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encrypt.c revision 1.1
      1 /*-
      2  * Copyright (c) 1991 The Regents of the University of California.
      3  * 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 #ifndef lint
     35 static char sccsid[] = "@(#)encrypt.c	5.2 (Berkeley) 3/22/91";
     36 #endif /* not lint */
     37 
     38 /*
     39  * Copyright (C) 1990 by the Massachusetts Institute of Technology
     40  *
     41  * Export of this software from the United States of America is assumed
     42  * to require a specific license from the United States Government.
     43  * It is the responsibility of any person or organization contemplating
     44  * export to obtain such a license before exporting.
     45  *
     46  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
     47  * distribute this software and its documentation for any purpose and
     48  * without fee is hereby granted, provided that the above copyright
     49  * notice appear in all copies and that both that copyright notice and
     50  * this permission notice appear in supporting documentation, and that
     51  * the name of M.I.T. not be used in advertising or publicity pertaining
     52  * to distribution of the software without specific, written prior
     53  * permission.  M.I.T. makes no representations about the suitability of
     54  * this software for any purpose.  It is provided "as is" without express
     55  * or implied warranty.
     56  */
     57 
     58 #if	defined(ENCRYPT)
     59 
     60 #define	ENCRYPT_NAMES
     61 #include <arpa/telnet.h>
     62 
     63 #include "encrypt.h"
     64 #include "misc.h"
     65 
     66 #ifdef	__STDC__
     67 #include <stdlib.h>
     68 #endif
     69 #ifdef	NO_STRING_H
     70 #include <strings.h>
     71 #else
     72 #include <string.h>
     73 #endif
     74 
     75 /*
     76  * These functions pointers point to the current routines
     77  * for encrypting and decrypting data.
     78  */
     79 void	(*encrypt_output) P((unsigned char *, int));
     80 int	(*decrypt_input) P((int));
     81 
     82 int encrypt_debug_mode = 0;
     83 static int decrypt_mode = 0;
     84 static int encrypt_mode = 0;
     85 static int encrypt_verbose = 0;
     86 static int autoencrypt = 0;
     87 static int autodecrypt = 0;
     88 static int havesessionkey = 0;
     89 static int Server = 0;
     90 static char *Name = "Noname";
     91 
     92 #define	typemask(x)	((x) > 0 ? 1 << ((x)-1) : 0)
     93 
     94 static long i_support_encrypt = typemask(ENCTYPE_DES_CFB64)
     95 				| typemask(ENCTYPE_DES_OFB64);
     96 static long i_support_decrypt = typemask(ENCTYPE_DES_CFB64)
     97 				| typemask(ENCTYPE_DES_OFB64);
     98 static long i_wont_support_encrypt = 0;
     99 static long i_wont_support_decrypt = 0;
    100 #define	I_SUPPORT_ENCRYPT	(i_support_encrypt & ~i_wont_support_encrypt)
    101 #define	I_SUPPORT_DECRYPT	(i_support_decrypt & ~i_wont_support_decrypt)
    102 
    103 static long remote_supports_encrypt = 0;
    104 static long remote_supports_decrypt = 0;
    105 
    106 static Encryptions encryptions[] = {
    107 #if	defined(DES_ENCRYPT)
    108     { "DES_CFB64",	ENCTYPE_DES_CFB64,
    109 			cfb64_encrypt,
    110 			cfb64_decrypt,
    111 			cfb64_init,
    112 			cfb64_start,
    113 			cfb64_is,
    114 			cfb64_reply,
    115 			cfb64_session,
    116 			cfb64_keyid,
    117 			cfb64_printsub },
    118     { "DES_OFB64",	ENCTYPE_DES_OFB64,
    119 			ofb64_encrypt,
    120 			ofb64_decrypt,
    121 			ofb64_init,
    122 			ofb64_start,
