1 /* $OpenBSD: kex.c,v 1.91 2013/05/17 00:13:13 djm Exp $ */ 2 /* $FreeBSD$ */ 3 /* 4 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #include <sys/param.h> 30 31 #include <signal.h> 32 #include <stdarg.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 #include <string.h> 36 37 #include <openssl/crypto.h> 38 39 #include "xmalloc.h" 40 #include "ssh2.h" 41 #include "buffer.h" 42 #include "packet.h" 43 #include "compat.h" 44 #include "cipher.h" 45 #include "key.h" 46 #include "kex.h" 47 #include "log.h" 48 #include "mac.h" 49 #include "match.h" 50 #include "dispatch.h" 51 #include "monitor.h" 52 #include "roaming.h" 53 54 #if OPENSSL_VERSION_NUMBER >= 0x00907000L 55 # if defined(HAVE_EVP_SHA256) 56 # define evp_ssh_sha256 EVP_sha256 57 # else 58 extern const EVP_MD *evp_ssh_sha256(void); 59 # endif 60 #endif 61 62 /* prototype */ 63 static void kex_kexinit_finish(Kex *); 64 static void kex_choose_conf(Kex *); 65 66 struct kexalg { 67 char *name; 68 int type; 69 int ec_nid; 70 const EVP_MD *(*mdfunc)(void); 71 }; 72 static const struct kexalg kexalgs[] = { 73 { KEX_DH1, KEX_DH_GRP1_SHA1, 0, EVP_sha1 }, 74 { KEX_DH14, KEX_DH_GRP14_SHA1, 0, EVP_sha1 }, 75 { KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, EVP_sha1 }, 76 #ifdef HAVE_EVP_SHA256 77 { KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, EVP_sha256 }, 78 #endif 79 #ifdef OPENSSL_HAS_ECC 80 { KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2, NID_X9_62_prime256v1, EVP_sha256 }, 81 { KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1, EVP_sha384 }, 82 { KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1, EVP_sha512 }, 83 #endif 84 { NULL, -1, -1, NULL}, 85 }; 86 87 char * 88 kex_alg_list(void) 89 { 90 char *ret = NULL; 91 size_t nlen, rlen = 0; 92 const struct kexalg *k; 93 94 for (k = kexalgs; k->name != NULL; k++) { 95 if (ret != NULL) 96 ret[rlen++] = '\n'; 97 nlen = strlen(k->name); 98 ret = xrealloc(ret, 1, rlen + nlen + 2); 99 memcpy(ret + rlen, k->name, nlen + 1); 100 rlen += nlen; 101 } 102 return ret; 103 } 104 105 static const struct kexalg * 106 kex_alg_by_name(const char *name) 107 { 108 const struct kexalg *k; 109 110 for (k = kexalgs; k->name != NULL; k++) { 111 if (strcmp(k->name, name) == 0) 112 return k; 113 } 114 return NULL; 115 } 116 117 /* Validate KEX method name list */ 118 int 119 kex_names_valid(const char *names) 120 { 121 char *s, *cp, *p; 122 123 if (names == NULL || strcmp(names, "") == 0) 124 return 0; 125 s = cp = xstrdup(names); 126 for ((p = strsep(&cp, ",")); p && *p != '\0'; 127 (p = strsep(&cp, ","))) { 128 if (kex_alg_by_name(p) == NULL) { 129 error("Unsupported KEX algorithm \"%.100s\"", p); 130 free(s); 131 return 0; 132 } 133 } 134 debug3("kex names ok: [%s]", names); 135 free(s); 136 return 1; 137 } 138 139 /* put algorithm proposal into buffer. */ 140 #ifndef NONE_CIPHER_ENABLED 141 static void 142 #else 143 /* Also used in sshconnect2.c. */ 144 void 145 #endif 146 kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) 147 { 148 u_int i; 149 150 buffer_clear(b); 151 /* 152 * add a dummy cookie, the cookie will be overwritten by 153 * kex_send_kexinit(), each time a kexinit is set 154 */ 155 for (i = 0; i < KEX_COOKIE_LEN; i++) 156 buffer_put_char(b, 0); 157 for (i = 0; i < PROPOSAL_MAX; i++) 158 buffer_put_cstring(b, proposal[i]); 159 buffer_put_char(b, 0); /* first_kex_packet_follows */ 160 buffer_put_int(b, 0); /* uint32 reserved */ 161 } 162 163 /* parse buffer and return algorithm proposal */ 164 static char ** 165 kex_buf2prop(Buffer *raw, int *first_kex_follows) 166 { 167 Buffer b; 168 