Commit | Line | Data |
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79ba130c | 1 | /* -*-c-*- |
79ba130c | 2 | * |
3 | * Definitions for cipher block chaining mode | |
4 | * | |
5 | * (c) 1999 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
79ba130c | 9 | * |
10 | * This file is part of Catacomb. | |
11 | * | |
12 | * Catacomb is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
45c0fd36 | 16 | * |
79ba130c | 17 | * Catacomb 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 Library General Public License for more details. | |
45c0fd36 | 21 | * |
79ba130c | 22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
79ba130c | 28 | #ifndef CATACOMB_CBC_DEF_H |
29 | #define CATACOMB_CBC_DEF_H | |
30 | ||
31 | #ifdef __cplusplus | |
32 | extern "C" { | |
33 | #endif | |
34 | ||
35 | /*----- Header files ------------------------------------------------------*/ | |
36 | ||
37 | #include <string.h> | |
38 | ||
39 | #include <mLib/bits.h> | |
40 | #include <mLib/sub.h> | |
41 | ||
99461409 | 42 | #ifndef CATACOMB_ARENA_H |
43 | # include "arena.h" | |
44 | #endif | |
45 | ||
79ba130c | 46 | #ifndef CATACOMB_BLKC_H |
47 | # include "blkc.h" | |
48 | #endif | |
49 | ||
50 | #ifndef CATACOMB_GCIPHER_H | |
51 | # include "gcipher.h" | |
52 | #endif | |
53 | ||
99461409 | 54 | #ifndef CATACOMB_PARANOIA_H |
55 | # include "paranoia.h" | |
56 | #endif | |
57 | ||
79ba130c | 58 | /*----- Macros ------------------------------------------------------------*/ |
59 | ||
60 | /* --- @CBC_DEF@ --- * | |
61 | * | |
62 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher | |
63 | * | |
64 | * Use: Creates an implementation for CBC stealing mode. | |
65 | */ | |
66 | ||
aaae9cab MW |
67 | #define CBC_DEF(PRE, pre) CBC_DEFX(PRE, pre, #pre, #pre) |
68 | ||
69 | #define CBC_DEFX(PRE, pre, name, fname) \ | |
79ba130c | 70 | \ |
71 | /* --- @pre_cbcgetiv@ --- * \ | |
72 | * \ | |
73 | * Arguments: @const pre_cbcctx *ctx@ = pointer to CBC context block \ | |
4efe32ba | 74 | * @void *iv@ = pointer to output data block \ |
79ba130c | 75 | * \ |
76 | * Returns: --- \ | |
77 | * \ | |
78 | * Use: Reads the currently set IV. Reading and setting an IV \ | |
79 | * is transparent to the CBC encryption or decryption \ | |
80 | * process. \ | |
81 | */ \ | |
82 | \ | |
83 | void pre##_cbcgetiv(const pre##_cbcctx *ctx, void *iv) \ | |
0fee61eb | 84 | { BLKC_STORE(PRE, iv, ctx->a); } \ |
79ba130c | 85 | \ |
86 | /* --- @pre_cbcsetiv@ --- * \ | |
87 | * \ | |
88 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ | |
89 | * @cnost void *iv@ = pointer to IV to set \ | |
90 | * \ | |
91 | * Returns: --- \ | |
92 | * \ | |
93 | * Use: Sets the IV to use for subsequent encryption. \ | |
94 | */ \ | |
95 | \ | |
96 | void pre##_cbcsetiv(pre##_cbcctx *ctx, const void *iv) \ | |
0fee61eb | 97 | { BLKC_LOAD(PRE, ctx->a, iv); } \ |
79ba130c | 98 | \ |
99 | /* --- @pre_cbcsetkey@ --- * \ | |
100 | * \ | |
101 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ | |
102 | * @const pre_ctx *k@ = pointer to cipher context \ | |
103 | * \ | |
104 | * Returns: --- \ | |
105 | * \ | |
106 | * Use: Sets the CBC context to use a different cipher key. \ | |
107 | */ \ | |
108 | \ | |
109 | void pre##_cbcsetkey(pre##_cbcctx *ctx, const pre##_ctx *k) \ | |