    123 			ofb64_is,
    124 			ofb64_reply,
    125 			ofb64_session,
    126 			ofb64_keyid,
    127 			ofb64_printsub },
    128 #endif
    129     { 0, },
    130 };
    131 
    132 static unsigned char str_send[64] = { IAC, SB, TELOPT_ENCRYPT,
    133 					 ENCRYPT_SUPPORT };
    134 static unsigned char str_suplen = 0;
    135 static unsigned char str_start[72] = { IAC, SB, TELOPT_ENCRYPT };
    136 static unsigned char str_end[] = { IAC, SB, TELOPT_ENCRYPT, 0, IAC, SE };
    137 
    138 	Encryptions *
    139 findencryption(type)
    140 	int type;
    141 {
    142 	Encryptions *ep = encryptions;
    143 
    144 	if (!(I_SUPPORT_ENCRYPT & remote_supports_decrypt & typemask(type)))
    145 		return(0);
    146 	while (ep->type && ep->type != type)
    147 		++ep;
    148 	return(ep->type ? ep : 0);
    149 }
    150 
    151 	Encryptions *
    152 finddecryption(type)
    153 	int type;
    154 {
    155 	Encryptions *ep = encryptions;
    156 
    157 	if (!(I_SUPPORT_DECRYPT & remote_supports_encrypt & typemask(type)))
    158 		return(0);
    159 	while (ep->type && ep->type != type)
    160 		++ep;
    161 	return(ep->type ? ep : 0);
    162 }
    163 
    164 #define	MAXKEYLEN 64
    165 
    166 static struct key_info {
    167 	unsigned char keyid[MAXKEYLEN];
    168 	int keylen;
    169 	int dir;
    170 	int *modep;
    171 	Encryptions *(*getcrypt)();
    172 } ki[2] = {
    173 	{ { 0 }, 0, DIR_ENCRYPT, &encrypt_mode, findencryption },
    174 	{ { 0 }, 0, DIR_DECRYPT, &decrypt_mode, finddecryption },
    175 };
    176 
    177 	void
    178 encrypt_init(name, server)
    179 	char *name;
    180 	int server;
    181 {
    182 	Encryptions *ep = encryptions;
    183 
    184 	Name = name;
    185 	Server = server;
    186 	i_support_encrypt = i_support_decrypt = 0;
    187 	remote_supports_encrypt = remote_supports_decrypt = 0;
    188 	encrypt_mode = 0;
    189 	decrypt_mode = 0;
    190 	encrypt_output = 0;
    191 	decrypt_input = 0;
    192 #ifdef notdef
    193 	encrypt_verbose = !server;
    194 #endif
    195 
    196 	str_suplen = 4;
    197 
    198 	while (ep->type) {
    199 		if (encrypt_debug_mode)
    200 			printf(">>>%s: I will support %s\r\n",
    201 				Name, ENCTYPE_NAME(ep->type));
    202 		i_support_encrypt |= typemask(ep->type);
    203 		i_support_decrypt |= typemask(ep->type);
    204 		if ((i_wont_support_decrypt & typemask(ep->type)) == 0)
    205 			if ((str_send[str_suplen++] = ep->type) == IAC)
    206 				str_send[str_suplen++] = IAC;
    207 		if (ep->init)
    208 			(*ep->init)(Server);
    209 		++ep;
    210 	}
    211 	str_send[str_suplen++] = IAC;
    212 	str_send[str_suplen++] = SE;
    213 }
    214 
    215 	void
    216 encrypt_list_types()
    217 {
    218 	Encryptions *ep = encryptions;
    219 
    220 	printf("Valid encryption types:\n");
    221 	while (ep->type) {
    222 		printf("\t%s (%d)\r\n", ENCTYPE_NAME(ep->type), ep->type);
    223 		++ep;
    224 	}
    225 }
    226 
    227 	int
    228 EncryptEnable(type, mode)
    229 	char *type, *mode;
    230 {
    231 	if (isprefix(type, "help") || isprefix(type, "?")) {
    232 		printf("Usage: encrypt enable <type> [input|output]\n");
    233 		encrypt_list_types();
    234 		return(0);
    235 	}
    236 	if (EncryptType(type, mode))
    237 		return(EncryptStart(mode));
    238 	return(0);
    239 }
    240 
    241 	int
    242 EncryptDisable(type, mode)
    243 	char *type, *mode;
    244 {
    245 	register Encryptions *ep;
    246 	int ret = 0;
    247 
    248 	if (isprefix(type, "help") || isprefix(type, "?")) {
