Annotation of src/usr.bin/ssh/kex.c, Revision 1.86
1.86 ! djm 1: /* $OpenBSD: kex.c,v 1.85 2010/09/09 10:45:45 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"
1.82 andreas 48: #include "roaming.h"
1.48 provos 49:
1.35 itojun 50: /* prototype */
51: static void kex_kexinit_finish(Kex *);
52: static void kex_choose_conf(Kex *);
1.86 ! djm 53:
! 54: /* Validate KEX method name list */
! 55: int
! 56: kex_names_valid(const char *names)
! 57: {
! 58: char *s, *cp, *p;
! 59:
! 60: if (names == NULL || strcmp(names, "") == 0)
! 61: return 0;
! 62: s = cp = xstrdup(names);
! 63: for ((p = strsep(&cp, ",")); p && *p != '\0';
! 64: (p = strsep(&cp, ","))) {
! 65: if (strcmp(p, KEX_DHGEX_SHA256) != 0 &&
! 66: strcmp(p, KEX_DHGEX_SHA1) != 0 &&
! 67: strcmp(p, KEX_DH14) != 0 &&
! 68: strcmp(p, KEX_DH1) != 0 &&
! 69: (strncmp(p, KEX_ECDH_SHA2_STEM,
! 70: sizeof(KEX_ECDH_SHA2_STEM) - 1) != 0 ||
! 71: kex_ecdh_name_to_nid(p) == -1)) {
! 72: error("Unsupported KEX algorithm \"%.100s\"", p);
! 73: xfree(s);
! 74: return 0;
! 75: }
! 76: }
! 77: debug3("kex names ok: [%s]", names);
! 78: xfree(s);
! 79: return 1;
! 80: }
1.26 markus 81:
82: /* put algorithm proposal into buffer */
1.35 itojun 83: static void
1.26 markus 84: kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX])
1.1 markus 85: {
1.61 djm 86: u_int i;
1.26 markus 87:
88: buffer_clear(b);
1.49 markus 89: /*
90: * add a dummy cookie, the cookie will be overwritten by
91: * kex_send_kexinit(), each time a kexinit is set
92: */
93: for (i = 0; i < KEX_COOKIE_LEN; i++)
94: buffer_put_char(b, 0);
1.1 markus 95: for (i = 0; i < PROPOSAL_MAX; i++)
1.26 markus 96: buffer_put_cstring(b, proposal[i]);
97: buffer_put_char(b, 0); /* first_kex_packet_follows */
98: buffer_put_int(b, 0); /* uint32 reserved */
1.1 markus 99: }
100:
1.26 markus 101: /* parse buffer and return algorithm proposal */
1.35 itojun 102: static char **
1.53 markus 103: kex_buf2prop(Buffer *raw, int *first_kex_follows)
1.7 markus 104: {
1.26 markus 105: Buffer b;
1.78 djm 106: u_int i;
1.26 markus 107: char **proposal;
1.7 markus 108:
1.70 djm 109: proposal = xcalloc(PROPOSAL_MAX, sizeof(char *));
1.7 markus 110:
1.26 markus 111: buffer_init(&b);
112: buffer_append(&b, buffer_ptr(raw), buffer_len(raw));
1.7 markus 113: /* skip cookie */
114: for (i = 0; i < KEX_COOKIE_LEN; i++)
1.26 markus 115: buffer_get_char(&b);
1.7 markus 116: /* extract kex init proposal strings */
117: for (i = 0; i < PROPOSAL_MAX; i++) {
1.83 djm 118: proposal[i] = buffer_get_cstring(&b,NULL);
1.26 markus 119: debug2("kex_parse_kexinit: %s", proposal[i]);
1.7 markus 120: }
1.26 markus 121: /* first kex follows / reserved */
122: i = buffer_get_char(&b);
1.53 markus 123: if (first_kex_follows != NULL)
124: *first_kex_follows = i;
1.26 markus 125: debug2("kex_parse_kexinit: first_kex_follows %d ", i);
126: i = buffer_get_int(&b);
1.78 djm 127: debug2("kex_parse_kexinit: reserved %u ", i);
1.26 markus 128: buffer_free(&b);
129: return proposal;
1.1 markus 130: }
131:
1.35 itojun 132: static void
1.26 markus 133: kex_prop_free(char **proposal)
1.1 markus 134: {
1.61 djm 135: u_int i;
1.26 markus 136:
137: for (i = 0; i < PROPOSAL_MAX; i++)
