Commit | Line | Data |
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79ba130c | 1 | /* -*-c-*- |
79ba130c | 2 | * |
3 | * Definitions for ciphertext feedback 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_CFB_DEF_H |
29 | #define CATACOMB_CFB_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 | ||
426aab6b | 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 | ||
54 | #ifndef CATACOMB_PARANOIA_H | |
55 | # include "paranoia.h" | |
56 | #endif | |
57 | ||
426aab6b | 58 | #ifndef CATACOMB_PARANOIA_H |
59 | # include "paranoia.h" | |
60 | #endif | |
61 | ||
79ba130c | 62 | /*----- Macros ------------------------------------------------------------*/ |
63 | ||
64 | /* --- @CFB_DEF@ --- * | |
65 | * | |
66 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher | |
67 | * | |
68 | * Use: Creates an implementation for CFB mode. | |
69 | */ | |
70 | ||
71 | #define CFB_DEF(PRE, pre) \ | |
72 | \ | |
73 | /* --- @pre_cfbgetiv@ --- * \ | |
74 | * \ | |
75 | * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \ | |
4efe32ba | 76 | * @void *iv@ = pointer to output data block \ |
79ba130c | 77 | * \ |
78 | * Returns: --- \ | |
79 | * \ | |
80 | * Use: Reads the currently set IV. Reading and setting an IV \ | |
81 | * is not transparent to the cipher. It will add a `step' \ | |
82 | * which must be matched by a similar operation during \ | |
83 | * decryption. \ | |
84 | */ \ | |
85 | \ | |
86 | void pre##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \ | |
87 | { \ | |
88 | octet *p = iv; \ | |
426aab6b | 89 | unsigned off = ctx->off; \ |
90 | unsigned rest = PRE##_BLKSZ - off; \ | |
79ba130c | 91 | memcpy(p, ctx->iv + off, rest); \ |
92 | memcpy(p + rest, ctx->iv, off); \ | |
93 | } \ | |
94 | \ | |
95 | /* --- @pre_cfbsetiv@ --- * \ | |
96 | * \ | |
97 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ | |
98 | * @cnost void *iv@ = pointer to IV to set \ | |
99 | * \ | |
100 | * Returns: --- \ | |
101 | * \ | |
102 | * Use: Sets the IV to use for subsequent encryption. \ | |
103 | */ \ | |
104 | \ | |
105 | void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \ | |
106 | { \ | |
426aab6b | 107 | memcpy(ctx->iv, iv, PRE##_BLKSZ); \ |
108 | ctx->off = PRE##_BLKSZ; \ | |
79ba130c | 109 | } \ |
110 | \ | |
111 | /* --- @pre_cfbbdry@ --- * \ | |
112 | * \ | |
113 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ | |
114 | * \ | |
115 | * Returns: --- \ | |
116 | * \ | |
117 | * Use: Inserts a boundary during encryption. Successful \ | |
118 | * decryption must place a similar boundary. \ | |
119 | */ \ | |
120 | \ | |
121 | void pre##_cfbbdry(pre##_cfbctx *ctx) \ | |
122 | { \ | |
426aab6b | 123 | uint32 niv[PRE##_BLKSZ / 4]; \ |
124 | BLKC_LOAD(PRE, niv, ctx->iv); \ | |
125 | pre##_eblk(&ctx->ctx, niv, niv); \ | |
126 | BLKC_STORE(PRE, ctx->iv, niv); \ | |
127 | ctx->off = PRE##_BLKSZ; \ | |
128 | BURN(niv); \ | |
79ba130c | 129 | } \ |
130 | \ | |
131 | /* --- @pre_cfbsetkey@ --- * \ | |