0fee61eb | 110 | { ctx->ctx = *k; } \ |
79ba130c | 111 | \ |
112 | /* --- @pre_cbcinit@ --- * \ | |
113 | * \ | |
114 | * Arguments: @pre_cbcctx *ctx@ = pointer to cipher context \ | |
115 | * @const void *key@ = pointer to the key buffer \ | |
116 | * @size_t sz@ = size of the key \ | |
117 | * @const void *iv@ = pointer to initialization vector \ | |
118 | * \ | |
119 | * Returns: --- \ | |
120 | * \ | |
121 | * Use: Initializes a CBC context ready for use. The @iv@ \ | |
122 | * argument may be passed as a null pointer to set a zero \ | |
123 | * IV. Apart from that, this call is equivalent to calls \ | |
124 | * to @pre_init@, @pre_cbcsetkey@ and @pre_cbcsetiv@. \ | |
125 | */ \ | |
126 | \ | |
127 | void pre##_cbcinit(pre##_cbcctx *ctx, \ | |
81b52866 MW |
128 | const void *key, size_t sz, \ |
129 | const void *iv) \ | |
79ba130c | 130 | { \ |
4e66da02 | 131 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
0fee61eb | 132 | \ |
79ba130c | 133 | pre##_init(&ctx->ctx, key, sz); \ |
0fee61eb | 134 | BLKC_LOAD(PRE, ctx->a, iv ? iv : zero); \ |
79ba130c | 135 | } \ |
136 | \ | |
137 | /* --- @pre_cbcencrypt@ --- * \ | |
138 | * \ | |
139 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ | |
140 | * @const void *src@ = pointer to source data \ | |
141 | * @void *dest@ = pointer to destination data \ | |
142 | * @size_t sz@ = size of block to be encrypted \ | |
143 | * \ | |
144 | * Returns: --- \ | |
145 | * \ | |
146 | * Use: Encrypts a block with a block cipher in CBC mode, with \ | |
147 | * ciphertext stealing and other clever tricks. \ | |
148 | * Essentially, data can be encrypted in arbitrary sized \ | |
149 | * chunks, although decryption must use the same chunks. \ | |
150 | */ \ | |
151 | \ | |
152 | void pre##_cbcencrypt(pre##_cbcctx *ctx, \ | |
81b52866 MW |
153 | const void *src, void *dest, \ |
154 | size_t sz) \ | |
79ba130c | 155 | { \ |
156 | const octet *s = src; \ | |
157 | octet *d = dest; \ | |
460bbf88 | 158 | octet b[PRE##_BLKSZ], bb[PRE##_BLKSZ]; \ |
0fee61eb MW |
159 | octet y; \ |
160 | unsigned i; \ | |
79ba130c | 161 | \ |
162 | /* --- Empty blocks are trivial --- */ \ | |
163 | \ | |
0fee61eb | 164 | if (!sz) return; \ |
79ba130c | 165 | \ |
166 | /* --- Extra magical case for a short block --- * \ | |
167 | * \ | |
168 | * Encrypt the IV, then exclusive-or the plaintext with the octets \ | |
169 | * of the encrypted IV, shifting ciphertext octets in instead. This \ | |
170 | * basically switches over to CFB. \ | |
171 | */ \ | |
172 | \ | |
173 | if (sz < PRE##_BLKSZ) { \ | |
0fee61eb MW |
174 | pre##_eblk(&ctx->ctx, ctx->a, ctx->a); \ |
175 | BLKC_STORE(PRE, b, ctx->a); \ | |
460bbf88 MW |
176 | if (!d) d = bb; \ |
177 | for (i = 0; i < sz; i++) d[i] = b[i] ^ (s ? s[i] : 0); \ | |
79ba130c | 178 | memmove(b, b + sz, PRE##_BLKSZ - sz); \ |
179 | memcpy(b + PRE##_BLKSZ - sz, d, sz); \ | |
0fee61eb | 180 | BLKC_LOAD(PRE, ctx->a, b); \ |
79ba130c | 181 | return; \ |
182 | } \ | |
183 | \ | |
184 | /* --- Do the main chunk of encryption --- * \ | |
185 | * \ | |
186 | * This will do the whole lot if it's a whole number of blocks. For \ | |
187 | * each block, XOR it with the previous ciphertext in @iv@, encrypt, \ | |
188 | * and keep a copy of the ciphertext for the next block. \ | |