138: xfree(proposal[i]);
139: xfree(proposal);
1.1 markus 140: }
141:
1.78 djm 142: /* ARGSUSED */
1.35 itojun 143: static void
1.41 markus 144: kex_protocol_error(int type, u_int32_t seq, void *ctxt)
1.1 markus 145: {
1.41 markus 146: error("Hm, kex protocol error: type %d seq %u", type, seq);
1.26 markus 147: }
1.1 markus 148:
1.35 itojun 149: static void
1.44 markus 150: kex_reset_dispatch(void)
1.29 markus 151: {
1.42 markus 152: dispatch_range(SSH2_MSG_TRANSPORT_MIN,
153: SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
1.44 markus 154: dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit);
1.29 markus 155: }
156:
157: void
1.28 markus 158: kex_finish(Kex *kex)
1.26 markus 159: {
1.44 markus 160: kex_reset_dispatch();
1.28 markus 161:
1.26 markus 162: packet_start(SSH2_MSG_NEWKEYS);
163: packet_send();
164: /* packet_write_wait(); */
165: debug("SSH2_MSG_NEWKEYS sent");
1.19 stevesk 166:
1.52 markus 167: debug("expecting SSH2_MSG_NEWKEYS");
1.40 markus 168: packet_read_expect(SSH2_MSG_NEWKEYS);
1.46 markus 169: packet_check_eom();
1.26 markus 170: debug("SSH2_MSG_NEWKEYS received");
1.32 markus 171:
1.30 markus 172: kex->done = 1;
1.26 markus 173: buffer_clear(&kex->peer);
1.27 markus 174: /* buffer_clear(&kex->my); */
1.26 markus 175: kex->flags &= ~KEX_INIT_SENT;
1.32 markus 176: xfree(kex->name);
177: kex->name = NULL;
1.26 markus 178: }
1.1 markus 179:
1.26 markus 180: void
181: kex_send_kexinit(Kex *kex)
182: {
1.60 avsm 183: u_int32_t rnd = 0;
1.49 markus 184: u_char *cookie;
1.61 djm 185: u_int i;
1.49 markus 186:
1.29 markus 187: if (kex == NULL) {
188: error("kex_send_kexinit: no kex, cannot rekey");
189: return;
190: }
1.28 markus 191: if (kex->flags & KEX_INIT_SENT) {
192: debug("KEX_INIT_SENT");
193: return;
194: }
1.30 markus 195: kex->done = 0;
1.49 markus 196:
197: /* generate a random cookie */
198: if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
199: fatal("kex_send_kexinit: kex proposal too short");
200: cookie = buffer_ptr(&kex->my);
201: for (i = 0; i < KEX_COOKIE_LEN; i++) {
202: if (i % 4 == 0)
1.60 avsm 203: rnd = arc4random();
204: cookie[i] = rnd;
205: rnd >>= 8;
1.49 markus 206: }
1.26 markus 207: packet_start(SSH2_MSG_KEXINIT);
208: packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
209: packet_send();
210: debug("SSH2_MSG_KEXINIT sent");
211: kex->flags |= KEX_INIT_SENT;
1.1 markus 212: }
213:
1.78 djm 214: /* ARGSUSED */
1.26 markus 215: void
1.41 markus 216: kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
1.11 provos 217: {
1.26 markus 218: char *ptr;
1.61 djm 219: u_int i, dlen;
1.26 markus 220: Kex *kex = (Kex *)ctxt;
1.11 provos 221:
1.26 markus 222: debug("SSH2_MSG_KEXINIT received");
1.29 markus 223: if (kex == NULL)
224: fatal("kex_input_kexinit: no kex, cannot rekey");
1.11 provos 225:
1.26 markus 226: ptr = packet_get_raw(&dlen);
227: buffer_append(&kex->peer, ptr, dlen);
1.31 markus 228:
229: /* discard packet */
230: for (i = 0; i < KEX_COOKIE_LEN; i++)
231: packet_get_char();
232: for (i = 0; i < PROPOSAL_MAX; i++)
233: xfree(packet_get_string(NULL));
1.51 markus 234: (void) packet_get_char();
235: (void) packet_get_int();
