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auth.c revision 1.13 
      1 /*	$NetBSD: auth.c,v 1.13 2003/07/14 08:36:27 itojun Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)auth.c	8.3 (Berkeley) 5/30/95"
     40 #else
     41 __RCSID("$NetBSD: auth.c,v 1.13 2003/07/14 08:36:27 itojun Exp $");
     42 #endif
     43 #endif /* not lint */
     44 
     45 /*
     46  * Copyright (C) 1990 by the Massachusetts Institute of Technology
     47  *
     48  * Export of this software from the United States of America is assumed
     49  * to require a specific license from the United States Government.
     50  * It is the responsibility of any person or organization contemplating
     51  * export to obtain such a license before exporting.
     52  *
     53  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
     54  * distribute this software and its documentation for any purpose and
     55  * without fee is hereby granted, provided that the above copyright
     56  * notice appear in all copies and that both that copyright notice and
     57  * this permission notice appear in supporting documentation, and that
     58  * the name of M.I.T. not be used in advertising or publicity pertaining
     59  * to distribution of the software without specific, written prior
     60  * permission.  M.I.T. makes no representations about the suitability of
     61  * this software for any purpose.  It is provided "as is" without express
     62  * or implied warranty.
     63  */
     64 
     65 
     66 #ifdef AUTHENTICATION
     67 #include <stdio.h>
     68 #include <sys/types.h>
     69 #include <signal.h>
     70 #define	AUTH_NAMES
     71 #include <arpa/telnet.h>
     72 #include <stdlib.h>
     73 #include <unistd.h>
     74 #ifdef	NO_STRING_H
     75 #include <strings.h>
     76 #else
     77 #include <string.h>
     78 #endif
     79 
     80 #include "encrypt.h"
     81 #include "auth.h"
     82 #include "misc-proto.h"
     83 #include "auth-proto.h"
     84 
     85 #define	typemask(x)		(1<<((x)-1))
     86 
     87 #ifdef	KRB4_ENCPWD
     88 extern krb4encpwd_init();
     89 extern krb4encpwd_send();
     90 extern krb4encpwd_is();
     91 extern krb4encpwd_reply();
     92 extern krb4encpwd_status();
     93 extern krb4encpwd_printsub();
     94 #endif
     95 
     96 #ifdef	RSA_ENCPWD
     97 extern rsaencpwd_init();
     98 extern rsaencpwd_send();
     99 extern rsaencpwd_is();
    100 extern rsaencpwd_reply();
    101 extern rsaencpwd_status();
    102 extern rsaencpwd_printsub();
    103 #endif
    104 
    105 int auth_debug_mode = 0;
    106 static 	const char	*Name = "Noname";
    107 static	int	Server = 0;
    108 static	Authenticator	*authenticated = 0;
    109 static	int	authenticating = 0;
    110 static	int	validuser = 0;
    111 static	unsigned char	_auth_send_data[256];
    112 static	unsigned char	*auth_send_data;
    113 static	int	auth_send_cnt = 0;
    114 
    115 static void auth_intr P((int));
    116 
    117 /*
    118  * Authentication types supported.  Plese note that these are stored
    119  * in priority order, i.e. try the first one first.
