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1 | /* $OpenBSD: kex.c,v 1.82 2009/10/24 11:13:54 andreas 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 | #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 "roaming.h" | |
52 | ||
53 | #if OPENSSL_VERSION_NUMBER >= 0x00907000L | |
54 | # if defined(HAVE_EVP_SHA256) | |
55 | # define evp_ssh_sha256 EVP_sha256 | |
56 | # else | |
57 | extern const EVP_MD *evp_ssh_sha256(void); | |
58 | # endif | |
59 | #endif | |
60 | ||
61 | /* prototype */ | |
62 | static void kex_kexinit_finish(Kex *); | |
63 | static void kex_choose_conf(Kex *); | |
64 | ||
65 | /* put algorithm proposal into buffer */ | |
66 | static void | |
67 | kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) | |
68 | { | |
69 | u_int i; | |
70 | ||
71 | buffer_clear(b); | |
72 | /* | |
73 | * add a dummy cookie, the cookie will be overwritten by | |
74 | * kex_send_kexinit(), each time a kexinit is set | |
75 | */ | |
76 | for (i = 0; i < KEX_COOKIE_LEN; i++) | |
77 | buffer_put_char(b, 0); | |
78 | for (i = 0; i < PROPOSAL_MAX; i++) | |
79 | buffer_put_cstring(b, proposal[i]); | |
80 | buffer_put_char(b, 0); /* first_kex_packet_follows */ | |
81 | buffer_put_int(b, 0); /* uint32 reserved */ | |
82 | } | |
83 | ||
84 | /* parse buffer and return algorithm proposal */ | |
85 | static char ** | |
86 | kex_buf2prop(Buffer *raw, int *first_kex_follows) | |
87 | { | |
88 | Buffer b; | |
89 | u_int i; | |
90 | char **proposal; | |
91 | ||
92 | proposal = xcalloc(PROPOSAL_MAX, sizeof(char *)); | |
93 | ||
94 | buffer_init(&b); | |
95 | buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); | |
96 | /* skip cookie */ | |
97 | for (i = 0; i < KEX_COOKIE_LEN; i++) | |
98 | buffer_get_char(&b); | |
99 | /* extract kex init proposal strings */ | |
100 | for (i = 0; i < PROPOSAL_MAX; i++) { | |
101 | proposal[i] = buffer_get_string(&b,NULL); | |
102 | debug2("kex_parse_kexinit: %s", proposal[i]); | |
103 | } | |
104 | /* first kex follows / reserved */ | |
105 | i = buffer_get_char(&b); | |
106 | if (first_kex_follows != NULL) | |
107 | *first_kex_follows = i; | |
108 | debug2("kex_parse_kexinit: first_kex_follows %d ", i); | |
109 | i = buffer_get_int(&b); | |
110 | debug2("kex_parse_kexinit: reserved %u ", i); | |
111 | buffer_free(&b); | |
112 | return proposal; | |
113 | } | |
114 | ||
115 | static void | |
116 | kex_prop_free(char **proposal) | |
117 | { | |
118 | u_int i; | |
119 | ||
120 | for (i = 0; i < PROPOSAL_MAX; i++) | |
121 | xfree(proposal[i]); | |
122 | xfree(proposal); | |
123 | } | |
124 | ||
125 | /* ARGSUSED */ | |
126 | static void | |
127 | kex_protocol_error(int type, u_int32_t seq, void *ctxt) | |
128 | { | |
129 | error("Hm, kex protocol error: type %d seq %u", type, seq); | |
130 | } | |
131 | ||
132 | static void | |
133 | kex_reset_dispatch(void) | |
134 | { | |
135 | dispatch_range(SSH2_MSG_TRANSPORT_MIN, | |
136 | SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); | |
137 | dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); | |
138 | } | |
139 | ||
140 | void | |
141 | kex_finish(Kex *kex) | |
142 | { | |
143 | kex_reset_dispatch(); | |
144 | ||
145 | packet_start(SSH2_MSG_NEWKEYS); | |
146 | packet_send(); | |
147 | /* packet_write_wait(); */ | |
148 | debug("SSH2_MSG_NEWKEYS sent"); | |
149 | ||
150 | debug("expecting SSH2_MSG_NEWKEYS"); | |
151 | packet_read_expect(SSH2_MSG_NEWKEYS); | |
152 | packet_check_eom(); | |
153 | debug("SSH2_MSG_NEWKEYS received"); | |
154 | ||
155 | kex->done = 1; | |
