enc_des.c revision 90926
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#include <config.h> 35 36RCSID("$Id: enc_des.c,v 1.20 2001/08/29 00:45:19 assar Exp $"); 37 38#if defined(AUTHENTICATION) && defined(ENCRYPTION) && defined(DES_ENCRYPTION) 39#include <arpa/telnet.h> 40#include <stdio.h> 41#ifdef __STDC__ 42#include <stdlib.h> 43#include <string.h> 44#endif 45#include <roken.h> 46#ifdef SOCKS 47#include <socks.h> 48#endif 49 50#include "encrypt.h" 51#include "misc-proto.h" 52 53#ifdef HAVE_OPENSSL 54#include <openssl/des.h> 55#else 56#include <des.h> 57#endif 58 59extern int encrypt_debug_mode; 60 61#define CFB 0 62#define OFB 1 63 64#define NO_SEND_IV 1 65#define NO_RECV_IV 2 66#define NO_KEYID 4 67#define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID) 68#define SUCCESS 0 69#define FAILED -1 70 71 72struct stinfo { 73 des_cblock str_output; 74 des_cblock str_feed; 75 des_cblock str_iv; 76 des_cblock str_ikey; 77 des_key_schedule str_sched; 78 int str_index; 79 int str_flagshift; 80}; 81 82struct fb { 83 des_cblock krbdes_key; 84 des_key_schedule krbdes_sched; 85 des_cblock temp_feed; 86 unsigned char fb_feed[64]; 87 int need_start; 88 int state[2]; 89 int keyid[2]; 90 int once; 91 struct stinfo streams[2]; 92}; 93 94static struct fb fb[2]; 95 96struct keyidlist { 97 char *keyid; 98 int keyidlen; 99 char *key; 100 int keylen; 101 int flags; 102} keyidlist [] = { 103 { "\0", 1, 0, 0, 0 }, /* default key of zero */ 104 { 0, 0, 0, 0, 0 } 105}; 106 107#define KEYFLAG_MASK 03 108 109#define KEYFLAG_NOINIT 00 110#define KEYFLAG_INIT 01 111#define KEYFLAG_OK 02 112#define KEYFLAG_BAD 03 113 114#define KEYFLAG_SHIFT 2 115 116#define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2))) 117 118#define FB64_IV 1 119#define FB64_IV_OK 2 120#define FB64_IV_BAD 3 121 122 123void fb64_stream_iv (des_cblock, struct stinfo *); 124void fb64_init (struct fb *); 125static int fb64_start (struct fb *, int, int); 126int fb64_is (unsigned char *, int, struct fb *); 127int fb64_reply (unsigned char *, int, struct fb *); 128static void fb64_session (Session_Key *, int, struct fb *); 129void fb64_stream_key (des_cblock, struct stinfo *); 130int fb64_keyid (int, unsigned char *, int *, struct fb *); 131void fb64_printsub(unsigned char *, int , 132 unsigned char *, int , char *); 133 134void cfb64_init(int server) 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} 141 142 143void ofb64_init(int server) 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 fb64_init(struct fb *fbp) 152{ 153 memset(fbp,0, sizeof(*fbp)); 154 fbp->state[0] = fbp->state[1] = FAILED; 155 fbp->fb_feed[0] = IAC; 156 fbp->fb_feed[1] = SB; 157 fbp->fb_feed[2] = TELOPT_ENCRYPT; 158 fbp->fb_feed[3] = ENCRYPT_IS; 159} 160 161/* 162 * Returns: 163 * -1: some error. Negotiation is done, encryption not ready. 164 * 0: Successful, initial negotiation all done. 165 * 1: successful, negotiation not done yet. 166 * 2: Not yet. Other things (like getting the key from 167 * Kerberos) have to happen before we can continue. 168 */ 169int cfb64_start(int dir, int server) 170{ 171 return(fb64_start(&fb[CFB], dir, server)); 172} 173 174int ofb64_start(int dir, int server) 175{ 176 return(fb64_start(&fb[OFB], dir, server)); 177} 178 179static int fb64_start(struct fb *fbp, int dir, int server) 180{ 181 int x; 182 unsigned char *p; 183 int state; 184 185 switch (dir) { 186 case DIR_DECRYPT: 187 /* 188 * This is simply a request to have the other side 189 * start output (our input). He will negotiate an 190 * IV so we need not look for it. 191 */ 192 state = fbp->state[dir-1]; 193 if (state == FAILED) 194 state = IN_PROGRESS; 195 break; 196 197 case DIR_ENCRYPT: 198 state = fbp->state[dir-1]; 199 if (state == FAILED) 200 state = IN_PROGRESS; 201 else if ((state & NO_SEND_IV) == 0) { 202 break; 203 } 204 205 if (!VALIDKEY(fbp->krbdes_key)) { 206 fbp->need_start = 1; 207 break; 208 } 209 210 state &= ~NO_SEND_IV; 211 state |= NO_RECV_IV; 212 if (encrypt_debug_mode) 213 printf("Creating new feed\r\n"); 214 /* 215 * Create a random feed and send it over. 216 */ 217#ifndef OLD_DES_RANDOM_KEY 218 des_new_random_key(&fbp->temp_feed); 219#else 220 /* 221 * From des_cryp.man "If the des_check_key flag is non-zero, 222 * des_set_key will check that the key passed is 223 * of odd parity and is not a week or semi-weak key." 224 */ 225 do { 226 des_random_key(fbp->temp_feed); 227 des_set_odd_parity(fbp->temp_feed); 228 } while (des_is_weak_key(fbp->temp_feed)); 229#endif 230 des_ecb_encrypt(&fbp->temp_feed, 231 &fbp->temp_feed, 232 fbp->krbdes_sched, 1); 233 p = fbp->fb_feed + 3; 234 *p++ = ENCRYPT_IS; 235 p++; 236 *p++ = FB64_IV; 237 for (x = 0; x < sizeof(des_cblock); ++x) { 238 if ((*p++ = fbp->temp_feed[x]) == IAC) 239 *p++ = IAC; 240 } 241 *p++ = IAC; 242 *p++ = SE; 243 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 244 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 245 break; 246 default: 247 return(FAILED); 248 } 249 return(fbp->state[dir-1] = state); 250} 251 252/* 253 * Returns: 254 * -1: some error. Negotiation is done, encryption not ready. 255 * 0: Successful, initial negotiation all done. 256 * 1: successful, negotiation not done yet. 257 */ 258 259int cfb64_is(unsigned char *data, int cnt) 260{ 261 return(fb64_is(data, cnt, &fb[CFB])); 262} 263 264int ofb64_is(unsigned char *data, int cnt) 265{ 266 return(fb64_is(data, cnt, &fb[OFB])); 267} 268 269 270int fb64_is(unsigned char *data, int cnt, struct fb *fbp) 271{ 272 unsigned char *p; 273 int state = fbp->state[DIR_DECRYPT-1]; 274 275 if (cnt-- < 1) 276 goto failure; 277 278 switch (*data++) { 279 case FB64_IV: 280 if (cnt != sizeof(des_cblock)) { 281 if (encrypt_debug_mode) 282 printf("CFB64: initial vector failed on size\r\n"); 283 state = FAILED; 284 goto failure; 285 } 286 287 if (encrypt_debug_mode) 288 printf("CFB64: initial vector received\r\n"); 289 290 if (encrypt_debug_mode) 291 printf("Initializing Decrypt stream\r\n"); 292 293 fb64_stream_iv(data, &fbp->streams[DIR_DECRYPT-1]); 294 295 p = fbp->fb_feed + 3; 296 *p++ = ENCRYPT_REPLY; 297 p++; 298 *p++ = FB64_IV_OK; 299 *p++ = IAC; 300 *p++ = SE; 301 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 302 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 303 304 state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS; 305 break; 306 307 default: 308 if (encrypt_debug_mode) { 309 printf("Unknown option type: %d\r\n", *(data-1)); 310 printd(data, cnt); 311 printf("\r\n"); 312 } 313 /* FALL THROUGH */ 314 failure: 315 /* 316 * We failed. Send an FB64_IV_BAD option 317 * to the other side so it will know that 318 * things failed. 319 */ 320 p = fbp->fb_feed + 3; 321 *p++ = ENCRYPT_REPLY; 322 p++; 323 *p++ = FB64_IV_BAD; 324 *p++ = IAC; 325 *p++ = SE; 326 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 327 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 328 329 break; 330 } 331 return(fbp->state[DIR_DECRYPT-1] = state); 332} 333 334/* 335 * Returns: 336 * -1: some error. Negotiation is done, encryption not ready. 337 * 0: Successful, initial negotiation all done. 338 * 1: successful, negotiation not done yet. 339 */ 340 341int cfb64_reply(unsigned char *data, int cnt) 342{ 343 return(fb64_reply(data, cnt, &fb[CFB])); 344} 345 346int ofb64_reply(unsigned char *data, int cnt) 347{ 348 return(fb64_reply(data, cnt, &fb[OFB])); 349} 350 351 352int fb64_reply(unsigned char *data, int cnt, struct fb *fbp) 353{ 354 int state = fbp->state[DIR_ENCRYPT-1]; 355 356 if (cnt-- < 1) 357 goto failure; 358 359 switch (*data++) { 360 case FB64_IV_OK: 361 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 362 if (state == FAILED) 363 state = IN_PROGRESS; 