    249 		printf("Usage: encrypt disable <type> [input|output]\n");
    250 		encrypt_list_types();
    251 	} else if ((ep = (Encryptions *)genget(type, encryptions,
    252 						sizeof(Encryptions))) == 0) {
    253 		printf("%s: invalid encryption type\n", type);
    254 	} else if (Ambiguous(ep)) {
    255 		printf("Ambiguous type '%s'\n", type);
    256 	} else {
    257 		if ((mode == 0) || (isprefix(mode, "input") ? 1 : 0)) {
    258 			if (decrypt_mode == ep->type)
    259 				EncryptStopInput();
    260 			i_wont_support_decrypt |= typemask(ep->type);
    261 			ret = 1;
    262 		}
    263 		if ((mode == 0) || (isprefix(mode, "output"))) {
    264 			if (encrypt_mode == ep->type)
    265 				EncryptStopOutput();
    266 			i_wont_support_encrypt |= typemask(ep->type);
    267 			ret = 1;
    268 		}
    269 		if (ret == 0)
    270 			printf("%s: invalid encryption mode\n", mode);
    271 	}
    272 	return(ret);
    273 }
    274 
    275 	int
    276 EncryptType(type, mode)
    277 	char *type;
    278 	char *mode;
    279 {
    280 	register Encryptions *ep;
    281 	int ret = 0;
    282 
    283 	if (isprefix(type, "help") || isprefix(type, "?")) {
    284 		printf("Usage: encrypt type <type> [input|output]\n");
    285 		encrypt_list_types();
    286 	} else if ((ep = (Encryptions *)genget(type, encryptions,
    287 						sizeof(Encryptions))) == 0) {
    288 		printf("%s: invalid encryption type\n", type);
    289 	} else if (Ambiguous(ep)) {
    290 		printf("Ambiguous type '%s'\n", type);
    291 	} else {
    292 		if ((mode == 0) || isprefix(mode, "input")) {
    293 			decrypt_mode = ep->type;
    294 			i_wont_support_decrypt &= ~typemask(ep->type);
    295 			ret = 1;
    296 		}
    297 		if ((mode == 0) || isprefix(mode, "output")) {
    298 			encrypt_mode = ep->type;
    299 			i_wont_support_encrypt &= ~typemask(ep->type);
    300 			ret = 1;
    301 		}
    302 		if (ret == 0)
    303 			printf("%s: invalid encryption mode\n", mode);
    304 	}
    305 	return(ret);
    306 }
    307 
    308 	int
    309 EncryptStart(mode)
    310 	char *mode;
    311 {
    312 	register int ret = 0;
    313 	if (mode) {
    314 		if (isprefix(mode, "input"))
    315 			return(EncryptStartInput());
    316 		if (isprefix(mode, "output"))
    317 			return(EncryptStartOutput());
    318 		if (isprefix(mode, "help") || isprefix(mode, "?")) {
    319 			printf("Usage: encrypt start [input|output]\n");
    320 			return(0);
    321 		}
    322 		printf("%s: invalid encryption mode 'encrypt start ?' for help\n", mode);
    323 		return(0);
    324 	}
    325 	ret += EncryptStartInput();
    326 	ret += EncryptStartOutput();
    327 	return(ret);
    328 }
    329 
    330 	int
    331 EncryptStartInput()
    332 {
    333 	if (decrypt_mode) {
    334 		encrypt_send_request_start();
    335 		return(1);
    336 	}
    337 	printf("No previous decryption mode, decryption not enabled\r\n");
    338 	return(0);
    339 }
    340 
    341 	int
    342 EncryptStartOutput()
    343 {
    344 	if (encrypt_mode) {
    345 		encrypt_start_output(encrypt_mode);
    346 		return(1);
    347 	}
    348 	printf("No previous encryption mode, encryption not enabled\r\n");
    349 	return(0);
    350 }
    351 
    352 	int
    353 EncryptStop(mode)
    354 	char *mode;
    355 {
    356 	int ret = 0;
    357 	if (mode) {
    358 		if (isprefix(mode, "input"))
    359 			return(EncryptStopInput());
    360 		if (isprefix(mode, "output"))
    361 			return(EncryptStopOutput());
    362 		if (isprefix(mode, "help") || isprefix(mode, "?")) {
