Annotation of src/usr.bin/ssh/kex.c, Revision 1.81
1.81 ! andreas 1: /* $OpenBSD: kex.c,v 1.80 2008/09/06 12:24:13 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"
48:
1.35 itojun 49: /* prototype */
50: static void kex_kexinit_finish(Kex *);
51: static void kex_choose_conf(Kex *);
1.26 markus 52:
53: /* put algorithm proposal into buffer */
1.35 itojun 54: static void
1.26 markus 55: kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
1.1 markus 56: {
1.61 djm 57: u_int i;
1.26 markus 58:
59: buffer_clear(b);
1.49 markus 60: /*
61: * add a dummy cookie, the cookie will be overwritten by
62: * kex_send_kexinit(), each time a kexinit is set
63: */
64: for (i = 0; i < KEX_COOKIE_LEN; i++)
65: buffer_put_char(b, 0);
1.1 markus 66: for (i = 0; i < PROPOSAL_MAX; i++)
1.26 markus 67: buffer_put_cstring(b, proposal[i]);
68: buffer_put_char(b, 0); /* first_kex_packet_follows */
69: buffer_put_int(b, 0); /* uint32 reserved */
1.1 markus 70: }
71:
1.26 markus 72: /* parse buffer and return algorithm proposal */
1.35 itojun 73: static char **
1.53 markus 74: kex_buf2prop(Buffer *raw, int *first_kex_follows)
1.7 markus 75: {
1.26 markus 76: Buffer b;
1.78 djm 77: u_int i;
1.26 markus 78: char **proposal;
1.7 markus 79:
1.70 djm 80: proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
1.7 markus 81:
1.26 markus 82: buffer_init(&b);
83: buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
1.7 markus 84: /* skip cookie */
85: for (i = 0; i < KEX_COOKIE_LEN; i++)
1.26 markus 86: buffer_get_char(&b);
1.7 markus 87: /* extract kex init proposal strings */
88: for (i = 0; i < PROPOSAL_MAX; i++) {
1.26 markus 89: proposal[i] = buffer_get_string(&b,NULL);
90: debug2("kex_parse_kexinit: %s", proposal[i]);
1.7 markus 91: }
1.26 markus 92: /* first kex follows / reserved */
93: i = buffer_get_char(&b);
1.53 markus 94: if (first_kex_follows != NULL)
95: *first_kex_follows = i;
1.26 markus 96: debug2("kex_parse_kexinit: first_kex_follows %d ", i);
97: i = buffer_get_int(&b);
1.78 djm 98: debug2("kex_parse_kexinit: reserved %u ", i);
1.26 markus 99: buffer_free(&b);
100: return proposal;
1.1 markus 101: }
102:
1.35 itojun 103: static void
1.26 markus 104: kex_prop_free(char **proposal)
1.1 markus 105: {
1.61 djm 106: u_int i;
1.26 markus 107:
108: for (i = 0; i < PROPOSAL_MAX; i++)
109: xfree(proposal[i]);
110: xfree(proposal);
1.1 markus 111: }
112:
1.78 djm 113: /* ARGSUSED */
1.35 itojun 114: static void
1.41 markus 115: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 116: {
1.41 markus 117: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 118: }
1.1 markus 119:
1.35 itojun 120: static void
1.44 markus 121: kex_reset_dispatch(void)
1.29 markus 122: {
1.42 markus 123: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
124: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 125: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 126: }
127:
128: void
1.28 markus 129: kex_finish(Kex *kex)
1.26 markus 130: {
1.44 markus 131: kex_reset_dispatch();
1.28 markus 132:
1.26 markus 133: packet_start(SSH2_MSG_NEWKEYS);
134: packet_send();
135: /* packet_write_wait(); */
136: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 137:
1.52 markus 138: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 139: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 140: packet_check_eom();
1.26 markus 141: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 142:
1.30 markus 143: kex->done = 1;
1.26 markus 144: buffer_clear(&kex->peer);
1.27 markus 145: /* buffer_clear(&kex->my); */
1.26 markus 146: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 147: xfree(kex->name);
148: kex->name = NULL;
1.26 markus 149: }
1.1 markus 150:
1.26 markus 151: void
152: kex_send_kexinit(Kex *kex)
153: {
1.60 avsm 154: u_int32_t rnd = 0;
1.49 markus 155: u_char *cookie;
1.61 djm 156: u_int i;
1.49 markus 157:
1.29 markus 158: if (kex == NULL) {
159: error("kex_send_kexinit: no kex, cannot rekey");
160: return;
161: }
1.28 markus 162: if (kex->flags & KEX_INIT_SENT) {
163: debug("KEX_INIT_SENT");
164: return;
165: }
1.30 markus 166: kex->done = 0;
1.49 markus 167:
168: /* generate a random cookie */
169: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
170: fatal("kex_send_kexinit: kex proposal too short");
171: cookie = buffer_ptr(&kex->my);
172: for (i = 0; i < KEX_COOKIE_LEN; i++) {
