Annotation of src/usr.bin/ssh/kex.c, Revision 1.78
1.78 ! djm 1: /* $OpenBSD: kex.c,v 1.77 2007/01/21 01:41:54 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;
1.78 ! djm 81: u_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);
1.78 ! djm 102: debug2("kex_parse_kexinit: reserved %u ", i);
1.26 markus 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:
1.78 ! djm 117: /* ARGSUSED */
1.35 itojun 118: static void
1.41 markus 119: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 120: {
1.41 markus 121: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 122: }
1.1 markus 123:
1.35 itojun 124: static void
1.44 markus 125: kex_reset_dispatch(void)
1.29 markus 126: {
1.42 markus 127: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
128: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 129: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 130: }
131:
132: void
1.28 markus 133: kex_finish(Kex *kex)
1.26 markus 134: {
1.44 markus 135: kex_reset_dispatch();
1.28 markus 136:
1.26 markus 137: packet_start(SSH2_MSG_NEWKEYS);
138: packet_send();
139: /* packet_write_wait(); */
140: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 141:
1.52 markus 142: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 143: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 144: packet_check_eom();
1.26 markus 145: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 146:
1.30 markus 147: kex->done = 1;
1.26 markus 148: buffer_clear(&kex->peer);
1.27 markus 149: /* buffer_clear(&kex->my); */
1.26 markus 150: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 151: xfree(kex->name);
152: kex->name = NULL;
1.26 markus 153: }
1.1 markus 154:
1.26 markus 155: void
156: kex_send_kexinit(Kex *kex)
157: {
1.60 avsm 158: u_int32_t rnd = 0;
1.49 markus 159: u_char *cookie;
1.61 djm 160: u_int i;
1.49 markus 161:
1.29 markus 162: if (kex == NULL) {
163: error("kex_send_kexinit: no kex, cannot rekey");
164: return;
165: }
1.28 markus 166: if (kex->flags & KEX_INIT_SENT) {
167: debug("KEX_INIT_SENT");
168: return;
169: }
1.30 markus 170: kex->done = 0;
1.49 markus 171:
172: /* generate a random cookie */
173: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
174: fatal("kex_send_kexinit: kex proposal too short");
175: cookie = buffer_ptr(&kex->my);
176: for (i = 0; i < KEX_COOKIE_LEN; i++) {
177: if (i % 4 == 0)
1.60 avsm 178: rnd = arc4random();
179: cookie[i] = rnd;
180: rnd >>= 8;
1.49 markus 181: }
1.26 markus 182: packet_start(SSH2_MSG_KEXINIT);
183: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
184: packet_send();
185: debug("SSH2_MSG_KEXINIT sent");
186: kex->flags |= KEX_INIT_SENT;
1.1 markus 187: }
188:
1.78 ! djm 189: /* ARGSUSED */
1.26 markus 190: void
1.41 markus 191: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 192: {
1.26 markus 193: char *ptr;
1.61 djm 194: u_int i, dlen;
1.26 markus 195: Kex *kex = (Kex *)ctxt;
1.11 provos 196:
1.26 markus 197: debug("SSH2_MSG_KEXINIT received");
1.29 markus 198: if (kex == NULL)
199: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 200:
1.26 markus 201: ptr = packet_get_raw(&dlen);
202: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 203:
204: /* discard packet */
205: for (i = 0; i < KEX_COOKIE_LEN; i++)
206: packet_get_char();
207: for (i = 0; i < PROPOSAL_MAX; i++)
208: xfree(packet_get_string(NULL));
1.51 markus 209: (void) packet_get_char();
210: (void) packet_get_int();
1.39 markus 211: packet_check_eom();
1.19 stevesk 212:
1.26 markus 213: kex_kexinit_finish(kex);
214: }
1.11 provos 215:
1.26 markus 216: Kex *
1.28 markus 217: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 218: {
219: Kex *kex;
1.11 provos 220:
1.70 djm 221: kex = xcalloc(1, sizeof(*kex));
1.26 markus 222: buffer_init(&kex->peer);
223: buffer_init(&kex->my);
224: kex_prop2buf(&kex->my, proposal);
