enc_des.c revision 29088 
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
34#ifndef lint
35static char sccsid[] = "@(#)enc_des.c	8.3 (Berkeley) 5/30/95";
36#endif /* not lint */
37
38#ifdef	ENCRYPTION
39# ifdef	AUTHENTICATION
40#  ifdef DES_ENCRYPTION
41#include <arpa/telnet.h>
42#include <stdio.h>
43#ifdef	__STDC__
44#include <stdlib.h>
45#endif
46
47#include "encrypt.h"
48#include "key-proto.h"
49#include "misc-proto.h"
50
51extern encrypt_debug_mode;
52
53#define	CFB	0
54#define	OFB	1
55
56#define	NO_SEND_IV	1
57#define	NO_RECV_IV	2
58#define	NO_KEYID	4
59#define	IN_PROGRESS	(NO_SEND_IV|NO_RECV_IV|NO_KEYID)
60#define	SUCCESS		0
61#define	FAILED		-1
62
63
64struct fb {
65	Block krbdes_key;
66	Schedule krbdes_sched;
67	Block temp_feed;
68	unsigned char fb_feed[64];
69	int need_start;
70	int state[2];
71	int keyid[2];
72	int once;
73	struct stinfo {
74		Block		str_output;
75		Block		str_feed;
76		Block		str_iv;
77		Block		str_ikey;
78		Schedule	str_sched;
79		int		str_index;
80		int		str_flagshift;
81	} streams[2];
82};
83
84static struct fb fb[2];
85
86struct keyidlist {
87	char	*keyid;
88	int	keyidlen;
89	char	*key;
90	int	keylen;
91	int	flags;
92} keyidlist [] = {
93	{ "\0", 1, 0, 0, 0 },		/* default key of zero */
94	{ 0, 0, 0, 0, 0 }
95};
96
97#define	KEYFLAG_MASK	03
98
99#define	KEYFLAG_NOINIT	00
100#define	KEYFLAG_INIT	01
101#define	KEYFLAG_OK	02
102#define	KEYFLAG_BAD	03
103
104#define	KEYFLAG_SHIFT	2
105
106#define	SHIFT_VAL(a,b)	(KEYFLAG_SHIFT*((a)+((b)*2)))
107
108#define	FB64_IV		1
109#define	FB64_IV_OK	2
110#define	FB64_IV_BAD	3
111
112
113void fb64_stream_iv P((Block, struct stinfo *));
114void fb64_init P((struct fb *));
115static int fb64_start P((struct fb *, int, int));
116int fb64_is P((unsigned char *, int, struct fb *));
117int fb64_reply P((unsigned char *, int, struct fb *));
118static void fb64_session P((Session_Key *, int, struct fb *));
119void fb64_stream_key P((Block, struct stinfo *));
120int fb64_keyid P((int, unsigned char *, int *, struct fb *));
121
122	void
123cfb64_init(server)
124	int server;
125{
126	fb64_init(&fb[CFB]);
127	fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64;
128	fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB);
129	fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB);
130}
131
132	void
133ofb64_init(server)
134	int server;
135{
136	fb64_init(&fb[OFB]);
137	fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64;
138	fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB);
139	fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB);
140}
141
142	void
143fb64_init(fbp)
144	register struct fb *fbp;
145{
146	memset((void *)fbp, 0, sizeof(*fbp));
147	fbp->state[0] = fbp->state[1] = FAILED;
148	fbp->fb_feed[0] = IAC;
149	fbp->fb_feed[1] = SB;
150	fbp->fb_feed[2] = TELOPT_ENCRYPT;
151	fbp->fb_feed[3] = ENCRYPT_IS;
152}
153
154/*
155 * Returns:
156 *	-1: some error.  Negotiation is done, encryption not ready.
157 *	 0: Successful, initial negotiation all done.
158 *	 1: successful, negotiation not done yet.
159 *	 2: Not yet.  Other things (like getting the key from
160 *	    Kerberos) have to happen before we can continue.
