enc_des.c revision 1.11
1 /* $NetBSD: enc_des.c,v 1.11 2003/08/07 16:44:54 agc Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)enc_des.c 8.3 (Berkeley) 5/30/95"; */ 36 #else 37 __RCSID("$NetBSD: enc_des.c,v 1.11 2003/08/07 16:44:54 agc Exp $"); 38 #endif 39 #endif /* not lint */ 40 41 #ifdef ENCRYPTION 42 # ifdef AUTHENTICATION 43 # ifdef DES_ENCRYPTION 44 #include <arpa/telnet.h> 45 #include <stdio.h> 46 #include <string.h> 47 #include <stdlib.h> 48 49 #include <des.h> 50 #include "encrypt.h" 51 #include "key-proto.h" 52 #include "misc-proto.h" 53 54 #include <sys/cdefs.h> 55 #define P __P 56 57 #define CFB 0 58 #define OFB 1 59 60 #define NO_SEND_IV 1 61 #define NO_RECV_IV 2 62 #define NO_KEYID 4 63 #define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID) 64 #define SUCCESS 0 65 #define FAILED -1 66 67 68 struct fb { 69 Block krbdes_key; 70 Schedule krbdes_sched; 71 Block temp_feed; 72 unsigned char fb_feed[64]; 73 int need_start; 74 int state[2]; 75 int keyid[2]; 76 int once; 77 struct stinfo { 78 Block str_output; 79 Block str_feed; 80 Block str_iv; 81 Block str_ikey; 82 Schedule str_sched; 83 int str_index; 84 int str_flagshift; 85 } streams[2]; 86 }; 87 88 static struct fb fb[2]; 89 90 struct keyidlist { 91 char *keyid; 92 int keyidlen; 93 char *key; 94 int keylen; 95 int flags; 96 } keyidlist [] = { 97 { "\0", 1, 0, 0, 0 }, /* default key of zero */ 98 { 0, 0, 0, 0, 0 } 99 }; 100 101 #define KEYFLAG_MASK 03 102 103 #define KEYFLAG_NOINIT 00 104 #define KEYFLAG_INIT 01 105 #define KEYFLAG_OK 02 106 #define KEYFLAG_BAD 03 107 108 #define KEYFLAG_SHIFT 2 109 110 #define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2))) 111 112 #define FB64_IV 1 113 #define FB64_IV_OK 2 114 #define FB64_IV_BAD 3 115 116 117 void fb64_stream_iv P((Block, struct stinfo *)); 118 void fb64_init P((struct fb *)); 119 static int fb64_start P((struct fb *, int, int)); 120 int fb64_is P((unsigned char *, int, struct fb *)); 121 int fb64_reply P((unsigned char *, int, struct fb *)); 122 static void fb64_session P((Session_Key *, int, struct fb *)); 123 void fb64_stream_key P((Block *, struct stinfo *)); 124 int fb64_keyid P((int, unsigned char *, int *, struct fb *)); 125 126 void 127 cfb64_init(server) 128 int server; 129 { 130 fb64_init(&fb[CFB]); 131 fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64; 132 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB); 133 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB); 134 } 135 136 void 137 ofb64_init(server) 138 int server; 139 { 140 fb64_init(&fb[OFB]); 141 fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64; 142 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB); 143 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB); 144 } 145 146 void 147 fb64_init(fbp) 148 register struct fb *fbp; 149 { 150 memset((void *)fbp, 0, sizeof(*fbp)); 151 fbp->state[0] = fbp->state[1] = FAILED; 152 fbp->fb_feed[0] = IAC; 153 fbp->fb_feed[1] = SB; 154 fbp->fb_feed[2] = TELOPT_ENCRYPT; 155 fbp->fb_feed[3] = ENCRYPT_IS; 156 } 157 158 /* 159 * Returns: 160 * -1: some error. Negotiation is done, encryption not ready. 