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1 | /* -*-c-*- |
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2 | * |
3 | * Handling of symmetric keysets |
4 | * |
5 | * (c) 2001 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Trivial IP Encryption (TrIPE). |
11 | * |
12 | * TrIPE is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU General Public License as published by |
14 | * the Free Software Foundation; either version 2 of the License, or |
15 | * (at your option) any later version. |
e04c2d50 |
16 | * |
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17 | * TrIPE is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU General Public License for more details. |
e04c2d50 |
21 | * |
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22 | * You should have received a copy of the GNU General Public License |
23 | * along with TrIPE; if not, write to the Free Software Foundation, |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
25 | */ |
26 | |
410c8acf |
27 | /*----- Header files ------------------------------------------------------*/ |
28 | |
29 | #include "tripe.h" |
30 | |
31 | /*----- Tunable parameters ------------------------------------------------*/ |
32 | |
d132c651 |
33 | /* --- Note on size limits --- * |
34 | * |
35 | * For a 64-bit block cipher (e.g., Blowfish), the probability of a collision |
36 | * occurring after 32 MB is less than %$2^{-21}$%, and the probability of a |
b5c45da1 |
37 | * collision occurring after 64 MB is less than %$2^{-19}$%. These could be |
38 | * adjusted dependent on the encryption scheme, but it's too much pain. |
d132c651 |
39 | */ |
40 | |
426c0bc6 |
41 | #define T_EXP MIN(60) /* Expiry time for a key */ |
42 | #define T_REGEN MIN(45) /* Regeneration time for a key */ |
43 | #define SZ_EXP MEG(64) /* Expiry data size for a key */ |
44 | #define SZ_REGEN MEG(32) /* Data size threshold for regen */ |
410c8acf |
45 | |
46 | /*----- Handy macros ------------------------------------------------------*/ |
47 | |
48 | #define KEYOK(ks, now) ((ks)->sz_exp > 0 && (ks)->t_exp > now) |
49 | |
b5c45da1 |
50 | #define SEQSZ 4 /* Size of sequence number packet */ |
51 | |
426c0bc6 |
52 | /*----- Low-level packet encryption and decryption ------------------------*/ |
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53 | |
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54 | /* --- Encrypted data format --- * |
55 | * |
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56 | * Let %$p_i$% be the %$i$%-th plaintext message, with type %$t$%. We first |
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57 | * compute |
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58 | * |
59 | * %$c_i = \mathcal{E}\textrm{-CBC}_{K_{\text{E}}}(p_i)$% |
60 | * |
61 | * as the CBC-ciphertext of %$p_i$%, and then |
62 | * |
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63 | * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(t, i, c_i)$% |
59d670e7 |
64 | * |
65 | * as a MAC on the %%\emph{ciphertext}%%. The message sent is then the pair |
66 | * %$(\sigma_i, c_i)$%. This construction is provably secure in the NM-CCA |
67 | * sense (assuming that the cipher is IND-CPA, and the MAC is SUF-CMA) |
68 | * [Bellare and Namprempre]. |
69 | * |
