1 /* 2 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23 * 24 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 25 * Use is subject to license terms. 26 */ 27 28 #include "includes.h" 29 RCSID("$OpenBSD: kex.c,v 1.51 2002/06/24 14:55:38 markus Exp $"); 30 31 #pragma ident "%Z%%M% %I% %E% SMI" 32 33 #include <locale.h> 34 35 #include <openssl/crypto.h> 36 37 #include "ssh2.h" 38 #include "xmalloc.h" 39 #include "buffer.h" 40 #include "bufaux.h" 41 #include "packet.h" 42 #include "compat.h" 43 #include "cipher.h" 44 #include "kex.h" 45 #include "key.h" 46 #include "log.h" 47 #include "mac.h" 48 #include "match.h" 49 #include "dispatch.h" 50 #include "monitor.h" 51 #include "g11n.h" 52 53 #ifdef GSSAPI 54 #include "ssh-gss.h" 55 #endif 56 57 #define KEX_COOKIE_LEN 16 58 59 /* Use privilege separation for sshd */ 60 int use_privsep; 61 struct monitor *pmonitor; 62 63 char *session_lang = NULL; 64 65 66 /* prototype */ 67 static void kex_do_hook(Kex *kex); 68 static void kex_kexinit_finish(Kex *); 69 static void kex_choose_conf(Kex *); 70 71 /* put algorithm proposal into buffer */ 72 static 73 void 74 kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) 75 { 76 int i; 77 78 buffer_clear(b); 79 /* 80 * add a dummy cookie, the cookie will be overwritten by 81 * kex_send_kexinit(), each time a kexinit is set 82 */ 83 for (i = 0; i < KEX_COOKIE_LEN; i++) 84 buffer_put_char(b, 0); 85 for (i = 0; i < PROPOSAL_MAX; i++) 86 buffer_put_cstring(b, proposal[i]); 87 buffer_put_char(b, 0); /* first_kex_packet_follows */ 88 buffer_put_int(b, 0); /* uint32 reserved */ 89 } 90 91 /* parse buffer and return algorithm proposal */ 92 static 93 char ** 94 kex_buf2prop(Buffer *raw, int *first_kex_follows) 95 { 96 Buffer b; 97 int i; 98 char **proposal; 99 100 proposal = xmalloc(PROPOSAL_MAX * sizeof(char *)); 101 102 buffer_init(&b); 103 buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); 104 /* skip cookie */ 105 for (i = 0; i < KEX_COOKIE_LEN; i++) 106 buffer_get_char(&b); 107 /* extract kex init proposal strings */ 108 for (i = 0; i < PROPOSAL_MAX; i++) { 109 proposal[i] = buffer_get_string(&b,NULL); 110 debug2("kex_parse_kexinit: %s", proposal[i]); 111 } 112 /* first kex follows / reserved */ 113 i = buffer_get_char(&b); 114 if (first_kex_follows != NULL) 115 *first_kex_follows = i; 116 debug2("kex_parse_kexinit: first_kex_follows %d ", i); 117 i = buffer_get_int(&b); 118 debug2("kex_parse_kexinit: reserved %d ", i); 119 buffer_free(&b); 120 return proposal; 121 } 122 123 static 124 void 125 kex_prop_free(char **proposal) 126 { 127 int i; 128 129 for (i = 0; i < PROPOSAL_MAX; i++) 130 xfree(proposal[i]); 131 xfree(proposal); 132 } 133 134 static void 135 kex_protocol_error(int type, u_int32_t seq, void *ctxt) 136 { 137 error("Hm, kex protocol error: type %d seq %u", type, seq); 138 } 139 140 static void 141 kex_reset_dispatch(void) 142 { 143 #ifdef ALTPRIVSEP 144 /* unprivileged sshd has a kex packet handler that must not be reset */ 145 debug3("kex_reset_dispatch -- should we dispatch_set(KEXINIT) here? %d && !%d", 146 packet_is_server(), packet_is_monitor()); 147 if (packet_is_server() && !packet_is_monitor()) { 148 debug3("kex_reset_dispatch -- skipping dispatch_set(KEXINIT) in unpriv proc"); 149 return; 150 } 151 #endif /* ALTPRIVSEP */ 152 153 dispatch_range(SSH2_MSG_TRANSPORT_MIN, 154 SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); 155 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 156 } 157 158 void 159 kex_finish(Kex *kex) 160 { 161 kex_reset_dispatch(); 162 163 packet_start(SSH2_MSG_NEWKEYS); 164 packet_send(); 165 /* packet_write_wait(); */ 