Annotation of src/usr.bin/ssh/kex.c, Revision 1.71
1.71 ! djm 1: /* $OpenBSD$ */
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:
26: #include "includes.h"
1.18 markus 27:
28: #include <openssl/crypto.h>
1.1 markus 29:
30: #include "ssh2.h"
31: #include "xmalloc.h"
32: #include "buffer.h"
33: #include "bufaux.h"
1.7 markus 34: #include "packet.h"
1.1 markus 35: #include "compat.h"
1.18 markus 36: #include "cipher.h"
1.1 markus 37: #include "kex.h"
1.13 markus 38: #include "key.h"
1.18 markus 39: #include "log.h"
1.21 markus 40: #include "mac.h"
1.23 markus 41: #include "match.h"
1.26 markus 42: #include "dispatch.h"
1.48 provos 43: #include "monitor.h"
1.1 markus 44:
1.7 markus 45: #define KEX_COOKIE_LEN 16
1.48 provos 46:
1.66 djm 47: extern const EVP_MD *evp_ssh_sha256(void);
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;
1.7 markus 77: 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);
98: debug2("kex_parse_kexinit: reserved %d ", i);
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:
1.35 itojun 113: static void
1.41 markus 114: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 115: {
1.41 markus 116: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 117: }
1.1 markus 118:
1.35 itojun 119: static void
1.44 markus 120: kex_reset_dispatch(void)
1.29 markus 121: {
1.42 markus 122: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
123: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 124: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 125: }
126:
127: void
1.28 markus 128: kex_finish(Kex *kex)
1.26 markus 129: {
1.44 markus 130: kex_reset_dispatch();
1.28 markus 131:
1.26 markus 132: packet_start(SSH2_MSG_NEWKEYS);
133: packet_send();
134: /* packet_write_wait(); */
135: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 136:
1.52 markus 137: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 138: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 139: packet_check_eom();
1.26 markus 140: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 141:
1.30 markus 142: kex->done = 1;
1.26 markus 143: buffer_clear(&kex->peer);
1.27 markus 144: /* buffer_clear(&kex->my); */
1.26 markus 145: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 146: xfree(kex->name);
147: kex->name = NULL;
1.26 markus 148: }
1.1 markus 149:
1.26 markus 150: void
151: kex_send_kexinit(Kex *kex)
152: {
1.60 avsm 153: u_int32_t rnd = 0;
1.49 markus 154: u_char *cookie;
1.61 djm 155: u_int i;
1.49 markus 156:
1.29 markus 157: if (kex == NULL) {
158: error("kex_send_kexinit: no kex, cannot rekey");
159: return;
160: }
1.28 markus 161: if (kex->flags & KEX_INIT_SENT) {
162: debug("KEX_INIT_SENT");
163: return;
164: }
1.30 markus 165: kex->done = 0;
1.49 markus 166:
167: /* generate a random cookie */
168: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
169: fatal("kex_send_kexinit: kex proposal too short");
170: cookie = buffer_ptr(&kex->my);
171: for (i = 0; i < KEX_COOKIE_LEN; i++) {
172: if (i % 4 == 0)
1.60 avsm 173: rnd = arc4random();
174: cookie[i] = rnd;
175: rnd >>= 8;
1.49 markus 176: }
1.26 markus 177: packet_start(SSH2_MSG_KEXINIT);
178: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
179: packet_send();
180: debug("SSH2_MSG_KEXINIT sent");
181: kex->flags |= KEX_INIT_SENT;
1.1 markus 182: }
183:
1.26 markus 184: void
1.41 markus 185: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 186: {
1.26 markus 187: char *ptr;
1.61 djm 188: u_int i, dlen;
1.26 markus 189: Kex *kex = (Kex *)ctxt;
1.11 provos 190:
1.26 markus 191: debug("SSH2_MSG_KEXINIT received");
1.29 markus 192: if (kex == NULL)
193: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 194:
1.26 markus 195: ptr = packet_get_raw(&dlen);
196: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 197:
198: /* discard packet */
199: for (i = 0; i < KEX_COOKIE_LEN; i++)
200: packet_get_char();
201: for (i = 0; i < PROPOSAL_MAX; i++)
202: xfree(packet_get_string(NULL));
