1 /* $OpenBSD: kex.c,v 1.109 2015/07/30 00:01:34 djm Exp $ */
3 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
28 #include <sys/param.h> /* MAX roundup */
37 #include <openssl/crypto.h>
58 #if OPENSSL_VERSION_NUMBER >= 0x00907000L
59 # if defined(HAVE_EVP_SHA256)
60 # define evp_ssh_sha256 EVP_sha256
62 extern const EVP_MD *evp_ssh_sha256(void);
67 static int kex_choose_conf(struct ssh *);
68 static int kex_input_newkeys(int, u_int32_t, void *);
76 static const struct kexalg kexalgs[] = {
78 { KEX_DH1, KEX_DH_GRP1_SHA1, 0, SSH_DIGEST_SHA1 },
79 { KEX_DH14, KEX_DH_GRP14_SHA1, 0, SSH_DIGEST_SHA1 },
80 { KEX_DHGEX_SHA1, KEX_DH_GEX_SHA1, 0, SSH_DIGEST_SHA1 },
81 #ifdef HAVE_EVP_SHA256
82 { KEX_DHGEX_SHA256, KEX_DH_GEX_SHA256, 0, SSH_DIGEST_SHA256 },
83 #endif /* HAVE_EVP_SHA256 */
84 #ifdef OPENSSL_HAS_ECC
85 { KEX_ECDH_SHA2_NISTP256, KEX_ECDH_SHA2,
86 NID_X9_62_prime256v1, SSH_DIGEST_SHA256 },
87 { KEX_ECDH_SHA2_NISTP384, KEX_ECDH_SHA2, NID_secp384r1,
89 # ifdef OPENSSL_HAS_NISTP521
90 { KEX_ECDH_SHA2_NISTP521, KEX_ECDH_SHA2, NID_secp521r1,
92 # endif /* OPENSSL_HAS_NISTP521 */
93 #endif /* OPENSSL_HAS_ECC */
94 #endif /* WITH_OPENSSL */
95 #if defined(HAVE_EVP_SHA256) || !defined(WITH_OPENSSL)
96 { KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
97 #endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
102 kex_alg_list(char sep)
104 char *ret = NULL, *tmp;
105 size_t nlen, rlen = 0;
106 const struct kexalg *k;
108 for (k = kexalgs; k->name != NULL; k++) {
111 nlen = strlen(k->name);
112 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
117 memcpy(ret + rlen, k->name, nlen + 1);
123 static const struct kexalg *
124 kex_alg_by_name(const char *name)
126 const struct kexalg *k;
128 for (k = kexalgs; k->name != NULL; k++) {
129 if (strcmp(k->name, name) == 0)
135 /* Validate KEX method name list */
137 kex_names_valid(const char *names)
141 if (names == NULL || strcmp(names, "") == 0)
143 if ((s = cp = strdup(names)) == NULL)
145 for ((p = strsep(&cp, ",")); p && *p != '\0';
146 (p = strsep(&cp, ","))) {
147 if (kex_alg_by_name(p) == NULL) {
148 error("Unsupported KEX algorithm \"%.100s\"", p);
153 debug3("kex names ok: [%s]", names);
159 * Concatenate algorithm names, avoiding duplicates in the process.
160 * Caller must free returned string.
163 kex_names_cat(const char *a, const char *b)
165 char *ret = NULL, *tmp = NULL, *cp, *p;
168 if (a == NULL || *a == '\0')
170 if (b == NULL || *b == '\0')
172 if (strlen(b) > 1024*1024)
174 len = strlen(a) + strlen(b) + 2;
175 if ((tmp = cp = strdup(b)) == NULL ||
176 (ret = calloc(1, len)) == NULL) {
180 strlcpy(ret, a, len);
181 for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) {
182 if (match_list(ret, p, NULL) != NULL)
183 continue; /* Algorithm already present */
184 if (strlcat(ret, ",", len) >= len ||
185 strlcat(ret, p, len) >= len) {
188 return NULL; /* Shouldn't happen */
196 * Assemble a list of algorithms from a default list and a string from a
197 * configuration file. The user-provided string may begin with '+' to
198 * indicate that it should be appended to the default.