70 | * This also ensures that, assuming the key is good, we have a secure channel |
71 | * [Krawczyk]. Actually, [Krawczyk] shows that, if the cipher is either a |
72 | * simple stream cipher or a block cipher in CBC mode, we can use the MAC- |
73 | * then-encrypt scheme and still have a secure channel. However, I like the |
74 | * NM-CCA guarantee from [Bellare and Namprempre]. I'm less worried about |
75 | * the Horton Principle [Wagner and Schneier]. |
76 | */ |
77 | |
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78 | /* --- @doencrypt@ --- * |
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79 | * |
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80 | * Arguments: @keyset *ks@ = pointer to keyset to use |
7ed14135 |
81 | * @unsigned ty@ = type of message this is |
426c0bc6 |
82 | * @buf *b@ = pointer to an input buffer |
83 | * @buf *bb@ = pointer to an output buffer |
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84 | * |
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85 | * Returns: Zero if OK, nonzero if a new key is required. |
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86 | * |
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87 | * Use: Encrypts a message with the given key. We assume that the |
88 | * keyset is OK to use. |
410c8acf |
89 | */ |
90 | |
7ed14135 |
91 | static int doencrypt(keyset *ks, unsigned ty, buf *b, buf *bb) |
410c8acf |
92 | { |
426c0bc6 |
93 | ghash *h; |
b5c45da1 |
94 | gcipher *c = ks->cout; |
426c0bc6 |
95 | const octet *p = BCUR(b); |
96 | size_t sz = BLEFT(b); |
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97 | octet *qmac, *qseq, *qiv, *qpk; |
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98 | uint32 oseq; |
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99 | size_t ivsz = GC_CLASS(c)->blksz; |
100 | size_t tagsz = ks->tagsz; |
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101 | size_t osz, nsz; |
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102 | octet t[4]; |
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103 | int rc = 0; |
104 | |
105 | /* --- Allocate the required buffer space --- */ |
106 | |
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107 | if (buf_ensure(bb, tagsz + SEQSZ + ivsz + sz)) |
426c0bc6 |
108 | return (0); /* Caution! */ |
b5c45da1 |
109 | qmac = BCUR(bb); qseq = qmac + tagsz; qiv = qseq + SEQSZ; qpk = qiv + ivsz; |
110 | BSTEP(bb, tagsz + SEQSZ + ivsz + sz); |
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111 | STORE32(t, ty); |
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112 | |
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113 | oseq = ks->oseq++; STORE32(qseq, oseq); |
426c0bc6 |
114 | IF_TRACING(T_KEYSET, { |
115 | trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u", |
116 | (unsigned long)oseq, ks->seq); |
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117 | trace_block(T_CRYPTO, "crypto: plaintext packet", p, sz); |
426c0bc6 |
118 | }) |
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119 | |
b5c45da1 |
120 | /* --- Encrypt the packet --- */ |
59d670e7 |
121 | |
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122 | if (ivsz) { |
123 | rand_get(RAND_GLOBAL, qiv, ivsz); |
124 | GC_SETIV(c, qiv); |
125 | IF_TRACING(T_KEYSET, { |
