1 /* $NetBSD: kex.c,v 1.7 2013/03/29 16:19:45 christos Exp $ */ 2 /* $OpenBSD: kex.c,v 1.88 2013/01/08 18:49:04 markus Exp $ */ 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 __RCSID("$NetBSD: kex.c,v 1.7 2013/03/29 16:19:45 christos Exp $"); 29 #include <sys/param.h> 30 31 #include <signal.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 36 #include <openssl/crypto.h> 37 38 #include "xmalloc.h" 39 #include "ssh2.h" 40 #include "buffer.h" 41 #include "packet.h" 42 #include "compat.h" 43 #include "cipher.h" 44 #include "key.h" 45 #include "kex.h" 46 #include "log.h" 47 #include "mac.h" 48 #include "match.h" 49 #include "dispatch.h" 50 #include "monitor.h" 51 #include "canohost.h" 52 #include "roaming.h" 53 54 /* prototype */ 55 static void kex_kexinit_finish(Kex *); 56 static void kex_choose_conf(Kex *); 57 58 /* Validate KEX method name list */ 59 int 60 kex_names_valid(const char *names) 61 { 62 char *s, *cp, *p; 63 64 if (names == NULL || strcmp(names, "") == 0) 65 return 0; 66 s = cp = xstrdup(names); 67 for ((p = strsep(&cp, ",")); p && *p != '\0'; 68 (p = strsep(&cp, ","))) { 69 if (strcmp(p, KEX_DHGEX_SHA256) != 0 && 70 strcmp(p, KEX_DHGEX_SHA1) != 0 && 71 strcmp(p, KEX_DH14) != 0 && 72 strcmp(p, KEX_DH1) != 0 && 73 (strncmp(p, KEX_ECDH_SHA2_STEM, 74 sizeof(KEX_ECDH_SHA2_STEM) - 1) != 0 || 75 kex_ecdh_name_to_nid(p) == -1)) { 76 error("Unsupported KEX algorithm \"%.100s\"", p); 77 xfree(s); 78 return 0; 79 } 80 } 81 debug3("kex names ok: [%s]", names); 82 xfree(s); 83 return 1; 84 } 85 86 /* put algorithm proposal into buffer */ 87 /* used in sshconnect.c as well as kex.c */ 88 void 89 kex_prop2buf(Buffer *b, const char *proposal[PROPOSAL_MAX]) 90 { 91 u_int i; 92 93 buffer_clear(b); 94 /* 95 * add a dummy cookie, the cookie will be overwritten by 96 * kex_send_kexinit(), each time a kexinit is set 97 */ 98 for (i = 0; i < KEX_COOKIE_LEN; i++) 99 buffer_put_char(b, 0); 100 for (i = 0; i < PROPOSAL_MAX; i++) 101 buffer_put_cstring(b, proposal[i]); 102 buffer_put_char(b, 0); /* first_kex_packet_follows */ 103 buffer_put_int(b, 0); /* uint32 reserved */ 104 } 105 106 /* parse buffer and return algorithm proposal */ 107 static char ** 108 kex_buf2prop(Buffer *raw, int *first_kex_follows) 109 { 110 Buffer b; 111 u_int i; 112 char **proposal; 113 114 proposal = xcalloc(PROPOSAL_MAX, sizeof(char *)); 115 116 buffer_init(&b); 117 buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); 118 /* skip cookie */ 119 for (i = 0; i < KEX_COOKIE_LEN; i++) 120 buffer_get_char(&b); 121 /* extract kex init proposal strings */ 122 for (i = 0; i < PROPOSAL_MAX; i++) { 123 proposal[i] = buffer_get_cstring(&b,NULL); 124 debug2("kex_parse_kexinit: %s", proposal[i]); 125 } 126 /* first kex follows / reserved */ 127 i = buffer_get_char(&b); 128 if (first_kex_follows != NULL) 129 *first_kex_follows = i; 130 debug2("kex_parse_kexinit: first_kex_follows %d ", i); 131 i = buffer_get_int(&b); 132 debug2("kex_parse_kexinit: reserved %u ", i); 133 buffer_free(&b); 134 return proposal; 135 } 136 137 static void 138 kex_prop_free(char **proposal) 139 { 140 u_int i; 141 142 for (i = 0; i < PROPOSAL_MAX; i++) 143 xfree(proposal[i]); 144 xfree(proposal); 145 } 146 147 /* ARGSUSED */ 148 static void 149 kex_protocol_error(int type, u_int32_t seq, void *ctxt) 150 { 151 error("Hm, kex protocol error: type %d seq %u", type, seq); 152 } 153 154 static void 155 kex_reset_dispatch(void) 156 { 157 dispatch_range(SSH2_MSG_TRANSPORT_MIN, 158 SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); 159 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 160 } 161 162 void 163 kex_finish(Kex *kex) 164 { 165 kex_reset_dispatch(); 166 167 packet_start(SSH2_MSG_NEWKEYS); 168 packet_send(); 169 /* packet_write_wait(); */ 170 debug("SSH2_MSG_NEWKEYS sent"); 171 172 debug("expecting SSH2_MSG_NEWKEYS"); 173 packet_read_expect(SSH2_MSG_NEWKEYS); 174 packet_check_eom(); 175 debug("SSH2_MSG_NEWKEYS received"); 176 177 kex->done = 1; 178 buffer_clear(&kex->peer); 179 /* buffer_clear(&kex->my); */ 180 kex->flags &= ~KEX_INIT_SENT; 181 xfree(kex->name); 182 kex->name = NULL; 183 } 184 185 void 186 kex_send_kexinit(Kex *kex) 187 { 188 u_int32_t rnd = 0; 189 u_char *cookie; 190 u_int i; 191 192 if (kex == NULL) { 193 error("kex_send_kexinit: no kex, cannot rekey"); 194 return; 195 } 196 if (kex->flags & KEX_INIT_SENT) { 197 debug("KEX_INIT_SENT"); 198 return; 199 } 200 kex->done = 0; 201 202 /* generate a random cookie */ 203 if (buffer_len(&kex->my) < KEX_COOKIE_LEN) 204 fatal("kex_send_kexinit: kex proposal too short"); 205 cookie = buffer_ptr(&kex->my); 206 for (i = 0; i < KEX_COOKIE_LEN; i++) { 207 if (i % 4 == 0) 208 rnd = arc4random(); 209 cookie[i] = rnd; 210 rnd >>= 8; 211 } 212 packet_start(SSH2_MSG_KEXINIT); 213 packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); 214 packet_send(); 215 debug("SSH2_MSG_KEXINIT sent"); 216 kex->flags |= KEX_INIT_SENT; 217 } 218 219 /* ARGSUSED */ 220 void 221 kex_input_kexinit(int type, u_int32_t seq, void *ctxt) 222 { 223 char *ptr; 224 u_int i, dlen; 225 Kex *kex = (Kex *)ctxt; 226 227 debug("SSH2_MSG_KEXINIT received"); 228 if (kex == NULL) 229 fatal("kex_input_kexinit: no kex, cannot rekey"); 230 231 ptr = packet_get_raw(&dlen); 232 buffer_append(&kex->peer, ptr, dlen); 233 234 /* discard packet */ 235 for (i = 0; i < KEX_COOKIE_LEN; i++) 236 packet_get_char(); 237 for (i = 0; i < PROPOSAL_MAX; i++) 238 xfree(packet_get_string(NULL)); 239 /* 240 * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported 241 * KEX method has the server move first, but a server might be using 242 * a custom method or one that we otherwise don't support. We should 243 * be prepared to remember first_kex_follows here so we can eat a 244 * packet later. 245 * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means 246 * for cases where the server *doesn't* go first. I guess we should 247 * ignore it when it is set for these cases, which is what we do now. 248 */ 249 (void) packet_get_char(); /* first_kex_follows */ 250 (void) packet_get_int(); /* reserved */ 251 packet_check_eom(); 252 253 kex_kexinit_finish(kex); 254 } 255 256 Kex * 257 kex_setup(const char *proposal[PROPOSAL_MAX]) 258 { 259 Kex *kex; 260 261 kex = xcalloc(1, sizeof(*kex)); 262 buffer_init(&kex->peer); 263 buffer_init(&kex->my); 264 kex_prop2buf(&kex->my, proposal); 265 kex->done = 0; 266 267 kex_send_kexinit(kex); /* we start */ 268 kex_reset_dispatch(); 269 270 return kex; 271 } 272 273 static void 274 kex_kexinit_finish(Kex *kex) 275 { 276 if (!