]>
Commit | Line | Data |
---|---|---|
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" | |
2ff8003a | 26 | RCSID("$OpenBSD: kex.c,v 1.66 2006/03/07 09:07:40 djm 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 | ||
2ff8003a | 47 | extern const EVP_MD *evp_ssh_sha256(void); |
48 | ||
396c147e | 49 | /* prototype */ |
50 | static void kex_kexinit_finish(Kex *); | |
51 | static void kex_choose_conf(Kex *); | |
a5c9ffdb | 52 | |
53 | /* put algorithm proposal into buffer */ | |
396c147e | 54 | static void |
a5c9ffdb | 55 | kex_prop2buf(Buffer *b, char *proposal[PROPOSAL_MAX]) |
4f8c6159 | 56 | { |
2ceb8101 | 57 | u_int i; |
a5c9ffdb | 58 | |
59 | buffer_clear(b); | |
76bf34f1 | 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); | |
4f8c6159 | 66 | for (i = 0; i < PROPOSAL_MAX; i++) |
a5c9ffdb | 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 */ | |
4f8c6159 | 70 | } |
71 | ||
a5c9ffdb | 72 | /* parse buffer and return algorithm proposal */ |
396c147e | 73 | static char ** |
eed8e583 | 74 | kex_buf2prop(Buffer *raw, int *first_kex_follows) |
71276795 | 75 | { |
a5c9ffdb | 76 | Buffer b; |
71276795 | 77 | int i; |
a5c9ffdb | 78 | char **proposal; |
71276795 | 79 | |
a5c9ffdb | 80 | proposal = xmalloc(PROPOSAL_MAX * sizeof(char *)); |
81 | ||
82 | buffer_init(&b); | |
83 | buffer_append(&b, buffer_ptr(raw), buffer_len(raw)); | |
71276795 | 84 | /* skip cookie */ |
85 | for (i = 0; i < KEX_COOKIE_LEN; i++) | |
a5c9ffdb | 86 | buffer_get_char(&b); |
71276795 | 87 | /* extract kex init proposal strings */ |
88 | for (i = 0; i < PROPOSAL_MAX; i++) { | |
a5c9ffdb | 89 | proposal[i] = buffer_get_string(&b,NULL); |
90 | debug2("kex_parse_kexinit: %s", proposal[i]); | |
71276795 | 91 | } |
a5c9ffdb | 92 | /* first kex follows / reserved */ |
93 | i = buffer_get_char(&b); | |
eed8e583 | 94 | if (first_kex_follows != NULL) |
95 | *first_kex_follows = i; | |
a5c9ffdb | 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; | |
71276795 | 101 | } |
102 | ||
396c147e | 103 | static void |
a5c9ffdb | 104 | kex_prop_free(char **proposal) |
4f8c6159 | 105 | { |
2ceb8101 | 106 | u_int i; |
a5c9ffdb | 107 | |
108 | for (i = 0; i < PROPOSAL_MAX; i++) | |
109 | xfree(proposal[i]); | |
110 | xfree(proposal); | |
4f8c6159 | 111 | } |
112 | ||
396c147e | 113 | static void |
7819b5c3 | 114 | kex_protocol_error(int type, u_int32_t seq, void *ctxt) |
4f8c6159 | 115 | { |
7819b5c3 | 116 | error("Hm, kex protocol error: type %d seq %u", type, seq); |
a5c9ffdb | 117 | } |
4f8c6159 | 118 | |
396c147e | 119 | static void |
9d726f16 | 120 | kex_reset_dispatch(void) |
7a37c112 | 121 | { |
6367063f | 122 | dispatch_range(SSH2_MSG_TRANSPORT_MIN, |
123 | SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error); | |
9d726f16 | 124 | dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); |
7a37c112 | 125 | } |
126 | ||
a5c9ffdb | 127 | void |
d8ee838b | 128 | kex_finish(Kex *kex) |
a5c9ffdb | 129 | { |