    363 			printf("Usage: encrypt stop [input|output]\n");
    364 			return(0);
    365 		}
    366 		printf("%s: invalid encryption mode 'encrypt stop ?' for help\n", mode);
    367 		return(0);
    368 	}
    369 	ret += EncryptStopInput();
    370 	ret += EncryptStopOutput();
    371 	return(ret);
    372 }
    373 
    374 	int
    375 EncryptStopInput()
    376 {
    377 	encrypt_send_request_end();
    378 	return(1);
    379 }
    380 
    381 	int
    382 EncryptStopOutput()
    383 {
    384 	encrypt_send_end();
    385 	return(1);
    386 }
    387 
    388 	void
    389 encrypt_display()
    390 {
    391 	if (encrypt_output)
    392 		printf("Currently encrypting output with %s\r\n",
    393 			ENCTYPE_NAME(encrypt_mode));
    394 	if (decrypt_input)
    395 		printf("Currently decrypting input with %s\r\n",
    396 			ENCTYPE_NAME(decrypt_mode));
    397 }
    398 
    399 	int
    400 EncryptStatus()
    401 {
    402 	if (encrypt_output)
    403 		printf("Currently encrypting output with %s\r\n",
    404 			ENCTYPE_NAME(encrypt_mode));
    405 	else if (encrypt_mode) {
    406 		printf("Currently output is clear text.\r\n");
    407 		printf("Last encryption mode was %s\r\n",
    408 			ENCTYPE_NAME(encrypt_mode));
    409 	}
    410 	if (decrypt_input) {
    411 		printf("Currently decrypting input with %s\r\n",
    412 			ENCTYPE_NAME(decrypt_mode));
    413 	} else if (decrypt_mode) {
    414 		printf("Currently input is clear text.\r\n");
    415 		printf("Last decryption mode was %s\r\n",
    416 			ENCTYPE_NAME(decrypt_mode));
    417 	}
    418 	return 1;
    419 }
    420 
    421 	void
    422 encrypt_send_support()
    423 {
    424 	if (str_suplen) {
    425 		/*
    426 		 * If the user has requested that decryption start
    427 		 * immediatly, then send a "REQUEST START" before
    428 		 * we negotiate the type.
    429 		 */
    430 		if (!Server && autodecrypt)
    431 			encrypt_send_request_start();
    432 		net_write(str_send, str_suplen);
    433 		printsub('>', &str_send[2], str_suplen - 2);
    434 		str_suplen = 0;
    435 	}
    436 }
    437 
    438 	int
    439 EncryptDebug(on)
    440 	int on;
    441 {
    442 	if (on < 0)
    443 		encrypt_debug_mode ^= 1;
    444 	else
    445 		encrypt_debug_mode = on;
    446 	printf("Encryption debugging %s\r\n",
    447 		encrypt_debug_mode ? "enabled" : "disabled");
    448 	return(1);
    449 }
    450 
    451 	int
    452 EncryptVerbose(on)
    453 	int on;
    454 {
    455 	if (on < 0)
    456 		encrypt_verbose ^= 1;
    457 	else
    458 		encrypt_verbose = on;
    459 	printf("Encryption %s verbose\r\n",
    460 		encrypt_verbose ? "is" : "is not");
    461 	return(1);
    462 }
    463 
    464 	int
    465 EncryptAutoEnc(on)
    466 	int on;
    467 {
    468 	encrypt_auto(on);
    469 	printf("Automatic encryption of output is %s\r\n",
    470 		autoencrypt ? "enabled" : "disabled");
    471 	return(1);
    472 }
    473 
    474 	int
    475 EncryptAutoDec(on)
    476 	int on;
    477 {
    478 	decrypt_auto(on);
    479 	printf("Automatic decryption of input is %s\r\n",
    480 		autodecrypt ? "enabled" : "disabled");
    481 	return(1);
    482 }
    483 
    484 /*
    485  * Called when ENCRYPT SUPPORT is received.
    486  */
    487 	void
    488 encrypt_support(typelist, cnt)
    489 	unsigned char *typelist;
    490 	int cnt;
    491 {
    492 	register int type, use_type = 0;
    493 	Encryptions *ep;
    494 
    495 	/*
    496 	 * Forget anything the other side has previously told us.