u_int i; 169 char **proposal; 170 171 proposal = xcalloc(PROPOSAL_MAX, sizeof(char *)); 172 173 buffer_init(&b); 174 buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); 175 /* skip cookie */ 176 for (i = 0; i < KEX_COOKIE_LEN; i++) 177 buffer_get_char(&b); 178 /* extract kex init proposal strings */ 179 for (i = 0; i < PROPOSAL_MAX; i++) { 180 proposal[i] = buffer_get_cstring(&b,NULL); 181 debug2("kex_parse_kexinit: %s", proposal[i]); 182 } 183 /* first kex follows / reserved */ 184 i = buffer_get_char(&b); 185 if (first_kex_follows != NULL) 186 *first_kex_follows = i; 187 debug2("kex_parse_kexinit: first_kex_follows %d ", i); 188 i = buffer_get_int(&b); 189 debug2("kex_parse_kexinit: reserved %u ", i); 190 buffer_free(&b); 191 return proposal; 192 } 193 194 static void 195 kex_prop_free(char **proposal) 196 { 197 u_int i; 198 199 for (i = 0; i < PROPOSAL_MAX; i++) 200 free(proposal[i]); 201 free(proposal); 202 } 203 204 /* ARGSUSED */ 205 static void 206 kex_protocol_error(int type, u_int32_t seq, void *ctxt) 207 { 208 error("Hm, kex protocol error: type %d seq %u", type, seq); 209 } 210 211 static void 212 kex_reset_dispatch(void) 213 { 214 dispatch_range(SSH2_MSG_TRANSPORT_MIN, 215 SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); 216 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 217 } 218 219 void 220 kex_finish(Kex *kex) 221 { 222 kex_reset_dispatch(); 223 224 packet_start(SSH2_MSG_NEWKEYS); 225 packet_send(); 226 /* packet_write_wait(); */ 227 debug("SSH2_MSG_NEWKEYS sent"); 228 229 debug("expecting SSH2_MSG_NEWKEYS"); 230 packet_read_expect(SSH2_MSG_NEWKEYS); 231 packet_check_eom(); 232 debug("SSH2_MSG_NEWKEYS received"); 233 234 kex->done = 1; 235 buffer_clear(&kex->peer); 236 /* buffer_clear(&kex->my); */ 237 kex->flags &= ~KEX_INIT_SENT; 238 free(kex->name); 239 kex->name = NULL; 240 } 241 242 void 243 kex_send_kexinit(Kex *kex) 244 { 245 u_int32_t rnd = 0; 246 u_char *cookie; 247 u_int i; 248 249 if (kex == NULL) { 250 error("kex_send_kexinit: no kex, cannot rekey"); 251 return; 252 } 253 if (kex->flags & KEX_INIT_SENT) { 254 debug("KEX_INIT_SENT"); 255 return; 256 } 257 kex->done = 0; 258 259 /* generate a random cookie */ 260 if (buffer_len(&kex->my) < KEX_COOKIE_LEN) 261 fatal("kex_send_kexinit: kex proposal too short"); 262 cookie = buffer_ptr(&kex->my); 263 for (i = 0; i < KEX_COOKIE_LEN; i++) { 264 if (i % 4 == 0) 265 rnd = arc4random(); 266 cookie[i] = rnd; 267 rnd >>= 8; 268 } 269 packet_start(SSH2_MSG_KEXINIT); 270 packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); 271 packet_send(); 272 debug("SSH2_MSG_KEXINIT sent"); 273 kex->flags |= KEX_INIT_SENT; 274 } 275 276 /* ARGSUSED */ 277 void 278 kex_input_kexinit(int type, u_int32_t seq, void *ctxt) 279 { 280 char *ptr; 281 u_int i, dlen; 282 Kex *kex = (Kex *)ctxt; 283 284 debug("SSH2_MSG_KEXINIT received"); 285 if (kex == NULL) 286 fatal("kex_input_kexinit: no kex, cannot rekey"); 287 288 ptr = packet_get_raw(&dlen); 289 buffer_append(&kex->peer, ptr, dlen); 290 291 /* discard packet */ 292 for (i = 0; i < KEX_COOKIE_LEN; i++) 293 packet_get_char(); 294 for (i = 0; i < PROPOSAL_MAX; i++) 295 free(packet_get_string(NULL)); 296 /* 297 * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported 298 * KEX method has the server move first, but a server might be using 299 * a custom method or one that we otherwise don't support. We should 300 * be prepared to remember first_kex_follows here so we can eat a 301 * packet later. 