1 /* $OpenBSD: kex.c,v 1.99 2014/04/29 18:01:49 markus Exp $ */ 2 /* 3 * Copyright (c) 2000, 2001 Markus Friedl. 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "includes.h" 27 28 #include <sys/param.h> 29 30 #include <signal.h> 31 #include <stdarg.h> 32 #include <stdio.h> 33 #include <stdlib.h> 34 #include <string.h> 35 36 #ifdef WITH_OPENSSL 37 #include <openssl/crypto.h> 38 #endif 39 40 #include "xmalloc.h" 41 #include "ssh2.h" 42 #include "buffer.h" 43 #include "packet.h" 44 #include "compat.h" 45 #include "cipher.h" 46 #include "key.h" 47 #include "kex.h" 48 #include "log.h" 49 #include "mac.h" 50 #include "match.h" 51 #include "dispatch.h" 52 #include "monitor.h" 53 #include "roaming.h" 54 #include "digest.h" 55 56 #if OPENSSL_VERSION_NUMBER >= 0x00907000L 57 # if defined(HAVE_EVP_SHA256) 58 # define evp_ssh_sha256 EVP_sha256 59 # else 60 extern const EVP_MD *evp_ssh_sha256(void); 61 # endif 62 #endif 63 64 /* prototype */ 65 static void kex_kexinit_finish(Kex *); 66 static void kex_choose_conf(Kex *); 67 68 struct kexalg { 69 char *name; 70 int type; 71 int ec_nid; 72 int hash_alg; 73 }; 74 static const struct kexalg kexalgs[] = { 75 #ifdef WITH_OPENSSL 76 { KEX_DH1, KEX_DH_GRP1_SHA1, 0, SSH_DIGEST_SHA1 }, 77 { KEX_DH14, KEX_DH_GRP14_SHA1, 0, SSH_DIGEST_SHA1 }, 78 { KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, SSH_DIGEST_SHA1 }, 79 #ifdef HAVE_EVP_SHA256 80 { KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, SSH_DIGEST_SHA256 }, 81 #endif /* HAVE_EVP_SHA256 */ 82 #ifdef OPENSSL_HAS_ECC 83 { KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2, 84 NID_X9_62_prime256v1, SSH_DIGEST_SHA256 }, 85 { KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1, 86 SSH_DIGEST_SHA384 }, 87 # ifdef OPENSSL_HAS_NISTP521 88 { KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1, 89 SSH_DIGEST_SHA512 }, 90 # endif /* OPENSSL_HAS_NISTP521 */ 91 #endif /* OPENSSL_HAS_ECC */ 92 { KEX_DH1, KEX_DH_GRP1_SHA1, 0, SSH_DIGEST_SHA1 }, 93 #endif /* WITH_OPENSSL */ 94 #ifdef HAVE_EVP_SHA256 95 { KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 }, 96 #endif /* HAVE_EVP_SHA256 */ 97 { NULL, -1, -1, -1}, 98 }; 99 100 char * 101 kex_alg_list(char sep) 102 { 103 char *ret = NULL; 104 size_t nlen, rlen = 0; 105 const struct kexalg *k; 106 107 for (k = kexalgs; k->name != NULL; k++) { 108 if (ret != NULL) 109 ret[rlen++] = sep; 110 nlen = strlen(k->name); 111 ret = xrealloc(ret, 1, rlen + nlen + 2); 112 memcpy(ret + rlen, k->name, nlen + 1); 113 rlen += nlen; 114 } 115 return ret; 116 } 117 118 static const struct kexalg * 119 kex_alg_by_name(const char *name) 120 { 121 const struct kexalg *k; 122 123 for (k = kexalgs; k->name != NULL; k++) { 124 if (strcmp(k->name, name) == 0) 125 return k; 126 } 127 return NULL; 128 } 129 130 /* Validate KEX method name list */ 131 int 132 kex_names_valid(const char *names) 133 { 134 char *s, *cp, *p; 135 136 if (names == NULL || strcmp(names, "") == 0) 137 return 0; 138 s = cp = xstrdup(names); 139 for ((p = strsep(&cp, ",")); p && *p != '\0'; 140 (p = strsep(&cp, ","))) { 141 if (kex_alg_by_name(p) == NULL) { 142 error("Unsupported KEX algorithm \"%.100s\"", p); 143 free(s); 144 return 