Annotation of src/usr.bin/ssh/kex.c, Revision 1.70
1.1 markus 1: /*
1.36 markus 2: * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
1.1 markus 3: *
4: * Redistribution and use in source and binary forms, with or without
5: * modification, are permitted provided that the following conditions
6: * are met:
7: * 1. Redistributions of source code must retain the above copyright
8: * notice, this list of conditions and the following disclaimer.
9: * 2. Redistributions in binary form must reproduce the above copyright
10: * notice, this list of conditions and the following disclaimer in the
11: * documentation and/or other materials provided with the distribution.
12: *
13: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23: */
24:
25: #include "includes.h"
1.18 markus 26:
27: #include <openssl/crypto.h>
1.1 markus 28:
29: #include "ssh2.h"
30: #include "xmalloc.h"
31: #include "buffer.h"
32: #include "bufaux.h"
1.7 markus 33: #include "packet.h"
1.1 markus 34: #include "compat.h"
1.18 markus 35: #include "cipher.h"
1.1 markus 36: #include "kex.h"
1.13 markus 37: #include "key.h"
1.18 markus 38: #include "log.h"
1.21 markus 39: #include "mac.h"
1.23 markus 40: #include "match.h"
1.26 markus 41: #include "dispatch.h"
1.48 provos 42: #include "monitor.h"
1.1 markus 43:
1.7 markus 44: #define KEX_COOKIE_LEN 16
1.48 provos 45:
1.66 djm 46: extern const EVP_MD *evp_ssh_sha256(void);
47:
1.35 itojun 48: /* prototype */
49: static void kex_kexinit_finish(Kex *);
50: static void kex_choose_conf(Kex *);
1.26 markus 51:
52: /* put algorithm proposal into buffer */
1.35 itojun 53: static void
1.26 markus 54: kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
1.1 markus 55: {
1.61 djm 56: u_int i;
1.26 markus 57:
58: buffer_clear(b);
1.49 markus 59: /*
60: * add a dummy cookie, the cookie will be overwritten by
61: * kex_send_kexinit(), each time a kexinit is set
62: */
63: for (i = 0; i < KEX_COOKIE_LEN; i++)
64: buffer_put_char(b, 0);
1.1 markus 65: for (i = 0; i < PROPOSAL_MAX; i++)
1.26 markus 66: buffer_put_cstring(b, proposal[i]);
67: buffer_put_char(b, 0); /* first_kex_packet_follows */
68: buffer_put_int(b, 0); /* uint32 reserved */
1.1 markus 69: }
70:
1.26 markus 71: /* parse buffer and return algorithm proposal */
1.35 itojun 72: static char **
1.53 markus 73: kex_buf2prop(Buffer *raw, int *first_kex_follows)
1.7 markus 74: {
1.26 markus 75: Buffer b;
1.7 markus 76: int i;
1.26 markus 77: char **proposal;
1.7 markus 78:
1.70 ! djm 79: proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
1.7 markus 80:
1.26 markus 81: buffer_init(&b);
82: buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
1.7 markus 83: /* skip cookie */
84: for (i = 0; i < KEX_COOKIE_LEN; i++)
1.26 markus 85: buffer_get_char(&b);
1.7 markus 86: /* extract kex init proposal strings */
87: for (i = 0; i < PROPOSAL_MAX; i++) {
1.26 markus 88: proposal[i] = buffer_get_string(&b,NULL);
89: debug2("kex_parse_kexinit: %s", proposal[i]);
1.7 markus 90: }
1.26 markus 91: /* first kex follows / reserved */
92: i = buffer_get_char(&b);
1.53 markus 93: if (first_kex_follows != NULL)
94: *first_kex_follows = i;
1.26 markus 95: debug2("kex_parse_kexinit: first_kex_follows %d ", i);
96: i = buffer_get_int(&b);
97: debug2("kex_parse_kexinit: reserved %d ", i);
98: buffer_free(&b);
99: return proposal;
1.1 markus 100: }
101:
1.35 itojun 102: static void
1.26 markus 103: kex_prop_free(char **proposal)
1.1 markus 104: {
1.61 djm 105: u_int i;
1.26 markus 106:
107: for (i = 0; i < PROPOSAL_MAX; i++)
108: xfree(proposal[i]);
109: xfree(proposal);
1.1 markus 110: }
111:
1.35 itojun 112: static void
1.41 markus 113: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 114: {
