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Merge branch '2.5.x'
[catacomb] / symm / cfb-def.h
1 /* -*-c-*-
2 *
3 * Definitions for ciphertext feedback mode
4 *
5 * (c) 1999 Straylight/Edgeware
6 */
7
8 /*----- Licensing notice --------------------------------------------------*
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.
16 *
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.
21 *
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
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
42 #ifndef CATACOMB_ARENA_H
43 # include "arena.h"
44 #endif
45
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
58 #ifndef CATACOMB_PARANOIA_H
59 # include "paranoia.h"
60 #endif
61
62 #ifndef CATACOMB_RSVR_H
63 # include "rsvr.h"
64 #endif
65
66 /*----- Macros ------------------------------------------------------------*/
67
68 /* --- @CFB_DEF@ --- *
69 *
70 * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
71 *
72 * Use: Creates an implementation for CFB mode.
73 */
74
75 #define CFB_DEF(PRE, pre) CFB_DEFX(PRE, pre, #pre, #pre)
76
77 #define CFB_DEFX(PRE, pre, name, fname) \
78 \
79 /* --- @pre_cfbgetiv@ --- * \
80 * \
81 * Arguments: @const pre_cfbctx *ctx@ = pointer to CFB context block \
82 * @void *iv@ = pointer to output data block \
83 * \
84 * Returns: --- \
85 * \
86 * Use: Reads the currently set IV. Reading and setting an IV \
87 * is not transparent to the cipher. It will add a `step' \
88 * which must be matched by a similar operation during \
89 * decryption. \
90 */ \
91 \
92 void pre##_cfbgetiv(const pre##_cfbctx *ctx, void *iv) \
93 { \
94 octet *p = iv; \
95 unsigned off = ctx->off; \
96 unsigned rest = PRE##_BLKSZ - off; \
97 \
98 memcpy(p, ctx->b + off, rest); \
99 memcpy(p + rest, ctx->b, off); \
100 } \
101 \
102 /* --- @pre_cfbsetiv@ --- * \
103 * \
104 * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
105 * @cnost void *iv@ = pointer to IV to set \
106 * \
107 * Returns: --- \
108 * \
109 * Use: Sets the IV to use for subsequent encryption. \
110 */ \
111 \
112 void pre##_cfbsetiv(pre##_cfbctx *ctx, const void *iv) \
113 { memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = 0; } \
114 \
115 /* --- @pre_cfbbdry@ --- * \
116 * \
117 * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
118 * \
119 * Returns: --- \
120 * \
121 * Use: Inserts a boundary during encryption. Successful \
122 * decryption must place a similar boundary. \
123 */ \
124 \
125 void pre##_cfbbdry(pre##_cfbctx *ctx) \
126 { \
127 uint32 t[PRE##_BLKSZ/4]; \
128 \
129 BLKC_LOAD(PRE, t, ctx->b); \
130 pre##_eblk(&ctx->ctx, t, t); \
131 BLKC_STORE(PRE, ctx->b, t); \
132 ctx->off = 0; \
133 BURN(t); \
134 } \
135 \
136 /* --- @pre_cfbsetkey@ --- * \
137 * \
138 * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
139 * @const pre_ctx *k@ = pointer to cipher context \
140 * \
141 * Returns: --- \
142 * \
143 * Use: Sets the CFB context to use a different cipher key. \
144 */ \
145 \
146 void pre##_cfbsetkey(pre##_cfbctx *ctx, const pre##_ctx *k) \
147 { ctx->ctx = *k; ctx->off = 0; } \
148 \
149 /* --- @pre_cfbinit@ --- * \
150 * \
151 * Arguments: @pre_cfbctx *ctx@ = pointer to cipher context \
152 * @const void *key@ = pointer to the key buffer \
153 * @size_t sz@ = size of the key \
154 * @const void *iv@ = pointer to initialization vector \
155 * \
156 * Returns: --- \
157 * \
158 * Use: Initializes a CFB context ready for use. You should \
159 * ensure that the IV chosen is unique: reusing an IV will \
160 * compromise the security of at least the first block \
161 * encrypted. This is equivalent to calls to @pre_init@, \
162 * @pre_cfbsetkey@ and @pre_cfbsetiv@. \
163 */ \
164 \
165 void pre##_cfbinit(pre##_cfbctx *ctx, \
166 const void *key, size_t sz, \
167 const void *iv) \
168 { \
169 static const octet zero[PRE##_BLKSZ] = { 0 }; \
170 \
171 pre##_init(&ctx->ctx, key, sz); \
172 pre##_cfbsetiv(ctx, iv ? iv : zero); \
173 } \
174 \
175 /* --- @pre_cfbencrypt@ --- * \
