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[tripe] / keyset.c
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410c8acf 1/* -*-c-*-
2 *
b5c45da1 3 * $Id: keyset.c,v 1.11 2004/04/18 18:08:11 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
410c8acf 29/*----- Header files ------------------------------------------------------*/
30
31#include "tripe.h"
32
33/*----- Tunable parameters ------------------------------------------------*/
34
d132c651 35/* --- Note on size limits --- *
36 *
37 * For a 64-bit block cipher (e.g., Blowfish), the probability of a collision
38 * occurring after 32 MB is less than %$2^{-21}$%, and the probability of a
b5c45da1 39 * collision occurring after 64 MB is less than %$2^{-19}$%. These could be
40 * adjusted dependent on the encryption scheme, but it's too much pain.
d132c651 41 */
42
426c0bc6 43#define T_EXP MIN(60) /* Expiry time for a key */
44#define T_REGEN MIN(45) /* Regeneration time for a key */
45#define SZ_EXP MEG(64) /* Expiry data size for a key */
46#define SZ_REGEN MEG(32) /* Data size threshold for regen */
410c8acf 47
48/*----- Handy macros ------------------------------------------------------*/
49
50#define KEYOK(ks, now) ((ks)->sz_exp > 0 && (ks)->t_exp > now)
51
b5c45da1 52#define SEQSZ 4 /* Size of sequence number packet */
53
426c0bc6 54/*----- Low-level packet encryption and decryption ------------------------*/
410c8acf 55
59d670e7 56/* --- Encrypted data format --- *
57 *
7ed14135 58 * Let %$p_i$% be the %$i$%-th plaintext message, with type %$t$%. We first
59 * compute
59d670e7 60 *
61 * %$c_i = \mathcal{E}\textrm{-CBC}_{K_{\text{E}}}(p_i)$%
62 *
63 * as the CBC-ciphertext of %$p_i$%, and then
64 *
7ed14135 65 * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(t, i, c_i)$%
59d670e7 66 *
67 * as a MAC on the %%\emph{ciphertext}%%. The message sent is then the pair
68 * %$(\sigma_i, c_i)$%. This construction is provably secure in the NM-CCA
69 * sense (assuming that the cipher is IND-CPA, and the MAC is SUF-CMA)
70 * [Bellare and Namprempre].
71 *
72 * This also ensures that, assuming the key is good, we have a secure channel
73 * [Krawczyk]. Actually, [Krawczyk] shows that, if the cipher is either a
74 * simple stream cipher or a block cipher in CBC mode, we can use the MAC-
75 * then-encrypt scheme and still have a secure channel. However, I like the
76 * NM-CCA guarantee from [Bellare and Namprempre]. I'm less worried about
77 * the Horton Principle [Wagner and Schneier].
78 */
79
426c0bc6 80/* --- @doencrypt@ --- *
410c8acf 81 *
426c0bc6 82 * Arguments: @keyset *ks@ = pointer to keyset to use
7ed14135 83 * @unsigned ty@ = type of message this is
426c0bc6 84 * @buf *b@ = pointer to an input buffer
85 * @buf *bb@ = pointer to an output buffer
410c8acf 86 *
426c0bc6 87 * Returns: Zero if OK, nonzero if a new key is required.
410c8acf 88 *
426c0bc6 89 * Use: Encrypts a message with the given key. We assume that the
90 * keyset is OK to use.
