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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #if 0
31 #ifndef lint
32 static const char sccsid[] = "@(#)enc_des.c 8.3 (Berkeley) 5/30/95";
33 #endif /* not lint */
34 #endif
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37
38 #ifdef ENCRYPTION
39 # ifdef AUTHENTICATION
40 #include <arpa/telnet.h>
41 #include <openssl/des.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45
46 #include "encrypt.h"
47 #include "key-proto.h"
48 #include "misc-proto.h"
49
50 extern int encrypt_debug_mode;
51
52 #define CFB 0
53 #define OFB 1
54
55 #define NO_SEND_IV 1
56 #define NO_RECV_IV 2
57 #define NO_KEYID 4
58 #define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID)
59 #define SUCCESS 0
60 #define FAILED -1
61
62
63 struct fb {
64 Block krbdes_key;
65 Schedule krbdes_sched;
66 Block temp_feed;
67 unsigned char fb_feed[64];
68 int need_start;
69 int state[2];
70 int keyid[2];
71 struct stinfo {
72 Block str_output;
73 Block str_feed;
74 Block str_iv;
75 Block str_ikey;
76 Schedule str_sched;
77 int str_index;
78 int str_flagshift;
79 } streams[2];
80 };
81
82 static struct fb fb[2];
83
84 struct keyidlist {
85 const char *keyid;
86 int keyidlen;
87 char *key;
88 int keylen;
89 int flags;
90 } keyidlist [] = {
91 { "\0", 1, 0, 0, 0 }, /* default key of zero */
92 { 0, 0, 0, 0, 0 }
93 };
94
95 #define KEYFLAG_MASK 03
96
97 #define KEYFLAG_NOINIT 00
98 #define KEYFLAG_INIT 01
99 #define KEYFLAG_OK 02
100 #define KEYFLAG_BAD 03
101
102 #define KEYFLAG_SHIFT 2
103
104 #define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2)))
105
106 #define FB64_IV 1
107 #define FB64_IV_OK 2
108 #define FB64_IV_BAD 3
109
110
111 void fb64_stream_iv(Block, struct stinfo *);
112 void fb64_init(struct fb *);
113 static int fb64_start(struct fb *, int, int);
114 int fb64_is(unsigned char *, int, struct fb *);
115 int fb64_reply(unsigned char *, int, struct fb *);
116 static void fb64_session(Session_Key *, int, struct fb *);
117 void fb64_stream_key(Block, struct stinfo *);
118 int fb64_keyid(int, unsigned char *, int *, struct fb *);
119
120 void
cfb64_init(int server __unused)121 cfb64_init(int server __unused)
122 {
123 fb64_init(&fb[CFB]);
124 fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64;
125 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB);
126 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB);
127 }
128
129 void
ofb64_init(int server __unused)130 ofb64_init(int server __unused)
131 {
132 fb64_init(&fb[OFB]);
133 fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64;
134 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB);
135 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB);
136 }
137
138 void
fb64_init(struct fb * fbp)139 fb64_init(struct fb *fbp)
140 {
141 memset((void *)fbp, 0, sizeof(*fbp));
142 fbp->state[0] = fbp->state[1] = FAILED;
143 fbp->fb_feed[0] = IAC;
144 fbp->fb_feed[1] = SB;
145 fbp->fb_feed[2] = TELOPT_ENCRYPT;
146 fbp->fb_feed[3] = ENCRYPT_IS;
147 }
148
149 /*
150 * Returns:
151 * -1: some error. Negotiation is done, encryption not ready.
152 * 0: Successful, initial negotiation all done.
153 * 1: successful, negotiation not done yet.
154 * 2: Not yet. Other things (like getting the key from
155 * Kerberos) have to happen before we can continue.