126 | trace_block(T_CRYPTO, "crypto: initialization vector", qiv, ivsz); |
127 | }) |
128 | } |
129 | GC_ENCRYPT(c, p, qpk, sz); |
426c0bc6 |
130 | IF_TRACING(T_KEYSET, { |
b5c45da1 |
131 | trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz); |
426c0bc6 |
132 | }) |
133 | |
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134 | /* --- Now compute the MAC --- */ |
135 | |
136 | if (tagsz) { |
137 | h = GM_INIT(ks->mout); |
138 | GH_HASH(h, t, sizeof(t)); |
139 | GH_HASH(h, qseq, SEQSZ + ivsz + sz); |
140 | memcpy(qmac, GH_DONE(h, 0), tagsz); |
141 | GH_DESTROY(h); |
142 | IF_TRACING(T_KEYSET, { |
143 | trace_block(T_CRYPTO, "crypto: computed MAC", qmac, tagsz); |
144 | }) |
145 | } |
146 | |
426c0bc6 |
147 | /* --- Deduct the packet size from the key's data life --- */ |
148 | |
149 | osz = ks->sz_exp; |
150 | if (osz > sz) |
151 | nsz = osz - sz; |
152 | else |
153 | nsz = 0; |
154 | if (osz >= SZ_REGEN && nsz < SZ_REGEN) { |
155 | T( trace(T_KEYSET, "keyset: keyset %u data regen limit exceeded -- " |
156 | "forcing exchange", ks->seq); ) |
157 | rc = -1; |
158 | } |
159 | ks->sz_exp = nsz; |
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160 | return (rc); |
410c8acf |
161 | } |
162 | |
426c0bc6 |
163 | /* --- @dodecrypt@ --- * |
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164 | * |
426c0bc6 |
165 | * Arguments: @keyset *ks@ = pointer to keyset to use |
7ed14135 |
166 | * @unsigned ty@ = expected type code |
426c0bc6 |
167 | * @buf *b@ = pointer to an input buffer |
168 | * @buf *bb@ = pointer to an output buffer |
169 | * @uint32 *seq@ = where to store the sequence number |
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170 | * |
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171 | * Returns: Zero if OK, nonzero if it failed. |
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172 | * |
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173 | * Use: Attempts to decrypt a message with the given key. No other |
174 | * checking (e.g., sequence number checks) is performed. We |
175 | * assume that the keyset is OK to use, and that there is |
176 | * sufficient output buffer space reserved. If the decryption |
177 | * is successful, the buffer pointer is moved past the decrypted |
178 | * packet, and the packet's sequence number is stored in @*seq@. |
410c8acf |
179 | */ |
180 | |
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181 | static int dodecrypt(keyset *ks, unsigned ty, buf *b, buf *bb, uint32 *seq) |
410c8acf |
182 | { |
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183 | const octet *pmac, *piv, *pseq, *ppk; |
426c0bc6 |
184 | size_t psz = BLEFT(b); |
185 | size_t sz; |
186 | octet *q = BCUR(bb); |
187 | ghash *h; |
188 | gcipher *c = ks->cin; |
b5c45da1 |
189 | size_t ivsz = GC_CLASS(c)->blksz; |
190 | size_t tagsz = ks->tagsz; |
426c0bc6 |
191 | octet *mac; |
192 | int eq; |
7ed14135 |
193 | octet t[4]; |
426c0bc6 |
194 | |
195 | /* --- Break up the packet into its components --- */ |
196 | |
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197 | if (psz < ivsz + SEQSZ + tagsz) { |
426c0bc6 |
198 | T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); ) |
199 | return (-1); |
410c8acf |
200 | } |
b5c45da1 |
201 | sz = psz - ivsz - SEQSZ - tagsz; |