    120  */
    121 Authenticator authenticators[] = {
    122 #ifdef	SPX
    123 	{ AUTHTYPE_SPX, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
    124 				spx_init,
    125 				spx_send,
    126 				spx_is,
    127 				spx_reply,
    128 				spx_status,
    129 				spx_printsub },
    130 	{ AUTHTYPE_SPX, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    131 				spx_init,
    132 				spx_send,
    133 				spx_is,
    134 				spx_reply,
    135 				spx_status,
    136 				spx_printsub },
    137 #endif
    138 #ifdef	KRB5
    139 # ifdef	ENCRYPTION
    140 	{ AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
    141 				kerberos5_init,
    142 				kerberos5_send,
    143 				kerberos5_is,
    144 				kerberos5_reply,
    145 				kerberos5_status,
    146 				kerberos5_printsub },
    147 # endif	/* ENCRYPTION */
    148 	{ AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    149 				kerberos5_init,
    150 				kerberos5_send,
    151 				kerberos5_is,
    152 				kerberos5_reply,
    153 				kerberos5_status,
    154 				kerberos5_printsub },
    155 #endif
    156 #ifdef	KRB4
    157 # ifdef	ENCRYPTION
    158 	{ AUTHTYPE_KERBEROS_V4, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
    159 				kerberos4_init,
    160 				kerberos4_send,
    161 				kerberos4_is,
    162 				kerberos4_reply,
    163 				kerberos4_status,
    164 				kerberos4_printsub },
    165 # endif	/* ENCRYPTION */
    166 	{ AUTHTYPE_KERBEROS_V4, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    167 				kerberos4_init,
    168 				kerberos4_send,
    169 				kerberos4_is,
    170 				kerberos4_reply,
    171 				kerberos4_status,
    172 				kerberos4_printsub },
    173 #endif
    174 #ifdef	KRB4_ENCPWD
    175 	{ AUTHTYPE_KRB4_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
    176 				krb4encpwd_init,
    177 				krb4encpwd_send,
    178 				krb4encpwd_is,
    179 				krb4encpwd_reply,
    180 				krb4encpwd_status,
    181 				krb4encpwd_printsub },
    182 #endif
    183 #ifdef	RSA_ENCPWD
    184 	{ AUTHTYPE_RSA_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    185 				rsaencpwd_init,
    186 				rsaencpwd_send,
    187 				rsaencpwd_is,
    188 				rsaencpwd_reply,
    189 				rsaencpwd_status,
    190 				rsaencpwd_printsub },
    191 #endif
    192 	{ 0, },
    193 };
    194 
    195 static Authenticator NoAuth = { 0 };
    196 
    197 static int	i_support = 0;
    198 static int	i_wont_support = 0;
    199 
    200 	Authenticator *
    201 findauthenticator(type, way)
    202 	int type;
    203 	int way;
    204 {
    205 	Authenticator *ap = authenticators;
    206 
    207 	while (ap->type && (ap->type != type || ap->way != way))
    208 		++ap;
    209 	return(ap->type ? ap : 0);
    210 }
    211 
    212 	void
    213 auth_init(name, server)
    214 	const char *name;
    215 	int server;
    216 {
    217 	Authenticator *ap = authenticators;
    218 
    219 	Server = server;
    220 	Name = name;
    221 
    222 	i_support = 0;
    223 	authenticated = 0;
    224 	authenticating = 0;
    225 	while (ap->type) {
    226 		if (!ap->init || (*ap->init)(ap, server)) {
    227 			i_support |= typemask(ap->type);
    228 			if (auth_debug_mode)
    229 				printf(">>>%s: I support auth type %d %d\r\n",
    230 					Name,
    231 					ap->type, ap->way);
    232 		}
    233 		else if (auth_debug_mode)
    234 			printf(">>>%s: Init failed: auth type %d %d\r\n",
    235 				Name, ap->type, ap->way);
    236 		++ap;
    237 	}
    238 }
    239 
    240 	void
    241 auth_disable_name(name)
    242 	char *name;
    243 {
    244 	int x;
    245 	for (x = 0; x < AUTHTYPE_CNT; ++x) {
    246 		if (!strcasecmp(name, AUTHTYPE_NAME(x))) {
    247 			i_wont_support |= typemask(x);
    248 			break;
    249 		}
    250 	}
    251 }
    252 
    253 	int
    254 getauthmask(type, maskp)
    255 	char *type;
    256 	int *maskp;
    257 {
    258 	register int x;
