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auth.c revision 1.21 
      1 /*	$NetBSD: auth.c,v 1.21 2012/03/21 05:33:27 matt 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. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)auth.c	8.3 (Berkeley) 5/30/95"
     36 #else
     37 __RCSID("$NetBSD: auth.c,v 1.21 2012/03/21 05:33:27 matt Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 /*
     42  * Copyright (C) 1990 by the Massachusetts Institute of Technology
     43  *
     44  * Export of this software from the United States of America is assumed
     45  * to require a specific license from the United States Government.
     46  * It is the responsibility of any person or organization contemplating
     47  * export to obtain such a license before exporting.
     48  *
     49  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
     50  * distribute this software and its documentation for any purpose and
     51  * without fee is hereby granted, provided that the above copyright
     52  * notice appear in all copies and that both that copyright notice and
     53  * this permission notice appear in supporting documentation, and that
     54  * the name of M.I.T. not be used in advertising or publicity pertaining
     55  * to distribution of the software without specific, written prior
     56  * permission.  M.I.T. makes no representations about the suitability of
     57  * this software for any purpose.  It is provided "as is" without express
     58  * or implied warranty.
     59  */
     60 
     61 
     62 #ifdef AUTHENTICATION
     63 #include <stdio.h>
     64 #include <sys/types.h>
     65 #include <signal.h>
     66 #define	AUTH_NAMES
     67 #include <arpa/telnet.h>
     68 #include <stdlib.h>
     69 #include <unistd.h>
     70 #ifdef	NO_STRING_H
     71 #include <strings.h>
     72 #else
     73 #include <string.h>
     74 #endif
     75 
     76 #include "encrypt.h"
     77 #include "auth.h"
     78 #include "misc-proto.h"
     79 #include "auth-proto.h"
     80 
     81 #define	typemask(x)		(1<<((x)-1))
     82 
     83 #ifdef	RSA_ENCPWD
     84 extern rsaencpwd_init();
     85 extern rsaencpwd_send();
     86 extern rsaencpwd_is();
     87 extern rsaencpwd_reply();
     88 extern rsaencpwd_status();
     89 extern rsaencpwd_printsub();
     90 #endif
     91 
     92 int auth_debug_mode = 0;
     93 static 	const char	*Name = "Noname";
     94 static	int	Server = 0;
     95 static	Authenticator	*authenticated = 0;
     96 static	int	authenticating = 0;
     97 static	int	validuser = 0;
     98 static	unsigned char	_auth_send_data[256];
     99 static	unsigned char	*auth_send_data;
    100 static	int	auth_send_cnt = 0;
    101 
    102 static void auth_intr(int);
    103 
    104 /*
    105  * Authentication types supported.  Plese note that these are stored
    106  * in priority order, i.e. try the first one first.
    107  */
    108 Authenticator authenticators[] = {
    109 #ifdef	SPX
    110 	{ AUTHTYPE_SPX, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
    111 				spx_init,
    112 				spx_send,
    113 				spx_is,
    114 				spx_reply,
    115 				spx_status,
    116 				spx_printsub },
    117 	{ AUTHTYPE_SPX, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    118 				spx_init,
    119 				spx_send,
    120 				spx_is,
    121 				spx_reply,
    122 				spx_status,
    123 				spx_printsub },
    124 #endif
    125 #ifdef	KRB5
    126 # ifdef	ENCRYPTION
    127 	{ AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
    128 				kerberos5_init,
    129 				kerberos5_send,
    130 				kerberos5_is,
    131 				kerberos5_reply,
    132 				kerberos5_status,
    133 				kerberos5_printsub },
    134 # endif	/* ENCRYPTION */
    135 	{ AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    136 				kerberos5_init,
    137 				kerberos5_send,
    138 				kerberos5_is,
    139 				kerberos5_reply,
    140 				kerberos5_status,
    141 				kerberos5_printsub },
    142 #endif
    143 #ifdef	RSA_ENCPWD
    144 	{ AUTHTYPE_RSA_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    145 				rsaencpwd_init,
    146 				rsaencpwd_send,
    147 				rsaencpwd_is,
    148 				rsaencpwd_reply,