156 | buffer_clear(&kex->peer); | |
157 | /* buffer_clear(&kex->my); */ | |
158 | kex->flags &= ~KEX_INIT_SENT; | |
159 | xfree(kex->name); | |
160 | kex->name = NULL; | |
161 | } | |
162 | ||
163 | void | |
164 | kex_send_kexinit(Kex *kex) | |
165 | { | |
166 | u_int32_t rnd = 0; | |
167 | u_char *cookie; | |
168 | u_int i; | |
169 | ||
170 | if (kex == NULL) { | |
171 | error("kex_send_kexinit: no kex, cannot rekey"); | |
172 | return; | |
173 | } | |
174 | if (kex->flags & KEX_INIT_SENT) { | |
175 | debug("KEX_INIT_SENT"); | |
176 | return; | |
177 | } | |
178 | kex->done = 0; | |
179 | ||
180 | /* generate a random cookie */ | |
181 | if (buffer_len(&kex->my) < KEX_COOKIE_LEN) | |
182 | fatal("kex_send_kexinit: kex proposal too short"); | |
183 | cookie = buffer_ptr(&kex->my); | |
184 | for (i = 0; i < KEX_COOKIE_LEN; i++) { | |
185 | if (i % 4 == 0) | |
186 | rnd = arc4random(); | |
187 | cookie[i] = rnd; | |
188 | rnd >>= 8; | |
189 | } | |
190 | packet_start(SSH2_MSG_KEXINIT); | |
191 | packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); | |
192 | packet_send(); | |
193 | debug("SSH2_MSG_KEXINIT sent"); | |
194 | kex->flags |= KEX_INIT_SENT; | |
195 | } | |
196 | ||
197 | /* ARGSUSED */ | |
198 | void | |
199 | kex_input_kexinit(int type, u_int32_t seq, void *ctxt) | |
200 | { | |
201 | char *ptr; | |
202 | u_int i, dlen; | |
203 | Kex *kex = (Kex *)ctxt; | |
204 | ||
205 | debug("SSH2_MSG_KEXINIT received"); | |
206 | if (kex == NULL) | |
207 | fatal("kex_input_kexinit: no kex, cannot rekey"); | |
208 | ||
209 | ptr = packet_get_raw(&dlen); | |
210 | buffer_append(&kex->peer, ptr, dlen); | |
211 | ||
212 | /* discard packet */ | |
213 | for (i = 0; i < KEX_COOKIE_LEN; i++) | |
214 | packet_get_char(); | |
215 | for (i = 0; i < PROPOSAL_MAX; i++) | |
216 | xfree(packet_get_string(NULL)); | |
217 | (void) packet_get_char(); | |
218 | (void) packet_get_int(); | |
219 | packet_check_eom(); | |
220 | ||
221 | kex_kexinit_finish(kex); | |
222 | } | |
223 | ||
224 | Kex * | |
225 | kex_setup(char *proposal[PROPOSAL_MAX]) | |
226 | { | |
227 | Kex *kex; | |
228 | ||
229 | kex = xcalloc(1, sizeof(*kex)); | |
230 | buffer_init(&kex->peer); | |
231 | buffer_init(&kex->my); | |
232 | kex_prop2buf(&kex->my, proposal); | |
233 | kex->done = 0; | |
234 | ||
235 | kex_send_kexinit(kex); /* we start */ | |
236 | kex_reset_dispatch(); | |
237 | ||
238 | return kex; | |
239 | } | |
240 | ||
241 | static void | |
242 | kex_kexinit_finish(Kex *kex) | |
243 | { | |
244 | if (!(kex->flags & KEX_INIT_SENT)) | |
245 | kex_send_kexinit(kex); | |
246 | ||
247 | kex_choose_conf(kex); | |
248 | ||
249 | if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX && | |
250 | kex->kex[kex->kex_type] != NULL) { | |
251 | (kex->kex[kex->kex_type])(kex); | |
252 | } else { | |
253 | fatal("Unsupported key exchange %d", kex->kex_type); | |
254 | } | |
255 | } | |
256 | ||
257 | static void | |
258 | choose_enc(Enc *enc, char *client, char *server) | |
259 | { | |
260 | char *name = match_list(client, server, NULL); | |
261 | if (name == NULL) | |
262 | fatal("no matching cipher found: client %s server %s", | |
263 | client, server); | |
264 | if ((enc->cipher = cipher_by_name(name)) == NULL) | |
265 | fatal("matching cipher is not supported: %s", name); | |
266 | enc->name = name; | |
267 | enc->enabled = 0; | |
268 | enc->iv = NULL; | |
269 | enc->key = NULL; | |
270 | enc->key_len = cipher_keylen(enc->cipher); | |
271 | enc->block_size = cipher_blocksize(enc->cipher); | |
272 | } | |