161 * 0: Successful, initial negotiation all done. 162 * 1: successful, negotiation not done yet. 163 * 2: Not yet. Other things (like getting the key from 164 * Kerberos) have to happen before we can continue. 165 */ 166 int 167 cfb64_start(dir, server) 168 int dir; 169 int server; 170 { 171 return(fb64_start(&fb[CFB], dir, server)); 172 } 173 int 174 ofb64_start(dir, server) 175 int dir; 176 int server; 177 { 178 return(fb64_start(&fb[OFB], dir, server)); 179 } 180 181 static int 182 fb64_start(fbp, dir, server) 183 struct fb *fbp; 184 int dir; 185 int server; 186 { 187 int x; 188 unsigned char *p; 189 register int state; 190 191 switch (dir) { 192 case DIR_DECRYPT: 193 /* 194 * This is simply a request to have the other side 195 * start output (our input). He will negotiate an 196 * IV so we need not look for it. 197 */ 198 state = fbp->state[dir-1]; 199 if (state == FAILED) 200 state = IN_PROGRESS; 201 break; 202 203 case DIR_ENCRYPT: 204 state = fbp->state[dir-1]; 205 if (state == FAILED) 206 state = IN_PROGRESS; 207 else if ((state & NO_SEND_IV) == 0) 208 break; 209 210 if (!VALIDKEY(fbp->krbdes_key)) { 211 fbp->need_start = 1; 212 break; 213 } 214 state &= ~NO_SEND_IV; 215 state |= NO_RECV_IV; 216 if (encrypt_debug_mode) 217 printf("Creating new feed\r\n"); 218 /* 219 * Create a random feed and send it over. 220 */ 221 des_new_random_key(&fbp->temp_feed); 222 des_ecb_encrypt(&fbp->temp_feed, &fbp->temp_feed, 223 fbp->krbdes_sched, 1); 224 p = fbp->fb_feed + 3; 225 *p++ = ENCRYPT_IS; 226 p++; 227 *p++ = FB64_IV; 228 for (x = 0; x < sizeof(Block); ++x) { 229 if ((*p++ = fbp->temp_feed[x]) == IAC) 230 *p++ = IAC; 231 } 232 *p++ = IAC; 233 *p++ = SE; 234 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 235 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 236 break; 237 default: 238 return(FAILED); 239 } 240 return(fbp->state[dir-1] = state); 241 } 242 243 /* 244 * Returns: 245 * -1: some error. Negotiation is done, encryption not ready. 246 * 0: Successful, initial negotiation all done. 247 * 1: successful, negotiation not done yet. 248 */ 249 int 250 cfb64_is(data, cnt) 251 unsigned char *data; 252 int cnt; 253 { 254 return(fb64_is(data, cnt, &fb[CFB])); 255 } 256 int 257 ofb64_is(data, cnt) 258 unsigned char *data; 259 int cnt; 260 { 261 return(fb64_is(data, cnt, &fb[OFB])); 262 } 263 264 int 265 fb64_is(data, cnt, fbp) 266 unsigned char *data; 267 int cnt; 268 struct fb *fbp; 269 { 270 unsigned char *p; 271 register int state = fbp->state[DIR_DECRYPT-1]; 272 273 if (cnt-- < 1) 274 goto failure; 275 276 switch (*data++) { 277 case FB64_IV: 278 if (cnt != sizeof(Block)) { 279 if (encrypt_debug_mode) 280 printf("CFB64: initial vector failed on size\r\n"); 281 state = FAILED; 282 goto failure; 283 } 284 285 if (encrypt_debug_mode) 286 printf("CFB64: initial vector received\r\n"); 287 288 if (encrypt_debug_mode) 289 printf("Initializing Decrypt stream\r\n"); 290 291 fb64_stream_iv((void *)data, &fbp->streams[DIR_DECRYPT-1]); 292 293 p = fbp->fb_feed + 3; 294 *p++ = ENCRYPT_REPLY; 295 p++; 296 *p++ = FB64_IV_OK; 297 *p++ = IAC; 298 *p++ = SE; 299 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 300 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 301 302 state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS; 303 break; 304 305 default: 306 if (encrypt_debug_mode) { 307 printf("Unknown option type: %d\r\n", *(data-1)); 308 printd(data, cnt); 309 printf("\r\n"); 310 } 311 /* FALL THROUGH */ 312 failure: 313 /* 314 * We failed. Send an FB64_IV_BAD option 315 * to the other side so it will know that 316 * things failed. 