410c8acf |
1 | /* -*-c-*- |
2 | * |
59d670e7 |
3 | * $Id: keyset.c,v 1.5 2001/06/19 22:07:43 mdw Exp $ |
410c8acf |
4 | * |
5 | * Handling of symmetric keysets |
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: keyset.c,v $ |
59d670e7 |
32 | * Revision 1.5 2001/06/19 22:07:43 mdw |
33 | * Change the encrypted packet format to be non-malleable. |
34 | * |
d132c651 |
35 | * Revision 1.4 2001/06/16 14:06:40 mdw |
36 | * Quantify collision probabilities for the stated data volume bounds. |
37 | * |
426c0bc6 |
38 | * Revision 1.3 2001/02/16 21:39:55 mdw |
39 | * Major overhaul. Separate functions for manipulating keysets from |
40 | * functions for manipulating keyset lists. Introduce a concept of |
41 | * listening-only keys. |
42 | * |
09585a65 |
43 | * Revision 1.2 2001/02/05 19:53:23 mdw |
44 | * Add sequence number protection. |
45 | * |
410c8acf |
46 | * Revision 1.1 2001/02/03 20:26:37 mdw |
47 | * Initial checkin. |
48 | * |
49 | */ |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
53 | #include "tripe.h" |
54 | |
55 | /*----- Tunable parameters ------------------------------------------------*/ |
56 | |
d132c651 |
57 | /* --- Note on size limits --- * |
58 | * |
59 | * For a 64-bit block cipher (e.g., Blowfish), the probability of a collision |
60 | * occurring after 32 MB is less than %$2^{-21}$%, and the probability of a |
61 | * collision occurring after 64 MB is less than %$2^{-19}$%. |
62 | */ |
63 | |
426c0bc6 |
64 | #define T_EXP MIN(60) /* Expiry time for a key */ |
65 | #define T_REGEN MIN(45) /* Regeneration time for a key */ |
66 | #define SZ_EXP MEG(64) /* Expiry data size for a key */ |
67 | #define SZ_REGEN MEG(32) /* Data size threshold for regen */ |
410c8acf |
68 | |
69 | /*----- Handy macros ------------------------------------------------------*/ |
70 | |
71 | #define KEYOK(ks, now) ((ks)->sz_exp > 0 && (ks)->t_exp > now) |
72 | |
426c0bc6 |
73 | /*----- Low-level packet encryption and decryption ------------------------*/ |
410c8acf |
74 | |
59d670e7 |
75 | /* --- Encrypted data format --- * |
76 | * |
77 | * Let %$p_i$% be the %$i$%-th plaintext message. We first compute |
78 | * |
79 | * %$c_i = \mathcal{E}\textrm{-CBC}_{K_{\text{E}}}(p_i)$% |
80 | * |
81 | * as the CBC-ciphertext of %$p_i$%, and then |
82 | * |
83 | * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(i, c_i)$% |
84 | * |
85 | * as a MAC on the %%\emph{ciphertext}%%. The message sent is then the pair |
86 | * %$(\sigma_i, c_i)$%. This construction is provably secure in the NM-CCA |
87 | * sense (assuming that the cipher is IND-CPA, and the MAC is SUF-CMA) |
88 | * [Bellare and Namprempre]. |
89 | * |
90 | * This also ensures that, assuming the key is good, we have a secure channel |
91 | * [Krawczyk]. Actually, [Krawczyk] shows that, if the cipher is either a |
92 | * simple stream cipher or a block cipher in CBC mode, we can use the MAC- |
93 | * then-encrypt scheme and still have a secure channel. However, I like the |
94 | * NM-CCA guarantee from [Bellare and Namprempre]. I'm less worried about |
95 | * the Horton Principle [Wagner and Schneier]. |
96 | */ |
97 | |
426c0bc6 |
98 | /* --- @doencrypt@ --- * |
410c8acf |
99 | * |
426c0bc6 |
100 | * Arguments: @keyset *ks@ = pointer to keyset to use |
101 | * @buf *b@ = pointer to an input buffer |
102 | * @buf *bb@ = pointer to an output buffer |
410c8acf |
103 | * |
426c0bc6 |