161 */
162	int
163cfb64_start(dir, server)
164	int dir;
165	int server;
166{
167	return(fb64_start(&fb[CFB], dir, server));
168}
169	int
170ofb64_start(dir, server)
171	int dir;
172	int server;
173{
174	return(fb64_start(&fb[OFB], dir, server));
175}
176
177	static int
178fb64_start(fbp, dir, server)
179	struct fb *fbp;
180	int dir;
181	int server;
182{
183	Block b;
184	int x;
185	unsigned char *p;
186	register int state;
187
188	switch (dir) {
189	case DIR_DECRYPT:
190		/*
191		 * This is simply a request to have the other side
192		 * start output (our input).  He will negotiate an
193		 * IV so we need not look for it.
194		 */
195		state = fbp->state[dir-1];
196		if (state == FAILED)
197			state = IN_PROGRESS;
198		break;
199
200	case DIR_ENCRYPT:
201		state = fbp->state[dir-1];
202		if (state == FAILED)
203			state = IN_PROGRESS;
204		else if ((state & NO_SEND_IV) == 0)
205			break;
206
207		if (!VALIDKEY(fbp->krbdes_key)) {
208			fbp->need_start = 1;
209			break;
210		}
211		state &= ~NO_SEND_IV;
212		state |= NO_RECV_IV;
213		if (encrypt_debug_mode)
214			printf("Creating new feed\r\n");
215		/*
216		 * Create a random feed and send it over.
217		 */
218		des_new_random_key(fbp->temp_feed);
219		des_ecb_encrypt(fbp->temp_feed, fbp->temp_feed,
220				fbp->krbdes_sched, 1);
221		p = fbp->fb_feed + 3;
222		*p++ = ENCRYPT_IS;
223		p++;
224		*p++ = FB64_IV;
225		for (x = 0; x < sizeof(Block); ++x) {
226			if ((*p++ = fbp->temp_feed[x]) == IAC)
227				*p++ = IAC;
228		}
229		*p++ = IAC;
230		*p++ = SE;
231		printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
232		net_write(fbp->fb_feed, p - fbp->fb_feed);
233		break;
234	default:
235		return(FAILED);
236	}
237	return(fbp->state[dir-1] = state);
238}
239
240/*
241 * Returns:
242 *	-1: some error.  Negotiation is done, encryption not ready.
243 *	 0: Successful, initial negotiation all done.
244 *	 1: successful, negotiation not done yet.
245 */
246	int
247cfb64_is(data, cnt)
248	unsigned char *data;
249	int cnt;
250{
251	return(fb64_is(data, cnt, &fb[CFB]));
252}
253	int
254ofb64_is(data, cnt)
255	unsigned char *data;
256	int cnt;
257{
258	return(fb64_is(data, cnt, &fb[OFB]));
259}
260
261	int
262fb64_is(data, cnt, fbp)
263	unsigned char *data;
264	int cnt;
265	struct fb *fbp;
266{
267	int x;
268	unsigned char *p;
269	Block b;
270	register int state = fbp->state[DIR_DECRYPT-1];
271
272	if (cnt-- < 1)
273		goto failure;
274
275	switch (*data++) {
276	case FB64_IV:
277		if (cnt != sizeof(Block)) {
278			if (encrypt_debug_mode)
279				printf("CFB64: initial vector failed on size\r\n");
280			state = FAILED;
281			goto failure;
282		}
283
284		if (encrypt_debug_mode)
285			printf("CFB64: initial vector received\r\n");
286
287		if (encrypt_debug_mode)
288			printf("Initializing Decrypt stream\r\n");
289
290		fb64_stream_iv((void *)data, &fbp->streams[DIR_DECRYPT-1]);
291
292		p = fbp->fb_feed + 3;
293		*p++ = ENCRYPT_REPLY;
294		p++;
295		*p++ = FB64_IV_OK;
296		*p++ = IAC;
297		*p++ = SE;
298		printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
299		net_write(fbp->fb_feed, p - fbp->fb_feed);
300
301		state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS;
302		break;
303
304	default:
305		if (encrypt_debug_mode) {
306			printf("Unknown option type: %d\r\n", *(data-1));
307			printd(data, cnt);
308			printf("\r\n");
309		}
310		/* FALL THROUGH */
311	failure:
312		/*
313		 * We failed.  Send an FB64_IV_BAD option
314		 * to the other side so it will know that
315		 * things failed.