156 */
157 int
cfb64_start(int dir,int server)158 cfb64_start(int dir, int server)
159 {
160 return(fb64_start(&fb[CFB], dir, server));
161 }
162
163 int
ofb64_start(int dir,int server)164 ofb64_start(int dir, int server)
165 {
166 return(fb64_start(&fb[OFB], dir, server));
167 }
168
169 static int
fb64_start(struct fb * fbp,int dir,int server __unused)170 fb64_start(struct fb *fbp, int dir, int server __unused)
171 {
172 size_t x;
173 unsigned char *p;
174 int state;
175
176 switch (dir) {
177 case DIR_DECRYPT:
178 /*
179 * This is simply a request to have the other side
180 * start output (our input). He will negotiate an
181 * IV so we need not look for it.
182 */
183 state = fbp->state[dir-1];
184 if (state == FAILED)
185 state = IN_PROGRESS;
186 break;
187
188 case DIR_ENCRYPT:
189 state = fbp->state[dir-1];
190 if (state == FAILED)
191 state = IN_PROGRESS;
192 else if ((state & NO_SEND_IV) == 0)
193 break;
194
195 if (!VALIDKEY(fbp->krbdes_key)) {
196 fbp->need_start = 1;
197 break;
198 }
199 state &= ~NO_SEND_IV;
200 state |= NO_RECV_IV;
201 if (encrypt_debug_mode)
202 printf("Creating new feed\r\n");
203 /*
204 * Create a random feed and send it over.
205 */
206 DES_random_key((Block *)fbp->temp_feed);
207 DES_ecb_encrypt((Block *)fbp->temp_feed, (Block *)fbp->temp_feed,
208 &fbp->krbdes_sched, 1);
209 p = fbp->fb_feed + 3;
210 *p++ = ENCRYPT_IS;
211 p++;
212 *p++ = FB64_IV;
213 for (x = 0; x < sizeof(Block); ++x) {
214 if ((*p++ = fbp->temp_feed[x]) == IAC)
215 *p++ = IAC;
216 }
217 *p++ = IAC;
218 *p++ = SE;
219 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
220 net_write(fbp->fb_feed, p - fbp->fb_feed);
221 break;
222 default:
223 return(FAILED);
224 }
225 return(fbp->state[dir-1] = state);
226 }
227
228 /*
229 * Returns:
230 * -1: some error. Negotiation is done, encryption not ready.
231 * 0: Successful, initial negotiation all done.
232 * 1: successful, negotiation not done yet.
233 */
234 int
cfb64_is(unsigned char * data,int cnt)235 cfb64_is(unsigned char *data, int cnt)
236 {
237 return(fb64_is(data, cnt, &fb[CFB]));
238 }
239
240 int
ofb64_is(unsigned char * data,int cnt)241 ofb64_is(unsigned char *data, int cnt)
242 {
243 return(fb64_is(data, cnt, &fb[OFB]));
244 }
245
246 int
fb64_is(unsigned char * data,int cnt,struct fb * fbp)247 fb64_is(unsigned char *data, int cnt, struct fb *fbp)
248 {
249 unsigned char *p;
250 int state = fbp->state[DIR_DECRYPT-1];
251
252 if (cnt-- < 1)
253 goto failure;
254
255 switch (*data++) {
256 case FB64_IV:
257 if (cnt != sizeof(Block)) {
258 if (encrypt_debug_mode)
259 printf("CFB64: initial vector failed on size\r\n");
260 state = FAILED;
261 goto failure;
262 }
263
264 if (encrypt_debug_mode)
265 printf("CFB64: initial vector received\r\n");
266
267 if (encrypt_debug_mode)
268 printf("Initializing Decrypt stream\r\n");
269
270 fb64_stream_iv((void *)data, &fbp->streams[DIR_DECRYPT-1]);
271
272 p = fbp->fb_feed + 3;
273 *p++ = ENCRYPT_REPLY;
274 p++;
275 *p++ = FB64_IV_OK;
276 *p++ = IAC;
277 *p++ = SE;
278 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
279 net_write(fbp->fb_feed, p - fbp->fb_feed);
280
281 state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS;
282 break;
283
284 default:
285 if (encrypt_debug_mode) {
286 printf("Unknown option type: %d\r\n", *(data-1));
287 printd(data, cnt);
288 printf("\r\n");
289 }
290 /* FALL THROUGH */
291 failure:
292 /*
293 * We failed. Send an FB64_IV_BAD option
294 * to the other side so it will know that
295 * things failed.