    149 				rsaencpwd_status,
    150 				rsaencpwd_printsub },
    151 #endif
    152 #ifdef SRA
    153 	{ AUTHTYPE_SRA, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
    154 				sra_init,
    155 				sra_send,
    156 				sra_is,
    157 				sra_reply,
    158 				sra_status,
    159 				sra_printsub },
    160 
    161 #endif
    162 	{ 0, 0, 0, 0, 0, 0, 0, 0 },
    163 };
    164 
    165 static Authenticator NoAuth = { .type = 0 };
    166 
    167 static int	i_support = 0;
    168 static int	i_wont_support = 0;
    169 
    170 Authenticator *
    171 findauthenticator(int type, int way)
    172 {
    173 	Authenticator *ap = authenticators;
    174 
    175 	while (ap->type && (ap->type != type || ap->way != way))
    176 		++ap;
    177 	return(ap->type ? ap : 0);
    178 }
    179 
    180 void
    181 auth_init(const char *name, int server)
    182 {
    183 	Authenticator *ap = authenticators;
    184 
    185 	Server = server;
    186 	Name = name;
    187 
    188 	i_support = 0;
    189 	authenticated = 0;
    190 	authenticating = 0;
    191 	while (ap->type) {
    192 		if (!ap->init || (*ap->init)(ap, server)) {
    193 			i_support |= typemask(ap->type);
    194 			if (auth_debug_mode)
    195 				printf(">>>%s: I support auth type %d %d\r\n",
    196 					Name,
    197 					ap->type, ap->way);
    198 		}
    199 		else if (auth_debug_mode)
    200 			printf(">>>%s: Init failed: auth type %d %d\r\n",
    201 				Name, ap->type, ap->way);
    202 		++ap;
    203 	}
    204 }
    205 
    206 void
    207 auth_disable_name(char *name)
    208 {
    209 	int x;
    210 	for (x = 0; x < AUTHTYPE_CNT; ++x) {
    211 		if (AUTHTYPE_NAME(x) && !strcasecmp(name, AUTHTYPE_NAME(x))) {
    212 			i_wont_support |= typemask(x);
    213 			break;
    214 		}
    215 	}
    216 }
    217 
    218 int
    219 getauthmask(char *type, int *maskp)
    220 {
    221 	register int x;
    222 
    223 	if (AUTHTYPE_NAME(0) && !strcasecmp(type, AUTHTYPE_NAME(0))) {
    224 		*maskp = -1;
    225 		return(1);
    226 	}
    227 
    228 	for (x = 1; x < AUTHTYPE_CNT; ++x) {
    229 		if (AUTHTYPE_NAME(x) && !strcasecmp(type, AUTHTYPE_NAME(x))) {
    230 			*maskp = typemask(x);
    231 			return(1);
    232 		}
    233 	}
    234 	return(0);
    235 }
    236 
    237 int
    238 auth_enable(char *type)
    239 {
    240 	return(auth_onoff(type, 1));
    241 }
    242 
    243 int
    244 auth_disable(char *type)
    245 {
    246 	return(auth_onoff(type, 0));
    247 }
    248 
    249 int
    250 auth_onoff(char *type, int on)
    251 {
    252 	int i, mask = -1;
    253 	Authenticator *ap;
    254 
    255 	if (!strcasecmp(type, "?") || !strcasecmp(type, "help")) {
    256 		printf("auth %s 'type'\n", on ? "enable" : "disable");
    257 		printf("Where 'type' is one of:\n");
    258 		printf("\t%s\n", AUTHTYPE_NAME(0));
    259 		mask = 0;
    260 		for (ap = authenticators; ap->type; ap++) {
    261 			if ((mask & (i = typemask(ap->type))) != 0)
    262 				continue;
    263 			mask |= i;
    264 			printf("\t%s\n", AUTHTYPE_NAME(ap->type));
    265 		}
    266 		return(0);
    267 	}
    268 
    269 	if (!getauthmask(type, &mask)) {
    270 		printf("%s: invalid authentication type\n", type);
    271 		return(0);
    272 	}
    273 	if (on)
    274 		i_wont_support &= ~mask;
    275 	else
    276 		i_wont_support |= mask;
    277 	return(1);
    278 }
    279 
    280 int
    281 auth_togdebug(int on)
    282 {
    283 	if (on < 0)
    284 		auth_debug_mode ^= 1;
    285 	else
    286 		auth_debug_mode = on;
    287 	printf("auth debugging %s\n", auth_debug_mode ? "enabled" : "disabled");
    288 	return(1);
    289 }
    290 
    291 int
    292 auth_status(char *s)
    293 {
    294 	Authenticator *ap;
    295 	int i, mask;
    296 
    297 	if (i_wont_support == -1)
    298 		printf("Authentication disabled\n");
    299 	else
    300 		printf("Authentication enabled\n");
    301 
    302 	mask = 0;
    303 	for (ap = authenticators; ap->type; ap++) {
    304 		if ((mask & (i = typemask(ap->type))) != 0)
    305 			continue;
    306 		mask |= i;
    307 		printf("%s: %s\n", AUTHTYPE_NAME(ap->type),
    308 			(i_wont_support & typemask(ap->type)) ?
