xref: /dragonfly/lib/libtelnet/encrypt.c (revision e0ecab34)
1 /*-
2  * Copyright (c) 1991, 1993
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  * @(#)encrypt.c	8.2 (Berkeley) 5/30/95
34  * $FreeBSD: src/crypto/telnet/libtelnet/encrypt.c,v 1.3.2.2 2002/04/13 10:59:07 markm Exp $
35  * $DragonFly: src/crypto/telnet/libtelnet/encrypt.c,v 1.2 2003/06/17 04:24:37 dillon Exp $
36  */
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 #ifdef	ENCRYPTION
59 
60 #define	ENCRYPT_NAMES
61 #include <arpa/telnet.h>
62 #include <stdio.h>
63 #include <stdlib.h>
64 #include <string.h>
65 
66 #include "encrypt.h"
67 #include "misc.h"
68 
69 /*
70  * These functions pointers point to the current routines
71  * for encrypting and decrypting data.
72  */
73 void	(*encrypt_output)(unsigned char *, int);
74 int	(*decrypt_input)(int);
75 
76 int EncryptType(char *type, char *mode);
77 int EncryptStart(char *mode);
78 int EncryptStop(char *mode);
79 int EncryptStartInput(void);
80 int EncryptStartOutput(void);
81 int EncryptStopInput(void);
82 int EncryptStopOutput(void);
83 
84 int encrypt_debug_mode = 0;
85 static int decrypt_mode = 0;
86 static int encrypt_mode = 0;
87 static int encrypt_verbose = 0;
88 static int autoencrypt = 0;
89 static int autodecrypt = 0;
90 static int havesessionkey = 0;
91 static int Server = 0;
92 static const char *Name = "Noname";
93 
94 #define	typemask(x)	((x) > 0 ? 1 << ((x)-1) : 0)
95 
96 static long i_support_encrypt = 0
97  | typemask(ENCTYPE_DES_CFB64) | typemask(ENCTYPE_DES_OFB64)
98  |0;
99 static long i_support_decrypt = 0
100  | typemask(ENCTYPE_DES_CFB64) | typemask(ENCTYPE_DES_OFB64)
101  |0;
102 
103 static long i_wont_support_encrypt = 0;
104 static long i_wont_support_decrypt = 0;
105 #define	I_SUPPORT_ENCRYPT	(i_support_encrypt & ~i_wont_support_encrypt)
106 #define	I_SUPPORT_DECRYPT	(i_support_decrypt & ~i_wont_support_decrypt)
107 
108 static long remote_supports_encrypt = 0;
109 static long remote_supports_decrypt = 0;
110 
111 static Encryptions encryptions[] = {
112     { "DES_CFB64",	ENCTYPE_DES_CFB64,
113 			cfb64_encrypt,
114 			cfb64_decrypt,
115 			cfb64_init,
116 			cfb64_start,
117 			cfb64_is,
118 			cfb64_reply,
119 			cfb64_session,
120 			cfb64_keyid,
121 			cfb64_printsub },
122     { "DES_OFB64",	ENCTYPE_DES_OFB64,
123 			ofb64_encrypt,
124 			ofb64_decrypt,
125 			ofb64_init,
126 			ofb64_start,
127 			ofb64_is,
128 			ofb64_reply,
129 			ofb64_session,
130 			ofb64_keyid,
131 			ofb64_printsub },
132     { NULL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
133 };
134 
135 static unsigned char str_send[64] = { IAC, SB, TELOPT_ENCRYPT,
136 					 ENCRYPT_SUPPORT };
137 static unsigned char str_suplen = 0;
138 static unsigned char str_start[72] = { IAC, SB, TELOPT_ENCRYPT };
139 static unsigned char str_end[] = { IAC, SB, TELOPT_ENCRYPT, 0, IAC, SE };
140 
141 Encryptions *
142 findencryption(int type)
143 {
144 	Encryptions *ep = encryptions;
145 
146 	if (!(I_SUPPORT_ENCRYPT & remote_supports_decrypt & (unsigned)typemask(type)))
147 		return(0);
148 	while (ep->type && ep->type != type)
149 		++ep;
150 	return(ep->type ? ep : 0);
151 }
152 
153 static Encryptions *
154 finddecryption(int type)
155 {
156 	Encryptions *ep = encryptions;
157 
158 	if (!(I_SUPPORT_DECRYPT & remote_supports_encrypt & (unsigned)typemask(type)))
159 		return(0);
160 	while (ep->type && ep->type != type)
161 		++ep;