1.39 markus 236: packet_check_eom();
1.19 stevesk 237:
1.26 markus 238: kex_kexinit_finish(kex);
239: }
1.11 provos 240:
1.26 markus 241: Kex *
1.28 markus 242: kex_setup(char *proposal[PROPOSAL_MAX])
1.26 markus 243: {
244: Kex *kex;
1.11 provos 245:
1.70 djm 246: kex = xcalloc(1, sizeof(*kex));
1.26 markus 247: buffer_init(&kex->peer);
248: buffer_init(&kex->my);
249: kex_prop2buf(&kex->my, proposal);
1.30 markus 250: kex->done = 0;
1.26 markus 251:
252: kex_send_kexinit(kex); /* we start */
1.44 markus 253: kex_reset_dispatch();
1.26 markus 254:
255: return kex;
1.11 provos 256: }
257:
1.35 itojun 258: static void
1.26 markus 259: kex_kexinit_finish(Kex *kex)
1.1 markus 260: {
1.26 markus 261: if (!(kex->flags & KEX_INIT_SENT))
262: kex_send_kexinit(kex);
1.1 markus 263:
1.26 markus 264: kex_choose_conf(kex);
1.1 markus 265:
1.54 markus 266: if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
267: kex->kex[kex->kex_type] != NULL) {
268: (kex->kex[kex->kex_type])(kex);
269: } else {
1.26 markus 270: fatal("Unsupported key exchange %d", kex->kex_type);
1.1 markus 271: }
272: }
273:
1.35 itojun 274: static void
1.1 markus 275: choose_enc(Enc *enc, char *client, char *server)
276: {
1.23 markus 277: char *name = match_list(client, server, NULL);
1.1 markus 278: if (name == NULL)
1.78 djm 279: fatal("no matching cipher found: client %s server %s",
280: client, server);
1.45 markus 281: if ((enc->cipher = cipher_by_name(name)) == NULL)
1.12 markus 282: fatal("matching cipher is not supported: %s", name);
1.1 markus 283: enc->name = name;
284: enc->enabled = 0;
285: enc->iv = NULL;
286: enc->key = NULL;
1.45 markus 287: enc->key_len = cipher_keylen(enc->cipher);
288: enc->block_size = cipher_blocksize(enc->cipher);
1.1 markus 289: }
1.69 deraadt 290:
1.35 itojun 291: static void
1.1 markus 292: choose_mac(Mac *mac, char *client, char *server)
293: {
1.23 markus 294: char *name = match_list(client, server, NULL);
1.1 markus 295: if (name == NULL)
1.78 djm 296: fatal("no matching mac found: client %s server %s",
297: client, server);
1.79 djm 298: if (mac_setup(mac, name) < 0)
1.1 markus 299: fatal("unsupported mac %s", name);
1.21 markus 300: /* truncate the key */
301: if (datafellows & SSH_BUG_HMAC)
302: mac->key_len = 16;
1.1 markus 303: mac->name = name;
304: mac->key = NULL;
305: mac->enabled = 0;
306: }
1.69 deraadt 307:
1.35 itojun 308: static void
1.1 markus 309: choose_comp(Comp *comp, char *client, char *server)
310: {
1.23 markus 311: char *name = match_list(client, server, NULL);
1.1 markus 312: if (name == NULL)
313: fatal("no matching comp found: client %s server %s", client, server);
1.64 markus 314: if (strcmp(name, "zlib@openssh.com") == 0) {
315: comp->type = COMP_DELAYED;
316: } else if (strcmp(name, "zlib") == 0) {
317: comp->type = COMP_ZLIB;
1.1 markus 318: } else if (strcmp(name, "none") == 0) {
1.64 markus 319: comp->type = COMP_NONE;
1.1 markus 320: } else {
321: fatal("unsupported comp %s", name);
322: }
323: comp->name = name;
324: }
1.69 deraadt 325:
1.35 itojun 326: static void
1.1 markus 327: choose_kex(Kex *k, char *client, char *server)
328: {
