Annotation of src/usr.bin/ssh/kex.c, Revision 1.76
1.76 ! deraadt 1: /* $OpenBSD: kex.c,v 1.75 2006/08/01 23:22:47 stevesk 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:
1.66 djm 51: extern const EVP_MD *evp_ssh_sha256(void);
52:
1.35 itojun 53: /* prototype */
54: static void kex_kexinit_finish(Kex *);
55: static void kex_choose_conf(Kex *);
1.26 markus 56:
57: /* put algorithm proposal into buffer */
1.35 itojun 58: static void
1.26 markus 59: kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
1.1 markus 60: {
1.61 djm 61: u_int i;
1.26 markus 62:
63: buffer_clear(b);
1.49 markus 64: /*
65: * add a dummy cookie, the cookie will be overwritten by
66: * kex_send_kexinit(), each time a kexinit is set
67: */
68: for (i = 0; i < KEX_COOKIE_LEN; i++)
69: buffer_put_char(b, 0);
1.1 markus 70: for (i = 0; i < PROPOSAL_MAX; i++)
1.26 markus 71: buffer_put_cstring(b, proposal[i]);
72: buffer_put_char(b, 0); /* first_kex_packet_follows */
73: buffer_put_int(b, 0); /* uint32 reserved */
1.1 markus 74: }
75:
1.26 markus 76: /* parse buffer and return algorithm proposal */
1.35 itojun 77: static char **
1.53 markus 78: kex_buf2prop(Buffer *raw, int *first_kex_follows)
1.7 markus 79: {
1.26 markus 80: Buffer b;
1.7 markus 81: int i;
1.26 markus 82: char **proposal;
1.7 markus 83:
1.70 djm 84: proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
1.7 markus 85:
1.26 markus 86: buffer_init(&b);
87: buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
1.7 markus 88: /* skip cookie */
89: for (i = 0; i < KEX_COOKIE_LEN; i++)
1.26 markus 90: buffer_get_char(&b);
1.7 markus 91: /* extract kex init proposal strings */
92: for (i = 0; i < PROPOSAL_MAX; i++) {
1.26 markus 93: proposal[i] = buffer_get_string(&b,NULL);
94: debug2("kex_parse_kexinit: %s", proposal[i]);
1.7 markus 95: }
1.26 markus 96: /* first kex follows / reserved */
97: i = buffer_get_char(&b);
1.53 markus 98: if (first_kex_follows != NULL)
99: *first_kex_follows = i;
1.26 markus 100: debug2("kex_parse_kexinit: first_kex_follows %d ", i);
101: i = buffer_get_int(&b);
102: debug2("kex_parse_kexinit: reserved %d ", i);
103: buffer_free(&b);
104: return proposal;
1.1 markus 105: }
106:
1.35 itojun 107: static void
1.26 markus 108: kex_prop_free(char **proposal)
1.1 markus 109: {
1.61 djm 110: u_int i;
1.26 markus 111:
112: for (i = 0; i < PROPOSAL_MAX; i++)
113: xfree(proposal[i]);
114: xfree(proposal);
1.1 markus 115: }
116:
1.35 itojun 117: static void
1.41 markus 118: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 119: {
1.41 markus 120: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 121: }
1.1 markus 122:
1.35 itojun 123: static void
1.44 markus 124: kex_reset_dispatch(void)
1.29 markus 125: {
1.42 markus 126: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
127: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 128: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 129: }
130:
131: void
1.28 markus 132: kex_finish(Kex *kex)
1.26 markus 133: {
1.44 markus 134: kex_reset_dispatch();
1.28 markus 135:
1.26 markus 136: packet_start(SSH2_MSG_NEWKEYS);
137: packet_send();
138: /* packet_write_wait(); */
139: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 140:
1.52 markus 141: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 142: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 143: packet_check_eom();
1.26 markus 144: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 145:
1.30 markus 146: kex->done = 1;
1.26 markus 147: buffer_clear(&kex->peer);
1.27 markus 148: /* buffer_clear(&kex->my); */
1.26 markus 149: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 150: xfree(kex->name);
151: kex->name = NULL;
1.26 markus 152: }
1.1 markus 153:
1.26 markus 154: void
155: kex_send_kexinit(Kex *kex)
156: {
1.60 avsm 157: u_int32_t rnd = 0;
1.49 markus 158: u_char *cookie;
1.61 djm 159: u_int i;
1.49 markus 160:
1.29 markus 161: if (kex == NULL) {