202 | pmac = BCUR(b); pseq = pmac + tagsz; piv = pseq + SEQSZ; ppk = piv + ivsz; |
7ed14135 |
203 | STORE32(t, ty); |
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204 | |
426c0bc6 |
205 | IF_TRACING(T_KEYSET, { |
206 | trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq); |
b5c45da1 |
207 | trace_block(T_CRYPTO, "crypto: ciphertext packet", ppk, sz); |
426c0bc6 |
208 | }) |
b5c45da1 |
209 | |
210 | /* --- Verify the MAC on the packet --- */ |
211 | |
212 | if (tagsz) { |
213 | h = GM_INIT(ks->min); |
214 | GH_HASH(h, t, sizeof(t)); |
215 | GH_HASH(h, pseq, SEQSZ + ivsz + sz); |
216 | mac = GH_DONE(h, 0); |
217 | eq = !memcmp(mac, pmac, tagsz); |
426c0bc6 |
218 | IF_TRACING(T_KEYSET, { |
b5c45da1 |
219 | trace_block(T_CRYPTO, "crypto: computed MAC", mac, tagsz); |
426c0bc6 |
220 | }) |
b5c45da1 |
221 | GH_DESTROY(h); |
222 | if (!eq) { |
223 | IF_TRACING(T_KEYSET, { |
224 | trace(T_KEYSET, "keyset: incorrect MAC: decryption failed"); |
225 | trace_block(T_CRYPTO, "crypto: expected MAC", pmac, tagsz); |
226 | }) |
227 | return (-1); |
228 | } |
426c0bc6 |
229 | } |
59d670e7 |
230 | |
231 | /* --- Decrypt the packet --- */ |
232 | |
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233 | if (ivsz) { |
234 | GC_SETIV(c, piv); |
235 | IF_TRACING(T_KEYSET, { |
236 | trace_block(T_CRYPTO, "crypto: initialization vector", piv, ivsz); |
237 | }) |
238 | } |
239 | GC_DECRYPT(c, ppk, q, sz); |
426c0bc6 |
240 | if (seq) |
241 | *seq = LOAD32(pseq); |
242 | IF_TRACING(T_KEYSET, { |
243 | trace(T_KEYSET, "keyset: decrypted OK (sequence = %lu)", |
244 | (unsigned long)LOAD32(pseq)); |
245 | trace_block(T_CRYPTO, "crypto: decrypted packet", q, sz); |
246 | }) |
247 | BSTEP(bb, sz); |
248 | return (0); |
410c8acf |
249 | } |
250 | |
426c0bc6 |
251 | /*----- Operations on a single keyset -------------------------------------*/ |
252 | |
253 | /* --- @ks_drop@ --- * |
254 | * |
255 | * Arguments: @keyset *ks@ = pointer to a keyset |
256 | * |
257 | * Returns: --- |
258 | * |
259 | * Use: Decrements a keyset's reference counter. If the counter hits |
260 | * zero, the keyset is freed. |
261 | */ |
262 | |
263 | void ks_drop(keyset *ks) |
264 | { |
265 | if (--ks->ref) |
266 | return; |
b5c45da1 |
267 | GC_DESTROY(ks->cin); |
268 | GC_DESTROY(ks->cout); |
269 | GM_DESTROY(ks->min); |
270 | GM_DESTROY(ks->mout); |
426c0bc6 |
271 | DESTROY(ks); |
410c8acf |
272 | } |
273 | |
274 | /* --- @ks_gen@ --- * |
275 | * |
426c0bc6 |
276 | * Arguments: @const void *k@ = pointer to key material |
277 | * @size_t x, y, z@ = offsets into key material (see below) |
e04c2d50 |
278 | * @peer *p@ = pointer to peer information |
410c8acf |
279 | * |
426c0bc6 |
280 | * Returns: A pointer to the new keyset. |
410c8acf |
281 | * |
426c0bc6 |
282 | * Use: Derives a new keyset from the given key material. The |
283 | * offsets @x@, @y@ and @z@ separate the key material into three |
284 | * parts. Between the @k@ and @k + x@ is `my' contribution to |
285 | * the key material; between @k + x@ and @k + y@ is `your' |
286 | * contribution; and between @k + y@ and @k + z@ is a shared |
287 | * value we made together. These are used to construct two |
288 | * pairs of symmetric keys. Each pair consists of an encryption |
289 | * key and a message authentication key. One pair is used for |