317 */ 318 p = fbp->fb_feed + 3; 319 *p++ = ENCRYPT_REPLY; 320 p++; 321 *p++ = FB64_IV_BAD; 322 *p++ = IAC; 323 *p++ = SE; 324 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 325 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 326 327 break; 328 } 329 return(fbp->state[DIR_DECRYPT-1] = state); 330 } 331 332 /* 333 * Returns: 334 * -1: some error. Negotiation is done, encryption not ready. 335 * 0: Successful, initial negotiation all done. 336 * 1: successful, negotiation not done yet. 337 */ 338 int 339 cfb64_reply(data, cnt) 340 unsigned char *data; 341 int cnt; 342 { 343 return(fb64_reply(data, cnt, &fb[CFB])); 344 } 345 int 346 ofb64_reply(data, cnt) 347 unsigned char *data; 348 int cnt; 349 { 350 return(fb64_reply(data, cnt, &fb[OFB])); 351 } 352 353 354 int 355 fb64_reply(data, cnt, fbp) 356 unsigned char *data; 357 int cnt; 358 struct fb *fbp; 359 { 360 register int state = fbp->state[DIR_ENCRYPT-1]; 361 362 if (cnt-- < 1) 363 goto failure; 364 365 switch (*data++) { 366 case FB64_IV_OK: 367 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 368 if (state == FAILED) 369 state = IN_PROGRESS; 370 state &= ~NO_RECV_IV; 371 encrypt_send_keyid(DIR_ENCRYPT, (unsigned char *)"\0", 1, 1); 372 break; 373 374 case FB64_IV_BAD: 375 memset(fbp->temp_feed, 0, sizeof(Block)); 376 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 377 state = FAILED; 378 break; 379 380 default: 381 if (encrypt_debug_mode) { 382 printf("Unknown option type: %d\r\n", data[-1]); 383 printd(data, cnt); 384 printf("\r\n"); 385 } 386 /* FALL THROUGH */ 387 failure: 388 state = FAILED; 389 break; 390 } 391 return(fbp->state[DIR_ENCRYPT-1] = state); 392 } 393 394 void 395 cfb64_session(key, server) 396 Session_Key *key; 397 int server; 398 { 399 fb64_session(key, server, &fb[CFB]); 400 } 401 402 void 403 ofb64_session(key, server) 404 Session_Key *key; 405 int server; 406 { 407 fb64_session(key, server, &fb[OFB]); 408 } 409 410 static void 411 fb64_session(key, server, fbp) 412 Session_Key *key; 413 int server; 414 struct fb *fbp; 415 { 416 417 if (!key || key->type != SK_DES) { 418 if (encrypt_debug_mode) 419 printf("Can't set krbdes's session key (%d != %d)\r\n", 420 key ? key->type : -1, SK_DES); 421 return; 422 } 423 memmove((void *)fbp->krbdes_key, (void *)key->data, sizeof(Block)); 424 425 fb64_stream_key(&fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]); 426 fb64_stream_key(&fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]); 427 428 if (fbp->once == 0) { 429 des_init_random_number_generator(&fbp->krbdes_key); 430 fbp->once = 1; 431 } 432 des_key_sched(&fbp->krbdes_key, fbp->krbdes_sched); 433 /* 434 * Now look to see if krbdes_start() was was waiting for 435 * the key to show up. If so, go ahead an call it now 436 * that we have the key. 437 */ 438 if (fbp->need_start) { 439 fbp->need_start = 0; 440 fb64_start(fbp, DIR_ENCRYPT, server); 441 } 442 } 443 444 /* 445 * We only accept a keyid of 0. If we get a keyid of 446 * 0, then mark the state as SUCCESS. 