Annotation of src/usr.bin/ssh/kex.c, Revision 1.80
1.80 ! djm 1: /* $OpenBSD: kex.c,v 1.79 2007/06/05 06:52:37 djm Exp $ */
1.1 markus 2: /*
1.36 markus 3: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.1 markus 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:
1.73 stevesk 26: #include <sys/param.h>
1.18 markus 27:
1.76 deraadt 28: #include <signal.h>
1.75 stevesk 29: #include <stdio.h>
1.74 stevesk 30: #include <stdlib.h>
1.72 stevesk 31: #include <string.h>
1.1 markus 32:
1.76 deraadt 33: #include <openssl/crypto.h>
34:
35: #include "xmalloc.h"
1.1 markus 36: #include "ssh2.h"
37: #include "buffer.h"
1.7 markus 38: #include "packet.h"
1.1 markus 39: #include "compat.h"
1.18 markus 40: #include "cipher.h"
1.76 deraadt 41: #include "key.h"
1.1 markus 42: #include "kex.h"
1.18 markus 43: #include "log.h"
1.21 markus 44: #include "mac.h"
1.23 markus 45: #include "match.h"
1.26 markus 46: #include "dispatch.h"
1.48 provos 47: #include "monitor.h"
1.1 markus 48:
1.7 markus 49: #define KEX_COOKIE_LEN 16
1.48 provos 50:
1.35 itojun 51: /* prototype */
52: static void kex_kexinit_finish(Kex *);
53: static void kex_choose_conf(Kex *);
1.26 markus 54:
55: /* put algorithm proposal into buffer */
1.35 itojun 56: static void
1.26 markus 57: kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
1.1 markus 58: {
1.61 djm 59: u_int i;
1.26 markus 60:
61: buffer_clear(b);
1.49 markus 62: /*
63: * add a dummy cookie, the cookie will be overwritten by
64: * kex_send_kexinit(), each time a kexinit is set
65: */
66: for (i = 0; i < KEX_COOKIE_LEN; i++)
67: buffer_put_char(b, 0);
1.1 markus 68: for (i = 0; i < PROPOSAL_MAX; i++)
1.26 markus 69: buffer_put_cstring(b, proposal[i]);
70: buffer_put_char(b, 0); /* first_kex_packet_follows */
71: buffer_put_int(b, 0); /* uint32 reserved */
1.1 markus 72: }
73:
1.26 markus 74: /* parse buffer and return algorithm proposal */
1.35 itojun 75: static char **
1.53 markus 76: kex_buf2prop(Buffer *raw, int *first_kex_follows)
1.7 markus 77: {
1.26 markus 78: Buffer b;
1.78 djm 79: u_int i;
1.26 markus 80: char **proposal;
1.7 markus 81:
1.70 djm 82: proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
1.7 markus 83:
1.26 markus 84: buffer_init(&b);
85: buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
1.7 markus 86: /* skip cookie */
87: for (i = 0; i < KEX_COOKIE_LEN; i++)
1.26 markus 88: buffer_get_char(&b);
1.7 markus 89: /* extract kex init proposal strings */
90: for (i = 0; i < PROPOSAL_MAX; i++) {
1.26 markus 91: proposal[i] = buffer_get_string(&b,NULL);
92: debug2("kex_parse_kexinit: %s", proposal[i]);
1.7 markus 93: }
1.26 markus 94: /* first kex follows / reserved */
95: i = buffer_get_char(&b);
1.53 markus 96: if (first_kex_follows != NULL)
97: *first_kex_follows = i;
1.26 markus 98: debug2("kex_parse_kexinit: first_kex_follows %d ", i);
99: i = buffer_get_int(&b);
1.78 djm 100: debug2("kex_parse_kexinit: reserved %u ", i);
1.26 markus 101: buffer_free(&b);
102: return proposal;
1.1 markus 103: }
104:
1.35 itojun 105: static void
1.26 markus 106: kex_prop_free(char **proposal)
1.1 markus 107: {
1.61 djm 108: u_int i;
1.26 markus 109:
110: for (i = 0; i < PROPOSAL_MAX; i++)
111: xfree(proposal[i]);
112: xfree(proposal);
1.1 markus 113: }
114:
1.78 djm 115: /* ARGSUSED */
1.35 itojun 116: static void
1.41 markus 117: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 118: {
1.41 markus 119: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 120: }
1.1 markus 121:
1.35 itojun 122: static void
1.44 markus 123: kex_reset_dispatch(void)
1.29 markus 124: {
1.42 markus 125: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