1.30 markus 225: kex->done = 0;
1.26 markus 226:
227: kex_send_kexinit(kex); /* we start */
1.44 markus 228: kex_reset_dispatch();
1.26 markus 229:
230: return kex;
1.11 provos 231: }
232:
1.35 itojun 233: static void
1.26 markus 234: kex_kexinit_finish(Kex *kex)
1.1 markus 235: {
1.26 markus 236: if (!(kex->flags & KEX_INIT_SENT))
237: kex_send_kexinit(kex);
1.1 markus 238:
1.26 markus 239: kex_choose_conf(kex);
1.1 markus 240:
1.54 markus 241: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
242: kex->kex[kex->kex_type] != NULL) {
243: (kex->kex[kex->kex_type])(kex);
244: } else {
1.26 markus 245: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 246: }
247: }
248:
1.35 itojun 249: static void
1.1 markus 250: choose_enc(Enc *enc, char *client, char *server)
251: {
1.23 markus 252: char *name = match_list(client, server, NULL);
1.1 markus 253: if (name == NULL)
1.78 ! djm 254: fatal("no matching cipher found: client %s server %s",
! 255: client, server);
1.45 markus 256: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 257: fatal("matching cipher is not supported: %s", name);
1.1 markus 258: enc->name = name;
259: enc->enabled = 0;
260: enc->iv = NULL;
261: enc->key = NULL;
1.45 markus 262: enc->key_len = cipher_keylen(enc->cipher);
263: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 264: }
1.69 deraadt 265:
1.35 itojun 266: static void
1.1 markus 267: choose_mac(Mac *mac, char *client, char *server)
268: {
1.23 markus 269: char *name = match_list(client, server, NULL);
1.1 markus 270: if (name == NULL)
1.78 ! djm 271: fatal("no matching mac found: client %s server %s",
! 272: client, server);
1.21 markus 273: if (mac_init(mac, name) < 0)
1.1 markus 274: fatal("unsupported mac %s", name);
1.21 markus 275: /* truncate the key */
276: if (datafellows & SSH_BUG_HMAC)
277: mac->key_len = 16;
1.1 markus 278: mac->name = name;
279: mac->key = NULL;
280: mac->enabled = 0;
281: }
1.69 deraadt 282:
1.35 itojun 283: static void
1.1 markus 284: choose_comp(Comp *comp, char *client, char *server)
285: {
1.23 markus 286: char *name = match_list(client, server, NULL);
1.1 markus 287: if (name == NULL)
288: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 289: if (strcmp(name, "zlib@openssh.com") == 0) {
290: comp->type = COMP_DELAYED;
291: } else if (strcmp(name, "zlib") == 0) {
292: comp->type = COMP_ZLIB;
1.1 markus 293: } else if (strcmp(name, "none") == 0) {
1.64 markus 294: comp->type = COMP_NONE;
1.1 markus 295: } else {
296: fatal("unsupported comp %s", name);
297: }
298: comp->name = name;
299: }
1.69 deraadt 300:
1.35 itojun 301: static void
1.1 markus 302: choose_kex(Kex *k, char *client, char *server)
303: {
1.23 markus 304: k->name = match_list(client, server, NULL);
1.1 markus 305: if (k->name == NULL)
1.78 ! djm 306: fatal("Unable to negotiate a key exchange method");
1.11 provos 307: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 308: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 309: k->evp_md = EVP_sha1();
1.59 djm 310: } else if (strcmp(k->name, KEX_DH14) == 0) {
311: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 312: k->evp_md = EVP_sha1();
313: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 314: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 315: k->evp_md = EVP_sha1();
1.66 djm 316: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
317: k->kex_type = KEX_DH_GEX_SHA256;
318: k->evp_md = evp_ssh_sha256();
1.11 provos 319: } else
1.1 markus 320: fatal("bad kex alg %s", k->name);
321: }
1.65 djm 322:
1.35 itojun 323: static void
1.1 markus 324: choose_hostkeyalg(Kex *k, char *client, char *server)
325: {
1.23 markus 326: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 327: if (hostkeyalg == NULL)
1.1 markus 328: fatal("no hostkey alg");
1.13 markus 329: k->hostkey_type = key_type_from_name(hostkeyalg);