201 kex_assemble_names(const char *def, char **list)
205 if (list == NULL || *list == NULL || **list == '\0') {
213 if ((ret = kex_names_cat(def, *list + 1)) == NULL)
214 return SSH_ERR_ALLOC_FAIL;
220 /* put algorithm proposal into buffer */
222 kex_prop2buf(struct sshbuf *b, char *proposal[PROPOSAL_MAX])
230 * add a dummy cookie, the cookie will be overwritten by
231 * kex_send_kexinit(), each time a kexinit is set
233 for (i = 0; i < KEX_COOKIE_LEN; i++) {
234 if ((r = sshbuf_put_u8(b, 0)) != 0)
237 for (i = 0; i < PROPOSAL_MAX; i++) {
238 if ((r = sshbuf_put_cstring(b, proposal[i])) != 0)
241 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* first_kex_packet_follows */
242 (r = sshbuf_put_u32(b, 0)) != 0) /* uint32 reserved */
247 /* parse buffer and return algorithm proposal */
249 kex_buf2prop(struct sshbuf *raw, int *first_kex_follows, char ***propp)
251 struct sshbuf *b = NULL;
254 char **proposal = NULL;
258 if ((proposal = calloc(PROPOSAL_MAX, sizeof(char *))) == NULL)
259 return SSH_ERR_ALLOC_FAIL;
260 if ((b = sshbuf_fromb(raw)) == NULL) {
261 r = SSH_ERR_ALLOC_FAIL;
264 if ((r = sshbuf_consume(b, KEX_COOKIE_LEN)) != 0) /* skip cookie */
266 /* extract kex init proposal strings */
267 for (i = 0; i < PROPOSAL_MAX; i++) {
268 if ((r = sshbuf_get_cstring(b, &(proposal[i]), NULL)) != 0)
270 debug2("kex_parse_kexinit: %s", proposal[i]);
272 /* first kex follows / reserved */
273 if ((r = sshbuf_get_u8(b, &v)) != 0 || /* first_kex_follows */
274 (r = sshbuf_get_u32(b, &i)) != 0) /* reserved */
276 if (first_kex_follows != NULL)
277 *first_kex_follows = v;
278 debug2("first_kex_follows %d ", v);
279 debug2("reserved %u ", i);
283 if (r != 0 && proposal != NULL)
284 kex_prop_free(proposal);
290 kex_prop_free(char **proposal)
294 if (proposal == NULL)
296 for (i = 0; i < PROPOSAL_MAX; i++)
303 kex_protocol_error(int type, u_int32_t seq, void *ctxt)
305 error("Hm, kex protocol error: type %d seq %u", type, seq);
310 kex_reset_dispatch(struct ssh *ssh)
312 ssh_dispatch_range(ssh, SSH2_MSG_TRANSPORT_MIN,
313 SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
314 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit);
318 kex_send_newkeys(struct ssh *ssh)
322 kex_reset_dispatch(ssh);
323 if ((r = sshpkt_start(ssh, SSH2_MSG_NEWKEYS)) != 0 ||
324 (r = sshpkt_send(ssh)) != 0)
326 debug("SSH2_MSG_NEWKEYS sent");
327 debug("expecting SSH2_MSG_NEWKEYS");
328 ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
333 kex_input_newkeys(int type, u_int32_t seq, void *ctxt)
335 struct ssh *ssh = ctxt;
336 struct kex *kex = ssh->kex;
339 debug("SSH2_MSG_NEWKEYS received");
340 ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_protocol_error);
341 if ((r = sshpkt_get_end(ssh)) != 0)
344 sshbuf_reset(kex->peer);
345 /* sshbuf_reset(kex->my); */
346 kex->flags &= ~KEX_INIT_SENT;
353 kex_send_kexinit(struct ssh *ssh)
356 struct kex *kex = ssh->kex;
360 return SSH_ERR_INTERNAL_ERROR;
361 if (kex->flags & KEX_INIT_SENT)
365 /* generate a random cookie */
366 if (sshbuf_len(kex->my) < KEX_COOKIE_LEN)
367 return SSH_ERR_INVALID_FORMAT;