104 | * Returns: Zero if OK, nonzero if a new key is required. |
410c8acf |
105 | * |
426c0bc6 |
106 | * Use: Encrypts a message with the given key. We assume that the |
107 | * keyset is OK to use. |
410c8acf |
108 | */ |
109 | |
426c0bc6 |
110 | static int doencrypt(keyset *ks, buf *b, buf *bb) |
410c8acf |
111 | { |
426c0bc6 |
112 | ghash *h; |
113 | gcipher *c; |
426c0bc6 |
114 | const octet *p = BCUR(b); |
115 | size_t sz = BLEFT(b); |
59d670e7 |
116 | octet *qmac, *qseq, *qiv, *qpk; |
426c0bc6 |
117 | uint32 oseq; |
118 | size_t osz, nsz; |
119 | int rc = 0; |
120 | |
121 | /* --- Allocate the required buffer space --- */ |
122 | |
123 | c = ks->cout; |
59d670e7 |
124 | if (buf_ensure(bb, MACSZ + SEQSZ + IVSZ + sz)) |
426c0bc6 |
125 | return (0); /* Caution! */ |
59d670e7 |
126 | qmac = BCUR(bb); qseq = qmac + MACSZ; qiv = qseq + SEQSZ; qpk = qiv + IVSZ; |
127 | BSTEP(bb, MACSZ + SEQSZ + IVSZ + sz); |
426c0bc6 |
128 | |
59d670e7 |
129 | /* --- Encrypt the packet --- */ |
426c0bc6 |
130 | |
131 | oseq = ks->oseq++; STORE32(qseq, oseq); |
59d670e7 |
132 | rand_get(RAND_GLOBAL, qiv, IVSZ); |
133 | c->ops->setiv(c, qiv); |
134 | c->ops->encrypt(c, p, qpk, sz); |
426c0bc6 |
135 | IF_TRACING(T_KEYSET, { |
136 | trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u", |
137 | (unsigned long)oseq, ks->seq); |
59d670e7 |
138 | trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz); |
426c0bc6 |
139 | }) |
59d670e7 |
140 | |
141 | /* --- Now compute the MAC --- */ |
142 | |
143 | h = ks->mout->ops->init(ks->mout); |
144 | h->ops->hash(h, qseq, SEQSZ + IVSZ + sz); |
145 | memcpy(qmac, h->ops->done(h, 0), MACSZ); |
146 | h->ops->destroy(h); |
426c0bc6 |
147 | IF_TRACING(T_KEYSET, { |
59d670e7 |
148 | trace_block(T_CRYPTO, "crypto: computed MAC", qmac, MACSZ); |
426c0bc6 |
149 | }) |
150 | |
151 | /* --- Deduct the packet size from the key's data life --- */ |
152 | |
153 | osz = ks->sz_exp; |
154 | if (osz > sz) |
155 | nsz = osz - sz; |
156 | else |
157 | nsz = 0; |
158 | if (osz >= SZ_REGEN && nsz < SZ_REGEN) { |
159 | T( trace(T_KEYSET, "keyset: keyset %u data regen limit exceeded -- " |
160 | "forcing exchange", ks->seq); ) |
161 | rc = -1; |
162 | } |
163 | ks->sz_exp = nsz; |
164 | return (rc); |
410c8acf |
165 | } |
166 | |
426c0bc6 |
167 | /* --- @dodecrypt@ --- * |
410c8acf |
168 | * |
426c0bc6 |
169 | * Arguments: @keyset *ks@ = pointer to keyset to use |
170 | * @buf *b@ = pointer to an input buffer |
171 | * @buf *bb@ = pointer to an output buffer |
172 | * @uint32 *seq@ = where to store the sequence number |
410c8acf |
173 | * |
426c0bc6 |
174 | * Returns: Zero if OK, nonzero if it failed. |
410c8acf |
175 | * |
426c0bc6 |
176 | * Use: Attempts to decrypt a message with the given key. No other |
177 | * checking (e.g., sequence number checks) is performed. We |
178 | * assume that the keyset is OK to use, and that there is |
179 | * sufficient output buffer space reserved. If the decryption |
180 | * is successful, the buffer pointer is moved past the decrypted |
181 | * packet, and the packet's sequence number is stored in @*seq@. |
410c8acf |
182 | */ |
183 | |
426c0bc6 |
184 | static int dodecrypt(keyset *ks, buf *b, buf *bb, uint32 *seq) |
410c8acf |
185 | { |
59d670e7 |
186 | const octet *pmac, *piv, *pseq, *ppk; |
426c0bc6 |
187 | size_t psz = BLEFT(b); |
188 | size_t sz; |
189 | octet *q = BCUR(bb); |
190 | ghash *h; |