    497 	 */
    498 	remote_supports_decrypt = 0;
    499 
    500 	while (cnt-- > 0) {
    501 		type = *typelist++;
    502 		if (encrypt_debug_mode)
    503 			printf(">>>%s: He is supporting %s (%d)\r\n",
    504 				Name,
    505 				ENCTYPE_NAME(type), type);
    506 		if ((type < ENCTYPE_CNT) &&
    507 		    (I_SUPPORT_ENCRYPT & typemask(type))) {
    508 			remote_supports_decrypt |= typemask(type);
    509 			if (use_type == 0)
    510 				use_type = type;
    511 		}
    512 	}
    513 	if (use_type) {
    514 		ep = findencryption(use_type);
    515 		if (!ep)
    516 			return;
    517 		type = ep->start ? (*ep->start)(DIR_ENCRYPT, Server) : 0;
    518 		if (encrypt_debug_mode)
    519 			printf(">>>%s: (*ep->start)() returned %d\r\n",
    520 					Name, type);
    521 		if (type < 0)
    522 			return;
    523 		encrypt_mode = use_type;
    524 		if (type == 0)
    525 			encrypt_start_output(use_type);
    526 	}
    527 }
    528 
    529 	void
    530 encrypt_is(data, cnt)
    531 	unsigned char *data;
    532 	int cnt;
    533 {
    534 	Encryptions *ep;
    535 	register int type, ret;
    536 
    537 	if (--cnt < 0)
    538 		return;
    539 	type = *data++;
    540 	if (type < ENCTYPE_CNT)
    541 		remote_supports_encrypt |= typemask(type);
    542 	if (!(ep = finddecryption(type))) {
    543 		if (encrypt_debug_mode)
    544 			printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
    545 				Name,
    546 				ENCTYPE_NAME_OK(type)
    547 					? ENCTYPE_NAME(type) : "(unknown)",
    548 				type);
    549 		return;
    550 	}
    551 	if (!ep->is) {
    552 		if (encrypt_debug_mode)
    553 			printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
    554 				Name,
    555 				ENCTYPE_NAME_OK(type)
    556 					? ENCTYPE_NAME(type) : "(unknown)",
    557 				type);
    558 		ret = 0;
    559 	} else {
    560 		ret = (*ep->is)(data, cnt);
    561 		if (encrypt_debug_mode)
    562 			printf("(*ep->is)(%x, %d) returned %s(%d)\n", data, cnt,
    563 				(ret < 0) ? "FAIL " :
    564 				(ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
    565 	}
    566 	if (ret < 0) {
    567 		autodecrypt = 0;
    568 	} else {
    569 		decrypt_mode = type;
    570 		if (ret == 0 && autodecrypt)
    571 			encrypt_send_request_start();
    572 	}
    573 }
    574 
    575 	void
    576 encrypt_reply(data, cnt)
    577 	unsigned char *data;
    578 	int cnt;
    579 {
    580 	Encryptions *ep;
    581 	register int ret, type;
    582 
    583 	if (--cnt < 0)
    584 		return;
    585 	type = *data++;
    586 	if (!(ep = findencryption(type))) {
    587 		if (encrypt_debug_mode)
    588 			printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
    589 				Name,
    590 				ENCTYPE_NAME_OK(type)
    591 					? ENCTYPE_NAME(type) : "(unknown)",
    592 				type);
    593 		return;
    594 	}
    595 	if (!ep->reply) {
    596 		if (encrypt_debug_mode)
    597 			printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
    598 				Name,
    599 				ENCTYPE_NAME_OK(type)
    600 					? ENCTYPE_NAME(type) : "(unknown)",
    601 				type);
    602 		ret = 0;
    603 	} else {
    604 		ret = (*ep->reply)(data, cnt);
    605 		if (encrypt_debug_mode)
    606 			printf("(*ep->reply)(%x, %d) returned %s(%d)\n",
    607 				data, cnt,
    608 				(ret < 0) ? "FAIL " :
    609 				(ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
    610 	}
    611 	if (encrypt_debug_mode)
    612 		printf(">>>%s: encrypt_reply returned %d\n", Name, ret);
    613 	if (ret < 0) {
    614 		autoencrypt = 0;
    615 	} else {
    616 		encrypt_mode = type;
    617 		if (ret == 0 && autoencrypt)
    618 			encrypt_start_output(type);
    619 	}
    620 }
    621 
    622 /*
    623  * Called when a ENCRYPT START command is received.
