  The name the user enters need only
 799		 * exist on the remote authentication server, but the
 800		 * template name must be present in the local password
 801		 * database.
 802		 *
 803		 * This is supported by two various mechanisms in the
 804		 * individual modules.  However, from the application's
 805		 * point of view, the template user is always passed
 806		 * back as a changed value of the PAM_USER item.
 807		 */
 808		if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
 809		    PAM_SUCCESS) {
 810			tmpl_user = (const char *) item;
 811			if (strcmp(username, tmpl_user) != 0)
 812				pwd = getpwnam(tmpl_user);
 813		} else
 814			syslog(LOG_ERR, "Couldn't get PAM_USER: %s",
 815			    pam_strerror(pamh, e));
 816		rval = 0;
 817		break;
 818
 819	case PAM_AUTH_ERR:
 820	case PAM_USER_UNKNOWN:
 821	case PAM_MAXTRIES:
 822		rval = 1;
 823		break;
 824
 825	default:
 826		syslog(LOG_ERR, "pam_authenticate: %s", pam_strerror(pamh, e));
 827		rval = -1;
 828		break;
 829	}
 830
 831	if (rval == 0) {
 832		e = pam_acct_mgmt(pamh, 0);
 833		if (e == PAM_NEW_AUTHTOK_REQD) {
 834			e = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
 835			if (e != PAM_SUCCESS) {
 836				syslog(LOG_ERR, "pam_chauthtok: %s",
 837				    pam_strerror(pamh, e));
 838				rval = 1;
 839			}
 840		} else if (e != PAM_SUCCESS) {
 841			rval = 1;
 842		}
 843	}
 844
 845	if (rval != 0) {
 846		if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
 847			syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
 848		}
 849		pamh = NULL;
 850	}
 851	return rval;
 852}
 853
 854static int
 855export_pam_environment()
 856{
 857	char	**pp;
 858
 859	for (pp = environ_pam; *pp != NULL; pp++) {
 860		if (ok_to_export(*pp))
 861			(void) putenv(*pp);
 862		free(*pp);
 863	}
 864	return PAM_SUCCESS;
 865}
 866
 867/*
 868 * Sanity checks on PAM environmental variables:
 869 * - Make sure there is an '=' in the string.
 870 * - Make sure the string doesn't run on too long.
 871 * - Do not export certain variables.  This list was taken from the
 872 *   Solaris pam_putenv(3) man page.
 873 */
 874static int
 875ok_to_export(s)
 876	const char *s;
 877{
 878	static const char *noexport[] = {
 879		"SHELL", "HOME", "LOGNAME", "MAIL", "CDPATH",
 880		"IFS", "PATH", NULL
 881	};
 882	const char **pp;
 883	size_t n;
 884
 885	if (strlen(s) > 1024 || strchr(s, '=') == NULL)
 886		return 0;
 887	if (strncmp(s, "LD_", 3) == 0)
 888		return 0;
 889	for (pp = noexport; *pp != NULL; pp++) {
 890		n = strlen(*pp);
 891		if (s[n] == '=' && strncmp(s, *pp, n) == 0)
 892			return 0;
 893	}
 894	return 1;
 895}
 896#endif /* USE_PAM */
 897
 898static void
 899usage()
 900{
 901
 902	(void)fprintf(stderr, "usage: login [-fp] [-h hostname] [username]\n");
 903	exit(1);
 904}
 905
 906/*
 907 * Allow for authentication style and/or kerberos instance
 908 */
 909
 910#define	NBUFSIZ		128	// XXX was UT_NAMESIZE + 64
 911
 912void
 913getloginname()
 914{
 915	int ch;
 916	char *p;
 917	static char nbuf[NBUFSIZ];
 918
 919	for (;;) {
 920		(void)printf("%s", prompt);
 921		for (p = nbuf; (ch = getchar()) != '\n'; ) {
 922			if (ch == EOF) {
 923				badlogin(username);
 924				exit(0);
 925			}
 926			if (p < nbuf + (NBUFSIZ - 1))
 927				*p++ = ch;
 928		}
 929		if (p > nbuf) {
 930			if (nbuf[0] == '-')
 931				(void)fprintf(stderr,
 932				    "login names may not start with '-'.\n");
 933			else {
 934				*p = '\0';
 935				username = nbuf;
 936				break;
 937			}
 938		}
 939	}
 940}
 941
 942int
 943rootterm(ttyn)
 944	char *ttyn;
