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 1.3.2.2 2003/02/14 22:38:13 nectar Exp $ 34 * $DragonFly: src/crypto/telnet/libtelnet/enc_des.c,v 1.2 2003/06/17 04:24:37 dillon Exp $ 35 * 36 * @(#)enc_des.c 8.3 (Berkeley) 5/30/95 37 * $FreeBSD: src/crypto/telnet/libtelnet/enc_des.c,v 1.3.2.2 2003/02/14 22:38:13 nectar Exp $ 38 */ 39 40 #ifdef ENCRYPTION 41 # ifdef AUTHENTICATION 42 #include <arpa/telnet.h> 43 #include <openssl/des.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 48 #include "encrypt.h" 49 #include "key-proto.h" 50 #include "misc-proto.h" 51 52 extern int encrypt_debug_mode; 53 54 #define CFB 0 55 #define OFB 1 56 57 #define NO_SEND_IV 1 58 #define NO_RECV_IV 2 59 #define NO_KEYID 4 60 #define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID) 61 #define SUCCESS 0 62 #define FAILED -1 63 64 65 struct fb { 66 Block krbdes_key; 67 Schedule krbdes_sched; 68 Block temp_feed; 69 unsigned char fb_feed[64]; 70 int need_start; 71 int state[2]; 72 int keyid[2]; 73 struct stinfo { 74 Block str_output; 75 Block str_feed; 76 Block str_iv; 77 Block str_ikey; 78 Schedule str_sched; 79 int str_index; 80 int str_flagshift; 81 } streams[2]; 82 }; 83 84 static struct fb fb[2]; 85 86 struct keyidlist { 87 const char *keyid; 88 int keyidlen; 89 char *key; 90 int keylen; 91 int flags; 92 } keyidlist [] = { 93 { "\0", 1, 0, 0, 0 }, /* default key of zero */ 94 { 0, 0, 0, 0, 0 } 95 }; 96 97 #define KEYFLAG_MASK 03 98 99 #define KEYFLAG_NOINIT 00 100 #define KEYFLAG_INIT 01 101 #define KEYFLAG_OK 02 102 #define KEYFLAG_BAD 03 103 104 #define KEYFLAG_SHIFT 2 105 106 #define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2))) 107 108 #define FB64_IV 1 109 #define FB64_IV_OK 2 110 #define FB64_IV_BAD 3 111 112 113 void fb64_stream_iv(Block, struct stinfo *); 114 void fb64_init(struct fb *); 115 static int fb64_start(struct fb *, int, int); 116 int fb64_is(unsigned char *, int, struct fb *); 117 int fb64_reply(unsigned char *, int, struct fb *); 118 static void fb64_session(Session_Key *, int, struct fb *); 119 void fb64_stream_key(Block, struct stinfo *); 120 int fb64_keyid(int, unsigned char *, int *, struct fb *); 121 122 void 123 cfb64_init(int server __unused) 124 { 125 fb64_init(&fb[CFB]); 126 fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64; 127 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB); 128 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB); 129 } 130 131 void 132 ofb64_init(int server __unused) 133 { 134 fb64_init(&fb[OFB]); 135 fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64; 136 fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB); 137 fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB); 138 } 139 140 void 141 fb64_init(struct fb *fbp) 142 { 143 memset((void *)fbp, 0, sizeof(*fbp)); 144 fbp->state[0] = fbp->state[1] = FAILED; 145 fbp->fb_feed[0] = IAC; 146 fbp->fb_feed[1] = SB; 147 fbp->fb_feed[2] = TELOPT_ENCRYPT; 148 fbp->fb_feed[3] = ENCRYPT_IS; 149 } 150 151 /* 152 * Returns: 153 * -1: some error. Negotiation is done, encryption not ready. 154 * 0: Successful, initial negotiation all done. 155 * 1: successful, negotiation not done yet. 156 * 2: Not yet. Other things (like getting the key from 157 * Kerberos) have to happen before we can continue. 