    259 
    260 	if (!strcasecmp(type, AUTHTYPE_NAME(0))) {
    261 		*maskp = -1;
    262 		return(1);
    263 	}
    264 
    265 	for (x = 1; x < AUTHTYPE_CNT; ++x) {
    266 		if (!strcasecmp(type, AUTHTYPE_NAME(x))) {
    267 			*maskp = typemask(x);
    268 			return(1);
    269 		}
    270 	}
    271 	return(0);
    272 }
    273 
    274 	int
    275 auth_enable(type)
    276 	char *type;
    277 {
    278 	return(auth_onoff(type, 1));
    279 }
    280 
    281 	int
    282 auth_disable(type)
    283 	char *type;
    284 {
    285 	return(auth_onoff(type, 0));
    286 }
    287 
    288 	int
    289 auth_onoff(type, on)
    290 	char *type;
    291 	int on;
    292 {
    293 	int i, mask = -1;
    294 	Authenticator *ap;
    295 
    296 	if (!strcasecmp(type, "?") || !strcasecmp(type, "help")) {
    297 		printf("auth %s 'type'\n", on ? "enable" : "disable");
    298 		printf("Where 'type' is one of:\n");
    299 		printf("\t%s\n", AUTHTYPE_NAME(0));
    300 		mask = 0;
    301 		for (ap = authenticators; ap->type; ap++) {
    302 			if ((mask & (i = typemask(ap->type))) != 0)
    303 				continue;
    304 			mask |= i;
    305 			printf("\t%s\n", AUTHTYPE_NAME(ap->type));
    306 		}
    307 		return(0);
    308 	}
    309 
    310 	if (!getauthmask(type, &mask)) {
    311 		printf("%s: invalid authentication type\n", type);
    312 		return(0);
    313 	}
    314 	if (on)
    315 		i_wont_support &= ~mask;
    316 	else
    317 		i_wont_support |= mask;
    318 	return(1);
    319 }
    320 
    321 	int
    322 auth_togdebug(on)
    323 	int on;
    324 {
    325 	if (on < 0)
    326 		auth_debug_mode ^= 1;
    327 	else
    328 		auth_debug_mode = on;
    329 	printf("auth debugging %s\n", auth_debug_mode ? "enabled" : "disabled");
    330 	return(1);
    331 }
    332 
    333 	int
    334 auth_status(s)
    335 	char *s;
    336 {
    337 	Authenticator *ap;
    338 	int i, mask;
    339 
    340 	if (i_wont_support == -1)
    341 		printf("Authentication disabled\n");
    342 	else
    343 		printf("Authentication enabled\n");
    344 
    345 	mask = 0;
    346 	for (ap = authenticators; ap->type; ap++) {
    347 		if ((mask & (i = typemask(ap->type))) != 0)
    348 			continue;
    349 		mask |= i;
    350 		printf("%s: %s\n", AUTHTYPE_NAME(ap->type),
    351 			(i_wont_support & typemask(ap->type)) ?
    352 					"disabled" : "enabled");
    353 	}
    354 	return(1);
    355 }
    356 
    357 /*
    358  * This routine is called by the server to start authentication
    359  * negotiation.
    360  */
    361 	void
    362 auth_request()
    363 {
    364 	static unsigned char str_request[64] = { IAC, SB,
    365 						 TELOPT_AUTHENTICATION,
    366 						 TELQUAL_SEND, };
    367 	Authenticator *ap = authenticators;
    368 	unsigned char *e = str_request + 4;
    369 
    370 	if (!authenticating) {
    371 		authenticating = 1;
    372 		while (ap->type) {
    373 			if (i_support & ~i_wont_support & typemask(ap->type)) {
    374 				if (auth_debug_mode) {
    375 					printf(">>>%s: Sending type %d %d\r\n",
    376 						Name, ap->type, ap->way);
    377 				}
    378 				*e++ = ap->type;
    379 				*e++ = ap->way;
    380 			}
    381 			++ap;
    382 		}
    383 		*e++ = IAC;
    384 		*e++ = SE;
    385 		telnet_net_write(str_request, e - str_request);
    386 		printsub('>', &str_request[2], e - str_request - 2);
    387 	}
    388 }
    389 
    390 /*
    391  * This is called when an AUTH SEND is received.
    392  * It should never arrive on the server side (as only the server can
    393  * send an AUTH SEND).
    394  * You should probably respond to it if you can...
    395  *
    396  * If you want to respond to the types out of order (i.e. even
    397  * if he sends  LOGIN KERBEROS and you support both, you respond
    398  * with KERBEROS instead of LOGIN (which is against what the
    399  * protocol says)) you will have to hack this code...
