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 14681 2005-03-23 16:19:31Z lha $"); 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#include "crypto-headers.h" 54 55extern int encrypt_debug_mode; 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 68struct stinfo { 69 DES_cblock str_output; 70 DES_cblock str_feed; 71 DES_cblock str_iv; 72 DES_cblock str_ikey; 73 DES_key_schedule str_sched; 74 int str_index; 75 int str_flagshift; 76}; 77 78struct fb { 79 DES_cblock krbdes_key; 80 DES_key_schedule krbdes_sched; 81 DES_cblock temp_feed; 82 unsigned char fb_feed[64]; 83 int need_start; 84 int state[2]; 85 int keyid[2]; 86 int once; 87 struct stinfo streams[2]; 88}; 89 90static struct fb fb[2]; 91 92struct keyidlist { 93 char *keyid; 94 int keyidlen; 95 char *key; 96 int keylen; 97 int flags; 98} keyidlist [] = { 99 { "\0", 1, 0, 0, 0 }, /* default key of zero */ 100 { 0, 0, 0, 0, 0 } 101}; 102 103#define KEYFLAG_MASK 03 104 105#define KEYFLAG_NOINIT 00 106#define KEYFLAG_INIT 01 107#define KEYFLAG_OK 02 108#define KEYFLAG_BAD 03 109 110#define KEYFLAG_SHIFT 2 111 112#define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2))) 113 114#define FB64_IV 1 115#define FB64_IV_OK 2 116#define FB64_IV_BAD 3 117 118 119void fb64_stream_iv (DES_cblock, struct stinfo *); 120void fb64_init (struct fb *); 121static int fb64_start (struct fb *, int, int); 122int fb64_is (unsigned char *, int, struct fb *); 123int fb64_reply (unsigned char *, int, struct fb *); 124static void fb64_session (Session_Key *, int, struct fb *); 125void fb64_stream_key (DES_cblock, struct stinfo *); 126int fb64_keyid (int, unsigned char *, int *, struct fb *); 127void fb64_printsub(unsigned char *, int , 128 unsigned char *, int , char *); 129 130void cfb64_init(int server) 131{ 132 fb64_init(&fb[CFB]); 133 fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64; 134 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB); 135 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB); 136} 137 138 139void ofb64_init(int server) 140{ 141 fb64_init(&fb[OFB]); 142 fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64; 143 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB); 144 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB); 145} 146 147void fb64_init(struct fb *fbp) 148{ 149 memset(fbp,0, sizeof(*fbp)); 150 fbp->state[0] = fbp->state[1] = FAILED; 151 fbp->fb_feed[0] = IAC; 152 fbp->fb_feed[1] = SB; 153 fbp->fb_feed[2] = TELOPT_ENCRYPT; 154 fbp->fb_feed[3] = ENCRYPT_IS; 155} 156 157/* 158 * Returns: 159 * -1: some error. Negotiation is done, encryption not ready. 160 * 0: Successful, initial negotiation all done. 161 * 1: successful, negotiation not done yet. 162 * 2: Not yet. Other things (like getting the key from 163 * Kerberos) have to happen before we can continue. 164 */ 165int cfb64_start(int dir, int server) 166{ 167 return(fb64_start(&fb[CFB], dir, server)); 168} 169 170int ofb64_start(int dir, int server) 171{ 172 return(fb64_start(&fb[OFB], dir, server)); 173} 174 175static int fb64_start(struct fb *fbp, int dir, int server) 176{ 177 int x; 178 unsigned char *p; 179 int state; 180 181 switch (dir) { 182 case DIR_DECRYPT: 183 /* 184 * This is simply a request to have the other side 185 * start output (our input). He will negotiate an 186 * IV so we need not look for it. 187 */ 188 state = fbp->state[dir-1]; 189 if (state == FAILED) 190 state = IN_PROGRESS; 191 break; 192 193 case DIR_ENCRYPT: 194 state = fbp->state[dir-1]; 195 if (state == FAILED) 196 state = IN_PROGRESS; 197 else if ((state & NO_SEND_IV) == 0) { 198 break; 199 } 200 201 if (!VALIDKEY(fbp->krbdes_key)) { 202 