    309 					"disabled" : "enabled");
    310 	}
    311 	return(1);
    312 }
    313 
    314 /*
    315  * This routine is called by the server to start authentication
    316  * negotiation.
    317  */
    318 void
    319 auth_request(void)
    320 {
    321 	static unsigned char str_request[64] = { IAC, SB,
    322 						 TELOPT_AUTHENTICATION,
    323 						 TELQUAL_SEND, };
    324 	Authenticator *ap = authenticators;
    325 	unsigned char *e = str_request + 4;
    326 
    327 	if (!authenticating) {
    328 		authenticating = 1;
    329 		while (ap->type) {
    330 			if (i_support & ~i_wont_support & typemask(ap->type)) {
    331 				if (auth_debug_mode) {
    332 					printf(">>>%s: Sending type %d %d\r\n",
    333 						Name, ap->type, ap->way);
    334 				}
    335 				*e++ = ap->type;
    336 				*e++ = ap->way;
    337 			}
    338 			++ap;
    339 		}
    340 		*e++ = IAC;
    341 		*e++ = SE;
    342 		telnet_net_write(str_request, e - str_request);
    343 		printsub('>', &str_request[2], e - str_request - 2);
    344 	}
    345 }
    346 
    347 /*
    348  * This is called when an AUTH SEND is received.
    349  * It should never arrive on the server side (as only the server can
    350  * send an AUTH SEND).
    351  * You should probably respond to it if you can...
    352  *
    353  * If you want to respond to the types out of order (i.e. even
    354  * if he sends  LOGIN KERBEROS and you support both, you respond
    355  * with KERBEROS instead of LOGIN (which is against what the
    356  * protocol says)) you will have to hack this code...
    357  */
    358 void
    359 auth_send(unsigned char *data, int cnt)
    360 {
    361 	Authenticator *ap;
    362 	static unsigned char str_none[] = { IAC, SB, TELOPT_AUTHENTICATION,
    363 					    TELQUAL_IS, AUTHTYPE_NULL, 0,
    364 					    IAC, SE };
    365 	if (Server) {
    366 		if (auth_debug_mode) {
    367 			printf(">>>%s: auth_send called!\r\n", Name);
    368 		}
    369 		return;
    370 	}
    371 
    372 	if (auth_debug_mode) {
    373 		printf(">>>%s: auth_send got:", Name);
    374 		printd(data, cnt); printf("\r\n");
    375 	}
    376 
    377 	/*
    378 	 * Save the data, if it is new, so that we can continue looking
    379 	 * at it if the authorization we try doesn't work
    380 	 */
    381 	if (data < _auth_send_data ||
    382 	    data > _auth_send_data + sizeof(_auth_send_data)) {
    383 		auth_send_cnt = (size_t)cnt > sizeof(_auth_send_data)
    384 					? sizeof(_auth_send_data)
    385 					: (size_t)cnt;
    386 		memmove(_auth_send_data, data, auth_send_cnt);
    387 		auth_send_data = _auth_send_data;
    388 	} else {
    389 		/*
    390 		 * This is probably a no-op, but we just make sure
    391 		 */
    392 		auth_send_data = data;
    393 		auth_send_cnt = cnt;
    394 	}
    395 	while ((auth_send_cnt -= 2) >= 0) {
    396 		if (auth_debug_mode)
    397 			printf(">>>%s: He supports %d\r\n",
    398 				Name, *auth_send_data);
    399 		if ((i_support & ~i_wont_support) & typemask(*auth_send_data)) {
    400 			ap = findauthenticator(auth_send_data[0],
    401 					       auth_send_data[1]);
    402 			if (ap && ap->send) {
    403 				if (auth_debug_mode)
    404 					printf(">>>%s: Trying %d %d\r\n",
    405 						Name, auth_send_data[0],
    406 							auth_send_data[1]);
    407 				if ((*ap->send)(ap)) {
    408 					/*
    409 					 * Okay, we found one we like
    410 					 * and did it.
