410c8acf |
1 | /* -*-c-*- |
2 | * |
7ed14135 |
3 | * $Id: keyexch.c,v 1.8 2003/07/13 11:19:49 mdw Exp $ |
410c8acf |
4 | * |
5 | * Key exchange protocol |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Trivial IP Encryption (TrIPE). |
13 | * |
14 | * TrIPE is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * TrIPE is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with TrIPE; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: keyexch.c,v $ |
7ed14135 |
32 | * Revision 1.8 2003/07/13 11:19:49 mdw |
33 | * Incopatible protocol fix! Include message type code under MAC tag to prevent |
34 | * cut-and-paste from key-exchange messages to general packet transport. |
35 | * |
2de0ad0f |
36 | * Revision 1.7 2003/05/17 11:01:28 mdw |
37 | * Handle flags on challenge timers correctly to prevent confusing the event |
38 | * list. |
39 | * |
9466fafa |
40 | * Revision 1.6 2003/04/06 10:26:35 mdw |
41 | * Report peer name on decrypt errors. |
42 | * |
5d418e24 |
43 | * Revision 1.5 2002/01/13 14:54:40 mdw |
44 | * Patch up zero-knowledge property by passing an encrypted log with a |
45 | * challenge, so that the prover can verify that the challenge is good. |
46 | * |
00e64b67 |
47 | * Revision 1.4 2001/06/22 19:40:36 mdw |
48 | * Support expiry of other peers' public keys. |
49 | * |
56814747 |
50 | * Revision 1.3 2001/06/19 22:07:09 mdw |
51 | * Cosmetic fixes. |
52 | * |
0617b6e7 |
53 | * Revision 1.2 2001/02/16 21:24:27 mdw |
54 | * Rewrite for new key exchange protocol. |
55 | * |
410c8acf |
56 | * Revision 1.1 2001/02/03 20:26:37 mdw |
57 | * Initial checkin. |
58 | * |
59 | */ |
60 | |
61 | /*----- Header files ------------------------------------------------------*/ |
62 | |
63 | #include "tripe.h" |
64 | |
65 | /*----- Tunable parameters ------------------------------------------------*/ |
66 | |
2de0ad0f |
67 | #define T_VALID MIN(2) /* Challenge validity period */ |
68 | #define T_RETRY SEC(10) /* Challenge retransmit interval */ |
410c8acf |
69 | |
0617b6e7 |
70 | #define ISVALID(kx, now) ((now) < (kx)->t_valid) |
71 | |
72 | /*----- Various utilities -------------------------------------------------*/ |
410c8acf |
73 | |
74 | /* --- @hashmp@ --- * |
75 | * |
0617b6e7 |
76 | * Arguments: @HASH_CTX *r@ = pointer to hash context |
410c8acf |
77 | * @mp *m@ = pointer to multiprecision integer |
78 | * |
79 | * Returns: --- |
80 | * |
81 | * Use: Adds the hash of a multiprecision integer to the context. |
0617b6e7 |
82 | * Corrupts @buf_t@. |
410c8acf |
83 | */ |
84 | |
0617b6e7 |
85 | static void hashmp(HASH_CTX *r, mp *m) |
410c8acf |
86 | { |
87 | buf b; |
0617b6e7 |
88 | buf_init(&b, buf_t, sizeof(buf_t)); |
410c8acf |
89 | buf_putmp(&b, m); |
90 | assert(BOK(&b)); |
0617b6e7 |
91 | HASH(r, BBASE(&b), BLEN(&b)); |
410c8acf |
92 | } |
93 | |
5d418e24 |
94 | /* --- @mpcrypt@ --- * |
95 | * |
96 | * Arguments: @mp *d@ = the destination integer |
97 | * @mp *x@ = the plaintext/ciphertext integer |
98 | * @size_t sz@ = the expected size of the plaintext |
99 | * @const octet *k@ = pointer to key material |
100 | * @size_t ksz@ = size of the key |
101 | * |
102 | * Returns: The encrypted/decrypted integer. |
103 | * |
104 | * Use: Encrypts (or decrypts) a multiprecision integer using another |
105 | * multiprecision integer as the key. This is a slightly grotty |
106 | * way to do this, but it's easier than the alternatives. |
107 | */ |
108 | |
109 | static mp *mpcrypt(mp *d, mp *x, size_t sz, const octet *k, size_t ksz) |
110 | { |
111 | MGF_CTX m; |
112 | |
113 | MGF_INIT(&m, k, ksz, 0); |
114 | mp_storeb(x, buf_t, sz); |
115 | MGF_CRYPT(&m, buf_t, buf_t, sz); |
116 | return (mp_loadb(d, buf_t, sz)); |
117 | } |
118 | |
410c8acf |
119 | /* --- @timer@ --- * |
120 | * |
121 | * Arguments: @struct timeval *tv@ = the current time |
122 | * @void *v@ = pointer to key exchange context |
123 | * |
124 | * Returns: --- |
125 | * |
126 | * Use: Acts when the key exchange timer goes off. |
127 | */ |
128 | |
129 | static void timer(struct timeval *tv, void *v) |
130 | { |
131 | keyexch *kx = v; |
132 | kx->f &= ~KXF_TIMER; |
133 | T( trace(T_KEYEXCH, "keyexch: timer has popped"); ) |
134 | kx_start(kx); |
135 | } |
136 | |
137 | /* --- @settimer@ --- * |
138 | * |
139 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
140 | * @time_t t@ = when to set the timer for |
141 | * |
142 | * Returns: --- |
143 | * |
144 | * Use: Sets the timer for the next key exchange attempt. |
145 | */ |
146 | |
147 | static void settimer(keyexch *kx, time_t t) |
148 | { |
149 | struct timeval tv; |
150 | if (kx->f & KXF_TIMER) |
151 | sel_rmtimer(&kx->t); |
152 | tv.tv_sec = t; |
153 | tv.tv_usec = 0; |
154 | sel_addtimer(&sel, &kx->t, &tv, timer, kx); |
155 | kx->f |= KXF_TIMER; |
156 | } |
157 | |
0617b6e7 |