162 	return(ep->type ? ep : 0);
163 }
164 
165 #define	MAXKEYLEN 64
166 
167 static struct key_info {
168 	unsigned char keyid[MAXKEYLEN];
169 	int keylen;
170 	int dir;
171 	int *modep;
172 	Encryptions *(*getcrypt)(int);
173 } ki[2] = {
174 	{ { 0 }, 0, DIR_ENCRYPT, &encrypt_mode, findencryption },
175 	{ { 0 }, 0, DIR_DECRYPT, &decrypt_mode, finddecryption },
176 };
177 
178 static void encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len);
179 
180 void
181 encrypt_init(const char *name, int server)
182 {
183 	Encryptions *ep = encryptions;
184 
185 	Name = name;
186 	Server = server;
187 	i_support_encrypt = i_support_decrypt = 0;
188 	remote_supports_encrypt = remote_supports_decrypt = 0;
189 	encrypt_mode = 0;
190 	decrypt_mode = 0;
191 	encrypt_output = 0;
192 	decrypt_input = 0;
193 
194 	str_suplen = 4;
195 
196 	while (ep->type) {
197 		if (encrypt_debug_mode)
198 			printf(">>>%s: I will support %s\r\n",
199 				Name, ENCTYPE_NAME(ep->type));
200 		i_support_encrypt |= typemask(ep->type);
201 		i_support_decrypt |= typemask(ep->type);
202 		if ((i_wont_support_decrypt & typemask(ep->type)) == 0)
203 			if ((str_send[str_suplen++] = ep->type) == IAC)
204 				str_send[str_suplen++] = IAC;
205 		if (ep->init)
206 			(*ep->init)(Server);
207 		++ep;
208 	}
209 	str_send[str_suplen++] = IAC;
210 	str_send[str_suplen++] = SE;
211 }
212 
213 static void
214 encrypt_list_types(void)
215 {
216 	Encryptions *ep = encryptions;
217 
218 	printf("Valid encryption types:\n");
219 	while (ep->type) {
220 		printf("\t%s (%d)\r\n", ENCTYPE_NAME(ep->type), ep->type);
221 		++ep;
222 	}
223 }
224 
225 int
226 EncryptEnable(char *type, char *mode)
227 {
228 	if (isprefix(type, "help") || isprefix(type, "?")) {
229 		printf("Usage: encrypt enable <type> [input|output]\n");
230 		encrypt_list_types();
231 		return(0);
232 	}
233 	if (EncryptType(type, mode))
234 		return(EncryptStart(mode));
235 	return(0);
236 }
237 
238 int
239 EncryptDisable(char *type, char *mode)
240 {
241 	Encryptions *ep;
242 	int ret = 0;
243 
244 	if (isprefix(type, "help") || isprefix(type, "?")) {
245 		printf("Usage: encrypt disable <type> [input|output]\n");
246 		encrypt_list_types();
247 	} else if ((ep = (Encryptions *)genget(type, (char **)encryptions,
248 						sizeof(Encryptions))) == 0) {
249 		printf("%s: invalid encryption type\n", type);
250 	} else if (Ambiguous((char **)ep)) {
251 		printf("Ambiguous type '%s'\n", type);
252 	} else {
253 		if ((mode == 0) || (isprefix(mode, "input") ? 1 : 0)) {
254 			if (decrypt_mode == ep->type)
255 				EncryptStopInput();
256 			i_wont_support_decrypt |= typemask(ep->type);
257 			ret = 1;
258 		}
259 		if ((mode == 0) || (isprefix(mode, "output"))) {
260 			if (encrypt_mode == ep->type)
261 				EncryptStopOutput();
262 			i_wont_support_encrypt |= typemask(ep->type);
263 			ret = 1;
264 		}
265 		if (ret == 0)
266 			printf("%s: invalid encryption mode\n", mode);
267 	}
268 	return(ret);
269 }
270 
271 int
272 EncryptType(char *type, char *mode)
273 {
274 	Encryptions *ep;
275 	int ret = 0;
276 
277 	if (isprefix(type, "help") || isprefix(type, "?")) {
278 		printf("Usage: encrypt type <type> [input|output]\n");
279 		encrypt_list_types();
280 	} else if ((ep = (Encryptions *)genget(type, (char **)encryptions,
281 						sizeof(Encryptions))) == 0) {
282 		printf("%s: invalid encryption type\n", type);
283 	} else if (Ambiguous((char **)ep)) {