166 debug("SSH2_MSG_NEWKEYS sent"); 167 168 #ifdef ALTPRIVSEP 169 if (packet_is_monitor()) 170 goto skip_newkeys; 171 #endif /* ALTPRIVSEP */ 172 debug("expecting SSH2_MSG_NEWKEYS"); 173 packet_read_expect(SSH2_MSG_NEWKEYS); 174 packet_check_eom(); 175 debug("SSH2_MSG_NEWKEYS received"); 176 #ifdef ALTPRIVSEP 177 skip_newkeys: 178 #endif /* ALTPRIVSEP */ 179 180 kex->done = 1; 181 kex->initial_kex_done = 1; /* never to be cleared once set */ 182 buffer_clear(&kex->peer); 183 /* buffer_clear(&kex->my); */ 184 kex->flags &= ~KEX_INIT_SENT; 185 #if 0 186 /* Must have this name for use in sshd (audit_save_kex())... */ 187 xfree(kex->name); 188 kex->name = NULL; 189 #endif 190 } 191 192 void 193 kex_send_kexinit(Kex *kex) 194 { 195 u_int32_t rand = 0; 196 u_char *cookie; 197 int i; 198 199 if (kex == NULL) { 200 error("kex_send_kexinit: no kex, cannot rekey"); 201 return; 202 } 203 if (kex->flags & KEX_INIT_SENT) { 204 debug("KEX_INIT_SENT"); 205 return; 206 } 207 kex->done = 0; 208 209 /* update my proposal -- e.g., add/remove GSS kexalgs */ 210 kex_do_hook(kex); 211 212 /* generate a random cookie */ 213 if (buffer_len(&kex->my) < KEX_COOKIE_LEN) 214 fatal("kex_send_kexinit: kex proposal too short"); 215 cookie = buffer_ptr(&kex->my); 216 for (i = 0; i < KEX_COOKIE_LEN; i++) { 217 if (i % 4 == 0) 218 rand = arc4random(); 219 cookie[i] = rand; 220 rand >>= 8; 221 } 222 packet_start(SSH2_MSG_KEXINIT); 223 packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); 224 packet_send(); 225 debug("SSH2_MSG_KEXINIT sent"); 226 kex->flags |= KEX_INIT_SENT; 227 } 228 229 void 230 kex_input_kexinit(int type, u_int32_t seq, void *ctxt) 231 { 232 char *ptr; 233 u_int dlen; 234 int i; 235 Kex *kex = (Kex *)ctxt; 236 237 debug("SSH2_MSG_KEXINIT received"); 238 if (kex == NULL) 239 fatal("kex_input_kexinit: no kex, cannot rekey"); 240 241 ptr = packet_get_raw(&dlen); 242 buffer_append(&kex->peer, ptr, dlen); 243 244 /* discard packet */ 245 for (i = 0; i < KEX_COOKIE_LEN; i++) 246 packet_get_char(); 247 for (i = 0; i < PROPOSAL_MAX; i++) 248 xfree(packet_get_string(NULL)); 249 (void) packet_get_char(); 250 (void) packet_get_int(); 251 packet_check_eom(); 252 253 kex_kexinit_finish(kex); 254 } 255 256 /* 257 * This is for GSS keyex, where actual KEX offer can change at rekey 258 * time due to credential expiration/renewal... 259 */ 260 static 261 void 262 kex_do_hook(Kex *kex) 263 { 264 char **prop; 265 266 if (kex->kex_hook == NULL) 267 return; 268 269 /* Unmarshall my proposal, let the hook modify it, remarshall it */ 270 prop = kex_buf2prop(&kex->my, NULL); 271 buffer_clear(&kex->my); 272 (kex->kex_hook)(kex, prop); 273 kex_prop2buf(&kex->my, prop); 274 kex_prop_free(prop); 275 } 276 277 Kex * 278 kex_setup(const char *host, char *proposal[PROPOSAL_MAX], Kex_hook_func hook) 279 { 280 Kex *kex; 281 282 kex = xmalloc(sizeof(*kex)); 283 memset(kex, 0, sizeof(*kex)); 284 buffer_init(&kex->peer); 285 buffer_init(&kex->my); 286 287 kex->kex_hook = hook; /* called by kex_send_kexinit() */ 288 289 if (host != NULL && *host != '\0') 290 kex->serverhost = xstrdup(host); 291 else 292 kex->server = 1; 293 294 kex_prop2buf(&kex->my, proposal); 295 296 kex_send_kexinit(kex); 297 kex_reset_dispatch(); 298 299 return kex; 300 } 301 302 static void 303 kex_kexinit_finish(Kex *kex) 304 { 305 if (!