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4f8c6159 | 1 | /* |
a96070d4 | 2 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
4f8c6159 | 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. | |
4f8c6159 | 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" | |
ca75d7de | 26 | RCSID("$OpenBSD: kex.c,v 1.60 2004/06/21 17:36:31 avsm Exp $"); |
4f8c6159 | 27 | |
28 | #include <openssl/crypto.h> | |
4f8c6159 | 29 | |
42f11eb2 | 30 | #include "ssh2.h" |
31 | #include "xmalloc.h" | |
32 | #include "buffer.h" | |
33 | #include "bufaux.h" | |
34 | #include "packet.h" | |
35 | #include "compat.h" | |
36 | #include "cipher.h" | |
4f8c6159 | 37 | #include "kex.h" |
fa08c86b | 38 | #include "key.h" |
42f11eb2 | 39 | #include "log.h" |
b2552997 | 40 | #include "mac.h" |
cab80f75 | 41 | #include "match.h" |
a5c9ffdb | 42 | #include "dispatch.h" |
1853d1ef | 43 | #include "monitor.h" |
4f8c6159 | 44 | |
71276795 | 45 | #define KEX_COOKIE_LEN 16 |
46 | ||
396c147e | 47 | /* prototype */ |
48 | static void kex_kexinit_finish(Kex *); | |
49 | static void kex_choose_conf(Kex *); | |
a5c9ffdb | 50 | |
51 | /* put algorithm proposal into buffer */ | |
396c147e | 52 | static void |
a5c9ffdb | 53 | kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) |
4f8c6159 | 54 | { |
4f8c6159 | 55 | int i; |
a5c9ffdb | 56 | |
57 | buffer_clear(b); | |
76bf34f1 | 58 | /* |
59 | * add a dummy cookie, the cookie will be overwritten by | |
60 | * kex_send_kexinit(), each time a kexinit is set | |
61 | */ | |
62 | for (i = 0; i < KEX_COOKIE_LEN; i++) | |
63 | buffer_put_char(b, 0); | |
4f8c6159 | 64 | for (i = 0; i < PROPOSAL_MAX; i++) |
a5c9ffdb | 65 | buffer_put_cstring(b, proposal[i]); |
66 | buffer_put_char(b, 0); /* first_kex_packet_follows */ | |
67 | buffer_put_int(b, 0); /* uint32 reserved */ | |
4f8c6159 | 68 | } |
69 | ||
a5c9ffdb | 70 | /* parse buffer and return algorithm proposal */ |
396c147e | 71 | static char ** |
eed8e583 | 72 | kex_buf2prop(Buffer *raw, int *first_kex_follows) |
71276795 | 73 | { |
a5c9ffdb | 74 | Buffer b; |
71276795 | 75 | int i; |
a5c9ffdb | 76 | char **proposal; |
71276795 | 77 | |
a5c9ffdb | 78 | proposal = xmalloc(PROPOSAL_MAX * sizeof(char *)); |
79 | ||
80 | buffer_init(&b); | |
81 | buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); | |
71276795 | 82 | /* skip cookie */ |
83 | for (i = 0; i < KEX_COOKIE_LEN; i++) | |
a5c9ffdb | 84 | buffer_get_char(&b); |
71276795 | 85 | /* extract kex init proposal strings */ |
86 | for (i = 0; i < PROPOSAL_MAX; i++) { | |
a5c9ffdb | 87 | proposal[i] = buffer_get_string(&b,NULL); |
88 | debug2("kex_parse_kexinit: %s", proposal[i]); | |
71276795 | 89 | } |
a5c9ffdb | 90 | /* first kex follows / reserved */ |
91 | i = buffer_get_char(&b); | |
eed8e583 | 92 | if (first_kex_follows != NULL) |
93 | *first_kex_follows = i; | |
a5c9ffdb | 94 | debug2("kex_parse_kexinit: first_kex_follows %d ", i); |
95 | i = buffer_get_int(&b); | |
96 | debug2("kex_parse_kexinit: reserved %d ", i); | |
97 | buffer_free(&b); | |
98 | return proposal; | |
71276795 | 99 | } |
100 | ||
396c147e | 101 | static void |
a5c9ffdb | 102 | kex_prop_free(char **proposal) |
4f8c6159 | 103 | { |
