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 * $FreeBSD: src/crypto/telnet/libtelnet/enc_des.c,v 1.3.2.1 2002/04/13 10:59:07 markm Exp $ 34 */ 35 36#include <sys/cdefs.h> 37 38#ifdef __FBSDID 39__FBSDID("$FreeBSD: src/crypto/telnet/libtelnet/enc_des.c,v 1.3.2.1 2002/04/13 10:59:07 markm Exp $"); 40#endif 41 42#ifndef __unused 43#define __unused __attribute__((__unused__)) 44#endif 45 46#ifndef lint 47static const char sccsid[] = "@(#)enc_des.c 8.3 (Berkeley) 5/30/95"; 48#endif /* not lint */ 49 50#ifdef ENCRYPTION 51# ifdef AUTHENTICATION 52#include <arpa/telnet.h> 53#include <des.h> 54#include <stdio.h> 55#include <stdlib.h> 56#include <string.h> 57 58#include "encrypt.h" 59#include "key-proto.h" 60#include "misc-proto.h" 61 62extern int encrypt_debug_mode; 63 64#define CFB 0 65#define OFB 1 66 67#define NO_SEND_IV 1 68#define NO_RECV_IV 2 69#define NO_KEYID 4 70#define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID) 71#define SUCCESS 0 72#define FAILED -1 73 74 75struct fb { 76 Block krbdes_key; 77 Schedule krbdes_sched; 78 Block temp_feed; 79 unsigned char fb_feed[64]; 80 int need_start; 81 int state[2]; 82 int keyid[2]; 83 int once; 84 struct stinfo { 85 Block str_output; 86 Block str_feed; 87 Block str_iv; 88 Block str_ikey; 89 Schedule str_sched; 90 int str_index; 91 int str_flagshift; 92 } streams[2]; 93}; 94 95static struct fb fb[2]; 96 97struct keyidlist { 98 const char *keyid; 99 int keyidlen; 100 char *key; 101 int keylen; 102 int flags; 103} keyidlist [] = { 104 { "\0", 1, 0, 0, 0 }, /* default key of zero */ 105 { 0, 0, 0, 0, 0 } 106}; 107 108#define KEYFLAG_MASK 03 109 110#define KEYFLAG_NOINIT 00 111#define KEYFLAG_INIT 01 112#define KEYFLAG_OK 02 113#define KEYFLAG_BAD 03 114 115#define KEYFLAG_SHIFT 2 116 117#define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2))) 118 119#define FB64_IV 1 120#define FB64_IV_OK 2 121#define FB64_IV_BAD 3 122 123 124void fb64_stream_iv(Block, struct stinfo *); 125void fb64_init(struct fb *); 126static int fb64_start(struct fb *, int, int); 127int fb64_is(unsigned char *, int, struct fb *); 128int fb64_reply(unsigned char *, int, struct fb *); 129static void fb64_session(Session_Key *, int, struct fb *); 130void fb64_stream_key(Block, struct stinfo *); 131int fb64_keyid(int, unsigned char *, int *, struct fb *); 132 133void 134cfb64_init(int server __unused) 135{ 136 fb64_init(&fb[CFB]); 137 fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64; 138 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB); 139 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB); 140} 141 142void 143ofb64_init(int server __unused) 144{ 145 fb64_init(&fb[OFB]); 146 fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64; 147 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB); 148 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB); 149} 150 151void 152fb64_init(struct fb *fbp) 153{ 154 memset((void *)fbp, 0, sizeof(*fbp)); 155 fbp->state[0] = fbp->state[1] = FAILED; 156 fbp->fb_feed[0] = IAC; 157 fbp->fb_feed[1] = SB; 158 fbp->fb_feed[2] = TELOPT_ENCRYPT; 159 fbp->fb_feed[3] = ENCRYPT_IS; 160} 161 162/* 163 * Returns: 164 * -1: some error. Negotiation is done, encryption not ready. 165 * 0: Successful, initial negotiation all done. 166 * 1: successful, negotiation not done yet. 167 * 2: Not yet. Other things (like getting the key from 168 * Kerberos) have to happen before we can continue. 