132 | * \ | |
133 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ | |
134 | * @const pre_ctx *k@ = pointer to cipher context \ | |
135 | * \ | |
136 | * Returns: --- \ | |
137 | * \ | |
138 | * Use: Sets the CFB context to use a different cipher key. \ | |
139 | */ \ | |
140 | \ | |
141 | void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \ | |
142 | { \ | |
143 | ctx->ctx = *k; \ | |
426aab6b | 144 | ctx->off = PRE##_BLKSZ; \ |
79ba130c | 145 | } \ |
146 | \ | |
147 | /* --- @pre_cfbinit@ --- * \ | |
148 | * \ | |
149 | * Arguments: @pre_cfbctx *ctx@ = pointer to cipher context \ | |
150 | * @const void *key@ = pointer to the key buffer \ | |
151 | * @size_t sz@ = size of the key \ | |
152 | * @const void *iv@ = pointer to initialization vector \ | |
153 | * \ | |
154 | * Returns: --- \ | |
155 | * \ | |
156 | * Use: Initializes a CFB context ready for use. You should \ | |
157 | * ensure that the IV chosen is unique: reusing an IV will \ | |
158 | * compromise the security of at least the first block \ | |
159 | * encrypted. This is equivalent to calls to @pre_init@, \ | |
160 | * @pre_cfbsetkey@ and @pre_cfbsetiv@. \ | |
161 | */ \ | |
162 | \ | |
163 | void pre##_cfbinit(pre##_cfbctx *ctx, \ | |
164 | const void *key, size_t sz, \ | |
165 | const void *iv) \ | |
166 | { \ | |
4e66da02 | 167 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
79ba130c | 168 | pre##_init(&ctx->ctx, key, sz); \ |
169 | pre##_cfbsetiv(ctx, iv ? iv : zero); \ | |
170 | } \ | |
171 | \ | |
172 | /* --- @pre_cfbencrypt@ --- * \ | |
173 | * \ | |
174 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ | |
175 | * @const void *src@ = pointer to source data \ | |
176 | * @void *dest@ = pointer to destination data \ | |
177 | * @size_t sz@ = size of block to be encrypted \ | |
178 | * \ | |
179 | * Returns: --- \ | |
180 | * \ | |
181 | * Use: Encrypts a block with a block cipher in CFB mode. The \ | |
182 | * input block may be arbitrary in size. CFB mode is not \ | |
183 | * sensitive to block boundaries. \ | |
184 | */ \ | |
185 | \ | |
186 | void pre##_cfbencrypt(pre##_cfbctx *ctx, \ | |
187 | const void *src, void *dest, \ | |
188 | size_t sz) \ | |
189 | { \ | |
190 | const octet *s = src; \ | |
191 | octet *d = dest; \ | |
426aab6b | 192 | unsigned off = ctx->off; \ |
79ba130c | 193 | \ |
194 | /* --- Empty blocks are trivial --- */ \ | |
195 | \ | |
196 | if (!sz) \ | |
197 | return; \ | |
198 | \ | |
199 | /* --- If I can deal with the block from my buffer, do that --- */ \ | |
200 | \ | |
201 | if (sz < PRE##_BLKSZ - off) \ | |
202 | goto small; \ | |
203 | \ | |
204 | /* --- Finish off what's left in my buffer --- */ \ | |
205 | \ | |
206 | while (off < PRE##_BLKSZ) { \ | |
207 | register octet x = *s++; \ | |
5c3f75ec | 208 | ctx->iv[off] ^= x; \ |
209 | if (d) *d++ = ctx->iv[off]; \ | |
210 | off++; \ | |
79ba130c | 211 | sz--; \ |
212 | } \ | |
213 | \ | |
214 | /* --- Main encryption loop --- */ \ | |