173: if (i % 4 == 0)
1.60 avsm 174: rnd = arc4random();
175: cookie[i] = rnd;
176: rnd >>= 8;
1.49 markus 177: }
1.26 markus 178: packet_start(SSH2_MSG_KEXINIT);
179: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
180: packet_send();
181: debug("SSH2_MSG_KEXINIT sent");
182: kex->flags |= KEX_INIT_SENT;
1.1 markus 183: }
184:
1.78 djm 185: /* ARGSUSED */
1.26 markus 186: void
1.41 markus 187: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 188: {
1.26 markus 189: char *ptr;
1.61 djm 190: u_int i, dlen;
1.26 markus 191: Kex *kex = (Kex *)ctxt;
1.11 provos 192:
1.26 markus 193: debug("SSH2_MSG_KEXINIT received");
1.29 markus 194: if (kex == NULL)
195: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 196:
1.26 markus 197: ptr = packet_get_raw(&dlen);
198: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 199:
200: /* discard packet */
201: for (i = 0; i < KEX_COOKIE_LEN; i++)
202: packet_get_char();
203: for (i = 0; i < PROPOSAL_MAX; i++)
204: xfree(packet_get_string(NULL));
1.51 markus 205: (void) packet_get_char();
206: (void) packet_get_int();
1.39 markus 207: packet_check_eom();
1.19 stevesk 208:
1.26 markus 209: kex_kexinit_finish(kex);
210: }
1.11 provos 211:
1.26 markus 212: Kex *
1.28 markus 213: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 214: {
215: Kex *kex;
1.11 provos 216:
1.70 djm 217: kex = xcalloc(1, sizeof(*kex));
1.26 markus 218: buffer_init(&kex->peer);
219: buffer_init(&kex->my);
220: kex_prop2buf(&kex->my, proposal);
1.30 markus 221: kex->done = 0;
1.26 markus 222:
223: kex_send_kexinit(kex); /* we start */
1.44 markus 224: kex_reset_dispatch();
1.26 markus 225:
226: return kex;
1.11 provos 227: }
228:
1.35 itojun 229: static void
1.26 markus 230: kex_kexinit_finish(Kex *kex)
1.1 markus 231: {
1.26 markus 232: if (!(kex->flags & KEX_INIT_SENT))
233: kex_send_kexinit(kex);
1.1 markus 234:
1.26 markus 235: kex_choose_conf(kex);
1.1 markus 236:
1.54 markus 237: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
238: kex->kex[kex->kex_type] != NULL) {
239: (kex->kex[kex->kex_type])(kex);
240: } else {
1.26 markus 241: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 242: }
243: }
244:
1.35 itojun 245: static void
1.1 markus 246: choose_enc(Enc *enc, char *client, char *server)
247: {
1.23 markus 248: char *name = match_list(client, server, NULL);
1.1 markus 249: if (name == NULL)
1.78 djm 250: fatal("no matching cipher found: client %s server %s",
251: client, server);
1.45 markus 252: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 253: fatal("matching cipher is not supported: %s", name);
1.1 markus 254: enc->name = name;
255: enc->enabled = 0;
256: enc->iv = NULL;
257: enc->key = NULL;
1.45 markus 258: enc->key_len = cipher_keylen(enc->cipher);
259: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 260: }
1.69 deraadt 261:
1.35 itojun 262: static void
1.1 markus 263: choose_mac(Mac *mac, char *client, char *server)
264: {
1.23 markus 265: char *name = match_list(client, server, NULL);
1.1 markus 266: if (name == NULL)
1.78 djm 267: fatal("no matching mac found: client %s server %s",
268: client, server);
1.79 djm 269: if (mac_setup(mac, name) < 0)
1.1 markus 270: fatal("unsupported mac %s", name);
1.21 markus 271: /* truncate the key */
272: if (datafellows & SSH_BUG_HMAC)
273: mac->key_len = 16;
1.1 markus 274: mac->name = name;
275: mac->key = NULL;
276: mac->enabled = 0;
277: }
1.69 deraadt 278:
1.35 itojun 279: static void
1.1 markus 280: choose_comp(Comp *comp, char *client, char *server)
281: {
1.23 markus 282: char *name = match_list(client, server, NULL);
1.1 markus 283: if (name == NULL)
284: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 285: if (strcmp(name, "zlib@openssh.com") == 0) {
286: comp->type = COMP_DELAYED;
287: } else if (strcmp(name, "zlib") == 0) {
288: comp->type = COMP_ZLIB;
1.1 markus 289: } else if (strcmp(name, "none") == 0) {
1.64 markus 290: comp->type = COMP_NONE;
1.1 markus 291: } else {
292: fatal("unsupported comp %s", name);
293: }
294: comp->name = name;
295: }
1.69 deraadt 296:
1.35 itojun 297: static void
1.1 markus 298: choose_kex(Kex *k, char *client, char *server)
299: {
1.23 markus 300: k->name = match_list(client, server, NULL);
1.1 markus 301: if (k->name == NULL)
1.78 djm 302: fatal("Unable to negotiate a key exchange method");