169 */ 170int 171cfb64_start(int dir, int server) 172{ 173 return(fb64_start(&fb[CFB], dir, server)); 174} 175 176int 177ofb64_start(int dir, int server) 178{ 179 return(fb64_start(&fb[OFB], dir, server)); 180} 181 182static int 183fb64_start(struct fb *fbp, int dir, int server __unused) 184{ 185 size_t x; 186 unsigned char *p; 187 int state; 188 189 switch (dir) { 190 case DIR_DECRYPT: 191 /* 192 * This is simply a request to have the other side 193 * start output (our input). He will negotiate an 194 * IV so we need not look for it. 195 */ 196 state = fbp->state[dir-1]; 197 if (state == FAILED) 198 state = IN_PROGRESS; 199 break; 200 201 case DIR_ENCRYPT: 202 state = fbp->state[dir-1]; 203 if (state == FAILED) 204 state = IN_PROGRESS; 205 else if ((state & NO_SEND_IV) == 0) 206 break; 207 208 if (!VALIDKEY(fbp->krbdes_key)) { 209 fbp->need_start = 1; 210 break; 211 } 212 state &= ~NO_SEND_IV; 213 state |= NO_RECV_IV; 214 if (encrypt_debug_mode) 215 printf("Creating new feed\r\n"); 216 /* 217 * Create a random feed and send it over. 218 */ 219 des_new_random_key(fbp->temp_feed); 220 des_ecb_encrypt((Block *)fbp->temp_feed, (Block *)fbp->temp_feed, 221 fbp->krbdes_sched, 1); 222 p = fbp->fb_feed + 3; 223 *p++ = ENCRYPT_IS; 224 p++; 225 *p++ = FB64_IV; 226 for (x = 0; x < sizeof(Block); ++x) { 227 if ((*p++ = fbp->temp_feed[x]) == IAC) 228 *p++ = IAC; 229 } 230 *p++ = IAC; 231 *p++ = SE; 232 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 233 net_write(fbp->fb_feed, p - fbp->fb_feed); 234 break; 235 default: 236 return(FAILED); 237 } 238 return(fbp->state[dir-1] = state); 239} 240 241/* 242 * Returns: 243 * -1: some error. Negotiation is done, encryption not ready. 244 * 0: Successful, initial negotiation all done. 245 * 1: successful, negotiation not done yet. 246 */ 247int 248cfb64_is(unsigned char *data, int cnt) 249{ 250 return(fb64_is(data, cnt, &fb[CFB])); 251} 252 253int 254ofb64_is(unsigned char *data, int cnt) 255{ 256 return(fb64_is(data, cnt, &fb[OFB])); 257} 258 259int 260fb64_is(unsigned char *data, int cnt, struct fb *fbp) 261{ 262 unsigned char *p; 263 int state = fbp->state[DIR_DECRYPT-1]; 264 265 if (cnt-- < 1) 266 goto failure; 267 268 switch (*data++) { 269 case FB64_IV: 270 if (cnt != sizeof(Block)) { 271 if (encrypt_debug_mode) 272 printf("CFB64: initial vector failed on size\r\n"); 273 state = FAILED; 274 goto failure; 275 } 276 277 if (encrypt_debug_mode) 278 printf("CFB64: initial vector received\r\n"); 279 280 if (encrypt_debug_mode) 281 printf("Initializing Decrypt stream\r\n"); 282 283 fb64_stream_iv((void *)data, &fbp->streams[DIR_DECRYPT-1]); 284 285 p = fbp->fb_feed + 3; 286 *p++ = ENCRYPT_REPLY; 287 p++; 288 *p++ = FB64_IV_OK; 289 *p++ = IAC; 290 *p++ = SE; 291 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 292 net_write(fbp->fb_feed, p - fbp->fb_feed); 293 294 state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS; 295 break; 296 297 default: 298 if (encrypt_debug_mode) { 299 printf("Unknown option type: %d\r\n", *(data-1)); 300 printd(data, cnt); 301 printf("\r\n"); 302 } 303 /* FALL THROUGH */ 304 failure: 305 /* 306 * We failed. Send an FB64_IV_BAD option 307 * to the other side so it will know that 308 * things failed. 309 */ 310 p = fbp->fb_feed + 3; 311 *p++ = ENCRYPT_REPLY; 312 p++; 313 *p++ = FB64_IV_BAD; 314 *p++ = IAC; 315 *p++ = SE; 316 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 317 net_write(fbp->fb_feed, p - fbp->fb_feed); 318 319 break; 320 } 321 return(fbp->state[DIR_DECRYPT-1] = state); 322} 323 324/* 325 * Returns: 326 * -1: some error. Negotiation is done, encryption not ready. 327 * 0: Successful, initial negotiation all done. 328 * 1: successful, negotiation not done yet. 329 */ 330int 331cfb64_reply(unsigned char *data, int cnt) 332{ 333 return(fb64_reply(data, cnt, &fb[CFB])); 334} 335 336int 337ofb64_reply(unsigned char *data, int cnt) 338{ 339 return(fb64_reply(data, cnt, &fb[OFB])); 340} 341 342int 343fb64_reply(unsigned char *data, int cnt, struct fb *fbp) 344{ 345 int state = fbp->state[DIR_ENCRYPT-1]; 346 347 if (cnt-- < 1) 348 goto failure; 349 350 switch (*data++) { 351 case FB64_IV_OK: 352 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 