176 * \
177 * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
178 * @const void *src@ = pointer to source data \
179 * @void *dest@ = pointer to destination data \
180 * @size_t sz@ = size of block to be encrypted \
181 * \
182 * Returns: --- \
183 * \
184 * Use: Encrypts a block with a block cipher in CFB mode. The \
185 * input block may be arbitrary in size. CFB mode is not \
186 * sensitive to block boundaries. \
187 */ \
188 \
189 static const rsvr_policy pre##_cfbpolicy = { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
190 \
191 void pre##_cfbencrypt(pre##_cfbctx *ctx, \
192 const void *src, void *dest, \
193 size_t sz) \
194 { \
195 rsvr_plan plan; \
196 const octet *s = src; \
197 octet *d = dest, *p; \
198 uint32 t[PRE##_BLKSZ/4]; \
199 octet y; \
200 \
201 /* Construct a plan and prepare to follow through. */ \
202 rsvr_mkplan(&plan, &pre##_cfbpolicy, ctx->off, sz); \
203 BLKC_LOAD(PRE, t, ctx->b); \
204 \
205 /* Initial portion, fulfilled from the buffer. If the chunk is small \
206 * enough, then this will be the only portion. If the buffer is \
207 * currently empty, then we must prepare it. \
208 */ \
209 if (plan.head) { \
210 if (!ctx->off) { \
211 pre##_eblk(&ctx->ctx, t, t); \
212 BLKC_STORE(PRE, ctx->b, t); \
213 } \
214 p = ctx->b + ctx->off; ctx->off += plan.head; \
215 if (s) while (plan.head--) { y = *s++ ^ *p; *p++ = y; if (d) *d++ = y; } \
216 else if (d) { memcpy(d, p, plan.head); d += plan.head; } \
217 BLKC_LOAD(PRE, t, ctx->b); \
218 } \
219 \
220 /* If the buffer is all used, then reset it ready for next time. */ \
221 ctx->off -= plan.from_rsvr; \
222 \
223 /* Handle multiple whole blocks. */ \
224 if (!d) { \
225 if (!s) while (plan.from_input) { \
226 pre##_eblk(&ctx->ctx, t, t); \
227 plan.from_input -= PRE##_BLKSZ; \
228 } else while (plan.from_input) { \
229 pre##_eblk(&ctx->ctx, t, t); \
230 BLKC_XLOAD(PRE, t, s); s += PRE##_BLKSZ; \
231 plan.from_input -= PRE##_BLKSZ; \
232 } \
233 } else { \
234 if (!s) while (plan.from_input) { \
235 pre##_eblk(&ctx->ctx, t, t); \
236 BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \
237 plan.from_input -= PRE##_BLKSZ; \
238 } else while (plan.from_input) { \
239 pre##_eblk(&ctx->ctx, t, t); \
240 BLKC_XLOAD(PRE, t, s); s += PRE##_BLKSZ; \
241 BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \
242 plan.from_input -= PRE##_BLKSZ; \
243 } \
244 } \
245 \
246 /* Final portion. Note that the buffer must be empty if there is a \
247 * tail, since otherwise the input data would have been part of the \
248 * head portion instad. */ \
249 if (!plan.tail) \
250 BLKC_STORE(PRE, ctx->b, t); \
251 else { \
252 pre##_eblk(&ctx->ctx, t, t); \
253 BLKC_STORE(PRE, ctx->b, t); \
254 p = ctx->b; ctx->off += plan.tail; \
255 if (s) while (plan.tail--) { y = *s++ ^ *p; *p++ = y; if (d) *d++ = y; } \
256 else if (d) { memcpy(d, p, plan.tail); d += plan.tail; } \
257 } \
258 } \
259 \
260 /* --- @pre_cfbdecrypt@ --- * \
261 * \
262 * Arguments: @pre_cfbctx *ctx@ = pointer to CFB context block \
263 * @const void *src@ = pointer to source data \
264 * @void *dest@ = pointer to destination data \
265 * @size_t sz@ = size of block to be encrypted \
266 * \
267 * Returns: --- \
268 * \
269 * Use: Decrypts a block with a block cipher in CFB mode. The \
270 * input block may be arbitrary in size. CFB mode is not \
271 * sensitive to block boundaries. \
272 */ \
273 \
274 void pre##_cfbdecrypt(pre##_cfbctx *ctx, \
275 const void *src, void *dest, \
276 size_t sz) \
277 { \
278 rsvr_plan plan; \
279 const octet *s = src; \
280 octet *d = dest, *p; \
281 uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4]; \
282 octet y; \
283 \
284 /* Construct a plan and prepare to follow through. */ \
285 rsvr_mkplan(&plan, &pre##_cfbpolicy, ctx->off, sz); \
286 BLKC_LOAD(PRE, t, ctx->b); \
287 \
288 /* Initial portion, fulfilled from the buffer. If the chunk is small \
289 * enough, then this will be the only portion. If the buffer is \