158 | /*----- Challenge management ----------------------------------------------*/ |
159 | |
160 | /* --- Notes on challenge management --- * |
410c8acf |
161 | * |
0617b6e7 |
162 | * We may get multiple different replies to our key exchange; some will be |
163 | * correct, some inserted by attackers. Up until @KX_THRESH@, all challenges |
164 | * received will be added to the table and given a full response. After |
165 | * @KX_THRESH@ distinct challenges are received, we return only a `cookie': |
166 | * our existing challenge, followed by a hash of the sender's challenge. We |
167 | * do %%\emph{not}%% give a bare challenge a reply slot at this stage. All |
168 | * properly-formed cookies are assigned a table slot: if none is spare, a |
169 | * used slot is randomly selected and destroyed. A cookie always receives a |
170 | * full reply. |
171 | */ |
172 | |
173 | /* --- @kxc_destroy@ --- * |
174 | * |
175 | * Arguments: @kxchal *kxc@ = pointer to the challenge block |
410c8acf |
176 | * |
177 | * Returns: --- |
178 | * |
0617b6e7 |
179 | * Use: Disposes of a challenge block. |
410c8acf |
180 | */ |
181 | |
0617b6e7 |
182 | static void kxc_destroy(kxchal *kxc) |
410c8acf |
183 | { |
0617b6e7 |
184 | if (kxc->f & KXF_TIMER) |
185 | sel_rmtimer(&kxc->t); |
186 | mp_drop(kxc->c); |
187 | mp_drop(kxc->r); |
5d418e24 |
188 | mp_drop(kxc->ck); |
0617b6e7 |
189 | ks_drop(kxc->ks); |
190 | DESTROY(kxc); |
191 | } |
410c8acf |
192 | |
0617b6e7 |
193 | /* --- @kxc_stoptimer@ --- * |
194 | * |
195 | * Arguments: @kxchal *kxc@ = pointer to the challenge block |
196 | * |
197 | * Returns: --- |
198 | * |
199 | * Use: Stops the challenge's retry timer from sending messages. |
200 | * Useful when the state machine is in the endgame of the |
201 | * exchange. |
202 | */ |
410c8acf |
203 | |
0617b6e7 |
204 | static void kxc_stoptimer(kxchal *kxc) |
205 | { |
206 | if (kxc->f & KXF_TIMER) |
207 | sel_rmtimer(&kxc->t); |
2de0ad0f |
208 | kxc->f &= ~KXF_TIMER; |
0617b6e7 |
209 | } |
410c8acf |
210 | |
0617b6e7 |
211 | /* --- @kxc_new@ --- * |
212 | * |
213 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
0617b6e7 |
214 | * |
215 | * Returns: A pointer to the challenge block. |
216 | * |
217 | * Use: Returns a pointer to a new challenge block to fill in. |
218 | */ |
410c8acf |
219 | |
0617b6e7 |
220 | static kxchal *kxc_new(keyexch *kx) |
221 | { |
222 | kxchal *kxc; |
223 | unsigned i; |
224 | |
225 | /* --- If we're over reply threshold, discard one at random --- */ |
226 | |
227 | if (kx->nr < KX_NCHAL) |
228 | i = kx->nr++; |
229 | else { |
230 | i = rand_global.ops->range(&rand_global, KX_NCHAL); |
231 | kxc_destroy(kx->r[i]); |
410c8acf |
232 | } |
233 | |
0617b6e7 |
234 | /* --- Fill in the new structure --- */ |
410c8acf |
235 | |
0617b6e7 |
236 | kxc = CREATE(kxchal); |
237 | kxc->c = 0; |
238 | kxc->r = 0; |
5d418e24 |
239 | kxc->ck = 0; |
0617b6e7 |
240 | kxc->ks = 0; |
241 | kxc->kx = kx; |
242 | kxc->f = 0; |
243 | kx->r[i] = kxc; |
244 | return (kxc); |
245 | } |
410c8acf |
246 | |
0617b6e7 |
247 | /* --- @kxc_bychal@ --- * |
248 | * |
249 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
250 | * @mp *c@ = challenge from remote host |
251 | * |
252 | * Returns: Pointer to the challenge block, or null. |
253 | * |
254 | * Use: Finds a challenge block, given its challenge. |
255 | */ |
256 | |
257 | static kxchal *kxc_bychal(keyexch *kx, mp *c) |
258 | { |
259 | unsigned i; |
260 | |
261 | for (i = 0; i < kx->nr; i++) { |
262 | if (MP_EQ(c, kx->r[i]->c)) |
263 | return (kx->r[i]); |
264 | } |
265 | return (0); |
266 | } |
267 | |
268 | /* --- @kxc_byhc@ --- * |
269 | * |
270 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
271 | * @const octet *hc@ = challenge hash from remote host |
272 | * |
273 | * Returns: Pointer to the challenge block, or null. |
274 | * |
275 | * Use: Finds a challenge block, given a hash of its challenge. |
276 | */ |
410c8acf |
277 | |
0617b6e7 |
278 | static kxchal *kxc_byhc(keyexch *kx, const octet *hc) |
279 | { |
280 | unsigned i; |
281 | |
282 | for (i = 0; i < kx->nr; i++) { |
283 | if (memcmp(hc, kx->r[i]->hc, HASHSZ) == 0) |
284 | return (kx->r[i]); |
410c8acf |
285 | } |
0617b6e7 |
286 | return (0); |
287 | } |
288 | |
289 | /* --- @kxc_answer@ --- * |
290 | * |
291 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
292 | * @kxchal *kxc@ = pointer to challenge block |
293 | * |
294 | * Returns: --- |
295 | * |
296 | * Use: Sends a reply to the remote host, according to the data in |
297 | * this challenge block. |
298 | */ |
299 | |
300 | static void kxc_answer(keyexch *kx, kxchal *kxc); |
301 | |
302 | static void kxc_timer(struct timeval *tv, void *v) |
303 | { |
304 | kxchal *kxc = v; |
305 | kxc->f &= ~KXF_TIMER; |
306 | kxc_answer(kxc->kx, kxc); |