104 | int i; | |
a5c9ffdb | 105 | |
106 | for (i = 0; i < PROPOSAL_MAX; i++) | |
107 | xfree(proposal[i]); | |
108 | xfree(proposal); | |
4f8c6159 | 109 | } |
110 | ||
396c147e | 111 | static void |
7819b5c3 | 112 | kex_protocol_error(int type, u_int32_t seq, void *ctxt) |
4f8c6159 | 113 | { |
7819b5c3 | 114 | error("Hm, kex protocol error: type %d seq %u", type, seq); |
a5c9ffdb | 115 | } |
4f8c6159 | 116 | |
396c147e | 117 | static void |
9d726f16 | 118 | kex_reset_dispatch(void) |
7a37c112 | 119 | { |
6367063f | 120 | dispatch_range(SSH2_MSG_TRANSPORT_MIN, |
121 | SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); | |
9d726f16 | 122 | dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); |
7a37c112 | 123 | } |
124 | ||
a5c9ffdb | 125 | void |
d8ee838b | 126 | kex_finish(Kex *kex) |
a5c9ffdb | 127 | { |
9d726f16 | 128 | kex_reset_dispatch(); |
d8ee838b | 129 | |
a5c9ffdb | 130 | packet_start(SSH2_MSG_NEWKEYS); |
131 | packet_send(); | |
132 | /* packet_write_wait(); */ | |
133 | debug("SSH2_MSG_NEWKEYS sent"); | |
4f8c6159 | 134 | |
a77673cc | 135 | debug("expecting SSH2_MSG_NEWKEYS"); |
54a5250f | 136 | packet_read_expect(SSH2_MSG_NEWKEYS); |
b967d870 | 137 | packet_check_eom(); |
a5c9ffdb | 138 | debug("SSH2_MSG_NEWKEYS received"); |
a7ca6275 | 139 | |
c422989b | 140 | kex->done = 1; |
a5c9ffdb | 141 | buffer_clear(&kex->peer); |
d1ac6175 | 142 | /* buffer_clear(&kex->my); */ |
a5c9ffdb | 143 | kex->flags &= ~KEX_INIT_SENT; |
a7ca6275 | 144 | xfree(kex->name); |
145 | kex->name = NULL; | |
4f8c6159 | 146 | } |
147 | ||
a5c9ffdb | 148 | void |
149 | kex_send_kexinit(Kex *kex) | |
94ec8c6b | 150 | { |
ca75d7de | 151 | u_int32_t rnd = 0; |
76bf34f1 | 152 | u_char *cookie; |
153 | int i; | |
154 | ||
7a37c112 | 155 | if (kex == NULL) { |
156 | error("kex_send_kexinit: no kex, cannot rekey"); | |
157 | return; | |
158 | } | |
d8ee838b | 159 | if (kex->flags & KEX_INIT_SENT) { |
160 | debug("KEX_INIT_SENT"); | |
161 | return; | |
162 | } | |
c422989b | 163 | kex->done = 0; |
76bf34f1 | 164 | |
165 | /* generate a random cookie */ | |
166 | if (buffer_len(&kex->my) < KEX_COOKIE_LEN) | |
167 | fatal("kex_send_kexinit: kex proposal too short"); | |
168 | cookie = buffer_ptr(&kex->my); | |
169 | for (i = 0; i < KEX_COOKIE_LEN; i++) { | |
170 | if (i % 4 == 0) | |
ca75d7de | 171 | rnd = arc4random(); |
172 | cookie[i] = rnd; | |
173 | rnd >>= 8; | |
76bf34f1 | 174 | } |
a5c9ffdb | 175 | packet_start(SSH2_MSG_KEXINIT); |
176 | packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my)); | |
177 | packet_send(); | |
178 | debug("SSH2_MSG_KEXINIT sent"); | |
179 | kex->flags |= KEX_INIT_SENT; | |
180 | } | |
2b87da3b | 181 | |
a5c9ffdb | 182 | void |
7819b5c3 | 183 | kex_input_kexinit(int type, u_int32_t seq, void *ctxt) |
a5c9ffdb | 184 | { |
185 | char *ptr; | |
186 | int dlen; | |
bbb4cc1b | 187 | int i; |
a5c9ffdb | 188 | Kex *kex = (Kex *)ctxt; |
94ec8c6b | 189 | |
a5c9ffdb | 190 | debug("SSH2_MSG_KEXINIT received"); |
7a37c112 | 191 | if (kex == NULL) |
192 | fatal("kex_input_kexinit: no kex, cannot rekey"); | |
94ec8c6b | 193 | |
a5c9ffdb | 194 | ptr = packet_get_raw(&dlen); |
195 | buffer_append(&kex->peer, ptr, dlen); | |