1.51 markus 203: (void) packet_get_char();
204: (void) packet_get_int();
1.39 markus 205: packet_check_eom();
1.19 stevesk 206:
1.26 markus 207: kex_kexinit_finish(kex);
208: }
1.11 provos 209:
1.26 markus 210: Kex *
1.28 markus 211: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 212: {
213: Kex *kex;
1.11 provos 214:
1.70 djm 215: kex = xcalloc(1, sizeof(*kex));
1.26 markus 216: buffer_init(&kex->peer);
217: buffer_init(&kex->my);
218: kex_prop2buf(&kex->my, proposal);
1.30 markus 219: kex->done = 0;
1.26 markus 220:
221: kex_send_kexinit(kex); /* we start */
1.44 markus 222: kex_reset_dispatch();
1.26 markus 223:
224: return kex;
1.11 provos 225: }
226:
1.35 itojun 227: static void
1.26 markus 228: kex_kexinit_finish(Kex *kex)
1.1 markus 229: {
1.26 markus 230: if (!(kex->flags & KEX_INIT_SENT))
231: kex_send_kexinit(kex);
1.1 markus 232:
1.26 markus 233: kex_choose_conf(kex);
1.1 markus 234:
1.54 markus 235: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
236: kex->kex[kex->kex_type] != NULL) {
237: (kex->kex[kex->kex_type])(kex);
238: } else {
1.26 markus 239: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 240: }
241: }
242:
1.35 itojun 243: static void
1.1 markus 244: choose_enc(Enc *enc, char *client, char *server)
245: {
1.23 markus 246: char *name = match_list(client, server, NULL);
1.1 markus 247: if (name == NULL)
248: fatal("no matching cipher found: client %s server %s", client, server);
1.45 markus 249: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 250: fatal("matching cipher is not supported: %s", name);
1.1 markus 251: enc->name = name;
252: enc->enabled = 0;
253: enc->iv = NULL;
254: enc->key = NULL;
1.45 markus 255: enc->key_len = cipher_keylen(enc->cipher);
256: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 257: }
1.69 deraadt 258:
1.35 itojun 259: static void
1.1 markus 260: choose_mac(Mac *mac, char *client, char *server)
261: {
1.23 markus 262: char *name = match_list(client, server, NULL);
1.1 markus 263: if (name == NULL)
264: fatal("no matching mac found: client %s server %s", client, server);
1.21 markus 265: if (mac_init(mac, name) < 0)
1.1 markus 266: fatal("unsupported mac %s", name);
1.21 markus 267: /* truncate the key */
268: if (datafellows & SSH_BUG_HMAC)
269: mac->key_len = 16;
1.1 markus 270: mac->name = name;
271: mac->key = NULL;
272: mac->enabled = 0;
273: }
1.69 deraadt 274:
1.35 itojun 275: static void
1.1 markus 276: choose_comp(Comp *comp, char *client, char *server)
277: {
1.23 markus 278: char *name = match_list(client, server, NULL);
1.1 markus 279: if (name == NULL)
280: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 281: if (strcmp(name, "zlib@openssh.com") == 0) {
282: comp->type = COMP_DELAYED;
283: } else if (strcmp(name, "zlib") == 0) {
284: comp->type = COMP_ZLIB;
1.1 markus 285: } else if (strcmp(name, "none") == 0) {
1.64 markus 286: comp->type = COMP_NONE;
1.1 markus 287: } else {
288: fatal("unsupported comp %s", name);
289: }
290: comp->name = name;
291: }
1.69 deraadt 292:
1.35 itojun 293: static void
1.1 markus 294: choose_kex(Kex *k, char *client, char *server)
295: {
1.23 markus 296: k->name = match_list(client, server, NULL);
1.1 markus 297: if (k->name == NULL)
298: fatal("no kex alg");
1.11 provos 299: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 300: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 301: k->evp_md = EVP_sha1();
1.59 djm 302: } else if (strcmp(k->name, KEX_DH14) == 0) {
303: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 304: k->evp_md = EVP_sha1();
305: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 306: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 307: k->evp_md = EVP_sha1();
1.66 djm 308: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
309: k->kex_type = KEX_DH_GEX_SHA256;
310: k->evp_md = evp_ssh_sha256();
1.11 provos 311: } else
1.1 markus 312: fatal("bad kex alg %s", k->name);
313: }
1.65 djm 314:
1.35 itojun 315: static void