126: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 127: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 128: }
129:
130: void
1.28 markus 131: kex_finish(Kex *kex)
1.26 markus 132: {
1.44 markus 133: kex_reset_dispatch();
1.28 markus 134:
1.26 markus 135: packet_start(SSH2_MSG_NEWKEYS);
136: packet_send();
137: /* packet_write_wait(); */
138: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 139:
1.52 markus 140: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 141: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 142: packet_check_eom();
1.26 markus 143: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 144:
1.30 markus 145: kex->done = 1;
1.26 markus 146: buffer_clear(&kex->peer);
1.27 markus 147: /* buffer_clear(&kex->my); */
1.26 markus 148: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 149: xfree(kex->name);
150: kex->name = NULL;
1.26 markus 151: }
1.1 markus 152:
1.26 markus 153: void
154: kex_send_kexinit(Kex *kex)
155: {
1.60 avsm 156: u_int32_t rnd = 0;
1.49 markus 157: u_char *cookie;
1.61 djm 158: u_int i;
1.49 markus 159:
1.29 markus 160: if (kex == NULL) {
161: error("kex_send_kexinit: no kex, cannot rekey");
162: return;
163: }
1.28 markus 164: if (kex->flags & KEX_INIT_SENT) {
165: debug("KEX_INIT_SENT");
166: return;
167: }
1.30 markus 168: kex->done = 0;
1.49 markus 169:
170: /* generate a random cookie */
171: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
172: fatal("kex_send_kexinit: kex proposal too short");
173: cookie = buffer_ptr(&kex->my);
174: for (i = 0; i < KEX_COOKIE_LEN; i++) {
175: if (i % 4 == 0)
1.60 avsm 176: rnd = arc4random();
177: cookie[i] = rnd;
178: rnd >>= 8;
1.49 markus 179: }
1.26 markus 180: packet_start(SSH2_MSG_KEXINIT);
181: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
182: packet_send();
183: debug("SSH2_MSG_KEXINIT sent");
184: kex->flags |= KEX_INIT_SENT;
1.1 markus 185: }
186:
1.78 djm 187: /* ARGSUSED */
1.26 markus 188: void
1.41 markus 189: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 190: {
1.26 markus 191: char *ptr;
1.61 djm 192: u_int i, dlen;
1.26 markus 193: Kex *kex = (Kex *)ctxt;
1.11 provos 194:
1.26 markus 195: debug("SSH2_MSG_KEXINIT received");
1.29 markus 196: if (kex == NULL)
197: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 198:
1.26 markus 199: ptr = packet_get_raw(&dlen);
200: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 201:
202: /* discard packet */
203: for (i = 0; i < KEX_COOKIE_LEN; i++)
204: packet_get_char();
205: for (i = 0; i < PROPOSAL_MAX; i++)
206: xfree(packet_get_string(NULL));
1.51 markus 207: (void) packet_get_char();
208: (void) packet_get_int();
1.39 markus 209: packet_check_eom();
1.19 stevesk 210:
1.26 markus 211: kex_kexinit_finish(kex);
212: }
1.11 provos 213:
1.26 markus 214: Kex *
1.28 markus 215: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 216: {
217: Kex *kex;
1.11 provos 218:
1.70 djm 219: kex = xcalloc(1, sizeof(*kex));
1.26 markus 220: buffer_init(&kex->peer);
221: buffer_init(&kex->my);
222: kex_prop2buf(&kex->my, proposal);
1.30 markus 223: kex->done = 0;
1.26 markus 224:
225: kex_send_kexinit(kex); /* we start */
1.44 markus 226: kex_reset_dispatch();
1.26 markus 227:
228: return kex;
1.11 provos 229: }
230:
1.35 itojun 231: static void
1.26 markus 232: kex_kexinit_finish(Kex *kex)
1.1 markus 233: {
1.26 markus 234: if (!(kex->flags & KEX_INIT_SENT))
235: kex_send_kexinit(kex);
1.1 markus 236:
1.26 markus 237: kex_choose_conf(kex);
1.1 markus 238:
1.54 markus 239: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
240: kex->kex[kex->kex_type] != NULL) {
241: (kex->kex[kex->kex_type])(kex);