94ec8c6b | 196 | |
bbb4cc1b | 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)); | |
1169c3df | 202 | (void) packet_get_char(); |
203 | (void) packet_get_int(); | |
95500969 | 204 | packet_check_eom(); |
bbb4cc1b | 205 | |
a5c9ffdb | 206 | kex_kexinit_finish(kex); |
94ec8c6b | 207 | } |
208 | ||
a5c9ffdb | 209 | Kex * |
d8ee838b | 210 | kex_setup(char *proposal[PROPOSAL_MAX]) |
4f8c6159 | 211 | { |
a5c9ffdb | 212 | Kex *kex; |
4f8c6159 | 213 | |
a5c9ffdb | 214 | kex = xmalloc(sizeof(*kex)); |
215 | memset(kex, 0, sizeof(*kex)); | |
216 | buffer_init(&kex->peer); | |
217 | buffer_init(&kex->my); | |
218 | kex_prop2buf(&kex->my, proposal); | |
c422989b | 219 | kex->done = 0; |
a5c9ffdb | 220 | |
221 | kex_send_kexinit(kex); /* we start */ | |
9d726f16 | 222 | kex_reset_dispatch(); |
7a37c112 | 223 | |
a5c9ffdb | 224 | return kex; |
225 | } | |
4f8c6159 | 226 | |
396c147e | 227 | static void |
a5c9ffdb | 228 | kex_kexinit_finish(Kex *kex) |
229 | { | |
230 | if (!(kex->flags & KEX_INIT_SENT)) | |
231 | kex_send_kexinit(kex); | |
232 | ||
233 | kex_choose_conf(kex); | |
234 | ||
98a58eda | 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 { | |
a5c9ffdb | 239 | fatal("Unsupported key exchange %d", kex->kex_type); |
4f8c6159 | 240 | } |
4f8c6159 | 241 | } |
242 | ||
396c147e | 243 | static void |
4f8c6159 | 244 | choose_enc(Enc *enc, char *client, char *server) |
245 | { | |
cab80f75 | 246 | char *name = match_list(client, server, NULL); |
4f8c6159 | 247 | if (name == NULL) |
248 | fatal("no matching cipher found: client %s server %s", client, server); | |
3ee832e5 | 249 | if ((enc->cipher = cipher_by_name(name)) == NULL) |
94ec8c6b | 250 | fatal("matching cipher is not supported: %s", name); |
4f8c6159 | 251 | enc->name = name; |
252 | enc->enabled = 0; | |
253 | enc->iv = NULL; | |
254 | enc->key = NULL; | |
3ee832e5 | 255 | enc->key_len = cipher_keylen(enc->cipher); |
256 | enc->block_size = cipher_blocksize(enc->cipher); | |
4f8c6159 | 257 | } |
396c147e | 258 | static void |
4f8c6159 | 259 | choose_mac(Mac *mac, char *client, char *server) |
260 | { | |
cab80f75 | 261 | char *name = match_list(client, server, NULL); |
4f8c6159 | 262 | if (name == NULL) |
263 | fatal("no matching mac found: client %s server %s", client, server); | |
b2552997 | 264 | if (mac_init(mac, name) < 0) |
4f8c6159 | 265 | fatal("unsupported mac %s", name); |
b2552997 | 266 | /* truncate the key */ |
267 | if (datafellows & SSH_BUG_HMAC) | |
268 | mac->key_len = 16; | |
4f8c6159 | 269 | mac->name = name; |
4f8c6159 | 270 | mac->key = NULL; |
271 | mac->enabled = 0; | |
272 | } | |
396c147e | 273 | static void |
4f8c6159 | 274 | choose_comp(Comp *comp, char *client, char *server) |
275 | { | |
cab80f75 | 276 | char *name = match_list(client, server, NULL); |
4f8c6159 | 277 | if (name == NULL) |
278 | fatal("no matching comp found: client %s server %s", client, server); | |
279 | if (strcmp(name, "zlib") == 0) { | |
280 | comp->type = 1; | |
281 | } else if (strcmp(name, "none") == 0) { | |
282 | comp->type = 0; | |
283 | } else { | |
284 | fatal("unsupported comp %s", name); | |
285 | } | |
286 | comp->name = name; | |