284 		printf("Ambiguous type '%s'\n", type);
285 	} else {
286 		if ((mode == 0) || isprefix(mode, "input")) {
287 			decrypt_mode = ep->type;
288 			i_wont_support_decrypt &= ~typemask(ep->type);
289 			ret = 1;
290 		}
291 		if ((mode == 0) || isprefix(mode, "output")) {
292 			encrypt_mode = ep->type;
293 			i_wont_support_encrypt &= ~typemask(ep->type);
294 			ret = 1;
295 		}
296 		if (ret == 0)
297 			printf("%s: invalid encryption mode\n", mode);
298 	}
299 	return(ret);
300 }
301 
302 int
303 EncryptStart(char *mode)
304 {
305 	int ret = 0;
306 	if (mode) {
307 		if (isprefix(mode, "input"))
308 			return(EncryptStartInput());
309 		if (isprefix(mode, "output"))
310 			return(EncryptStartOutput());
311 		if (isprefix(mode, "help") || isprefix(mode, "?")) {
312 			printf("Usage: encrypt start [input|output]\n");
313 			return(0);
314 		}
315 		printf("%s: invalid encryption mode 'encrypt start ?' for help\n", mode);
316 		return(0);
317 	}
318 	ret += EncryptStartInput();
319 	ret += EncryptStartOutput();
320 	return(ret);
321 }
322 
323 int
324 EncryptStartInput(void)
325 {
326 	if (decrypt_mode) {
327 		encrypt_send_request_start();
328 		return(1);
329 	}
330 	printf("No previous decryption mode, decryption not enabled\r\n");
331 	return(0);
332 }
333 
334 int
335 EncryptStartOutput(void)
336 {
337 	if (encrypt_mode) {
338 		encrypt_start_output(encrypt_mode);
339 		return(1);
340 	}
341 	printf("No previous encryption mode, encryption not enabled\r\n");
342 	return(0);
343 }
344 
345 int
346 EncryptStop(char *mode)
347 {
348 	int ret = 0;
349 	if (mode) {
350 		if (isprefix(mode, "input"))
351 			return(EncryptStopInput());
352 		if (isprefix(mode, "output"))
353 			return(EncryptStopOutput());
354 		if (isprefix(mode, "help") || isprefix(mode, "?")) {
355 			printf("Usage: encrypt stop [input|output]\n");
356 			return(0);
357 		}
358 		printf("%s: invalid encryption mode 'encrypt stop ?' for help\n", mode);
359 		return(0);
360 	}
361 	ret += EncryptStopInput();
362 	ret += EncryptStopOutput();
363 	return(ret);
364 }
365 
366 int
367 EncryptStopInput(void)
368 {
369 	encrypt_send_request_end();
370 	return(1);
371 }
372 
373 int
374 EncryptStopOutput(void)
375 {
376 	encrypt_send_end();
377 	return(1);
378 }
379 
380 void
381 encrypt_display(void)
382 {
383 	if (encrypt_output)
384 		printf("Currently encrypting output with %s\r\n",
385 			ENCTYPE_NAME(encrypt_mode));
386 	if (decrypt_input)
387 		printf("Currently decrypting input with %s\r\n",
388 			ENCTYPE_NAME(decrypt_mode));
389 }
390 
391 int
392 EncryptStatus(void)
393 {
394 	if (encrypt_output)
395 		printf("Currently encrypting output with %s\r\n",
396 			ENCTYPE_NAME(encrypt_mode));
397 	else if (encrypt_mode) {
398 		printf("Currently output is clear text.\r\n");
399 		printf("Last encryption mode was %s\r\n",
400 			ENCTYPE_NAME(encrypt_mode));
401 	}
402 	if (decrypt_input) {
403 		printf("Currently decrypting input with %s\r\n",
404 			ENCTYPE_NAME(decrypt_mode));
405 	} else if (decrypt_mode) {
406 		printf("Currently input is clear text.\r\n");
407 		printf("Last decryption mode was %s\r\n",
408 			ENCTYPE_NAME(decrypt_mode));
409 	}
410 	return 1;
411 }
412 
413 void
414 encrypt_send_support(void)
415 {
416 	if (str_suplen) {
417 		/*
418 		 * If the user has requested that decryption start
419 		 * immediatly, then send a "REQUEST START" before
420 		 * we negotiate the type.