302 * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means 303 * for cases where the server *doesn't* go first. I guess we should 304 * ignore it when it is set for these cases, which is what we do now. 305 */ 306 (void) packet_get_char(); /* first_kex_follows */ 307 (void) packet_get_int(); /* reserved */ 308 packet_check_eom(); 309 310 kex_kexinit_finish(kex); 311 } 312 313 Kex * 314 kex_setup(char *proposal[PROPOSAL_MAX]) 315 { 316 Kex *kex; 317 318 kex = xcalloc(1, sizeof(*kex)); 319 buffer_init(&kex->peer); 320 buffer_init(&kex->my); 321 kex_prop2buf(&kex->my, proposal); 322 kex->done = 0; 323 324 kex_send_kexinit(kex); /* we start */ 325 kex_reset_dispatch(); 326 327 return kex; 328 } 329 330 static void 331 kex_kexinit_finish(Kex *kex) 332 { 333 if (!(kex->flags & KEX_INIT_SENT)) 334 kex_send_kexinit(kex); 335 336 kex_choose_conf(kex); 337 338 if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX && 339 kex->kex[kex->kex_type] != NULL) { 340 (kex->kex[kex->kex_type])(kex); 341 } else { 342 fatal("Unsupported key exchange %d", kex->kex_type); 343 } 344 } 345 346 static void 347 choose_enc(Enc *enc, char *client, char *server) 348 { 349 char *name = match_list(client, server, NULL); 350 if (name == NULL) 351 fatal("no matching cipher found: client %s server %s", 352 client, server); 353 if ((enc->cipher = cipher_by_name(name)) == NULL) 354 fatal("matching cipher is not supported: %s", name); 355 enc->name = name; 356 enc->enabled = 0; 357 enc->iv = NULL; 358 enc->iv_len = cipher_ivlen(enc->cipher); 359 enc->key = NULL; 360 enc->key_len = cipher_keylen(enc->cipher); 361 enc->block_size = cipher_blocksize(enc->cipher); 362 } 363 364 static void 365 choose_mac(Mac *mac, char *client, char *server) 366 { 367 char *name = match_list(client, server, NULL); 368 if (name == NULL) 369 fatal("no matching mac found: client %s server %s", 370 client, server); 371 if (mac_setup(mac, name) < 0) 372 fatal("unsupported mac %s", name); 373 /* truncate the key */ 374 if (datafellows & SSH_BUG_HMAC) 375 mac->key_len = 16; 376 mac->name = name; 377 mac->key = NULL; 378 mac->enabled = 0; 379 } 380 381 static void 382 choose_comp(Comp *comp, char *client, char *server) 383 { 384 char *name = match_list(client, server, NULL); 385 if (name == NULL) 386 fatal("no matching comp found: client %s server %s", client, server); 387 if (strcmp(name, "zlib@openssh.com") == 0) { 388 comp->type = COMP_DELAYED; 389 } else if (strcmp(name, "zlib") == 0) { 390 comp->type = COMP_ZLIB; 391 } else if (strcmp(name, "none") == 0) { 392 comp->type = COMP_NONE; 393 } else { 394 fatal("unsupported comp %s", name); 395 } 396 comp->name = name; 397 } 398 399 static void 400 choose_kex(Kex *k, char *client, char *server) 401 { 402 const struct kexalg *kexalg; 403 404 k->name = match_list(client, server, NULL); 405 if (k->name == NULL) 406 fatal("Unable to negotiate a key exchange method"); 407 if ((kexalg = kex_alg_by_name(k->name)) == NULL) 408 fatal("unsupported kex alg %s", k->name); 409 k->kex_type = kexalg->type; 410 k->evp_md = kexalg->mdfunc(); 411 k->ec_nid = kexalg->ec_nid; 412 } 413 414 static void 415 choose_hostkeyalg(Kex *k, char *client, char *server) 416 { 417 char *hostkeyalg = match_list(client, server, NULL); 418 if (hostkeyalg == NULL) 419 fatal("no hostkey alg"); 420 k->hostkey_type = key_type_from_name(hostkeyalg); 421 if (k->hostkey_type == KEY_UNSPEC) 422 fatal("bad hostkey alg '%s'", hostkeyalg); 423 free(hostkeyalg); 424 } 425 426 static int 427 proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) 428 { 429 static int check[] = { 430 PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 431 }; 432 int *idx; 433 char *p; 434 435 for (idx = &check[0]; *idx != -1; idx++) { 436 if ((p = strchr(my[*idx], ',')) != NULL) 437 *p = '\0'; 438 if ((p = strchr(peer[*idx], ',')) != NULL) 439 *p = '\0'; 440 if (strcmp(my[*idx], peer[*idx]) != 0) { 441 debug2("proposal mismatch: my %s peer %s", 442 my[*idx], peer[*idx]); 443 return (0); 444 } 445 } 446 debug2("proposals match"); 447 return (1); 448 } 449 450 static void 451 kex_choose_conf(Kex *kex) 452 { 453 Newkeys *newkeys; 454 char **my, **peer; 455 char **cprop, **sprop; 456 int nenc, nmac, ncomp; 457 u_int mode, ctos, need, authlen; 458 int first_kex_follows, type; 459 #ifdef NONE_CIPHER_ENABLED 460 int auth_flag; 461 #endif 462 463 my = kex_buf2prop(&kex->my, NULL); 464 peer = kex_buf2prop(&kex->peer, &first_kex_follows); 465 466 if (kex->server) { 467 cprop=peer; 468 sprop=my; 469 } else { 470 cprop=my; 471 sprop=peer; 472 } 473 474 /* Check whether server offers roaming */ 475 if (!kex->server) { 476 char *roaming; 477 roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL); 478 if (roaming) { 479 kex->roaming = 1; 480 free(roaming); 481 } 482 } 483 484 /* Algorithm Negotiation */ 485 #ifdef NONE_CIPHER_ENABLED 486 auth_flag = packet_get_authentication_state(); 487 debug ("AUTH STATE is %d", auth_flag); 488 #endif 489 for (mode = 0; mode < MODE_MAX; mode++) { 490 newkeys = xcalloc(1, sizeof(*newkeys)); 491 kex->newkeys[mode] = newkeys; 492 ctos = (!kex->server && mode == MODE_OUT) || 493 (kex->server && mode == MODE_IN); 494 nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; 495 nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; 496 ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; 497 choose_enc(&newkeys->enc, cprop[nenc], sprop[nenc]); 498 /* ignore mac for authenticated encryption */ 499 authlen = cipher_authlen(newkeys->enc.cipher); 500 if (authlen == 0) 501 choose_mac(&newkeys->mac, cprop[nmac], sprop[nmac]); 502 choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); 503 #ifdef NONE_CIPHER_ENABLED 504 debug("REQUESTED ENC.NAME is '%s'", newkeys->enc.name); 505 if (strcmp(newkeys->enc.name, "none") == 0) { 506 debug("Requesting NONE. Authflag is %d", auth_flag); 507 if (auth_flag == 1) 508 debug("None requested post authentication."); 509 else 510 fatal("Pre-authentication none cipher requests " 511 "are not allowed."); 512 } 513 #endif 514 debug("kex: %s %s %s %s", 515 ctos ? "client->server" : "server->client", 516 newkeys->enc.name, 517 authlen == 0 ? newkeys->mac.name : "<implicit>", 518 newkeys->comp.name); 519 } 520 choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); 521 choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], 522 sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); 523 need = 0; 524 for (mode = 0; mode < MODE_MAX; mode++) { 525 newkeys = kex->newkeys[mode]; 526 if (need < newkeys->enc.key_len) 527 need = newkeys->enc.key_len; 528 if (need < newkeys->enc.block_size) 529 need = newkeys->enc.block_size; 530 if (need < newkeys->enc.iv_len) 531 need = newkeys->enc.iv_len; 532 if (need < newkeys->mac.key_len) 533 need = newkeys->mac.key_len; 534 } 535 /* XXX need runden? */ 536 kex->we_need = need; 537 538 /* ignore the next message if the proposals do not match */ 539 if (first_kex_follows && !proposals_match(my, peer) && 540 !