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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: keyset.c,v 1.6 2003/04/06 10:26:35 mdw Exp $ |
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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 $ |
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32 | * Revision 1.6 2003/04/06 10:26:35 mdw |
33 | * Report peer name on decrypt errors. |
34 | * |
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35 | * Revision 1.5 2001/06/19 22:07:43 mdw |
36 | * Change the encrypted packet format to be non-malleable. |
37 | * |
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38 | * Revision 1.4 2001/06/16 14:06:40 mdw |
39 | * Quantify collision probabilities for the stated data volume bounds. |
40 | * |
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41 | * Revision 1.3 2001/02/16 21:39:55 mdw |
42 | * Major overhaul. Separate functions for manipulating keysets from |
43 | * functions for manipulating keyset lists. Introduce a concept of |
44 | * listening-only keys. |
45 | * |
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46 | * Revision 1.2 2001/02/05 19:53:23 mdw |
47 | * Add sequence number protection. |
48 | * |
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49 | * Revision 1.1 2001/02/03 20:26:37 mdw |
50 | * Initial checkin. |
51 | * |
52 | */ |
53 | |
54 | /*----- Header files ------------------------------------------------------*/ |
55 | |
56 | #include "tripe.h" |
57 | |
58 | /*----- Tunable parameters ------------------------------------------------*/ |
59 | |
d132c651 |
60 | /* --- Note on size limits --- * |
61 | * |
62 | * For a 64-bit block cipher (e.g., Blowfish), the probability of a collision |
63 | * occurring after 32 MB is less than %$2^{-21}$%, and the probability of a |
64 | * collision occurring after 64 MB is less than %$2^{-19}$%. |
65 | */ |
66 | |
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67 | #define T_EXP MIN(60) /* Expiry time for a key */ |
68 | #define T_REGEN MIN(45) /* Regeneration time for a key */ |
69 | #define SZ_EXP MEG(64) /* Expiry data size for a key */ |
70 | #define SZ_REGEN MEG(32) /* Data size threshold for regen */ |
410c8acf |
71 | |
72 | /*----- Handy macros ------------------------------------------------------*/ |
73 | |
74 | #define KEYOK(ks, now) ((ks)->sz_exp > 0 && (ks)->t_exp > now) |
75 | |
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76 | /*----- Low-level packet encryption and decryption ------------------------*/ |
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77 | |
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78 | /* --- Encrypted data format --- * |
79 | * |
80 | * Let %$p_i$% be the %$i$%-th plaintext message. We first compute |
81 | * |
82 | * %$c_i = \mathcal{E}\textrm{-CBC}_{K_{\text{E}}}(p_i)$% |
83 | * |
84 | * as the CBC-ciphertext of %$p_i$%, and then |
85 | * |
86 | * %$\sigma_i = \mathcal{T}_{K_{\text{M}}}(i, c_i)$% |
87 | * |
88 | * as a MAC on the %%\emph{ciphertext}%%. The message sent is then the pair |
89 | * %$(\sigma_i, c_i)$%. This construction is provably secure in the NM-CCA |
90 | * sense (assuming that the cipher is IND-CPA, and the MAC is SUF-CMA) |
91 | * [Bellare and Namprempre]. |
92 | * |
93 | * This also ensures that, assuming the key is good, we have a secure channel |
94 | * [Krawczyk]. Actually, [Krawczyk] shows that, if the cipher is either a |
95 | * simple stream cipher or a block cipher in CBC mode, we can use the MAC- |
96 | * then-encrypt scheme and still have a secure channel. However, I like the |
97 | * NM-CCA guarantee from [Bellare and Namprempre]. I'm less worried about |
98 | * the Horton Principle [Wagner and Schneier]. |
99 | */ |
100 | |
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101 | /* --- @doencrypt@ --- * |
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102 | * |
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103 | * Arguments: @keyset *ks@ = pointer to keyset to use |