421 		 */
422 		if (!Server && autodecrypt)
423 			encrypt_send_request_start();
424 		net_write(str_send, str_suplen);
425 		printsub('>', &str_send[2], str_suplen - 2);
426 		str_suplen = 0;
427 	}
428 }
429 
430 int
431 EncryptDebug(int on)
432 {
433 	if (on < 0)
434 		encrypt_debug_mode ^= 1;
435 	else
436 		encrypt_debug_mode = on;
437 	printf("Encryption debugging %s\r\n",
438 		encrypt_debug_mode ? "enabled" : "disabled");
439 	return(1);
440 }
441 
442 int
443 EncryptVerbose(int on)
444 {
445 	if (on < 0)
446 		encrypt_verbose ^= 1;
447 	else
448 		encrypt_verbose = on;
449 	printf("Encryption %s verbose\r\n",
450 		encrypt_verbose ? "is" : "is not");
451 	return(1);
452 }
453 
454 int
455 EncryptAutoEnc(int on)
456 {
457 	encrypt_auto(on);
458 	printf("Automatic encryption of output is %s\r\n",
459 		autoencrypt ? "enabled" : "disabled");
460 	return(1);
461 }
462 
463 int
464 EncryptAutoDec(int on)
465 {
466 	decrypt_auto(on);
467 	printf("Automatic decryption of input is %s\r\n",
468 		autodecrypt ? "enabled" : "disabled");
469 	return(1);
470 }
471 
472 /*
473  * Called when ENCRYPT SUPPORT is received.
474  */
475 void
476 encrypt_support(unsigned char *typelist, int cnt)
477 {
478 	int type, use_type = 0;
479 	Encryptions *ep;
480 
481 	/*
482 	 * Forget anything the other side has previously told us.
483 	 */
484 	remote_supports_decrypt = 0;
485 
486 	while (cnt-- > 0) {
487 		type = *typelist++;
488 		if (encrypt_debug_mode)
489 			printf(">>>%s: He is supporting %s (%d)\r\n",
490 				Name,
491 				ENCTYPE_NAME(type), type);
492 		if ((type < ENCTYPE_CNT) &&
493 		    (I_SUPPORT_ENCRYPT & typemask(type))) {
494 			remote_supports_decrypt |= typemask(type);
495 			if (use_type == 0)
496 				use_type = type;
497 		}
498 	}
499 	if (use_type) {
500 		ep = findencryption(use_type);
501 		if (!ep)
502 			return;
503 		type = ep->start ? (*ep->start)(DIR_ENCRYPT, Server) : 0;
504 		if (encrypt_debug_mode)
505 			printf(">>>%s: (*ep->start)() returned %d\r\n",
506 					Name, type);
507 		if (type < 0)
508 			return;
509 		encrypt_mode = use_type;
510 		if (type == 0)
511 			encrypt_start_output(use_type);
512 	}
513 }
514 
515 void
516 encrypt_is(unsigned char *data, int cnt)
517 {
518 	Encryptions *ep;
519 	int type, ret;
520 
521 	if (--cnt < 0)
522 		return;
523 	type = *data++;
524 	if (type < ENCTYPE_CNT)
525 		remote_supports_encrypt |= typemask(type);
526 	if (!(ep = finddecryption(type))) {
527 		if (encrypt_debug_mode)
528 			printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
529 				Name,
530 				ENCTYPE_NAME_OK(type)
531 					? ENCTYPE_NAME(type) : "(unknown)",
532 				type);
533 		return;
534 	}
535 	if (!ep->is) {
536 		if (encrypt_debug_mode)
537 			printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
538 				Name,
539 				ENCTYPE_NAME_OK(type)
540 					? ENCTYPE_NAME(type) : "(unknown)",
541 				type);
542 		ret = 0;
543 	} else {
544 		ret = (*ep->is)(data, cnt);
545 		if (encrypt_debug_mode)
546 			printf("(*ep->is)(%p, %d) returned %s(%d)\n", data, cnt,
547 				(ret < 0) ? "FAIL " :
548 				(ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
549 	}
550 	if (ret < 0) {
551 		autodecrypt = 0;
552 	} else {
553 		decrypt_mode = type;
554 		if (ret == 0 && autodecrypt)
555 			encrypt_send_request_start();