410c8acf 91 */
92
7ed14135 93static int doencrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
410c8acf 94{
426c0bc6 95 ghash *h;
b5c45da1 96 gcipher *c = ks->cout;
426c0bc6 97 const octet *p = BCUR(b);
98 size_t sz = BLEFT(b);
59d670e7 99 octet *qmac, *qseq, *qiv, *qpk;
426c0bc6 100 uint32 oseq;
b5c45da1 101 size_t ivsz = GC_CLASS(c)->blksz;
102 size_t tagsz = ks->tagsz;
426c0bc6 103 size_t osz, nsz;
7ed14135 104 octet t[4];
426c0bc6 105 int rc = 0;
106
107 /* --- Allocate the required buffer space --- */
108
b5c45da1 109 if (buf_ensure(bb, tagsz + SEQSZ + ivsz + sz))
426c0bc6 110 return (0); /* Caution! */
b5c45da1 111 qmac = BCUR(bb); qseq = qmac + tagsz; qiv = qseq + SEQSZ; qpk = qiv + ivsz;
112 BSTEP(bb, tagsz + SEQSZ + ivsz + sz);
7ed14135 113 STORE32(t, ty);
426c0bc6 114
426c0bc6 115 oseq = ks->oseq++; STORE32(qseq, oseq);
426c0bc6 116 IF_TRACING(T_KEYSET, {
117 trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u",
118 (unsigned long)oseq, ks->seq);
b5c45da1 119 trace_block(T_CRYPTO, "crypto: plaintext packet", p, sz);
426c0bc6 120 })
59d670e7 121
b5c45da1 122 /* --- Encrypt the packet --- */
59d670e7 123
b5c45da1 124 if (ivsz) {
125 rand_get(RAND_GLOBAL, qiv, ivsz);
126 GC_SETIV(c, qiv);
127 IF_TRACING(T_KEYSET, {
128 trace_block(T_CRYPTO, "crypto: initialization vector", qiv, ivsz);
129 })
130 }
131 GC_ENCRYPT(c, p, qpk, sz);
426c0bc6 132 IF_TRACING(T_KEYSET, {
b5c45da1 133 trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz);
426c0bc6 134 })
135
b5c45da1 136 /* --- Now compute the MAC --- */
137
138 if (tagsz) {
139 h = GM_INIT(ks->mout);
140 GH_HASH(h, t, sizeof(t));
141 GH_HASH(h, qseq, SEQSZ + ivsz + sz);
142 memcpy(qmac, GH_DONE(h, 0), tagsz);
143 GH_DESTROY(h);
144 IF_TRACING(T_KEYSET, {
145 trace_block(T_CRYPTO, "crypto: computed MAC", qmac, tagsz);
146 })
147 }
148
426c0bc6 149 /* --- Deduct the packet size from the key's data life --- */
150
151 osz = ks->sz_exp;
152 if (osz > sz)
153 nsz = osz - sz;
154 else
155 nsz = 0;
156 if (osz >= SZ_REGEN && nsz < SZ_REGEN) {
157 T( trace(T_KEYSET, "keyset: keyset %u data regen limit exceeded -- "
158 "forcing exchange", ks->seq); )
159 rc = -1;
160 }
161 ks->sz_exp = nsz;
162 return (rc);
410c8acf 163}
164
426c0bc6 165/* --- @dodecrypt@ --- *
410c8acf 166 *
426c0bc6 167 * Arguments: @keyset *ks@ = pointer to keyset to use
7ed14135 168 * @unsigned ty@ = expected type code
426c0bc6 169 * @buf *b@ = pointer to an input buffer
170 * @buf *bb@ = pointer to an output buffer
171 * @uint32 *seq@ = where to store the sequence number
410c8acf 172 *
426c0bc6 173 * Returns: Zero if OK, nonzero if it failed.
410c8acf 174 *
426c0bc6 175 * Use: Attempts to decrypt a message with the given key. No other
176 * checking (e.g., sequence number checks) is performed. We
177 * assume that the keyset is OK to use, and that there is
178 * sufficient output buffer space reserved. If the decryption
179 * is successful, the buffer pointer is moved past the decrypted
180 * packet, and the packet's sequence number is stored in @*seq@.