215 | \ | |
216 | { \ | |
217 | uint32 iv[PRE##_BLKSZ / 4]; \ | |
218 | BLKC_LOAD(PRE, iv, ctx->iv); \ | |
219 | \ | |
220 | for (;;) { \ | |
221 | pre##_eblk(&ctx->ctx, iv, iv); \ | |
222 | if (sz < PRE##_BLKSZ) \ | |
223 | break; \ | |
5c3f75ec | 224 | if (s) { \ |
225 | BLKC_XLOAD(PRE, iv, s); \ | |
45c0fd36 | 226 | s += PRE##_BLKSZ; \ |
5c3f75ec | 227 | } \ |
228 | if (d) { \ | |
45c0fd36 MW |
229 | BLKC_STORE(PRE, d, iv); \ |
230 | d += PRE##_BLKSZ; \ | |
5c3f75ec | 231 | } \ |
79ba130c | 232 | sz -= PRE##_BLKSZ; \ |
233 | } \ | |
234 | off = 0; \ | |
235 | BLKC_STORE(PRE, ctx->iv, iv); \ | |
236 | } \ | |
237 | \ | |
238 | /* --- Tidying up the tail end --- */ \ | |
239 | \ | |
240 | if (sz) { \ | |
241 | small: \ | |
242 | do { \ | |
243 | register octet x = *s++; \ | |
5c3f75ec | 244 | ctx->iv[off] ^= x; \ |
245 | if (d) *d++ = ctx->iv[off]; \ | |
246 | off++; \ | |
79ba130c | 247 | sz--; \ |
248 | } while (sz); \ | |
249 | } \ | |
250 | \ | |
251 | /* --- Done --- */ \ | |
252 | \ | |
253 | ctx->off = off; \ | |
254 | return; \ | |
255 | } \ | |
256 | \ | |
426aab6b | 257 | /* --- @pre_cfbdecrypt@ --- * \ |
79ba130c | 258 | * \ |
259 | * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \ | |
260 | * @const void *src@ = pointer to source data \ | |
261 | * @void *dest@ = pointer to destination data \ | |
262 | * @size_t sz@ = size of block to be encrypted \ | |
263 | * \ | |
264 | * Returns: --- \ | |
265 | * \ | |
266 | * Use: Decrypts a block with a block cipher in CFB mode. The \ | |
267 | * input block may be arbitrary in size. CFB mode is not \ | |
268 | * sensitive to block boundaries. \ | |
269 | */ \ | |
270 | \ | |
271 | void pre##_cfbdecrypt(pre##_cfbctx *ctx, \ | |
272 | const void *src, void *dest, \ | |
273 | size_t sz) \ | |
274 | { \ | |
275 | const octet *s = src; \ | |
276 | octet *d = dest; \ | |
426aab6b | 277 | unsigned off = ctx->off; \ |
79ba130c | 278 | \ |
279 | /* --- Empty blocks are trivial --- */ \ | |
280 | \ | |
281 | if (!sz) \ | |
282 | return; \ | |
283 | \ | |
284 | /* --- If I can deal with the block from my buffer, do that --- */ \ | |
285 | \ | |
286 | if (sz < PRE##_BLKSZ - off) \ | |
287 | goto small; \ | |
288 | \ | |
289 | /* --- Finish off what's left in my buffer --- */ \ | |
290 | \ | |
291 | while (off < PRE##_BLKSZ) { \ | |
292 | register octet x = *s++; \ | |
293 | *d++ = ctx->iv[off] ^ x; \ | |
294 | ctx->iv[off++] = x; \ | |
295 | sz--; \ | |
296 | } \ | |
297 | \ | |
298 | /* --- Main encryption loop --- */ \ | |
299 | \ | |
300 | { \ | |
301 | uint32 iv[PRE##_BLKSZ / 4]; \ | |
302 | BLKC_LOAD(PRE, iv, ctx->iv); \ | |
303 | \ | |
304 | for (;;) { \ | |
305 | uint32 x[PRE##_BLKSZ / 4]; \ | |
306 | pre##_eblk(&ctx->ctx, iv, iv); \ | |
307 | if (sz < PRE##_BLKSZ) \ | |
308 | break; \ | |
309 | BLKC_LOAD(PRE, x, s); \ | |
310 | BLKC_XSTORE(PRE, d, iv, x); \ | |
311 | BLKC_MOVE(PRE, iv, x); \ | |
312 | s += PRE##_BLKSZ; \ | |
313 | d += PRE##_BLKSZ; \ | |