9d726f16 | 130 | kex_reset_dispatch(); |
d8ee838b | 131 | |
a5c9ffdb | 132 | packet_start(SSH2_MSG_NEWKEYS); |
133 | packet_send(); | |
134 | /* packet_write_wait(); */ | |
135 | debug("SSH2_MSG_NEWKEYS sent"); | |
4f8c6159 | 136 | |
a77673cc | 137 | debug("expecting SSH2_MSG_NEWKEYS"); |
54a5250f | 138 | packet_read_expect(SSH2_MSG_NEWKEYS); |
b967d870 | 139 | packet_check_eom(); |
a5c9ffdb | 140 | debug("SSH2_MSG_NEWKEYS received"); |
a7ca6275 | 141 | |
c422989b | 142 | kex->done = 1; |
a5c9ffdb | 143 | buffer_clear(&kex->peer); |
d1ac6175 | 144 | /* buffer_clear(&kex->my); */ |
a5c9ffdb | 145 | kex->flags &= ~KEX_INIT_SENT; |
a7ca6275 | 146 | xfree(kex->name); |
147 | kex->name = NULL; | |
4f8c6159 | 148 | } |
149 | ||
a5c9ffdb | 150 | void |
151 | kex_send_kexinit(Kex *kex) | |
94ec8c6b | 152 | { |
ca75d7de | 153 | u_int32_t rnd = 0; |
76bf34f1 | 154 | u_char *cookie; |
2ceb8101 | 155 | u_int i; |
76bf34f1 | 156 | |
7a37c112 | 157 | if (kex == NULL) { |
158 | error("kex_send_kexinit: no kex, cannot rekey"); | |
159 | return; | |
160 | } | |
d8ee838b | 161 | if (kex->flags & KEX_INIT_SENT) { |
162 | debug("KEX_INIT_SENT"); | |
163 | return; | |
164 | } | |
c422989b | 165 | kex->done = 0; |
76bf34f1 | 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) | |
ca75d7de | 173 | rnd = arc4random(); |
174 | cookie[i] = rnd; | |
175 | rnd >>= 8; | |
76bf34f1 | 176 | } |
a5c9ffdb | 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; | |
182 | } | |
2b87da3b | 183 | |
a5c9ffdb | 184 | void |
7819b5c3 | 185 | kex_input_kexinit(int type, u_int32_t seq, void *ctxt) |
a5c9ffdb | 186 | { |
187 | char *ptr; | |
2ceb8101 | 188 | u_int i, dlen; |
a5c9ffdb | 189 | Kex *kex = (Kex *)ctxt; |
94ec8c6b | 190 | |
a5c9ffdb | 191 | debug("SSH2_MSG_KEXINIT received"); |
7a37c112 | 192 | if (kex == NULL) |
193 | fatal("kex_input_kexinit: no kex, cannot rekey"); | |
94ec8c6b | 194 | |
a5c9ffdb | 195 | ptr = packet_get_raw(&dlen); |
196 | buffer_append(&kex->peer, ptr, dlen); | |
94ec8c6b | 197 | |
bbb4cc1b | 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)); | |
1169c3df | 203 | (void) packet_get_char(); |
204 | (void) packet_get_int(); | |
95500969 | 205 | packet_check_eom(); |
bbb4cc1b | 206 | |
a5c9ffdb | 207 | kex_kexinit_finish(kex); |
94ec8c6b | 208 | } |
209 | ||
a5c9ffdb | 210 | Kex * |
d8ee838b | 211 | kex_setup(char *proposal[PROPOSAL_MAX]) |
4f8c6159 | 212 | { |
a5c9ffdb | 213 | Kex *kex; |
4f8c6159 | 214 | |
a5c9ffdb | 215 | kex = xmalloc(sizeof(*kex)); |
216 | memset(kex, 0, sizeof(*kex)); | |
217 | buffer_init(&kex->peer); | |
218 | buffer_init(&kex->my); | |
219 | kex_prop2buf(&kex->my, proposal); | |
c422989b | 220 | kex->done = 0; |
a5c9ffdb | 221 | |
222 | kex_send_kexinit(kex); /* we start */ | |
9d726f16 | 223 | kex_reset_dispatch(); |
7a37c112 | 224 | |
a5c9ffdb | 225 | return kex; |
226 | } | |
4f8c6159 | 227 | |
396c147e | 228 | static void |
a5c9ffdb | 229 | kex_kexinit_finish(Kex *kex) |