353 if (state == FAILED) 354 state = IN_PROGRESS; 355 state &= ~NO_RECV_IV; 356 encrypt_send_keyid(DIR_ENCRYPT, "\0", 1, 1); 357 break; 358 359 case FB64_IV_BAD: 360 memset(fbp->temp_feed, 0, sizeof(Block)); 361 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 362 state = FAILED; 363 break; 364 365 default: 366 if (encrypt_debug_mode) { 367 printf("Unknown option type: %d\r\n", data[-1]); 368 printd(data, cnt); 369 printf("\r\n"); 370 } 371 /* FALL THROUGH */ 372 failure: 373 state = FAILED; 374 break; 375 } 376 return(fbp->state[DIR_ENCRYPT-1] = state); 377} 378 379void 380cfb64_session(Session_Key *key, int server) 381{ 382 fb64_session(key, server, &fb[CFB]); 383} 384 385void 386ofb64_session(Session_Key *key, int server) 387{ 388 fb64_session(key, server, &fb[OFB]); 389} 390 391static void 392fb64_session(Session_Key *key, int server, struct fb *fbp) 393{ 394 if (!key || key->type != SK_DES) { 395 if (encrypt_debug_mode) 396 printf("Can't set krbdes's session key (%d != %d)\r\n", 397 key ? key->type : -1, SK_DES); 398 return; 399 } 400 memmove((void *)fbp->krbdes_key, (void *)key->data, sizeof(Block)); 401 402 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]); 403 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]); 404 405 if (fbp->once == 0) { 406 des_set_random_generator_seed(fbp->krbdes_key); 407 fbp->once = 1; 408 } 409 des_key_sched(fbp->krbdes_key, fbp->krbdes_sched); 410 /* 411 * Now look to see if krbdes_start() was was waiting for 412 * the key to show up. If so, go ahead an call it now 413 * that we have the key. 414 */ 415 if (fbp->need_start) { 416 fbp->need_start = 0; 417 fb64_start(fbp, DIR_ENCRYPT, server); 418 } 419} 420 421/* 422 * We only accept a keyid of 0. If we get a keyid of 423 * 0, then mark the state as SUCCESS. 424 */ 425int 426cfb64_keyid(int dir, unsigned char *kp, int *lenp) 427{ 428 return(fb64_keyid(dir, kp, lenp, &fb[CFB])); 429} 430 431int 432ofb64_keyid(int dir, unsigned char *kp, int *lenp) 433{ 434 return(fb64_keyid(dir, kp, lenp, &fb[OFB])); 435} 436 437int 438fb64_keyid(int dir, unsigned char *kp, int *lenp, struct fb *fbp) 439{ 440 int state = fbp->state[dir-1]; 441 442 if (*lenp != 1 || (*kp != '\0')) { 443 *lenp = 0; 444 return(state); 445 } 446 447 if (state == FAILED) 448 state = IN_PROGRESS; 449 450 state &= ~NO_KEYID; 451 452 return(fbp->state[dir-1] = state); 453} 454 455void 456fb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen, const char *type) 457{ 458 char lbuf[32]; 459 int i; 460 char *cp; 461 462 buf[buflen-1] = '\0'; /* make sure it's NULL terminated */ 463 buflen -= 1; 464 465 switch(data[2]) { 466 case FB64_IV: 467 sprintf(lbuf, "%s_IV", type); 468 cp = lbuf; 469 goto common; 470 471 case FB64_IV_OK: 472 sprintf(lbuf, "%s_IV_OK", type); 473 cp = lbuf; 474 goto common; 475 476 case FB64_IV_BAD: 477 sprintf(lbuf, "%s_IV_BAD", type); 478 cp = lbuf; 479 goto common; 480 481 default: 482 sprintf(lbuf, " %d (unknown)", data[2]); 483 cp = lbuf; 484 common: 485 for (; (buflen > 0) && (*buf = *cp++); buf++) 486 buflen--; 487 for (i = 3; i < cnt; i++) { 488 sprintf(lbuf, " %d", data[i]); 489 for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++) 490 buflen--; 491 } 492 break; 493 } 494} 495 496void 497cfb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen) 498{ 499 fb64_printsub(data, cnt, buf, buflen, "CFB64"); 500} 501 502void 503ofb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen) 504{ 505 fb64_printsub(data, cnt, buf, buflen, "OFB64"); 506} 507 508void 509fb64_stream_iv(Block seed, struct stinfo *stp) 510{ 511 512 memmove((void *)stp->str_iv, (void *)seed, sizeof(Block)); 513 memmove((void *)stp->str_output, (void *)seed, sizeof(Block)); 514 515 des_key_sched(stp->str_ikey, stp->str_sched); 516 517 stp->str_index = sizeof(Block); 518} 