368 if ((cookie = sshbuf_mutable_ptr(kex->my)) == NULL)
369 return SSH_ERR_INTERNAL_ERROR;
370 arc4random_buf(cookie, KEX_COOKIE_LEN);
372 if ((r = sshpkt_start(ssh, SSH2_MSG_KEXINIT)) != 0 ||
373 (r = sshpkt_putb(ssh, kex->my)) != 0 ||
374 (r = sshpkt_send(ssh)) != 0)
376 debug("SSH2_MSG_KEXINIT sent");
377 kex->flags |= KEX_INIT_SENT;
383 kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
385 struct ssh *ssh = ctxt;
386 struct kex *kex = ssh->kex;
392 debug("SSH2_MSG_KEXINIT received");
394 return SSH_ERR_INVALID_ARGUMENT;
396 ptr = sshpkt_ptr(ssh, &dlen);
397 if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
401 for (i = 0; i < KEX_COOKIE_LEN; i++)
402 if ((r = sshpkt_get_u8(ssh, NULL)) != 0)
404 for (i = 0; i < PROPOSAL_MAX; i++)
405 if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0)
408 * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported
409 * KEX method has the server move first, but a server might be using
410 * a custom method or one that we otherwise don't support. We should
411 * be prepared to remember first_kex_follows here so we can eat a
413 * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means
414 * for cases where the server *doesn't* go first. I guess we should
415 * ignore it when it is set for these cases, which is what we do now.
417 if ((r = sshpkt_get_u8(ssh, NULL)) != 0 || /* first_kex_follows */
418 (r = sshpkt_get_u32(ssh, NULL)) != 0 || /* reserved */
419 (r = sshpkt_get_end(ssh)) != 0)
422 if (!(kex->flags & KEX_INIT_SENT))
423 if ((r = kex_send_kexinit(ssh)) != 0)
425 if ((r = kex_choose_conf(ssh)) != 0)
428 if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)
429 return (kex->kex[kex->kex_type])(ssh);
431 return SSH_ERR_INTERNAL_ERROR;
435 kex_new(struct ssh *ssh, char *proposal[PROPOSAL_MAX], struct kex **kexp)
441 if ((kex = calloc(1, sizeof(*kex))) == NULL)
442 return SSH_ERR_ALLOC_FAIL;
443 if ((kex->peer = sshbuf_new()) == NULL ||
444 (kex->my = sshbuf_new()) == NULL) {
445 r = SSH_ERR_ALLOC_FAIL;
448 if ((r = kex_prop2buf(kex->my, proposal)) != 0)
451 kex_reset_dispatch(ssh);
461 kex_free_newkeys(struct newkeys *newkeys)
465 if (newkeys->enc.key) {
466 explicit_bzero(newkeys->enc.key, newkeys->enc.key_len);
467 free(newkeys->enc.key);
468 newkeys->enc.key = NULL;
470 if (newkeys->enc.iv) {
471 explicit_bzero(newkeys->enc.iv, newkeys->enc.block_size);
472 free(newkeys->enc.iv);
473 newkeys->enc.iv = NULL;
475 free(newkeys->enc.name);
476 explicit_bzero(&newkeys->enc, sizeof(newkeys->enc));
477 free(newkeys->comp.name);
478 explicit_bzero(&newkeys->comp, sizeof(newkeys->comp));
479 mac_clear(&newkeys->mac);
480 if (newkeys->mac.key) {
481 explicit_bzero(newkeys->mac.key, newkeys->mac.key_len);
482 free(newkeys->mac.key);
483 newkeys->mac.key = NULL;
485 free(newkeys->mac.name);
486 explicit_bzero(&newkeys->mac, sizeof(newkeys->mac));
487 explicit_bzero(newkeys, sizeof(*newkeys));
492 kex_free(struct kex *kex)
499 #ifdef OPENSSL_HAS_ECC
500 if (kex->ec_client_key)
501 EC_KEY_free(kex->ec_client_key);
502 #endif /* OPENSSL_HAS_ECC */