191 | gcipher *c = ks->cin; |
192 | size_t ivsz = c->ops->c->blksz; |
193 | octet *mac; |
194 | int eq; |
195 | |
196 | /* --- Break up the packet into its components --- */ |
197 | |
198 | if (psz < ivsz + 4) { |
199 | T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); ) |
200 | return (-1); |
410c8acf |
201 | } |
59d670e7 |
202 | sz = psz - IVSZ - SEQSZ - MACSZ; |
203 | pmac = BCUR(b); pseq = pmac + MACSZ; piv = pseq + SEQSZ; ppk = piv + IVSZ; |
426c0bc6 |
204 | |
59d670e7 |
205 | /* --- Verify the MAC on the packet --- */ |
426c0bc6 |
206 | |
426c0bc6 |
207 | h = ks->min->ops->init(ks->min); |
59d670e7 |
208 | h->ops->hash(h, pseq, SEQSZ + IVSZ + sz); |
426c0bc6 |
209 | mac = h->ops->done(h, 0); |
59d670e7 |
210 | eq = !memcmp(mac, pmac, MACSZ); |
426c0bc6 |
211 | IF_TRACING(T_KEYSET, { |
212 | trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq); |
59d670e7 |
213 | trace_block(T_CRYPTO, "crypto: computed MAC", mac, MACSZ); |
426c0bc6 |
214 | }) |
215 | h->ops->destroy(h); |
216 | if (!eq) { |
217 | IF_TRACING(T_KEYSET, { |
218 | trace(T_KEYSET, "keyset: decryption failed"); |
59d670e7 |
219 | trace_block(T_CRYPTO, "crypto: expected MAC", pmac, MACSZ); |
426c0bc6 |
220 | }) |
221 | return (-1); |
222 | } |
59d670e7 |
223 | |
224 | /* --- Decrypt the packet --- */ |
225 | |
226 | c->ops->setiv(c, piv); |
227 | c->ops->decrypt(c, ppk, q, sz); |
426c0bc6 |
228 | if (seq) |
229 | *seq = LOAD32(pseq); |
230 | IF_TRACING(T_KEYSET, { |
231 | trace(T_KEYSET, "keyset: decrypted OK (sequence = %lu)", |
232 | (unsigned long)LOAD32(pseq)); |
233 | trace_block(T_CRYPTO, "crypto: decrypted packet", q, sz); |
234 | }) |
235 | BSTEP(bb, sz); |
236 | return (0); |
410c8acf |
237 | } |
238 | |
426c0bc6 |
239 | /* --- @dosequence@ --- * |
410c8acf |
240 | * |
426c0bc6 |
241 | * Arguments: @keyset *ks@ = pointer to a keyset |
242 | * @uint32 seq@ = a sequence number from a packet |
410c8acf |
243 | * |
426c0bc6 |
244 | * Returns: Zero if the sequence number is OK, nonzero if it's not. |
410c8acf |
245 | * |
426c0bc6 |
246 | * Use: Checks a sequence number. The data in the keyset which keeps |
247 | * track of valid sequence numbers is updated if the sequence |
248 | * number given is good. It's assumed that the sequence number |
249 | * has already been checked for authenticity. |
410c8acf |
250 | */ |
251 | |
426c0bc6 |
252 | static int dosequence(keyset *ks, uint32 seq) |
410c8acf |
253 | { |
426c0bc6 |
254 | uint32 seqbit; |
255 | uint32 n; |
410c8acf |
256 | |
426c0bc6 |
257 | if (seq < ks->iseq) { |
258 | a_warn("received packet has old sequence number (possible replay)"); |
259 | return (-1); |
410c8acf |
260 | } |
426c0bc6 |
261 | if (seq >= ks->iseq + KS_SEQWINSZ) { |
262 | n = seq - (ks->iseq + KS_SEQWINSZ - 1); |
263 | if (n < KS_SEQWINSZ) |
264 | ks->iwin >>= n; |
265 | else |
266 | ks->iwin = 0; |
267 | ks->iseq += n; |
268 | } |
269 | seqbit = 1 << (seq - ks->iseq); |
270 | if (ks->iwin & seqbit) { |
271 | a_warn("received packet repeats old sequence number"); |
272 | return (-1); |
273 | } |
274 | ks->iwin |= seqbit; |
275 | return (0); |
276 | } |
277 | |
278 | /*----- Operations on a single keyset -------------------------------------*/ |
279 | |
280 | /* --- @ks_drop@ --- * |
281 | * |
282 | * Arguments: @keyset *ks@ = pointer to a keyset |
283 | * |
284 | * Returns: --- |
285 | * |
286 | * Use: Decrements a keyset's reference counter. If the counter hits |