    400  */
    401 	void
    402 auth_send(data, cnt)
    403 	unsigned char *data;
    404 	int cnt;
    405 {
    406 	Authenticator *ap;
    407 	static unsigned char str_none[] = { IAC, SB, TELOPT_AUTHENTICATION,
    408 					    TELQUAL_IS, AUTHTYPE_NULL, 0,
    409 					    IAC, SE };
    410 	if (Server) {
    411 		if (auth_debug_mode) {
    412 			printf(">>>%s: auth_send called!\r\n", Name);
    413 		}
    414 		return;
    415 	}
    416 
    417 	if (auth_debug_mode) {
    418 		printf(">>>%s: auth_send got:", Name);
    419 		printd(data, cnt); printf("\r\n");
    420 	}
    421 
    422 	/*
    423 	 * Save the data, if it is new, so that we can continue looking
    424 	 * at it if the authorization we try doesn't work
    425 	 */
    426 	if (data < _auth_send_data ||
    427 	    data > _auth_send_data + sizeof(_auth_send_data)) {
    428 		auth_send_cnt = cnt > sizeof(_auth_send_data)
    429 					? sizeof(_auth_send_data)
    430 					: cnt;
    431 		memmove((void *)_auth_send_data, (void *)data, auth_send_cnt);
    432 		auth_send_data = _auth_send_data;
    433 	} else {
    434 		/*
    435 		 * This is probably a no-op, but we just make sure
    436 		 */
    437 		auth_send_data = data;
    438 		auth_send_cnt = cnt;
    439 	}
    440 	while ((auth_send_cnt -= 2) >= 0) {
    441 		if (auth_debug_mode)
    442 			printf(">>>%s: He supports %d\r\n",
    443 				Name, *auth_send_data);
    444 		if ((i_support & ~i_wont_support) & typemask(*auth_send_data)) {
    445 			ap = findauthenticator(auth_send_data[0],
    446 					       auth_send_data[1]);
    447 			if (ap && ap->send) {
    448 				if (auth_debug_mode)
    449 					printf(">>>%s: Trying %d %d\r\n",
    450 						Name, auth_send_data[0],
    451 							auth_send_data[1]);
    452 				if ((*ap->send)(ap)) {
    453 					/*
    454 					 * Okay, we found one we like
    455 					 * and did it.
    456 					 * we can go home now.
    457 					 */
    458 					if (auth_debug_mode)
    459 						printf(">>>%s: Using type %d\r\n",
    460 							Name, *auth_send_data);
    461 					auth_send_data += 2;
    462 					return;
    463 				}
    464 			}
    465 			/* else
    466 			 *	just continue on and look for the
    467 			 *	next one if we didn't do anything.
    468 			 */
    469 		}
    470 		auth_send_data += 2;
    471 	}
    472 	telnet_net_write(str_none, sizeof(str_none));
    473 	printsub('>', &str_none[2], sizeof(str_none) - 2);
    474 	if (auth_debug_mode)
    475 		printf(">>>%s: Sent failure message\r\n", Name);
    476 	auth_finished(0, AUTH_REJECT);
    477 #ifdef KANNAN
    478 	/*
    479 	 *  We requested strong authentication, however no mechanisms worked.
    480 	 *  Therefore, exit on client end.
    481 	 */
    482 	printf("Unable to securely authenticate user ... exit\n");
    483 	exit(0);
    484 #endif /* KANNAN */
    485 }
    486 
    487 	void
    488 auth_send_retry()
    489 {
    490 	/*
    491 	 * if auth_send_cnt <= 0 then auth_send will end up rejecting
    492 	 * the authentication and informing the other side of this.
    493 	 */
    494 	auth_send(auth_send_data, auth_send_cnt);
    495 }
    496 
    497 	void
    498 auth_is(data, cnt)
    499 	unsigned char *data;
    500 	int cnt;
    501 {
    502 	Authenticator *ap;
    503 
    504 	if (cnt < 2)
    505 		return;
    506 
    507 	if (data[0] == AUTHTYPE_NULL) {
    508 		auth_finished(0, AUTH_REJECT);
    509 		return;
    510 	}
    511 
    512 	if ((ap = findauthenticator(data[0], data[1])) != NULL) {
    513 		if (ap->is)
    514 			(*ap->is)(ap, data+2, cnt-2);
    515 	} else if (auth_debug_mode)
    516 		printf(">>>%s: Invalid authentication in IS: %d\r\n",
    517 			Name, *data);
    518 }
    519 
    520 	void
    521 auth_reply(data, cnt)
    522 	unsigned char *data;
    523 	int cnt;
    524 {
    525 	Authenticator *ap;
    526 
    527 	if (cnt < 2)
    528 		return;
    529 
    530 	if ((ap = findauthenticator(data[0], data[1])) != NULL) {
    531 		if (ap->reply)