    411 					 * we can go home now.
    412 					 */
    413 					if (auth_debug_mode)
    414 						printf(">>>%s: Using type %d\r\n",
    415 							Name, *auth_send_data);
    416 					auth_send_data += 2;
    417 					return;
    418 				}
    419 			}
    420 			/* else
    421 			 *	just continue on and look for the
    422 			 *	next one if we didn't do anything.
    423 			 */
    424 		}
    425 		auth_send_data += 2;
    426 	}
    427 	telnet_net_write(str_none, sizeof(str_none));
    428 	printsub('>', &str_none[2], sizeof(str_none) - 2);
    429 	if (auth_debug_mode)
    430 		printf(">>>%s: Sent failure message\r\n", Name);
    431 	auth_finished(0, AUTH_REJECT);
    432 #ifdef KANNAN
    433 	/*
    434 	 *  We requested strong authentication, however no mechanisms worked.
    435 	 *  Therefore, exit on client end.
    436 	 */
    437 	printf("Unable to securely authenticate user ... exit\n");
    438 	exit(0);
    439 #endif /* KANNAN */
    440 }
    441 
    442 void
    443 auth_send_retry(void)
    444 {
    445 	/*
    446 	 * if auth_send_cnt <= 0 then auth_send will end up rejecting
    447 	 * the authentication and informing the other side of this.
    448 	 */
    449 	auth_send(auth_send_data, auth_send_cnt);
    450 }
    451 
    452 void
    453 auth_is(unsigned char *data, int cnt)
    454 {
    455 	Authenticator *ap;
    456 
    457 	if (cnt < 2)
    458 		return;
    459 
    460 	if (data[0] == AUTHTYPE_NULL) {
    461 		auth_finished(0, AUTH_REJECT);
    462 		return;
    463 	}
    464 
    465 	if ((ap = findauthenticator(data[0], data[1])) != NULL) {
    466 		if (ap->is)
    467 			(*ap->is)(ap, data+2, cnt-2);
    468 	} else if (auth_debug_mode)
    469 		printf(">>>%s: Invalid authentication in IS: %d\r\n",
    470 			Name, *data);
    471 }
    472 
    473 void
    474 auth_reply(unsigned char *data, int cnt)
    475 {
    476 	Authenticator *ap;
    477 
    478 	if (cnt < 2)
    479 		return;
    480 
    481 	if ((ap = findauthenticator(data[0], data[1])) != NULL) {
    482 		if (ap->reply)
    483 			(*ap->reply)(ap, data+2, cnt-2);
    484 	} else if (auth_debug_mode)
    485 		printf(">>>%s: Invalid authentication in SEND: %d\r\n",
    486 			Name, *data);
    487 }
    488 
    489 void
    490 auth_name(unsigned char *data, int cnt)
    491 {
    492 	unsigned char savename[256];
    493 
    494 	if (cnt < 1) {
    495 		if (auth_debug_mode)
    496 			printf(">>>%s: Empty name in NAME\r\n", Name);
    497 		return;
    498 	}
    499 	if ((size_t)cnt > sizeof(savename) - 1) {
    500 		if (auth_debug_mode)
    501 			printf(">>>%s: Name in NAME (%d) exceeds %ld length\r\n",
    502 					Name, cnt, (long)sizeof(savename)-1);
    503 		return;
    504 	}
    505 	memmove((void *)savename, (void *)data, cnt);
    506 	savename[cnt] = '\0';	/* Null terminate */
    507 	if (auth_debug_mode)
    508 		printf(">>>%s: Got NAME [%s]\r\n", Name, savename);