(kex->flags & KEX_INIT_SENT)) 306 kex_send_kexinit(kex); 307 308 kex_choose_conf(kex); 309 310 if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX && 311 kex->kex[kex->kex_type] != NULL) 312 (kex->kex[kex->kex_type])(kex); 313 else 314 fatal("Unsupported key exchange %d", kex->kex_type); 315 } 316 317 static void 318 choose_lang(char **lang, char *client, char *server) 319 { 320 if (datafellows & SSH_BUG_LOCALES_NOT_LANGTAGS) 321 *lang = match_list(client, server, NULL); 322 else 323 *lang = g11n_srvr_locale_negotiate(client, NULL); 324 } 325 static void 326 choose_enc(Enc *enc, char *client, char *server) 327 { 328 char *name = match_list(client, server, NULL); 329 if (name == NULL) 330 fatal("no matching cipher found: client %s server %s", client, server); 331 if ((enc->cipher = cipher_by_name(name)) == NULL) 332 fatal("matching cipher is not supported: %s", name); 333 enc->name = name; 334 enc->enabled = 0; 335 enc->iv = NULL; 336 enc->key = NULL; 337 enc->key_len = cipher_keylen(enc->cipher); 338 enc->block_size = cipher_blocksize(enc->cipher); 339 } 340 static void 341 choose_mac(Mac *mac, char *client, char *server) 342 { 343 char *name = match_list(client, server, NULL); 344 if (name == NULL) 345 fatal("no matching mac found: client %s server %s", client, server); 346 if (mac_init(mac, name) < 0) 347 fatal("unsupported mac %s", name); 348 /* truncate the key */ 349 if (datafellows & SSH_BUG_HMAC) 350 mac->key_len = 16; 351 mac->name = name; 352 mac->key = NULL; 353 mac->enabled = 0; 354 } 355 static void 356 choose_comp(Comp *comp, char *client, char *server) 357 { 358 char *name = match_list(client, server, NULL); 359 if (name == NULL) 360 fatal("no matching comp found: client %s server %s", client, server); 361 if (strcmp(name, "zlib") == 0) { 362 comp->type = 1; 363 } else if (strcmp(name, "none") == 0) { 364 comp->type = 0; 365 } else { 366 fatal("unsupported comp %s", name); 367 } 368 comp->name = name; 369 } 370 static void 371 choose_kex(Kex *k, char *client, char *server) 372 { 373 k->name = match_list(client, server, NULL); 374 if (k->name == NULL) 375 fatal("no kex alg"); 376 /* XXX Finish 3.6/7 merge of kex stuff -- choose_kex() done */ 377 if (strcmp(k->name, KEX_DH1) == 0) { 378 k->kex_type = KEX_DH_GRP1_SHA1; 379 } else if (strcmp(k->name, KEX_DHGEX) == 0) { 380 k->kex_type = KEX_DH_GEX_SHA1; 381 #ifdef GSSAPI 382 } else if (strncmp(k->name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) == 0) { 383 k->kex_type = KEX_GSS_GRP1_SHA1; 384 #endif 385 } else 386 fatal("bad kex alg %s", k->name); 387 } 388 static void 389 choose_hostkeyalg(Kex *k, char *client, char *server) 390 { 391 char *hostkeyalg = match_list(client, server, NULL); 392 if (hostkeyalg == NULL) 393 fatal("no hostkey alg"); 394 k->hostkey_type = key_type_from_name(hostkeyalg); 395 if (k->hostkey_type == KEY_UNSPEC) 396 fatal("bad hostkey alg '%s'", hostkeyalg); 397 xfree(hostkeyalg); 398 } 399 400 static int 401 proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) 402 { 403 static int check[] = { 404 PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 405 }; 406 int *idx; 407 char *p; 408 409 for (idx = &check[0]; *idx != -1; idx++) { 410 if ((p = strchr(my[*idx], ',')) != NULL) 411 *p = '\0'; 412 if ((p = strchr(peer[*idx], ',')) != NULL) 413 *p = '\0'; 414 if (strcmp(my[*idx], peer[*idx]) != 0) { 415 debug2("proposal mismatch: my %s peer %s", 416 my[*idx], peer[*idx]); 417 return (0); 418 } 419 } 420 debug2("proposals match"); 421 return (1); 422 } 423 424 static void 425 kex_choose_conf(Kex *kex) 426 { 427 Newkeys *newkeys; 428 char **my, **peer; 429 char **cprop, **sprop; 430 char *p_langs_c2s, *p_langs_s2c; /* peer's langs */ 431 char *plangs = NULL; /* peer's langs*/ 432 char *mlangs = NULL; /* my langs */ 433 int nenc, nmac, ncomp; 434 int mode; 435 int ctos; /* direction: if true client-to-server */ 436 int need; 437 int first_kex_follows, type; 