0; 145 } 146 } 147 debug3("kex names ok: [%s]", names); 148 free(s); 149 return 1; 150 } 151 152 /* put algorithm proposal into buffer */ 153 static void 154 kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) 155 { 156 u_int i; 157 158 buffer_clear(b); 159 /* 160 * add a dummy cookie, the cookie will be overwritten by 161 * kex_send_kexinit(), each time a kexinit is set 162 */ 163 for (i = 0; i < KEX_COOKIE_LEN; i++) 164 buffer_put_char(b, 0); 165 for (i = 0; i < PROPOSAL_MAX; i++) 166 buffer_put_cstring(b, proposal[i]); 167 buffer_put_char(b, 0); /* first_kex_packet_follows */ 168 buffer_put_int(b, 0); /* uint32 reserved */ 169 } 170 171 /* parse buffer and return algorithm proposal */ 172 static char ** 173 kex_buf2prop(Buffer *raw, int *first_kex_follows) 174 { 175 Buffer b; 176 u_int i; 177 char **proposal; 178 179 proposal = xcalloc(PROPOSAL_MAX, sizeof(char *)); 180 181 buffer_init(&b); 182 buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); 183 /* skip cookie */ 184 for (i = 0; i < KEX_COOKIE_LEN; i++) 185 buffer_get_char(&b); 186 /* extract kex init proposal strings */ 187 for (i = 0; i < PROPOSAL_MAX; i++) { 188 proposal[i] = buffer_get_cstring(&b,NULL); 189 debug2("kex_parse_kexinit: %s", proposal[i]); 190 } 191 /* first kex follows / reserved */ 192 i = buffer_get_char(&b); 193 if (first_kex_follows != NULL) 194 *first_kex_follows = i; 195 debug2("kex_parse_kexinit: first_kex_follows %d ", i); 196 i = buffer_get_int(&b); 197 debug2("kex_parse_kexinit: reserved %u ", i); 198 buffer_free(&b); 199 return proposal; 200 } 201 202 static void 203 kex_prop_free(char **proposal) 204 { 205 u_int i; 206 207 for (i = 0; i < PROPOSAL_MAX; i++) 208 free(proposal[i]); 209 free(proposal); 210 } 211 212 /* ARGSUSED */ 213 static void 214 kex_protocol_error(int type, u_int32_t seq, void *ctxt) 215 { 216 error("Hm, kex protocol error: type %d seq %u", type, seq); 217 } 218 219 static void 220 kex_reset_dispatch(void) 221 { 222 dispatch_range(SSH2_MSG_TRANSPORT_MIN, 223 SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); 224 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 225 } 226 227 void 228 kex_finish(Kex *kex) 229 { 230 kex_reset_dispatch(); 231 232 packet_start(SSH2_MSG_NEWKEYS); 233 packet_send(); 234 /* packet_write_wait(); */ 235 debug("SSH2_MSG_NEWKEYS sent"); 236 237 debug("expecting SSH2_MSG_NEWKEYS"); 238 packet_read_expect(SSH2_MSG_NEWKEYS); 239 packet_check_eom(); 240 debug("SSH2_MSG_NEWKEYS received"); 241 242 kex->done = 1; 243 buffer_clear(&kex->peer); 244 /* buffer_clear(&kex->my); */ 245 kex->flags &= ~KEX_INIT_SENT; 246 free(kex->name); 247 kex->name = NULL; 248 } 249 250 void 251 kex_send_kexinit(Kex *kex) 252 { 253 u_int32_t rnd = 0; 254 u_char *cookie; 255 u_int i; 256 257 if (kex == NULL) { 258 error("kex_send_kexinit: no kex, cannot rekey"); 259 return; 260 } 261 if (kex->flags & KEX_INIT_SENT) { 262 debug("KEX_INIT_SENT"); 263 return; 264 } 265 kex->done = 0; 266 267 /* generate a random cookie */ 268 if (buffer_len(&kex->my) < KEX_COOKIE_LEN) 269 fatal("kex_send_kexinit: kex proposal too short"); 270 cookie = buffer_ptr(&kex->my); 271 for (i = 0; i < KEX_COOKIE_LEN; i++) { 272 if (i % 4 == 0) 273 rnd = arc4random(); 274 cookie[i] = rnd; 275 rnd >>= 8; 276 } 277 packet_start(SSH2_MSG_KEXINIT); 278 packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); 279 packet_send(); 280 debug("SSH2_MSG_KEXINIT sent"); 281 kex->flags |= KEX_INIT_SENT; 282 } 283 284 /* ARGSUSED */ 285 void 286 kex_input_kexinit(int type, u_int32_t seq, void *ctxt) 287 { 288 char *ptr; 289 u_int i, dlen; 290 Kex *kex = (Kex *)ctxt; 291 292 debug("SSH2_MSG_KEXINIT received"); 293 if (kex == NULL) 294 fatal("kex_input_kexinit: no kex, cannot rekey"); 295 296 ptr = packet_get_raw(&dlen); 297 buffer_append(&kex->peer, ptr, dlen); 298 299 /* discard packet */ 300 for (i = 0; i < KEX_COOKIE_LEN; i++) 301 packet_get_char(); 302 for (i = 0; i < PROPOSAL_MAX; i++) 303 free(packet_get_string(NULL)); 304 /* 305 * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported 306 * KEX method has the server move first, but a server might be using 307 * a custom method or one that we otherwise don't support. We should 308 * be prepared to remember first_kex_follows here so we can eat a 309 * packet later. 310 * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means 311 * for cases where the server *doesn't* go first. I guess we should 312 * ignore it when it is set for these cases, which is what we do now. 313 */ 314 (void) packet_get_char(); /* first_kex_follows */ 315 (void) packet_get_int(); /* reserved */ 316 packet_check_eom(); 317 318 kex_kexinit_finish(kex); 319 } 320 321 Kex * 322 kex_setup(char *proposal[PROPOSAL_MAX]) 323 { 324 Kex *kex; 325 326 kex = xcalloc(1, sizeof(*kex)); 327 buffer_init(&kex->peer); 328 buffer_init(&kex->my); 329 kex_prop2buf(&kex->my, proposal); 330 kex->done = 0; 331 332 kex_send_kexinit(kex); /* we start */ 333 kex_reset_dispatch(); 334 335 return kex; 336 } 337 338 static void 339 kex_kexinit_finish(Kex *kex) 340 { 341 if (!(kex->flags & KEX_INIT_SENT)) 342 kex_send_kexinit(kex); 343 344 kex_choose_conf(kex); 345 346 if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX && 347 kex->kex[kex->kex_type] != NULL) { 348 (kex->kex[kex->kex_type])(kex); 349 } else { 350 fatal("Unsupported key exchange %d", kex->kex_type); 351 } 352 } 353 354 static void 355 choose_enc(Enc *enc, char *client, char *server) 356 { 357 char *name = match_list(client, server, NULL); 358 if (name == NULL) 359 fatal("no matching cipher found: client %s server %s", 360 client, server); 361 if ((enc->cipher = cipher_by_name(name)) == NULL) 362 fatal("matching cipher is not supported: %s", name); 363 enc->name = name; 364 enc->enabled = 0; 365 enc->iv = NULL; 366 enc->iv_len = cipher_ivlen(enc->cipher); 367 enc->key = NULL; 368 enc->key_len = cipher_keylen(enc->cipher); 369 enc->block_size = cipher_blocksize(enc->cipher); 370 } 371 372 static void 373 choose_mac(Mac *mac, char *client, char *server) 374 { 375 char *name = match_list(client, server, NULL); 376 if (name == NULL) 377 fatal("no matching mac found: client %s server %s", 378 client, server); 379 if (mac_setup(mac, name) < 0) 380 fatal("unsupported mac %s", name); 381 /* truncate the key */ 382 if (datafellows & SSH_BUG_HMAC) 383 mac->key_len = 16; 384 mac->name = name; 385 mac->key = NULL; 386 mac->enabled = 0; 387 } 388 389 static void 390 choose_comp(Comp *comp, char *client, char *server) 391 { 392 char *name = match_list(client, server, NULL); 393 if (name == NULL) 394 fatal("no matching comp found: client %s server %s", client, server); 395 if (strcmp(name, "zlib@openssh.com") == 0) { 396 comp->type = COMP_DELAYED; 397 } else if (strcmp(name, "zlib") == 0) { 398 comp->type = COMP_ZLIB; 399 } else if (strcmp(name, "none") == 0) { 400 comp->type = COMP_NONE; 401 } else { 402 fatal("unsupported comp %s", name); 403 } 404 comp->name = name; 405 } 406 407 static void 408 choose_kex(Kex *k, char *client, char *server) 409 { 410 const struct kexalg *kexalg; 411 412 k->name = match_list(client, server, NULL); 413 if (k->name == NULL) 414 fatal("Unable to negotiate a key exchange method"); 415 if ((kexalg = kex_alg_by_name(k->name)) == NULL) 416 fatal("unsupported kex alg %s", k->name); 417 k->kex_type = kexalg->type; 418 k->hash_alg = kexalg->hash_alg; 419 k->ec_nid = kexalg->ec_nid; 420 } 421 422 static void 423 choose_hostkeyalg(Kex *k, char *client, char *server) 424 { 425 char *hostkeyalg = match_list(client, server, NULL); 426 if (hostkeyalg == NULL) 427 fatal("no hostkey alg"); 428 k->hostkey_type = key_type_from_name(hostkeyalg); 429 if (k->hostkey_type == KEY_UNSPEC) 430 fatal("bad hostkey alg '%s'", hostkeyalg); 431 free(hostkeyalg); 432 } 433 434 static int 435 proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) 436 { 437 static int check[] = { 438 PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 439 }; 440 int *idx; 441 char *p; 442 443 for (idx = &check[0]; *idx != -1; idx++) { 444 if ((p = strchr(my[*idx], ',')) != NULL) 445 *p = '\0'; 446 if ((p = strchr(peer[*idx], ',')) != NULL) 447 *p = '\0'; 448 if (strcmp(my[*idx], peer[*idx]) != 0) { 449 debug2("proposal mismatch: my %s peer %s", 450 my[*idx], peer[*idx]); 451 return (0); 452 } 453 } 454 debug2("proposals match"); 455 return (1); 456 } 457 458 static void 459 kex_choose_conf(Kex *kex) 460 { 461 Newkeys *newkeys; 462 char **my, **peer; 463 char **cprop, **sprop; 464 int nenc, nmac, ncomp; 465 u_int mode, ctos, need, dh_need, authlen; 466 int first_kex_follows, type; 467 468 my = kex_buf2prop(&kex->my, NULL); 469 peer = kex_buf2prop(&kex->peer, &first_kex_follows); 470 471 if (kex->server) { 472 cprop=peer; 473 sprop=my; 474 } else { 475 cprop=my; 476 sprop=peer; 477 } 478 479 /* Check whether server offers roaming */ 480 if (!kex->server) { 481 char *roaming; 482 roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL); 483 if (roaming) { 484 kex->roaming = 1; 485 free(roaming); 486 } 487 } 488 489 /* Algorithm Negotiation */ 490 for (mode = 0; mode < MODE_MAX; mode++) { 491 newkeys = xcalloc(1, sizeof(*newkeys)); 492 kex->newkeys[mode] = newkeys; 493 ctos = (!kex->server && mode == MODE_OUT) || 494 (kex->server && mode == MODE_IN); 495 nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; 496 nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; 497 ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; 498 choose_enc(&newkeys->enc, cprop[nenc], sprop[nenc]); 499 /* ignore mac for authenticated encryption */ 500 authlen = cipher_authlen(newkeys->enc.cipher); 501 if (authlen == 0) 502 choose_mac(&newkeys->mac, cprop[nmac], sprop[nmac]); 503 choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); 504 debug("kex: %s %s %s %s", 505 ctos ? "client->server" : "server->client", 506 newkeys->enc.name, 507 authlen == 0 ? newkeys->mac.name : "<implicit>", 508 newkeys->comp.name); 509 } 510 choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); 511 choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], 512 sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); 513 need = dh_need = 0; 514 for (mode = 0; mode < MODE_MAX; mode++) { 515 newkeys = kex->newkeys[mode]; 516 need = MAX(need, newkeys->enc.key_len); 517 need = MAX(need, newkeys->enc.block_size); 518 need = MAX(need, newkeys->enc.iv_len); 519 need = MAX(need, newkeys->mac.key_len); 520 dh_need = MAX(dh_need, cipher_seclen(newkeys->enc.cipher)); 521 dh_need = MAX(dh_need, newkeys->enc.block_size); 522 dh_need = MAX(dh_need, newkeys->enc.iv_len); 523 dh_need = MAX(dh_need, newkeys->mac.key_len); 524 } 525 /* XXX need runden? */ 526 kex->we_need = need; 527 kex->dh_need = dh_need; 528 529 /* ignore the next message if the proposals do not match */ 530 if (first_kex_follows && !proposals_match(my, peer) && 531 !(datafellows & SSH_BUG_FIRSTKEX)) { 532 type = packet_read(); 533 debug2("skipping next packet (type %u)", type); 534 } 535 536 kex_prop_free(my); 537 kex_prop_free(peer); 538 } 539 540 static u_char * 541 derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen, 542 const u_char *shared_secret, u_int slen) 543 { 544 Buffer b; 545 struct ssh_digest_ctx *hashctx; 546 char c = id; 547 u_int have; 548 size_t mdsz; 549 u_char *digest; 550 551 if ((mdsz = ssh_digest_bytes(kex->hash_alg)) == 0) 552 fatal("bad kex md size %zu", mdsz); 553 digest = xmalloc(roundup(need, mdsz)); 554 555 buffer_init(&b); 556 buffer_append(&b, shared_secret, slen); 557 558 /* K1 = HASH(K || H || "A" || session_id) */ 559 if ((hashctx = ssh_digest_start(kex->hash_alg)) == NULL) 560 fatal("%s: ssh_digest_start failed", __func__); 561 if (ssh_digest_update_buffer(hashctx, &b) != 0 || 562 ssh_digest_update(hashctx, hash, hashlen) != 0 || 563 ssh_digest_update(hashctx, &c, 1) != 0 || 564 ssh_digest_update(hashctx, kex->session_id, 565 kex->session_id_len) != 0) 566 fatal("%s: ssh_digest_update failed", __func__); 567 if (ssh_digest_final(hashctx, digest, mdsz) != 0) 568 fatal("%s: ssh_digest_final failed", __func__); 569 ssh_digest_free(hashctx); 570 571 /* 572 * expand key: 573 * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) 574 * Key = K1 || K2 || ... || Kn 575 */ 576 for (have = mdsz; need > have; have += mdsz) { 577 if ((hashctx = ssh_digest_start(kex->hash_alg)) == NULL) 578 fatal("%s: ssh_digest_start failed", __func__); 579 if (ssh_digest_update_buffer(hashctx, &b) != 0 || 580 ssh_digest_update(hashctx, hash, hashlen) != 0 || 581 ssh_digest_update(hashctx, digest, have) != 0) 582 fatal("%s: ssh_digest_update failed", __func__); 583 if (ssh_digest_final(hashctx, digest + have, mdsz) != 0) 584 fatal("%s: ssh_digest_final failed", __func__); 585 ssh_digest_free(hashctx); 586 } 587 buffer_free(&b); 588 #ifdef