410c8acf 181 */
182
7ed14135 183static int dodecrypt(keyset *ks, unsigned ty, buf *b, buf *bb, uint32 *seq)
410c8acf 184{
59d670e7 185 const octet *pmac, *piv, *pseq, *ppk;
426c0bc6 186 size_t psz = BLEFT(b);
187 size_t sz;
188 octet *q = BCUR(bb);
189 ghash *h;
190 gcipher *c = ks->cin;
b5c45da1 191 size_t ivsz = GC_CLASS(c)->blksz;
192 size_t tagsz = ks->tagsz;
426c0bc6 193 octet *mac;
194 int eq;
7ed14135 195 octet t[4];
426c0bc6 196
197 /* --- Break up the packet into its components --- */
198
b5c45da1 199 if (psz < ivsz + SEQSZ + tagsz) {
426c0bc6 200 T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); )
201 return (-1);
410c8acf 202 }
b5c45da1 203 sz = psz - ivsz - SEQSZ - tagsz;
204 pmac = BCUR(b); pseq = pmac + tagsz; piv = pseq + SEQSZ; ppk = piv + ivsz;
7ed14135 205 STORE32(t, ty);
426c0bc6 206
426c0bc6 207 IF_TRACING(T_KEYSET, {
208 trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq);
b5c45da1 209 trace_block(T_CRYPTO, "crypto: ciphertext packet", ppk, sz);
426c0bc6 210 })
b5c45da1 211
212 /* --- Verify the MAC on the packet --- */
213
214 if (tagsz) {
215 h = GM_INIT(ks->min);
216 GH_HASH(h, t, sizeof(t));
217 GH_HASH(h, pseq, SEQSZ + ivsz + sz);
218 mac = GH_DONE(h, 0);
219 eq = !memcmp(mac, pmac, tagsz);
426c0bc6 220 IF_TRACING(T_KEYSET, {
b5c45da1 221 trace_block(T_CRYPTO, "crypto: computed MAC", mac, tagsz);
426c0bc6 222 })
b5c45da1 223 GH_DESTROY(h);
224 if (!eq) {
225 IF_TRACING(T_KEYSET, {
226 trace(T_KEYSET, "keyset: incorrect MAC: decryption failed");
227 trace_block(T_CRYPTO, "crypto: expected MAC", pmac, tagsz);
228 })
229 return (-1);
230 }
426c0bc6 231 }
59d670e7 232
233 /* --- Decrypt the packet --- */
234
b5c45da1 235 if (ivsz) {
236 GC_SETIV(c, piv);
237 IF_TRACING(T_KEYSET, {
238 trace_block(T_CRYPTO, "crypto: initialization vector", piv, ivsz);
239 })
240 }
241 GC_DECRYPT(c, ppk, q, sz);
426c0bc6 242 if (seq)
243 *seq = LOAD32(pseq);
244 IF_TRACING(T_KEYSET, {
245 trace(T_KEYSET, "keyset: decrypted OK (sequence = %lu)",
246 (unsigned long)LOAD32(pseq));
247 trace_block(T_CRYPTO, "crypto: decrypted packet", q, sz);
248 })
249 BSTEP(bb, sz);
250 return (0);
410c8acf 251}
252
426c0bc6 253/* --- @dosequence@ --- *
410c8acf 254 *
426c0bc6 255 * Arguments: @keyset *ks@ = pointer to a keyset
256 * @uint32 seq@ = a sequence number from a packet
410c8acf 257 *
426c0bc6 258 * Returns: Zero if the sequence number is OK, nonzero if it's not.
410c8acf 259 *
426c0bc6 260 * Use: Checks a sequence number. The data in the keyset which keeps
261 * track of valid sequence numbers is updated if the sequence
262 * number given is good. It's assumed that the sequence number
263 * has already been checked for authenticity.
410c8acf 264 */
265
426c0bc6 266static int dosequence(keyset *ks, uint32 seq)
410c8acf 267{
426c0bc6 268 uint32 seqbit;
269 uint32 n;
410c8acf 270
426c0bc6 271 if (seq < ks->iseq) {
272 a_warn("received packet has old sequence number (possible replay)");
273 return (-1);
410c8acf 274 }
426c0bc6 275 if (seq >= ks->iseq + KS_SEQWINSZ) {
276 n = seq - (ks->iseq + KS_SEQWINSZ - 1);
277 if (n < KS_SEQWINSZ)
278 ks->iwin >>= n;
279 else
280 ks->iwin = 0;
281 ks->iseq += n;
282 }
283 seqbit = 1 << (seq - ks->iseq);
284 if (ks->iwin & seqbit) {
285 a_warn("received packet repeats old sequence number");
286 return (-1);
287 }
288 ks->iwin |= seqbit;
289 return (0);
290}
291
292/*----- Operations on a single keyset -------------------------------------*/
293
294/* --- @ks_drop@ --- *
295 *
296 * Arguments: @keyset *ks@ = pointer to a keyset
297 *
298 * Returns: ---
299 *
300 * Use: Decrements a keyset's reference counter. If the counter hits
301 * zero, the keyset is freed.