162: error("kex_send_kexinit: no kex, cannot rekey");
163: return;
164: }
1.28 markus 165: if (kex->flags & KEX_INIT_SENT) {
166: debug("KEX_INIT_SENT");
167: return;
168: }
1.30 markus 169: kex->done = 0;
1.49 markus 170:
171: /* generate a random cookie */
172: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
173: fatal("kex_send_kexinit: kex proposal too short");
174: cookie = buffer_ptr(&kex->my);
175: for (i = 0; i < KEX_COOKIE_LEN; i++) {
176: if (i % 4 == 0)
1.60 avsm 177: rnd = arc4random();
178: cookie[i] = rnd;
179: rnd >>= 8;
1.49 markus 180: }
1.26 markus 181: packet_start(SSH2_MSG_KEXINIT);
182: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
183: packet_send();
184: debug("SSH2_MSG_KEXINIT sent");
185: kex->flags |= KEX_INIT_SENT;
1.1 markus 186: }
187:
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)
252: fatal("no matching cipher found: client %s server %s", client, server);
1.45 markus 253: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 254: fatal("matching cipher is not supported: %s", name);
1.1 markus 255: enc->name = name;
256: enc->enabled = 0;
257: enc->iv = NULL;
258: enc->key = NULL;
1.45 markus 259: enc->key_len = cipher_keylen(enc->cipher);
260: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 261: }
1.69 deraadt 262:
1.35 itojun 263: static void
1.1 markus 264: choose_mac(Mac *mac, char *client, char *server)
265: {
1.23 markus 266: char *name = match_list(client, server, NULL);
1.1 markus 267: if (name == NULL)
268: fatal("no matching mac found: client %s server %s", client, server);
1.21 markus 269: if (mac_init(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)
302: fatal("no kex alg");
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;
314: k->evp_md = evp_ssh_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;
1.27 markus 380: ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
1.1 markus 381: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
382: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
383: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 384: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
385: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
386: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 387: debug("kex: %s %s %s %s",
1.1 markus 388: ctos ? "client->server" : "server->client",
1.27 markus 389: newkeys->enc.name,
390: newkeys->mac.name,
391: newkeys->comp.name);
1.1 markus 392: }
1.27 markus 393: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
394: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 395: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
396: need = 0;
397: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 398: newkeys = kex->newkeys[mode];
1.45 markus 399: if (need < newkeys->enc.key_len)
400: need = newkeys->enc.key_len;
401: if (need < newkeys->enc.block_size)
402: need = newkeys->enc.block_size;
1.27 markus 403: if (need < newkeys->mac.key_len)
404: need = newkeys->mac.key_len;
1.1 markus 405: }
1.7 markus 406: /* XXX need runden? */
1.27 markus 407: kex->we_need = need;
1.53 markus 408:
409: /* ignore the next message if the proposals do not match */
1.56 djm 410: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 411: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 412: type = packet_read();
413: debug2("skipping next packet (type %u)", type);
414: }
1.26 markus 415:
416: kex_prop_free(my);
417: kex_prop_free(peer);
418: }
419:
1.35 itojun 420: static u_char *
1.65 djm 421: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
422: BIGNUM *shared_secret)
1.26 markus 423: {
424: Buffer b;
425: EVP_MD_CTX md;
426: char c = id;
1.61 djm 427: u_int have;
1.65 djm 428: int mdsz;
1.61 djm 429: u_char *digest;
1.62 djm 430:
1.65 djm 431: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
432: fatal("bad kex md size %d", mdsz);
1.68 deraadt 433: digest = xmalloc(roundup(need, mdsz));
1.26 markus 434:
435: buffer_init(&b);