fbp->need_start = 1; 203 break; 204 } 205 206 state &= ~NO_SEND_IV; 207 state |= NO_RECV_IV; 208 if (encrypt_debug_mode) 209 printf("Creating new feed\r\n"); 210 /* 211 * Create a random feed and send it over. 212 */ 213#ifndef OLD_DES_RANDOM_KEY 214 DES_random_key(&fbp->temp_feed); 215#else 216 /* 217 * From des_cryp.man "If the des_check_key flag is non-zero, 218 * des_set_key will check that the key passed is 219 * of odd parity and is not a week or semi-weak key." 220 */ 221 do { 222 DES_random_key(fbp->temp_feed); 223 DES_set_odd_parity(fbp->temp_feed); 224 } while (DES_is_weak_key(fbp->temp_feed)); 225#endif 226 DES_ecb_encrypt(&fbp->temp_feed, 227 &fbp->temp_feed, 228 &fbp->krbdes_sched, 1); 229 p = fbp->fb_feed + 3; 230 *p++ = ENCRYPT_IS; 231 p++; 232 *p++ = FB64_IV; 233 for (x = 0; x < sizeof(DES_cblock); ++x) { 234 if ((*p++ = fbp->temp_feed[x]) == IAC) 235 *p++ = IAC; 236 } 237 *p++ = IAC; 238 *p++ = SE; 239 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 240 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 241 break; 242 default: 243 return(FAILED); 244 } 245 return(fbp->state[dir-1] = state); 246} 247 248/* 249 * Returns: 250 * -1: some error. Negotiation is done, encryption not ready. 251 * 0: Successful, initial negotiation all done. 252 * 1: successful, negotiation not done yet. 253 */ 254 255int cfb64_is(unsigned char *data, int cnt) 256{ 257 return(fb64_is(data, cnt, &fb[CFB])); 258} 259 260int ofb64_is(unsigned char *data, int cnt) 261{ 262 return(fb64_is(data, cnt, &fb[OFB])); 263} 264 265 266int fb64_is(unsigned char *data, int cnt, struct fb *fbp) 267{ 268 unsigned char *p; 269 int state = fbp->state[DIR_DECRYPT-1]; 270 271 if (cnt-- < 1) 272 goto failure; 273 274 switch (*data++) { 275 case FB64_IV: 276 if (cnt != sizeof(DES_cblock)) { 277 if (encrypt_debug_mode) 278 printf("CFB64: initial vector failed on size\r\n"); 279 state = FAILED; 280 goto failure; 281 } 282 283 if (encrypt_debug_mode) 284 printf("CFB64: initial vector received\r\n"); 285 286 if (encrypt_debug_mode) 287 printf("Initializing Decrypt stream\r\n"); 288 289 fb64_stream_iv(data, &fbp->streams[DIR_DECRYPT-1]); 290 291 p = fbp->fb_feed + 3; 292 *p++ = ENCRYPT_REPLY; 293 p++; 294 *p++ = FB64_IV_OK; 295 *p++ = IAC; 296 *p++ = SE; 297 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 298 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 299 300 state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS; 301 break; 302 303 default: 304 if (encrypt_debug_mode) { 305 printf("Unknown option type: %d\r\n", *(data-1)); 306 printd(data, cnt); 307 printf("\r\n"); 308 } 309 /* FALL THROUGH */ 310 failure: 311 /* 312 * We failed. Send an FB64_IV_BAD option 313 * to the other side so it will know that 314 * things failed. 315 */ 316 p = fbp->fb_feed + 3; 317 *p++ = ENCRYPT_REPLY; 318 p++; 319 *p++ = FB64_IV_BAD; 320 *p++ = IAC; 321 *p++ = SE; 322 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 323 telnet_net_write(fbp->fb_feed, p - fbp->fb_feed); 324 325 break; 326 } 327 return(fbp->state[DIR_DECRYPT-1] = state); 328} 329 330/* 331 * Returns: 332 * -1: some error. Negotiation is done, encryption not ready. 