316		 */
317		p = fbp->fb_feed + 3;
318		*p++ = ENCRYPT_REPLY;
319		p++;
320		*p++ = FB64_IV_BAD;
321		*p++ = IAC;
322		*p++ = SE;
323		printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
324		net_write(fbp->fb_feed, p - fbp->fb_feed);
325
326		break;
327	}
328	return(fbp->state[DIR_DECRYPT-1] = state);
329}
330
331/*
332 * Returns:
333 *	-1: some error.  Negotiation is done, encryption not ready.
334 *	 0: Successful, initial negotiation all done.
335 *	 1: successful, negotiation not done yet.
336 */
337	int
338cfb64_reply(data, cnt)
339	unsigned char *data;
340	int cnt;
341{
342	return(fb64_reply(data, cnt, &fb[CFB]));
343}
344	int
345ofb64_reply(data, cnt)
346	unsigned char *data;
347	int cnt;
348{
349	return(fb64_reply(data, cnt, &fb[OFB]));
350}
351
352
353	int
354fb64_reply(data, cnt, fbp)
355	unsigned char *data;
356	int cnt;
357	struct fb *fbp;
358{
359	int x;
360	unsigned char *p;
361	Block b;
362	register int state = fbp->state[DIR_ENCRYPT-1];
363
364	if (cnt-- < 1)
365		goto failure;
366
367	switch (*data++) {
368	case FB64_IV_OK:
369		fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]);
370		if (state == FAILED)
371			state = IN_PROGRESS;
372		state &= ~NO_RECV_IV;
373		encrypt_send_keyid(DIR_ENCRYPT, (unsigned char *)"\0", 1, 1);
374		break;
375
376	case FB64_IV_BAD:
377		memset(fbp->temp_feed, 0, sizeof(Block));
378		fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]);
379		state = FAILED;
380		break;
381
382	default:
383		if (encrypt_debug_mode) {
384			printf("Unknown option type: %d\r\n", data[-1]);
385			printd(data, cnt);
386			printf("\r\n");
387		}
388		/* FALL THROUGH */
389	failure:
390		state = FAILED;
391		break;
392	}
393	return(fbp->state[DIR_ENCRYPT-1] = state);
394}
395
396	void
397cfb64_session(key, server)
398	Session_Key *key;
399	int server;
400{
401	fb64_session(key, server, &fb[CFB]);
402}
403
404	void
405ofb64_session(key, server)
406	Session_Key *key;
407	int server;
408{
409	fb64_session(key, server, &fb[OFB]);
410}
411
412	static void
413fb64_session(key, server, fbp)
414	Session_Key *key;
415	int server;
416	struct fb *fbp;
417{
418
419	if (!key || key->type != SK_DES) {
420		if (encrypt_debug_mode)
421			printf("Can't set krbdes's session key (%d != %d)\r\n",
422				key ? key->type : -1, SK_DES);
423		return;
424	}
425	memmove((void *)fbp->krbdes_key, (void *)key->data, sizeof(Block));
426
427	fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]);
428	fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]);
429
430	if (fbp->once == 0) {
431		des_set_random_generator_seed(fbp->krbdes_key);
432		fbp->once = 1;
433	}
434	des_key_sched(fbp->krbdes_key, fbp->krbdes_sched);
435	/*
436	 * Now look to see if krbdes_start() was was waiting for
437	 * the key to show up.  If so, go ahead an call it now
438	 * that we have the key.