104 | * @buf *b@ = pointer to an input buffer |
105 | * @buf *bb@ = pointer to an output buffer |
410c8acf |
106 | * |
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107 | * Returns: Zero if OK, nonzero if a new key is required. |
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108 | * |
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109 | * Use: Encrypts a message with the given key. We assume that the |
110 | * keyset is OK to use. |
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111 | */ |
112 | |
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113 | static int doencrypt(keyset *ks, buf *b, buf *bb) |
410c8acf |
114 | { |
426c0bc6 |
115 | ghash *h; |
116 | gcipher *c; |
426c0bc6 |
117 | const octet *p = BCUR(b); |
118 | size_t sz = BLEFT(b); |
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119 | octet *qmac, *qseq, *qiv, *qpk; |
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120 | uint32 oseq; |
121 | size_t osz, nsz; |
122 | int rc = 0; |
123 | |
124 | /* --- Allocate the required buffer space --- */ |
125 | |
126 | c = ks->cout; |
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127 | if (buf_ensure(bb, MACSZ + SEQSZ + IVSZ + sz)) |
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128 | return (0); /* Caution! */ |
59d670e7 |
129 | qmac = BCUR(bb); qseq = qmac + MACSZ; qiv = qseq + SEQSZ; qpk = qiv + IVSZ; |
130 | BSTEP(bb, MACSZ + SEQSZ + IVSZ + sz); |
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131 | |
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132 | /* --- Encrypt the packet --- */ |
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133 | |
134 | oseq = ks->oseq++; STORE32(qseq, oseq); |
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135 | rand_get(RAND_GLOBAL, qiv, IVSZ); |
136 | c->ops->setiv(c, qiv); |
137 | c->ops->encrypt(c, p, qpk, sz); |
426c0bc6 |
138 | IF_TRACING(T_KEYSET, { |
139 | trace(T_KEYSET, "keyset: encrypting packet %lu using keyset %u", |
140 | (unsigned long)oseq, ks->seq); |
59d670e7 |
141 | trace_block(T_CRYPTO, "crypto: encrypted packet", qpk, sz); |
426c0bc6 |
142 | }) |
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143 | |
144 | /* --- Now compute the MAC --- */ |
145 | |
146 | h = ks->mout->ops->init(ks->mout); |
147 | h->ops->hash(h, qseq, SEQSZ + IVSZ + sz); |
148 | memcpy(qmac, h->ops->done(h, 0), MACSZ); |
149 | h->ops->destroy(h); |
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150 | IF_TRACING(T_KEYSET, { |
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151 | trace_block(T_CRYPTO, "crypto: computed MAC", qmac, MACSZ); |
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152 | }) |
153 | |
154 | /* --- Deduct the packet size from the key's data life --- */ |
155 | |
156 | osz = ks->sz_exp; |
157 | if (osz > sz) |
158 | nsz = osz - sz; |
159 | else |
160 | nsz = 0; |
161 | if (osz >= SZ_REGEN && nsz < SZ_REGEN) { |
162 | T( trace(T_KEYSET, "keyset: keyset %u data regen limit exceeded -- " |
163 | "forcing exchange", ks->seq); ) |
164 | rc = -1; |
165 | } |
166 | ks->sz_exp = nsz; |
167 | return (rc); |
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168 | } |
169 | |
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170 | /* --- @dodecrypt@ --- * |
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171 | * |
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172 | * Arguments: @keyset *ks@ = pointer to keyset to use |
173 | * @buf *b@ = pointer to an input buffer |
174 | * @buf *bb@ = pointer to an output buffer |
175 | * @uint32 *seq@ = where to store the sequence number |
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176 | * |
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177 | * Returns: Zero if OK, nonzero if it failed. |
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178 | * |
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179 | * Use: Attempts to decrypt a message with the given key. No other |