503 #endif /* WITH_OPENSSL */
504 for (mode = 0; mode < MODE_MAX; mode++) {
505 kex_free_newkeys(kex->newkeys[mode]);
506 kex->newkeys[mode] = NULL;
508 sshbuf_free(kex->peer);
509 sshbuf_free(kex->my);
510 free(kex->session_id);
511 free(kex->client_version_string);
512 free(kex->server_version_string);
513 free(kex->failed_choice);
518 kex_setup(struct ssh *ssh, char *proposal[PROPOSAL_MAX])
522 if ((r = kex_new(ssh, proposal, &ssh->kex)) != 0)
524 if ((r = kex_send_kexinit(ssh)) != 0) { /* we start */
533 choose_enc(struct sshenc *enc, char *client, char *server)
535 char *name = match_list(client, server, NULL);
538 return SSH_ERR_NO_CIPHER_ALG_MATCH;
539 if ((enc->cipher = cipher_by_name(name)) == NULL)
540 return SSH_ERR_INTERNAL_ERROR;
544 enc->iv_len = cipher_ivlen(enc->cipher);
546 enc->key_len = cipher_keylen(enc->cipher);
547 enc->block_size = cipher_blocksize(enc->cipher);
552 choose_mac(struct ssh *ssh, struct sshmac *mac, char *client, char *server)
554 char *name = match_list(client, server, NULL);
557 return SSH_ERR_NO_MAC_ALG_MATCH;
558 if (mac_setup(mac, name) < 0)
559 return SSH_ERR_INTERNAL_ERROR;
560 /* truncate the key */
561 if (ssh->compat & SSH_BUG_HMAC)
570 choose_comp(struct sshcomp *comp, char *client, char *server)
572 char *name = match_list(client, server, NULL);
575 return SSH_ERR_NO_COMPRESS_ALG_MATCH;
576 if (strcmp(name, "zlib@openssh.com") == 0) {
577 comp->type = COMP_DELAYED;
578 } else if (strcmp(name, "zlib") == 0) {
579 comp->type = COMP_ZLIB;
580 } else if (strcmp(name, "none") == 0) {
581 comp->type = COMP_NONE;
583 return SSH_ERR_INTERNAL_ERROR;
590 choose_kex(struct kex *k, char *client, char *server)
592 const struct kexalg *kexalg;
594 k->name = match_list(client, server, NULL);
597 return SSH_ERR_NO_KEX_ALG_MATCH;
598 if ((kexalg = kex_alg_by_name(k->name)) == NULL)
599 return SSH_ERR_INTERNAL_ERROR;
600 k->kex_type = kexalg->type;
601 k->hash_alg = kexalg->hash_alg;
602 k->ec_nid = kexalg->ec_nid;
607 choose_hostkeyalg(struct kex *k, char *client, char *server)
609 char *hostkeyalg = match_list(client, server, NULL);
611 if (hostkeyalg == NULL)
612 return SSH_ERR_NO_HOSTKEY_ALG_MATCH;
613 k->hostkey_type = sshkey_type_from_name(hostkeyalg);
614 if (k->hostkey_type == KEY_UNSPEC)
615 return SSH_ERR_INTERNAL_ERROR;
616 k->hostkey_nid = sshkey_ecdsa_nid_from_name(hostkeyalg);
622 proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
624 static int check[] = {
625 PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
630 for (idx = &check[0]; *idx != -1; idx++) {
631 if ((p = strchr(my[*idx], ',')) != NULL)
633 if ((p = strchr(peer[*idx], ',')) != NULL)
635 if (strcmp(my[*idx], peer[*idx]) != 0) {
636 debug2("proposal mismatch: my %s peer %s",
637 my[*idx], peer[*idx]);
641 debug2("proposals match");
646 kex_choose_conf(struct ssh *ssh)
648 struct kex *kex = ssh->kex;
649 struct newkeys *newkeys;
650 char **my = NULL, **peer = NULL;
651 char **cprop, **sprop;
652 int nenc, nmac, ncomp;
653 u_int mode, ctos, need, dh_need, authlen;
654 int r, first_kex_follows;