439	 */
440	if (fbp->need_start) {
441		fbp->need_start = 0;
442		fb64_start(fbp, DIR_ENCRYPT, server);
443	}
444}
445
446/*
447 * We only accept a keyid of 0.  If we get a keyid of
448 * 0, then mark the state as SUCCESS.
449 */
450	int
451cfb64_keyid(dir, kp, lenp)
452	int dir, *lenp;
453	unsigned char *kp;
454{
455	return(fb64_keyid(dir, kp, lenp, &fb[CFB]));
456}
457
458	int
459ofb64_keyid(dir, kp, lenp)
460	int dir, *lenp;
461	unsigned char *kp;
462{
463	return(fb64_keyid(dir, kp, lenp, &fb[OFB]));
464}
465
466	int
467fb64_keyid(dir, kp, lenp, fbp)
468	int dir, *lenp;
469	unsigned char *kp;
470	struct fb *fbp;
471{
472	register int state = fbp->state[dir-1];
473
474	if (*lenp != 1 || (*kp != '\0')) {
475		*lenp = 0;
476		return(state);
477	}
478
479	if (state == FAILED)
480		state = IN_PROGRESS;
481
482	state &= ~NO_KEYID;
483
484	return(fbp->state[dir-1] = state);
485}
486
487	void
488fb64_printsub(data, cnt, buf, buflen, type)
489	unsigned char *data, *buf, *type;
490	int cnt, buflen;
491{
492	char lbuf[32];
493	register int i;
494	char *cp;
495
496	buf[buflen-1] = '\0';		/* make sure it's NULL terminated */
497	buflen -= 1;
498
499	switch(data[2]) {
500	case FB64_IV:
501		sprintf(lbuf, "%s_IV", type);
502		cp = lbuf;
503		goto common;
504
505	case FB64_IV_OK:
506		sprintf(lbuf, "%s_IV_OK", type);
507		cp = lbuf;
508		goto common;
509
510	case FB64_IV_BAD:
511		sprintf(lbuf, "%s_IV_BAD", type);
512		cp = lbuf;
513		goto common;
514
515	default:
516		sprintf(lbuf, " %d (unknown)", data[2]);
517		cp = lbuf;
518	common:
519		for (; (buflen > 0) && (*buf = *cp++); buf++)
520			buflen--;
521		for (i = 3; i < cnt; i++) {
522			sprintf(lbuf, " %d", data[i]);
523			for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++)
524				buflen--;
525		}
526		break;
527	}
528}
529
530	void
531cfb64_printsub(data, cnt, buf, buflen)
532	unsigned char *data, *buf;
533	int cnt, buflen;
534{
535	fb64_printsub(data, cnt, buf, buflen, "CFB64");
536}
537
538	void
539ofb64_printsub(data, cnt, buf, buflen)
540	unsigned char *data, *buf;
541	int cnt, buflen;
542{
543	fb64_printsub(data, cnt, buf, buflen, "OFB64");
544}
545
546	void
547fb64_stream_iv(seed, stp)
548	Block seed;
549	register struct stinfo *stp;
550{
551
552	memmove((void *)stp->str_iv, (void *)seed, sizeof(Block));
553	memmove((void *)stp->str_output, (void *)seed, sizeof(Block));
554
555	des_key_sched(stp->str_ikey, stp->str_sched);
556
557	stp->str_index = sizeof(Block);
558}
559
560	void
561fb64_stream_key(key, stp)
562	Block key;
563	register struct stinfo *stp;
564{
565	memmove((void *)stp->str_ikey, (void *)key, sizeof(Block));
566	des_key_sched(key, stp->str_sched);
567
568	memmove((void *)stp->str_output, (void *)stp->str_iv, sizeof(Block));
569
570	stp->str_index = sizeof(Block);
571}
572
573/*
574 * DES 64 bit Cipher Feedback
575 *
576 *     key --->+-----+
577 *          +->| DES |--+
578 *          |  +-----+  |
579 *	    |           v
580 *  INPUT --(--------->(+)+---> DATA
581 *          |             |
582 *	    +-------------+
583 *
584 *
585 * Given:
586 *	iV: Initial vector, 64 bits (8 bytes) long.