    532 			(*ap->reply)(ap, data+2, cnt-2);
    533 	} else if (auth_debug_mode)
    534 		printf(">>>%s: Invalid authentication in SEND: %d\r\n",
    535 			Name, *data);
    536 }
    537 
    538 	void
    539 auth_name(data, cnt)
    540 	unsigned char *data;
    541 	int cnt;
    542 {
    543 	unsigned char savename[256];
    544 
    545 	if (cnt < 1) {
    546 		if (auth_debug_mode)
    547 			printf(">>>%s: Empty name in NAME\r\n", Name);
    548 		return;
    549 	}
    550 	if (cnt > sizeof(savename) - 1) {
    551 		if (auth_debug_mode)
    552 			printf(">>>%s: Name in NAME (%d) exceeds %ld length\r\n",
    553 					Name, cnt, (long)sizeof(savename)-1);
    554 		return;
    555 	}
    556 	memmove((void *)savename, (void *)data, cnt);
    557 	savename[cnt] = '\0';	/* Null terminate */
    558 	if (auth_debug_mode)
    559 		printf(">>>%s: Got NAME [%s]\r\n", Name, savename);
    560 	auth_encrypt_user(savename);
    561 }
    562 
    563 	int
    564 auth_sendname(cp, len)
    565 	unsigned char *cp;
    566 	int len;
    567 {
    568 	static unsigned char str_request[256+6]
    569 			= { IAC, SB, TELOPT_AUTHENTICATION, TELQUAL_NAME, };
    570 	register unsigned char *e = str_request + 4;
    571 	register unsigned char *ee = &str_request[sizeof(str_request)-2];
    572 
    573 	while (--len >= 0) {
    574 		if ((*e++ = *cp++) == IAC)
    575 			*e++ = IAC;
    576 		if (e >= ee)
    577 			return(0);
    578 	}
    579 	*e++ = IAC;
    580 	*e++ = SE;
    581 	telnet_net_write(str_request, e - str_request);
    582 	printsub('>', &str_request[2], e - &str_request[2]);
    583 	return(1);
    584 }
    585 
    586 	void
    587 auth_finished(ap, result)
    588 	Authenticator *ap;
    589 	int result;
    590 {
    591 	if (!(authenticated = ap))
    592 		authenticated = &NoAuth;
    593 	validuser = result;
    594 }
    595 
    596 	/* ARGSUSED */
    597 	static void
    598 auth_intr(sig)
    599 	int sig;
    600 {
    601 	auth_finished(0, AUTH_REJECT);
    602 }
    603 
    604 	int
    605 auth_wait(name)
    606 	char *name;
    607 {
    608 	if (auth_debug_mode)
    609 		printf(">>>%s: in auth_wait.\r\n", Name);
    610 
    611 	if (Server && !authenticating)
    612 		return(0);
    613 
    614 	(void) signal(SIGALRM, auth_intr);
    615 	alarm(30);
    616 	while (!authenticated)
    617 		if (telnet_spin())
    618 			break;
    619 	alarm(0);
    620 	(void) signal(SIGALRM, SIG_DFL);
    621 
    622 	/*
    623 	 * Now check to see if the user is valid or not
    624 	 */
    625 	if (!authenticated || authenticated == &NoAuth)
    626 		return(AUTH_REJECT);
    627 
    628 	if (validuser == AUTH_VALID)
    629 		validuser = AUTH_USER;
    630 
    631 	if (authenticated->status)
    632 		validuser = (*authenticated->status)(authenticated,
    633 						     name, validuser);
    634 	return(validuser);
    635 }
    636 
    637 	void
    638 auth_debug(mode)
    639 	int mode;
    640 {
    641 	auth_debug_mode = mode;
    642 }
    643 
    644 	void
    645 auth_printsub(data, cnt, buf, buflen)
    646 	unsigned char *data, *buf;
    647 	int cnt, buflen;
    648 {
    649 	Authenticator *ap;
    650 
    651 	if ((ap = findauthenticator(data[1], data[2])) && ap->printsub)
    652 		(*ap->printsub)(data, cnt, buf, buflen);
    653 	else
    654 		auth_gen_printsub(data, cnt, buf, buflen);
    655 }
    656 
    657 	void
    658 auth_gen_printsub(data, cnt, buf, buflen)
    659 	unsigned char *data, *buf;
    660 	int cnt, buflen;
    661 {
    662 	register unsigned char *cp;
    663 	unsigned char tbuf[16];
    664 
    665 	cnt -= 3;
    666 	data += 3;
    667 	buf[buflen-1] = '\0';
    668 	buf[buflen-2] = '*';
    669 	buflen -= 2;
    670 	for (; cnt > 0; cnt--, data++) {
    671 		sprintf((char *)tbuf, " %d", *data);
    672 		for (cp = tbuf; *cp && buflen > 0; --buflen)
    673 			*buf++ = *cp++;
    674 		if (buflen <= 0)
    675 			return;
    676 	}
    677 	*buf = '\0';
    678 }
    679 #endif
    680