    624  */
    625 	void
    626 encrypt_start(data, cnt)
    627 	unsigned char *data;
    628 	int cnt;
    629 {
    630 	Encryptions *ep;
    631 
    632 	if (!decrypt_mode) {
    633 		/*
    634 		 * Something is wrong.  We should not get a START
    635 		 * command without having already picked our
    636 		 * decryption scheme.  Send a REQUEST-END to
    637 		 * attempt to clear the channel...
    638 		 */
    639 		printf("%s: Warning, Cannot decrypt input stream!!!\r\n", Name);
    640 		encrypt_send_request_end();
    641 		return;
    642 	}
    643 
    644 	if (ep = finddecryption(decrypt_mode)) {
    645 		decrypt_input = ep->input;
    646 		if (encrypt_verbose)
    647 			printf("[ Input is now decrypted with type %s ]\r\n",
    648 				ENCTYPE_NAME(decrypt_mode));
    649 		if (encrypt_debug_mode)
    650 			printf(">>>%s: Start to decrypt input with type %s\r\n",
    651 				Name, ENCTYPE_NAME(decrypt_mode));
    652 	} else {
    653 		printf("%s: Warning, Cannot decrypt type %s (%d)!!!\r\n",
    654 				Name,
    655 				ENCTYPE_NAME_OK(decrypt_mode)
    656 					? ENCTYPE_NAME(decrypt_mode)
    657 					: "(unknown)",
    658 				decrypt_mode);
    659 		encrypt_send_request_end();
    660 	}
    661 }
    662 
    663 	void
    664 encrypt_session_key(key, server)
    665 	Session_Key *key;
    666 	int server;
    667 {
    668 	Encryptions *ep = encryptions;
    669 
    670 	havesessionkey = 1;
    671 
    672 	while (ep->type) {
    673 		if (ep->session)
    674 			(*ep->session)(key, server);
    675 		++ep;
    676 	}
    677 }
    678 
    679 /*
    680  * Called when ENCRYPT END is received.
    681  */
    682 	void
    683 encrypt_end()
    684 {
    685 	decrypt_input = 0;
    686 	if (encrypt_debug_mode)
    687 		printf(">>>%s: Input is back to clear text\r\n", Name);
    688 	if (encrypt_verbose)
    689 		printf("[ Input is now clear text ]\r\n");
    690 }
    691 
    692 /*
    693  * Called when ENCRYPT REQUEST-END is received.
    694  */
    695 	void
    696 encrypt_request_end()
    697 {
    698 	encrypt_send_end();
    699 }
    700 
    701 /*
    702  * Called when ENCRYPT REQUEST-START is received.  If we receive
    703  * this before a type is picked, then that indicates that the
    704  * other side wants us to start encrypting data as soon as we
    705  * can.
    706  */
    707 	void
    708 encrypt_request_start(data, cnt)
    709 	unsigned char *data;
    710 	int cnt;
    711 {
    712 	if (encrypt_mode == 0)  {
    713 		if (Server)
    714 			autoencrypt = 1;
    715 		return;
    716 	}
    717 	encrypt_start_output(encrypt_mode);
    718 }
    719 
    720 static unsigned char str_keyid[(MAXKEYLEN*2)+5] = { IAC, SB, TELOPT_ENCRYPT };
    721 
    722 encrypt_enc_keyid(keyid, len)
    723 	unsigned char *keyid;
    724 	int len;
    725 {
    726 	encrypt_keyid(&ki[1], keyid, len);
    727 }
    728 
    729 encrypt_dec_keyid(keyid, len)
    730 	unsigned char *keyid;
    731 	int len;
    732 {
    733 	encrypt_keyid(&ki[0], keyid, len);
    734 }
    735 
    736 encrypt_keyid(kp, keyid, len)
    737 	struct key_info *kp;
    738 	unsigned char *keyid;
    739 	int len;
    740 {
    741 	Encryptions *ep;
    742 	unsigned char *strp, *cp;
    743 	int dir = kp->dir;
    744 	register int ret = 0;
    745 
    746 	if (!(ep = (*kp->getcrypt)(*kp->modep))) {
    747 		if (len == 0)
    748 			return;
    749 		kp->keylen = 0;
    750 	} else if (len == 0) {
    751 		/*
    752 		 * Empty option, indicates a failure.