273 | ||
274 | static void | |
275 | choose_mac(Mac *mac, char *client, char *server) | |
276 | { | |
277 | char *name = match_list(client, server, NULL); | |
278 | if (name == NULL) | |
279 | fatal("no matching mac found: client %s server %s", | |
280 | client, server); | |
281 | if (mac_setup(mac, name) < 0) | |
282 | fatal("unsupported mac %s", name); | |
283 | /* truncate the key */ | |
284 | if (datafellows & SSH_BUG_HMAC) | |
285 | mac->key_len = 16; | |
286 | mac->name = name; | |
287 | mac->key = NULL; | |
288 | mac->enabled = 0; | |
289 | } | |
290 | ||
291 | static void | |
292 | choose_comp(Comp *comp, char *client, char *server) | |
293 | { | |
294 | char *name = match_list(client, server, NULL); | |
295 | if (name == NULL) | |
296 | fatal("no matching comp found: client %s server %s", client, server); | |
297 | if (strcmp(name, "zlib@openssh.com") == 0) { | |
298 | comp->type = COMP_DELAYED; | |
299 | } else if (strcmp(name, "zlib") == 0) { | |
300 | comp->type = COMP_ZLIB; | |
301 | } else if (strcmp(name, "none") == 0) { | |
302 | comp->type = COMP_NONE; | |
303 | } else { | |
304 | fatal("unsupported comp %s", name); | |
305 | } | |
306 | comp->name = name; | |
307 | } | |
308 | ||
309 | static void | |
310 | choose_kex(Kex *k, char *client, char *server) | |
311 | { | |
312 | k->name = match_list(client, server, NULL); | |
313 | if (k->name == NULL) | |
314 | fatal("Unable to negotiate a key exchange method"); | |
315 | if (strcmp(k->name, KEX_DH1) == 0) { | |
316 | k->kex_type = KEX_DH_GRP1_SHA1; | |
317 | k->evp_md = EVP_sha1(); | |
318 | } else if (strcmp(k->name, KEX_DH14) == 0) { | |
319 | k->kex_type = KEX_DH_GRP14_SHA1; | |
320 | k->evp_md = EVP_sha1(); | |
321 | } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) { | |
322 | k->kex_type = KEX_DH_GEX_SHA1; | |
323 | k->evp_md = EVP_sha1(); | |
324 | #if OPENSSL_VERSION_NUMBER >= 0x00907000L | |
325 | } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) { | |
326 | k->kex_type = KEX_DH_GEX_SHA256; | |
327 | k->evp_md = evp_ssh_sha256(); | |
328 | #endif | |
329 | } else | |
330 | fatal("bad kex alg %s", k->name); | |
331 | } | |
332 | ||
333 | static void | |
334 | choose_hostkeyalg(Kex *k, char *client, char *server) | |
335 | { | |
336 | char *hostkeyalg = match_list(client, server, NULL); | |
337 | if (hostkeyalg == NULL) | |
338 | fatal("no hostkey alg"); | |
339 | k->hostkey_type = key_type_from_name(hostkeyalg); | |
340 | if (k->hostkey_type == KEY_UNSPEC) | |
341 | fatal("bad hostkey alg '%s'", hostkeyalg); | |
342 | xfree(hostkeyalg); | |
343 | } | |
344 | ||
345 | static int | |
346 | proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) | |
347 | { | |
348 | static int check[] = { | |
349 | PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 | |
350 | }; | |
351 | int *idx; | |
352 | char *p; | |
353 | ||
354 | for (idx = &check[0]; *idx != -1; idx++) { | |
355 | if ((p = strchr(my[*idx], ',')) != NULL) | |
356 | *p = '\0'; | |
357 | if ((p = strchr(peer[*idx], ',')) != NULL) | |
358 | *p = '\0'; | |
359 | if (strcmp(my[*idx], peer[*idx]) != 0) { | |
360 | debug2("proposal mismatch: my %s peer %s", | |
361 | my[*idx], peer[*idx]); | |
362 | return (0); | |
363 | } | |
364 | } | |
365 | debug2("proposals match"); | |
366 | return (1); | |
367 | } | |
368 | ||
369 | static void | |
370 | kex_choose_conf(Kex *kex) | |
371 | { | |
372 | Newkeys *newkeys; | |
373 | char **my, **peer; | |
374 | char **cprop, **sprop; | |
375 | int nenc, nmac, ncomp; | |