230 | { | |
231 | if (!(kex->flags & KEX_INIT_SENT)) | |
232 | kex_send_kexinit(kex); | |
233 | ||
234 | kex_choose_conf(kex); | |
235 | ||
98a58eda | 236 | if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX && |
237 | kex->kex[kex->kex_type] != NULL) { | |
238 | (kex->kex[kex->kex_type])(kex); | |
239 | } else { | |
a5c9ffdb | 240 | fatal("Unsupported key exchange %d", kex->kex_type); |
4f8c6159 | 241 | } |
4f8c6159 | 242 | } |
243 | ||
396c147e | 244 | static void |
4f8c6159 | 245 | choose_enc(Enc *enc, char *client, char *server) |
246 | { | |
cab80f75 | 247 | char *name = match_list(client, server, NULL); |
4f8c6159 | 248 | if (name == NULL) |
249 | fatal("no matching cipher found: client %s server %s", client, server); | |
3ee832e5 | 250 | if ((enc->cipher = cipher_by_name(name)) == NULL) |
94ec8c6b | 251 | fatal("matching cipher is not supported: %s", name); |
4f8c6159 | 252 | enc->name = name; |
253 | enc->enabled = 0; | |
254 | enc->iv = NULL; | |
255 | enc->key = NULL; | |
3ee832e5 | 256 | enc->key_len = cipher_keylen(enc->cipher); |
257 | enc->block_size = cipher_blocksize(enc->cipher); | |
4f8c6159 | 258 | } |
396c147e | 259 | static void |
4f8c6159 | 260 | choose_mac(Mac *mac, char *client, char *server) |
261 | { | |
cab80f75 | 262 | char *name = match_list(client, server, NULL); |
4f8c6159 | 263 | if (name == NULL) |
264 | fatal("no matching mac found: client %s server %s", client, server); | |
b2552997 | 265 | if (mac_init(mac, name) < 0) |
4f8c6159 | 266 | fatal("unsupported mac %s", name); |
b2552997 | 267 | /* truncate the key */ |
268 | if (datafellows & SSH_BUG_HMAC) | |
269 | mac->key_len = 16; | |
4f8c6159 | 270 | mac->name = name; |
4f8c6159 | 271 | mac->key = NULL; |
272 | mac->enabled = 0; | |
273 | } | |
396c147e | 274 | static void |
4f8c6159 | 275 | choose_comp(Comp *comp, char *client, char *server) |
276 | { | |
cab80f75 | 277 | char *name = match_list(client, server, NULL); |
4f8c6159 | 278 | if (name == NULL) |
279 | fatal("no matching comp found: client %s server %s", client, server); | |
07200973 | 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; | |
4f8c6159 | 284 | } else if (strcmp(name, "none") == 0) { |
07200973 | 285 | comp->type = COMP_NONE; |
4f8c6159 | 286 | } else { |
287 | fatal("unsupported comp %s", name); | |
288 | } | |
289 | comp->name = name; | |
290 | } | |
396c147e | 291 | static void |
4f8c6159 | 292 | choose_kex(Kex *k, char *client, char *server) |
293 | { | |
cab80f75 | 294 | k->name = match_list(client, server, NULL); |
4f8c6159 | 295 | if (k->name == NULL) |
296 | fatal("no kex alg"); | |
94ec8c6b | 297 | if (strcmp(k->name, KEX_DH1) == 0) { |
98a58eda | 298 | k->kex_type = KEX_DH_GRP1_SHA1; |
47e5dc72 | 299 | k->evp_md = EVP_sha1(); |
41e5bd9a | 300 | } else if (strcmp(k->name, KEX_DH14) == 0) { |
301 | k->kex_type = KEX_DH_GRP14_SHA1; | |
47e5dc72 | 302 | k->evp_md = EVP_sha1(); |