656 if ((r = kex_buf2prop(kex->my, NULL, &my)) != 0 ||
657 (r = kex_buf2prop(kex->peer, &first_kex_follows, &peer)) != 0)
668 /* Check whether server offers roaming */
670 char *roaming = match_list(KEX_RESUME,
671 peer[PROPOSAL_KEX_ALGS], NULL);
679 /* Algorithm Negotiation */
680 for (mode = 0; mode < MODE_MAX; mode++) {
681 if ((newkeys = calloc(1, sizeof(*newkeys))) == NULL) {
682 r = SSH_ERR_ALLOC_FAIL;
685 kex->newkeys[mode] = newkeys;
686 ctos = (!kex->server && mode == MODE_OUT) ||
687 (kex->server && mode == MODE_IN);
688 nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
689 nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
690 ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
691 if ((r = choose_enc(&newkeys->enc, cprop[nenc],
692 sprop[nenc])) != 0) {
693 kex->failed_choice = peer[nenc];
697 authlen = cipher_authlen(newkeys->enc.cipher);
698 /* ignore mac for authenticated encryption */
700 (r = choose_mac(ssh, &newkeys->mac, cprop[nmac],
701 sprop[nmac])) != 0) {
702 kex->failed_choice = peer[nmac];
706 if ((r = choose_comp(&newkeys->comp, cprop[ncomp],
707 sprop[ncomp])) != 0) {
708 kex->failed_choice = peer[ncomp];
712 debug("kex: %s %s %s %s",
713 ctos ? "client->server" : "server->client",
715 authlen == 0 ? newkeys->mac.name : "<implicit>",
718 if ((r = choose_kex(kex, cprop[PROPOSAL_KEX_ALGS],
719 sprop[PROPOSAL_KEX_ALGS])) != 0) {
720 kex->failed_choice = peer[PROPOSAL_KEX_ALGS];
721 peer[PROPOSAL_KEX_ALGS] = NULL;
724 if ((r = choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
725 sprop[PROPOSAL_SERVER_HOST_KEY_ALGS])) != 0) {
726 kex->failed_choice = peer[PROPOSAL_SERVER_HOST_KEY_ALGS];
727 peer[PROPOSAL_SERVER_HOST_KEY_ALGS] = NULL;
731 for (mode = 0; mode < MODE_MAX; mode++) {
732 newkeys = kex->newkeys[mode];
733 need = MAX(need, newkeys->enc.key_len);
734 need = MAX(need, newkeys->enc.block_size);
735 need = MAX(need, newkeys->enc.iv_len);
736 need = MAX(need, newkeys->mac.key_len);
737 dh_need = MAX(dh_need, cipher_seclen(newkeys->enc.cipher));
738 dh_need = MAX(dh_need, newkeys->enc.block_size);
739 dh_need = MAX(dh_need, newkeys->enc.iv_len);
740 dh_need = MAX(dh_need, newkeys->mac.key_len);
742 /* XXX need runden? */
744 kex->dh_need = dh_need;
746 /* ignore the next message if the proposals do not match */
747 if (first_kex_follows && !proposals_match(my, peer) &&
748 !(ssh->compat & SSH_BUG_FIRSTKEX))
749 ssh->dispatch_skip_packets = 1;
758 derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,
759 const struct sshbuf *shared_secret, u_char **keyp)
761 struct kex *kex = ssh->kex;
762 struct ssh_digest_ctx *hashctx = NULL;
769 if ((mdsz = ssh_digest_bytes(kex->hash_alg)) == 0)
770 return SSH_ERR_INVALID_ARGUMENT;
771 if ((digest = calloc(1, roundup(need, mdsz))) == NULL) {
772 r = SSH_ERR_ALLOC_FAIL;
776 /* K1 = HASH(K || H || "A" || session_id) */
777 if ((hashctx = ssh_digest_start(kex->hash_alg)) == NULL ||
778 ssh_digest_update_buffer(hashctx, shared_secret) != 0 ||
779 ssh_digest_update(hashctx, hash, hashlen) != 0 ||
780 ssh_digest_update(hashctx, &c, 1) != 0 ||