364 state &= ~NO_RECV_IV; 365 encrypt_send_keyid(DIR_ENCRYPT, (unsigned char *)"\0", 1, 1); 366 break; 367 368 case FB64_IV_BAD: 369 memset(fbp->temp_feed, 0, sizeof(des_cblock)); 370 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 371 state = FAILED; 372 break; 373 374 default: 375 if (encrypt_debug_mode) { 376 printf("Unknown option type: %d\r\n", data[-1]); 377 printd(data, cnt); 378 printf("\r\n"); 379 } 380 /* FALL THROUGH */ 381 failure: 382 state = FAILED; 383 break; 384 } 385 return(fbp->state[DIR_ENCRYPT-1] = state); 386} 387 388void cfb64_session(Session_Key *key, int server) 389{ 390 fb64_session(key, server, &fb[CFB]); 391} 392 393void ofb64_session(Session_Key *key, int server) 394{ 395 fb64_session(key, server, &fb[OFB]); 396} 397 398static void fb64_session(Session_Key *key, int server, struct fb *fbp) 399{ 400 401 if (!key || key->type != SK_DES) { 402 if (encrypt_debug_mode) 403 printf("Can't set krbdes's session key (%d != %d)\r\n", 404 key ? key->type : -1, SK_DES); 405 return; 406 } 407 memcpy(fbp->krbdes_key, key->data, sizeof(des_cblock)); 408 409 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]); 410 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]); 411 412 if (fbp->once == 0) { 413#if !defined(OLD_DES_RANDOM_KEY) && !defined(HAVE_OPENSSL) 414 des_init_random_number_generator(&fbp->krbdes_key); 415#endif 416 fbp->once = 1; 417 } 418 des_key_sched(&fbp->krbdes_key, fbp->krbdes_sched); 419 /* 420 * Now look to see if krbdes_start() was was waiting for 421 * the key to show up. If so, go ahead an call it now 422 * that we have the key. 423 */ 424 if (fbp->need_start) { 425 fbp->need_start = 0; 426 fb64_start(fbp, DIR_ENCRYPT, server); 427 } 428} 429 430/* 431 * We only accept a keyid of 0. If we get a keyid of 432 * 0, then mark the state as SUCCESS. 433 */ 434 435int cfb64_keyid(int dir, unsigned char *kp, int *lenp) 436{ 437 return(fb64_keyid(dir, kp, lenp, &fb[CFB])); 438} 439 440int ofb64_keyid(int dir, unsigned char *kp, int *lenp) 441{ 442 return(fb64_keyid(dir, kp, lenp, &fb[OFB])); 443} 444 445int fb64_keyid(int dir, unsigned char *kp, int *lenp, struct fb *fbp) 446{ 447 int state = fbp->state[dir-1]; 448 449 if (*lenp != 1 || (*kp != '\0')) { 450 *lenp = 0; 451 return(state); 452 } 453 454 if (state == FAILED) 455 state = IN_PROGRESS; 456 457 state &= ~NO_KEYID; 458 459 return(fbp->state[dir-1] = state); 460} 461 462void fb64_printsub(unsigned char *data, int cnt, 463 unsigned char *buf, int buflen, char *type) 464{ 465 char lbuf[32]; 466 int i; 467 char *cp; 468 469 buf[buflen-1] = '\0'; /* make sure it's NULL terminated */ 470 buflen -= 1; 471 472 switch(data[2]) { 473 case FB64_IV: 474 snprintf(lbuf, sizeof(lbuf), "%s_IV", type); 475 cp = lbuf; 476 goto common; 477 478 case FB64_IV_OK: 479 snprintf(lbuf, sizeof(lbuf), "%s_IV_OK", type); 480 cp = lbuf; 481 goto common; 482 483 case FB64_IV_BAD: 484 snprintf(lbuf, sizeof(lbuf), "%s_IV_BAD", type); 485 cp = lbuf; 486 goto common; 487 488 default: 489 snprintf(lbuf, sizeof(lbuf), " %d (unknown)", data[2]); 490 cp = lbuf; 491 common: 492 for (; (buflen > 0) && (*buf = *cp++); buf++) 493 buflen--; 494 for (i = 3; i < cnt; i++) { 495 snprintf(lbuf, sizeof(lbuf), " %d", data[i]); 496 for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++) 497 buflen--; 498 } 499 break; 500 } 501} 502 503void cfb64_printsub(unsigned char *data, int cnt, 504 unsigned char *buf, int buflen) 505{ 506 fb64_printsub(data, cnt, buf, buflen, "CFB64"); 507} 508 509void ofb64_printsub(unsigned char *data, int cnt, 510 unsigned char *buf, int buflen) 511{ 512 fb64_printsub(data, cnt, buf, buflen, "OFB64"); 513} 514 515void fb64_stream_iv(des_cblock seed, struct stinfo *stp) 516{ 517 518 memcpy(stp->str_iv, seed,sizeof(des_cblock)); 519 memcpy(stp->str_output, seed, sizeof(des_cblock)); 520 521 