158 */ 159 int 160 cfb64_start(int dir, int server) 161 { 162 return(fb64_start(&fb[CFB], dir, server)); 163 } 164 165 int 166 ofb64_start(int dir, int server) 167 { 168 return(fb64_start(&fb[OFB], dir, server)); 169 } 170 171 static int 172 fb64_start(struct fb *fbp, int dir, int server __unused) 173 { 174 size_t x; 175 unsigned char *p; 176 int state; 177 178 switch (dir) { 179 case DIR_DECRYPT: 180 /* 181 * This is simply a request to have the other side 182 * start output (our input). He will negotiate an 183 * IV so we need not look for it. 184 */ 185 state = fbp->state[dir-1]; 186 if (state == FAILED) 187 state = IN_PROGRESS; 188 break; 189 190 case DIR_ENCRYPT: 191 state = fbp->state[dir-1]; 192 if (state == FAILED) 193 state = IN_PROGRESS; 194 else if ((state & NO_SEND_IV) == 0) 195 break; 196 197 if (!VALIDKEY(fbp->krbdes_key)) { 198 fbp->need_start = 1; 199 break; 200 } 201 state &= ~NO_SEND_IV; 202 state |= NO_RECV_IV; 203 if (encrypt_debug_mode) 204 printf("Creating new feed\r\n"); 205 /* 206 * Create a random feed and send it over. 207 */ 208 des_random_key((Block *)fbp->temp_feed); 209 des_ecb_encrypt((Block *)fbp->temp_feed, (Block *)fbp->temp_feed, 210 fbp->krbdes_sched, 1); 211 p = fbp->fb_feed + 3; 212 *p++ = ENCRYPT_IS; 213 p++; 214 *p++ = FB64_IV; 215 for (x = 0; x < sizeof(Block); ++x) { 216 if ((*p++ = fbp->temp_feed[x]) == IAC) 217 *p++ = IAC; 218 } 219 *p++ = IAC; 220 *p++ = SE; 221 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 222 net_write(fbp->fb_feed, p - fbp->fb_feed); 223 break; 224 default: 225 return(FAILED); 226 } 227 return(fbp->state[dir-1] = state); 228 } 229 230 /* 231 * Returns: 232 * -1: some error. Negotiation is done, encryption not ready. 233 * 0: Successful, initial negotiation all done. 234 * 1: successful, negotiation not done yet. 235 */ 236 int 237 cfb64_is(unsigned char *data, int cnt) 238 { 239 return(fb64_is(data, cnt, &fb[CFB])); 240 } 241 242 int 243 ofb64_is(unsigned char *data, int cnt) 244 { 245 return(fb64_is(data, cnt, &fb[OFB])); 246 } 247 248 int 249 fb64_is(unsigned char *data, int cnt, struct fb *fbp) 250 { 251 unsigned char *p; 252 int state = fbp->state[DIR_DECRYPT-1]; 253 254 if (cnt-- < 1) 255 goto failure; 256 257 switch (*data++) { 258 case FB64_IV: 259 if (cnt != sizeof(Block)) { 260 if (encrypt_debug_mode) 261 printf("CFB64: initial vector failed on size\r\n"); 262 state = FAILED; 263 goto failure; 264 } 265 266 if (encrypt_debug_mode) 267 printf("CFB64: initial vector received\r\n"); 268 269 if (encrypt_debug_mode) 270 printf("Initializing Decrypt stream\r\n"); 271 272 fb64_stream_iv((void *)data, &fbp->streams[DIR_DECRYPT-1]); 273 274 p = fbp->fb_feed + 3; 275 *p++ = ENCRYPT_REPLY; 276 p++; 277 *p++ = FB64_IV_OK; 278 *p++ = IAC; 279 *p++ = SE; 280 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 281 net_write(fbp->fb_feed, p - fbp->fb_feed); 282 283 state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS; 284 break; 285 286 default: 287 if (encrypt_debug_mode) { 288 printf("Unknown option type: %d\r\n", *(data-1)); 289 printd(data, cnt); 290 printf("\r\n"); 291 } 292 /* FALL THROUGH */ 293 failure: 294 /* 295 * We failed. Send an FB64_IV_BAD option 296 * to the other side so it will know that 297 * things failed. 298 */ 299 p = fbp->fb_feed + 3; 300 *p++ = ENCRYPT_REPLY; 301 p++; 302 *p++ = FB64_IV_BAD; 303 *p++ = IAC; 304 *p++ = SE; 305 printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]); 306 net_write(fbp->fb_feed, p - fbp->fb_feed); 307 308 break; 309 } 310 return(fbp->state[DIR_DECRYPT-1] = state); 311 } 312 313 /* 314 * Returns: 315 * -1: some error. Negotiation is done, encryption not ready. 