290 | * outgoing messages, the other for incoming messages. |
291 | * |
292 | * The new key is marked so that it won't be selected for output |
293 | * by @ksl_encrypt@. You can still encrypt data with it by |
294 | * calling @ks_encrypt@ directly. |
410c8acf |
295 | */ |
296 | |
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297 | keyset *ks_gen(const void *k, size_t x, size_t y, size_t z, peer *p) |
410c8acf |
298 | { |
b5c45da1 |
299 | ghash *h; |
300 | const octet *hh; |
410c8acf |
301 | keyset *ks = CREATE(keyset); |
302 | time_t now = time(0); |
9466fafa |
303 | const octet *pp = k; |
410c8acf |
304 | T( static unsigned seq = 0; ) |
305 | |
306 | T( trace(T_KEYSET, "keyset: adding new keyset %u", seq); ) |
307 | |
426c0bc6 |
308 | /* --- Construct the various keys --- * |
309 | * |
310 | * This is done with macros, because it's quite tedious. |
311 | */ |
312 | |
b5c45da1 |
313 | #define MINE GH_HASH(h, pp, x) |
314 | #define YOURS GH_HASH(h, pp + x, y - x) |
315 | #define OURS GH_HASH(h, pp + y, z - y) |
316 | |
317 | #define HASH_in MINE; YOURS; OURS |
318 | #define HASH_out YOURS; MINE; OURS |
319 | #define INIT_c(k) GC_INIT(algs.c, (k), algs.cksz) |
320 | #define INIT_m(k) GM_KEY(algs.m, (k), algs.mksz) |
321 | #define STR_c "encryption" |
322 | #define STR_m "integrity" |
323 | #define STR_in "incoming" |
324 | #define STR_out "outgoing" |
325 | |
326 | #define SETKEY(a, dir) do { \ |
327 | h = GH_INIT(algs.h); \ |
328 | HASH_STRING(h, "tripe-" STR_##a); \ |
329 | HASH_##dir; \ |
330 | hh = GH_DONE(h, 0); \ |
410c8acf |
331 | IF_TRACING(T_KEYSET, { \ |
b5c45da1 |
332 | trace_block(T_CRYPTO, "crypto: " STR_##dir " key " STR_##a, \ |
333 | hh, algs.a##ksz); \ |
410c8acf |
334 | }) \ |
b5c45da1 |
335 | ks->a##dir = INIT_##a(hh); \ |
336 | GH_DESTROY(h); \ |
410c8acf |
337 | } while (0) |
338 | |
b5c45da1 |
339 | SETKEY(c, in); SETKEY(c, out); |
340 | SETKEY(m, in); SETKEY(m, out); |
426c0bc6 |
341 | |
342 | #undef MINE |
343 | #undef YOURS |
344 | #undef OURS |
b5c45da1 |
345 | #undef STR_c |
346 | #undef STR_m |
347 | #undef STR_in |
348 | #undef STR_out |
349 | #undef INIT_c |
350 | #undef INIT_m |
351 | #undef HASH_in |
352 | #undef HASH_out |
353 | #undef SETKEY |
410c8acf |
354 | |
355 | T( ks->seq = seq++; ) |
e945d6e4 |
356 | ks->ref = 1; |
426c0bc6 |
357 | ks->t_exp = now + T_EXP; |
358 | ks->sz_exp = SZ_EXP; |
37941236 |
359 | ks->oseq = 0; |
360 | seq_reset(&ks->iseq); |
426c0bc6 |
361 | ks->next = 0; |
9466fafa |
362 | ks->p = p; |
426c0bc6 |
363 | ks->f = KSF_LISTEN; |
b5c45da1 |
364 | ks->tagsz = algs.tagsz; |
426c0bc6 |
365 | return (ks); |
366 | } |
367 | |
368 | /* --- @ks_tregen@ --- * |
369 | * |
370 | * Arguments: @keyset *ks@ = pointer to a keyset |
371 | * |
372 | * Returns: The time at which moves ought to be made to replace this key. |
373 | */ |
374 | |
375 | time_t ks_tregen(keyset *ks) { return (ks->t_exp - T_EXP + T_REGEN); } |
376 | |
377 | /* --- @ks_activate@ --- * |
378 | * |
379 | * Arguments: @keyset *ks@ = pointer to a keyset |
380 | * |
381 | * Returns: --- |
382 | * |
383 | * Use: Activates a keyset, so that it can be used for encrypting |
384 | * outgoing messages. |
385 | */ |
386 | |
387 | void ks_activate(keyset *ks) |
388 | { |
389 | if (ks->f & KSF_LISTEN) { |