287 | } | |
396c147e | 288 | static void |
4f8c6159 | 289 | choose_kex(Kex *k, char *client, char *server) |
290 | { | |
cab80f75 | 291 | k->name = match_list(client, server, NULL); |
4f8c6159 | 292 | if (k->name == NULL) |
293 | fatal("no kex alg"); | |
94ec8c6b | 294 | if (strcmp(k->name, KEX_DH1) == 0) { |
98a58eda | 295 | k->kex_type = KEX_DH_GRP1_SHA1; |
41e5bd9a | 296 | } else if (strcmp(k->name, KEX_DH14) == 0) { |
297 | k->kex_type = KEX_DH_GRP14_SHA1; | |
94ec8c6b | 298 | } else if (strcmp(k->name, KEX_DHGEX) == 0) { |
98a58eda | 299 | k->kex_type = KEX_DH_GEX_SHA1; |
94ec8c6b | 300 | } else |
4f8c6159 | 301 | fatal("bad kex alg %s", k->name); |
302 | } | |
396c147e | 303 | static void |
4f8c6159 | 304 | choose_hostkeyalg(Kex *k, char *client, char *server) |
305 | { | |
cab80f75 | 306 | char *hostkeyalg = match_list(client, server, NULL); |
fa08c86b | 307 | if (hostkeyalg == NULL) |
4f8c6159 | 308 | fatal("no hostkey alg"); |
fa08c86b | 309 | k->hostkey_type = key_type_from_name(hostkeyalg); |
310 | if (k->hostkey_type == KEY_UNSPEC) | |
311 | fatal("bad hostkey alg '%s'", hostkeyalg); | |
eea39c02 | 312 | xfree(hostkeyalg); |
4f8c6159 | 313 | } |
314 | ||
aff51935 | 315 | static int |
eed8e583 | 316 | proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) |
317 | { | |
318 | static int check[] = { | |
319 | PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 | |
320 | }; | |
321 | int *idx; | |
322 | char *p; | |
323 | ||
324 | for (idx = &check[0]; *idx != -1; idx++) { | |
325 | if ((p = strchr(my[*idx], ',')) != NULL) | |
326 | *p = '\0'; | |
327 | if ((p = strchr(peer[*idx], ',')) != NULL) | |
328 | *p = '\0'; | |
329 | if (strcmp(my[*idx], peer[*idx]) != 0) { | |
330 | debug2("proposal mismatch: my %s peer %s", | |
331 | my[*idx], peer[*idx]); | |
332 | return (0); | |
333 | } | |
334 | } | |
335 | debug2("proposals match"); | |
336 | return (1); | |
337 | } | |
338 | ||
396c147e | 339 | static void |
d1ac6175 | 340 | kex_choose_conf(Kex *kex) |
4f8c6159 | 341 | { |
d1ac6175 | 342 | Newkeys *newkeys; |
a5c9ffdb | 343 | char **my, **peer; |
344 | char **cprop, **sprop; | |
d1ac6175 | 345 | int nenc, nmac, ncomp; |
4f8c6159 | 346 | int mode; |
347 | int ctos; /* direction: if true client-to-server */ | |
348 | int need; | |
eed8e583 | 349 | int first_kex_follows, type; |
4f8c6159 | 350 | |
eed8e583 | 351 | my = kex_buf2prop(&kex->my, NULL); |
352 | peer = kex_buf2prop(&kex->peer, &first_kex_follows); | |
a5c9ffdb | 353 | |
d1ac6175 | 354 | if (kex->server) { |
a5c9ffdb | 355 | cprop=peer; |
356 | sprop=my; | |
357 | } else { | |
358 | cprop=my; | |
359 | sprop=peer; | |
360 | } | |
4f8c6159 | 361 | |
c422989b | 362 | /* Algorithm Negotiation */ |
4f8c6159 | 363 | for (mode = 0; mode < MODE_MAX; mode++) { |
d1ac6175 | 364 | newkeys = xmalloc(sizeof(*newkeys)); |
365 | memset(newkeys, 0, sizeof(*newkeys)); | |
c422989b | 366 | kex->newkeys[mode] = newkeys; |
d1ac6175 | 367 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
4f8c6159 | 368 | nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC; |
369 | nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC; | |
370 | ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC; | |