1.11 provos 303: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 304: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 305: k->evp_md = EVP_sha1();
1.59 djm 306: } else if (strcmp(k->name, KEX_DH14) == 0) {
307: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 308: k->evp_md = EVP_sha1();
309: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 310: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 311: k->evp_md = EVP_sha1();
1.66 djm 312: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
313: k->kex_type = KEX_DH_GEX_SHA256;
1.80 djm 314: k->evp_md = EVP_sha256();
1.11 provos 315: } else
1.1 markus 316: fatal("bad kex alg %s", k->name);
317: }
1.65 djm 318:
1.35 itojun 319: static void
1.1 markus 320: choose_hostkeyalg(Kex *k, char *client, char *server)
321: {
1.23 markus 322: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 323: if (hostkeyalg == NULL)
1.1 markus 324: fatal("no hostkey alg");
1.13 markus 325: k->hostkey_type = key_type_from_name(hostkeyalg);
326: if (k->hostkey_type == KEY_UNSPEC)
327: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 328: xfree(hostkeyalg);
1.1 markus 329: }
330:
1.56 djm 331: static int
1.53 markus 332: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
333: {
334: static int check[] = {
335: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
336: };
337: int *idx;
338: char *p;
339:
340: for (idx = &check[0]; *idx != -1; idx++) {
341: if ((p = strchr(my[*idx], ',')) != NULL)
342: *p = '\0';
343: if ((p = strchr(peer[*idx], ',')) != NULL)
344: *p = '\0';
345: if (strcmp(my[*idx], peer[*idx]) != 0) {
346: debug2("proposal mismatch: my %s peer %s",
347: my[*idx], peer[*idx]);
348: return (0);
349: }
350: }
351: debug2("proposals match");
352: return (1);
353: }
354:
1.35 itojun 355: static void
1.27 markus 356: kex_choose_conf(Kex *kex)
1.1 markus 357: {
1.27 markus 358: Newkeys *newkeys;
1.26 markus 359: char **my, **peer;
360: char **cprop, **sprop;
1.27 markus 361: int nenc, nmac, ncomp;
1.61 djm 362: u_int mode, ctos, need;
1.53 markus 363: int first_kex_follows, type;
1.1 markus 364:
1.53 markus 365: my = kex_buf2prop(&kex->my, NULL);
366: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 367:
1.27 markus 368: if (kex->server) {
1.26 markus 369: cprop=peer;
370: sprop=my;
371: } else {
372: cprop=my;
373: sprop=peer;
374: }
1.1 markus 375:
1.30 markus 376: /* Algorithm Negotiation */
1.1 markus 377: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 djm 378: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 379: kex->newkeys[mode] = newkeys;
1.78 djm 380: ctos = (!kex->server && mode == MODE_OUT) ||
381: (kex->server && mode == MODE_IN);
1.1 markus 382: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
383: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
384: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 385: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
386: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
387: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 388: debug("kex: %s %s %s %s",
1.1 markus 389: ctos ? "client->server" : "server->client",
1.27 markus 390: newkeys->enc.name,
391: newkeys->mac.name,
392: newkeys->comp.name);
1.1 markus 393: }
1.27 markus 394: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
395: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 396: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
397: need = 0;
398: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 399: newkeys = kex->newkeys[mode];
1.45 markus 400: if (need < newkeys->enc.key_len)
401: need = newkeys->enc.key_len;
402: if (need < newkeys->enc.block_size)
403: need = newkeys->enc.block_size;
1.27 markus 404: if (need < newkeys->mac.key_len)
405: need = newkeys->mac.key_len;
1.1 markus 406: }
1.7 markus 407: /* XXX need runden? */
1.27 markus 408: kex->we_need = need;
1.53 markus 409:
410: /* ignore the next message if the proposals do not match */
1.56 djm 411: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 412: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 413: type = packet_read();
414: debug2("skipping next packet (type %u)", type);
415: }
1.26 markus 416:
417: kex_prop_free(my);
418: kex_prop_free(peer);
419: }
420:
1.35 itojun 421: static u_char *
1.65 djm 422: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