189 | */ \ | |
190 | \ | |
0fee61eb MW |
191 | while (sz >= 2*PRE##_BLKSZ || sz == PRE##_BLKSZ) { \ |
192 | if (s) { BLKC_XLOAD(PRE, ctx->a, s); s += PRE##_BLKSZ; } \ | |
193 | pre##_eblk(&ctx->ctx, ctx->a, ctx->a); \ | |
194 | if (d) { BLKC_STORE(PRE, d, ctx->a); d += PRE##_BLKSZ; } \ | |
79ba130c | 195 | sz -= PRE##_BLKSZ; \ |
196 | } \ | |
197 | \ | |
198 | /* --- Do the tail-end block and bit-left-over --- * \ | |
199 | * \ | |
200 | * This isn't very efficient. That shouldn't matter much. \ | |
201 | */ \ | |
202 | \ | |
203 | if (sz) { \ | |
79ba130c | 204 | \ |
205 | /* --- Let @sz@ be the size of the partial block --- */ \ | |
206 | \ | |
207 | sz -= PRE##_BLKSZ; \ | |
208 | \ | |
209 | /* --- First stage --- * \ | |
210 | * \ | |
211 | * XOR the complete block with the current IV, and encrypt it. The \ | |
212 | * first part of the result is the partial ciphertext block. Don't \ | |
213 | * write that out yet, because I've not read the partial plaintext \ | |
214 | * block. \ | |
215 | */ \ | |
216 | \ | |
0fee61eb MW |
217 | if (s) BLKC_XLOAD(PRE, ctx->a, s); \ |
218 | pre##_eblk(&ctx->ctx, ctx->a, ctx->a); \ | |
219 | BLKC_STORE(PRE, b, ctx->a); \ | |
79ba130c | 220 | \ |
221 | /* --- Second stage --- * \ | |
222 | * \ | |
223 | * Now XOR in the partial plaintext block, writing out the \ | |
224 | * ciphertext as I go. Then encrypt, and write the complete \ | |
225 | * ciphertext block. \ | |
226 | */ \ | |
227 | \ | |
5c3f75ec | 228 | if (s) s += PRE##_BLKSZ; \ |
229 | if (d) d += PRE##_BLKSZ; \ | |
79ba130c | 230 | for (i = 0; i < sz; i++) { \ |
0fee61eb | 231 | y = b[i]; \ |
5c3f75ec | 232 | if (s) b[i] ^= s[i]; \ |
0fee61eb | 233 | if (d) d[i] = y; \ |
79ba130c | 234 | } \ |
0fee61eb MW |
235 | BLKC_LOAD(PRE, ctx->a, b); \ |
236 | pre##_eblk(&ctx->ctx, ctx->a, ctx->a); \ | |
237 | if (d) BLKC_STORE(PRE, d - PRE##_BLKSZ, ctx->a); \ | |
79ba130c | 238 | } \ |
239 | \ | |
240 | /* --- Done --- */ \ | |
241 | \ | |
242 | return; \ | |
243 | } \ | |
244 | \ | |
245 | /* --- @pre_cbcdecrypt@ --- * \ | |
246 | * \ | |
247 | * Arguments: @pre_cbcctx *ctx@ = pointer to CBC context block \ | |
248 | * @const void *src@ = pointer to source data \ | |
249 | * @void *dest@ = pointer to destination data \ | |
250 | * @size_t sz@ = size of block to be encrypted \ | |
251 | * \ | |
252 | * Returns: --- \ | |
253 | * \ | |
254 | * Use: Decrypts a block with a block cipher in CBC mode, with \ | |
255 | * ciphertext stealing and other clever tricks. \ | |
256 | * Essentially, data can be encrypted in arbitrary sized \ | |
257 | * chunks, although decryption must use the same chunks. \ | |
258 | */ \ | |
259 | \ | |
260 | void pre##_cbcdecrypt(pre##_cbcctx *ctx, \ | |
81b52866 MW |
261 | const void *src, void *dest, \ |
262 | size_t sz) \ | |
79ba130c | 263 | { \ |
264 | const octet *s = src; \ | |
265 | octet *d = dest; \ | |
0fee61eb MW |
266 | uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4]; \ |
267 | octet b[PRE##_BLKSZ], c[PRE##_BLKSZ]; \ | |
268 | octet y; \ | |
269 | unsigned i; \ | |
79ba130c | 270 | \ |
271 | /* --- Empty blocks are trivial --- */ \ | |
272 | \ | |
0fee61eb | 273 | if (!sz) return; \ |
79ba130c | 274 | \ |
275 | /* --- Extra magical case for a short block --- * \ | |
276 | * \ | |