287 | * zero, the keyset is freed. |
288 | */ |
289 | |
290 | void ks_drop(keyset *ks) |
291 | { |
292 | if (--ks->ref) |
293 | return; |
294 | ks->cin->ops->destroy(ks->cin); |
295 | ks->cout->ops->destroy(ks->cout); |
296 | ks->min->ops->destroy(ks->min); |
297 | ks->mout->ops->destroy(ks->mout); |
298 | DESTROY(ks); |
410c8acf |
299 | } |
300 | |
301 | /* --- @ks_gen@ --- * |
302 | * |
426c0bc6 |
303 | * Arguments: @const void *k@ = pointer to key material |
304 | * @size_t x, y, z@ = offsets into key material (see below) |
410c8acf |
305 | * |
426c0bc6 |
306 | * Returns: A pointer to the new keyset. |
410c8acf |
307 | * |
426c0bc6 |
308 | * Use: Derives a new keyset from the given key material. The |
309 | * offsets @x@, @y@ and @z@ separate the key material into three |
310 | * parts. Between the @k@ and @k + x@ is `my' contribution to |
311 | * the key material; between @k + x@ and @k + y@ is `your' |
312 | * contribution; and between @k + y@ and @k + z@ is a shared |
313 | * value we made together. These are used to construct two |
314 | * pairs of symmetric keys. Each pair consists of an encryption |
315 | * key and a message authentication key. One pair is used for |
316 | * outgoing messages, the other for incoming messages. |
317 | * |
318 | * The new key is marked so that it won't be selected for output |
319 | * by @ksl_encrypt@. You can still encrypt data with it by |
320 | * calling @ks_encrypt@ directly. |
410c8acf |
321 | */ |
322 | |
426c0bc6 |
323 | keyset *ks_gen(const void *k, size_t x, size_t y, size_t z) |
410c8acf |
324 | { |
426c0bc6 |
325 | HASH_CTX h; |
326 | octet buf[HASHSZ]; |
410c8acf |
327 | keyset *ks = CREATE(keyset); |
328 | time_t now = time(0); |
426c0bc6 |
329 | const octet *p = k; |
410c8acf |
330 | T( static unsigned seq = 0; ) |
331 | |
332 | T( trace(T_KEYSET, "keyset: adding new keyset %u", seq); ) |
333 | |
426c0bc6 |
334 | /* --- Construct the various keys --- * |
335 | * |
336 | * This is done with macros, because it's quite tedious. |
337 | */ |
338 | |
339 | #define MINE HASH(&h, p, x) |
340 | #define YOURS HASH(&h, p + x, y - x) |
341 | #define OURS HASH(&h, p + y, z - y) |
342 | |
343 | #define IN MINE; YOURS; OURS |
344 | #define OUT YOURS; MINE; OURS |
345 | #define STR_IN "incoming" |
346 | #define STR_OUT "outgoing" |
347 | |
348 | #define GETHASH(str, dir) do { \ |
349 | HASH_INIT(&h); \ |
350 | HASH_STRING(&h, "tripe-" str); \ |
351 | dir; \ |
352 | HASH_DONE(&h, buf); \ |
410c8acf |
353 | IF_TRACING(T_KEYSET, { \ |
426c0bc6 |
354 | trace_block(T_CRYPTO, "crypto: " STR_##dir " key " str, \ |
355 | buf, sizeof(buf)); \ |
410c8acf |
356 | }) \ |
357 | } while (0) |
358 | |
426c0bc6 |
359 | GETHASH("encryption", IN); ks->cin = CIPHER->init(buf, sizeof(buf)); |
360 | GETHASH("integrity", IN); ks->min = MAC->key(buf, sizeof(buf)); |
361 | GETHASH("encryption", OUT); ks->cout = CIPHER->init(buf, sizeof(buf)); |
362 | GETHASH("integrity", OUT); ks->mout = MAC->key(buf, sizeof(buf)); |
363 | |
364 | #undef MINE |
365 | #undef YOURS |
366 | #undef OURS |
367 | #undef IN |
368 | #undef OUT |
369 | #undef STR_IN |
370 | #undef STR_OUT |
410c8acf |
371 | #undef GETHASH |
372 | |
373 | T( ks->seq = seq++; ) |
426c0bc6 |
374 | ks->t_exp = now + T_EXP; |
375 | ks->sz_exp = SZ_EXP; |
09585a65 |
376 | ks->oseq = ks->iseq = 0; |
377 | ks->iwin = 0; |
426c0bc6 |
378 | ks->next = 0; |