1.23 markus 329: k->name = match_list(client, server, NULL);
1.1 markus 330: if (k->name == NULL)
1.78 djm 331: fatal("Unable to negotiate a key exchange method");
1.11 provos 332: if (strcmp(k->name, KEX_DH1) == 0) {
1.54 markus 333: k->kex_type = KEX_DH_GRP1_SHA1;
1.65 djm 334: k->evp_md = EVP_sha1();
1.59 djm 335: } else if (strcmp(k->name, KEX_DH14) == 0) {
336: k->kex_type = KEX_DH_GRP14_SHA1;
1.65 djm 337: k->evp_md = EVP_sha1();
338: } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) {
1.54 markus 339: k->kex_type = KEX_DH_GEX_SHA1;
1.65 djm 340: k->evp_md = EVP_sha1();
1.66 djm 341: } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) {
342: k->kex_type = KEX_DH_GEX_SHA256;
1.80 djm 343: k->evp_md = EVP_sha256();
1.85 djm 344: } else if (strncmp(k->name, KEX_ECDH_SHA2_STEM,
345: sizeof(KEX_ECDH_SHA2_STEM) - 1) == 0) {
1.84 djm 346: k->kex_type = KEX_ECDH_SHA2;
1.85 djm 347: k->evp_md = kex_ecdh_name_to_evpmd(k->name);
1.11 provos 348: } else
1.1 markus 349: fatal("bad kex alg %s", k->name);
350: }
1.65 djm 351:
1.35 itojun 352: static void
1.1 markus 353: choose_hostkeyalg(Kex *k, char *client, char *server)
354: {
1.23 markus 355: char *hostkeyalg = match_list(client, server, NULL);
1.13 markus 356: if (hostkeyalg == NULL)
1.1 markus 357: fatal("no hostkey alg");
1.13 markus 358: k->hostkey_type = key_type_from_name(hostkeyalg);
359: if (k->hostkey_type == KEY_UNSPEC)
360: fatal("bad hostkey alg '%s'", hostkeyalg);
1.17 markus 361: xfree(hostkeyalg);
1.1 markus 362: }
363:
1.56 djm 364: static int
1.53 markus 365: proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
366: {
367: static int check[] = {
368: PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1
369: };
370: int *idx;
371: char *p;
372:
373: for (idx = &check[0]; *idx != -1; idx++) {
374: if ((p = strchr(my[*idx], ',')) != NULL)
375: *p = '\0';
376: if ((p = strchr(peer[*idx], ',')) != NULL)
377: *p = '\0';
378: if (strcmp(my[*idx], peer[*idx]) != 0) {
379: debug2("proposal mismatch: my %s peer %s",
380: my[*idx], peer[*idx]);
381: return (0);
382: }
383: }
384: debug2("proposals match");
385: return (1);
386: }
387:
1.35 itojun 388: static void
1.27 markus 389: kex_choose_conf(Kex *kex)
1.1 markus 390: {
1.27 markus 391: Newkeys *newkeys;
1.26 markus 392: char **my, **peer;
393: char **cprop, **sprop;
1.27 markus 394: int nenc, nmac, ncomp;
1.61 djm 395: u_int mode, ctos, need;
1.53 markus 396: int first_kex_follows, type;
1.1 markus 397:
1.53 markus 398: my = kex_buf2prop(&kex->my, NULL);
399: peer = kex_buf2prop(&kex->peer, &first_kex_follows);
1.26 markus 400:
1.27 markus 401: if (kex->server) {
1.26 markus 402: cprop=peer;
403: sprop=my;
404: } else {
405: cprop=my;
406: sprop=peer;
1.82 andreas 407: }
408:
409: /* Check whether server offers roaming */
410: if (!kex->server) {
411: char *roaming;
412: roaming = match_list(KEX_RESUME, peer[PROPOSAL_KEX_ALGS], NULL);
413: if (roaming) {
414: kex->roaming = 1;
415: xfree(roaming);
416: }
1.26 markus 417: }
1.1 markus 418:
1.30 markus 419: /* Algorithm Negotiation */
1.1 markus 420: for (mode = 0; mode < MODE_MAX; mode++) {
1.70 djm 421: newkeys = xcalloc(1, sizeof(*newkeys));