(kex->flags & KEX_INIT_SENT)) 277 kex_send_kexinit(kex); 278 279 kex_choose_conf(kex); 280 281 if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX && 282 kex->kex[kex->kex_type] != NULL) { 283 (kex->kex[kex->kex_type])(kex); 284 } else { 285 fatal("Unsupported key exchange %d", kex->kex_type); 286 } 287 } 288 289 static void 290 choose_enc(Enc *enc, char *client, char *server) 291 { 292 char *name = match_list(client, server, NULL); 293 if (name == NULL) 294 fatal("no matching cipher found: client %s server %s", 295 client, server); 296 if ((enc->cipher = cipher_by_name(name)) == NULL) 297 fatal("matching cipher is not supported: %s", name); 298 enc->name = name; 299 enc->enabled = 0; 300 enc->iv = NULL; 301 enc->iv_len = cipher_ivlen(enc->cipher); 302 enc->key = NULL; 303 enc->key_len = cipher_keylen(enc->cipher); 304 enc->block_size = cipher_blocksize(enc->cipher); 305 } 306 307 static void 308 choose_mac(Mac *mac, char *client, char *server) 309 { 310 char *name = match_list(client, server, NULL); 311 if (name == NULL) 312 fatal("no matching mac found: client %s server %s", 313 client, server); 314 if (mac_setup(mac, name) < 0) 315 fatal("unsupported mac %s", name); 316 /* truncate the key */ 317 if (datafellows & SSH_BUG_HMAC) 318 mac->key_len = 16; 319 mac->name = name; 320 mac->key = NULL; 321 mac->enabled = 0; 322 } 323 324 static void 325 choose_comp(Comp *comp, char *client, char *server) 326 { 327 char *name = match_list(client, server, NULL); 328 if (name == NULL) 329 fatal("no matching comp found: client %s server %s", client, server); 330 if (strcmp(name, "zlib@openssh.com") == 0) { 331 comp->type = COMP_DELAYED; 332 } else if (strcmp(name, "zlib") == 0) { 333 comp->type = COMP_ZLIB; 334 } else if (strcmp(name, "none") == 0) { 335 comp->type = COMP_NONE; 336 } else { 337 fatal("unsupported comp %s", name); 338 } 339 comp->name = name; 340 } 341 342 static void 343 choose_kex(Kex *k, char *client, char *server) 344 { 345 k->name = match_list(client, server, NULL); 346 if (k->name == NULL) 347 fatal("Unable to negotiate a key exchange method"); 348 if (strcmp(k->name, KEX_DH1) == 0) { 349 k->kex_type = KEX_DH_GRP1_SHA1; 350 k->evp_md = EVP_sha1(); 351 } else if (strcmp(k->name, KEX_DH14) == 0) { 352 k->kex_type = KEX_DH_GRP14_SHA1; 353 k->evp_md = EVP_sha1(); 354 } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) { 355 k->kex_type = KEX_DH_GEX_SHA1; 356 k->evp_md = EVP_sha1(); 357 } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) { 358 k->kex_type = KEX_DH_GEX_SHA256; 359 k->evp_md = EVP_sha256(); 360 } else if (strncmp(k->name, KEX_ECDH_SHA2_STEM, 361 sizeof(KEX_ECDH_SHA2_STEM) - 1) == 0) { 362 k->kex_type = KEX_ECDH_SHA2; 363 k->evp_md = kex_ecdh_name_to_evpmd(k->name); 364 } else 365 fatal("bad kex alg %s", k->name); 366 } 367 368 static void 369 choose_hostkeyalg(Kex *k, char *client, char *server) 370 { 371 char *hostkeyalg = match_list(client, server, NULL); 372 if (hostkeyalg == NULL) 373 fatal("no hostkey alg"); 374 k->hostkey_type = key_type_from_name(hostkeyalg); 375 if (k->hostkey_type == KEY_UNSPEC) 376 fatal("bad hostkey alg '%s'", hostkeyalg); 377 xfree(hostkeyalg); 378 } 379 380 static int 381 proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) 382 { 383 static int check[] = { 384 PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 385 }; 386 int *idx; 387 char *p; 388 389 for (idx = &check[0]; *idx != -1; idx++) { 390 if ((p = strchr(my[*idx], ',')) != NULL) 391 *p = '\0'; 392 if ((p = strchr(peer[*idx], ',')) != NULL) 393 *p = '\0'; 394 if (strcmp(my[*idx], peer[*idx]) != 0) { 395 debug2("proposal mismatch: my %s peer %s", 396 my[*idx], peer[*idx]); 397 return (0); 398 } 399 } 400 debug2("proposals match"); 401 return (1); 402 } 403 404 static void 405 kex_choose_conf(Kex *kex) 406 { 407 Newkeys *newkeys; 408 char **my, **peer; 409 char **cprop, **sprop; 410 int nenc, nmac, ncomp; 411 u_int mode, ctos, need, authlen; 412 int first_kex_follows, type; 