438 439 my = kex_buf2prop(&kex->my, NULL); 440 peer = kex_buf2prop(&kex->peer, &first_kex_follows); 441 442 if (kex->server) { 443 cprop=peer; 444 sprop=my; 445 } else { 446 cprop=my; 447 sprop=peer; 448 } 449 450 /* Algorithm Negotiation */ 451 for (mode = 0; mode < MODE_MAX; mode++) { 452 newkeys = xmalloc(sizeof(*newkeys)); 453 memset(newkeys, 0, sizeof(*newkeys)); 454 kex->newkeys[mode] = newkeys; 455 ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); 456 nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; 457 nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; 458 ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; 459 choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]); 460 choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]); 461 choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); 462 debug("kex: %s %s %s %s", 463 ctos ? "client->server" : "server->client", 464 newkeys->enc.name, 465 newkeys->mac.name, 466 newkeys->comp.name); 467 } 468 choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); 469 choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], 470 sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); 471 need = 0; 472 for (mode = 0; mode < MODE_MAX; mode++) { 473 newkeys = kex->newkeys[mode]; 474 if (need < newkeys->enc.key_len) 475 need = newkeys->enc.key_len; 476 if (need < newkeys->enc.block_size) 477 need = newkeys->enc.block_size; 478 if (need < newkeys->mac.key_len) 479 need = newkeys->mac.key_len; 480 } 481 /* XXX need runden? */ 482 kex->we_need = need; 483 484 /* ignore the next message if the proposals do not match */ 485 if (first_kex_follows && !proposals_match(my, peer) && 486 !(datafellows & SSH_BUG_FIRSTKEX)) { 487 type = packet_read(); 488 debug2("skipping next packet (type %u)", type); 489 } 490 491 /* Language/locale negotiation -- not worth doing on re-key */ 492 493 if (!kex->initial_kex_done) { 494 p_langs_c2s = peer[PROPOSAL_LANG_CTOS]; 495 p_langs_s2c = peer[PROPOSAL_LANG_STOC]; 496 debug("Peer sent proposed langtags, ctos: %s", p_langs_c2s); 497 debug("Peer sent proposed langtags, stoc: %s", p_langs_s2c); 498 plangs = NULL; 499 500 /* We propose the same langs for each protocol direction */ 501 mlangs = my[PROPOSAL_LANG_STOC]; 502 debug("We proposed langtags, ctos: %s", my[PROPOSAL_LANG_CTOS]); 503 debug("We proposed langtags, stoc: %s", mlangs); 504 505 /* 506 * Why oh why did they bother with negotiating langs for 507 * each protocol direction?! 508 * 509 * The semantics of this are vaguely specified, but one can 510 * imagine using one language (locale) for the whole session and 511 * a different one for message localization (e.g., 'en_US.UTF-8' 512 * overall and 'fr' for messages). Weird? Maybe. But lang 513 * tags don't include codeset info, like locales do... 514 * 515 * So, server-side we want: 516 * - setlocale(LC_ALL, c2s_locale); 517 * and 518 * - setlocale(LC_MESSAGES, s2c_locale); 519 * 520 * Client-side we don't really care. But we could do: 521 * 522 * - when very verbose, tell the use what lang the server's 523 * messages are in, if left out in the protocol 524 * - when sending messages to the server, and if applicable, we 525 * can localize them according to the language negotiated for 526 * that direction. 527 * 528 * But for now we do nothing on the client side. 529 */ 530 if ((p_langs_c2s && *p_langs_c2s) && !(p_langs_s2c && *p_langs_s2c)) 531 plangs = p_langs_c2s; 532 else if ((p_langs_s2c && *p_langs_s2c) && !