307 | } |
308 | |
309 | static void kxc_answer(keyexch *kx, kxchal *kxc) |
310 | { |
311 | stats *st = p_stats(kx->p); |
312 | buf *b = p_txstart(kx->p, MSG_KEYEXCH | (kxc->r ? KX_REPLY : KX_CHAL)); |
313 | struct timeval tv; |
314 | buf bb; |
315 | |
316 | /* --- Build the reply packet --- */ |
317 | |
318 | if (!kxc->r) |
319 | buf_putmp(b, kx->c); |
320 | else |
321 | buf_put(b, kx->hc, HASHSZ); |
322 | buf_put(b, kxc->hc, HASHSZ); |
5d418e24 |
323 | buf_putmp(b, kxc->ck); |
0617b6e7 |
324 | |
325 | /* --- Maybe send an actual reply, if we have one --- */ |
410c8acf |
326 | |
0617b6e7 |
327 | if (!kxc->r) { |
328 | T( trace(T_KEYEXCH, "keyexch: resending challenge to `%s'", |
329 | p_name(kx->p)); ) |
330 | } else { |
331 | T( trace(T_KEYEXCH, "keyexch: sending reply to `%s'", p_name(kx->p)); ) |
332 | buf_init(&bb, buf_i, sizeof(buf_i)); |
333 | buf_putmp(&bb, kxc->r); |
334 | buf_flip(&bb); |
7ed14135 |
335 | ks_encrypt(kxc->ks, MSG_KEYEXCH | KX_REPLY, &bb, b); |
0617b6e7 |
336 | } |
337 | |
338 | /* --- Update the statistics --- */ |
339 | |
340 | if (BOK(b)) { |
341 | st->n_kxout++; |
342 | st->sz_kxout += BLEN(b); |
343 | p_txend(kx->p); |
344 | } |
345 | |
346 | /* --- Schedule another resend --- */ |
347 | |
348 | if (kxc->f & KXF_TIMER) |
349 | sel_rmtimer(&kxc->t); |
350 | gettimeofday(&tv, 0); |
351 | tv.tv_sec += T_RETRY; |
352 | sel_addtimer(&sel, &kxc->t, &tv, kxc_timer, kxc); |
353 | kxc->f |= KXF_TIMER; |
354 | } |
355 | |
356 | /*----- Individual message handlers ---------------------------------------*/ |
357 | |
358 | /* --- @getreply@ --- * |
359 | * |
360 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
361 | * @mp *c@ = a challenge |
5d418e24 |
362 | * @mp *ck@ = the supplied expected-reply check value |
0617b6e7 |
363 | * |
364 | * Returns: A pointer to the reply, or null if the reply-hash was wrong. |
365 | * |
366 | * Use: Computes replies to challenges. |
367 | */ |
368 | |
5d418e24 |
369 | static mp *getreply(keyexch *kx, mp *c, mp *ck) |
0617b6e7 |
370 | { |
371 | mp *r = mpmont_exp(&mg, MP_NEW, c, kpriv.x); |
5d418e24 |
372 | mp *a; |
0617b6e7 |
373 | HASH_CTX h; |
5d418e24 |
374 | octet buf[HASHSZ]; |
375 | int ok; |
0617b6e7 |
376 | |
377 | HASH_INIT(&h); |
378 | HASH_STRING(&h, "tripe-expected-reply"); |
379 | hashmp(&h, c); |
380 | hashmp(&h, kx->c); |
381 | hashmp(&h, r); |
382 | HASH_DONE(&h, buf); |
5d418e24 |
383 | |
384 | a = mpcrypt(MP_NEW, ck, mp_octets(kpriv.dp.q), buf, sizeof(buf)); |
0617b6e7 |
385 | IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, { |
386 | trace(T_CRYPTO, "crypto: computed reply = %s", mpstr(r)); |
387 | trace_block(T_CRYPTO, "crypto: computed reply hash", buf, HASHSZ); |
5d418e24 |
388 | trace(T_CRYPTO, "crypto: recovered log = %s", mpstr(a)); |
0617b6e7 |
389 | })) |
5d418e24 |
390 | a = mpmont_exp(&mg, a, kpriv.dp.g, a); |
391 | ok = mp_eq(a, c); |
392 | if (!ok) { |
393 | a_warn("invalid expected-reply check from `%s'", p_name(kx->p)); |
394 | IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, { |
395 | trace(T_CRYPTO, "crypto: computed challenge = %s", mpstr(a)); |
396 | })) |
0617b6e7 |
397 | mp_drop(r); |
0617b6e7 |
398 | } |
5d418e24 |
399 | mp_drop(a); |
400 | return (ok ? r : 0); |
0617b6e7 |
401 | } |
402 | |
403 | /* --- @dochallenge@ --- * |
404 | * |
405 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
406 | * @unsigned msg@ = message code for the packet |
407 | * @buf *b@ = buffer containing the packet |
408 | * |
409 | * Returns: Zero if OK, nonzero if the packet was rejected. |
410 | * |
411 | * Use: Processes a packet containing a challenge. |
412 | */ |
413 | |
414 | static int dochallenge(keyexch *kx, unsigned msg, buf *b) |
415 | { |
5d418e24 |
416 | mp *c = 0, *ck = 0; |
417 | const octet *hc = 0; |
0617b6e7 |
418 | kxchal *kxc; |
419 | HASH_CTX h; |
5d418e24 |
420 | octet buf[HASHSZ]; |
0617b6e7 |
421 | |
422 | /* --- Ensure that we're in a sensible state --- */ |
423 | |
424 | if (kx->s != KXS_CHAL) { |
425 | a_warn("unexpected challenge from `%s'", p_name(kx->p)); |
426 | goto bad; |
427 | } |
428 | |
429 | /* --- Unpack the packet --- */ |
430 | |
431 | if ((c = buf_getmp(b)) == 0 || |
432 | (msg >= KX_COOKIE && (hc = buf_get(b, HASHSZ)) == 0) || |
5d418e24 |
433 | (msg >= KX_CHAL && (ck = buf_getmp(b)) == 0) || |
0617b6e7 |
434 | BLEFT(b)) { |
435 | a_warn("malformed packet from `%s'", p_name(kx->p)); |
436 | goto bad; |
437 | } |
438 | |
439 | IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, { |
440 | trace(T_CRYPTO, "crypto: challenge = %s", mpstr(c)); |
441 | if (hc) trace_block(T_CRYPTO, "crypto: cookie", hc, HASHSZ); |
5d418e24 |
442 | if (ck) trace(T_CRYPTO, "crypto: check value = %s", mpstr(ck)); |
0617b6e7 |
443 | })) |
444 | |