242: } else {
1.26 markus 243: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 244: }
245: }
246:
1.35 itojun 247: static void
1.1 markus 248: choose_enc(Enc *enc, char *client, char *server)
249: {
1.23 markus 250: char *name = match_list(client, server, NULL);
1.1 markus 251: if (name == NULL)
1.78 djm 252: fatal("no matching cipher found: client %s server %s",
253: client, server);
1.45 markus 254: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 255: fatal("matching cipher is not supported: %s", name);
1.1 markus 256: enc->name = name;
257: enc->enabled = 0;
258: enc->iv = NULL;
259: enc->key = NULL;
1.45 markus 260: enc->key_len = cipher_keylen(enc->cipher);
261: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 262: }
1.69 deraadt 263:
1.35 itojun 264: static void
1.1 markus 265: choose_mac(Mac *mac, char *client, char *server)
266: {
1.23 markus 267: char *name = match_list(client, server, NULL);
1.1 markus 268: if (name == NULL)
1.78 djm 269: fatal("no matching mac found: client %s server %s",
270: client, server);
1.79 djm 271: if (mac_setup(mac, name) < 0)
1.1 markus 272: fatal("unsupported mac %s", name);
1.21 markus 273: /* truncate the key */
274: if (datafellows & SSH_BUG_HMAC)
275: mac->key_len = 16;
1.1 markus 276: mac->name = name;
277: mac->key = NULL;
278: mac->enabled = 0;
279: }
1.69 deraadt 280:
1.35 itojun 281: static void
1.1 markus 282: choose_comp(Comp *comp, char *client, char *server)
283: {
1.23 markus 284: char *name = match_list(client, server, NULL);
1.1 markus 285: if (name == NULL)
286: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 287: if (strcmp(name, "zlib@openssh.com") == 0) {
288: comp->type = COMP_DELAYED;
289: } else if (strcmp(name, "zlib") == 0) {
290: comp->type = COMP_ZLIB;
1.1 markus 291: } else if (strcmp(name, "none") == 0) {
1.64 markus 292: comp->type = COMP_NONE;
1.1 markus 293: } else {
294: fatal("unsupported comp %s", name);
295: }
296: comp->name = name;
297: }
1.69 deraadt 298:
1.35 itojun 299: static void
1.1 markus 300: choose_kex(Kex *k, char *client, char *server)
301: {
1.23 markus 302: k->name = match_list(client, server, NULL);
1.1 markus 303: if (k->name == NULL)
1.78 djm 304: fatal("Unable to negotiate a key exchange method");
1.11 provos 305: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 306: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 307: k->evp_md = EVP_sha1();
1.59 djm 308: } else if (strcmp(k->name, KEX_DH14) == 0) {
309: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 310: k->evp_md = EVP_sha1();
311: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 312: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 313: k->evp_md = EVP_sha1();
1.66 djm 314: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
315: k->kex_type = KEX_DH_GEX_SHA256;
1.80 ! djm 316: k->evp_md = EVP_sha256();
1.11 provos 317: } else
1.1 markus 318: fatal("bad kex alg %s", k->name);
319: }
1.65 djm 320:
1.35 itojun 321: static void
1.1 markus 322: choose_hostkeyalg(Kex *k, char *client, char *server)
323: {
1.23 markus 324: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 325: if (hostkeyalg == NULL)
1.1 markus 326: fatal("no hostkey alg");
1.13 markus 327: k->hostkey_type = key_type_from_name(hostkeyalg);
328: if (k->hostkey_type == KEY_UNSPEC)
329: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 330: xfree(hostkeyalg);
1.1 markus 331: }
332:
1.56 djm 333: static int
1.53 markus 334: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
335: {
336: static int check[] = {
337: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
338: };
339: int *idx;
340: char *p;