d1ac6175 | 371 | choose_enc (&newkeys->enc, cprop[nenc], sprop[nenc]); |
372 | choose_mac (&newkeys->mac, cprop[nmac], sprop[nmac]); | |
373 | choose_comp(&newkeys->comp, cprop[ncomp], sprop[ncomp]); | |
4f8c6159 | 374 | debug("kex: %s %s %s %s", |
375 | ctos ? "client->server" : "server->client", | |
d1ac6175 | 376 | newkeys->enc.name, |
377 | newkeys->mac.name, | |
378 | newkeys->comp.name); | |
4f8c6159 | 379 | } |
d1ac6175 | 380 | choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); |
381 | choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], | |
4f8c6159 | 382 | sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); |
4f8c6159 | 383 | need = 0; |
384 | for (mode = 0; mode < MODE_MAX; mode++) { | |
c422989b | 385 | newkeys = kex->newkeys[mode]; |
3ee832e5 | 386 | if (need < newkeys->enc.key_len) |
387 | need = newkeys->enc.key_len; | |
388 | if (need < newkeys->enc.block_size) | |
389 | need = newkeys->enc.block_size; | |
d1ac6175 | 390 | if (need < newkeys->mac.key_len) |
391 | need = newkeys->mac.key_len; | |
4f8c6159 | 392 | } |
71276795 | 393 | /* XXX need runden? */ |
d1ac6175 | 394 | kex->we_need = need; |
a5c9ffdb | 395 | |
eed8e583 | 396 | /* ignore the next message if the proposals do not match */ |
aff51935 | 397 | if (first_kex_follows && !proposals_match(my, peer) && |
519bdfe8 | 398 | !(datafellows & SSH_BUG_FIRSTKEX)) { |
eed8e583 | 399 | type = packet_read(); |
400 | debug2("skipping next packet (type %u)", type); | |
401 | } | |
402 | ||
a5c9ffdb | 403 | kex_prop_free(my); |
404 | kex_prop_free(peer); | |
a5c9ffdb | 405 | } |
406 | ||
396c147e | 407 | static u_char * |
d1ac6175 | 408 | derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret) |
a5c9ffdb | 409 | { |
410 | Buffer b; | |
714954dc | 411 | const EVP_MD *evp_md = EVP_sha1(); |
a5c9ffdb | 412 | EVP_MD_CTX md; |
413 | char c = id; | |
414 | int have; | |
a209a158 | 415 | int mdsz = EVP_MD_size(evp_md); |
c422989b | 416 | u_char *digest = xmalloc(roundup(need, mdsz)); |
a5c9ffdb | 417 | |
418 | buffer_init(&b); | |
419 | buffer_put_bignum2(&b, shared_secret); | |
420 | ||
c422989b | 421 | /* K1 = HASH(K || H || "A" || session_id) */ |
a5c9ffdb | 422 | EVP_DigestInit(&md, evp_md); |
eef7adcb | 423 | if (!(datafellows & SSH_BUG_DERIVEKEY)) |
424 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); | |
c422989b | 425 | EVP_DigestUpdate(&md, hash, mdsz); |
426 | EVP_DigestUpdate(&md, &c, 1); | |
d1ac6175 | 427 | EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
a5c9ffdb | 428 | EVP_DigestFinal(&md, digest, NULL); |
429 | ||
c422989b | 430 | /* |
431 | * expand key: | |
432 | * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) | |
433 | * Key = K1 || K2 || ... || Kn | |
434 | */ | |
a5c9ffdb | 435 | for (have = mdsz; need > have; have += mdsz) { |
436 | EVP_DigestInit(&md, evp_md); | |
eef7adcb | 437 | if (!(datafellows & SSH_BUG_DERIVEKEY)) |
438 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); | |
a5c9ffdb | 439 | EVP_DigestUpdate(&md, hash, mdsz); |
440 | EVP_DigestUpdate(&md, digest, have); | |
441 | EVP_DigestFinal(&md, digest + have, NULL); | |
442 | } | |
443 | buffer_free(&b); | |