445 | /* --- First, handle a bare challenge --- * |
446 | * |
447 | * If the table is heavily loaded, just emit a cookie and return. |
448 | */ |
449 | |
450 | if (!hc && kx->nr >= KX_THRESH) { |
451 | T( trace(T_KEYEXCH, "keyexch: too many challenges -- sending cookie"); ) |
452 | b = p_txstart(kx->p, MSG_KEYEXCH | KX_COOKIE); |
453 | buf_putmp(b, kx->c); |
454 | HASH_INIT(&h); |
455 | HASH_STRING(&h, "tripe-cookie"); |
456 | hashmp(&h, c); |
457 | HASH_DONE(&h, buf_get(b, HASHSZ)); |
458 | p_txend(kx->p); |
459 | goto tidy; |
460 | } |
461 | |
462 | /* --- Discard a packet with an invalid cookie --- */ |
463 | |
464 | if (hc && memcmp(hc, kx->hc, HASHSZ) != 0) { |
465 | a_warn("incorrect cookie from `%s'", p_name(kx->p)); |
466 | goto bad; |
467 | } |
468 | |
469 | /* --- Find a challenge block for this packet --- * |
410c8acf |
470 | * |
0617b6e7 |
471 | * If there isn't one already, create a new one. |
410c8acf |
472 | */ |
473 | |
0617b6e7 |
474 | if ((kxc = kxc_bychal(kx, c)) == 0) { |
475 | size_t x, y, z; |
476 | mp *r; |
477 | |
478 | /* --- Be careful here --- * |
479 | * |
480 | * If this is a full challenge, and it's the first time I've seen it, I |
481 | * want to be able to throw it away before committing a table entry to |
482 | * it. |
483 | */ |
484 | |
5d418e24 |
485 | if (!ck) |
0617b6e7 |
486 | kxc = kxc_new(kx); |
487 | else { |
5d418e24 |
488 | if ((r = getreply(kx, c, ck)) == 0) |
0617b6e7 |
489 | goto bad; |
490 | kxc = kxc_new(kx); |
491 | kxc->r = r; |
410c8acf |
492 | } |
0617b6e7 |
493 | kxc->c = mp_copy(c); |
494 | |
495 | /* --- Work out the cookie for this challenge --- */ |
496 | |
497 | HASH_INIT(&h); |
498 | HASH_STRING(&h, "tripe-cookie"); |
499 | hashmp(&h, kxc->c); |
500 | HASH_DONE(&h, kxc->hc); |
501 | |
502 | /* --- Compute the expected-reply hash --- */ |
503 | |
504 | HASH_INIT(&h); |
505 | HASH_STRING(&h, "tripe-expected-reply"); |
506 | hashmp(&h, kx->c); |
507 | hashmp(&h, kxc->c); |
508 | hashmp(&h, kx->rx); |
5d418e24 |
509 | HASH_DONE(&h, buf); |
510 | kxc->ck = mpcrypt(MP_NEW, kx->alpha, mp_octets(kpriv.dp.q), |
511 | buf, sizeof(buf)); |
0617b6e7 |
512 | |
513 | /* --- Work out the shared key --- */ |
514 | |
5d418e24 |
515 | trace(T_CRYPTO, "debug: c = %s", mpstr(c)); |
516 | trace(T_CRYPTO, "debug: alpha = %s", mpstr(kx->alpha)); |
0617b6e7 |
517 | r = mpmont_exp(&mg, MP_NEW, c, kx->alpha); |
5d418e24 |
518 | trace(T_CRYPTO, "debug: r = %s", mpstr(r)); |
0617b6e7 |
519 | |
520 | /* --- Compute the switch messages --- */ |
521 | |
522 | HASH_INIT(&h); HASH_STRING(&h, "tripe-switch-request"); |
523 | hashmp(&h, kx->c); hashmp(&h, kxc->c); |
524 | HASH_DONE(&h, kxc->hswrq_out); |
525 | HASH_INIT(&h); HASH_STRING(&h, "tripe-switch-confirm"); |
526 | hashmp(&h, kx->c); hashmp(&h, kxc->c); |
527 | HASH_DONE(&h, kxc->hswok_out); |
528 | |
529 | HASH_INIT(&h); HASH_STRING(&h, "tripe-switch-request"); |
530 | hashmp(&h, kxc->c); hashmp(&h, kx->c); |
531 | HASH_DONE(&h, kxc->hswrq_in); |
532 | HASH_INIT(&h); HASH_STRING(&h, "tripe-switch-confirm"); |
533 | hashmp(&h, kxc->c); hashmp(&h, kx->c); |
534 | HASH_DONE(&h, kxc->hswok_in); |
535 | |
536 | IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, { |
537 | trace_block(T_CRYPTO, "crypto: computed cookie", kxc->hc, HASHSZ); |
5d418e24 |
538 | trace_block(T_CRYPTO, "crypto: expected-reply hash", |
539 | buf, HASHSZ); |
540 | trace(T_CRYPTO, "crypto: my reply check = %s", mpstr(kxc->ck)); |
0617b6e7 |
541 | trace(T_CRYPTO, "crypto: shared secret = %s", mpstr(r)); |
542 | trace_block(T_CRYPTO, "crypto: outbound switch request", |
543 | kxc->hswrq_out, HASHSZ); |
544 | trace_block(T_CRYPTO, "crypto: outbound switch confirm", |
545 | kxc->hswok_out, HASHSZ); |
546 | trace_block(T_CRYPTO, "crypto: inbound switch request", |
547 | kxc->hswrq_in, HASHSZ); |
548 | trace_block(T_CRYPTO, "crypto: inbound switch confirm", |
549 | kxc->hswok_in, HASHSZ); |
550 | })) |
551 | |
552 | /* --- Create a new symmetric keyset --- */ |
553 | |
554 | buf_init(b, buf_o, sizeof(buf_o)); |
555 | buf_putmp(b, kx->c); x = BLEN(b); |
556 | buf_putmp(b, kxc->c); y = BLEN(b); |
557 | buf_putmp(b, r); z = BLEN(b); |
558 | assert(BOK(b)); |
559 | |
9466fafa |
560 | kxc->ks = ks_gen(BBASE(b), x, y, z, kx->p); |
0617b6e7 |
561 | mp_drop(r); |
410c8acf |
562 | } |
563 | |
0617b6e7 |
564 | /* --- Answer the challenge if we need to --- */ |
410c8acf |
565 | |
5d418e24 |
566 | if (ck && !kxc->r) { |
0617b6e7 |
567 | mp *r; |
5d418e24 |
568 | if ((r = getreply(kx, c, ck)) == 0) |
0617b6e7 |
569 | goto bad; |
570 | kxc->r = r; |
410c8acf |
571 | } |
0617b6e7 |
572 | |
573 | kxc_answer(kx, kxc); |
574 | |
575 | /* --- Tidy up and go home --- */ |
576 | |
577 | tidy: |
578 | mp_drop(c); |
5d418e24 |
579 | mp_drop(ck); |
0617b6e7 |
580 | return (0); |
581 | |