180 | * checking (e.g., sequence number checks) is performed. We |
181 | * assume that the keyset is OK to use, and that there is |
182 | * sufficient output buffer space reserved. If the decryption |
183 | * is successful, the buffer pointer is moved past the decrypted |
184 | * packet, and the packet's sequence number is stored in @*seq@. |
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185 | */ |
186 | |
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187 | static int dodecrypt(keyset *ks, buf *b, buf *bb, uint32 *seq) |
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188 | { |
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189 | const octet *pmac, *piv, *pseq, *ppk; |
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190 | size_t psz = BLEFT(b); |
191 | size_t sz; |
192 | octet *q = BCUR(bb); |
193 | ghash *h; |
194 | gcipher *c = ks->cin; |
195 | size_t ivsz = c->ops->c->blksz; |
196 | octet *mac; |
197 | int eq; |
198 | |
199 | /* --- Break up the packet into its components --- */ |
200 | |
201 | if (psz < ivsz + 4) { |
202 | T( trace(T_KEYSET, "keyset: block too small for keyset %u", ks->seq); ) |
203 | return (-1); |
410c8acf |
204 | } |
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205 | sz = psz - IVSZ - SEQSZ - MACSZ; |
206 | pmac = BCUR(b); pseq = pmac + MACSZ; piv = pseq + SEQSZ; ppk = piv + IVSZ; |
426c0bc6 |
207 | |
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208 | /* --- Verify the MAC on the packet --- */ |
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209 | |
426c0bc6 |
210 | h = ks->min->ops->init(ks->min); |
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211 | h->ops->hash(h, pseq, SEQSZ + IVSZ + sz); |
426c0bc6 |
212 | mac = h->ops->done(h, 0); |
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213 | eq = !memcmp(mac, pmac, MACSZ); |
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214 | IF_TRACING(T_KEYSET, { |
215 | trace(T_KEYSET, "keyset: decrypting using keyset %u", ks->seq); |
59d670e7 |
216 | trace_block(T_CRYPTO, "crypto: computed MAC", mac, MACSZ); |
426c0bc6 |
217 | }) |
218 | h->ops->destroy(h); |
219 | if (!eq) { |
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220 | a_warn("incorrect MAC on packet from `%s'", p_name(ks->p)); |
426c0bc6 |
221 | IF_TRACING(T_KEYSET, { |
222 | trace(T_KEYSET, "keyset: decryption failed"); |
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223 | trace_block(T_CRYPTO, "crypto: expected MAC", pmac, MACSZ); |
426c0bc6 |
224 | }) |
225 | return (-1); |
226 | } |
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227 | |
228 | /* --- Decrypt the packet --- */ |
229 | |
230 | c->ops->setiv(c, piv); |
231 | c->ops->decrypt(c, ppk, q, sz); |
426c0bc6 |
232 | if (seq) |
233 | *seq = LOAD32(pseq); |
234 | IF_TRACING(T_KEYSET, { |
235 | trace(T_KEYSET, "keyset: decrypted OK (sequence = %lu)", |
236 | (unsigned long)LOAD32(pseq)); |
237 | trace_block(T_CRYPTO, "crypto: decrypted packet", q, sz); |
238 | }) |
239 | BSTEP(bb, sz); |
240 | return (0); |
410c8acf |
241 | } |
242 | |
426c0bc6 |
243 | /* --- @dosequence@ --- * |
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244 | * |
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245 | * Arguments: @keyset *ks@ = pointer to a keyset |
246 | * @uint32 seq@ = a sequence number from a packet |
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247 | * |
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248 | * Returns: Zero if the sequence number is OK, nonzero if it's not. |
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249 | * |
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250 | * Use: Checks a sequence number. The data in the keyset which keeps |
251 | * track of valid sequence numbers is updated if the sequence |
252 | * number given is good. It's assumed that the sequence number |
253 | * has already been checked for authenticity. |
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254 | */ |
255 | |