444 | #ifdef DEBUG_KEX | |
445 | fprintf(stderr, "key '%c'== ", c); | |
446 | dump_digest("key", digest, need); | |
447 | #endif | |
448 | return digest; | |
4f8c6159 | 449 | } |
450 | ||
c422989b | 451 | Newkeys *current_keys[MODE_MAX]; |
d1ac6175 | 452 | |
cab80f75 | 453 | #define NKEYS 6 |
a5c9ffdb | 454 | void |
d1ac6175 | 455 | kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret) |
4f8c6159 | 456 | { |
1e3b8b07 | 457 | u_char *keys[NKEYS]; |
d1ac6175 | 458 | int i, mode, ctos; |
4f8c6159 | 459 | |
460 | for (i = 0; i < NKEYS; i++) | |
d1ac6175 | 461 | keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, shared_secret); |
4f8c6159 | 462 | |
a77673cc | 463 | debug2("kex_derive_keys"); |
4f8c6159 | 464 | for (mode = 0; mode < MODE_MAX; mode++) { |
c422989b | 465 | current_keys[mode] = kex->newkeys[mode]; |
466 | kex->newkeys[mode] = NULL; | |
d1ac6175 | 467 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
c422989b | 468 | current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; |
469 | current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; | |
470 | current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; | |
4f8c6159 | 471 | } |
4f8c6159 | 472 | } |
a5c9ffdb | 473 | |
d1ac6175 | 474 | Newkeys * |
475 | kex_get_newkeys(int mode) | |
476 | { | |
c422989b | 477 | Newkeys *ret; |
478 | ||
479 | ret = current_keys[mode]; | |
480 | current_keys[mode] = NULL; | |
481 | return ret; | |
d1ac6175 | 482 | } |
483 | ||
8bbf1fa6 | 484 | void |
485 | derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus, | |
486 | u_int8_t cookie[8], u_int8_t id[16]) | |
487 | { | |
488 | const EVP_MD *evp_md = EVP_md5(); | |
489 | EVP_MD_CTX md; | |
490 | u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE]; | |
491 | int len; | |
492 | ||
493 | EVP_DigestInit(&md, evp_md); | |
494 | ||
495 | len = BN_num_bytes(host_modulus); | |
496 | if (len < (512 / 8) || len > sizeof(nbuf)) | |
497 | fatal("%s: bad host modulus (len %d)", __func__, len); | |
498 | BN_bn2bin(host_modulus, nbuf); | |
499 | EVP_DigestUpdate(&md, nbuf, len); | |
500 | ||
501 | len = BN_num_bytes(server_modulus); | |
502 | if (len < (512 / 8) || len > sizeof(nbuf)) | |
503 | fatal("%s: bad server modulus (len %d)", __func__, len); | |
504 | BN_bn2bin(server_modulus, nbuf); | |
505 | EVP_DigestUpdate(&md, nbuf, len); | |
506 | ||
507 | EVP_DigestUpdate(&md, cookie, 8); | |
508 | ||
59657003 | 509 | EVP_DigestFinal(&md, obuf, NULL); |
8bbf1fa6 | 510 | memcpy(id, obuf, 16); |
511 | ||
512 | memset(nbuf, 0, sizeof(nbuf)); | |
513 | memset(obuf, 0, sizeof(obuf)); | |
514 | memset(&md, 0, sizeof(md)); | |
515 | } | |
516 | ||
a5c9ffdb | 517 | #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) |
518 | void | |
519 | dump_digest(char *msg, u_char *digest, int len) | |
520 | { | |
521 | int i; | |
522 | ||
523 | fprintf(stderr, "%s\n", msg); | |
6aacefa7 | 524 | for (i = 0; i< len; i++) { |
a5c9ffdb | 525 | fprintf(stderr, "%02x", digest[i]); |
526 | if (i%32 == 31) | |
527 | fprintf(stderr, "\n"); | |
528 | else if (i%8 == 7) | |
529 | fprintf(stderr, " "); | |
530 | } | |
531 | fprintf(stderr, "\n"); | |
532 | } | |
533 | #endif |