390 | T( trace(T_KEYSET, "keyset: activating keyset %u", ks->seq); ) |
391 | ks->f &= ~KSF_LISTEN; |
392 | } |
410c8acf |
393 | } |
394 | |
395 | /* --- @ks_encrypt@ --- * |
426c0bc6 |
396 | * |
397 | * Arguments: @keyset *ks@ = pointer to a keyset |
7ed14135 |
398 | * @unsigned ty@ = message type |
426c0bc6 |
399 | * @buf *b@ = pointer to input buffer |
400 | * @buf *bb@ = pointer to output buffer |
401 | * |
402 | * Returns: Zero if OK, nonzero if the key needs replacing. If the |
403 | * encryption failed, the output buffer is broken and zero is |
404 | * returned. |
405 | * |
406 | * Use: Encrypts a block of data using the key. Note that the `key |
407 | * ought to be replaced' notification is only ever given once |
408 | * for each key. Also note that this call forces a keyset to be |
409 | * used even if it's marked as not for data output. |
410 | */ |
411 | |
7ed14135 |
412 | int ks_encrypt(keyset *ks, unsigned ty, buf *b, buf *bb) |
426c0bc6 |
413 | { |
414 | time_t now = time(0); |
415 | |
416 | if (!KEYOK(ks, now)) { |
417 | buf_break(bb); |
418 | return (0); |
419 | } |
7ed14135 |
420 | return (doencrypt(ks, ty, b, bb)); |
426c0bc6 |
421 | } |
422 | |
423 | /* --- @ks_decrypt@ --- * |
424 | * |
425 | * Arguments: @keyset *ks@ = pointer to a keyset |
7ed14135 |
426 | * @unsigned ty@ = expected type code |
426c0bc6 |
427 | * @buf *b@ = pointer to an input buffer |
428 | * @buf *bb@ = pointer to an output buffer |
429 | * |
430 | * Returns: Zero on success, or nonzero if there was some problem. |
431 | * |
432 | * Use: Attempts to decrypt a message using a given key. Note that |
433 | * requesting decryption with a key directly won't clear a |
434 | * marking that it's not for encryption. |
435 | */ |
436 | |
7ed14135 |
437 | int ks_decrypt(keyset *ks, unsigned ty, buf *b, buf *bb) |
426c0bc6 |
438 | { |
439 | time_t now = time(0); |
440 | uint32 seq; |
441 | |
442 | if (!KEYOK(ks, now) || |
443 | buf_ensure(bb, BLEN(b)) || |
7ed14135 |
444 | dodecrypt(ks, ty, b, bb, &seq) || |
f43df819 |
445 | seq_check(&ks->iseq, seq, "SYMM")) |
426c0bc6 |
446 | return (-1); |
447 | return (0); |
448 | } |
449 | |
450 | /*----- Keyset list handling ----------------------------------------------*/ |
451 | |
452 | /* --- @ksl_free@ --- * |
453 | * |
454 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
455 | * |
456 | * Returns: --- |
457 | * |
458 | * Use: Frees (releases references to) all of the keys in a keyset. |
459 | */ |
460 | |
461 | void ksl_free(keyset **ksroot) |
462 | { |
463 | keyset *ks, *ksn; |
464 | for (ks = *ksroot; ks; ks = ksn) { |
465 | ksn = ks->next; |
466 | ks->f &= ~KSF_LINK; |
467 | ks_drop(ks); |
468 | } |
469 | } |
470 | |
471 | /* --- @ksl_link@ --- * |
472 | * |
473 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
474 | * @keyset *ks@ = pointer to a keyset |
475 | * |
476 | * Returns: --- |
477 | * |
478 | * Use: Links a keyset into a list. A keyset can only be on one list |
479 | * at a time. Bad things happen otherwise. |
480 | */ |
481 | |
482 | void ksl_link(keyset **ksroot, keyset *ks) |
483 | { |
484 | assert(!(ks->f & KSF_LINK)); |
485 | ks->next = *ksroot; |
486 | *ksroot = ks; |
487 | ks->f |= KSF_LINK; |
488 | ks->ref++; |
489 | } |
490 | |
491 | /* --- @ksl_prune@ --- * |