1.30 markus 422: kex->newkeys[mode] = newkeys;
1.78 djm 423: ctos = (!kex->server && mode == MODE_OUT) ||
424: (kex->server && mode == MODE_IN);
1.1 markus 425: nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
426: nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
427: ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
1.27 markus 428: choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]);
429: choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]);
430: choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]);
1.2 markus 431: debug("kex: %s %s %s %s",
1.1 markus 432: ctos ? "client->server" : "server->client",
1.27 markus 433: newkeys->enc.name,
434: newkeys->mac.name,
435: newkeys->comp.name);
1.1 markus 436: }
1.27 markus 437: choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]);
438: choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
1.1 markus 439: sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
440: need = 0;
441: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 442: newkeys = kex->newkeys[mode];
1.45 markus 443: if (need < newkeys->enc.key_len)
444: need = newkeys->enc.key_len;
445: if (need < newkeys->enc.block_size)
446: need = newkeys->enc.block_size;
1.27 markus 447: if (need < newkeys->mac.key_len)
448: need = newkeys->mac.key_len;
1.1 markus 449: }
1.7 markus 450: /* XXX need runden? */
1.27 markus 451: kex->we_need = need;
1.53 markus 452:
453: /* ignore the next message if the proposals do not match */
1.56 djm 454: if (first_kex_follows && !proposals_match(my, peer) &&
1.63 djm 455: !(datafellows & SSH_BUG_FIRSTKEX)) {
1.53 markus 456: type = packet_read();
457: debug2("skipping next packet (type %u)", type);
458: }
1.26 markus 459:
460: kex_prop_free(my);
461: kex_prop_free(peer);
462: }
463:
1.35 itojun 464: static u_char *
1.65 djm 465: derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen,
466: BIGNUM *shared_secret)
1.26 markus 467: {
468: Buffer b;
469: EVP_MD_CTX md;
470: char c = id;
1.61 djm 471: u_int have;
1.65 djm 472: int mdsz;
1.61 djm 473: u_char *digest;
1.62 djm 474:
1.65 djm 475: if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0)
476: fatal("bad kex md size %d", mdsz);
1.68 deraadt 477: digest = xmalloc(roundup(need, mdsz));
1.26 markus 478:
479: buffer_init(&b);
480: buffer_put_bignum2(&b, shared_secret);
481:
1.30 markus 482: /* K1 = HASH(K || H || "A" || session_id) */
1.65 djm 483: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 484: if (!(datafellows & SSH_BUG_DERIVEKEY))
485: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 486: EVP_DigestUpdate(&md, hash, hashlen);
1.30 markus 487: EVP_DigestUpdate(&md, &c, 1);
1.27 markus 488: EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
1.26 markus 489: EVP_DigestFinal(&md, digest, NULL);
490:
1.30 markus 491: /*
492: * expand key:
493: * Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
494: * Key = K1 || K2 || ... || Kn
495: */
1.26 markus 496: for (have = mdsz; need > have; have += mdsz) {
1.65 djm 497: EVP_DigestInit(&md, kex->evp_md);
1.34 markus 498: if (!(datafellows & SSH_BUG_DERIVEKEY))
499: EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