376 | u_int mode, ctos, need; | |
377 | int first_kex_follows, type; | |
378 | ||
379 | my = kex_buf2prop(&kex->my, NULL); | |
380 | peer = kex_buf2prop(&kex->peer, &first_kex_follows); | |
381 | ||
382 | if (kex->server) { | |
383 | cprop=peer; | |
384 | sprop=my; | |
385 | } else { | |
386 | cprop=my; | |
387 | sprop=peer; | |
388 | } | |
389 | ||
390 | /* Check whether server offers roaming */ | |
391 | if (!kex->server) { | |
392 | char *roaming; | |
393 | roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL); | |
394 | if (roaming) { | |
395 | kex->roaming = 1; | |
396 | xfree(roaming); | |
397 | } | |
398 | } | |
399 | ||
400 | /* Algorithm Negotiation */ | |
401 | for (mode = 0; mode < MODE_MAX; mode++) { | |
402 | newkeys = xcalloc(1, sizeof(*newkeys)); | |
403 | kex->newkeys[mode] = newkeys; | |
404 | ctos = (!kex->server && mode == MODE_OUT) || | |
405 | (kex->server && mode == MODE_IN); | |
406 | nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; | |
407 | nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; | |
408 | ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; | |
409 | choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]); | |
410 | choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]); | |
411 | choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); | |
412 | debug("kex: %s %s %s %s", | |
413 | ctos ? "client->server" : "server->client", | |
414 | newkeys->enc.name, | |
415 | newkeys->mac.name, | |
416 | newkeys->comp.name); | |
417 | } | |
418 | choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); | |
419 | choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], | |
420 | sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); | |
421 | need = 0; | |
422 | for (mode = 0; mode < MODE_MAX; mode++) { | |
423 | newkeys = kex->newkeys[mode]; | |
424 | if (need < newkeys->enc.key_len) | |
425 | need = newkeys->enc.key_len; | |
426 | if (need < newkeys->enc.block_size) | |
427 | need = newkeys->enc.block_size; | |
428 | if (need < newkeys->mac.key_len) | |
429 | need = newkeys->mac.key_len; | |
430 | } | |
431 | /* XXX need runden? */ | |
432 | kex->we_need = need; | |
433 | ||
434 | /* ignore the next message if the proposals do not match */ | |
435 | if (first_kex_follows && !proposals_match(my, peer) && | |
436 | !(datafellows & SSH_BUG_FIRSTKEX)) { | |
437 | type = packet_read(); | |
438 | debug2("skipping next packet (type %u)", type); | |
439 | } | |
440 | ||
441 | kex_prop_free(my); | |
442 | kex_prop_free(peer); | |
443 | } | |
444 | ||
445 | static u_char * | |
446 | derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen, | |
447 | BIGNUM *shared_secret) | |
448 | { | |
449 | Buffer b; | |
450 | EVP_MD_CTX md; | |
451 | char c = id; | |
452 | u_int have; | |
453 | int mdsz; | |
454 | u_char *digest; | |
455 | ||
456 | if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0) | |
457 | fatal("bad kex md size %d", mdsz); | |
458 | digest = xmalloc(roundup(need, mdsz)); | |
459 | ||
460 | buffer_init(&b); | |
461 | buffer_put_bignum2(&b, shared_secret); | |
462 | ||
463 | /* K1 = HASH(K || H || "A" || session_id) */ | |
464 | EVP_DigestInit(&md, kex->evp_md); | |
465 | if (!(datafellows & SSH_BUG_DERIVEKEY)) | |
466 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); | |
467 | EVP_DigestUpdate(&md, hash, hashlen); | |
468 | EVP_DigestUpdate(&md, &c, 1); | |
469 | EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); | |
470 | EVP_DigestFinal(&md, digest, NULL); | |
471 | ||
472 | /* | |
473 | * expand key: | |