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256 | static int dosequence(keyset *ks, uint32 seq) |
410c8acf |
257 | { |
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258 | uint32 seqbit; |
259 | uint32 n; |
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260 | |
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261 | if (seq < ks->iseq) { |
262 | a_warn("received packet has old sequence number (possible replay)"); |
263 | return (-1); |
410c8acf |
264 | } |
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265 | if (seq >= ks->iseq + KS_SEQWINSZ) { |
266 | n = seq - (ks->iseq + KS_SEQWINSZ - 1); |
267 | if (n < KS_SEQWINSZ) |
268 | ks->iwin >>= n; |
269 | else |
270 | ks->iwin = 0; |
271 | ks->iseq += n; |
272 | } |
273 | seqbit = 1 << (seq - ks->iseq); |
274 | if (ks->iwin & seqbit) { |
275 | a_warn("received packet repeats old sequence number"); |
276 | return (-1); |
277 | } |
278 | ks->iwin |= seqbit; |
279 | return (0); |
280 | } |
281 | |
282 | /*----- Operations on a single keyset -------------------------------------*/ |
283 | |
284 | /* --- @ks_drop@ --- * |
285 | * |
286 | * Arguments: @keyset *ks@ = pointer to a keyset |
287 | * |
288 | * Returns: --- |
289 | * |
290 | * Use: Decrements a keyset's reference counter. If the counter hits |
291 | * zero, the keyset is freed. |
292 | */ |
293 | |
294 | void ks_drop(keyset *ks) |
295 | { |
296 | if (--ks->ref) |
297 | return; |
298 | ks->cin->ops->destroy(ks->cin); |
299 | ks->cout->ops->destroy(ks->cout); |
300 | ks->min->ops->destroy(ks->min); |
301 | ks->mout->ops->destroy(ks->mout); |
302 | DESTROY(ks); |
410c8acf |
303 | } |
304 | |
305 | /* --- @ks_gen@ --- * |
306 | * |
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307 | * Arguments: @const void *k@ = pointer to key material |
308 | * @size_t x, y, z@ = offsets into key material (see below) |
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309 | * @peer *p@ = pointer to peer information |
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310 | * |
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311 | * Returns: A pointer to the new keyset. |
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312 | * |
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313 | * Use: Derives a new keyset from the given key material. The |
314 | * offsets @x@, @y@ and @z@ separate the key material into three |
315 | * parts. Between the @k@ and @k + x@ is `my' contribution to |
316 | * the key material; between @k + x@ and @k + y@ is `your' |
317 | * contribution; and between @k + y@ and @k + z@ is a shared |
318 | * value we made together. These are used to construct two |
319 | * pairs of symmetric keys. Each pair consists of an encryption |
320 | * key and a message authentication key. One pair is used for |
321 | * outgoing messages, the other for incoming messages. |
322 | * |
323 | * The new key is marked so that it won't be selected for output |
324 | * by @ksl_encrypt@. You can still encrypt data with it by |
325 | * calling @ks_encrypt@ directly. |
410c8acf |
326 | */ |
327 | |
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328 | keyset *ks_gen(const void *k, size_t x, size_t y, size_t z, peer *p) |
410c8acf |
329 | { |
426c0bc6 |
330 | HASH_CTX h; |
331 | octet buf[HASHSZ]; |
410c8acf |
332 | keyset *ks = CREATE(keyset); |
333 | time_t now = time(0); |
9466fafa |
334 | const octet *pp = k; |
410c8acf |
335 | T( static unsigned seq = 0; ) |
336 | |
337 | T( trace(T_KEYSET, "keyset: adding new keyset %u", seq); ) |
338 | |
426c0bc6 |
339 | /* --- Construct the various keys --- * |
340 | * |
341 | * This is done with macros, because it's quite tedious. |
342 | */ |
343 | |
9466fafa |
344 | #define MINE HASH(&h, pp, x) |
345 | #define YOURS HASH(&h, pp + x, y - x) |
346 | #define OURS HASH(&h, pp + y, z - y) |
426c0bc6 |
347 | |
348 | #define IN MINE; YOURS; OURS |
349 | #define OUT YOURS; MINE; OURS |
350 | #define STR_IN "incoming" |