1.65 djm 500: EVP_DigestUpdate(&md, hash, hashlen);
1.26 markus 501: EVP_DigestUpdate(&md, digest, have);
502: EVP_DigestFinal(&md, digest + have, NULL);
503: }
504: buffer_free(&b);
505: #ifdef DEBUG_KEX
506: fprintf(stderr, "key '%c'== ", c);
507: dump_digest("key", digest, need);
508: #endif
509: return digest;
1.1 markus 510: }
511:
1.30 markus 512: Newkeys *current_keys[MODE_MAX];
1.27 markus 513:
1.23 markus 514: #define NKEYS 6
1.26 markus 515: void
1.65 djm 516: kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret)
1.1 markus 517: {
1.15 markus 518: u_char *keys[NKEYS];
1.61 djm 519: u_int i, mode, ctos;
1.1 markus 520:
1.65 djm 521: for (i = 0; i < NKEYS; i++) {
522: keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen,
523: shared_secret);
524: }
1.1 markus 525:
1.52 markus 526: debug2("kex_derive_keys");
1.1 markus 527: for (mode = 0; mode < MODE_MAX; mode++) {
1.30 markus 528: current_keys[mode] = kex->newkeys[mode];
529: kex->newkeys[mode] = NULL;
1.69 deraadt 530: ctos = (!kex->server && mode == MODE_OUT) ||
531: (kex->server && mode == MODE_IN);
1.30 markus 532: current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
533: current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
534: current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
1.1 markus 535: }
1.27 markus 536: }
537:
538: Newkeys *
539: kex_get_newkeys(int mode)
540: {
1.30 markus 541: Newkeys *ret;
542:
543: ret = current_keys[mode];
544: current_keys[mode] = NULL;
545: return ret;
1.57 djm 546: }
547:
548: void
549: derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus,
550: u_int8_t cookie[8], u_int8_t id[16])
551: {
552: const EVP_MD *evp_md = EVP_md5();
553: EVP_MD_CTX md;
554: u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE];
555: int len;
556:
557: EVP_DigestInit(&md, evp_md);
558:
559: len = BN_num_bytes(host_modulus);
1.61 djm 560: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 561: fatal("%s: bad host modulus (len %d)", __func__, len);
562: BN_bn2bin(host_modulus, nbuf);
563: EVP_DigestUpdate(&md, nbuf, len);
564:
565: len = BN_num_bytes(server_modulus);
1.61 djm 566: if (len < (512 / 8) || (u_int)len > sizeof(nbuf))
1.57 djm 567: fatal("%s: bad server modulus (len %d)", __func__, len);
568: BN_bn2bin(server_modulus, nbuf);
569: EVP_DigestUpdate(&md, nbuf, len);
570:
571: EVP_DigestUpdate(&md, cookie, 8);
572:
1.58 djm 573: EVP_DigestFinal(&md, obuf, NULL);
1.57 djm 574: memcpy(id, obuf, 16);
575:
576: memset(nbuf, 0, sizeof(nbuf));
577: memset(obuf, 0, sizeof(obuf));
578: memset(&md, 0, sizeof(md));
1.1 markus 579: }
1.26 markus 580:
1.84 djm 581: #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) || defined(DEBUG_KEXECDH)
1.26 markus 582: void
583: dump_digest(char *msg, u_char *digest, int len)
584: {
1.84 djm 585: int i;
1.26 markus 586:
587: fprintf(stderr, "%s\n", msg);
1.77 stevesk 588: for (i = 0; i < len; i++) {
1.26 markus 589: fprintf(stderr, "%02x", digest[i]);
590: if (i%32 == 31)
591: fprintf(stderr, "\n");
592: else if (i%8 == 7)
593: fprintf(stderr, " ");
594: }
595: fprintf(stderr, "\n");
596: }
597: #endif
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