474 | * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) | |
475 | * Key = K1 || K2 || ... || Kn | |
476 | */ | |
477 | for (have = mdsz; need > have; have += mdsz) { | |
478 | EVP_DigestInit(&md, kex->evp_md); | |
479 | if (!(datafellows & SSH_BUG_DERIVEKEY)) | |
480 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); | |
481 | EVP_DigestUpdate(&md, hash, hashlen); | |
482 | EVP_DigestUpdate(&md, digest, have); | |
483 | EVP_DigestFinal(&md, digest + have, NULL); | |
484 | } | |
485 | buffer_free(&b); | |
486 | #ifdef DEBUG_KEX | |
487 | fprintf(stderr, "key '%c'== ", c); | |
488 | dump_digest("key", digest, need); | |
489 | #endif | |
490 | return digest; | |
491 | } | |
492 | ||
493 | Newkeys *current_keys[MODE_MAX]; | |
494 | ||
495 | #define NKEYS 6 | |
496 | void | |
497 | kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret) | |
498 | { | |
499 | u_char *keys[NKEYS]; | |
500 | u_int i, mode, ctos; | |
501 | ||
502 | for (i = 0; i < NKEYS; i++) { | |
503 | keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen, | |
504 | shared_secret); | |
505 | } | |
506 | ||
507 | debug2("kex_derive_keys"); | |
508 | for (mode = 0; mode < MODE_MAX; mode++) { | |
509 | current_keys[mode] = kex->newkeys[mode]; | |
510 | kex->newkeys[mode] = NULL; | |
511 | ctos = (!kex->server && mode == MODE_OUT) || | |
512 | (kex->server && mode == MODE_IN); | |
513 | current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; | |
514 | current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; | |
515 | current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; | |
516 | } | |
517 | } | |
518 | ||
519 | Newkeys * | |
520 | kex_get_newkeys(int mode) | |
521 | { | |
522 | Newkeys *ret; | |
523 | ||
524 | ret = current_keys[mode]; | |
525 | current_keys[mode] = NULL; | |
526 | return ret; | |
527 | } | |
528 | ||
529 | void | |
530 | derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus, | |
531 | u_int8_t cookie[8], u_int8_t id[16]) | |
532 | { | |
533 | const EVP_MD *evp_md = EVP_md5(); | |
534 | EVP_MD_CTX md; | |
535 | u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE]; | |
536 | int len; | |
537 | ||
538 | EVP_DigestInit(&md, evp_md); | |
539 | ||
540 | len = BN_num_bytes(host_modulus); | |
541 | if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) | |
542 | fatal("%s: bad host modulus (len %d)", __func__, len); | |
543 | BN_bn2bin(host_modulus, nbuf); | |
544 | EVP_DigestUpdate(&md, nbuf, len); | |
545 | ||
546 | len = BN_num_bytes(server_modulus); | |
547 | if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) | |
548 | fatal("%s: bad server modulus (len %d)", __func__, len); | |
549 | BN_bn2bin(server_modulus, nbuf); | |
550 | EVP_DigestUpdate(&md, nbuf, len); | |
551 | ||
552 | EVP_DigestUpdate(&md, cookie, 8); | |
553 | ||
554 | EVP_DigestFinal(&md, obuf, NULL); | |
555 | memcpy(id, obuf, 16); | |
556 | ||
557 | memset(nbuf, 0, sizeof(nbuf)); | |
558 | memset(obuf, 0, sizeof(obuf)); | |
559 | memset(&md, 0, sizeof(md)); | |
560 | } | |
561 | ||
562 | #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) | |
563 | void | |
564 | dump_digest(char *msg, u_char *digest, int len) | |
565 | { | |
566 | u_int i; | |
567 | ||
568 | fprintf(stderr, "%s\n", msg); | |
569 | for (i = 0; i < len; i++) { | |
570 | fprintf(stderr, "%02x", digest[i]); | |
571 | if (i%32 == 31) | |
572 | fprintf(stderr, "\n"); | |
573 | else if (i%8 == 7) | |
574 | fprintf(stderr, " "); | |
575 | } | |
576 | fprintf(stderr, "\n"); | |
577 | } | |
578 | #endif |