302 */
303
304void ks_drop(keyset *ks)
305{
306 if (--ks->ref)
307 return;
b5c45da1 308 GC_DESTROY(ks->cin);
309 GC_DESTROY(ks->cout);
310 GM_DESTROY(ks->min);
311 GM_DESTROY(ks->mout);
426c0bc6 312 DESTROY(ks);
410c8acf 313}
314
315/* --- @ks_gen@ --- *
316 *
426c0bc6 317 * Arguments: @const void *k@ = pointer to key material
318 * @size_t x, y, z@ = offsets into key material (see below)
9466fafa 319 * @peer *p@ = pointer to peer information
410c8acf 320 *
426c0bc6 321 * Returns: A pointer to the new keyset.
410c8acf 322 *
426c0bc6 323 * Use: Derives a new keyset from the given key material. The
324 * offsets @x@, @y@ and @z@ separate the key material into three
325 * parts. Between the @k@ and @k + x@ is `my' contribution to
326 * the key material; between @k + x@ and @k + y@ is `your'
327 * contribution; and between @k + y@ and @k + z@ is a shared
328 * value we made together. These are used to construct two
329 * pairs of symmetric keys. Each pair consists of an encryption
330 * key and a message authentication key. One pair is used for
331 * outgoing messages, the other for incoming messages.
332 *
333 * The new key is marked so that it won't be selected for output
334 * by @ksl_encrypt@. You can still encrypt data with it by
335 * calling @ks_encrypt@ directly.
410c8acf 336 */
337
9466fafa 338keyset *ks_gen(const void *k, size_t x, size_t y, size_t z, peer *p)
410c8acf 339{
b5c45da1 340 ghash *h;
341 const octet *hh;
410c8acf 342 keyset *ks = CREATE(keyset);
343 time_t now = time(0);
9466fafa 344 const octet *pp = k;
410c8acf 345 T( static unsigned seq = 0; )
346
347 T( trace(T_KEYSET, "keyset: adding new keyset %u", seq); )
348
426c0bc6 349 /* --- Construct the various keys --- *
350 *
351 * This is done with macros, because it's quite tedious.
352 */
353
b5c45da1 354#define MINE GH_HASH(h, pp, x)
355#define YOURS GH_HASH(h, pp + x, y - x)
356#define OURS GH_HASH(h, pp + y, z - y)
357
358#define HASH_in MINE; YOURS; OURS
359#define HASH_out YOURS; MINE; OURS
360#define INIT_c(k) GC_INIT(algs.c, (k), algs.cksz)
361#define INIT_m(k) GM_KEY(algs.m, (k), algs.mksz)
362#define STR_c "encryption"
363#define STR_m "integrity"
364#define STR_in "incoming"
365#define STR_out "outgoing"
366
367#define SETKEY(a, dir) do { \
368 h = GH_INIT(algs.h); \
369 HASH_STRING(h, "tripe-" STR_##a); \
370 HASH_##dir; \
371 hh = GH_DONE(h, 0); \
410c8acf 372 IF_TRACING(T_KEYSET, { \
b5c45da1 373 trace_block(T_CRYPTO, "crypto: " STR_##dir " key " STR_##a, \
374 hh, algs.a##ksz); \
410c8acf 375 }) \
b5c45da1 376 ks->a##dir = INIT_##a(hh); \
377 GH_DESTROY(h); \
410c8acf 378} while (0)
379
b5c45da1 380 SETKEY(c, in); SETKEY(c, out);
381 SETKEY(m, in); SETKEY(m, out);
426c0bc6 382
383#undef MINE
384#undef YOURS
385#undef OURS
b5c45da1 386#undef STR_c
387#undef STR_m
388#undef STR_in
389#undef STR_out
390#undef INIT_c
391#undef INIT_m
392#undef HASH_in
393#undef HASH_out
394#undef SETKEY
410c8acf 395
396 T( ks->seq = seq++; )
e945d6e4 397 ks->ref = 1;
426c0bc6 398 ks->t_exp = now + T_EXP;
399 ks->sz_exp = SZ_EXP;
09585a65 400 ks->oseq = ks->iseq = 0;
401 ks->iwin = 0;
426c0bc6 402 ks->next = 0;
9466fafa 403 ks->p = p;
426c0bc6 404 ks->f = KSF_LISTEN;
b5c45da1 405 ks->tagsz = algs.tagsz;
426c0bc6 406 return (ks);
407}
408
409/* --- @ks_tregen@ --- *
410 *
411 * Arguments: @keyset *ks@ = pointer to a keyset
412 *
413 * Returns: The time at which moves ought to be made to replace this key.