    753 		 */
    754 		if (kp->keylen == 0)
    755 			return;
    756 		kp->keylen = 0;
    757 		if (ep->keyid)
    758 			(void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
    759 
    760 	} else if ((len != kp->keylen) || (bcmp(keyid, kp->keyid, len) != 0)) {
    761 		/*
    762 		 * Length or contents are different
    763 		 */
    764 		kp->keylen = len;
    765 		bcopy(keyid, kp->keyid, len);
    766 		if (ep->keyid)
    767 			(void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
    768 	} else {
    769 		if (ep->keyid)
    770 			ret = (*ep->keyid)(dir, kp->keyid, &kp->keylen);
    771 		if ((ret == 0) && (dir == DIR_ENCRYPT) && autoencrypt)
    772 			encrypt_start_output(*kp->modep);
    773 		return;
    774 	}
    775 
    776 	encrypt_send_keyid(dir, kp->keyid, kp->keylen, 0);
    777 }
    778 
    779 	void
    780 encrypt_send_keyid(dir, keyid, keylen, saveit)
    781 	int dir;
    782 	unsigned char *keyid;
    783 	int keylen;
    784 	int saveit;
    785 {
    786 	unsigned char *strp;
    787 
    788 	str_keyid[3] = (dir == DIR_ENCRYPT)
    789 			? ENCRYPT_ENC_KEYID : ENCRYPT_DEC_KEYID;
    790 	if (saveit) {
    791 		struct key_info *kp = &ki[(dir == DIR_ENCRYPT) ? 0 : 1];
    792 		bcopy(keyid, kp->keyid, keylen);
    793 		kp->keylen = keylen;
    794 	}
    795 
    796 	for (strp = &str_keyid[4]; keylen > 0; --keylen) {
    797 		if ((*strp++ = *keyid++) == IAC)
    798 			*strp++ = IAC;
    799 	}
    800 	*strp++ = IAC;
    801 	*strp++ = SE;
    802 	net_write(str_keyid, strp - str_keyid);
    803 	printsub('>', &str_keyid[2], strp - str_keyid - 2);
    804 }
    805 
    806 	void
    807 encrypt_auto(on)
    808 	int on;
    809 {
    810 	if (on < 0)
    811 		autoencrypt ^= 1;
    812 	else
    813 		autoencrypt = on ? 1 : 0;
    814 }
    815 
    816 	void
    817 decrypt_auto(on)
    818 	int on;
    819 {
    820 	if (on < 0)
    821 		autodecrypt ^= 1;
    822 	else
    823 		autodecrypt = on ? 1 : 0;
    824 }
    825 
    826 	void
    827 encrypt_start_output(type)
    828 	int type;
    829 {
    830 	Encryptions *ep;
    831 	register unsigned char *p;
    832 	register int i;
    833 
    834 	if (!(ep = findencryption(type))) {
    835 		if (encrypt_debug_mode) {
    836 			printf(">>>%s: Can't encrypt with type %s (%d)\r\n",
    837 				Name,
    838 				ENCTYPE_NAME_OK(type)
    839 					? ENCTYPE_NAME(type) : "(unknown)",
    840 				type);
    841 		}
    842 		return;
    843 	}
    844 	if (ep->start) {
    845 		i = (*ep->start)(DIR_ENCRYPT, Server);
    846 		if (encrypt_debug_mode) {
    847 			printf(">>>%s: Encrypt start: %s (%d) %s\r\n",
    848 				Name,
    849 				(i < 0) ? "failed" :
    850 					"initial negotiation in progress",
    851 				i, ENCTYPE_NAME(type));
    852 		}
    853 		if (i)
    854 			return;
    855 	}
    856 	p = str_start + 3;
    857 	*p++ = ENCRYPT_START;
    858 	for (i = 0; i < ki[0].keylen; ++i) {
    859 		if ((*p++ = ki[0].keyid[i]) == IAC)
    860 			*p++ = IAC;
    861 	}
    862 	*p++ = IAC;
    863 	*p++ = SE;
    864 	net_write(str_start, p - str_start);
    865 	net_encrypt();
    866 	printsub('>', &str_start[2], p - &str_start[2]);
    867 	/*
    868 	 * If we are already encrypting in some mode, then
    869 	 * encrypt the ring (which includes our request) in
    870 	 * the old mode, mark it all as "clear text" and then
    871 	 * switch to the new mode.