(p_langs_c2s && *p_langs_c2s)) 533 plangs = p_langs_s2c; 534 else 535 plangs = p_langs_c2s; 536 537 if (kex->server) { 538 if (plangs && mlangs && *plangs && *mlangs) { 539 char *locale; 540 541 choose_lang(&locale, plangs, mlangs); 542 if (locale) { 543 g11n_setlocale(LC_ALL, locale); 544 debug("Negotiated main locale: %s", locale); 545 packet_send_debug("Negotiated main locale: %s", locale); 546 } 547 if (plangs != p_langs_s2c && 548 p_langs_s2c && *p_langs_s2c) { 549 choose_lang(&locale, p_langs_s2c, mlangs); 550 if (locale) { 551 g11n_setlocale(LC_MESSAGES, locale); 552 debug("Negotiated messages locale: %s", locale); 553 packet_send_debug("Negotiated messages locale: %s", locale); 554 } 555 } 556 /* 557 * Should we free locale? Or does setlocale 558 * retain a reference? 559 */ 560 /*xfree(locale);*/ 561 } 562 } 563 else { 564 if (plangs && mlangs && *plangs && *mlangs && 565 !(datafellows & SSH_BUG_LOCALES_NOT_LANGTAGS)) { 566 char *lang; 567 lang = g11n_clnt_langtag_negotiate(mlangs, plangs); 568 if (lang) { 569 session_lang = lang; 570 debug("Negotiated lang: %s", lang); 571 } 572 } 573 } 574 } 575 576 kex_prop_free(my); 577 kex_prop_free(peer); 578 } 579 580 static u_char * 581 derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret) 582 { 583 Buffer b; 584 const EVP_MD *evp_md = EVP_sha1(); 585 EVP_MD_CTX md; 586 char c = id; 587 int have; 588 int mdsz = EVP_MD_size(evp_md); 589 u_char *digest = xmalloc(roundup(need, mdsz)); 590 591 buffer_init(&b); 592 buffer_put_bignum2(&b, shared_secret); 593 594 /* K1 = HASH(K || H || "A" || session_id) */ 595 EVP_DigestInit(&md, evp_md); 596 if (!(datafellows & SSH_BUG_DERIVEKEY)) 597 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 598 EVP_DigestUpdate(&md, hash, mdsz); 599 EVP_DigestUpdate(&md, &c, 1); 600 EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); 601 EVP_DigestFinal(&md, digest, NULL); 602 603 /* 604 * expand key: 605 * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) 606 * Key = K1 || K2 || ... || Kn 607 */ 608 for (have = mdsz; need > have; have += mdsz) { 609 EVP_DigestInit(&md, evp_md); 610 if (!(datafellows & SSH_BUG_DERIVEKEY)) 611 EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); 612 EVP_DigestUpdate(&md, hash, mdsz); 613 EVP_DigestUpdate(&md, digest, have); 614 EVP_DigestFinal(&md, digest + have, NULL); 615 } 616 buffer_free(&b); 617 #ifdef DEBUG_KEX 618 fprintf(stderr, "key '%c'== ", c); 619 dump_digest("key", digest, need); 620 #endif 621 return digest; 622 } 623 624 Newkeys *current_keys[MODE_MAX]; 625 626 #define NKEYS 6 627 void 628 kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) 629 { 630 u_char *keys[NKEYS]; 631 int i, mode, ctos; 632 633 for (i = 0; i < NKEYS; i++) 634 keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret); 635 636 debug2("kex_derive_keys"); 637 for (mode = 0; mode < MODE_MAX; mode++) { 638 current_keys[mode] = kex->newkeys[mode]; 639 kex->newkeys[mode] = NULL; 640 ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); 641 current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; 642 current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; 643 current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; 644 } 645 } 646 647 Newkeys * 648 kex_get_newkeys(int mode) 649 { 650 Newkeys *ret; 651 652 ret = current_keys[mode]; 653 current_keys[mode] = NULL; 654 return ret; 655 } 656 657 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) 658 void 659 dump_digest(char *msg, u_char *digest, int len) 660 { 661 int i; 662 663 fprintf(stderr, "%s\n", msg); 664 for (i = 0; i< len; i++) { 665 fprintf(stderr, "%02x", digest[i]); 666 if (i%32 == 31) 667 fprintf(stderr, "\n"); 668 else if (i%8 == 7) 669 fprintf(stderr, " "); 670 } 671 fprintf(stderr, "\n"); 672 } 673 #endif 674