333 * 0: Successful, initial negotiation all done. 334 * 1: successful, negotiation not done yet. 335 */ 336 337int cfb64_reply(unsigned char *data, int cnt) 338{ 339 return(fb64_reply(data, cnt, &fb[CFB])); 340} 341 342int ofb64_reply(unsigned char *data, int cnt) 343{ 344 return(fb64_reply(data, cnt, &fb[OFB])); 345} 346 347 348int fb64_reply(unsigned char *data, int cnt, struct fb *fbp) 349{ 350 int state = fbp->state[DIR_ENCRYPT-1]; 351 352 if (cnt-- < 1) 353 goto failure; 354 355 switch (*data++) { 356 case FB64_IV_OK: 357 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 358 if (state == FAILED) 359 state = IN_PROGRESS; 360 state &= ~NO_RECV_IV; 361 encrypt_send_keyid(DIR_ENCRYPT, (unsigned char *)"\0", 1, 1); 362 break; 363 364 case FB64_IV_BAD: 365 memset(fbp->temp_feed, 0, sizeof(DES_cblock)); 366 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 367 state = FAILED; 368 break; 369 370 default: 371 if (encrypt_debug_mode) { 372 printf("Unknown option type: %d\r\n", data[-1]); 373 printd(data, cnt); 374 printf("\r\n"); 375 } 376 /* FALL THROUGH */ 377 failure: 378 state = FAILED; 379 break; 380 } 381 return(fbp->state[DIR_ENCRYPT-1] = state); 382} 383 384void cfb64_session(Session_Key *key, int server) 385{ 386 fb64_session(key, server, &fb[CFB]); 387} 388 389void ofb64_session(Session_Key *key, int server) 390{ 391 fb64_session(key, server, &fb[OFB]); 392} 393 394static void fb64_session(Session_Key *key, int server, struct fb *fbp) 395{ 396 397 if (!key || key->type != SK_DES) { 398 if (encrypt_debug_mode) 399 printf("Can't set krbdes's session key (%d != %d)\r\n", 400 key ? key->type : -1, SK_DES); 401 return; 402 } 403 memcpy(fbp->krbdes_key, key->data, sizeof(DES_cblock)); 404 405 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]); 406 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]); 407 408 if (fbp->once == 0) { 409#if !defined(OLD_DES_RANDOM_KEY) && !defined(HAVE_OPENSSL) 410 DES_init_random_number_generator(&fbp->krbdes_key); 411#endif 412 fbp->once = 1; 413 } 414 DES_set_key_checked((DES_cblock *)&fbp->krbdes_key, 415 &fbp->krbdes_sched); 416 /* 417 * Now look to see if krbdes_start() was was waiting for 418 * the key to show up. If so, go ahead an call it now 419 * that we have the key. 420 */ 421 if (fbp->need_start) { 422 fbp->need_start = 0; 423 fb64_start(fbp, DIR_ENCRYPT, server); 424 } 425} 426 427/* 428 * We only accept a keyid of 0. If we get a keyid of 429 * 0, then mark the state as SUCCESS. 430 */ 431 432int cfb64_keyid(int dir, unsigned char *kp, int *lenp) 433{ 434 return(fb64_keyid(dir, kp, lenp, &fb[CFB])); 435} 436 437int ofb64_keyid(int dir, unsigned char *kp, int *lenp) 438{ 439 return(fb64_keyid(dir, kp, lenp, &fb[OFB])); 440} 441 442int fb64_keyid(int dir, unsigned char *kp, int *lenp, struct fb *fbp) 443{ 444 int state = fbp->state[dir-1]; 445 446 if (*lenp != 1 || (*kp != '\0')) { 447 *lenp = 0; 448 return(state); 449 } 450 451 if (state == FAILED) 452 state = IN_PROGRESS; 453 454 state &= ~NO_KEYID; 455 456 return(fbp->state[dir-1] = state); 457} 458 459void fb64_printsub(unsigned char *data, int cnt, 460 unsigned char *buf, int buflen, char *type) 461{ 462 char lbuf[32]; 463 int i; 464 char *cp; 465 466 buf[buflen-1] = '\0'; /* make sure it's NULL terminated */ 467 buflen -= 1; 468 469 switch(data[2]) { 470 case FB64_IV: 471 snprintf(lbuf, sizeof(lbuf), "%s_IV", type); 472 cp = lbuf; 473 goto common; 474 475 case FB64_IV_OK: 476 snprintf(lbuf, sizeof(lbuf), "%s_IV_OK", type); 477 cp = lbuf; 478 goto common; 479 480 case FB64_IV_BAD: 481 snprintf(lbuf, sizeof(lbuf), "%s_IV_BAD", type); 482 cp = lbuf; 483 goto common; 484 485 default: 486 snprintf(lbuf, sizeof(lbuf), " %d (unknown)", data[2]); 487 cp = lbuf; 488 common: 489 for (; (buflen > 0) && (*buf = *cp++); buf++) 490 buflen--; 491 for (i = 3; i < cnt; i++) { 492 snprintf(lbuf, sizeof(lbuf), " %d", data[i]); 493 for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++) 494 buflen--; 495 } 496 break; 497 } 498} 499 500void cfb64_printsub(unsigned char *data, int cnt, 501 unsigned char *buf, int buflen) 502{ 503 fb64_printsub(data, cnt, buf, buflen, "CFB64"); 