413 int log_flag = 0; 414 415 int auth_flag; 416 417 auth_flag = packet_authentication_state(); 418 419 debug ("AUTH STATE IS %d", auth_flag); 420 421 my = kex_buf2prop(&kex->my, NULL); 422 peer = kex_buf2prop(&kex->peer, &first_kex_follows); 423 424 if (kex->server) { 425 cprop=peer; 426 sprop=my; 427 } else { 428 cprop=my; 429 sprop=peer; 430 } 431 432 /* Check whether server offers roaming */ 433 if (!kex->server) { 434 char *roaming; 435 roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL); 436 if (roaming) { 437 kex->roaming = 1; 438 xfree(roaming); 439 } 440 } 441 442 /* Algorithm Negotiation */ 443 for (mode = 0; mode < MODE_MAX; mode++) { 444 newkeys = xcalloc(1, sizeof(*newkeys)); 445 kex->newkeys[mode] = newkeys; 446 ctos = (!kex->server && mode == MODE_OUT) || 447 (kex->server && mode == MODE_IN); 448 nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; 449 nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; 450 ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; 451 choose_enc(&newkeys->enc, cprop[nenc], sprop[nenc]); 452 /* ignore mac for authenticated encryption */ 453 authlen = cipher_authlen(newkeys->enc.cipher); 454 if (authlen == 0) 455 choose_mac(&newkeys->mac, cprop[nmac], sprop[nmac]); 456 choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); 457 debug("REQUESTED ENC.NAME is '%s'", newkeys->enc.name); 458 if (strcmp(newkeys->enc.name, "none") == 0) { 459 debug("Requesting NONE. Authflag is %d", auth_flag); 460 if (auth_flag == 1) { 461 debug("None requested post authentication."); 462 } else { 463 fatal("Pre-authentication none cipher requests are not allowed."); 464 } 465 } 466 debug("kex: %s %s %s %s", 467 ctos ? "client->server" : "server->client", 468 newkeys->enc.name, 469 authlen == 0 ? newkeys->mac.name : "<implicit>", 470 newkeys->comp.name); 471 /* client starts withctos = 0 && log flag = 0 and no log*/ 472 /* 2nd client pass ctos=1 and flag = 1 so no log*/ 473 /* server starts with ctos =1 && log_flag = 0 so log */ 474 /* 2nd sever pass ctos = 1 && log flag = 1 so no log*/ 475 /* -cjr*/ 476 if (ctos && !log_flag) { 477 logit("SSH: Server;Ltype: Kex;Remote: %s-%d;Enc: %s;MAC: %s;Comp: %s", 478 get_remote_ipaddr(), 479 get_remote_port(), 480 newkeys->enc.name, 481 newkeys->mac.name, 482 newkeys->comp.name); 483 } 484 log_flag = 1; 485 } 486 choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); 487 choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], 488 sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); 489 need = 0; 490 for (mode = 0; mode < MODE_MAX; mode++) { 491 newkeys = kex->newkeys[mode]; 492 if (need < newkeys->enc.key_len) 493 need = newkeys->enc.key_len; 494 if (need < newkeys->enc.block_size) 495 need = newkeys->enc.block_size; 496 if (need < newkeys->enc.iv_len) 497 need = newkeys->enc.iv_len; 498 if (need < newkeys->mac.key_len) 499 need = newkeys->mac.key_len; 500 } 501 /* XXX need runden? */ 502 kex->we_need = need; 503 504 /* ignore the next message if the proposals do not match */ 505 if (first_kex_follows && !proposals_match(my, peer) && 506 !(datafellows & SSH_BUG_FIRSTKEX)) { 507 type = packet_read(); 508 debug2("skipping next packet (type %u)", type); 509 } 510 511 kex_prop_free(my); 512 kex_prop_free(peer); 513 } 514 515 static u_char * 516 derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen, 517 BIGNUM *shared_secret) 518 { 519 Buffer b; 520 EVP_MD_CTX md; 521 char c = id; 522 u_int have; 523 int mdsz; 524 u_char *digest; 525 526 if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0) 527 fatal("bad kex md size %d", mdsz); 528 digest = xmalloc(roundup(need, mdsz)); 529 530 buffer_init(&b); 531 buffer_put_bignum2(&b, shared_secret); 532 533 /* K1 = HASH(K || H || "A" || session_id) */ 534 EVP_DigestInit(&md, kex->evp_md); 535 if (!