587 *	Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt).
588 *	On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output.
589 *
590 *	V0 = DES(iV, key)
591 *	On = Dn ^ Vn
592 *	V(n+1) = DES(On, key)
593 */
594
595	void
596cfb64_encrypt(s, c)
597	register unsigned char *s;
598	int c;
599{
600	register struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1];
601	register int index;
602
603	index = stp->str_index;
604	while (c-- > 0) {
605		if (index == sizeof(Block)) {
606			Block b;
607			des_ecb_encrypt(stp->str_output, b, stp->str_sched, 1);
608			memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
609			index = 0;
610		}
611
612		/* On encryption, we store (feed ^ data) which is cypher */
613		*s = stp->str_output[index] = (stp->str_feed[index] ^ *s);
614		s++;
615		index++;
616	}
617	stp->str_index = index;
618}
619
620	int
621cfb64_decrypt(data)
622	int data;
623{
624	register struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1];
625	int index;
626
627	if (data == -1) {
628		/*
629		 * Back up one byte.  It is assumed that we will
630		 * never back up more than one byte.  If we do, this
631		 * may or may not work.
632		 */
633		if (stp->str_index)
634			--stp->str_index;
635		return(0);
636	}
637
638	index = stp->str_index++;
639	if (index == sizeof(Block)) {
640		Block b;
641		des_ecb_encrypt(stp->str_output, b, stp->str_sched, 1);
642		memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
643		stp->str_index = 1;	/* Next time will be 1 */
644		index = 0;		/* But now use 0 */
645	}
646
647	/* On decryption we store (data) which is cypher. */
648	stp->str_output[index] = data;
649	return(data ^ stp->str_feed[index]);
650}
651
652/*
653 * DES 64 bit Output Feedback
654 *
655 * key --->+-----+
656 *	+->| DES |--+
657 *	|  +-----+  |
658 *	+-----------+
659 *	            v
660 *  INPUT -------->(+) ----> DATA
661 *
662 * Given:
663 *	iV: Initial vector, 64 bits (8 bytes) long.
664 *	Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt).
665 *	On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output.
666 *
667 *	V0 = DES(iV, key)
668 *	V(n+1) = DES(Vn, key)
669 *	On = Dn ^ Vn
670 */
671	void
672ofb64_encrypt(s, c)
673	register unsigned char *s;
674	int c;
675{
676	register struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1];
677	register int index;
678
679	index = stp->str_index;
680	while (c-- > 0) {
681		if (index == sizeof(Block)) {
682			Block b;
683			des_ecb_encrypt(stp->str_feed, b, stp->str_sched, 1);
684			memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
685			index = 0;
686		}
687		*s++ ^= stp->str_feed[index];
688		index++;
689	}
690	stp->str_index = index;
691}
692
693	int
694ofb64_decrypt(data)
695	int data;
696{
697	register struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1];
698	int index;
699
700	if (data == -1) {
701		/*
702		 * Back up one byte.  It is assumed that we will
703		 * never back up more than one byte.  If we do, this
704		 * may or may not work.
705		 */
706		if (stp->str_index)
707			--stp->str_index;
708		return(0);
709	}
710
711	index = stp->str_index++;
712	if (index == sizeof(Block)) {
713		Block b;
714		des_ecb_encrypt(stp->str_feed, b, stp->str_sched, 1);
715		memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
716		stp->str_index = 1;	/* Next time will be 1 */
717		index = 0;		/* But now use 0 */
718	}
719
720	return(data ^ stp->str_feed[index]);
721}
722#  endif /* DES_ENCRYPTION */
723# endif	/* AUTHENTICATION */
724#endif	/* ENCRYPTION */
725