303 | } else if (strcmp(k->name, KEX_DHGEX_SHA1) == 0) { | |
98a58eda | 304 | k->kex_type = KEX_DH_GEX_SHA1; |
47e5dc72 | 305 | k->evp_md = EVP_sha1(); |
2ff8003a | 306 | } else if (strcmp(k->name, KEX_DHGEX_SHA256) == 0) { |
307 | k->kex_type = KEX_DH_GEX_SHA256; | |
308 | k->evp_md = evp_ssh_sha256(); | |
94ec8c6b | 309 | } else |
4f8c6159 | 310 | fatal("bad kex alg %s", k->name); |
311 | } | |
47e5dc72 | 312 | |
396c147e | 313 | static void |
4f8c6159 | 314 | choose_hostkeyalg(Kex *k, char *client, char *server) |
315 | { | |
cab80f75 | 316 | char *hostkeyalg = match_list(client, server, NULL); |
fa08c86b | 317 | if (hostkeyalg == NULL) |
4f8c6159 | 318 | fatal("no hostkey alg"); |
fa08c86b | 319 | k->hostkey_type = key_type_from_name(hostkeyalg); |
320 | if (k->hostkey_type == KEY_UNSPEC) | |
321 | fatal("bad hostkey alg '%s'", hostkeyalg); | |
eea39c02 | 322 | xfree(hostkeyalg); |
4f8c6159 | 323 | } |
324 | ||
aff51935 | 325 | static int |
eed8e583 | 326 | proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX]) |
327 | { | |
328 | static int check[] = { | |
329 | PROPOSAL_KEX_ALGS, PROPOSAL_SERVER_HOST_KEY_ALGS, -1 | |
330 | }; | |
331 | int *idx; | |
332 | char *p; | |
333 | ||
334 | for (idx = &check[0]; *idx != -1; idx++) { | |
335 | if ((p = strchr(my[*idx], ',')) != NULL) | |
336 | *p = '\0'; | |
337 | if ((p = strchr(peer[*idx], ',')) != NULL) | |
338 | *p = '\0'; | |
339 | if (strcmp(my[*idx], peer[*idx]) != 0) { | |
340 | debug2("proposal mismatch: my %s peer %s", | |
341 | my[*idx], peer[*idx]); | |
342 | return (0); | |
343 | } | |
344 | } | |
345 | debug2("proposals match"); | |
346 | return (1); | |
347 | } | |
348 | ||
396c147e | 349 | static void |
d1ac6175 | 350 | kex_choose_conf(Kex *kex) |
4f8c6159 | 351 | { |
d1ac6175 | 352 | Newkeys *newkeys; |
a5c9ffdb | 353 | char **my, **peer; |
354 | char **cprop, **sprop; | |
d1ac6175 | 355 | int nenc, nmac, ncomp; |
2ceb8101 | 356 | u_int mode, ctos, need; |
eed8e583 | 357 | int first_kex_follows, type; |
4f8c6159 | 358 | |
eed8e583 | 359 | my = kex_buf2prop(&kex->my, NULL); |
360 | peer = kex_buf2prop(&kex->peer, &first_kex_follows); | |
a5c9ffdb | 361 | |
d1ac6175 | 362 | if (kex->server) { |
a5c9ffdb | 363 | cprop=peer; |
364 | sprop=my; | |
365 | } else { | |
366 | cprop=my; | |
367 | sprop=peer; | |
368 | } | |
4f8c6159 | 369 | |
c422989b | 370 | /* Algorithm Negotiation */ |
4f8c6159 | 371 | for (mode = 0; mode < MODE_MAX; mode++) { |
d1ac6175 | 372 | newkeys = xmalloc(sizeof(*newkeys)); |
373 | memset(newkeys, 0, sizeof(*newkeys)); | |
c422989b | 374 | kex->newkeys[mode] = newkeys; |
d1ac6175 | 375 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
4f8c6159 | 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; | |
d1ac6175 | 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]); | |
4f8c6159 | 382 | debug("kex: %s %s %s %s", |
383 | ctos ? "client->server" : "server->client", | |
d1ac6175 | 384 | newkeys->enc.name, |