 945{
 946	struct ttyent *t;
 947
 948	return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
 949}
 950
 951volatile int motdinterrupt;
 952
 953void
 954sigint(signo)
 955	int signo __unused;
 956{
 957	motdinterrupt = 1;
 958}
 959
 960void
 961motd(motdfile)
 962	const char *motdfile;
 963{
 964	int fd, nchars;
 965	sig_t oldint;
 966	char tbuf[256];
 967
 968	if ((fd = open(motdfile, O_RDONLY, 0)) < 0)
 969		return;
 970	motdinterrupt = 0;
 971	oldint = signal(SIGINT, sigint);
 972	while ((nchars = read(fd, tbuf, sizeof(tbuf))) > 0 && !motdinterrupt)
 973		(void)write(fileno(stdout), tbuf, nchars);
 974	(void)signal(SIGINT, oldint);
 975	(void)close(fd);
 976}
 977
 978/* ARGSUSED */
 979void
 980timedout(signo)
 981	int signo;
 982{
 983
 984	longjmp(timeout_buf, signo);
 985}
 986
 987
 988void
 989dolastlog(quiet)
 990	int quiet;
 991{
 992#if 0	/* XXX not implemented after utmp->utmpx change */
 993	struct lastlog ll;
 994	int fd;
 995
 996	if ((fd = open(_PATH_LASTLOG, O_RDWR, 0)) >= 0) {
 997		(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
 998		if (!quiet) {
 999			if (read(fd, (char *)&ll, sizeof(ll)) == sizeof(ll) &&
1000			    ll.ll_time != 0) {
1001				(void)printf("Last login: %.*s ",
1002				    24-5, (char *)ctime(&ll.ll_time));
1003				if (*ll.ll_host != '\0')
1004					(void)printf("from %.*s\n",
1005					    (int)sizeof(ll.ll_host),
1006					    ll.ll_host);
1007				else
1008					(void)printf("on %.*s\n",
1009					    (int)sizeof(ll.ll_line),
1010					    ll.ll_line);
1011			}
1012			(void)lseek(fd, (off_t)pwd->pw_uid * sizeof(ll), L_SET);
1013		}
1014		memset((void *)&ll, 0, sizeof(ll));
1015		(void)time(&ll.ll_time);
1016		(void)strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
1017		if (hostname)
1018			(void)strncpy(ll.ll_host, hostname, sizeof(ll.ll_host));
1019		(void)write(fd, (char *)&ll, sizeof(ll));
1020		(void)close(fd);
1021	} else {
1022		syslog(LOG_ERR, "cannot open %s: %m", _PATH_LASTLOG);
1023	}
1024#endif
1025}
1026
1027void
1028badlogin(name)
1029	char *name;
1030{
1031
1032	if (failures == 0)
1033		return;
1034	if (hostname) {
1035		syslog(LOG_NOTICE, "%d LOGIN FAILURE%s FROM %s",
1036		    failures, failures > 1 ? "S" : "", full_hostname);
1037		syslog(LOG_AUTHPRIV|LOG_NOTICE,
1038		    "%d LOGIN FAILURE%s FROM %s, %s",
1039		    failures, failures > 1 ? "S" : "", full_hostname, name);
1040	} else {
1041		syslog(LOG_NOTICE, "%d LOGIN FAILURE%s ON %s",
1042		    failures, failures > 1 ? "S" : "", tty);
1043		syslog(LOG_AUTHPRIV|LOG_NOTICE,
1044		    "%d LOGIN FAILURE%s ON %s, %s",
1045		    failures, failures > 1 ? "S" : "", tty, name);
1046	}
1047	failures = 0;
1048}
1049
1050#undef	UNKNOWN
1051#define	UNKNOWN	"su"
1052
1053char *
1054stypeof(ttyid)
1055	char *ttyid;
1056{
1057	struct ttyent *t;
1058
1059	if (ttyid != NULL && *ttyid != '\0') {
1060		t = getttynam(ttyid);
1061		if (t != NULL && t->ty_type != NULL)
1062			return (t->ty_type);
1063	}
1064	return (UNKNOWN);
1065}
1066
1067void
1068refused(msg, rtype, lout)
1069	char *msg;
1070	char *rtype;
1071	int lout;
1072{
1073
1074	if (msg != NULL)
1075	    printf("%s.\n", msg);
1076	if (hostname)
1077		syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) FROM %s ON TTY %s",
1078		    pwd->pw_name, rtype, full_hostname, tty);
1079	else
1080		syslog(LOG_NOTICE, "LOGIN %s REFUSED (%s) ON TTY %s",
1081		    pwd->pw_name, rtype, tty);
1082	if (lout)
1083		sleepexit(1);
1084}
1085
1086void
1087sleepexit(eval)
1088	int eval;
1089{
1090
1091	(void)sleep(5);
1092	exit(eval);
1093}