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