556 	}
557 }
558 
559 void
560 encrypt_reply(unsigned char *data, int cnt)
561 {
562 	Encryptions *ep;
563 	int ret, type;
564 
565 	if (--cnt < 0)
566 		return;
567 	type = *data++;
568 	if (!(ep = findencryption(type))) {
569 		if (encrypt_debug_mode)
570 			printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
571 				Name,
572 				ENCTYPE_NAME_OK(type)
573 					? ENCTYPE_NAME(type) : "(unknown)",
574 				type);
575 		return;
576 	}
577 	if (!ep->reply) {
578 		if (encrypt_debug_mode)
579 			printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
580 				Name,
581 				ENCTYPE_NAME_OK(type)
582 					? ENCTYPE_NAME(type) : "(unknown)",
583 				type);
584 		ret = 0;
585 	} else {
586 		ret = (*ep->reply)(data, cnt);
587 		if (encrypt_debug_mode)
588 			printf("(*ep->reply)(%p, %d) returned %s(%d)\n",
589 				data, cnt,
590 				(ret < 0) ? "FAIL " :
591 				(ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
592 	}
593 	if (encrypt_debug_mode)
594 		printf(">>>%s: encrypt_reply returned %d\n", Name, ret);
595 	if (ret < 0) {
596 		autoencrypt = 0;
597 	} else {
598 		encrypt_mode = type;
599 		if (ret == 0 && autoencrypt)
600 			encrypt_start_output(type);
601 	}
602 }
603 
604 /*
605  * Called when a ENCRYPT START command is received.
606  */
607 void
608 encrypt_start(unsigned char *data __unused, int cnt __unused)
609 {
610 	Encryptions *ep;
611 
612 	if (!decrypt_mode) {
613 		/*
614 		 * Something is wrong.  We should not get a START
615 		 * command without having already picked our
616 		 * decryption scheme.  Send a REQUEST-END to
617 		 * attempt to clear the channel...
618 		 */
619 		printf("%s: Warning, Cannot decrypt input stream!!!\r\n", Name);
620 		encrypt_send_request_end();
621 		return;
622 	}
623 
624 	if ((ep = finddecryption(decrypt_mode))) {
625 		decrypt_input = ep->input;
626 		if (encrypt_verbose)
627 			printf("[ Input is now decrypted with type %s ]\r\n",
628 				ENCTYPE_NAME(decrypt_mode));
629 		if (encrypt_debug_mode)
630 			printf(">>>%s: Start to decrypt input with type %s\r\n",
631 				Name, ENCTYPE_NAME(decrypt_mode));
632 	} else {
633 		printf("%s: Warning, Cannot decrypt type %s (%d)!!!\r\n",
634 				Name,
635 				ENCTYPE_NAME_OK(decrypt_mode)
636 					? ENCTYPE_NAME(decrypt_mode)
637 					: "(unknown)",
638 				decrypt_mode);
639 		encrypt_send_request_end();
640 	}
641 }
642 
643 void
644 encrypt_session_key( Session_Key *key, int server)
645 {
646 	Encryptions *ep = encryptions;
647 
648 	havesessionkey = 1;
649 
650 	while (ep->type) {
651 		if (ep->session)
652 			(*ep->session)(key, server);
653 		++ep;
654 	}
655 }
656 
657 /*
658  * Called when ENCRYPT END is received.
659  */
660 void
661 encrypt_end(void)
662 {
663 	decrypt_input = 0;
664 	if (encrypt_debug_mode)
665 		printf(">>>%s: Input is back to clear text\r\n", Name);
666 	if (encrypt_verbose)
667 		printf("[ Input is now clear text ]\r\n");
668 }
669 
670 /*
671  * Called when ENCRYPT REQUEST-END is received.
672  */
673 void
674 encrypt_request_end(void)
675 {
676 	encrypt_send_end();
677 }
678 
679 /*
680  * Called when ENCRYPT REQUEST-START is received.  If we receive
681  * this before a type is picked, then that indicates that the
682  * other side wants us to start encrypting data as soon as we
683  * can.