582 | bad: |
583 | mp_drop(c); |
5d418e24 |
584 | mp_drop(ck); |
0617b6e7 |
585 | return (-1); |
410c8acf |
586 | } |
587 | |
0617b6e7 |
588 | /* --- @resend@ --- * |
410c8acf |
589 | * |
590 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
410c8acf |
591 | * |
592 | * Returns: --- |
593 | * |
0617b6e7 |
594 | * Use: Sends the next message for a key exchange. |
410c8acf |
595 | */ |
596 | |
0617b6e7 |
597 | static void resend(keyexch *kx) |
410c8acf |
598 | { |
0617b6e7 |
599 | kxchal *kxc; |
600 | buf bb; |
601 | stats *st = p_stats(kx->p); |
410c8acf |
602 | buf *b; |
603 | |
0617b6e7 |
604 | switch (kx->s) { |
605 | case KXS_CHAL: |
00e64b67 |
606 | T( trace(T_KEYEXCH, "keyexch: sending prechallenge to `%s'", |
607 | p_name(kx->p)); ) |
0617b6e7 |
608 | b = p_txstart(kx->p, MSG_KEYEXCH | KX_PRECHAL); |
609 | buf_putmp(b, kx->c); |
610 | break; |
611 | case KXS_COMMIT: |
00e64b67 |
612 | T( trace(T_KEYEXCH, "keyexch: sending switch request to `%s'", |
613 | p_name(kx->p)); ) |
0617b6e7 |
614 | kxc = kx->r[0]; |
615 | b = p_txstart(kx->p, MSG_KEYEXCH | KX_SWITCH); |
616 | buf_put(b, kx->hc, HASHSZ); |
617 | buf_put(b, kxc->hc, HASHSZ); |
618 | buf_init(&bb, buf_i, sizeof(buf_i)); |
619 | buf_putmp(&bb, kxc->r); |
620 | buf_put(&bb, kxc->hswrq_out, HASHSZ); |
621 | buf_flip(&bb); |
7ed14135 |
622 | ks_encrypt(kxc->ks, MSG_KEYEXCH | KX_SWITCH, &bb, b); |
0617b6e7 |
623 | break; |
624 | case KXS_SWITCH: |
00e64b67 |
625 | T( trace(T_KEYEXCH, "keyexch: sending switch confirmation to `%s'", |
0617b6e7 |
626 | p_name(kx->p)); ) |
627 | kxc = kx->r[0]; |
628 | b = p_txstart(kx->p, MSG_KEYEXCH | KX_SWITCHOK); |
629 | buf_init(&bb, buf_i, sizeof(buf_i)); |
630 | buf_put(&bb, kxc->hswok_out, HASHSZ); |
631 | buf_flip(&bb); |
7ed14135 |
632 | ks_encrypt(kxc->ks, MSG_KEYEXCH | KX_SWITCHOK, &bb, b); |
0617b6e7 |
633 | break; |
634 | default: |
635 | abort(); |
410c8acf |
636 | } |
0617b6e7 |
637 | |
638 | if (BOK(b)) { |
639 | st->n_kxout++; |
640 | st->sz_kxout += BLEN(b); |
641 | p_txend(kx->p); |
642 | } |
643 | |
644 | if (kx->s < KXS_SWITCH) |
645 | settimer(kx, time(0) + T_RETRY); |
410c8acf |
646 | } |
647 | |
0617b6e7 |
648 | /* --- @matchreply@ --- * |
649 | * |
650 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
7ed14135 |
651 | * @unsigned ty@ = type of incoming message |
0617b6e7 |
652 | * @const octet *hc_in@ = a hash of his challenge |
653 | * @const octet *hc_out@ = a hash of my challenge (cookie) |
5d418e24 |
654 | * @mp *ck@ = his expected-reply hash (optional) |
0617b6e7 |
655 | * @buf *b@ = encrypted remainder of the packet |
656 | * |
657 | * Returns: A pointer to the challenge block if OK, or null on failure. |
658 | * |
659 | * Use: Checks a reply or switch packet, ensuring that its contents |
660 | * are sensible and correct. If they are, @*b@ is set to point |
661 | * to the remainder of the encrypted data, and the correct |
662 | * challenge is returned. |
663 | */ |
664 | |
7ed14135 |
665 | static kxchal *matchreply(keyexch *kx, unsigned ty, const octet *hc_in, |
5d418e24 |
666 | const octet *hc_out, mp *ck, buf *b) |
410c8acf |
667 | { |
0617b6e7 |
668 | kxchal *kxc; |
669 | buf bb; |
670 | mp *r = 0; |
671 | |
672 | /* --- Check the plaintext portions of the data --- */ |
673 | |
674 | IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, { |
675 | trace_block(T_CRYPTO, "crypto: challenge", hc_in, HASHSZ); |
676 | trace_block(T_CRYPTO, "crypto: cookie", hc_out, HASHSZ); |
5d418e24 |
677 | if (ck) trace(T_CRYPTO, "crypto: check value = %s", mpstr(ck)); |
0617b6e7 |
678 | })) |
679 | if (memcmp(hc_out, kx->hc, HASHSZ) != 0) { |
680 | a_warn("incorrect cookie from `%s'", p_name(kx->p)); |
681 | goto bad; |
682 | } |
683 | if ((kxc = kxc_byhc(kx, hc_in)) == 0) { |
684 | a_warn("received reply for unknown challenge from `%s'", p_name(kx->p)); |
685 | goto bad; |
686 | } |
410c8acf |
687 | |
0617b6e7 |
688 | /* --- Maybe compute a reply for the challenge --- */ |
689 | |
690 | if (!kxc->r) { |
5d418e24 |
691 | if (!ck) { |
0617b6e7 |
692 | a_warn("unexpected switch request from `%s'", p_name(kx->p)); |
693 | goto bad; |
694 | } |
5d418e24 |
695 | if ((r = getreply(kx, kxc->c, ck)) == 0) |
0617b6e7 |
696 | goto bad; |
697 | kxc->r = r; |
698 | r = 0; |
699 | } |
700 | |
701 | /* --- Decrypt the rest of the packet --- */ |
702 | |
703 | buf_init(&bb, buf_o, sizeof(buf_o)); |
7ed14135 |
704 | if (ks_decrypt(kxc->ks, ty, b, &bb)) { |
0617b6e7 |
705 | a_warn("failed to decrypt reply from `%s'", p_name(kx->p)); |
706 | goto bad; |
410c8acf |
707 | } |
0617b6e7 |
708 | buf_init(b, BBASE(&bb), BLEN(&bb)); |
709 | if ((r = buf_getmp(b)) == 0) { |
710 | a_warn("invalid reply packet from `%s'", p_name(kx->p)); |
711 | goto bad; |
712 | } |
713 | IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, { |