436: buffer_put_bignum2(&b, shared_secret);
437:
1.30 markus 438: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 439: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 440: if (!(datafellows & SSH_BUG_DERIVEKEY))
441: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 442: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 443: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 444: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 445: EVP_DigestFinal(&md, digest, NULL);
446:
1.30 markus 447: /*
448: * expand key:
449: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
450: * Key = K1 || K2 || ... || Kn
451: */
1.26 markus 452: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 453: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 454: if (!(datafellows & SSH_BUG_DERIVEKEY))
455: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 456: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 457: EVP_DigestUpdate(&md, digest, have);
458: EVP_DigestFinal(&md, digest + have, NULL);
459: }
460: buffer_free(&b);
461: #ifdef DEBUG_KEX
462: fprintf(stderr, "key '%c'== ", c);
463: dump_digest("key", digest, need);
464: #endif
465: return digest;
1.1 markus 466: }
467:
1.30 markus 468: Newkeys *current_keys[MODE_MAX];
1.27 markus 469:
1.23 markus 470: #define NKEYS 6
1.26 markus 471: void
1.65 djm 472: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 473: {
1.15 markus 474: u_char *keys[NKEYS];
1.61 djm 475: u_int i, mode, ctos;
1.1 markus 476:
1.65 djm 477: for (i = 0; i < NKEYS; i++) {
478: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
479: shared_secret);
480: }
1.1 markus 481:
1.52 markus 482: debug2("kex_derive_keys");
1.1 markus 483: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 484: current_keys[mode] = kex->newkeys[mode];
485: kex->newkeys[mode] = NULL;
1.69 deraadt 486: ctos = (!kex->server && mode == MODE_OUT) ||
487: (kex->server && mode == MODE_IN);
1.30 markus 488: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
489: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
490: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 491: }
1.27 markus 492: }
493:
494: Newkeys *
495: kex_get_newkeys(int mode)
496: {
1.30 markus 497: Newkeys *ret;
498:
499: ret = current_keys[mode];
500: current_keys[mode] = NULL;
501: return ret;
1.57 djm 502: }
503:
504: void
505: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
506: u_int8_t cookie[8], u_int8_t id[16])
507: {
508: const EVP_MD *evp_md = EVP_md5();
509: EVP_MD_CTX md;
510: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
511: int len;
512:
513: EVP_DigestInit(&md, evp_md);
514:
515: len = BN_num_bytes(host_modulus);
1.61 djm 516: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 517: fatal("%s: bad host modulus (len %d)", __func__, len);
518: BN_bn2bin(host_modulus, nbuf);
519: EVP_DigestUpdate(&md, nbuf, len);
520:
521: len = BN_num_bytes(server_modulus);
1.61 djm 522: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 523: fatal("%s: bad server modulus (len %d)", __func__, len);
524: BN_bn2bin(server_modulus, nbuf);
525: EVP_DigestUpdate(&md, nbuf, len);
526:
527: EVP_DigestUpdate(&md, cookie, 8);
528:
1.58 djm 529: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 530: memcpy(id, obuf, 16);
531:
532: memset(nbuf, 0, sizeof(nbuf));
533: memset(obuf, 0, sizeof(obuf));
534: memset(&md, 0, sizeof(md));
1.1 markus 535: }
1.26 markus 536:
537: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
538: void
539: dump_digest(char *msg, u_char *digest, int len)
540: {
1.61 djm 541: u_int i;
1.26 markus 542:
543: fprintf(stderr, "%s\n", msg);
1.37 deraadt 544: for (i = 0; i< len; i++) {
1.26 markus 545: fprintf(stderr, "%02x", digest[i]);
546: if (i%32 == 31)
547: fprintf(stderr, "\n");
548: else if (i%8 == 7)
549: fprintf(stderr, " ");
550: }
551: fprintf(stderr, "\n");
552: }
553: #endif
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