684  */
685 void
686 encrypt_request_start(unsigned char *data __unused, int cnt __unused)
687 {
688 	if (encrypt_mode == 0)  {
689 		if (Server)
690 			autoencrypt = 1;
691 		return;
692 	}
693 	encrypt_start_output(encrypt_mode);
694 }
695 
696 static unsigned char str_keyid[(MAXKEYLEN*2)+5] = { IAC, SB, TELOPT_ENCRYPT };
697 
698 void
699 encrypt_enc_keyid(unsigned char *keyid, int len)
700 {
701 	encrypt_keyid(&ki[1], keyid, len);
702 }
703 
704 void
705 encrypt_dec_keyid(unsigned char *keyid, int len)
706 {
707 	encrypt_keyid(&ki[0], keyid, len);
708 }
709 
710 void
711 encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len)
712 {
713 	Encryptions *ep;
714 	int dir = kp->dir;
715 	int ret = 0;
716 
717 	if (!(ep = (*kp->getcrypt)(*kp->modep))) {
718 		if (len == 0)
719 			return;
720 		kp->keylen = 0;
721 	} else if (len == 0) {
722 		/*
723 		 * Empty option, indicates a failure.
724 		 */
725 		if (kp->keylen == 0)
726 			return;
727 		kp->keylen = 0;
728 		if (ep->keyid)
729 			(void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
730 
731 	} else if ((len != kp->keylen) ||
732 		   (memcmp(keyid, kp->keyid, len) != 0)) {
733 		/*
734 		 * Length or contents are different
735 		 */
736 		kp->keylen = len;
737 		memmove(kp->keyid, keyid, len);
738 		if (ep->keyid)
739 			(void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
740 	} else {
741 		if (ep->keyid)
742 			ret = (*ep->keyid)(dir, kp->keyid, &kp->keylen);
743 		if ((ret == 0) && (dir == DIR_ENCRYPT) && autoencrypt)
744 			encrypt_start_output(*kp->modep);
745 		return;
746 	}
747 
748 	encrypt_send_keyid(dir, kp->keyid, kp->keylen, 0);
749 }
750 
751 void
752 encrypt_send_keyid(int dir, const char *keyid, int keylen, int saveit)
753 {
754 	unsigned char *strp;
755 
756 	str_keyid[3] = (dir == DIR_ENCRYPT)
757 			? ENCRYPT_ENC_KEYID : ENCRYPT_DEC_KEYID;
758 	if (saveit) {
759 		struct key_info *kp = &ki[(dir == DIR_ENCRYPT) ? 0 : 1];
760 		memmove(kp->keyid, keyid, keylen);
761 		kp->keylen = keylen;
762 	}
763 
764 	for (strp = &str_keyid[4]; keylen > 0; --keylen) {
765 		if ((*strp++ = *keyid++) == IAC)
766 			*strp++ = IAC;
767 	}
768 	*strp++ = IAC;
769 	*strp++ = SE;
770 	net_write(str_keyid, strp - str_keyid);
771 	printsub('>', &str_keyid[2], strp - str_keyid - 2);
772 }
773 
774 void
775 encrypt_auto(int on)
776 {
777 	if (on < 0)
778 		autoencrypt ^= 1;
779 	else
780 		autoencrypt = on ? 1 : 0;
781 }
782 
783 void
784 decrypt_auto(int on)
785 {
786 	if (on < 0)
787 		autodecrypt ^= 1;
788 	else
789 		autodecrypt = on ? 1 : 0;
790 }
791 
792 void
793 encrypt_start_output(int type)
794 {
795 	Encryptions *ep;
796 	unsigned char *p;
797 	int i;
798 
799 	if (!(ep = findencryption(type))) {
800 		if (encrypt_debug_mode) {
801 			printf(">>>%s: Can't encrypt with type %s (%d)\r\n",
802 				Name,
803 				ENCTYPE_NAME_OK(type)
804 					? ENCTYPE_NAME(type) : "(unknown)",
805 				type);
806 		}
807 		return;
808 	}
809 	if (ep->start) {
810 		i = (*ep->start)(DIR_ENCRYPT, Server);
811 		if (encrypt_debug_mode) {
812 			printf(">>>%s: Encrypt start: %s (%d) %s\r\n",
813 				Name,
814 				(i < 0) ? "failed" :
815 					"initial negotiation in progress",
816 				i, ENCTYPE_NAME(type));
817 		}
818 		if (i)
819 			return;
820 	}
821 	p = str_start + 3;
822 	*p++ = ENCRYPT_START;
823 	for (i = 0; i < ki[0].keylen; ++i) {
824 		if ((*p++ = ki[0].keyid[i]) == IAC)
825 			*p++ = IAC;
826 	}
827 	*p++ = IAC;
828 	*p++ = SE;
829 	net_write(str_start, p - str_start);
830 	net_encrypt();
831 	printsub('>', &str_start[2], p - &str_start[2]);
832 	/*
833 	 * If we are already encrypting in some mode, then
834 	 * encrypt the ring (which includes our request) in
835 	 * the old mode, mark it all as "clear text" and then
836 	 * switch to the new mode.