1.41 markus 115: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 116: }
1.1 markus 117:
1.35 itojun 118: static void
1.44 markus 119: kex_reset_dispatch(void)
1.29 markus 120: {
1.42 markus 121: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
122: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 123: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 124: }
125:
126: void
1.28 markus 127: kex_finish(Kex *kex)
1.26 markus 128: {
1.44 markus 129: kex_reset_dispatch();
1.28 markus 130:
1.26 markus 131: packet_start(SSH2_MSG_NEWKEYS);
132: packet_send();
133: /* packet_write_wait(); */
134: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 135:
1.52 markus 136: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 137: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 138: packet_check_eom();
1.26 markus 139: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 140:
1.30 markus 141: kex->done = 1;
1.26 markus 142: buffer_clear(&kex->peer);
1.27 markus 143: /* buffer_clear(&kex->my); */
1.26 markus 144: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 145: xfree(kex->name);
146: kex->name = NULL;
1.26 markus 147: }
1.1 markus 148:
1.26 markus 149: void
150: kex_send_kexinit(Kex *kex)
151: {
1.60 avsm 152: u_int32_t rnd = 0;
1.49 markus 153: u_char *cookie;
1.61 djm 154: u_int i;
1.49 markus 155:
1.29 markus 156: if (kex == NULL) {
157: error("kex_send_kexinit: no kex, cannot rekey");
158: return;
159: }
1.28 markus 160: if (kex->flags & KEX_INIT_SENT) {
161: debug("KEX_INIT_SENT");
162: return;
163: }
1.30 markus 164: kex->done = 0;
1.49 markus 165:
166: /* generate a random cookie */
167: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
168: fatal("kex_send_kexinit: kex proposal too short");
169: cookie = buffer_ptr(&kex->my);
170: for (i = 0; i < KEX_COOKIE_LEN; i++) {
171: if (i % 4 == 0)
1.60 avsm 172: rnd = arc4random();
173: cookie[i] = rnd;
174: rnd >>= 8;
1.49 markus 175: }
1.26 markus 176: packet_start(SSH2_MSG_KEXINIT);
177: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
178: packet_send();
179: debug("SSH2_MSG_KEXINIT sent");
180: kex->flags |= KEX_INIT_SENT;
1.1 markus 181: }
182:
1.26 markus 183: void
1.41 markus 184: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 185: {
1.26 markus 186: char *ptr;
1.61 djm 187: u_int i, dlen;
1.26 markus 188: Kex *kex = (Kex *)ctxt;
1.11 provos 189:
1.26 markus 190: debug("SSH2_MSG_KEXINIT received");
1.29 markus 191: if (kex == NULL)
192: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 193:
1.26 markus 194: ptr = packet_get_raw(&dlen);
195: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 196:
197: /* discard packet */
198: for (i = 0; i < KEX_COOKIE_LEN; i++)
199: packet_get_char();
200: for (i = 0; i < PROPOSAL_MAX; i++)
201: xfree(packet_get_string(NULL));
1.51 markus 202: (void) packet_get_char();
203: (void) packet_get_int();
1.39 markus 204: packet_check_eom();
1.19 stevesk 205:
1.26 markus 206: kex_kexinit_finish(kex);
207: }
1.11 provos 208:
1.26 markus 209: Kex *
1.28 markus 210: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 211: {
212: Kex *kex;
1.11 provos 213:
1.70 ! djm 214: kex = xcalloc(1, sizeof(*kex));
1.26 markus 215: buffer_init(&kex->peer);
216: buffer_init(&kex->my);
217: kex_prop2buf(&kex->my, proposal);
1.30 markus 218: kex->done = 0;
1.26 markus 219:
220: kex_send_kexinit(kex); /* we start */
1.44 markus 221: kex_reset_dispatch();
1.26 markus 222:
223: return kex;
1.11 provos 224: }
225:
1.35 itojun 226: static void
1.26 markus 227: kex_kexinit_finish(Kex *kex)
1.1 markus 228: {
1.26 markus 229: if (!(kex->flags & KEX_INIT_SENT))
230: kex_send_kexinit(kex);