296 */
297 p = fbp->fb_feed + 3;
298 *p++ = ENCRYPT_REPLY;
299 p++;
300 *p++ = FB64_IV_BAD;
301 *p++ = IAC;
302 *p++ = SE;
303 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
304 net_write(fbp->fb_feed, p - fbp->fb_feed);
305
306 break;
307 }
308 return(fbp->state[DIR_DECRYPT-1] = state);
309 }
310
311 /*
312 * Returns:
313 * -1: some error. Negotiation is done, encryption not ready.
314 * 0: Successful, initial negotiation all done.
315 * 1: successful, negotiation not done yet.
316 */
317 int
cfb64_reply(unsigned char * data,int cnt)318 cfb64_reply(unsigned char *data, int cnt)
319 {
320 return(fb64_reply(data, cnt, &fb[CFB]));
321 }
322
323 int
ofb64_reply(unsigned char * data,int cnt)324 ofb64_reply(unsigned char *data, int cnt)
325 {
326 return(fb64_reply(data, cnt, &fb[OFB]));
327 }
328
329 int
fb64_reply(unsigned char * data,int cnt,struct fb * fbp)330 fb64_reply(unsigned char *data, int cnt, struct fb *fbp)
331 {
332 int state = fbp->state[DIR_ENCRYPT-1];
333
334 if (cnt-- < 1)
335 goto failure;
336
337 switch (*data++) {
338 case FB64_IV_OK:
339 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]);
340 if (state == FAILED)
341 state = IN_PROGRESS;
342 state &= ~NO_RECV_IV;
343 encrypt_send_keyid(DIR_ENCRYPT, "\0", 1, 1);
344 break;
345
346 case FB64_IV_BAD:
347 memset(fbp->temp_feed, 0, sizeof(Block));
348 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]);
349 state = FAILED;
350 break;
351
352 default:
353 if (encrypt_debug_mode) {
354 printf("Unknown option type: %d\r\n", data[-1]);
355 printd(data, cnt);
356 printf("\r\n");
357 }
358 /* FALL THROUGH */
359 failure:
360 state = FAILED;
361 break;
362 }
363 return(fbp->state[DIR_ENCRYPT-1] = state);
364 }
365
366 void
cfb64_session(Session_Key * key,int server)367 cfb64_session(Session_Key *key, int server)
368 {
369 fb64_session(key, server, &fb[CFB]);
370 }
371
372 void
ofb64_session(Session_Key * key,int server)373 ofb64_session(Session_Key *key, int server)
374 {
375 fb64_session(key, server, &fb[OFB]);
376 }
377
378 static void
fb64_session(Session_Key * key,int server,struct fb * fbp)379 fb64_session(Session_Key *key, int server, struct fb *fbp)
380 {
381 if (!key || key->type != SK_DES) {
382 if (encrypt_debug_mode)
383 printf("Can't set krbdes's session key (%d != %d)\r\n",
384 key ? key->type : -1, SK_DES);
385 return;
386 }
387 memmove((void *)fbp->krbdes_key, (void *)key->data, sizeof(Block));
388
389 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]);
390 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]);
391
392 DES_key_sched((Block *)fbp->krbdes_key, &fbp->krbdes_sched);
393 /*
394 * Now look to see if krbdes_start() was was waiting for
395 * the key to show up. If so, go ahead an call it now
396 * that we have the key.
397 */
398 if (fbp->need_start) {
399 fbp->need_start = 0;
400 fb64_start(fbp, DIR_ENCRYPT, server);
401 }
402 }
403
404 /*
405 * We only accept a keyid of 0. If we get a keyid of
406 * 0, then mark the state as SUCCESS.
