| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Block cipher counter mode (or long cycle mode) |
| 4 | * |
| 5 | * (c) 2000 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_COUNTER_DEF_H |
| 29 | #define CATACOMB_COUNTER_DEF_H |
| 30 | |
| 31 | #ifdef __cplusplus |
| 32 | extern "C" { |
| 33 | #endif |
| 34 | |
| 35 | /*----- Header files ------------------------------------------------------*/ |
| 36 | |
| 37 | #include <stdarg.h> |
| 38 | #include <string.h> |
| 39 | |
| 40 | #include <mLib/bits.h> |
| 41 | #include <mLib/sub.h> |
| 42 | |
| 43 | #ifndef CATACOMB_ARENA_H |
| 44 | # include "arena.h" |
| 45 | #endif |
| 46 | |
| 47 | #ifndef CATACOMB_BLKC_H |
| 48 | # include "blkc.h" |
| 49 | #endif |
| 50 | |
| 51 | #ifndef CATACOMB_GCIPHER_H |
| 52 | # include "gcipher.h" |
| 53 | #endif |
| 54 | |
| 55 | #ifndef CATACOMB_PARANOIA_H |
| 56 | # include "paranoia.h" |
| 57 | #endif |
| 58 | |
| 59 | #ifndef CATACOMB_RSVR_H |
| 60 | # include "rsvr.h" |
| 61 | #endif |
| 62 | |
| 63 | /*----- Macros ------------------------------------------------------------*/ |
| 64 | |
| 65 | /* --- @COUNTER_DEF@ --- * |
| 66 | * |
| 67 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
| 68 | * |
| 69 | * Use: Creates definitions for counter mode. |
| 70 | */ |
| 71 | |
| 72 | #define COUNTER_DEF(PRE, pre) COUNTER_DEFX(PRE, pre, #pre, #pre) |
| 73 | |
| 74 | #define COUNTER_DEFX(PRE, pre, name, fname) \ |
| 75 | \ |
| 76 | /* --- @pre_countergetiv@ --- * \ |
| 77 | * \ |
| 78 | * Arguments: @const pre_counterctx *ctx@ = pointer to counter \ |
| 79 | * context \ |
| 80 | * @void *iv@ = pointer to output data block \ |
| 81 | * \ |
| 82 | * Returns: --- \ |
| 83 | * \ |
| 84 | * Use: Reads the currently set IV. Reading and setting an IV \ |
| 85 | * is not transparent to the cipher. It will add a `step' \ |
| 86 | * which must be matched by a similar operation during \ |
| 87 | * decryption. \ |
| 88 | */ \ |
| 89 | \ |
| 90 | void pre##_countergetiv(const pre##_counterctx *ctx, void *iv) \ |
| 91 | { BLKC_STORE(PRE, iv, ctx->c); } \ |
| 92 | \ |
| 93 | /* --- @pre_countersetiv@ --- * \ |
| 94 | * \ |
| 95 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
| 96 | * @cnost void *iv@ = pointer to IV to set \ |
| 97 | * \ |
| 98 | * Returns: --- \ |
| 99 | * \ |
| 100 | * Use: Sets the IV to use for subsequent encryption. \ |
| 101 | */ \ |
| 102 | \ |
| 103 | void pre##_countersetiv(pre##_counterctx *ctx, const void *iv) \ |
| 104 | { BLKC_LOAD(PRE, ctx->c, iv); ctx->off = PRE##_BLKSZ; } \ |
| 105 | \ |
| 106 | /* --- @pre_counterbdry@ --- * \ |
| 107 | * \ |
| 108 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
| 109 | * \ |
| 110 | * Returns: --- \ |
| 111 | * \ |
| 112 | * Use: Inserts a boundary during encryption. Successful \ |
| 113 | * decryption must place a similar boundary. \ |
| 114 | */ \ |
| 115 | \ |
| 116 | void pre##_counterbdry(pre##_counterctx *ctx) \ |
| 117 | { BLKC_STEP(PRE, ctx->c); ctx->off = PRE##_BLKSZ; } \ |
| 118 | \ |
| 119 | /* --- @pre_countersetkey@ --- * \ |
| 120 | * \ |
| 121 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
| 122 | * @const pre_ctx *k@ = pointer to cipher context \ |
| 123 | * \ |
| 124 | * Returns: --- \ |
| 125 | * \ |
| 126 | * Use: Sets the counter context to use a different cipher key. \ |
| 127 | */ \ |
| 128 | \ |
| 129 | void pre##_countersetkey(pre##_counterctx *ctx, const pre##_ctx *k) \ |
| 130 | { ctx->ctx = *k; } \ |
| 131 | \ |
| 132 | /* --- @pre_counterinit@ --- * \ |
| 133 | * \ |
| 134 | * Arguments: @pre_counterctx *ctx@ = pointer to cipher context \ |
| 135 | * @const void *key@ = pointer to the key buffer \ |
| 136 | * @size_t sz@ = size of the key \ |
| 137 | * @const void *iv@ = pointer to initialization vector \ |
| 138 | * \ |
| 139 | * Returns: --- \ |
| 140 | * \ |
| 141 | * Use: Initializes a counter context ready for use. You \ |
| 142 | * should ensure that the IV chosen is unique: reusing an \ |
| 143 | * IV will compromise the security of the entire \ |
| 144 | * plaintext. This is equivalent to calls to @pre_init@, \ |
| 145 | * @pre_countersetkey@ and @pre_countersetiv@. \ |
| 146 | */ \ |
| 147 | \ |
| 148 | void pre##_counterinit(pre##_counterctx *ctx, \ |
| 149 | const void *key, size_t sz, \ |
| 150 | const void *iv) \ |
| 151 | { \ |
| 152 | static const octet zero[PRE##_BLKSZ] = { 0 }; \ |
| 153 | \ |
| 154 | pre##_init(&ctx->ctx, key, sz); \ |
| 155 | pre##_countersetiv(ctx, iv ? iv : zero); \ |
| 156 | } \ |
| 157 | \ |
| 158 | /* --- @pre_counterencrypt@ --- * \ |
| 159 | * \ |
| 160 | * Arguments: @pre_counterctx *ctx@ = pointer to counter context \ |
| 161 | * @const void *src@ = pointer to source data \ |
| 162 | * @void *dest@ = pointer to destination data \ |
| 163 | * @size_t sz@ = size of block to be encrypted \ |
| 164 | * \ |
| 165 | * