410c8acf |
1 | /* -*-c-*- |
2 | * |
b4e56668 |
3 | * $Id: keyset.c,v 1.10 2004/04/08 01:36:17 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 |
39 | * collision occurring after 64 MB is less than %$2^{-19}$%. |
40 | */ |
41 | |
426c0bc6 |
42 | #define T_EXP MIN(60) /* Expiry time for a key */ |
43 | #define T_REGEN MIN(45) /* Regeneration time for a key */ |
44 | #define SZ_EXP MEG(64) /* Expiry data size for a key */ |
45 | #define SZ_REGEN MEG(32) /* Data size threshold for regen */ |
410c8acf |
46 | |
47 | /*----- Handy macros ------------------------------------------------------*/ |
48 | |
49 | #define KEYOK(ks, now) ((ks)->sz_exp > 0 && (ks)->t_exp > now) |
50 | |
426c0bc6 |
51 | /*----- Low-level packet encryption and decryption ------------------------*/ |
410c8acf |
52 | |
59d670e7 |
53 | /* --- Encrypted data format --- * |
54 | * |
7ed14135 |
55 | * Let %$p_i$% be the %$i$%-th plaintext message, with type %$t$%. We first |
56 | * compute |
59d670e7 |
57 | * |
58 | * %$c_i = \mathcal{E}\textrm{-CBC}_{K_{\text{E}}}(p_i)$% |
59 | * |
60 | * as the CBC-ciphertext of %$p_i$%, and then |
61 | * |
7ed14135 |
62 | * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(t, i, c_i)$% |
59d670e7 |
63 | * |
64 | * as a MAC on the %%\emph{ciphertext}%%. The message sent is then the pair |
65 | * %$(\sigma_i, c_i)$%. This construction is provably secure in the NM-CCA |
66 | * sense (assuming that the cipher is IND-CPA, and the MAC is SUF-CMA) |
67 | * [Bellare and Namprempre]. |
68 | * |
69 | * This also ensures that, assuming the key is good, we have a secure channel |
70 | * [Krawczyk]. Actually, [Krawczyk] shows that, if the cipher is either a |
71 | * simple stream cipher or a block cipher in CBC mode, we can use the MAC- |
72 | * then-encrypt scheme and still have a secure channel. However, I like the |
73 | * NM-CCA guarantee from [Bellare and Namprempre]. I'm less worried about |
74 | * the Horton Principle [Wagner and Schneier]. |
75 | */ |
76 | |
426c0bc6 |
77 | /* --- @doencrypt@ --- * |
410c8acf |
78 | * |
426c0bc6 |
79 | * Arguments: @keyset *ks@ = pointer to keyset to use |
7ed14135 |
80 | * @unsigned ty@ = type of message this is |
426c0bc6 |
81 | * @buf *b@ = pointer to an input buffer |
82 | * @buf *bb@ = pointer to an output buffer |
410c8acf |
83 | * |
426c0bc6 |
84 | * Returns: Zero if OK, nonzero if a new key is required. |
410c8acf |
85 | * |
426c0bc6 |
86 | * Use: Encrypts a message with the given key. We assume that the |
87 | * keyset is OK to use. |
410c8acf |
88 | */ |
89 | |
7ed14135 |
90 | static int doencrypt(keyset *ks, unsigned ty, buf *b, buf *bb) |
410c8acf |
91 | { |
426c0bc6 |
92 | ghash *h; |
93 | gcipher *c; |
426c0bc6 |
94 | const octet *p = BCUR(b); |
95 | size_t sz = BLEFT(b); |
59d670e7 |
96 | octet *qmac, *qseq, *qiv, *qpk; |
426c0bc6 |
97 | uint32 oseq; |
98 | size_t osz, nsz; |
7ed14135 |
99 | octet t[4]; |
426c0bc6 |
100 | int rc = 0; |
101 | |
102 | /* --- Allocate the required buffer space --- */ |
103 | |
104 | c = ks->cout; |
59d670e7 |
105 | if (buf_ensure(bb, MACSZ + SEQSZ + IVSZ + sz)) |
426c0bc6 |
106 | return (0); /* Caution! */ |
59d670e7 |
107 | qmac = BCUR(bb); qseq = qmac + MACSZ; qiv = qseq + SEQSZ; qpk = qiv + IVSZ; |
108 | BSTEP(bb, MACSZ + SEQSZ + IVSZ + sz); |
7ed14135 |
109 | STORE32(t, ty); |
426c0bc6 |
110 | |
59d670e7 |
111 | /* --- Encrypt the packet --- */ |
426c0bc6 |
112 | |
113 | oseq = ks->oseq++; STORE32(qseq, oseq); |
59d670e7 |
114 | rand_get(RAND_GLOBAL, qiv, IVSZ); |
115 | c->ops->setiv(c, qiv); |
116 | c->ops->encrypt(c, p, qpk, sz); |
426c0bc6 |
117 | IF_TRACING(T_KEYSET, { |
118 | trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u", |
119 | (unsigned long)oseq, ks->seq); |
59d670e7 |
120 | trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz); |
426c0bc6 |
121 | }) |
59d670e7 |
122 | |
123 | /* --- Now compute the MAC --- */ |
124 | |
125 | h = ks->mout->ops->init(ks->mout); |
7ed14135 |
126 | h->ops->hash(h, t, sizeof(t)); |
59d670e7 |
127 | h->ops->hash(h, qseq, SEQSZ + IVSZ + sz); |
128 | memcpy(qmac, h->ops->done(h, 0), MACSZ); |
129 | h->ops->destroy(h); |
426c0bc6 |
130 | IF_TRACING(T_KEYSET, { |
59d670e7 |
131 | trace_block(T_CRYPTO, "crypto: computed MAC", qmac, MACSZ); |
426c0bc6 |
132 | }) |
133 | |
134 | /* --- Deduct the packet size from the key's data life --- */ |
135 | |
136 | osz = ks->sz_exp; |
137 | if (osz > sz) |
138 | nsz = osz - sz; |
139 | else |
140 | nsz = 0; |
141 | if (osz >= SZ_REGEN && nsz < SZ_REGEN) { |
142 | T( trace(T_KEYSET, "keyset: keyset %u data regen limit exceeded -- " |
143 | "forcing exchange", ks->seq); ) |
144 | rc = -1; |
145 | } |
146 | ks->sz_exp = nsz; |
147 | return (rc); |
410c8acf |
148 | } |
149 | |
426c0bc6 |
150 | /* --- @dodecrypt@ --- * |
410c8acf |
151 | * |
426c0bc6 |
152 | * Arguments: @keyset *ks@ = pointer to keyset to use |
7ed14135 |
153 | * @unsigned ty@ = expected type code |
426c0bc6 |
154 | * @buf *b@ = pointer to an input buffer |
155 | * @buf *bb@ = pointer to an output buffer |
156 | * @uint32 *seq@ = where to store the sequence number |
410c8acf |
157 | * |
426c0bc6 |
158 | * Returns: Zero if OK, nonzero if it failed. |
410c8acf |
159 | * |
426c0bc6 |
160 | * Use: Attempts to decrypt a message with the given key. No other |
161 | * checking (e.g., sequence number checks) is performed. We |
162 | * assume that the keyset is OK to use, and that there is |
163 | * sufficient output buffer space reserved. If the decryption |
164 | * is successful, the buffer pointer is moved past the decrypted |
165 | * packet, and the packet's sequence number is stored in @*seq@. |
410c8acf |
166 | */ |
167 | |
7ed14135 |
168 | static int dodecrypt(keyset *ks, unsigned ty, buf *b, buf *bb, uint32 *seq) |
410c8acf |
169 | { |
59d670e7 |
170 | const octet *pmac, *piv, *pseq, *ppk; |
426c0bc6 |
171 | size_t psz = BLEFT(b); |
172 | size_t sz; |
173 | octet *q = BCUR(bb); |
174 | ghash *h; |
175 | gcipher *c = ks->cin; |
176 | size_t ivsz = c->ops->c->blksz; |
177 | octet *mac; |
178 | int eq; |
7ed14135 |
179 | octet t[4]; |
426c0bc6 |
180 | |
181 | /* --- Break up the packet into its components --- */ |
182 | |
183 | if (psz < ivsz + 4) { |
184 | T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); ) |
185 | return (-1); |
410c8acf |
186 | } |
59d670e7 |
187 | sz = psz - IVSZ - SEQSZ - MACSZ; |
188 | pmac = BCUR(b); pseq = pmac + MACSZ; piv = pseq + SEQSZ; ppk = piv + IVSZ; |
7ed14135 |
189 | STORE32(t, ty); |
426c0bc6 |
190 | |
59d670e7 |
191 | /* --- Verify the MAC on the packet --- */ |
426c0bc6 |
192 | |
426c0bc6 |
193 | h = ks->min->ops->init(ks->min); |
7ed14135 |
194 | h->ops->hash(h, t, sizeof(t)); |
59d670e7 |
195 | h->ops->hash(h, pseq, SEQSZ + IVSZ + sz); |
426c0bc6 |
196 | mac = h->ops->done(h, 0); |
59d670e7 |
197 | eq = !memcmp(mac, pmac, MACSZ); |
426c0bc6 |
198 | IF_TRACING(T_KEYSET, { |
199 | trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq); |
59d670e7 |
200 | trace_block(T_CRYPTO, "crypto: computed MAC", mac, MACSZ); |
426c0bc6 |
201 | }) |
202 | h->ops->destroy(h); |
203 | if (!eq) { |
204 | IF_TRACING(T_KEYSET, { |
e945d6e4 |
205 | trace(T_KEYSET, "keyset: incorrect MAC: decryption failed"); |
59d670e7 |
206 | trace_block(T_CRYPTO, "crypto: expected MAC", pmac, MACSZ); |
426c0bc6 |
207 | }) |
208 | return (-1); |
209 | } |
59d670e7 |
210 | |
211 | /* --- Decrypt the packet --- */ |
212 | |
213 | c->ops->setiv(c, piv); |
214 | c->ops->decrypt(c, ppk, q, sz); |
426c0bc6 |
215 | if (seq) |
216 | *seq = LOAD32(pseq); |
217 | IF_TRACING(T_KEYSET, { |
218 | trace(T_KEYSET, "keyset: decrypted OK (sequence = %lu)", |
219 | (unsigned long)LOAD32(pseq)); |
220 | trace_block(T_CRYPTO, "crypto: decrypted packet", q, sz); |
221 | }) |
222 | BSTEP(bb, sz); |
223 | return (0); |
410c8acf |
224 | } |
225 | |
426c0bc6 |
226 | /* --- @dosequence@ --- * |
410c8acf |
227 | * |
426c0bc6 |
228 | * Arguments: @keyset *ks@ = pointer to a keyset |
229 | * @uint32 seq@ = a sequence number from a packet |
410c8acf |
230 | * |
426c0bc6 |
231 | * Returns: Zero if the sequence number is OK, nonzero if it's not. |
410c8acf |
232 | * |
426c0bc6 |
233 | * Use: Checks a sequence number. The data in the keyset which keeps |
234 | * track of valid sequence numbers is updated if the sequence |
235 | * number given is good. It's assumed that the sequence number |
236 | * has already been checked for authenticity. |
410c8acf |
237 | */ |
238 | |
426c0bc6 |
239 | static int dosequence(keyset *ks, uint32 seq) |
410c8acf |
240 | { |
426c0bc6 |
241 | uint32 seqbit; |
242 | uint32 n; |
410c8acf |
243 | |
426c0bc6 |
244 | if (seq < ks->iseq) { |
245 | a_warn("received packet has old sequence number (possible replay)"); |
246 | return (-1); |
410c8acf |
247 | } |
426c0bc6 |
248 | if (seq >= ks->iseq + KS_SEQWINSZ) { |
249 | n = seq - (ks->iseq + KS_SEQWINSZ - 1); |
250 | if (n < KS_SEQWINSZ) |
251 | ks->iwin >>= n; |
252 | else |
253 | ks->iwin = 0; |
254 | ks->iseq += n; |
255 | } |
256 | seqbit = 1 << (seq - ks->iseq); |
257 | if (ks->iwin & seqbit) { |
258 | a_warn("received packet repeats old sequence number"); |
259 | return (-1); |
260 | } |
261 | ks->iwin |= seqbit; |
262 | return (0); |
263 | } |
264 | |
265 | /*----- Operations on a single keyset -------------------------------------*/ |
266 | |
267 | /* --- @ks_drop@ --- * |
268 | * |
269 | * Arguments: @keyset *ks@ = pointer to a keyset |
270 | * |
271 | * Returns: --- |
272 | * |
273 | * Use: Decrements a keyset's reference counter. If the counter hits |
274 | * zero, the keyset is freed. |
275 | */ |
276 | |
277 | void ks_drop(keyset *ks) |
278 | { |
279 | if (--ks->ref) |
280 | return; |
281 | ks->cin->ops->destroy(ks->cin); |
282 | ks->cout->ops->destroy(ks->cout); |
283 | ks->min->ops->destroy(ks->min); |
284 | ks->mout->ops->destroy(ks->mout); |
285 | DESTROY(ks); |
410c8acf |
286 | } |
287 | |
288 | /* --- @ks_gen@ --- * |
289 | * |
426c0bc6 |
290 | * Arguments: @const void *k@ = pointer to key material |
291 | * @size_t x, y, z@ = offsets into key material (see below) |
9466fafa |
292 | * @peer *p@ = pointer to peer information |
410c8acf |
293 | * |
426c0bc6 |
294 | * Returns: A pointer to the new keyset. |
410c8acf |
295 | * |
426c0bc6 |
296 | * Use: Derives a new keyset from the given key material. The |
297 | * offsets @x@, @y@ and @z@ separate the key material into three |
298 | * parts. Between the @k@ and @k + x@ is `my' contribution to |
299 | * the key material; between @k + x@ and @k + y@ is `your' |
300 | * contribution; and between @k + y@ and @k + z@ is a shared |
301 | * value we made together. These are used to construct two |
302 | * pairs of symmetric keys. Each pair consists of an encryption |
303 | * key and a message authentication key. One pair is used for |
304 | * outgoing messages, the other for incoming messages. |
305 | * |
306 | * The new key is marked so that it won't be selected for output |
307 | * by @ksl_encrypt@. You can still encrypt data with it by |
308 | * calling @ks_encrypt@ directly. |
410c8acf |
309 | */ |
310 | |
9466fafa |
311 | keyset *ks_gen(const void *k, size_t x, size_t y, size_t z, peer *p) |
410c8acf |
312 | { |
426c0bc6 |
313 | HASH_CTX h; |
314 | octet buf[HASHSZ]; |
410c8acf |
315 | keyset *ks = CREATE(keyset); |
316 | time_t now = time(0); |
9466fafa |
317 | const octet *pp = k; |
410c8acf |
318 | T( static unsigned seq = 0; ) |
319 | |
320 | T( trace(T_KEYSET, "keyset: adding new keyset %u", seq); ) |
321 | |
426c0bc6 |
322 | /* --- Construct the various keys --- * |
323 | * |
324 | * This is done with macros, because it's quite tedious. |
325 | */ |
326 | |
9466fafa |
327 | #define MINE HASH(&h, pp, x) |
328 | #define YOURS HASH(&h, pp + x, y - x) |
329 | #define OURS HASH(&h, pp + y, z - y) |
426c0bc6 |
330 | |
331 | #define IN MINE; YOURS; OURS |
332 | #define OUT YOURS; MINE; OURS |
333 | #define STR_IN "incoming" |
334 | #define STR_OUT "outgoing" |
335 | |
336 | #define GETHASH(str, dir) do { \ |
337 | HASH_INIT(&h); \ |
338 | HASH_STRING(&h, "tripe-" str); \ |
339 | dir; \ |
340 | HASH_DONE(&h, buf); \ |
410c8acf |
341 | IF_TRACING(T_KEYSET, { \ |
426c0bc6 |
342 | trace_block(T_CRYPTO, "crypto: " STR_##dir " key " str, \ |
343 | buf, sizeof(buf)); \ |
410c8acf |
344 | }) \ |
345 | } while (0) |
346 | |
426c0bc6 |
347 | GETHASH("encryption", IN); ks->cin = CIPHER->init(buf, sizeof(buf)); |
348 | GETHASH("integrity", IN); ks->min = MAC->key(buf, sizeof(buf)); |
349 | GETHASH("encryption", OUT); ks->cout = CIPHER->init(buf, sizeof(buf)); |
350 | GETHASH("integrity", OUT); ks->mout = MAC->key(buf, sizeof(buf)); |
351 | |
352 | #undef MINE |
353 | #undef YOURS |
354 | #undef OURS |
355 | #undef IN |
356 | #undef OUT |
357 | #undef STR_IN |
358 | #undef STR_OUT |
410c8acf |
359 | #undef GETHASH |
360 | |
361 | T( ks->seq = seq++; ) |
e945d6e4 |
362 | ks->ref = 1; |
426c0bc6 |
363 | ks->t_exp = now + T_EXP; |
364 | ks->sz_exp = SZ_EXP; |
09585a65 |
365 | ks->oseq = ks->iseq = 0; |
366 | ks->iwin = 0; |
426c0bc6 |
367 | ks->next = 0; |
9466fafa |
368 | ks->p = p; |
426c0bc6 |
369 | ks->f = KSF_LISTEN; |
410c8acf |
370 | BURN(buf); |
426c0bc6 |
371 | return (ks); |
372 | } |
373 | |
374 | /* --- @ks_tregen@ --- * |
375 | * |
376 | * Arguments: @keyset *ks@ = pointer to a keyset |
377 | * |
378 | * Returns: The time at which moves ought to be made to replace this key. |
379 | */ |
380 | |
381 | time_t ks_tregen(keyset *ks) { return (ks->t_exp - T_EXP + T_REGEN); } |
382 | |
383 | /* --- @ks_activate@ --- * |
384 | * |
385 | * Arguments: @keyset *ks@ = pointer to a keyset |
386 | * |
387 | * Returns: --- |
388 | * |
389 | * Use: Activates a keyset, so that it can be used for encrypting |
390 | * outgoing messages. |
391 | */ |
392 | |
393 | void ks_activate(keyset *ks) |
394 | { |
395 | if (ks->f & KSF_LISTEN) { |
396 | T( trace(T_KEYSET, "keyset: activating keyset %u", ks->seq); ) |
397 | ks->f &= ~KSF_LISTEN; |
398 | } |
410c8acf |
399 | } |
400 | |
401 | /* --- @ks_encrypt@ --- * |
426c0bc6 |
402 | * |
403 | * Arguments: @keyset *ks@ = pointer to a keyset |
7ed14135 |
404 | * @unsigned ty@ = message type |
426c0bc6 |
405 | * @buf *b@ = pointer to input buffer |
406 | * @buf *bb@ = pointer to output buffer |
407 | * |
408 | * Returns: Zero if OK, nonzero if the key needs replacing. If the |
409 | * encryption failed, the output buffer is broken and zero is |
410 | * returned. |
411 | * |
412 | * Use: Encrypts a block of data using the key. Note that the `key |
413 | * ought to be replaced' notification is only ever given once |
414 | * for each key. Also note that this call forces a keyset to be |
415 | * used even if it's marked as not for data output. |
416 | */ |
417 | |
7ed14135 |
418 | int ks_encrypt(keyset *ks, unsigned ty, buf *b, buf *bb) |
426c0bc6 |
419 | { |
420 | time_t now = time(0); |
421 | |
422 | if (!KEYOK(ks, now)) { |
423 | buf_break(bb); |
424 | return (0); |
425 | } |
7ed14135 |
426 | return (doencrypt(ks, ty, b, bb)); |
426c0bc6 |
427 | } |
428 | |
429 | /* --- @ks_decrypt@ --- * |
430 | * |
431 | * Arguments: @keyset *ks@ = pointer to a keyset |
7ed14135 |
432 | * @unsigned ty@ = expected type code |
426c0bc6 |
433 | * @buf *b@ = pointer to an input buffer |
434 | * @buf *bb@ = pointer to an output buffer |
435 | * |
436 | * Returns: Zero on success, or nonzero if there was some problem. |
437 | * |
438 | * Use: Attempts to decrypt a message using a given key. Note that |
439 | * requesting decryption with a key directly won't clear a |
440 | * marking that it's not for encryption. |
441 | */ |
442 | |
7ed14135 |
443 | int ks_decrypt(keyset *ks, unsigned ty, buf *b, buf *bb) |
426c0bc6 |
444 | { |
445 | time_t now = time(0); |
446 | uint32 seq; |
447 | |
448 | if (!KEYOK(ks, now) || |
449 | buf_ensure(bb, BLEN(b)) || |
7ed14135 |
450 | dodecrypt(ks, ty, b, bb, &seq) || |
426c0bc6 |
451 | dosequence(ks, seq)) |
452 | return (-1); |
453 | return (0); |
454 | } |
455 | |
456 | /*----- Keyset list handling ----------------------------------------------*/ |
457 | |
458 | /* --- @ksl_free@ --- * |
459 | * |
460 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
461 | * |
462 | * Returns: --- |
463 | * |
464 | * Use: Frees (releases references to) all of the keys in a keyset. |
465 | */ |
466 | |
467 | void ksl_free(keyset **ksroot) |
468 | { |
469 | keyset *ks, *ksn; |
470 | for (ks = *ksroot; ks; ks = ksn) { |
471 | ksn = ks->next; |
472 | ks->f &= ~KSF_LINK; |
473 | ks_drop(ks); |
474 | } |
475 | } |
476 | |
477 | /* --- @ksl_link@ --- * |
478 | * |
479 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
480 | * @keyset *ks@ = pointer to a keyset |
481 | * |
482 | * Returns: --- |
483 | * |
484 | * Use: Links a keyset into a list. A keyset can only be on one list |
485 | * at a time. Bad things happen otherwise. |
486 | */ |
487 | |
488 | void ksl_link(keyset **ksroot, keyset *ks) |
489 | { |
490 | assert(!(ks->f & KSF_LINK)); |
491 | ks->next = *ksroot; |
492 | *ksroot = ks; |
493 | ks->f |= KSF_LINK; |
494 | ks->ref++; |
495 | } |
496 | |
497 | /* --- @ksl_prune@ --- * |
498 | * |
499 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
500 | * |
501 | * Returns: --- |
502 | * |
503 | * Use: Prunes the keyset list by removing keys which mustn't be used |
504 | * any more. |
505 | */ |
506 | |
507 | void ksl_prune(keyset **ksroot) |
508 | { |
509 | time_t now = time(0); |
510 | |
511 | while (*ksroot) { |
512 | keyset *ks = *ksroot; |