316 * 0: Successful, initial negotiation all done. 317 * 1: successful, negotiation not done yet. 318 */ 319 int 320 cfb64_reply(unsigned char *data, int cnt) 321 { 322 return(fb64_reply(data, cnt, &fb[CFB])); 323 } 324 325 int 326 ofb64_reply(unsigned char *data, int cnt) 327 { 328 return(fb64_reply(data, cnt, &fb[OFB])); 329 } 330 331 int 332 fb64_reply(unsigned char *data, int cnt, struct fb *fbp) 333 { 334 int state = fbp->state[DIR_ENCRYPT-1]; 335 336 if (cnt-- < 1) 337 goto failure; 338 339 switch (*data++) { 340 case FB64_IV_OK: 341 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 342 if (state == FAILED) 343 state = IN_PROGRESS; 344 state &= ~NO_RECV_IV; 345 encrypt_send_keyid(DIR_ENCRYPT, "\0", 1, 1); 346 break; 347 348 case FB64_IV_BAD: 349 memset(fbp->temp_feed, 0, sizeof(Block)); 350 fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]); 351 state = FAILED; 352 break; 353 354 default: 355 if (encrypt_debug_mode) { 356 printf("Unknown option type: %d\r\n", data[-1]); 357 printd(data, cnt); 358 printf("\r\n"); 359 } 360 /* FALL THROUGH */ 361 failure: 362 state = FAILED; 363 break; 364 } 365 return(fbp->state[DIR_ENCRYPT-1] = state); 366 } 367 368 void 369 cfb64_session(Session_Key *key, int server) 370 { 371 fb64_session(key, server, &fb[CFB]); 372 } 373 374 void 375 ofb64_session(Session_Key *key, int server) 376 { 377 fb64_session(key, server, &fb[OFB]); 378 } 379 380 static void 381 fb64_session(Session_Key *key, int server, struct fb *fbp) 382 { 383 if (!key || key->type != SK_DES) { 384 if (encrypt_debug_mode) 385 printf("Can't set krbdes's session key (%d != %d)\r\n", 386 key ? key->type : -1, SK_DES); 387 return; 388 } 389 memmove((void *)fbp->krbdes_key, (void *)key->data, sizeof(Block)); 390 391 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]); 392 fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]); 393 394 des_key_sched((Block *)fbp->krbdes_key, fbp->krbdes_sched); 395 /* 396 * Now look to see if krbdes_start() was was waiting for 397 * the key to show up. If so, go ahead an call it now 398 * that we have the key. 399 */ 400 if (fbp->need_start) { 401 fbp->need_start = 0; 402 fb64_start(fbp, DIR_ENCRYPT, server); 403 } 404 } 405 406 /* 407 * We only accept a keyid of 0. If we get a keyid of 408 * 0, then mark the state as SUCCESS. 409 */ 410 int 411 cfb64_keyid(int dir, unsigned char *kp, int *lenp) 412 { 413 return(fb64_keyid(dir, kp, lenp, &fb[CFB])); 414 } 415 416 int 417 ofb64_keyid(int dir, unsigned char *kp, int *lenp) 418 { 419 return(fb64_keyid(dir, kp, lenp, &fb[OFB])); 420 } 421 422 int 423 fb64_keyid(int dir, unsigned char *kp, int *lenp, struct fb *fbp) 424 { 425 int state = fbp->state[dir-1]; 426 427 if (*lenp != 1 || (*kp != '\0')) { 428 *lenp = 0; 429 return(state); 430 } 431 432 if (state == FAILED) 433 state = IN_PROGRESS; 434 435 state &= ~NO_KEYID; 436 437 return(fbp->state[dir-1] = state); 438 } 439 440 void 441 fb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen, const char *type) 442 { 443 char lbuf[32]; 444 int i; 445 char *cp; 446 447 buf[buflen-1] = '\0'; /* make sure it's NULL terminated */ 448 buflen -= 1; 449 450 switch(data[2]) { 451 case FB64_IV: 452 sprintf(lbuf, "%s_IV", type); 453 cp = lbuf; 454 goto common; 455 456 case FB64_IV_OK: 457 sprintf(lbuf, "%s_IV_OK", type); 458 cp = lbuf; 459 goto common; 460 461 case FB64_IV_BAD: 462 sprintf(lbuf, "%s_IV_BAD", type); 463 cp = lbuf; 464 goto common; 465 466 default: 467 sprintf(lbuf, " %d (unknown)", data[2]); 468 cp = lbuf; 469 common: 470 for (; (buflen > 0) && (*buf = *cp++); buf++) 471 buflen--; 472 for (i = 3; i < cnt; i++) { 473 sprintf(lbuf, " %d", data[i]); 474 for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++) 475 buflen--; 476 } 477 break; 478 } 479 } 480 481 void 482 cfb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen) 483 { 484 fb64_printsub(data, cnt, buf, buflen, "CFB64"); 485 } 486 487 void 488 ofb64_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen) 489 { 490 fb64_printsub(data, cnt, buf, buflen, "OFB64"); 491 } 492 493 void 494 fb64_stream_iv(Block seed, struct stinfo *stp) 495 { 496 497 memmove((void *)stp->str_iv, (void *)seed, sizeof(Block)); 498 memmove((void *)stp->str_output, (void *)seed, sizeof(Block)); 499 500 des_key_sched((Block *)stp->str_ikey, stp->str_sched); 501 502 stp->str_index = sizeof(Block); 503 } 504 505 void 506 fb64_stream_key(Block key, struct stinfo *stp) 507 { 508 memmove((void *)stp->str_ikey, (void *)key, sizeof(Block)); 509 des_key_sched((Block *)key, stp->str_sched); 510 511 memmove((void *)stp->str_output, (void *)stp->str_iv, sizeof(Block)); 512 513 stp->str_index = sizeof(Block); 514 } 515 516 /* 517 * DES 64 bit Cipher Feedback 518 * 519 * key --->+-----+ 520 * +->| DES |--+ 521 * | +-----+ | 522 * | v 523 * INPUT --(--------->(+)+---> DATA 524 * | | 525 * +-------------+ 526 * 527 * 528 * Given: 529 * iV: Initial vector, 64 bits (8 bytes) long. 530 * Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt). 531 * On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output. 532 * 533 * V0 = DES(iV, key) 534 * On = Dn ^ Vn 535 * V(n+1) = DES(On, key) 536 */ 537 538 void 539 cfb64_encrypt(unsigned char *s, int c) 540 { 541 struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1]; 542 int idx; 543 544 idx = stp->str_index; 545 while (c-- > 0) { 546 if (idx == sizeof(Block)) { 547 Block b; 548 des_ecb_encrypt((Block *)stp->str_output, (Block *)b, stp->str_sched, 1); 549 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 550 idx = 0; 551 } 552 553 /* On encryption, we store (feed ^ data) which is cypher */ 554 *s = stp->str_output[idx] = (stp->str_feed[idx] ^ *s); 555 s++; 556 idx++; 557 } 558 stp->str_index = idx; 559 } 560 561 int 562 cfb64_decrypt(int data) 563 { 564 struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1]; 565 int idx; 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 idx = stp->str_index++; 579 if (idx == sizeof(Block)) { 580 Block b; 581 des_ecb_encrypt((Block *)stp->str_output, (Block *)b, stp->str_sched, 1); 582 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 583 stp->str_index = 1; /* Next time will be 1 */ 584 idx = 0; /* But now use 0 */ 585 } 586 587 /* On decryption we store (data) which is cypher. */ 588 stp->str_output[idx] = data; 589 return(data ^ stp->str_feed[idx]); 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 void 612 ofb64_encrypt(unsigned char *s, int c) 613 { 614 struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1]; 615 int idx; 616 617 idx = stp->str_index; 618 while (c-- > 0) { 619 if (idx == sizeof(Block)) { 620 Block b; 621 des_ecb_encrypt((Block *)stp->str_feed, (Block *)b, stp->str_sched, 1); 622 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 623 idx = 0; 624 } 625 *s++ ^= stp->str_feed[idx]; 626 idx++; 627 } 628 stp->str_index = idx; 629 } 630 631 int 632 ofb64_decrypt(int data) 633 { 634 struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1]; 635 int idx; 636 637 if (data == -1) { 638 /* 639 * Back up one byte. It is assumed that we will 640 * never back up more than one byte. If we do, this 641 * may or may not work. 642 */ 643 if (stp->str_index) 644 --stp->str_index; 645 return(0); 646 } 647 648 idx = stp->str_index++; 649 if (idx == sizeof(Block)) { 650 Block b; 651 des_ecb_encrypt((Block *)stp->str_feed, (Block *)b, stp->str_sched, 1); 652 memmove((void *)stp->str_feed, (void *)b, sizeof(Block)); 653 stp->str_index = 1; /* Next time will be 1 */ 654 idx = 0; /* But now use 0 */ 655 } 656 657 return(data ^ stp->str_feed[idx]); 658 } 659 # endif /* AUTHENTICATION */ 660 #endif /* ENCRYPTION */ 661