414 */
415
416time_t ks_tregen(keyset *ks) { return (ks->t_exp - T_EXP + T_REGEN); }
417
418/* --- @ks_activate@ --- *
419 *
420 * Arguments: @keyset *ks@ = pointer to a keyset
421 *
422 * Returns: ---
423 *
424 * Use: Activates a keyset, so that it can be used for encrypting
425 * outgoing messages.
426 */
427
428void ks_activate(keyset *ks)
429{
430 if (ks->f & KSF_LISTEN) {
431 T( trace(T_KEYSET, "keyset: activating keyset %u", ks->seq); )
432 ks->f &= ~KSF_LISTEN;
433 }
410c8acf 434}
435
436/* --- @ks_encrypt@ --- *
437 *
426c0bc6 438 * Arguments: @keyset *ks@ = pointer to a keyset
7ed14135 439 * @unsigned ty@ = message type
426c0bc6 440 * @buf *b@ = pointer to input buffer
441 * @buf *bb@ = pointer to output buffer
442 *
443 * Returns: Zero if OK, nonzero if the key needs replacing. If the
444 * encryption failed, the output buffer is broken and zero is
445 * returned.
446 *
447 * Use: Encrypts a block of data using the key. Note that the `key
448 * ought to be replaced' notification is only ever given once
449 * for each key. Also note that this call forces a keyset to be
450 * used even if it's marked as not for data output.
451 */
452
7ed14135 453int ks_encrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
426c0bc6 454{
455 time_t now = time(0);
456
457 if (!KEYOK(ks, now)) {
458 buf_break(bb);
459 return (0);
460 }
7ed14135 461 return (doencrypt(ks, ty, b, bb));
426c0bc6 462}
463
464/* --- @ks_decrypt@ --- *
465 *
466 * Arguments: @keyset *ks@ = pointer to a keyset
7ed14135 467 * @unsigned ty@ = expected type code
426c0bc6 468 * @buf *b@ = pointer to an input buffer
469 * @buf *bb@ = pointer to an output buffer
470 *
471 * Returns: Zero on success, or nonzero if there was some problem.
472 *
473 * Use: Attempts to decrypt a message using a given key. Note that
474 * requesting decryption with a key directly won't clear a
475 * marking that it's not for encryption.
476 */
477
7ed14135 478int ks_decrypt(keyset *ks, unsigned ty, buf *b, buf *bb)
426c0bc6 479{
480 time_t now = time(0);
481 uint32 seq;
482
483 if (!KEYOK(ks, now) ||
484 buf_ensure(bb, BLEN(b)) ||
7ed14135 485 dodecrypt(ks, ty, b, bb, &seq) ||
426c0bc6 486 dosequence(ks, seq))
487 return (-1);
488 return (0);
489}
490
491/*----- Keyset list handling ----------------------------------------------*/
492
493/* --- @ksl_free@ --- *
494 *
495 * Arguments: @keyset **ksroot@ = pointer to keyset list head
496 *
497 * Returns: ---
498 *
499 * Use: Frees (releases references to) all of the keys in a keyset.
500 */
501
502void ksl_free(keyset **ksroot)
503{
504 keyset *ks, *ksn;
505 for (ks = *ksroot; ks; ks = ksn) {
506 ksn = ks->next;
507 ks->f &= ~KSF_LINK;
508 ks_drop(ks);
509 }
510}
511
512/* --- @ksl_link@ --- *
513 *
514 * Arguments: @keyset **ksroot@ = pointer to keyset list head
515 * @keyset *ks@ = pointer to a keyset
516 *
517 * Returns: ---
518 *
519 * Use: Links a keyset into a list. A keyset can only be on one list
520 * at a time. Bad things happen otherwise.