504} 505 506void ofb64_printsub(unsigned char *data, int cnt, 507 unsigned char *buf, int buflen) 508{ 509 fb64_printsub(data, cnt, buf, buflen, "OFB64"); 510} 511 512void fb64_stream_iv(DES_cblock seed, struct stinfo *stp) 513{ 514 515 memcpy(stp->str_iv, seed,sizeof(DES_cblock)); 516 memcpy(stp->str_output, seed, sizeof(DES_cblock)); 517 518 DES_set_key_checked(&stp->str_ikey, &stp->str_sched); 519 520 stp->str_index = sizeof(DES_cblock); 521} 522 523void fb64_stream_key(DES_cblock key, struct stinfo *stp) 524{ 525 memcpy(stp->str_ikey, key, sizeof(DES_cblock)); 526 DES_set_key_checked((DES_cblock*)key, &stp->str_sched); 527 528 memcpy(stp->str_output, stp->str_iv, sizeof(DES_cblock)); 529 530 stp->str_index = sizeof(DES_cblock); 531} 532 533/* 534 * DES 64 bit Cipher Feedback 535 * 536 * key --->+-----+ 537 * +->| DES |--+ 538 * | +-----+ | 539 * | v 540 * INPUT --(--------->(+)+---> DATA 541 * | | 542 * +-------------+ 543 * 544 * 545 * Given: 546 * iV: Initial vector, 64 bits (8 bytes) long. 547 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 548 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 549 * 550 * V0 = DES(iV, key) 551 * On = Dn ^ Vn 552 * V(n+1) = DES(On, key) 553 */ 554 555void cfb64_encrypt(unsigned char *s, int c) 556{ 557 struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1]; 558 int index; 559 560 index = stp->str_index; 561 while (c-- > 0) { 562 if (index == sizeof(DES_cblock)) { 563 DES_cblock b; 564 DES_ecb_encrypt(&stp->str_output, &b,&stp->str_sched, 1); 565 memcpy(stp->str_feed, b, sizeof(DES_cblock)); 566 index = 0; 567 } 568 569 /* On encryption, we store (feed ^ data) which is cypher */ 570 *s = stp->str_output[index] = (stp->str_feed[index] ^ *s); 571 s++; 572 index++; 573 } 574 stp->str_index = index; 575} 576 577int cfb64_decrypt(int data) 578{ 579 struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1]; 580 int index; 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 index = stp->str_index++; 594 if (index == sizeof(DES_cblock)) { 595 DES_cblock b; 596 DES_ecb_encrypt(&stp->str_output,&b, &stp->str_sched, 1); 597 memcpy(stp->str_feed, b, sizeof(DES_cblock)); 598 stp->str_index = 1; /* Next time will be 1 */ 599 index = 0; /* But now use 0 */ 600 } 601 602 /* On decryption we store (data) which is cypher. */ 603 stp->str_output[index] = data; 604 return(data ^ stp->str_feed[index]); 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 */ 626 627void ofb64_encrypt(unsigned char *s, int c) 628{ 629 struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1]; 630 int index; 631 632 index = stp->str_index; 633 while (c-- > 0) { 634 if (index == sizeof(DES_cblock)) { 635 DES_cblock b; 636 DES_ecb_encrypt(&stp->str_feed,&b, &stp->str_sched, 1); 637 memcpy(stp->str_feed, b, sizeof(DES_cblock)); 638 index = 0; 639 } 640 *s++ ^= stp->str_feed[index]; 641 index++; 642 } 643 stp->str_index = index; 644} 645 646int ofb64_decrypt(int data) 647{ 648 struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1]; 649 int index; 650 651 if (data == -1) { 652 /* 653 * Back up one byte. It is assumed that we will 654 * never back up more than one byte. If we do, this 655 * may or may not work. 656 */ 657 if (stp->str_index) 658 --stp->str_index; 659 return(0); 660 } 661 662 index = stp->str_index++; 663 if (index == sizeof(DES_cblock)) { 664 DES_cblock b; 665 DES_ecb_encrypt(&stp->str_feed,&b,&stp->str_sched, 1); 666 memcpy(stp->str_feed, b, sizeof(DES_cblock)); 667 stp->str_index = 1; /* Next time will be 1 */ 668 index = 0; /* But now use 0 */ 669 } 670 671 return(data ^ stp->str_feed[index]); 672} 673#endif 674 675