714 | trace(T_CRYPTO, "crypto: reply = %s", mpstr(r)); |
715 | })) |
716 | if (!mp_eq(r, kx->rx)) { |
717 | a_warn("incorrect reply from `%s'", p_name(kx->p)); |
718 | goto bad; |
719 | } |
720 | |
721 | /* --- Done --- */ |
722 | |
723 | mp_drop(r); |
724 | return (kxc); |
725 | |
726 | bad: |
727 | mp_drop(r); |
728 | return (0); |
410c8acf |
729 | } |
730 | |
0617b6e7 |
731 | /* --- @commit@ --- * |
410c8acf |
732 | * |
733 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
0617b6e7 |
734 | * @kxchal *kxc@ = pointer to challenge to commit to |
410c8acf |
735 | * |
736 | * Returns: --- |
737 | * |
0617b6e7 |
738 | * Use: Commits to a particular challenge as being the `right' one, |
739 | * since a reply has arrived for it. |
410c8acf |
740 | */ |
741 | |
0617b6e7 |
742 | static void commit(keyexch *kx, kxchal *kxc) |
410c8acf |
743 | { |
0617b6e7 |
744 | unsigned i; |
410c8acf |
745 | |
0617b6e7 |
746 | for (i = 0; i < kx->nr; i++) { |
747 | if (kx->r[i] != kxc) |
748 | kxc_destroy(kx->r[i]); |
749 | } |
750 | kx->r[0] = kxc; |
751 | kx->nr = 1; |
752 | kxc_stoptimer(kxc); |
753 | ksl_link(kx->ks, kxc->ks); |
410c8acf |
754 | } |
755 | |
0617b6e7 |
756 | /* --- @doreply@ --- * |
410c8acf |
757 | * |
758 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
0617b6e7 |
759 | * @buf *b@ = buffer containing packet |
410c8acf |
760 | * |
0617b6e7 |
761 | * Returns: Zero if OK, nonzero if the packet was rejected. |
410c8acf |
762 | * |
0617b6e7 |
763 | * Use: Handles a reply packet. This doesn't handle the various |
764 | * switch packets: they're rather too different. |
410c8acf |
765 | */ |
766 | |
0617b6e7 |
767 | static int doreply(keyexch *kx, buf *b) |
410c8acf |
768 | { |
5d418e24 |
769 | const octet *hc_in, *hc_out; |
770 | mp *ck = 0; |
0617b6e7 |
771 | kxchal *kxc; |
772 | |
773 | if (kx->s != KXS_CHAL && kx->s != KXS_COMMIT) { |
774 | a_warn("unexpected reply from `%s'", p_name(kx->p)); |
775 | goto bad; |
776 | } |
777 | if ((hc_in = buf_get(b, HASHSZ)) == 0 || |
778 | (hc_out = buf_get(b, HASHSZ)) == 0 || |
5d418e24 |
779 | (ck = buf_getmp(b)) == 0) { |
0617b6e7 |
780 | a_warn("invalid reply packet from `%s'", p_name(kx->p)); |
781 | goto bad; |
782 | } |
7ed14135 |
783 | if ((kxc = matchreply(kx, MSG_KEYEXCH | KX_REPLY, |
784 | hc_in, hc_out, ck, b)) == 0) |
0617b6e7 |
785 | goto bad; |
786 | if (BLEFT(b)) { |
787 | a_warn("invalid reply packet from `%s'", p_name(kx->p)); |
788 | goto bad; |
789 | } |
790 | if (kx->s == KXS_CHAL) { |
791 | commit(kx, kxc); |
792 | kx->s = KXS_COMMIT; |
793 | } |
794 | resend(kx); |
795 | return (0); |
796 | |
797 | bad: |
5d418e24 |
798 | mp_drop(ck); |
0617b6e7 |
799 | return (-1); |
410c8acf |
800 | } |
801 | |
0617b6e7 |
802 | /* --- @doswitch@ --- * |
410c8acf |
803 | * |
0617b6e7 |
804 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
805 | * @buf *b@ = pointer to buffer containing packet |
410c8acf |
806 | * |
0617b6e7 |
807 | * Returns: Zero if OK, nonzero if the packet was rejected. |
410c8acf |
808 | * |
0617b6e7 |
809 | * Use: Handles a reply with a switch request bolted onto it. |
410c8acf |
810 | */ |
811 | |
0617b6e7 |
812 | static int doswitch(keyexch *kx, buf *b) |
410c8acf |
813 | { |
0617b6e7 |
814 | const octet *hc_in, *hc_out, *hswrq; |
815 | kxchal *kxc; |
410c8acf |
816 | |
0617b6e7 |
817 | if ((hc_in = buf_get(b, HASHSZ)) == 0 || |
818 | (hc_out = buf_get(b, HASHSZ)) == 0) { |
819 | a_warn("invalid switch request from `%s'", p_name(kx->p)); |
820 | goto bad; |
410c8acf |
821 | } |
7ed14135 |
822 | if ((kxc = matchreply(kx, MSG_KEYEXCH | KX_SWITCH, |
823 | hc_in, hc_out, 0, b)) == 0) |
0617b6e7 |
824 | goto bad; |
825 | if ((hswrq = buf_get(b, HASHSZ)) == 0 || BLEFT(b)) { |
826 | a_warn("invalid switch request from `%s'", p_name(kx->p)); |
827 | goto bad; |
828 | } |
829 | IF_TRACING(T_KEYEXCH, { |
830 | trace_block(T_CRYPTO, "crypto: switch request hash", hswrq, HASHSZ); |
831 | }) |
832 | if (memcmp(hswrq, kxc->hswrq_in, HASHSZ) != 0) { |
833 | a_warn("incorrect switch request hash from `%s'", p_name(kx->p)); |
834 | goto bad; |
835 | } |
836 | switch (kx->s) { |
837 | case KXS_CHAL: |
838 | commit(kx, kxc); |
839 | case KXS_COMMIT: |
840 | ks_activate(kxc->ks); |
841 | settimer(kx, ks_tregen(kxc->ks)); |
842 | kx->s = KXS_SWITCH; |
843 | break; |
844 | } |
845 | resend(kx); |
846 | return (0); |
847 | |
848 | bad: |
849 | return (-1); |
410c8acf |
850 | } |
851 | |
0617b6e7 |
852 | /* --- @doswitchok@ --- * |
853 | * |
854 | * Arguments: @keyexch *kx@ = pointer to key exchange block |
855 | * @buf *b@ = pointer to buffer containing packet |
856 | * |
857 | * Returns: Zero if OK, nonzero if the packet was rejected. |
858 | * |
859 | * Use: Handles a reply with a switch request bolted onto it. |