1.1 markus 231:
1.26 markus 232: kex_choose_conf(kex);
1.1 markus 233:
1.54 markus 234: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
235: kex->kex[kex->kex_type] != NULL) {
236: (kex->kex[kex->kex_type])(kex);
237: } else {
1.26 markus 238: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 239: }
240: }
241:
1.35 itojun 242: static void
1.1 markus 243: choose_enc(Enc *enc, char *client, char *server)
244: {
1.23 markus 245: char *name = match_list(client, server, NULL);
1.1 markus 246: if (name == NULL)
247: fatal("no matching cipher found: client %s server %s", client, server);
1.45 markus 248: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 249: fatal("matching cipher is not supported: %s", name);
1.1 markus 250: enc->name = name;
251: enc->enabled = 0;
252: enc->iv = NULL;
253: enc->key = NULL;
1.45 markus 254: enc->key_len = cipher_keylen(enc->cipher);
255: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 256: }
1.69 deraadt 257:
1.35 itojun 258: static void
1.1 markus 259: choose_mac(Mac *mac, char *client, char *server)
260: {
1.23 markus 261: char *name = match_list(client, server, NULL);
1.1 markus 262: if (name == NULL)
263: fatal("no matching mac found: client %s server %s", client, server);
1.21 markus 264: if (mac_init(mac, name) < 0)
1.1 markus 265: fatal("unsupported mac %s", name);
1.21 markus 266: /* truncate the key */
267: if (datafellows & SSH_BUG_HMAC)
268: mac->key_len = 16;
1.1 markus 269: mac->name = name;
270: mac->key = NULL;
271: mac->enabled = 0;
272: }
1.69 deraadt 273:
1.35 itojun 274: static void
1.1 markus 275: choose_comp(Comp *comp, char *client, char *server)
276: {
1.23 markus 277: char *name = match_list(client, server, NULL);
1.1 markus 278: if (name == NULL)
279: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 280: if (strcmp(name, "zlib@openssh.com") == 0) {
281: comp->type = COMP_DELAYED;
282: } else if (strcmp(name, "zlib") == 0) {
283: comp->type = COMP_ZLIB;
1.1 markus 284: } else if (strcmp(name, "none") == 0) {
1.64 markus 285: comp->type = COMP_NONE;
1.1 markus 286: } else {
287: fatal("unsupported comp %s", name);
288: }
289: comp->name = name;
290: }
1.69 deraadt 291:
1.35 itojun 292: static void
1.1 markus 293: choose_kex(Kex *k, char *client, char *server)
294: {
1.23 markus 295: k->name = match_list(client, server, NULL);
1.1 markus 296: if (k->name == NULL)
297: fatal("no kex alg");
1.11 provos 298: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 299: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 300: k->evp_md = EVP_sha1();
1.59 djm 301: } else if (strcmp(k->name, KEX_DH14) == 0) {
302: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 303: k->evp_md = EVP_sha1();
304: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 305: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 306: k->evp_md = EVP_sha1();
1.66 djm 307: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
308: k->kex_type = KEX_DH_GEX_SHA256;
309: k->evp_md = evp_ssh_sha256();
1.11 provos 310: } else
1.1 markus 311: fatal("bad kex alg %s", k->name);
312: }
1.65 djm 313:
1.35 itojun 314: static void
1.1 markus 315: choose_hostkeyalg(Kex *k, char *client, char *server)
316: {
1.23 markus 317: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 318: if (hostkeyalg == NULL)
1.1 markus 319: fatal("no hostkey alg");
1.13 markus 320: k->hostkey_type = key_type_from_name(hostkeyalg);
321: if (k->hostkey_type == KEY_UNSPEC)
322: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 323: xfree(hostkeyalg);
1.1 markus 324: }
325:
1.56 djm 326: static int
1.53 markus 327: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
328: {
329: static int check[] = {