351 | #define STR_OUT "outgoing" |
352 | |
353 | #define GETHASH(str, dir) do { \ |
354 | HASH_INIT(&h); \ |
355 | HASH_STRING(&h, "tripe-" str); \ |
356 | dir; \ |
357 | HASH_DONE(&h, buf); \ |
410c8acf |
358 | IF_TRACING(T_KEYSET, { \ |
426c0bc6 |
359 | trace_block(T_CRYPTO, "crypto: " STR_##dir " key " str, \ |
360 | buf, sizeof(buf)); \ |
410c8acf |
361 | }) \ |
362 | } while (0) |
363 | |
426c0bc6 |
364 | GETHASH("encryption", IN); ks->cin = CIPHER->init(buf, sizeof(buf)); |
365 | GETHASH("integrity", IN); ks->min = MAC->key(buf, sizeof(buf)); |
366 | GETHASH("encryption", OUT); ks->cout = CIPHER->init(buf, sizeof(buf)); |
367 | GETHASH("integrity", OUT); ks->mout = MAC->key(buf, sizeof(buf)); |
368 | |
369 | #undef MINE |
370 | #undef YOURS |
371 | #undef OURS |
372 | #undef IN |
373 | #undef OUT |
374 | #undef STR_IN |
375 | #undef STR_OUT |
410c8acf |
376 | #undef GETHASH |
377 | |
378 | T( ks->seq = seq++; ) |
426c0bc6 |
379 | ks->t_exp = now + T_EXP; |
380 | ks->sz_exp = SZ_EXP; |
09585a65 |
381 | ks->oseq = ks->iseq = 0; |
382 | ks->iwin = 0; |
426c0bc6 |
383 | ks->next = 0; |
9466fafa |
384 | ks->p = p; |
426c0bc6 |
385 | ks->f = KSF_LISTEN; |
410c8acf |
386 | BURN(buf); |
426c0bc6 |
387 | return (ks); |
388 | } |
389 | |
390 | /* --- @ks_tregen@ --- * |
391 | * |
392 | * Arguments: @keyset *ks@ = pointer to a keyset |
393 | * |
394 | * Returns: The time at which moves ought to be made to replace this key. |
395 | */ |
396 | |
397 | time_t ks_tregen(keyset *ks) { return (ks->t_exp - T_EXP + T_REGEN); } |
398 | |
399 | /* --- @ks_activate@ --- * |
400 | * |
401 | * Arguments: @keyset *ks@ = pointer to a keyset |
402 | * |
403 | * Returns: --- |
404 | * |
405 | * Use: Activates a keyset, so that it can be used for encrypting |
406 | * outgoing messages. |
407 | */ |
408 | |
409 | void ks_activate(keyset *ks) |
410 | { |
411 | if (ks->f & KSF_LISTEN) { |
412 | T( trace(T_KEYSET, "keyset: activating keyset %u", ks->seq); ) |
413 | ks->f &= ~KSF_LISTEN; |
414 | } |
410c8acf |
415 | } |
416 | |
417 | /* --- @ks_encrypt@ --- * |
426c0bc6 |
418 | * |
419 | * Arguments: @keyset *ks@ = pointer to a keyset |
420 | * @buf *b@ = pointer to input buffer |
421 | * @buf *bb@ = pointer to output buffer |
422 | * |
423 | * Returns: Zero if OK, nonzero if the key needs replacing. If the |
424 | * encryption failed, the output buffer is broken and zero is |
425 | * returned. |
426 | * |
427 | * Use: Encrypts a block of data using the key. Note that the `key |
428 | * ought to be replaced' notification is only ever given once |
429 | * for each key. Also note that this call forces a keyset to be |
430 | * used even if it's marked as not for data output. |
431 | */ |
432 | |
433 | int ks_encrypt(keyset *ks, buf *b, buf *bb) |
434 | { |
435 | time_t now = time(0); |
436 | |
437 | if (!KEYOK(ks, now)) { |
438 | buf_break(bb); |
439 | return (0); |
440 | } |
441 | return (doencrypt(ks, b, bb)); |
442 | } |
443 | |
444 | /* --- @ks_decrypt@ --- * |
445 | * |
446 | * Arguments: @keyset *ks@ = pointer to a keyset |
447 | * @buf *b@ = pointer to an input buffer |
448 | * @buf *bb@ = pointer to an output buffer |
449 | * |
450 | * Returns: Zero on success, or nonzero if there was some problem. |
451 | * |
452 | * Use: Attempts to decrypt a message using a given key. Note that |
453 | * requesting decryption with a key directly won't clear a |
454 | * marking that it's not for encryption. |
455 | */ |
456 | |
457 | int ks_decrypt(keyset *ks, buf *b, buf *bb) |
458 | { |
459 | time_t now = time(0); |
460 | uint32 seq; |
461 | |
462 | if (!KEYOK(ks, now) || |
463 | buf_ensure(bb, BLEN(b)) || |
464 | dodecrypt(ks, b, bb, &seq) || |
465 | dosequence(ks, seq)) |
466 | return (-1); |
467 | return (0); |
468 | } |
469 | |
470 | /*----- Keyset list handling ----------------------------------------------*/ |
471 | |
472 | /* --- @ksl_free@ --- * |
473 | * |
474 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
475 | * |