314 | sz -= PRE##_BLKSZ; \ | |
315 | } \ | |
316 | off = 0; \ | |
317 | BLKC_STORE(PRE, ctx->iv, iv); \ | |
318 | } \ | |
319 | \ | |
320 | /* --- Tidying up the tail end --- */ \ | |
321 | \ | |
322 | if (sz) { \ | |
323 | small: \ | |
324 | do { \ | |
325 | register octet x = *s++; \ | |
326 | *d++ = ctx->iv[off] ^ x; \ | |
327 | ctx->iv[off++] = x; \ | |
328 | sz--; \ | |
329 | } while (sz); \ | |
330 | } \ | |
331 | \ | |
332 | /* --- Done --- */ \ | |
333 | \ | |
334 | ctx->off = off; \ | |
335 | return; \ | |
336 | } \ | |
337 | \ | |
338 | /* --- Generic cipher interface --- */ \ | |
339 | \ | |
340 | static const gcipher_ops gops; \ | |
341 | \ | |
342 | typedef struct gctx { \ | |
343 | gcipher c; \ | |
344 | pre##_cfbctx k; \ | |
345 | } gctx; \ | |
346 | \ | |
347 | static gcipher *ginit(const void *k, size_t sz) \ | |
348 | { \ | |
426aab6b | 349 | gctx *g = S_CREATE(gctx); \ |
79ba130c | 350 | g->c.ops = &gops; \ |
351 | pre##_cfbinit(&g->k, k, sz, 0); \ | |
352 | return (&g->c); \ | |
353 | } \ | |
354 | \ | |
355 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ | |
356 | { \ | |
357 | gctx *g = (gctx *)c; \ | |
358 | pre##_cfbencrypt(&g->k, s, t, sz); \ | |
359 | } \ | |
360 | \ | |
361 | static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \ | |
362 | { \ | |
363 | gctx *g = (gctx *)c; \ | |
364 | pre##_cfbdecrypt(&g->k, s, t, sz); \ | |
365 | } \ | |
366 | \ | |
367 | static void gdestroy(gcipher *c) \ | |
368 | { \ | |
369 | gctx *g = (gctx *)c; \ | |
426aab6b | 370 | BURN(*g); \ |
371 | S_DESTROY(g); \ | |
79ba130c | 372 | } \ |
373 | \ | |
374 | static void gsetiv(gcipher *c, const void *iv) \ | |
375 | { \ | |
376 | gctx *g = (gctx *)c; \ | |
377 | pre##_cfbsetiv(&g->k, iv); \ | |
378 | } \ | |
379 | \ | |
380 | static void gbdry(gcipher *c) \ | |
381 | { \ | |
382 | gctx *g = (gctx *)c; \ | |
383 | pre##_cfbbdry(&g->k); \ | |
384 | } \ | |
385 | \ | |
386 | static const gcipher_ops gops = { \ | |
426aab6b | 387 | &pre##_cfb, \ |
388 | gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \ | |
79ba130c | 389 | }; \ |
390 | \ | |
391 | const gccipher pre##_cfb = { \ | |
426aab6b | 392 | #pre "-cfb", pre##_keysz, PRE##_BLKSZ, \ |
79ba130c | 393 | ginit \ |
394 | }; \ | |
395 | \ | |
396 | CFB_TEST(PRE, pre) | |
397 | ||
398 | /*----- Test rig ----------------------------------------------------------*/ | |
399 | ||
400 | #ifdef TEST_RIG | |
401 | ||
402 | #include <stdio.h> | |
403 | ||
404 | #include "daftstory.h" | |
405 | ||
406 | /* --- @CFB_TEST@ --- * | |
407 | * | |
408 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions | |
409 | * | |
410 | * Use: Standard test rig for CFB functions. | |
411 | */ | |
412 | ||
413 | #define CFB_TEST(PRE, pre) \ | |
414 | \ | |
415 | /* --- Initial plaintext for the test --- */ \ | |
416 | \ | |
417 | static const octet text[] = TEXT; \ | |
418 | \ | |
419 | /* --- Key and IV to use --- */ \ | |
420 | \ | |