385 | newkeys->mac.name, | |
386 | newkeys->comp.name); | |
4f8c6159 | 387 | } |
d1ac6175 | 388 | choose_kex(kex, cprop[PROPOSAL_KEX_ALGS], sprop[PROPOSAL_KEX_ALGS]); |
389 | choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS], | |
4f8c6159 | 390 | sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]); |
4f8c6159 | 391 | need = 0; |
392 | for (mode = 0; mode < MODE_MAX; mode++) { | |
c422989b | 393 | newkeys = kex->newkeys[mode]; |
3ee832e5 | 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; | |
d1ac6175 | 398 | if (need < newkeys->mac.key_len) |
399 | need = newkeys->mac.key_len; | |
4f8c6159 | 400 | } |
71276795 | 401 | /* XXX need runden? */ |
d1ac6175 | 402 | kex->we_need = need; |
a5c9ffdb | 403 | |
eed8e583 | 404 | /* ignore the next message if the proposals do not match */ |
aff51935 | 405 | if (first_kex_follows && !proposals_match(my, peer) && |
4e2e5cfd | 406 | !(datafellows & SSH_BUG_FIRSTKEX)) { |
eed8e583 | 407 | type = packet_read(); |
408 | debug2("skipping next packet (type %u)", type); | |
409 | } | |
410 | ||
a5c9ffdb | 411 | kex_prop_free(my); |
412 | kex_prop_free(peer); | |
a5c9ffdb | 413 | } |
414 | ||
396c147e | 415 | static u_char * |
47e5dc72 | 416 | derive_key(Kex *kex, int id, u_int need, u_char *hash, u_int hashlen, |
417 | BIGNUM *shared_secret) | |
a5c9ffdb | 418 | { |
419 | Buffer b; | |
a5c9ffdb | 420 | EVP_MD_CTX md; |
421 | char c = id; | |
2ceb8101 | 422 | u_int have; |
47e5dc72 | 423 | int mdsz; |
2ceb8101 | 424 | u_char *digest; |
56964485 | 425 | |
47e5dc72 | 426 | if ((mdsz = EVP_MD_size(kex->evp_md)) <= 0) |
427 | fatal("bad kex md size %d", mdsz); | |
428 | digest = xmalloc(roundup(need, mdsz)); | |
a5c9ffdb | 429 | |
430 | buffer_init(&b); | |
431 | buffer_put_bignum2(&b, shared_secret); | |
432 | ||
c422989b | 433 | /* K1 = HASH(K || H || "A" || session_id) */ |
47e5dc72 | 434 | EVP_DigestInit(&md, kex->evp_md); |
eef7adcb | 435 | if (!(datafellows & SSH_BUG_DERIVEKEY)) |
436 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); | |
47e5dc72 | 437 | EVP_DigestUpdate(&md, hash, hashlen); |
c422989b | 438 | EVP_DigestUpdate(&md, &c, 1); |
d1ac6175 | 439 | EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len); |
a5c9ffdb | 440 | EVP_DigestFinal(&md, digest, NULL); |
441 | ||
c422989b | 442 | /* |
443 | * expand key: | |
444 | * Kn = HASH(K || H || K1 || K2 || ... || Kn-1) | |
445 | * Key = K1 || K2 || ... || Kn | |
446 | */ | |
a5c9ffdb | 447 | for (have = mdsz; need > have; have += mdsz) { |
47e5dc72 | 448 | EVP_DigestInit(&md, kex->evp_md); |
eef7adcb | 449 | if (!(datafellows & SSH_BUG_DERIVEKEY)) |
450 | EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); | |
47e5dc72 | 451 | EVP_DigestUpdate(&md, hash, hashlen); |
a5c9ffdb | 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; | |
4f8c6159 | 461 | } |
462 | ||
c422989b | 463 | Newkeys *current_keys[MODE_MAX]; |
d1ac6175 | 464 | |
cab80f75 | 465 | #define NKEYS 6 |
a5c9ffdb | 466 | void |