837 	 */
838 	encrypt_output = ep->output;
839 	encrypt_mode = type;
840 	if (encrypt_debug_mode)
841 		printf(">>>%s: Started to encrypt output with type %s\r\n",
842 			Name, ENCTYPE_NAME(type));
843 	if (encrypt_verbose)
844 		printf("[ Output is now encrypted with type %s ]\r\n",
845 			ENCTYPE_NAME(type));
846 }
847 
848 void
849 encrypt_send_end(void)
850 {
851 	if (!encrypt_output)
852 		return;
853 
854 	str_end[3] = ENCRYPT_END;
855 	net_write(str_end, sizeof(str_end));
856 	net_encrypt();
857 	printsub('>', &str_end[2], sizeof(str_end) - 2);
858 	/*
859 	 * Encrypt the output buffer now because it will not be done by
860 	 * netflush...
861 	 */
862 	encrypt_output = 0;
863 	if (encrypt_debug_mode)
864 		printf(">>>%s: Output is back to clear text\r\n", Name);
865 	if (encrypt_verbose)
866 		printf("[ Output is now clear text ]\r\n");
867 }
868 
869 void
870 encrypt_send_request_start(void)
871 {
872 	unsigned char *p;
873 	int i;
874 
875 	p = &str_start[3];
876 	*p++ = ENCRYPT_REQSTART;
877 	for (i = 0; i < ki[1].keylen; ++i) {
878 		if ((*p++ = ki[1].keyid[i]) == IAC)
879 			*p++ = IAC;
880 	}
881 	*p++ = IAC;
882 	*p++ = SE;
883 	net_write(str_start, p - str_start);
884 	printsub('>', &str_start[2], p - &str_start[2]);
885 	if (encrypt_debug_mode)
886 		printf(">>>%s: Request input to be encrypted\r\n", Name);
887 }
888 
889 void
890 encrypt_send_request_end(void)
891 {
892 	str_end[3] = ENCRYPT_REQEND;
893 	net_write(str_end, sizeof(str_end));
894 	printsub('>', &str_end[2], sizeof(str_end) - 2);
895 
896 	if (encrypt_debug_mode)
897 		printf(">>>%s: Request input to be clear text\r\n", Name);
898 }
899 
900 void
901 encrypt_wait(void)
902 {
903 	if (encrypt_debug_mode)
904 		printf(">>>%s: in encrypt_wait\r\n", Name);
905 	if (!havesessionkey || !(I_SUPPORT_ENCRYPT & remote_supports_decrypt))
906 		return;
907 	while (autoencrypt && !encrypt_output)
908 		if (telnet_spin())
909 			return;
910 }
911 
912 void
913 encrypt_gen_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
914 {
915 	char tbuf[16], *cp;
916 
917 	cnt -= 2;
918 	data += 2;
919 	buf[buflen-1] = '\0';
920 	buf[buflen-2] = '*';
921 	buflen -= 2;;
922 	for (; cnt > 0; cnt--, data++) {
923 		sprintf(tbuf, " %d", *data);
924 		for (cp = tbuf; *cp && buflen > 0; --buflen)
925 			*buf++ = *cp++;
926 		if (buflen <= 0)
927 			return;
928 	}
929 	*buf = '\0';
930 }
931 
932 void
933 encrypt_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
934 {
935 	Encryptions *ep;
936 	int type = data[1];
937 
938 	for (ep = encryptions; ep->type && ep->type != type; ep++)
939 		;
940 
941 	if (ep->printsub)
942 		(*ep->printsub)(data, cnt, buf, buflen);
943 	else
944 		encrypt_gen_printsub(data, cnt, buf, buflen);
945 }
946 #endif	/* ENCRYPTION */
947