447 */ 448 int 449 cfb64_keyid(dir, kp, lenp) 450 int dir, *lenp; 451 unsigned char *kp; 452 { 453 return(fb64_keyid(dir, kp, lenp, &fb[CFB])); 454 } 455 456 int 457 ofb64_keyid(dir, kp, lenp) 458 int dir, *lenp; 459 unsigned char *kp; 460 { 461 return(fb64_keyid(dir, kp, lenp, &fb[OFB])); 462 } 463 464 int 465 fb64_keyid(dir, kp, lenp, fbp) 466 int dir, *lenp; 467 unsigned char *kp; 468 struct fb *fbp; 469 { 470 register int state = fbp->state[dir-1]; 471 472 if (*lenp != 1 || (*kp != '\0')) { 473 *lenp = 0; 474 return(state); 475 } 476 477 if (state == FAILED) 478 state = IN_PROGRESS; 479 480 state &= ~NO_KEYID; 481 482 return(fbp->state[dir-1] = state); 483 } 484 485 void 486 fb64_printsub(data, cnt, buf, buflen, type) 487 unsigned char *data, *buf, *type; 488 int cnt, buflen; 489 { 490 char lbuf[32]; 491 register int i; 492 char *cp; 493 494 buf[buflen-1] = '\0'; /* make sure it's NULL terminated */ 495 buflen -= 1; 496 497 switch(data[2]) { 498 case FB64_IV: 499 snprintf(lbuf, sizeof(lbuf), "%s_IV", type); 500 cp = lbuf; 501 goto common; 502 503 case FB64_IV_OK: 504 snprintf(lbuf, sizeof(lbuf), "%s_IV_OK", type); 505 cp = lbuf; 506 goto common; 507 508 case FB64_IV_BAD: 509 snprintf(lbuf, sizeof(lbuf), "%s_IV_BAD", type); 510 cp = lbuf; 511 goto common; 512 513 default: 514 snprintf(lbuf, sizeof(lbuf), " %d (unknown)", data[2]); 515 cp = lbuf; 516 common: 517 for (; (buflen > 0) && (*buf = *cp++); buf++) 518 buflen--; 519 for (i = 3; i < cnt; i++) { 520 snprintf(lbuf, sizeof(lbuf), " %d", data[i]); 521 for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++) 522 buflen--; 523 } 524 break; 525 } 526 } 527 528 void 529 cfb64_printsub(data, cnt, buf, buflen) 530 unsigned char *data, *buf; 531 int cnt, buflen; 532 { 533 fb64_printsub(data, cnt, buf, buflen, "CFB64"); 534 } 535 536 void 537 ofb64_printsub(data, cnt, buf, buflen) 538 unsigned char *data, *buf; 539 int cnt, buflen; 540 { 541 fb64_printsub(data, cnt, buf, buflen, "OFB64"); 542 } 543 544 void 545 fb64_stream_iv(seed, stp) 546 Block seed; 547 register struct stinfo *stp; 548 { 549 550 memmove((void *)stp->str_iv, (void *)seed, sizeof(Block)); 551 memmove((void *)stp->str_output, (void *)seed, sizeof(Block)); 552 553 des_key_sched(&stp->str_ikey, stp->str_sched); 554 555 stp->str_index = sizeof(Block); 556 } 557 558 void 559 fb64_stream_key(key, stp) 560 Block *key; 561 register struct stinfo *stp; 562 { 563 memmove((void *)stp->str_ikey, (void *)key, sizeof(Block)); 564 des_key_sched(key, stp->str_sched); 565 566 memmove((void *)stp->str_output, (void *)stp->str_iv, sizeof(Block)); 567 568 stp->str_index = sizeof(Block); 569 } 570 571 /* 572 * DES 64 bit Cipher Feedback 573 * 574 * key --->+-----+ 575 * +->| DES |--+ 576 * | +-----+ | 577 * | v 578 * INPUT --(--------->(+)+---> DATA 579 * | | 580 * +-------------+ 581 * 582 * 583 * Given: 584 * iV: Initial vector, 64 bits (8 bytes) long. 585 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 586 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 587 * 588 * V0 = DES(iV, key) 589 * On = Dn ^ Vn 590 * V(n+1) = DES(On, key) 