des_key_sched(&stp->str_ikey, stp->str_sched); 522 523 stp->str_index = sizeof(des_cblock); 524} 525 526void fb64_stream_key(des_cblock key, struct stinfo *stp) 527{ 528 memcpy(stp->str_ikey, key, sizeof(des_cblock)); 529 des_key_sched((des_cblock*)key, stp->str_sched); 530 531 memcpy(stp->str_output, stp->str_iv, sizeof(des_cblock)); 532 533 stp->str_index = sizeof(des_cblock); 534} 535 536/* 537 * DES 64 bit Cipher Feedback 538 * 539 * key --->+-----+ 540 * +->| DES |--+ 541 * | +-----+ | 542 * | v 543 * INPUT --(--------->(+)+---> DATA 544 * | | 545 * +-------------+ 546 * 547 * 548 * Given: 549 * iV: Initial vector, 64 bits (8 bytes) long. 550 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 551 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 552 * 553 * V0 = DES(iV, key) 554 * On = Dn ^ Vn 555 * V(n+1) = DES(On, key) 556 */ 557 558void cfb64_encrypt(unsigned char *s, int c) 559{ 560 struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1]; 561 int index; 562 563 index = stp->str_index; 564 while (c-- > 0) { 565 if (index == sizeof(des_cblock)) { 566 des_cblock b; 567 des_ecb_encrypt(&stp->str_output, &b,stp->str_sched, 1); 568 memcpy(stp->str_feed, b, sizeof(des_cblock)); 569 index = 0; 570 } 571 572 /* On encryption, we store (feed ^ data) which is cypher */ 573 *s = stp->str_output[index] = (stp->str_feed[index] ^ *s); 574 s++; 575 index++; 576 } 577 stp->str_index = index; 578} 579 580int cfb64_decrypt(int data) 581{ 582 struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1]; 583 int index; 584 585 if (data == -1) { 586 /* 587 * Back up one byte. It is assumed that we will 588 * never back up more than one byte. If we do, this 589 * may or may not work. 590 */ 591 if (stp->str_index) 592 --stp->str_index; 593 return(0); 594 } 595 596 index = stp->str_index++; 597 if (index == sizeof(des_cblock)) { 598 des_cblock b; 599 des_ecb_encrypt(&stp->str_output,&b, stp->str_sched, 1); 600 memcpy(stp->str_feed, b, sizeof(des_cblock)); 601 stp->str_index = 1; /* Next time will be 1 */ 602 index = 0; /* But now use 0 */ 603 } 604 605 /* On decryption we store (data) which is cypher. */ 606 stp->str_output[index] = data; 607 return(data ^ stp->str_feed[index]); 608} 609 610/* 611 * DES 64 bit Output Feedback 612 * 613 * key --->+-----+ 614 * +->| DES |--+ 615 * | +-----+ | 616 * +-----------+ 617 * v 618 * INPUT -------->(+) ----> DATA 619 * 620 * Given: 621 * iV: Initial vector, 64 bits (8 bytes) long. 622 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 623 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 624 * 625 * V0 = DES(iV, key) 626 * V(n+1) = DES(Vn, key) 627 * On = Dn ^ Vn 628 */ 629 630void ofb64_encrypt(unsigned char *s, int c) 631{ 632 struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1]; 633 int index; 634 635 index = stp->str_index; 636 while (c-- > 0) { 637 if (index == sizeof(des_cblock)) { 638 des_cblock b; 639 des_ecb_encrypt(&stp->str_feed,&b, stp->str_sched, 1); 640 memcpy(stp->str_feed, b, sizeof(des_cblock)); 641 index = 0; 642 } 643 *s++ ^= stp->str_feed[index]; 644 index++; 645 } 646 stp->str_index = index; 647} 648 649int ofb64_decrypt(int data) 650{ 651 struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1]; 652 int index; 653 654 if (data == -1) { 655 /* 656 * Back up one byte. It is assumed that we will 657 * never back up more than one byte. If we do, this 658 * may or may not work. 659 */ 660 if (stp->str_index) 661 --stp->str_index; 662 return(0); 663 } 664 665 index = stp->str_index++; 666 if (index == sizeof(des_cblock)) { 667 des_cblock b; 668 des_ecb_encrypt(&stp->str_feed,&b,stp->str_sched, 1); 669 memcpy(stp->str_feed, b, sizeof(des_cblock)); 670 stp->str_index = 1; /* Next time will be 1 */ 671 index = 0; /* But now use 0 */ 672 } 673 674 return(data ^ stp->str_feed[index]); 675} 676#endif 677 678