513 | |
514 | if (ks->t_exp <= now) { |
515 | T( trace(T_KEYSET, "keyset: expiring keyset %u (time limit reached)", |
516 | ks->seq); ) |
517 | goto kill; |
518 | } else if (ks->sz_exp == 0) { |
519 | T( trace(T_KEYSET, "keyset: expiring keyset %u (data limit reached)", |
520 | ks->seq); ) |
521 | goto kill; |
522 | } else { |
523 | ksroot = &ks->next; |
524 | continue; |
525 | } |
526 | |
527 | kill: |
528 | *ksroot = ks->next; |
529 | ks->f &= ~KSF_LINK; |
530 | ks_drop(ks); |
531 | } |
532 | } |
533 | |
534 | /* --- @ksl_encrypt@ --- * |
410c8acf |
535 | * |
536 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
7ed14135 |
537 | * @unsigned ty@ = message type |
410c8acf |
538 | * @buf *b@ = pointer to input buffer |
539 | * @buf *bb@ = pointer to output buffer |
540 | * |
541 | * Returns: Nonzero if a new key is needed. |
542 | * |
543 | * Use: Encrypts a packet. |
544 | */ |
545 | |
7ed14135 |
546 | int ksl_encrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb) |
410c8acf |
547 | { |
548 | time_t now = time(0); |
426c0bc6 |
549 | keyset *ks = *ksroot; |
410c8acf |
550 | |
410c8acf |
551 | for (;;) { |
552 | if (!ks) { |
426c0bc6 |
553 | T( trace(T_KEYSET, "keyset: no suitable keysets found"); ) |
410c8acf |
554 | buf_break(bb); |
555 | return (-1); |
556 | } |
426c0bc6 |
557 | if (KEYOK(ks, now) && !(ks->f & KSF_LISTEN)) |
410c8acf |
558 | break; |
559 | ks = ks->next; |
560 | } |
561 | |
7ed14135 |
562 | return (doencrypt(ks, ty, b, bb)); |
410c8acf |
563 | } |
564 | |
426c0bc6 |
565 | /* --- @ksl_decrypt@ --- * |
410c8acf |
566 | * |
567 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
7ed14135 |
568 | * @unsigned ty@ = expected type code |
410c8acf |
569 | * @buf *b@ = pointer to input buffer |
570 | * @buf *bb@ = pointer to output buffer |
571 | * |
572 | * Returns: Nonzero if the packet couldn't be decrypted. |
573 | * |
574 | * Use: Decrypts a packet. |
575 | */ |
576 | |
7ed14135 |
577 | int ksl_decrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb) |
410c8acf |
578 | { |
579 | time_t now = time(0); |
410c8acf |
580 | keyset *ks; |
426c0bc6 |
581 | uint32 seq; |
410c8acf |
582 | |
426c0bc6 |
583 | if (buf_ensure(bb, BLEN(b))) |
410c8acf |
584 | return (-1); |
09585a65 |
585 | |
410c8acf |
586 | for (ks = *ksroot; ks; ks = ks->next) { |
410c8acf |
587 | if (!KEYOK(ks, now)) |
588 | continue; |
7ed14135 |
589 | if (!dodecrypt(ks, ty, b, bb, &seq)) { |
426c0bc6 |
590 | if (ks->f & KSF_LISTEN) { |
591 | T( trace(T_KEYSET, "keyset: implicitly activating keyset %u", |
592 | ks->seq); ) |
593 | ks->f &= ~KSF_LISTEN; |
594 | } |
595 | return (dosequence(ks, seq)); |
410c8acf |
596 | } |
410c8acf |
597 | } |
e945d6e4 |
598 | T( trace(T_KEYSET, "keyset: no matching keys, or incorrect MAC"); ) |
410c8acf |
599 | return (-1); |
600 | } |
601 | |
602 | /*----- That's all, folks -------------------------------------------------*/ |