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