407 */
408 int
cfb64_keyid(int dir,unsigned char * kp,int * lenp)409 cfb64_keyid(int dir, unsigned char *kp, int *lenp)
410 {
411 return(fb64_keyid(dir, kp, lenp, &fb[CFB]));
412 }
413
414 int
ofb64_keyid(int dir,unsigned char * kp,int * lenp)415 ofb64_keyid(int dir, unsigned char *kp, int *lenp)
416 {
417 return(fb64_keyid(dir, kp, lenp, &fb[OFB]));
418 }
419
420 int
fb64_keyid(int dir,unsigned char * kp,int * lenp,struct fb * fbp)421 fb64_keyid(int dir, unsigned char *kp, int *lenp, struct fb *fbp)
422 {
423 int state = fbp->state[dir-1];
424
425 if (*lenp != 1 || (*kp != '\0')) {
426 *lenp = 0;
427 return(state);
428 }
429
430 if (state == FAILED)
431 state = IN_PROGRESS;
432
433 state &= ~NO_KEYID;
434
435 return(fbp->state[dir-1] = state);
436 }
437
438 void
fb64_printsub(unsigned char * data,int cnt,unsigned char * buf,int buflen,const char * type)439 fb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen, const char *type)
440 {
441 char lbuf[32];
442 int i;
443 char *cp;
444
445 buf[buflen-1] = '\0'; /* make sure it's NULL terminated */
446 buflen -= 1;
447
448 switch(data[2]) {
449 case FB64_IV:
450 sprintf(lbuf, "%s_IV", type);
451 cp = lbuf;
452 goto common;
453
454 case FB64_IV_OK:
455 sprintf(lbuf, "%s_IV_OK", type);
456 cp = lbuf;
457 goto common;
458
459 case FB64_IV_BAD:
460 sprintf(lbuf, "%s_IV_BAD", type);
461 cp = lbuf;
462 goto common;
463
464 default:
465 sprintf(lbuf, " %d (unknown)", data[2]);
466 cp = lbuf;
467 common:
468 for (; (buflen > 0) && (*buf = *cp++); buf++)
469 buflen--;
470 for (i = 3; i < cnt; i++) {
471 sprintf(lbuf, " %d", data[i]);
472 for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++)
473 buflen--;
474 }
475 break;
476 }
477 }
478
479 void
cfb64_printsub(unsigned char * data,int cnt,unsigned char * buf,int buflen)480 cfb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
481 {
482 fb64_printsub(data, cnt, buf, buflen, "CFB64");
483 }
484
485 void
ofb64_printsub(unsigned char * data,int cnt,unsigned char * buf,int buflen)486 ofb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
487 {
488 fb64_printsub(data, cnt, buf, buflen, "OFB64");
489 }
490
491 void
fb64_stream_iv(Block seed,struct stinfo * stp)492 fb64_stream_iv(Block seed, struct stinfo *stp)
493 {
494
495 memmove((void *)stp->str_iv, (void *)seed, sizeof(Block));
496 memmove((void *)stp->str_output, (void *)seed, sizeof(Block));
497
498 DES_key_sched((Block *)stp->str_ikey, &stp->str_sched);
499
500 stp->str_index = sizeof(Block);
501 }
502
503 void
fb64_stream_key(Block key,struct stinfo * stp)504 fb64_stream_key(Block key, struct stinfo *stp)
505 {
506 memmove((void *)stp->str_ikey, (void *)key, sizeof(Block));
507 DES_key_sched((Block *)key, &stp->str_sched);
508
509 memmove((void *)stp->str_output, (void *)stp->str_iv, sizeof(Block));
510
511 stp->str_index = sizeof(Block);
512 }
513
514 /*
515 * DES 64 bit Cipher Feedback
516 *
517 * key --->+-----+
518 * +->| DES |--+
519 * | +-----+ |
520 * | v
521 * INPUT --(--------->(+)+---> DATA
522 * | |
523 * +-------------+
524 *
525 *
526 * Given:
527 * iV: Initial vector, 64 bits (8 bytes) long.