330: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
331: };
332: int *idx;
333: char *p;
334:
335: for (idx = &check[0]; *idx != -1; idx++) {
336: if ((p = strchr(my[*idx], ',')) != NULL)
337: *p = '\0';
338: if ((p = strchr(peer[*idx], ',')) != NULL)
339: *p = '\0';
340: if (strcmp(my[*idx], peer[*idx]) != 0) {
341: debug2("proposal mismatch: my %s peer %s",
342: my[*idx], peer[*idx]);
343: return (0);
344: }
345: }
346: debug2("proposals match");
347: return (1);
348: }
349:
1.35 itojun 350: static void
1.27 markus 351: kex_choose_conf(Kex *kex)
1.1 markus 352: {
1.27 markus 353: Newkeys *newkeys;
1.26 markus 354: char **my, **peer;
355: char **cprop, **sprop;
1.27 markus 356: int nenc, nmac, ncomp;
1.61 djm 357: u_int mode, ctos, need;
1.53 markus 358: int first_kex_follows, type;
1.1 markus 359:
1.53 markus 360: my = kex_buf2prop(&kex->my, NULL);
361: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 362:
1.27 markus 363: if (kex->server) {
1.26 markus 364: cprop=peer;
365: sprop=my;
366: } else {
367: cprop=my;
368: sprop=peer;
369: }
1.1 markus 370:
1.30 markus 371: /* Algorithm Negotiation */
1.1 markus 372: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 ! djm 373: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 374: kex->newkeys[mode] = newkeys;
1.27 markus 375: ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
1.1 markus 376: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
377: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
378: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 379: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
380: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
381: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 382: debug("kex: %s %s %s %s",
1.1 markus 383: ctos ? "client->server" : "server->client",
1.27 markus 384: newkeys->enc.name,
385: newkeys->mac.name,
386: newkeys->comp.name);
1.1 markus 387: }
1.27 markus 388: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
389: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 390: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
391: need = 0;
392: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 393: newkeys = kex->newkeys[mode];
1.45 markus 394: if (need < newkeys->enc.key_len)
395: need = newkeys->enc.key_len;
396: if (need < newkeys->enc.block_size)
397: need = newkeys->enc.block_size;
1.27 markus 398: if (need < newkeys->mac.key_len)
399: need = newkeys->mac.key_len;
1.1 markus 400: }
1.7 markus 401: /* XXX need runden? */
1.27 markus 402: kex->we_need = need;
1.53 markus 403:
404: /* ignore the next message if the proposals do not match */
1.56 djm 405: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 406: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 407: type = packet_read();
408: debug2("skipping next packet (type %u)", type);
409: }
1.26 markus 410:
411: kex_prop_free(my);
412: kex_prop_free(peer);
413: }
414:
1.35 itojun 415: static u_char *
1.65 djm 416: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
417: BIGNUM *shared_secret)
1.26 markus 418: {
419: Buffer b;
420: EVP_MD_CTX md;
421: char c = id;
1.61 djm 422: u_int have;
1.65 djm 423: int mdsz;
1.61 djm 424: u_char *digest;
1.62 djm 425:
1.65 djm 426: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
427: fatal("bad kex md size %d", mdsz);
1.68 deraadt 428: digest = xmalloc(roundup(need, mdsz));
1.26 markus 429:
430: buffer_init(&b);
431: buffer_put_bignum2(&b, shared_secret);
432:
1.30 markus 433: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 434: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 435: if (!(datafellows & SSH_BUG_DERIVEKEY))