290 * currently empty, then we must prepare it. \
291 */ \
292 if (plan.head) { \
293 if (!ctx->off) { \
294 pre##_eblk(&ctx->ctx, t, t); \
295 BLKC_STORE(PRE, ctx->b, t); \
296 } \
297 p = ctx->b + ctx->off; \
298 ctx->off += plan.head; \
299 while (plan.head--) { y = *s++; *d++ = y ^ *p; *p++ = y; } \
300 BLKC_LOAD(PRE, t, ctx->b); \
301 } \
302 \
303 /* If the buffer is all used, then reset it ready for next time. */ \
304 ctx->off -= plan.from_rsvr; \
305 \
306 /* Handle multiple whole blocks. */ \
307 while (plan.from_input) { \
308 pre##_eblk(&ctx->ctx, t, t); \
309 BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ; \
310 BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ; \
311 BLKC_MOVE(PRE, t, u); \
312 plan.from_input -= PRE##_BLKSZ; \
313 } \
314 \
315 /* Final portion. Note that the buffer must be empty if there is a \
316 * tail, since otherwise the input data would have been part of the \
317 * head portion instad. */ \
318 if (!plan.tail) \
319 BLKC_STORE(PRE, ctx->b, t); \
320 else { \
321 pre##_eblk(&ctx->ctx, t, t); \
322 BLKC_STORE(PRE, ctx->b, t); \
323 p = ctx->b; \
324 ctx->off += plan.tail; \
325 while (plan.tail--) { y = *s++; *d++ = y ^ *p; *p++ = y; } \
326 } \
327 } \
328 \
329 /* --- Generic cipher interface --- */ \
330 \
331 static const gcipher_ops gops; \
332 \
333 typedef struct gctx { \
334 gcipher c; \
335 pre##_cfbctx k; \
336 } gctx; \
337 \
338 static gcipher *ginit(const void *k, size_t sz) \
339 { \
340 gctx *g = S_CREATE(gctx); \
341 g->c.ops = &gops; \
342 pre##_cfbinit(&g->k, k, sz, 0); \
343 return (&g->c); \
344 } \
345 \
346 static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \
347 { gctx *g = (gctx *)c; pre##_cfbencrypt(&g->k, s, t, sz); } \
348 \
349 static void gdecrypt(gcipher *c, const void *s, void *t, size_t sz) \
350 { gctx *g = (gctx *)c; pre##_cfbdecrypt(&g->k, s, t, sz); } \
351 \
352 static void gdestroy(gcipher *c) \
353 { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); } \
354 \
355 static void gsetiv(gcipher *c, const void *iv) \
356 { gctx *g = (gctx *)c; pre##_cfbsetiv(&g->k, iv); } \
357 \
358 static void gbdry(gcipher *c) \
359 { gctx *g = (gctx *)c; pre##_cfbbdry(&g->k); } \
360 \
361 static const gcipher_ops gops = { \
362 &pre##_cfb, \
363 gencrypt, gdecrypt, gdestroy, gsetiv, gbdry \
364 }; \
365 \
366 const gccipher pre##_cfb = { \
367 name "-cfb", pre##_keysz, PRE##_BLKSZ, \
368 ginit \
369 }; \
370 \
371 CFB_TESTX(PRE, pre, name, fname)
372
373 /*----- Test rig ----------------------------------------------------------*/
374
375 #define CFB_TEST(PRE, pre) CFB_TESTX(PRE, pre, #pre, #pre)
376
377 #ifdef TEST_RIG
378
379 #include "modes-test.h"
380
381 /* --- @CFB_TEST@ --- *
382 *
383 * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
384 *
385 * Use: Standard test rig for CFB functions.
386 */
387
388 #define CFB_TESTX(PRE, pre, name, fname) \
389 \
390 static pre##_ctx key; \
391 static pre##_cfbctx ctx; \
392 \
393 static void pre##_cfb_test_setup(const octet *k, size_t ksz) \
394 { pre##_init(&key, k, ksz); pre##_cfbsetkey(&ctx, &key); } \
395 \
396 static void pre##_cfb_test_reset(const octet *iv) \
397 { pre##_cfbsetiv(&ctx, iv); } \
398 \
399 static void pre##_cfb_test_enc(const octet *s, octet *d, size_t sz) \
400 { pre##_cfbencrypt(&ctx, s, d, sz); } \
401 \
402 static void pre##_cfb_test_dec(const octet *s, octet *d, size_t sz) \
403 { pre##_cfbdecrypt(&ctx, s, d, sz); } \
404 \
405 int main(int argc, char *argv[]) \
406 { \
407 return test_encmode(fname "-cfb", PRE##_KEYSZ, PRE##_BLKSZ, 1, 0, \
408 pre##_cfb_test_setup, pre##_cfb_test_reset, \
409 pre##_cfb_test_enc, pre##_cfb_test_dec, \
410 argc, argv); \
411 }
412
413 #else
414 # define CFB_TESTX(PRE, pre, name, fname)
415 #endif
416
417 /*----- That's all, folks -------------------------------------------------*/
418
419 #ifdef __cplusplus
420 }
421 #endif
422
423 #endif
Catacomb cryptographic library