421 | static const octet key[] = KEY; \ | |
422 | static const octet iv[] = IV; \ | |
423 | \ | |
424 | /* --- Buffers for encryption and decryption output --- */ \ | |
425 | \ | |
426 | static octet ct[sizeof(text)]; \ | |
427 | static octet pt[sizeof(text)]; \ | |
428 | \ | |
12331b2d | 429 | static void hexdump(const octet *p, size_t sz, size_t off) \ |
79ba130c | 430 | { \ |
431 | const octet *q = p + sz; \ | |
432 | for (sz = 0; p < q; p++, sz++) { \ | |
433 | printf("%02x", *p); \ | |
12331b2d | 434 | if ((off + sz + 1) % PRE##_BLKSZ == 0) \ |
79ba130c | 435 | putchar(':'); \ |
436 | } \ | |
437 | } \ | |
438 | \ | |
439 | int main(void) \ | |
440 | { \ | |
441 | size_t sz = 0, rest; \ | |
442 | pre##_cfbctx ctx; \ | |
443 | int status = 0; \ | |
444 | int done = 0; \ | |
445 | pre##_ctx k; \ | |
446 | \ | |
447 | size_t keysz = PRE##_KEYSZ ? \ | |
448 | PRE##_KEYSZ : strlen((const char *)key); \ | |
449 | \ | |
450 | fputs(#pre "-cfb: ", stdout); \ | |
451 | \ | |
452 | pre##_init(&k, key, keysz); \ | |
453 | pre##_cfbsetkey(&ctx, &k); \ | |
454 | \ | |
455 | while (sz <= sizeof(text)) { \ | |
456 | rest = sizeof(text) - sz; \ | |
457 | memcpy(ct, text, sizeof(text)); \ | |
458 | pre##_cfbsetiv(&ctx, iv); \ | |
459 | pre##_cfbencrypt(&ctx, ct, ct, sz); \ | |
460 | pre##_cfbencrypt(&ctx, ct + sz, ct + sz, rest); \ | |
461 | memcpy(pt, ct, sizeof(text)); \ | |
462 | pre##_cfbsetiv(&ctx, iv); \ | |
463 | pre##_cfbdecrypt(&ctx, pt, pt, rest); \ | |
464 | pre##_cfbdecrypt(&ctx, pt + rest, pt + rest, sz); \ | |
465 | if (memcmp(pt, text, sizeof(text)) == 0) { \ | |
466 | done++; \ | |
467 | if (sizeof(text) < 40 || done % 8 == 0) \ | |
45c0fd36 | 468 | fputc('.', stdout); \ |
79ba130c | 469 | if (done % 480 == 0) \ |
45c0fd36 | 470 | fputs("\n\t", stdout); \ |
79ba130c | 471 | fflush(stdout); \ |
472 | } else { \ | |
473 | printf("\nError (sz = %lu)\n", (unsigned long)sz); \ | |
474 | status = 1; \ | |
12331b2d MW |
475 | printf("\tplaintext = "); hexdump(text, sz, 0); \ |
476 | printf(", "); hexdump(text + sz, rest, sz); \ | |
45c0fd36 | 477 | fputc('\n', stdout); \ |
12331b2d MW |
478 | printf("\tciphertext = "); hexdump(ct, sz, 0); \ |
479 | printf(", "); hexdump(ct + sz, rest, sz); \ | |
45c0fd36 | 480 | fputc('\n', stdout); \ |
12331b2d MW |
481 | printf("\trecovered text = "); hexdump(pt, sz, 0); \ |
482 | printf(", "); hexdump(pt + sz, rest, sz); \ | |
45c0fd36 | 483 | fputc('\n', stdout); \ |
79ba130c | 484 | fputc('\n', stdout); \ |
485 | } \ | |
486 | if (sz < 63) \ | |
487 | sz++; \ | |
488 | else \ | |
489 | sz += 9; \ | |
490 | } \ | |
491 | \ | |
492 | fputs(status ? " failed\n" : " ok\n", stdout); \ | |
493 | return (status); \ | |
494 | } | |
495 | ||
496 | #else | |
497 | # define CFB_TEST(PRE, pre) | |
498 | #endif | |
499 | ||
500 | /*----- That's all, folks -------------------------------------------------*/ | |
501 | ||
502 | #ifdef __cplusplus | |
503 | } | |
504 | #endif | |
505 | ||
506 | #endif |