591 */ 592 593 void 594 cfb64_encrypt(s, c) 595 register unsigned char *s; 596 int c; 597 { 598 register struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1]; 599 register int idx; 600 601 idx = stp->str_index; 602 while (c-- > 0) { 603 if (idx == sizeof(Block)) { 604 Block b; 605 des_ecb_encrypt(&stp->str_output, &b, stp->str_sched, 1); 606 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 607 idx = 0; 608 } 609 610 /* On encryption, we store (feed ^ data) which is cypher */ 611 *s = stp->str_output[idx] = (stp->str_feed[idx] ^ *s); 612 s++; 613 idx++; 614 } 615 stp->str_index = idx; 616 } 617 618 int 619 cfb64_decrypt(data) 620 int data; 621 { 622 register struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1]; 623 int idx; 624 625 if (data == -1) { 626 /* 627 * Back up one byte. It is assumed that we will 628 * never back up more than one byte. If we do, this 629 * may or may not work. 630 */ 631 if (stp->str_index) 632 --stp->str_index; 633 return(0); 634 } 635 636 idx = stp->str_index++; 637 if (idx == sizeof(Block)) { 638 Block b; 639 des_ecb_encrypt(&stp->str_output, &b, stp->str_sched, 1); 640 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 641 stp->str_index = 1; /* Next time will be 1 */ 642 idx = 0; /* But now use 0 */ 643 } 644 645 /* On decryption we store (data) which is cypher. */ 646 stp->str_output[idx] = data; 647 return(data ^ stp->str_feed[idx]); 648 } 649 650 /* 651 * DES 64 bit Output Feedback 652 * 653 * key --->+-----+ 654 * +->| DES |--+ 655 * | +-----+ | 656 * +-----------+ 657 * v 658 * INPUT -------->(+) ----> DATA 659 * 660 * Given: 661 * iV: Initial vector, 64 bits (8 bytes) long. 662 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 663 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 664 * 665 * V0 = DES(iV, key) 666 * V(n+1) = DES(Vn, key) 667 * On = Dn ^ Vn 668 */ 669 void 670 ofb64_encrypt(s, c) 671 register unsigned char *s; 672 int c; 673 { 674 register struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1]; 675 register int idx; 676 677 idx = stp->str_index; 678 while (c-- > 0) { 679 if (idx == sizeof(Block)) { 680 Block b; 681 des_ecb_encrypt(&stp->str_feed, &b, stp->str_sched, 1); 682 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 683 idx = 0; 684 } 685 *s++ ^= stp->str_feed[idx]; 686 idx++; 687 } 688 stp->str_index = idx; 689 } 690 691 int 692 ofb64_decrypt(data) 693 int data; 694 { 695 register struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1]; 696 int idx; 697 698 if (data == -1) { 699 /* 700 * Back up one byte. It is assumed that we will 701 * never back up more than one byte. If we do, this 702 * may or may not work. 703 */ 704 if (stp->str_index) 705 --stp->str_index; 706 return(0); 707 } 708 709 idx = stp->str_index++; 710 if (idx == sizeof(Block)) { 711 Block b; 712 des_ecb_encrypt(&stp->str_feed, &b, stp->str_sched, 1); 713 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 714 stp->str_index = 1; /* Next time will be 1 */ 715 idx = 0; /* But now use 0 */ 716 } 717 718 return(data ^ stp->str_feed[idx]); 719 } 720 # endif /* DES_ENCRYPTION */ 721 # endif /* AUTHENTICATION */ 722 #endif /* ENCRYPTION */ 723
Indexes created Tue Sep 23 22:09:46 GMT 2025