DEBUG_KEX 589 fprintf(stderr, "key '%c'== ", c); 590 dump_digest("key", digest, need); 591 #endif 592 return digest; 593 } 594 595 Newkeys *current_keys[MODE_MAX]; 596 597 #define NKEYS 6 598 void 599 kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, 600 const u_char *shared_secret, u_int slen) 601 { 602 u_char *keys[NKEYS]; 603 u_int i, mode, ctos; 604 605 for (i = 0; i < NKEYS; i++) { 606 keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen, 607 shared_secret, slen); 608 } 609 610 debug2("kex_derive_keys"); 611 for (mode = 0; mode < MODE_MAX; mode++) { 612 current_keys[mode] = kex->newkeys[mode]; 613 kex->newkeys[mode] = NULL; 614 ctos = (!kex->server && mode == MODE_OUT) || 615 (kex->server && mode == MODE_IN); 616 current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; 617 current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; 618 current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; 619 } 620 } 621 622 #ifdef WITH_OPENSSL 623 void 624 kex_derive_keys_bn(Kex *kex, u_char *hash, u_int hashlen, const BIGNUM *secret) 625 { 626 Buffer shared_secret; 627 628 buffer_init(&shared_secret); 629 buffer_put_bignum2(&shared_secret, secret); 630 kex_derive_keys(kex, hash, hashlen, 631 buffer_ptr(&shared_secret), buffer_len(&shared_secret)); 632 buffer_free(&shared_secret); 633 } 634 #endif 635 636 Newkeys * 637 kex_get_newkeys(int mode) 638 { 639 Newkeys *ret; 640 641 ret = current_keys[mode]; 642 current_keys[mode] = NULL; 643 return ret; 644 } 645 646 #ifdef WITH_SSH1 647 void 648 derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus, 649 u_int8_t cookie[8], u_int8_t id[16]) 650 { 651 u_int8_t nbuf[2048], obuf[SSH_DIGEST_MAX_LENGTH]; 652 int len; 653 struct ssh_digest_ctx *hashctx; 654 655 if ((hashctx = ssh_digest_start(SSH_DIGEST_MD5)) == NULL) 656 fatal("%s: ssh_digest_start", __func__); 657 658 len = BN_num_bytes(host_modulus); 659 if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) 660 fatal("%s: bad host modulus (len %d)", __func__, len); 661 BN_bn2bin(host_modulus, nbuf); 662 if (ssh_digest_update(hashctx, nbuf, len) != 0) 663 fatal("%s: ssh_digest_update failed", __func__); 664 665 len = BN_num_bytes(server_modulus); 666 if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) 667 fatal("%s: bad server modulus (len %d)", __func__, len); 668 BN_bn2bin(server_modulus, nbuf); 669 if (ssh_digest_update(hashctx, nbuf, len) != 0 || 670 ssh_digest_update(hashctx, cookie, 8) != 0) 671 fatal("%s: ssh_digest_update failed", __func__); 672 if (ssh_digest_final(hashctx, obuf, sizeof(obuf)) != 0) 673 fatal("%s: ssh_digest_final failed", __func__); 674 memcpy(id, obuf, ssh_digest_bytes(SSH_DIGEST_MD5)); 675 676 explicit_bzero(nbuf, sizeof(nbuf)); 677 explicit_bzero(obuf, sizeof(obuf)); 678 } 679 #endif 680 681 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH) 682 void 683 dump_digest(char *msg, u_char *digest, int len) 684 { 685 int i; 686 687 fprintf(stderr, "%s\n", msg); 688 for (i = 0; i < len; i++) { 689 fprintf(stderr, "%02x", digest[i]); 690 if (i%32 == 31) 691 fprintf(stderr, "\n"); 692 else if (i%8 == 7) 693 fprintf(stderr, " "); 694 } 695 fprintf(stderr, "\n"); 696 } 697 #endif 698