379 | ks->f = KSF_LISTEN; |
410c8acf |
380 | BURN(buf); |
426c0bc6 |
381 | return (ks); |
382 | } |
383 | |
384 | /* --- @ks_tregen@ --- * |
385 | * |
386 | * Arguments: @keyset *ks@ = pointer to a keyset |
387 | * |
388 | * Returns: The time at which moves ought to be made to replace this key. |
389 | */ |
390 | |
391 | time_t ks_tregen(keyset *ks) { return (ks->t_exp - T_EXP + T_REGEN); } |
392 | |
393 | /* --- @ks_activate@ --- * |
394 | * |
395 | * Arguments: @keyset *ks@ = pointer to a keyset |
396 | * |
397 | * Returns: --- |
398 | * |
399 | * Use: Activates a keyset, so that it can be used for encrypting |
400 | * outgoing messages. |
401 | */ |
402 | |
403 | void ks_activate(keyset *ks) |
404 | { |
405 | if (ks->f & KSF_LISTEN) { |
406 | T( trace(T_KEYSET, "keyset: activating keyset %u", ks->seq); ) |
407 | ks->f &= ~KSF_LISTEN; |
408 | } |
410c8acf |
409 | } |
410 | |
411 | /* --- @ks_encrypt@ --- * |
426c0bc6 |
412 | * |
413 | * Arguments: @keyset *ks@ = pointer to a keyset |
414 | * @buf *b@ = pointer to input buffer |
415 | * @buf *bb@ = pointer to output buffer |
416 | * |
417 | * Returns: Zero if OK, nonzero if the key needs replacing. If the |
418 | * encryption failed, the output buffer is broken and zero is |
419 | * returned. |
420 | * |
421 | * Use: Encrypts a block of data using the key. Note that the `key |
422 | * ought to be replaced' notification is only ever given once |
423 | * for each key. Also note that this call forces a keyset to be |
424 | * used even if it's marked as not for data output. |
425 | */ |
426 | |
427 | int ks_encrypt(keyset *ks, buf *b, buf *bb) |
428 | { |
429 | time_t now = time(0); |
430 | |
431 | if (!KEYOK(ks, now)) { |
432 | buf_break(bb); |
433 | return (0); |
434 | } |
435 | return (doencrypt(ks, b, bb)); |
436 | } |
437 | |
438 | /* --- @ks_decrypt@ --- * |
439 | * |
440 | * Arguments: @keyset *ks@ = pointer to a keyset |
441 | * @buf *b@ = pointer to an input buffer |
442 | * @buf *bb@ = pointer to an output buffer |
443 | * |
444 | * Returns: Zero on success, or nonzero if there was some problem. |
445 | * |
446 | * Use: Attempts to decrypt a message using a given key. Note that |
447 | * requesting decryption with a key directly won't clear a |
448 | * marking that it's not for encryption. |
449 | */ |
450 | |
451 | int ks_decrypt(keyset *ks, buf *b, buf *bb) |
452 | { |
453 | time_t now = time(0); |
454 | uint32 seq; |
455 | |
456 | if (!KEYOK(ks, now) || |
457 | buf_ensure(bb, BLEN(b)) || |
458 | dodecrypt(ks, b, bb, &seq) || |
459 | dosequence(ks, seq)) |
460 | return (-1); |
461 | return (0); |
462 | } |
463 | |
464 | /*----- Keyset list handling ----------------------------------------------*/ |
465 | |
466 | /* --- @ksl_free@ --- * |
467 | * |
468 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
469 | * |
470 | * Returns: --- |
471 | * |
472 | * Use: Frees (releases references to) all of the keys in a keyset. |
473 | */ |
474 | |
475 | void ksl_free(keyset **ksroot) |
476 | { |
477 | keyset *ks, *ksn; |
478 | for (ks = *ksroot; ks; ks = ksn) { |
479 | ksn = ks->next; |
480 | ks->f &= ~KSF_LINK; |
481 | ks_drop(ks); |
482 | } |
483 | } |
484 | |
485 | /* --- @ksl_link@ --- * |
486 | * |
487 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
488 | * @keyset *ks@ = pointer to a keyset |
489 | * |
490 | * Returns: --- |
491 | * |