860 | */ |
861 | |
862 | static int doswitchok(keyexch *kx, buf *b) |
410c8acf |
863 | { |
0617b6e7 |
864 | const octet *hswok; |
865 | kxchal *kxc; |
866 | buf bb; |
410c8acf |
867 | |
0617b6e7 |
868 | if (kx->s < KXS_COMMIT) { |
869 | a_warn("unexpected switch confirmation from `%s'", p_name(kx->p)); |
870 | goto bad; |
410c8acf |
871 | } |
0617b6e7 |
872 | kxc = kx->r[0]; |
873 | buf_init(&bb, buf_o, sizeof(buf_o)); |
7ed14135 |
874 | if (ks_decrypt(kxc->ks, MSG_KEYEXCH | KX_SWITCHOK, b, &bb)) { |
0617b6e7 |
875 | a_warn("failed to decrypt switch confirmation from `%s'", p_name(kx->p)); |
876 | goto bad; |
877 | } |
878 | buf_init(b, BBASE(&bb), BLEN(&bb)); |
879 | if ((hswok = buf_get(b, HASHSZ)) == 0 || BLEFT(b)) { |
880 | a_warn("invalid switch confirmation from `%s'", p_name(kx->p)); |
881 | goto bad; |
882 | } |
883 | IF_TRACING(T_KEYEXCH, { |
884 | trace_block(T_CRYPTO, "crypto: switch confirmation hash", hswok, HASHSZ); |
885 | }) |
886 | if (memcmp(hswok, kxc->hswok_in, HASHSZ) != 0) { |
887 | a_warn("incorrect switch confirmation hash from `%s'", p_name(kx->p)); |
888 | goto bad; |
889 | } |
890 | if (kx->s < KXS_SWITCH) { |
891 | ks_activate(kxc->ks); |
892 | settimer(kx, ks_tregen(kxc->ks)); |
893 | kx->s = KXS_SWITCH; |
894 | } |
895 | return (0); |
896 | |
897 | bad: |
898 | return (-1); |
899 | } |
900 | |
901 | /*----- Main code ---------------------------------------------------------*/ |
902 | |
903 | /* --- @stop@ --- * |
904 | * |
905 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
906 | * |
907 | * Returns: --- |
908 | * |
909 | * Use: Stops a key exchange dead in its tracks. Throws away all of |
910 | * the context information. The context is left in an |
911 | * inconsistent state. The only functions which understand this |
912 | * state are @kx_free@ and @kx_init@ (which cause it internally |
913 | * it), and @start@ (which expects it to be the prevailing |
914 | * state). |
915 | */ |
916 | |
917 | static void stop(keyexch *kx) |
918 | { |
919 | unsigned i; |
920 | |
00e64b67 |
921 | if (kx->f & KXF_DEAD) |
922 | return; |
923 | |
0617b6e7 |
924 | if (kx->f & KXF_TIMER) |
925 | sel_rmtimer(&kx->t); |
926 | for (i = 0; i < kx->nr; i++) |
927 | kxc_destroy(kx->r[i]); |
928 | mp_drop(kx->alpha); |
929 | mp_drop(kx->c); |
930 | mp_drop(kx->rx); |
00e64b67 |
931 | kx->t_valid = 0; |
932 | kx->f |= KXF_DEAD; |
933 | kx->f &= ~KXF_TIMER; |
0617b6e7 |
934 | } |
935 | |
936 | /* --- @start@ --- * |
937 | * |
938 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
939 | * @time_t now@ = the current time |
940 | * |
941 | * Returns: --- |
942 | * |
943 | * Use: Starts a new key exchange with the peer. The context must be |
944 | * in the bizarre state left by @stop@ or @kx_init@. |
945 | */ |
946 | |
947 | static void start(keyexch *kx, time_t now) |
948 | { |
949 | HASH_CTX h; |
950 | |
00e64b67 |
951 | assert(kx->f & KXF_DEAD); |
952 | |
953 | kx->f &= ~KXF_DEAD; |
0617b6e7 |
954 | kx->nr = 0; |
0617b6e7 |
955 | kx->alpha = mprand_range(MP_NEW, kpriv.dp.q, &rand_global, 0); |
956 | kx->c = mpmont_exp(&mg, MP_NEW, kpriv.dp.g, kx->alpha); |
957 | kx->rx = mpmont_exp(&mg, MP_NEW, kx->kpub.y, kx->alpha); |
958 | kx->s = KXS_CHAL; |
959 | kx->t_valid = now + T_VALID; |
960 | |
961 | HASH_INIT(&h); |
962 | HASH_STRING(&h, "tripe-cookie"); |
963 | hashmp(&h, kx->c); |
964 | HASH_DONE(&h, kx->hc); |
965 | |
966 | IF_TRACING(T_KEYEXCH, { |
967 | trace(T_KEYEXCH, "keyexch: creating new challenge"); |
968 | IF_TRACING(T_CRYPTO, { |
969 | trace(T_CRYPTO, "crypto: secret = %s", mpstr(kx->alpha)); |
970 | trace(T_CRYPTO, "crypto: challenge = %s", mpstr(kx->c)); |
971 | trace(T_CRYPTO, "crypto: expected response = %s", mpstr(kx->rx)); |
972 | trace_block(T_CRYPTO, "crypto: challenge cookie", kx->hc, HASHSZ); |
973 | }) |
974 | }) |
410c8acf |
975 | } |
976 | |
00e64b67 |
977 | /* --- @checkpub@ --- * |
978 | * |
979 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
980 | * |
981 | * Returns: Zero if OK, nonzero if the peer's public key has expired. |
982 | * |
983 | * Use: Deactivates the key-exchange until the peer acquires a new |
984 | * public key. |
985 | */ |
986 | |
987 | static int checkpub(keyexch *kx) |
988 | { |
989 | time_t now; |
990 | if (kx->f & KXF_DEAD) |
991 | return (-1); |
992 | now = time(0); |
993 | if (KEY_EXPIRED(now, kx->texp_kpub)) { |
994 | stop(kx); |
995 | a_warn("public key for `%s' has expired", p_name(kx->p)); |
996 | dh_pubfree(&kx->kpub); |
997 | kx->f &= ~KXF_PUBKEY; |
998 | return (-1); |
999 | } |
1000 | return (0); |
1001 | } |
1002 | |
0617b6e7 |
1003 | /* --- @kx_start@ --- * |
410c8acf |
1004 | * |
1005 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
410c8acf |
1006 | * |
1007 | * Returns: --- |
1008 | * |
0617b6e7 |