423: BIGNUM *shared_secret)
1.26 markus 424: {
425: Buffer b;
426: EVP_MD_CTX md;
427: char c = id;
1.61 djm 428: u_int have;
1.65 djm 429: int mdsz;
1.61 djm 430: u_char *digest;
1.62 djm 431:
1.65 djm 432: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
433: fatal("bad kex md size %d", mdsz);
1.68 deraadt 434: digest = xmalloc(roundup(need, mdsz));
1.26 markus 435:
436: buffer_init(&b);
437: buffer_put_bignum2(&b, shared_secret);
438:
1.30 markus 439: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 440: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 441: if (!(datafellows & SSH_BUG_DERIVEKEY))
442: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 443: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 444: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 445: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 446: EVP_DigestFinal(&md, digest, NULL);
447:
1.30 markus 448: /*
449: * expand key:
450: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
451: * Key = K1 || K2 || ... || Kn
452: */
1.26 markus 453: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 454: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 455: if (!(datafellows & SSH_BUG_DERIVEKEY))
456: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 457: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 458: EVP_DigestUpdate(&md, digest, have);
459: EVP_DigestFinal(&md, digest + have, NULL);
460: }
461: buffer_free(&b);
462: #ifdef DEBUG_KEX
463: fprintf(stderr, "key '%c'== ", c);
464: dump_digest("key", digest, need);
465: #endif
466: return digest;
1.1 markus 467: }
468:
1.30 markus 469: Newkeys *current_keys[MODE_MAX];
1.27 markus 470:
1.23 markus 471: #define NKEYS 6
1.26 markus 472: void
1.65 djm 473: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 474: {
1.15 markus 475: u_char *keys[NKEYS];
1.61 djm 476: u_int i, mode, ctos;
1.1 markus 477:
1.65 djm 478: for (i = 0; i < NKEYS; i++) {
479: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
480: shared_secret);
481: }
1.1 markus 482:
1.52 markus 483: debug2("kex_derive_keys");
1.1 markus 484: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 485: current_keys[mode] = kex->newkeys[mode];
486: kex->newkeys[mode] = NULL;
1.69 deraadt 487: ctos = (!kex->server && mode == MODE_OUT) ||
488: (kex->server && mode == MODE_IN);
1.30 markus 489: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
490: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
491: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 492: }
1.27 markus 493: }
494:
495: Newkeys *
496: kex_get_newkeys(int mode)
497: {
1.30 markus 498: Newkeys *ret;
499:
500: ret = current_keys[mode];
501: current_keys[mode] = NULL;
502: return ret;
1.57 djm 503: }
504:
505: void
506: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
507: u_int8_t cookie[8], u_int8_t id[16])
508: {
509: const EVP_MD *evp_md = EVP_md5();
510: EVP_MD_CTX md;
511: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
512: int len;
513:
514: EVP_DigestInit(&md, evp_md);
515:
516: len = BN_num_bytes(host_modulus);
1.61 djm 517: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 518: fatal("%s: bad host modulus (len %d)", __func__, len);
519: BN_bn2bin(host_modulus, nbuf);
520: EVP_DigestUpdate(&md, nbuf, len);
521:
522: len = BN_num_bytes(server_modulus);
1.61 djm 523: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 524: fatal("%s: bad server modulus (len %d)", __func__, len);
525: BN_bn2bin(server_modulus, nbuf);
526: EVP_DigestUpdate(&md, nbuf, len);
527:
528: EVP_DigestUpdate(&md, cookie, 8);
529:
1.58 djm 530: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 531: memcpy(id, obuf, 16);
532:
533: memset(nbuf, 0, sizeof(nbuf));
534: memset(obuf, 0, sizeof(obuf));
535: memset(&md, 0, sizeof(md));
1.1 markus 536: }
1.26 markus 537:
538: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
539: void
540: dump_digest(char *msg, u_char *digest, int len)
541: {
1.61 djm 542: u_int i;
1.26 markus 543:
544: fprintf(stderr, "%s\n", msg);
1.77 stevesk 545: for (i = 0; i < len; i++) {
1.26 markus 546: fprintf(stderr, "%02x", digest[i]);
547: if (i%32 == 31)
548: fprintf(stderr, "\n");
549: else if (i%8 == 7)
550: fprintf(stderr, " ");
551: }
552: fprintf(stderr, "\n");
553: }
554: #endif
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