492 | * Use: Links a keyset into a list. A keyset can only be on one list |
493 | * at a time. Bad things happen otherwise. |
494 | */ |
495 | |
496 | void ksl_link(keyset **ksroot, keyset *ks) |
497 | { |
498 | assert(!(ks->f & KSF_LINK)); |
499 | ks->next = *ksroot; |
500 | *ksroot = ks; |
501 | ks->f |= KSF_LINK; |
502 | ks->ref++; |
503 | } |
504 | |
505 | /* --- @ksl_prune@ --- * |
506 | * |
507 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
508 | * |
509 | * Returns: --- |
510 | * |
511 | * Use: Prunes the keyset list by removing keys which mustn't be used |
512 | * any more. |
513 | */ |
514 | |
515 | void ksl_prune(keyset **ksroot) |
516 | { |
517 | time_t now = time(0); |
518 | |
519 | while (*ksroot) { |
520 | keyset *ks = *ksroot; |
521 | |
522 | if (ks->t_exp <= now) { |
523 | T( trace(T_KEYSET, "keyset: expiring keyset %u (time limit reached)", |
524 | ks->seq); ) |
525 | goto kill; |
526 | } else if (ks->sz_exp == 0) { |
527 | T( trace(T_KEYSET, "keyset: expiring keyset %u (data limit reached)", |
528 | ks->seq); ) |
529 | goto kill; |
530 | } else { |
531 | ksroot = &ks->next; |
532 | continue; |
533 | } |
534 | |
535 | kill: |
536 | *ksroot = ks->next; |
537 | ks->f &= ~KSF_LINK; |
538 | ks_drop(ks); |
539 | } |
540 | } |
541 | |
542 | /* --- @ksl_encrypt@ --- * |
410c8acf |
543 | * |
544 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
545 | * @buf *b@ = pointer to input buffer |
546 | * @buf *bb@ = pointer to output buffer |
547 | * |
548 | * Returns: Nonzero if a new key is needed. |
549 | * |
550 | * Use: Encrypts a packet. |
551 | */ |
552 | |
426c0bc6 |
553 | int ksl_encrypt(keyset **ksroot, buf *b, buf *bb) |
410c8acf |
554 | { |
555 | time_t now = time(0); |
426c0bc6 |
556 | keyset *ks = *ksroot; |
410c8acf |
557 | |
410c8acf |
558 | for (;;) { |
559 | if (!ks) { |
426c0bc6 |
560 | T( trace(T_KEYSET, "keyset: no suitable keysets found"); ) |
410c8acf |
561 | buf_break(bb); |
562 | return (-1); |
563 | } |
426c0bc6 |
564 | if (KEYOK(ks, now) && !(ks->f & KSF_LISTEN)) |
410c8acf |
565 | break; |
566 | ks = ks->next; |
567 | } |
568 | |
426c0bc6 |
569 | return (doencrypt(ks, b, bb)); |
410c8acf |
570 | } |
571 | |
426c0bc6 |
572 | /* --- @ksl_decrypt@ --- * |
410c8acf |
573 | * |
574 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
575 | * @buf *b@ = pointer to input buffer |
576 | * @buf *bb@ = pointer to output buffer |
577 | * |
578 | * Returns: Nonzero if the packet couldn't be decrypted. |
579 | * |
580 | * Use: Decrypts a packet. |
581 | */ |
582 | |
426c0bc6 |
583 | int ksl_decrypt(keyset **ksroot, buf *b, buf *bb) |
410c8acf |
584 | { |
585 | time_t now = time(0); |
410c8acf |
586 | keyset *ks; |
426c0bc6 |
587 | uint32 seq; |
410c8acf |
588 | |
426c0bc6 |
589 | if (buf_ensure(bb, BLEN(b))) |
410c8acf |
590 | return (-1); |
09585a65 |
591 | |
410c8acf |
592 | for (ks = *ksroot; ks; ks = ks->next) { |
410c8acf |
593 | if (!KEYOK(ks, now)) |
594 | continue; |
426c0bc6 |
595 | if (!dodecrypt(ks, b, bb, &seq)) { |
596 | if (ks->f & KSF_LISTEN) { |
597 | T( trace(T_KEYSET, "keyset: implicitly activating keyset %u", |
598 | ks->seq); ) |
599 | ks->f &= ~KSF_LISTEN; |
600 | } |
601 | return (dosequence(ks, seq)); |
410c8acf |
602 | } |
410c8acf |
603 | } |
604 | T( trace(T_KEYSET, "keyset: no matching keys"); ) |
605 | return (-1); |
606 | } |
607 | |
608 | /*----- That's all, folks -------------------------------------------------*/ |