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