(datafellows & SSH_BUG_FIRSTKEX)) { 541 type = packet_read(); 542 debug2("skipping next packet (type %u)", type); 543 } 544 545 kex_prop_free(my); 546 kex_prop_free(peer); 547 } 548 549 static u_char * 550 derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen, 551 BIGNUM *shared_secret) 552 { 553 Buffer b; 554 EVP_MD_CTX md; 555 char c = id; 556 u_int have; 557 int mdsz; 558 u_char *digest; 559 560 if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0) 561 fatal("bad kex md size %d", mdsz); 562 digest = xmalloc(roundup(need, mdsz)); 563 564 buffer_init(&b); 565 buffer_put_bignum2(&b, shared_secret); 566 567 /* K1 = HASH(K || H || "A" || session_id) */ 568 EVP_DigestInit(&md, kex->evp_md); 569 if (!(datafellows & SSH_BUG_DERIVEKEY)) 570 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 571 EVP_DigestUpdate(&md, hash, hashlen); 572 EVP_DigestUpdate(&md, &c, 1); 573 EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); 574 EVP_DigestFinal(&md, digest, NULL); 575 576 /* 577 * expand key: 578 * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) 579 * Key = K1 || K2 || ... || Kn 580 */ 581 for (have = mdsz; need > have; have += mdsz) { 582 EVP_DigestInit(&md, kex->evp_md); 583 if (!(datafellows & SSH_BUG_DERIVEKEY)) 584 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 585 EVP_DigestUpdate(&md, hash, hashlen); 586 EVP_DigestUpdate(&md, digest, have); 587 EVP_DigestFinal(&md, digest + have, NULL); 588 } 589 buffer_free(&b); 590 #ifdef DEBUG_KEX 591 fprintf(stderr, "key '%c'== ", c); 592 dump_digest("key", digest, need); 593 #endif 594 return digest; 595 } 596 597 Newkeys *current_keys[MODE_MAX]; 598 599 #define NKEYS 6 600 void 601 kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret) 602 { 603 u_char *keys[NKEYS]; 604 u_int i, mode, ctos; 605 606 for (i = 0; i < NKEYS; i++) { 607 keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen, 608 shared_secret); 609 } 610 611 debug2("kex_derive_keys"); 612 for (mode = 0; mode < MODE_MAX; mode++) { 613 current_keys[mode] = kex->newkeys[mode]; 614 kex->newkeys[mode] = NULL; 615 ctos = (!kex->server && mode == MODE_OUT) || 616 (kex->server && mode == MODE_IN); 617 current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; 618 current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; 619 current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; 620 } 621 } 622 623 Newkeys * 624 kex_get_newkeys(int mode) 625 { 626 Newkeys *ret; 627 628 ret = current_keys[mode]; 629 current_keys[mode] = NULL; 630 return ret; 631 } 632 633 void 634 derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus, 635 u_int8_t cookie[8], u_int8_t id[16]) 636 { 637 const EVP_MD *evp_md = EVP_md5(); 638 EVP_MD_CTX md; 639 u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE]; 640 int len; 641 642 EVP_DigestInit(&md, evp_md); 643 644 len = BN_num_bytes(host_modulus); 645 if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) 646 fatal("%s: bad host modulus (len %d)", __func__, len); 647 BN_bn2bin(host_modulus, nbuf); 648 EVP_DigestUpdate(&md, nbuf, len); 649 650 len = BN_num_bytes(server_modulus); 651 if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) 652 fatal("%s: bad server modulus (len %d)", __func__, len); 653 BN_bn2bin(server_modulus, nbuf); 654 EVP_DigestUpdate(&md, nbuf, len); 655 656 EVP_DigestUpdate(&md, cookie, 8); 657 658 EVP_DigestFinal(&md, obuf, NULL); 659 memcpy(id, obuf, 16); 660 661 memset(nbuf, 0, sizeof(nbuf)); 662 memset(obuf, 0, sizeof(obuf)); 663 memset(&md, 0, sizeof(md)); 664 } 665 666 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 667 void 668 dump_digest(char *msg, u_char *digest, int len) 669 { 670 int i; 671 672 fprintf(stderr, "%s\n", msg); 673 for (i = 0; i < len; i++) { 674 fprintf(stderr, "%02x", digest[i]); 675 if (i%32 == 31) 676 fprintf(stderr, "\n"); 677 else if (i%8 == 7) 678 fprintf(stderr, " "); 679 } 680 fprintf(stderr, "\n"); 681 } 682 #endif 683