476 | * Returns: --- |
477 | * |
478 | * Use: Frees (releases references to) all of the keys in a keyset. |
479 | */ |
480 | |
481 | void ksl_free(keyset **ksroot) |
482 | { |
483 | keyset *ks, *ksn; |
484 | for (ks = *ksroot; ks; ks = ksn) { |
485 | ksn = ks->next; |
486 | ks->f &= ~KSF_LINK; |
487 | ks_drop(ks); |
488 | } |
489 | } |
490 | |
491 | /* --- @ksl_link@ --- * |
492 | * |
493 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
494 | * @keyset *ks@ = pointer to a keyset |
495 | * |
496 | * Returns: --- |
497 | * |
498 | * Use: Links a keyset into a list. A keyset can only be on one list |
499 | * at a time. Bad things happen otherwise. |
500 | */ |
501 | |
502 | void ksl_link(keyset **ksroot, keyset *ks) |
503 | { |
504 | assert(!(ks->f & KSF_LINK)); |
505 | ks->next = *ksroot; |
506 | *ksroot = ks; |
507 | ks->f |= KSF_LINK; |
508 | ks->ref++; |
509 | } |
510 | |
511 | /* --- @ksl_prune@ --- * |
512 | * |
513 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
514 | * |
515 | * Returns: --- |
516 | * |
517 | * Use: Prunes the keyset list by removing keys which mustn't be used |
518 | * any more. |
519 | */ |
520 | |
521 | void ksl_prune(keyset **ksroot) |
522 | { |
523 | time_t now = time(0); |
524 | |
525 | while (*ksroot) { |
526 | keyset *ks = *ksroot; |
527 | |
528 | if (ks->t_exp <= now) { |
529 | T( trace(T_KEYSET, "keyset: expiring keyset %u (time limit reached)", |
530 | ks->seq); ) |
531 | goto kill; |
532 | } else if (ks->sz_exp == 0) { |
533 | T( trace(T_KEYSET, "keyset: expiring keyset %u (data limit reached)", |
534 | ks->seq); ) |
535 | goto kill; |
536 | } else { |
537 | ksroot = &ks->next; |
538 | continue; |
539 | } |
540 | |
541 | kill: |
542 | *ksroot = ks->next; |
543 | ks->f &= ~KSF_LINK; |
544 | ks_drop(ks); |
545 | } |
546 | } |
547 | |
548 | /* --- @ksl_encrypt@ --- * |
410c8acf |
549 | * |
550 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
551 | * @buf *b@ = pointer to input buffer |
552 | * @buf *bb@ = pointer to output buffer |
553 | * |
554 | * Returns: Nonzero if a new key is needed. |
555 | * |
556 | * Use: Encrypts a packet. |
557 | */ |
558 | |
426c0bc6 |
559 | int ksl_encrypt(keyset **ksroot, buf *b, buf *bb) |
410c8acf |
560 | { |
561 | time_t now = time(0); |
426c0bc6 |
562 | keyset *ks = *ksroot; |
410c8acf |
563 | |
410c8acf |
564 | for (;;) { |
565 | if (!ks) { |
426c0bc6 |
566 | T( trace(T_KEYSET, "keyset: no suitable keysets found"); ) |
410c8acf |
567 | buf_break(bb); |
568 | return (-1); |
569 | } |
426c0bc6 |
570 | if (KEYOK(ks, now) && !(ks->f & KSF_LISTEN)) |
410c8acf |
571 | break; |
572 | ks = ks->next; |
573 | } |
574 | |
426c0bc6 |
575 | return (doencrypt(ks, b, bb)); |
410c8acf |
576 | } |
577 | |
426c0bc6 |
578 | /* --- @ksl_decrypt@ --- * |
410c8acf |
579 | * |
580 | * Arguments: @keyset **ksroot@ = pointer to keyset list head |
581 | * @buf *b@ = pointer to input buffer |
582 | * @buf *bb@ = pointer to output buffer |
583 | * |
584 | * Returns: Nonzero if the packet couldn't be decrypted. |
585 | * |
586 | * Use: Decrypts a packet. |
587 | */ |
588 | |
426c0bc6 |
589 | int ksl_decrypt(keyset **ksroot, buf *b, buf *bb) |
410c8acf |
590 | { |
591 | time_t now = time(0); |
410c8acf |
592 | keyset *ks; |
426c0bc6 |
593 | uint32 seq; |
410c8acf |
594 | |
426c0bc6 |
595 | if (buf_ensure(bb, BLEN(b))) |
410c8acf |
596 | return (-1); |
09585a65 |
597 | |
410c8acf |
598 | for (ks = *ksroot; ks; ks = ks->next) { |
410c8acf |
599 | if (!KEYOK(ks, now)) |
600 | continue; |
426c0bc6 |
601 | if (!dodecrypt(ks, b, bb, &seq)) { |
602 | if (ks->f & KSF_LISTEN) { |
603 | T( trace(T_KEYSET, "keyset: implicitly activating keyset %u", |
604 | ks->seq); ) |
605 | ks->f &= ~KSF_LISTEN; |
606 | } |
607 | return (dosequence(ks, seq)); |
410c8acf |
608 | } |
410c8acf |
609 | } |
610 | T( trace(T_KEYSET, "keyset: no matching keys"); ) |
611 | return (-1); |
612 | } |
613 | |
614 | /*----- That's all, folks -------------------------------------------------*/ |