1009 | * Use: Stimulates a key exchange. If a key exchage is in progress, |
1010 | * a new challenge is sent (unless the quiet timer forbids |
1011 | * this); if no exchange is in progress, one is commenced. |
410c8acf |
1012 | */ |
1013 | |
0617b6e7 |
1014 | void kx_start(keyexch *kx) |
410c8acf |
1015 | { |
1016 | time_t now = time(0); |
410c8acf |
1017 | |
00e64b67 |
1018 | if (checkpub(kx)) |
1019 | return; |
0617b6e7 |
1020 | if (!ISVALID(kx, now)) { |
1021 | stop(kx); |
1022 | start(kx, now); |
410c8acf |
1023 | } |
0617b6e7 |
1024 | resend(kx); |
1025 | } |
1026 | |
1027 | /* --- @kx_message@ --- * |
1028 | * |
1029 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
1030 | * @unsigned msg@ = the message code |
1031 | * @buf *b@ = pointer to buffer containing the packet |
1032 | * |
1033 | * Returns: --- |
1034 | * |
1035 | * Use: Reads a packet containing key exchange messages and handles |
1036 | * it. |
1037 | */ |
1038 | |
1039 | void kx_message(keyexch *kx, unsigned msg, buf *b) |
1040 | { |
1041 | time_t now = time(0); |
1042 | stats *st = p_stats(kx->p); |
1043 | size_t sz = BSZ(b); |
1044 | int rc; |
1045 | |
1046 | #ifndef NTRACE |
1047 | static const char *const pkname[] = { |
1048 | "prechallenge", "cookie", "challenge", |
1049 | "reply", "switch request", "switch confirmation" |
1050 | }; |
1051 | #endif |
1052 | |
00e64b67 |
1053 | if (checkpub(kx)) |
1054 | return; |
1055 | |
0617b6e7 |
1056 | if (!ISVALID(kx, now)) { |
1057 | stop(kx); |
1058 | start(kx, now); |
410c8acf |
1059 | } |
0617b6e7 |
1060 | |
1061 | T( trace(T_KEYEXCH, "keyexch: processing %s packet from `%s'", |
1062 | msg < KX_NMSG ? pkname[msg] : "unknown", p_name(kx->p)); ) |
1063 | |
1064 | switch (msg) { |
1065 | case KX_PRECHAL: |
1066 | case KX_COOKIE: |
1067 | case KX_CHAL: |
1068 | rc = dochallenge(kx, msg, b); |
1069 | break; |
1070 | case KX_REPLY: |
1071 | rc = doreply(kx, b); |
1072 | break; |
1073 | case KX_SWITCH: |
1074 | rc = doswitch(kx, b); |
1075 | break; |
1076 | case KX_SWITCHOK: |
1077 | rc = doswitchok(kx, b); |
1078 | break; |
1079 | default: |
1080 | a_warn("unexpected key exchange message type %u from `%p'", |
1081 | p_name(kx->p)); |
1082 | rc = -1; |
1083 | break; |
410c8acf |
1084 | } |
410c8acf |
1085 | |
0617b6e7 |
1086 | if (rc) |
1087 | st->n_reject++; |
1088 | else { |
1089 | st->n_kxin++; |
1090 | st->sz_kxin += sz; |
1091 | } |
410c8acf |
1092 | } |
1093 | |
1094 | /* --- @kx_free@ --- * |
1095 | * |
1096 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
1097 | * |
1098 | * Returns: --- |
1099 | * |
1100 | * Use: Frees everything in a key exchange context. |
1101 | */ |
1102 | |
1103 | void kx_free(keyexch *kx) |
1104 | { |
0617b6e7 |
1105 | stop(kx); |
00e64b67 |
1106 | if (kx->f & KXF_PUBKEY) |
1107 | dh_pubfree(&kx->kpub); |
410c8acf |
1108 | } |
1109 | |
1110 | /* --- @kx_newkeys@ --- * |
1111 | * |
1112 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
1113 | * |
1114 | * Returns: --- |
1115 | * |
1116 | * Use: Informs the key exchange module that its keys may have |
1117 | * changed. If fetching the new keys fails, the peer will be |
1118 | * destroyed, we log messages and struggle along with the old |
1119 | * keys. |
1120 | */ |
1121 | |
1122 | void kx_newkeys(keyexch *kx) |
1123 | { |
1124 | dh_pub dp; |
1125 | |
00e64b67 |
1126 | if (km_getpubkey(p_name(kx->p), &dp, &kx->texp_kpub)) |
410c8acf |
1127 | return; |
00e64b67 |
1128 | if (kx->f & KXF_PUBKEY) |
1129 | dh_pubfree(&kx->kpub); |
410c8acf |
1130 | kx->kpub = dp; |
00e64b67 |
1131 | kx->f |= KXF_PUBKEY; |
1132 | if ((kx->f & KXF_DEAD) || kx->s != KXS_SWITCH) { |
410c8acf |
1133 | T( trace(T_KEYEXCH, "keyexch: restarting key negotiation with `%s'", |
1134 | p_name(kx->p)); ) |
00e64b67 |
1135 | stop(kx); |
1136 | start(kx, time(0)); |
1137 | resend(kx); |
410c8acf |
1138 | } |
1139 | } |
1140 | |
1141 | /* --- @kx_init@ --- * |
1142 | * |
1143 | * Arguments: @keyexch *kx@ = pointer to key exchange context |
1144 | * @peer *p@ = pointer to peer context |
1145 | * @keyset **ks@ = pointer to keyset list |
1146 | * |
1147 | * Returns: Zero if OK, nonzero if it failed. |
1148 | * |
1149 | * Use: Initializes a key exchange module. The module currently |
1150 | * contains no keys, and will attempt to initiate a key |
1151 | * exchange. |
1152 | */ |
1153 | |
1154 | int kx_init(keyexch *kx, peer *p, keyset **ks) |
1155 | { |
1156 | kx->ks = ks; |
1157 | kx->p = p; |
00e64b67 |
1158 | if (km_getpubkey(p_name(p), &kx->kpub, &kx->texp_kpub)) |
410c8acf |
1159 | return (-1); |
00e64b67 |
1160 | kx->f = KXF_DEAD | KXF_PUBKEY; |
0617b6e7 |
1161 | start(kx, time(0)); |
1162 | resend(kx); |
410c8acf |
1163 | return (0); |
1164 | } |
1165 | |
1166 | /*----- That's all, folks -------------------------------------------------*/ |