    872 	 */
    873 	encrypt_output = ep->output;
    874 	encrypt_mode = type;
    875 	if (encrypt_debug_mode)
    876 		printf(">>>%s: Started to encrypt output with type %s\r\n",
    877 			Name, ENCTYPE_NAME(type));
    878 	if (encrypt_verbose)
    879 		printf("[ Output is now encrypted with type %s ]\r\n",
    880 			ENCTYPE_NAME(type));
    881 }
    882 
    883 	void
    884 encrypt_send_end()
    885 {
    886 	if (!encrypt_output)
    887 		return;
    888 
    889 	str_end[3] = ENCRYPT_END;
    890 	net_write(str_end, sizeof(str_end));
    891 	net_encrypt();
    892 	printsub('>', &str_end[2], sizeof(str_end) - 2);
    893 	/*
    894 	 * Encrypt the output buffer now because it will not be done by
    895 	 * netflush...
    896 	 */
    897 	encrypt_output = 0;
    898 	if (encrypt_debug_mode)
    899 		printf(">>>%s: Output is back to clear text\r\n", Name);
    900 	if (encrypt_verbose)
    901 		printf("[ Output is now clear text ]\r\n");
    902 }
    903 
    904 	void
    905 encrypt_send_request_start()
    906 {
    907 	register unsigned char *p;
    908 	register int i;
    909 
    910 	p = &str_start[3];
    911 	*p++ = ENCRYPT_REQSTART;
    912 	for (i = 0; i < ki[1].keylen; ++i) {
    913 		if ((*p++ = ki[1].keyid[i]) == IAC)
    914 			*p++ = IAC;
    915 	}
    916 	*p++ = IAC;
    917 	*p++ = SE;
    918 	net_write(str_start, p - str_start);
    919 	printsub('>', &str_start[2], p - &str_start[2]);
    920 	if (encrypt_debug_mode)
    921 		printf(">>>%s: Request input to be encrypted\r\n", Name);
    922 }
    923 
    924 	void
    925 encrypt_send_request_end()
    926 {
    927 	str_end[3] = ENCRYPT_REQEND;
    928 	net_write(str_end, sizeof(str_end));
    929 	printsub('>', &str_end[2], sizeof(str_end) - 2);
    930 
    931 	if (encrypt_debug_mode)
    932 		printf(">>>%s: Request input to be clear text\r\n", Name);
    933 }
    934 
    935 	void
    936 encrypt_wait()
    937 {
    938 	register int encrypt, decrypt;
    939 	if (encrypt_debug_mode)
    940 		printf(">>>%s: in encrypt_wait\r\n", Name);
    941 	if (!havesessionkey || !(I_SUPPORT_ENCRYPT & remote_supports_decrypt))
    942 		return;
    943 	while (autoencrypt && !encrypt_output)
    944 		if (telnet_spin())
    945 			return;
    946 }
    947 
    948 	void
    949 encrypt_debug(mode)
    950 	int mode;
    951 {
    952 	encrypt_debug_mode = mode;
    953 }
    954 
    955 	void
    956 encrypt_gen_printsub(data, cnt, buf, buflen)
    957 	unsigned char *data, *buf;
    958 	int cnt, buflen;
    959 {
    960 	char tbuf[16], *cp;
    961 
    962 	cnt -= 2;
    963 	data += 2;
    964 	buf[buflen-1] = '\0';
    965 	buf[buflen-2] = '*';
    966 	buflen -= 2;;
    967 	for (; cnt > 0; cnt--, data++) {
    968 		sprintf(tbuf, " %d", *data);
    969 		for (cp = tbuf; *cp && buflen > 0; --buflen)
    970 			*buf++ = *cp++;
    971 		if (buflen <= 0)
    972 			return;
    973 	}
    974 	*buf = '\0';
    975 }
    976 
    977 	void
    978 encrypt_printsub(data, cnt, buf, buflen)
    979 	unsigned char *data, *buf;
    980 	int cnt, buflen;
    981 {
    982 	Encryptions *ep;
    983 	register int type = data[1];
    984 
    985 	for (ep = encryptions; ep->type && ep->type != type; ep++)
    986 		;
    987 
    988 	if (ep->printsub)
    989 		(*ep->printsub)(data, cnt, buf, buflen);
    990 	else
    991 		encrypt_gen_printsub(data, cnt, buf, buflen);
    992 }
    993 #endif
    994