781 ssh_digest_update(hashctx, kex->session_id,
782 kex->session_id_len) != 0 ||
783 ssh_digest_final(hashctx, digest, mdsz) != 0) {
784 r = SSH_ERR_LIBCRYPTO_ERROR;
787 ssh_digest_free(hashctx);
792 * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
793 * Key = K1 || K2 || ... || Kn
795 for (have = mdsz; need > have; have += mdsz) {
796 if ((hashctx = ssh_digest_start(kex->hash_alg)) == NULL ||
797 ssh_digest_update_buffer(hashctx, shared_secret) != 0 ||
798 ssh_digest_update(hashctx, hash, hashlen) != 0 ||
799 ssh_digest_update(hashctx, digest, have) != 0 ||
800 ssh_digest_final(hashctx, digest + have, mdsz) != 0) {
801 r = SSH_ERR_LIBCRYPTO_ERROR;
804 ssh_digest_free(hashctx);
808 fprintf(stderr, "key '%c'== ", c);
809 dump_digest("key", digest, need);
817 ssh_digest_free(hashctx);
823 kex_derive_keys(struct ssh *ssh, u_char *hash, u_int hashlen,
824 const struct sshbuf *shared_secret)
826 struct kex *kex = ssh->kex;
828 u_int i, j, mode, ctos;
831 for (i = 0; i < NKEYS; i++) {
832 if ((r = derive_key(ssh, 'A'+i, kex->we_need, hash, hashlen,
833 shared_secret, &keys[i])) != 0) {
834 for (j = 0; j < i; j++)
839 for (mode = 0; mode < MODE_MAX; mode++) {
840 ctos = (!kex->server && mode == MODE_OUT) ||
841 (kex->server && mode == MODE_IN);
842 kex->newkeys[mode]->enc.iv = keys[ctos ? 0 : 1];
843 kex->newkeys[mode]->enc.key = keys[ctos ? 2 : 3];
844 kex->newkeys[mode]->mac.key = keys[ctos ? 4 : 5];
851 kex_derive_keys_bn(struct ssh *ssh, u_char *hash, u_int hashlen,
852 const BIGNUM *secret)
854 struct sshbuf *shared_secret;
857 if ((shared_secret = sshbuf_new()) == NULL)
858 return SSH_ERR_ALLOC_FAIL;
859 if ((r = sshbuf_put_bignum2(shared_secret, secret)) == 0)
860 r = kex_derive_keys(ssh, hash, hashlen, shared_secret);
861 sshbuf_free(shared_secret);
868 derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
869 u_int8_t cookie[8], u_int8_t id[16])
871 u_int8_t hbuf[2048], sbuf[2048], obuf[SSH_DIGEST_MAX_LENGTH];
872 struct ssh_digest_ctx *hashctx = NULL;
876 hlen = BN_num_bytes(host_modulus);
877 slen = BN_num_bytes(server_modulus);
878 if (hlen < (512 / 8) || (u_int)hlen > sizeof(hbuf) ||
879 slen < (512 / 8) || (u_int)slen > sizeof(sbuf))
880 return SSH_ERR_KEY_BITS_MISMATCH;
881 if (BN_bn2bin(host_modulus, hbuf) <= 0 ||
882 BN_bn2bin(server_modulus, sbuf) <= 0) {
883 r = SSH_ERR_LIBCRYPTO_ERROR;
886 if ((hashctx = ssh_digest_start(SSH_DIGEST_MD5)) == NULL) {
887 r = SSH_ERR_ALLOC_FAIL;
890 if (ssh_digest_update(hashctx, hbuf, hlen) != 0 ||
891 ssh_digest_update(hashctx, sbuf, slen) != 0 ||
892 ssh_digest_update(hashctx, cookie, 8) != 0 ||
893 ssh_digest_final(hashctx, obuf, sizeof(obuf)) != 0) {
894 r = SSH_ERR_LIBCRYPTO_ERROR;
897 memcpy(id, obuf, ssh_digest_bytes(SSH_DIGEST_MD5));
900 ssh_digest_free(hashctx);
901 explicit_bzero(hbuf, sizeof(hbuf));
902 explicit_bzero(sbuf, sizeof(sbuf));
903 explicit_bzero(obuf, sizeof(obuf));
908 #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
910 dump_digest(char *msg, u_char *digest, int len)
912 fprintf(stderr, "%s\n", msg);
913 sshbuf_dump_data(digest, len, stderr);