277 | * Encrypt the IV, then exclusive-or the ciphertext with the octets \ | |
278 | * of the encrypted IV, shifting ciphertext octets in instead. This \ | |
279 | * basically switches over to CFB. \ | |
280 | */ \ | |
281 | \ | |
282 | if (sz < PRE##_BLKSZ) { \ | |
0fee61eb MW |
283 | pre##_eblk(&ctx->ctx, ctx->a, ctx->a); \ |
284 | BLKC_STORE(PRE, b, ctx->a); \ | |
285 | for (i = 0; i < sz; i++) { y = s[i]; d[i] = b[i] ^ y; c[i] = y; } \ | |
79ba130c | 286 | memmove(b, b + sz, PRE##_BLKSZ - sz); \ |
287 | memcpy(b + PRE##_BLKSZ - sz, c, sz); \ | |
0fee61eb | 288 | BLKC_LOAD(PRE, ctx->a, b); \ |
79ba130c | 289 | return; \ |
290 | } \ | |
291 | \ | |
292 | /* --- Do the main chunk of decryption --- * \ | |
293 | * \ | |
294 | * This will do the whole lot if it's a whole number of blocks. For \ | |
295 | * each block, decrypt, XOR it with the previous ciphertext in @iv@, \ | |
296 | * and keep a copy of the ciphertext for the next block. \ | |
297 | */ \ | |
298 | \ | |
0fee61eb MW |
299 | while (sz >= 2*PRE##_BLKSZ || sz == PRE##_BLKSZ) { \ |
300 | BLKC_LOAD(PRE, t, s); s += PRE##_BLKSZ; \ | |
301 | pre##_dblk(&ctx->ctx, t, u); \ | |
302 | BLKC_XSTORE(PRE, d, u, ctx->a); d += PRE##_BLKSZ; \ | |
303 | BLKC_MOVE(PRE, ctx->a, t); \ | |
79ba130c | 304 | sz -= PRE##_BLKSZ; \ |
305 | } \ | |
306 | \ | |
307 | /* --- Do the tail-end block and bit-left-over --- * \ | |
308 | * \ | |
309 | * This isn't very efficient. That shouldn't matter much. \ | |
310 | */ \ | |
311 | \ | |
312 | if (sz) { \ | |
79ba130c | 313 | \ |
314 | /* --- Let @sz@ be the size of the partial block --- */ \ | |
315 | \ | |
316 | sz -= PRE##_BLKSZ; \ | |
317 | \ | |
318 | /* --- First stage --- * \ | |
319 | * \ | |
320 | * Take the complete ciphertext block, and decrypt it. This block \ | |
321 | * is carried over for the next encryption operation. \ | |
322 | */ \ | |
323 | \ | |
0fee61eb MW |
324 | BLKC_LOAD(PRE, t, s); \ |
325 | pre##_dblk(&ctx->ctx, t, u); \ | |
79ba130c | 326 | \ |
327 | /* --- Second stage --- * \ | |
328 | * \ | |
329 | * XORing the first few bytes of this with the partial ciphertext \ | |
330 | * block recovers the partial plaintext block. At the same time, \ | |
331 | * write the partial ciphertext block's contents in ready for stage \ | |
332 | * three. \ | |
333 | */ \ | |
334 | \ | |
0fee61eb | 335 | BLKC_STORE(PRE, b, u); \ |
79ba130c | 336 | s += PRE##_BLKSZ; \ |
337 | d += PRE##_BLKSZ; \ | |
0fee61eb | 338 | for (i = 0; i < sz; i++) { y = s[i]; d[i] = b[i] ^ y; b[i] = y; } \ |
79ba130c | 339 | \ |
340 | /* --- Third stage --- * \ | |
341 | * \ | |
342 | * Decrypt the block we've got left, and XOR with the initial IV to \ | |
343 | * recover the complete plaintext block. \ | |
344 | */ \ | |
345 | \ | |
0fee61eb MW |
346 | BLKC_LOAD(PRE, u, b); \ |
347 | pre##_dblk(&ctx->ctx, u, u); \ | |
348 | BLKC_XSTORE(PRE, d - PRE##_BLKSZ, u, ctx->a); \ | |
349 | BLKC_MOVE(PRE, ctx->a, t); \ | |
79ba130c | 350 | } \ |
351 | \ | |
352 | /* --- Done --- */ \ | |
353 | \ | |
354 | return; \ | |
355 | } \ | |
356 | \ | |
357 | /* --- Generic cipher interface --- */ \ | |
358 | \ | |
359 | static const gcipher_ops gops; \ | |
360 | \ | |
361 | typedef struct gctx { \ | |
362 | gcipher c; \ | |
363 | pre##_cbcctx k; \ | |
364 | } gctx; \ | |