(datafellows & SSH_BUG_DERIVEKEY)) 536 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 537 EVP_DigestUpdate(&md, hash, hashlen); 538 EVP_DigestUpdate(&md, &c, 1); 539 EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); 540 EVP_DigestFinal(&md, digest, NULL); 541 542 /* 543 * expand key: 544 * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) 545 * Key = K1 || K2 || ... || Kn 546 */ 547 for (have = mdsz; need > have; have += mdsz) { 548 EVP_DigestInit(&md, kex->evp_md); 549 if (!(datafellows & SSH_BUG_DERIVEKEY)) 550 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 551 EVP_DigestUpdate(&md, hash, hashlen); 552 EVP_DigestUpdate(&md, digest, have); 553 EVP_DigestFinal(&md, digest + have, NULL); 554 } 555 buffer_free(&b); 556 #ifdef DEBUG_KEX 557 fprintf(stderr, "key '%c'== ", c); 558 dump_digest("key", digest, need); 559 #endif 560 return digest; 561 } 562 563 Newkeys *current_keys[MODE_MAX]; 564 565 #define NKEYS 6 566 void 567 kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret) 568 { 569 u_char *keys[NKEYS]; 570 u_int i, mode, ctos; 571 572 for (i = 0; i < NKEYS; i++) { 573 keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen, 574 shared_secret); 575 } 576 577 debug2("kex_derive_keys"); 578 for (mode = 0; mode < MODE_MAX; mode++) { 579 current_keys[mode] = kex->newkeys[mode]; 580 kex->newkeys[mode] = NULL; 581 ctos = (!kex->server && mode == MODE_OUT) || 582 (kex->server && mode == MODE_IN); 583 current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; 584 current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; 585 current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; 586 } 587 } 588 589 Newkeys * 590 kex_get_newkeys(int mode) 591 { 592 Newkeys *ret; 593 594 ret = current_keys[mode]; 595 current_keys[mode] = NULL; 596 return ret; 597 } 598 599 void 600 derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus, 601 u_int8_t cookie[8], u_int8_t id[16]) 602 { 603 const EVP_MD *evp_md = EVP_md5(); 604 EVP_MD_CTX md; 605 u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE]; 606 int len; 607 608 EVP_DigestInit(&md, evp_md); 609 610 len = BN_num_bytes(host_modulus); 611 if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) 612 fatal("%s: bad host modulus (len %d)", __func__, len); 613 BN_bn2bin(host_modulus, nbuf); 614 EVP_DigestUpdate(&md, nbuf, len); 615 616 len = BN_num_bytes(server_modulus); 617 if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) 618 fatal("%s: bad server modulus (len %d)", __func__, len); 619 BN_bn2bin(server_modulus, nbuf); 620 EVP_DigestUpdate(&md, nbuf, len); 621 622 EVP_DigestUpdate(&md, cookie, 8); 623 624 EVP_DigestFinal(&md, obuf, NULL); 625 memcpy(id, obuf, 16); 626 627 memset(nbuf, 0, sizeof(nbuf)); 628 memset(obuf, 0, sizeof(obuf)); 629 memset(&md, 0, sizeof(md)); 630 } 631 632 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 633 void 634 dump_digest(char *msg, u_char *digest, int len) 635 { 636 int i; 637 638 fprintf(stderr, "%s\n", msg); 639 for (i = 0; i < len; i++) { 640 fprintf(stderr, "%02x", digest[i]); 641 if (i%32 == 31) 642 fprintf(stderr, "\n"); 643 else if (i%8 == 7) 644 fprintf(stderr, " "); 645 } 646 fprintf(stderr, "\n"); 647 } 648 #endif 649