341:
342: for (idx = &check[0]; *idx != -1; idx++) {
343: if ((p = strchr(my[*idx], ',')) != NULL)
344: *p = '\0';
345: if ((p = strchr(peer[*idx], ',')) != NULL)
346: *p = '\0';
347: if (strcmp(my[*idx], peer[*idx]) != 0) {
348: debug2("proposal mismatch: my %s peer %s",
349: my[*idx], peer[*idx]);
350: return (0);
351: }
352: }
353: debug2("proposals match");
354: return (1);
355: }
356:
1.35 itojun 357: static void
1.27 markus 358: kex_choose_conf(Kex *kex)
1.1 markus 359: {
1.27 markus 360: Newkeys *newkeys;
1.26 markus 361: char **my, **peer;
362: char **cprop, **sprop;
1.27 markus 363: int nenc, nmac, ncomp;
1.61 djm 364: u_int mode, ctos, need;
1.53 markus 365: int first_kex_follows, type;
1.1 markus 366:
1.53 markus 367: my = kex_buf2prop(&kex->my, NULL);
368: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 369:
1.27 markus 370: if (kex->server) {
1.26 markus 371: cprop=peer;
372: sprop=my;
373: } else {
374: cprop=my;
375: sprop=peer;
376: }
1.1 markus 377:
1.30 markus 378: /* Algorithm Negotiation */
1.1 markus 379: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 djm 380: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 381: kex->newkeys[mode] = newkeys;
1.78 djm 382: ctos = (!kex->server && mode == MODE_OUT) ||
383: (kex->server && mode == MODE_IN);
1.1 markus 384: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
385: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
386: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 387: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
388: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
389: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 390: debug("kex: %s %s %s %s",
1.1 markus 391: ctos ? "client->server" : "server->client",
1.27 markus 392: newkeys->enc.name,
393: newkeys->mac.name,
394: newkeys->comp.name);
1.1 markus 395: }
1.27 markus 396: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
397: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 398: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
399: need = 0;
400: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 401: newkeys = kex->newkeys[mode];
1.45 markus 402: if (need < newkeys->enc.key_len)
403: need = newkeys->enc.key_len;
404: if (need < newkeys->enc.block_size)
405: need = newkeys->enc.block_size;
1.27 markus 406: if (need < newkeys->mac.key_len)
407: need = newkeys->mac.key_len;
1.1 markus 408: }
1.7 markus 409: /* XXX need runden? */
1.27 markus 410: kex->we_need = need;
1.53 markus 411:
412: /* ignore the next message if the proposals do not match */
1.56 djm 413: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 414: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 415: type = packet_read();
416: debug2("skipping next packet (type %u)", type);
417: }
1.26 markus 418:
419: kex_prop_free(my);
420: kex_prop_free(peer);
421: }
422:
1.35 itojun 423: static u_char *
1.65 djm 424: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
425: BIGNUM *shared_secret)
1.26 markus 426: {
427: Buffer b;
428: EVP_MD_CTX md;
429: char c = id;
1.61 djm 430: u_int have;
1.65 djm 431: int mdsz;
1.61 djm 432: u_char *digest;
1.62 djm 433:
1.65 djm 434: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
435: fatal("bad kex md size %d", mdsz);
1.68 deraadt 436: digest = xmalloc(roundup(need, mdsz));
1.26 markus 437:
438: buffer_init(&b);
439: buffer_put_bignum2(&b, shared_secret);
440:
1.30 markus 441: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 442: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 443: if (!(datafellows & SSH_BUG_DERIVEKEY))