330: if (k->hostkey_type == KEY_UNSPEC)
331: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 332: xfree(hostkeyalg);
1.1 markus 333: }
334:
1.56 djm 335: static int
1.53 markus 336: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
337: {
338: static int check[] = {
339: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
340: };
341: int *idx;
342: char *p;
343:
344: for (idx = &check[0]; *idx != -1; idx++) {
345: if ((p = strchr(my[*idx], ',')) != NULL)
346: *p = '\0';
347: if ((p = strchr(peer[*idx], ',')) != NULL)
348: *p = '\0';
349: if (strcmp(my[*idx], peer[*idx]) != 0) {
350: debug2("proposal mismatch: my %s peer %s",
351: my[*idx], peer[*idx]);
352: return (0);
353: }
354: }
355: debug2("proposals match");
356: return (1);
357: }
358:
1.35 itojun 359: static void
1.27 markus 360: kex_choose_conf(Kex *kex)
1.1 markus 361: {
1.27 markus 362: Newkeys *newkeys;
1.26 markus 363: char **my, **peer;
364: char **cprop, **sprop;
1.27 markus 365: int nenc, nmac, ncomp;
1.61 djm 366: u_int mode, ctos, need;
1.53 markus 367: int first_kex_follows, type;
1.1 markus 368:
1.53 markus 369: my = kex_buf2prop(&kex->my, NULL);
370: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 371:
1.27 markus 372: if (kex->server) {
1.26 markus 373: cprop=peer;
374: sprop=my;
375: } else {
376: cprop=my;
377: sprop=peer;
378: }
1.1 markus 379:
1.30 markus 380: /* Algorithm Negotiation */
1.1 markus 381: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 djm 382: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 383: kex->newkeys[mode] = newkeys;
1.78 ! djm 384: ctos = (!kex->server && mode == MODE_OUT) ||
! 385: (kex->server && mode == MODE_IN);
1.1 markus 386: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
387: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
388: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 389: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
390: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
391: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 392: debug("kex: %s %s %s %s",
1.1 markus 393: ctos ? "client->server" : "server->client",
1.27 markus 394: newkeys->enc.name,
395: newkeys->mac.name,
396: newkeys->comp.name);
1.1 markus 397: }
1.27 markus 398: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
399: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 400: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
401: need = 0;
402: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 403: newkeys = kex->newkeys[mode];
1.45 markus 404: if (need < newkeys->enc.key_len)
405: need = newkeys->enc.key_len;
406: if (need < newkeys->enc.block_size)
407: need = newkeys->enc.block_size;
1.27 markus 408: if (need < newkeys->mac.key_len)
409: need = newkeys->mac.key_len;
1.1 markus 410: }
1.7 markus 411: /* XXX need runden? */
1.27 markus 412: kex->we_need = need;
1.53 markus 413:
414: /* ignore the next message if the proposals do not match */
1.56 djm 415: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 416: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 417: type = packet_read();
418: debug2("skipping next packet (type %u)", type);
419: }
1.26 markus 420:
421: kex_prop_free(my);
422: kex_prop_free(peer);
423: }
424:
1.35 itojun 425: static u_char *
1.65 djm 426: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
427: BIGNUM *shared_secret)
1.26 markus 428: {
429: Buffer b;
430: EVP_MD_CTX md;
431: char c = id;
1.61 djm 432: u_int have;
1.65 djm 433: int mdsz;
1.61 djm 434: u_char *digest;
1.62 djm 435:
1.65 djm 436: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
437: fatal("bad kex md size %d", mdsz);
1.68 deraadt 438: digest = xmalloc(roundup(need, mdsz));
1.26 markus 439:
440: buffer_init(&b);
441: buffer_put_bignum2(&b, shared_secret);
442:
1.30 markus 443: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 444: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 445: if (!(datafellows & SSH_BUG_DERIVEKEY))
446: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 447: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 448: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 449: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 450: EVP_DigestFinal(&md, digest, NULL);
451:
1.30 markus 452: /*
453: * expand key:
454: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
455: * Key = K1 || K2 || ... || Kn
456: */
1.26 markus 457: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 458: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 459: if (!(datafellows & SSH_BUG_DERIVEKEY))
460: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 461: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 462: EVP_DigestUpdate(&md, digest, have);
463: EVP_DigestFinal(&md, digest + have, NULL);
464: }
465: buffer_free(&b);
466: #ifdef DEBUG_KEX
467: fprintf(stderr, "key '%c'== ", c);
468: dump_digest("key", digest, need);
469: #endif
470: return digest;
1.1 markus 471: }
472:
1.30 markus 473: Newkeys *current_keys[MODE_MAX];
1.27 markus 474:
1.23 markus 475: #define NKEYS 6
1.26 markus 476: void
1.65 djm 477: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 478: {
1.15 markus 479: u_char *keys[NKEYS];
1.61 djm 480: u_int i, mode, ctos;
1.1 markus 481:
1.65 djm 482: for (i = 0; i < NKEYS; i++) {
483: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
484: shared_secret);
485: }
1.1 markus 486:
1.52 markus 487: debug2("kex_derive_keys");
1.1 markus 488: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 489: current_keys[mode] = kex->newkeys[mode];
490: kex->newkeys[mode] = NULL;
1.69 deraadt 491: ctos = (!kex->server && mode == MODE_OUT) ||
492: (kex->server && mode == MODE_IN);
1.30 markus 493: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
494: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
495: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 496: }
1.27 markus 497: }
498:
499: Newkeys *
500: kex_get_newkeys(int mode)
501: {
1.30 markus 502: Newkeys *ret;
503:
504: ret = current_keys[mode];
505: current_keys[mode] = NULL;
506: return ret;
1.57 djm 507: }
508:
509: void
510: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
511: u_int8_t cookie[8], u_int8_t id[16])
512: {
513: const EVP_MD *evp_md = EVP_md5();
514: EVP_MD_CTX md;
515: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
516: int len;
517:
518: EVP_DigestInit(&md, evp_md);
519:
520: len = BN_num_bytes(host_modulus);
1.61 djm 521: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 522: fatal("%s: bad host modulus (len %d)", __func__, len);
523: BN_bn2bin(host_modulus, nbuf);
524: EVP_DigestUpdate(&md, nbuf, len);
525:
526: len = BN_num_bytes(server_modulus);
1.61 djm 527: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 528: fatal("%s: bad server modulus (len %d)", __func__, len);
529: BN_bn2bin(server_modulus, nbuf);
530: EVP_DigestUpdate(&md, nbuf, len);
531:
532: EVP_DigestUpdate(&md, cookie, 8);
533:
1.58 djm 534: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 535: memcpy(id, obuf, 16);
536:
537: memset(nbuf, 0, sizeof(nbuf));
538: memset(obuf, 0, sizeof(obuf));
539: memset(&md, 0, sizeof(md));
1.1 markus 540: }
1.26 markus 541:
542: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
543: void
544: dump_digest(char *msg, u_char *digest, int len)
545: {
1.61 djm 546: u_int i;
1.26 markus 547:
548: fprintf(stderr, "%s\n", msg);
1.77 stevesk 549: for (i = 0; i < len; i++) {
1.26 markus 550: fprintf(stderr, "%02x", digest[i]);
551: if (i%32 == 31)
552: fprintf(stderr, "\n");
553: else if (i%8 == 7)
554: fprintf(stderr, " ");
555: }
556: fprintf(stderr, "\n");
557: }
558: #endif
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