1.1 markus 316: choose_hostkeyalg(Kex *k, char *client, char *server)
317: {
1.23 markus 318: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 319: if (hostkeyalg == NULL)
1.1 markus 320: fatal("no hostkey alg");
1.13 markus 321: k->hostkey_type = key_type_from_name(hostkeyalg);
322: if (k->hostkey_type == KEY_UNSPEC)
323: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 324: xfree(hostkeyalg);
1.1 markus 325: }
326:
1.56 djm 327: static int
1.53 markus 328: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
329: {
330: static int check[] = {
331: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
332: };
333: int *idx;
334: char *p;
335:
336: for (idx = &check[0]; *idx != -1; idx++) {
337: if ((p = strchr(my[*idx], ',')) != NULL)
338: *p = '\0';
339: if ((p = strchr(peer[*idx], ',')) != NULL)
340: *p = '\0';
341: if (strcmp(my[*idx], peer[*idx]) != 0) {
342: debug2("proposal mismatch: my %s peer %s",
343: my[*idx], peer[*idx]);
344: return (0);
345: }
346: }
347: debug2("proposals match");
348: return (1);
349: }
350:
1.35 itojun 351: static void
1.27 markus 352: kex_choose_conf(Kex *kex)
1.1 markus 353: {
1.27 markus 354: Newkeys *newkeys;
1.26 markus 355: char **my, **peer;
356: char **cprop, **sprop;
1.27 markus 357: int nenc, nmac, ncomp;
1.61 djm 358: u_int mode, ctos, need;
1.53 markus 359: int first_kex_follows, type;
1.1 markus 360:
1.53 markus 361: my = kex_buf2prop(&kex->my, NULL);
362: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 363:
1.27 markus 364: if (kex->server) {
1.26 markus 365: cprop=peer;
366: sprop=my;
367: } else {
368: cprop=my;
369: sprop=peer;
370: }
1.1 markus 371:
1.30 markus 372: /* Algorithm Negotiation */
1.1 markus 373: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 djm 374: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 375: kex->newkeys[mode] = newkeys;
1.27 markus 376: ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
1.1 markus 377: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
378: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
379: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 380: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
381: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
382: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 383: debug("kex: %s %s %s %s",
1.1 markus 384: ctos ? "client->server" : "server->client",
1.27 markus 385: newkeys->enc.name,
386: newkeys->mac.name,
387: newkeys->comp.name);
1.1 markus 388: }
1.27 markus 389: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
390: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 391: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
392: need = 0;
393: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 394: newkeys = kex->newkeys[mode];
1.45 markus 395: if (need < newkeys->enc.key_len)
396: need = newkeys->enc.key_len;
397: if (need < newkeys->enc.block_size)
398: need = newkeys->enc.block_size;
1.27 markus 399: if (need < newkeys->mac.key_len)
400: need = newkeys->mac.key_len;
1.1 markus 401: }
1.7 markus 402: /* XXX need runden? */
1.27 markus 403: kex->we_need = need;
1.53 markus 404:
405: /* ignore the next message if the proposals do not match */
1.56 djm 406: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 407: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 408: type = packet_read();
409: debug2("skipping next packet (type %u)", type);
410: }
1.26 markus 411:
412: kex_prop_free(my);
413: kex_prop_free(peer);
414: }
415:
1.35 itojun 416: static u_char *
1.65 djm 417: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
418: BIGNUM *shared_secret)
1.26 markus 419: {
420: Buffer b;
421: EVP_MD_CTX md;
422: char c = id;
1.61 djm 423: u_int have;
1.65 djm 424: int mdsz;
1.61 djm 425: u_char *digest;
1.62 djm 426:
1.65 djm 427: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
428: fatal("bad kex md size %d", mdsz);
1.68 deraadt 429: digest = xmalloc(roundup(need, mdsz));