528 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt).
529 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output.
530 *
531 * V0 = DES(iV, key)
532 * On = Dn ^ Vn
533 * V(n+1) = DES(On, key)
534 */
535
536 void
cfb64_encrypt(unsigned char * s,int c)537 cfb64_encrypt(unsigned char *s, int c)
538 {
539 struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1];
540 int idx;
541
542 idx = stp->str_index;
543 while (c-- > 0) {
544 if (idx == sizeof(Block)) {
545 Block b;
546 DES_ecb_encrypt((Block *)stp->str_output, (Block *)b, &stp->str_sched, 1);
547 memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
548 idx = 0;
549 }
550
551 /* On encryption, we store (feed ^ data) which is cypher */
552 *s = stp->str_output[idx] = (stp->str_feed[idx] ^ *s);
553 s++;
554 idx++;
555 }
556 stp->str_index = idx;
557 }
558
559 int
cfb64_decrypt(int data)560 cfb64_decrypt(int data)
561 {
562 struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1];
563 int idx;
564
565 if (data == -1) {
566 /*
567 * Back up one byte. It is assumed that we will
568 * never back up more than one byte. If we do, this
569 * may or may not work.
570 */
571 if (stp->str_index)
572 --stp->str_index;
573 return(0);
574 }
575
576 idx = stp->str_index++;
577 if (idx == sizeof(Block)) {
578 Block b;
579 DES_ecb_encrypt((Block *)stp->str_output, (Block *)b, &stp->str_sched, 1);
580 memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
581 stp->str_index = 1; /* Next time will be 1 */
582 idx = 0; /* But now use 0 */
583 }
584
585 /* On decryption we store (data) which is cypher. */
586 stp->str_output[idx] = data;
587 return(data ^ stp->str_feed[idx]);
588 }
589
590 /*
591 * DES 64 bit Output Feedback
592 *
593 * key --->+-----+
594 * +->| DES |--+
595 * | +-----+ |
596 * +-----------+
597 * v
598 * INPUT -------->(+) ----> DATA
599 *
600 * Given:
601 * iV: Initial vector, 64 bits (8 bytes) long.
602 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt).
603 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output.
604 *
605 * V0 = DES(iV, key)
606 * V(n+1) = DES(Vn, key)
607 * On = Dn ^ Vn
608 */
609 void
ofb64_encrypt(unsigned char * s,int c)610 ofb64_encrypt(unsigned char *s, int c)
611 {
612 struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1];
613 int idx;
614
615 idx = stp->str_index;
616 while (c-- > 0) {
617 if (idx == sizeof(Block)) {
618 Block b;
619 DES_ecb_encrypt((Block *)stp->str_feed, (Block *)b, &stp->str_sched, 1);
620 memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
621 idx = 0;
622 }
623 *s++ ^= stp->str_feed[idx];
624 idx++;
625 }
626 stp->str_index = idx;
627 }
628
629 int
ofb64_decrypt(int data)630 ofb64_decrypt(int data)
631 {
632 struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1];
633 int idx;
634
635 if (data == -1) {
636 /*
637 * Back up one byte. It is assumed that we will
638 * never back up more than one byte. If we do, this
639 * may or may not work.
640 */
641 if (stp->str_index)
642 --stp->str_index;
643 return(0);
644 }
645
646 idx = stp->str_index++;
647 if (idx == sizeof(Block)) {
648 Block b;
649 DES_ecb_encrypt((Block *)stp->str_feed, (Block *)b, &stp->str_sched, 1);
650 memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
651 stp->str_index = 1; /* Next time will be 1 */
652 idx = 0; /* But now use 0 */
653 }
654
655 return(data ^ stp->str_feed[idx]);
656 }
657 # endif /* AUTHENTICATION */
658 #endif /* ENCRYPTION */
659