436: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 437: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 438: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 439: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 440: EVP_DigestFinal(&md, digest, NULL);
441:
1.30 markus 442: /*
443: * expand key:
444: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
445: * Key = K1 || K2 || ... || Kn
446: */
1.26 markus 447: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 448: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 449: if (!(datafellows & SSH_BUG_DERIVEKEY))
450: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 451: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 452: EVP_DigestUpdate(&md, digest, have);
453: EVP_DigestFinal(&md, digest + have, NULL);
454: }
455: buffer_free(&b);
456: #ifdef DEBUG_KEX
457: fprintf(stderr, "key '%c'== ", c);
458: dump_digest("key", digest, need);
459: #endif
460: return digest;
1.1 markus 461: }
462:
1.30 markus 463: Newkeys *current_keys[MODE_MAX];
1.27 markus 464:
1.23 markus 465: #define NKEYS 6
1.26 markus 466: void
1.65 djm 467: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 468: {
1.15 markus 469: u_char *keys[NKEYS];
1.61 djm 470: u_int i, mode, ctos;
1.1 markus 471:
1.65 djm 472: for (i = 0; i < NKEYS; i++) {
473: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
474: shared_secret);
475: }
1.1 markus 476:
1.52 markus 477: debug2("kex_derive_keys");
1.1 markus 478: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 479: current_keys[mode] = kex->newkeys[mode];
480: kex->newkeys[mode] = NULL;
1.69 deraadt 481: ctos = (!kex->server && mode == MODE_OUT) ||
482: (kex->server && mode == MODE_IN);
1.30 markus 483: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
484: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
485: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 486: }
1.27 markus 487: }
488:
489: Newkeys *
490: kex_get_newkeys(int mode)
491: {
1.30 markus 492: Newkeys *ret;
493:
494: ret = current_keys[mode];
495: current_keys[mode] = NULL;
496: return ret;
1.57 djm 497: }
498:
499: void
500: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
501: u_int8_t cookie[8], u_int8_t id[16])
502: {
503: const EVP_MD *evp_md = EVP_md5();
504: EVP_MD_CTX md;
505: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
506: int len;
507:
508: EVP_DigestInit(&md, evp_md);
509:
510: len = BN_num_bytes(host_modulus);
1.61 djm 511: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 512: fatal("%s: bad host modulus (len %d)", __func__, len);
513: BN_bn2bin(host_modulus, nbuf);
514: EVP_DigestUpdate(&md, nbuf, len);
515:
516: len = BN_num_bytes(server_modulus);
1.61 djm 517: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 518: fatal("%s: bad server modulus (len %d)", __func__, len);
519: BN_bn2bin(server_modulus, nbuf);
520: EVP_DigestUpdate(&md, nbuf, len);
521:
522: EVP_DigestUpdate(&md, cookie, 8);
523:
1.58 djm 524: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 525: memcpy(id, obuf, 16);
526:
527: memset(nbuf, 0, sizeof(nbuf));
528: memset(obuf, 0, sizeof(obuf));
529: memset(&md, 0, sizeof(md));
1.1 markus 530: }
1.26 markus 531:
532: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)
533: void
534: dump_digest(char *msg, u_char *digest, int len)
535: {
1.61 djm 536: u_int i;
1.26 markus 537:
538: fprintf(stderr, "%s\n", msg);
1.37 deraadt 539: for (i = 0; i< len; i++) {
1.26 markus 540: fprintf(stderr, "%02x", digest[i]);
541: if (i%32 == 31)
542: fprintf(stderr, "\n");
543: else if (i%8 == 7)
544: fprintf(stderr, " ");
545: }
546: fprintf(stderr, "\n");
547: }
548: #endif
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