    509 	auth_encrypt_user(savename);
    510 }
    511 
    512 int
    513 auth_sendname(unsigned char *cp, int len)
    514 {
    515 	static unsigned char str_request[256+6]
    516 			= { IAC, SB, TELOPT_AUTHENTICATION, TELQUAL_NAME, };
    517 	register unsigned char *e = str_request + 4;
    518 	register unsigned char *ee = &str_request[sizeof(str_request)-2];
    519 
    520 	while (--len >= 0) {
    521 		if ((*e++ = *cp++) == IAC)
    522 			*e++ = IAC;
    523 		if (e >= ee)
    524 			return(0);
    525 	}
    526 	*e++ = IAC;
    527 	*e++ = SE;
    528 	telnet_net_write(str_request, e - str_request);
    529 	printsub('>', &str_request[2], e - &str_request[2]);
    530 	return(1);
    531 }
    532 
    533 void
    534 auth_finished(Authenticator *ap, int result)
    535 {
    536 	if (!(authenticated = ap))
    537 		authenticated = &NoAuth;
    538 	validuser = result;
    539 }
    540 
    541 	/* ARGSUSED */
    542 static void
    543 auth_intr(int sig)
    544 {
    545 	auth_finished(0, AUTH_REJECT);
    546 }
    547 
    548 int
    549 auth_wait(char *name, size_t l)
    550 {
    551 	if (auth_debug_mode)
    552 		printf(">>>%s: in auth_wait.\r\n", Name);
    553 
    554 	if (Server && !authenticating)
    555 		return(0);
    556 
    557 	(void) signal(SIGALRM, auth_intr);
    558 	alarm(30);
    559 	while (!authenticated)
    560 		if (telnet_spin())
    561 			break;
    562 	alarm(0);
    563 	(void) signal(SIGALRM, SIG_DFL);
    564 
    565 	/*
    566 	 * Now check to see if the user is valid or not
    567 	 */
    568 	if (!authenticated || authenticated == &NoAuth)
    569 		return(AUTH_REJECT);
    570 
    571 	if (validuser == AUTH_VALID)
    572 		validuser = AUTH_USER;
    573 
    574 	if (authenticated->status)
    575 		validuser = (*authenticated->status)(authenticated,
    576 						     name, l, validuser);
    577 	return(validuser);
    578 }
    579 
    580 void
    581 auth_debug(int mode)
    582 {
    583 	auth_debug_mode = mode;
    584 }
    585 
    586 void
    587 auth_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
    588 {
    589 	Authenticator *ap;
    590 
    591 	if ((ap = findauthenticator(data[1], data[2])) && ap->printsub)
    592 		(*ap->printsub)(data, cnt, buf, buflen);
    593 	else
    594 		auth_gen_printsub(data, cnt, buf, buflen);
    595 }
    596 
    597 void
    598 auth_gen_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
    599 {
    600 	register unsigned char *cp;
    601 	unsigned char tbuf[16];
    602 
    603 	cnt -= 3;
    604 	data += 3;
    605 	buf[buflen-1] = '\0';
    606 	buf[buflen-2] = '*';
    607 	buflen -= 2;
    608 	for (; cnt > 0; cnt--, data++) {
    609 		snprintf((char *)tbuf, sizeof(tbuf), " %d", *data);
    610 		for (cp = tbuf; *cp && buflen > 0; --buflen)
    611 			*buf++ = *cp++;
    612 		if (buflen <= 0)
    613 			return;
    614 	}
    615 	*buf = '\0';
    616 }
    617 #endif
    618