492 | * |
493 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
494 | * |
495 | * Returns: --- |
496 | * |
497 | * Use: Prunes the keyset list by removing keys which mustn't be used |
498 | * any more. |
499 | */ |
500 | |
501 | void ksl_prune(keyset **ksroot) |
502 | { |
503 | time_t now = time(0); |
504 | |
505 | while (*ksroot) { |
506 | keyset *ks = *ksroot; |
507 | |
508 | if (ks->t_exp <= now) { |
509 | T( trace(T_KEYSET, "keyset: expiring keyset %u (time limit reached)", |
510 | ks->seq); ) |
511 | goto kill; |
512 | } else if (ks->sz_exp == 0) { |
513 | T( trace(T_KEYSET, "keyset: expiring keyset %u (data limit reached)", |
514 | ks->seq); ) |
515 | goto kill; |
516 | } else { |
517 | ksroot = &ks->next; |
518 | continue; |
519 | } |
520 | |
521 | kill: |
522 | *ksroot = ks->next; |
523 | ks->f &= ~KSF_LINK; |
524 | ks_drop(ks); |
525 | } |
526 | } |
527 | |
528 | /* --- @ksl_encrypt@ --- * |
410c8acf |
529 | * |
530 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
7ed14135 |
531 | * @unsigned ty@ = message type |
410c8acf |
532 | * @buf *b@ = pointer to input buffer |
533 | * @buf *bb@ = pointer to output buffer |
534 | * |
535 | * Returns: Nonzero if a new key is needed. |
536 | * |
537 | * Use: Encrypts a packet. |
538 | */ |
539 | |
7ed14135 |
540 | int ksl_encrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb) |
410c8acf |
541 | { |
542 | time_t now = time(0); |
426c0bc6 |
543 | keyset *ks = *ksroot; |
410c8acf |
544 | |
410c8acf |
545 | for (;;) { |
546 | if (!ks) { |
426c0bc6 |
547 | T( trace(T_KEYSET, "keyset: no suitable keysets found"); ) |
410c8acf |
548 | buf_break(bb); |
549 | return (-1); |
550 | } |
426c0bc6 |
551 | if (KEYOK(ks, now) && !(ks->f & KSF_LISTEN)) |
410c8acf |
552 | break; |
553 | ks = ks->next; |
554 | } |
555 | |
7ed14135 |
556 | return (doencrypt(ks, ty, b, bb)); |
410c8acf |
557 | } |
558 | |
426c0bc6 |
559 | /* --- @ksl_decrypt@ --- * |
410c8acf |
560 | * |
561 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
7ed14135 |
562 | * @unsigned ty@ = expected type code |
410c8acf |
563 | * @buf *b@ = pointer to input buffer |
564 | * @buf *bb@ = pointer to output buffer |
565 | * |
566 | * Returns: Nonzero if the packet couldn't be decrypted. |
567 | * |
568 | * Use: Decrypts a packet. |
569 | */ |
570 | |
7ed14135 |
571 | int ksl_decrypt(keyset **ksroot, unsigned ty, buf *b, buf *bb) |
410c8acf |
572 | { |
573 | time_t now = time(0); |
410c8acf |
574 | keyset *ks; |
426c0bc6 |
575 | uint32 seq; |
410c8acf |
576 | |
426c0bc6 |
577 | if (buf_ensure(bb, BLEN(b))) |
410c8acf |
578 | return (-1); |
09585a65 |
579 | |
410c8acf |
580 | for (ks = *ksroot; ks; ks = ks->next) { |
410c8acf |
581 | if (!KEYOK(ks, now)) |
582 | continue; |
7ed14135 |
583 | if (!dodecrypt(ks, ty, b, bb, &seq)) { |
426c0bc6 |
584 | if (ks->f & KSF_LISTEN) { |
585 | T( trace(T_KEYSET, "keyset: implicitly activating keyset %u", |
586 | ks->seq); ) |
587 | ks->f &= ~KSF_LISTEN; |
588 | } |
f43df819 |
589 | return (seq_check(&ks->iseq, seq, "SYMM")); |
410c8acf |
590 | } |
410c8acf |
591 | } |
e945d6e4 |
592 | T( trace(T_KEYSET, "keyset: no matching keys, or incorrect MAC"); ) |
410c8acf |
593 | return (-1); |
594 | } |
595 | |
596 | /*----- That's all, folks -------------------------------------------------*/ |