1.26 markus 430:
431: buffer_init(&b);
432: buffer_put_bignum2(&b, shared_secret);
433:
1.30 markus 434: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 435: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 436: if (!(datafellows & SSH_BUG_DERIVEKEY))
437: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 438: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 439: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 440: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 441: EVP_DigestFinal(&md, digest, NULL);
442:
1.30 markus 443: /*
444: * expand key:
445: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
446: * Key = K1 || K2 || ... || Kn
447: */
1.26 markus 448: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 449: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 450: if (!(datafellows & SSH_BUG_DERIVEKEY))
451: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 452: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 453: EVP_DigestUpdate(&md, digest, have);
454: EVP_DigestFinal(&md, digest + have, NULL);
455: }
456: buffer_free(&b);
457: #ifdef DEBUG_KEX
458: fprintf(stderr, "key '%c'== ", c);
459: dump_digest("key", digest, need);
460: #endif
461: return digest;
1.1 markus 462: }
463:
1.30 markus 464: Newkeys *current_keys[MODE_MAX];
1.27 markus 465:
1.23 markus 466: #define NKEYS 6
1.26 markus 467: void
1.65 djm 468: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 469: {
1.15 markus 470: u_char *keys[NKEYS];
1.61 djm 471: u_int i, mode, ctos;
1.1 markus 472:
1.65 djm 473: for (i = 0; i < NKEYS; i++) {
474: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
475: shared_secret);
476: }
1.1 markus 477:
1.52 markus 478: debug2("kex_derive_keys");
1.1 markus 479: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 480: current_keys[mode] = kex->newkeys[mode];
481: kex->newkeys[mode] = NULL;
1.69 deraadt 482: ctos = (!kex->server && mode == MODE_OUT) ||
483: (kex->server && mode == MODE_IN);
1.30 markus 484: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
485: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
486: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 487: }
1.27 markus 488: }
489:
490: Newkeys *
491: kex_get_newkeys(int mode)
492: {
1.30 markus 493: Newkeys *ret;
494:
495: ret = current_keys[mode];
496: current_keys[mode] = NULL;
497: return ret;
1.57 djm 498: }
499:
500: void
501: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
502: u_int8_t cookie[8], u_int8_t id[16])
503: {
504: const EVP_MD *evp_md = EVP_md5();
505: EVP_MD_CTX md;
506: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
507: int len;
508:
509: EVP_DigestInit(&md, evp_md);
510:
511: len = BN_num_bytes(host_modulus);
1.61 djm 512: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 513: fatal("%s: bad host modulus (len %d)", __func__, len);
514: BN_bn2bin(host_modulus, nbuf);
515: EVP_DigestUpdate(&md, nbuf, len);
516:
517: len = BN_num_bytes(server_modulus);
1.61 djm 518: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 519: fatal("%s: bad server modulus (len %d)", __func__, len);
520: BN_bn2bin(server_modulus, nbuf);
521: EVP_DigestUpdate(&md, nbuf, len);
522:
523: EVP_DigestUpdate(&md, cookie, 8);
524:
1.58 djm 525: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 526: memcpy(id, obuf, 16);
527:
528: memset(nbuf, 0, sizeof(nbuf));
529: memset(obuf, 0, sizeof(obuf));
530: memset(&md, 0, sizeof(md));
1.1 markus 531: }
1.26 markus 532:
533: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
534: void
535: dump_digest(char *msg, u_char *digest, int len)
536: {
1.61 djm 537: u_int i;
1.26 markus 538:
539: fprintf(stderr, "%s\n", msg);
1.37 deraadt 540: for (i = 0; i< len; i++) {
1.26 markus 541: fprintf(stderr, "%02x", digest[i]);
542: if (i%32 == 31)
543: fprintf(stderr, "\n");
544: else if (i%8 == 7)
545: fprintf(stderr, " ");
546: }
547: fprintf(stderr, "\n");
548: }
549: #endif
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