444: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 445: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 446: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 447: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 448: EVP_DigestFinal(&md, digest, NULL);
449:
1.30 markus 450: /*
451: * expand key:
452: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
453: * Key = K1 || K2 || ... || Kn
454: */
1.26 markus 455: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 456: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 457: if (!(datafellows & SSH_BUG_DERIVEKEY))
458: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 459: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 460: EVP_DigestUpdate(&md, digest, have);
461: EVP_DigestFinal(&md, digest + have, NULL);
462: }
463: buffer_free(&b);
464: #ifdef DEBUG_KEX
465: fprintf(stderr, "key '%c'== ", c);
466: dump_digest("key", digest, need);
467: #endif
468: return digest;
1.1 markus 469: }
470:
1.30 markus 471: Newkeys *current_keys[MODE_MAX];
1.27 markus 472:
1.23 markus 473: #define NKEYS 6
1.26 markus 474: void
1.65 djm 475: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 476: {
1.15 markus 477: u_char *keys[NKEYS];
1.61 djm 478: u_int i, mode, ctos;
1.1 markus 479:
1.65 djm 480: for (i = 0; i < NKEYS; i++) {
481: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
482: shared_secret);
483: }
1.1 markus 484:
1.52 markus 485: debug2("kex_derive_keys");
1.1 markus 486: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 487: current_keys[mode] = kex->newkeys[mode];
488: kex->newkeys[mode] = NULL;
1.69 deraadt 489: ctos = (!kex->server && mode == MODE_OUT) ||
490: (kex->server && mode == MODE_IN);
1.30 markus 491: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
492: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
493: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 494: }
1.27 markus 495: }
496:
497: Newkeys *
498: kex_get_newkeys(int mode)
499: {
1.30 markus 500: Newkeys *ret;
501:
502: ret = current_keys[mode];
503: current_keys[mode] = NULL;
504: return ret;
1.57 djm 505: }
506:
507: void
508: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
509: u_int8_t cookie[8], u_int8_t id[16])
510: {
511: const EVP_MD *evp_md = EVP_md5();
512: EVP_MD_CTX md;
513: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
514: int len;
515:
516: EVP_DigestInit(&md, evp_md);
517:
518: len = BN_num_bytes(host_modulus);
1.61 djm 519: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 520: fatal("%s: bad host modulus (len %d)", __func__, len);
521: BN_bn2bin(host_modulus, nbuf);
522: EVP_DigestUpdate(&md, nbuf, len);
523:
524: len = BN_num_bytes(server_modulus);
1.61 djm 525: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 526: fatal("%s: bad server modulus (len %d)", __func__, len);
527: BN_bn2bin(server_modulus, nbuf);
528: EVP_DigestUpdate(&md, nbuf, len);
529:
530: EVP_DigestUpdate(&md, cookie, 8);
531:
1.58 djm 532: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 533: memcpy(id, obuf, 16);
534:
535: memset(nbuf, 0, sizeof(nbuf));
536: memset(obuf, 0, sizeof(obuf));
537: memset(&md, 0, sizeof(md));
1.1 markus 538: }
1.26 markus 539:
540: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
541: void
542: dump_digest(char *msg, u_char *digest, int len)
543: {
1.61 djm 544: u_int i;
1.26 markus 545:
546: fprintf(stderr, "%s\n", msg);
1.77 stevesk 547: for (i = 0; i < len; i++) {
1.26 markus 548: fprintf(stderr, "%02x", digest[i]);
549: if (i%32 == 31)
550: fprintf(stderr, "\n");
551: else if (i%8 == 7)
552: fprintf(stderr, " ");
553: }
554: fprintf(stderr, "\n");
555: }
556: #endif
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