521 */
522
523void ksl_link(keyset **ksroot, keyset *ks)
524{
525 assert(!(ks->f & KSF_LINK));
526 ks->next = *ksroot;
527 *ksroot = ks;
528 ks->f |= KSF_LINK;
529 ks->ref++;
530}
531
532/* --- @ksl_prune@ --- *
533 *
534 * Arguments: @keyset **ksroot@ = pointer to keyset list head
535 *
536 * Returns: ---
537 *
538 * Use: Prunes the keyset list by removing keys which mustn't be used
539 * any more.
540 */
541
542void ksl_prune(keyset **ksroot)
543{
544 time_t now = time(0);
545
546 while (*ksroot) {
547 keyset *ks = *ksroot;
548
549 if (ks->t_exp <= now) {
550 T( trace(T_KEYSET, "keyset: expiring keyset %u (time limit reached)",
551 ks->seq); )
552 goto kill;
553 } else if (ks->sz_exp == 0) {
554 T( trace(T_KEYSET, "keyset: expiring keyset %u (data limit reached)",
555 ks->seq); )
556 goto kill;
557 } else {
558 ksroot = &ks->next;
559 continue;
560 }
561
562 kill:
563 *ksroot = ks->next;
564 ks->f &= ~KSF_LINK;
565 ks_drop(ks);
566 }
567}
568
569/* --- @ksl_encrypt@ --- *
570 *
410c8acf 571 * Arguments: @keyset **ksroot@ = pointer to keyset list head
7ed14135 572 * @unsigned ty@ = message type
410c8acf 573 * @buf *b@ = pointer to input buffer
574 * @buf *bb@ = pointer to output buffer
575 *
576 * Returns: Nonzero if a new key is needed.
577 *
578 * Use: Encrypts a packet.
579 */
580
7ed14135 581int ksl_encrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb)
410c8acf 582{
583 time_t now = time(0);
426c0bc6 584 keyset *ks = *ksroot;
410c8acf 585
410c8acf 586 for (;;) {
587 if (!ks) {
426c0bc6 588 T( trace(T_KEYSET, "keyset: no suitable keysets found"); )
410c8acf 589 buf_break(bb);
590 return (-1);
591 }
426c0bc6 592 if (KEYOK(ks, now) && !(ks->f & KSF_LISTEN))
410c8acf 593 break;
594 ks = ks->next;
595 }
596
7ed14135 597 return (doencrypt(ks, ty, b, bb));
410c8acf 598}
599
426c0bc6 600/* --- @ksl_decrypt@ --- *
410c8acf 601 *
602 * Arguments: @keyset **ksroot@ = pointer to keyset list head
7ed14135 603 * @unsigned ty@ = expected type code
410c8acf 604 * @buf *b@ = pointer to input buffer
605 * @buf *bb@ = pointer to output buffer
606 *
607 * Returns: Nonzero if the packet couldn't be decrypted.
608 *
609 * Use: Decrypts a packet.
610 */
611
7ed14135 612int ksl_decrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb)
410c8acf 613{
614 time_t now = time(0);
410c8acf 615 keyset *ks;
426c0bc6 616 uint32 seq;
410c8acf 617
426c0bc6 618 if (buf_ensure(bb, BLEN(b)))
410c8acf 619 return (-1);
09585a65 620
410c8acf 621 for (ks = *ksroot; ks; ks = ks->next) {
410c8acf 622 if (!KEYOK(ks, now))
623 continue;
7ed14135 624 if (!dodecrypt(ks, ty, b, bb, &seq)) {
426c0bc6 625 if (ks->f & KSF_LISTEN) {
626 T( trace(T_KEYSET, "keyset: implicitly activating keyset %u",
627 ks->seq); )
628 ks->f &= ~KSF_LISTEN;
629 }
630 return (dosequence(ks, seq));
410c8acf 631 }
410c8acf 632 }
e945d6e4 633 T( trace(T_KEYSET, "keyset: no matching keys, or incorrect MAC"); )
410c8acf 634 return (-1);
635}
636
637/*----- That's all, folks -------------------------------------------------*/