365 | \ | |
366 | static gcipher *ginit(const void *k, size_t sz) \ | |
367 | { \ | |
99461409 | 368 | gctx *g = S_CREATE(gctx); \ |
79ba130c | 369 | g->c.ops = &gops; \ |
370 | pre##_cbcinit(&g->k, k, sz, 0); \ | |
371 | return (&g->c); \ | |
372 | } \ | |
373 | \ | |
374 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ | |
0fee61eb | 375 | { gctx *g = (gctx *)c; pre##_cbcencrypt(&g->k, s, t, sz); } \ |
79ba130c | 376 | \ |
377 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ | |
0fee61eb | 378 | { gctx *g = (gctx *)c; pre##_cbcdecrypt(&g->k, s, t, sz); } \ |
79ba130c | 379 | \ |
380 | static void gdestroy(gcipher *c) \ | |
0fee61eb | 381 | { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); } \ |
79ba130c | 382 | \ |
383 | static void gsetiv(gcipher *c, const void *iv) \ | |
0fee61eb | 384 | { gctx *g = (gctx *)c; pre##_cbcsetiv(&g->k, iv); } \ |
79ba130c | 385 | \ |
386 | static const gcipher_ops gops = { \ | |
99461409 | 387 | &pre##_cbc, \ |
388 | gencrypt, gdecrypt, gdestroy, gsetiv, 0 \ | |
79ba130c | 389 | }; \ |
390 | \ | |
391 | const gccipher pre##_cbc = { \ | |
aaae9cab | 392 | name "-cbc", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c | 393 | ginit \ |
394 | }; \ | |
395 | \ | |
aaae9cab | 396 | CBC_TESTX(PRE, pre, name, fname) |
79ba130c | 397 | |
398 | /*----- Test rig ----------------------------------------------------------*/ | |
399 | ||
aaae9cab MW |
400 | #define CBC_TEST(PRE, pre) CBC_TESTX(PRE, pre, #pre, #pre) |
401 | ||
79ba130c | 402 | #ifdef TEST_RIG |
403 | ||
57f459eb | 404 | #include "modes-test.h" |
79ba130c | 405 | |
406 | /* --- @CBC_TEST@ --- * | |
407 | * | |
408 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions | |
409 | * | |
410 | * Use: Standard test rig for CBC functions. | |
411 | */ | |
412 | ||
aaae9cab | 413 | #define CBC_TESTX(PRE, pre, name, fname) \ |
79ba130c | 414 | \ |
57f459eb MW |
415 | static pre##_ctx key; \ |
416 | static pre##_cbcctx ctx; \ | |
79ba130c | 417 | \ |
57f459eb MW |
418 | static void pre##_cbc_test_setup(const octet *k, size_t ksz) \ |
419 | { pre##_init(&key, k, ksz); pre##_cbcsetkey(&ctx, &key); } \ | |
79ba130c | 420 | \ |
57f459eb MW |
421 | static void pre##_cbc_test_reset(const octet *iv) \ |
422 | { pre##_cbcsetiv(&ctx, iv); } \ | |
79ba130c | 423 | \ |
57f459eb MW |
424 | static void pre##_cbc_test_enc(const octet *s, octet *d, size_t sz) \ |
425 | { pre##_cbcencrypt(&ctx, s, d, sz); } \ | |
79ba130c | 426 | \ |
57f459eb MW |
427 | static void pre##_cbc_test_dec(const octet *s, octet *d, size_t sz) \ |
428 | { pre##_cbcdecrypt(&ctx, s, d, sz); } \ | |
79ba130c | 429 | \ |
57f459eb | 430 | int main(int argc, char *argv[]) \ |
79ba130c | 431 | { \ |
57f459eb MW |
432 | return test_encmode(fname "-cbc", PRE##_KEYSZ, PRE##_BLKSZ, \ |
433 | 1, TEMF_REFALIGN, \ | |
434 | pre##_cbc_test_setup, pre##_cbc_test_reset, \ | |
435 | pre##_cbc_test_enc, pre##_cbc_test_dec, \ | |
436 | argc, argv); \ | |
79ba130c | 437 | } |
438 | ||
439 | #else | |
aaae9cab | 440 | # define CBC_TESTX(PRE, pre, name, fname) |
79ba130c | 441 | #endif |
442 | ||
443 | /*----- That's all, folks -------------------------------------------------*/ | |
444 | ||
445 | #ifdef __cplusplus | |
446 | } | |
447 | #endif | |
448 | ||
449 | #endif |