519 520void 521fb64_stream_key(Block key, struct stinfo *stp) 522{ 523 memmove((void *)stp->str_ikey, (void *)key, sizeof(Block)); 524 des_key_sched(key, stp->str_sched); 525 526 memmove((void *)stp->str_output, (void *)stp->str_iv, sizeof(Block)); 527 528 stp->str_index = sizeof(Block); 529} 530 531/* 532 * DES 64 bit Cipher Feedback 533 * 534 * key --->+-----+ 535 * +->| DES |--+ 536 * | +-----+ | 537 * | v 538 * INPUT --(--------->(+)+---> DATA 539 * | | 540 * +-------------+ 541 * 542 * 543 * Given: 544 * iV: Initial vector, 64 bits (8 bytes) long. 545 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 546 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 547 * 548 * V0 = DES(iV, key) 549 * On = Dn ^ Vn 550 * V(n+1) = DES(On, key) 551 */ 552 553void 554cfb64_encrypt(unsigned char *s, int c) 555{ 556 struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1]; 557 int idx; 558 559 idx = stp->str_index; 560 while (c-- > 0) { 561 if (idx == sizeof(Block)) { 562 Block b; 563 des_ecb_encrypt((Block *)stp->str_output, (Block *)b, stp->str_sched, 1); 564 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 565 idx = 0; 566 } 567 568 /* On encryption, we store (feed ^ data) which is cypher */ 569 *s = stp->str_output[idx] = (stp->str_feed[idx] ^ *s); 570 s++; 571 idx++; 572 } 573 stp->str_index = idx; 574} 575 576int 577cfb64_decrypt(int data) 578{ 579 struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1]; 580 int idx; 581 582 if (data == -1) { 583 /* 584 * Back up one byte. It is assumed that we will 585 * never back up more than one byte. If we do, this 586 * may or may not work. 587 */ 588 if (stp->str_index) 589 --stp->str_index; 590 return(0); 591 } 592 593 idx = stp->str_index++; 594 if (idx == sizeof(Block)) { 595 Block b; 596 des_ecb_encrypt((Block *)stp->str_output, (Block *)b, stp->str_sched, 1); 597 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 598 stp->str_index = 1; /* Next time will be 1 */ 599 idx = 0; /* But now use 0 */ 600 } 601 602 /* On decryption we store (data) which is cypher. */ 603 stp->str_output[idx] = data; 604 return(data ^ stp->str_feed[idx]); 605} 606 607/* 608 * DES 64 bit Output Feedback 609 * 610 * key --->+-----+ 611 * +->| DES |--+ 612 * | +-----+ | 613 * +-----------+ 614 * v 615 * INPUT -------->(+) ----> DATA 616 * 617 * Given: 618 * iV: Initial vector, 64 bits (8 bytes) long. 619 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 620 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 621 * 622 * V0 = DES(iV, key) 623 * V(n+1) = DES(Vn, key) 624 * On = Dn ^ Vn 625 */ 626void 627ofb64_encrypt(unsigned char *s, int c) 628{ 629 struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1]; 630 int idx; 631 632 idx = stp->str_index; 633 while (c-- > 0) { 634 if (idx == sizeof(Block)) { 635 Block b; 636 des_ecb_encrypt((Block *)stp->str_feed, (Block *)b, stp->str_sched, 1); 637 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 638 idx = 0; 639 } 640 *s++ ^= stp->str_feed[idx]; 641 idx++; 642 } 643 stp->str_index = idx; 644} 645 646int 647ofb64_decrypt(int data) 648{ 649 struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1]; 650 int idx; 651 652 if (data == -1) { 653 /* 654 * Back up one byte. It is assumed that we will 655 * never back up more than one byte. If we do, this 656 * may or may not work. 657 */ 658 if (stp->str_index) 659 --stp->str_index; 660 return(0); 661 } 662 663 idx = stp->str_index++; 664 if (idx == sizeof(Block)) { 665 Block b; 666 des_ecb_encrypt((Block *)stp->str_feed, (Block *)b, stp->str_sched, 1); 667 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 668 stp->str_index = 1; /* Next time will be 1 */ 669 idx = 0; /* But now use 0 */ 670 } 671 672 return(data ^ stp->str_feed[idx]); 673} 674# endif /* AUTHENTICATION */ 675#endif /* ENCRYPTION */ 676