47e5dc72 | 467 | kex_derive_keys(Kex *kex, u_char *hash, u_int hashlen, BIGNUM *shared_secret) |
4f8c6159 | 468 | { |
1e3b8b07 | 469 | u_char *keys[NKEYS]; |
2ceb8101 | 470 | u_int i, mode, ctos; |
4f8c6159 | 471 | |
47e5dc72 | 472 | for (i = 0; i < NKEYS; i++) { |
473 | keys[i] = derive_key(kex, 'A'+i, kex->we_need, hash, hashlen, | |
474 | shared_secret); | |
475 | } | |
4f8c6159 | 476 | |
a77673cc | 477 | debug2("kex_derive_keys"); |
4f8c6159 | 478 | for (mode = 0; mode < MODE_MAX; mode++) { |
c422989b | 479 | current_keys[mode] = kex->newkeys[mode]; |
480 | kex->newkeys[mode] = NULL; | |
d1ac6175 | 481 | ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN); |
c422989b | 482 | current_keys[mode]->enc.iv = keys[ctos ? 0 : 1]; |
483 | current_keys[mode]->enc.key = keys[ctos ? 2 : 3]; | |
484 | current_keys[mode]->mac.key = keys[ctos ? 4 : 5]; | |
4f8c6159 | 485 | } |
4f8c6159 | 486 | } |
a5c9ffdb | 487 | |
d1ac6175 | 488 | Newkeys * |
489 | kex_get_newkeys(int mode) | |
490 | { | |
c422989b | 491 | Newkeys *ret; |
492 | ||
493 | ret = current_keys[mode]; | |
494 | current_keys[mode] = NULL; | |
495 | return ret; | |
d1ac6175 | 496 | } |
497 | ||
8bbf1fa6 | 498 | void |
499 | derive_ssh1_session_id(BIGNUM *host_modulus, BIGNUM *server_modulus, | |
500 | u_int8_t cookie[8], u_int8_t id[16]) | |
501 | { | |
502 | const EVP_MD *evp_md = EVP_md5(); | |
503 | EVP_MD_CTX md; | |
504 | u_int8_t nbuf[2048], obuf[EVP_MAX_MD_SIZE]; | |
505 | int len; | |
506 | ||
507 | EVP_DigestInit(&md, evp_md); | |
508 | ||
509 | len = BN_num_bytes(host_modulus); | |
2ceb8101 | 510 | if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) |
8bbf1fa6 | 511 | fatal("%s: bad host modulus (len %d)", __func__, len); |
512 | BN_bn2bin(host_modulus, nbuf); | |
513 | EVP_DigestUpdate(&md, nbuf, len); | |
514 | ||
515 | len = BN_num_bytes(server_modulus); | |
2ceb8101 | 516 | if (len < (512 / 8) || (u_int)len > sizeof(nbuf)) |
8bbf1fa6 | 517 | fatal("%s: bad server modulus (len %d)", __func__, len); |
518 | BN_bn2bin(server_modulus, nbuf); | |
519 | EVP_DigestUpdate(&md, nbuf, len); | |
520 | ||
521 | EVP_DigestUpdate(&md, cookie, 8); | |
522 | ||
59657003 | 523 | EVP_DigestFinal(&md, obuf, NULL); |
8bbf1fa6 | 524 | memcpy(id, obuf, 16); |
525 | ||
526 | memset(nbuf, 0, sizeof(nbuf)); | |
527 | memset(obuf, 0, sizeof(obuf)); | |
528 | memset(&md, 0, sizeof(md)); | |
529 | } | |
530 | ||
a5c9ffdb | 531 | #if defined(DEBUG_KEX) || defined(DEBUG_KEXDH) |
532 | void | |
533 | dump_digest(char *msg, u_char *digest, int len) | |
534 | { | |
2ceb8101 | 535 | u_int i; |
a5c9ffdb | 536 | |
537 | fprintf(stderr, "%s\n", msg); | |
6aacefa7 | 538 | for (i = 0; i< len; i++) { |
a5c9ffdb | 539 | fprintf(stderr, "%02x", digest[i]); |
540 | if (i%32 == 31) | |
541 | fprintf(stderr, "\n"); | |
542 | else if (i%8 == 7) | |
543 | fprintf(stderr, " "); | |
544 | } | |
545 | fprintf(stderr, "\n"); | |
546 | } | |
547 | #endif |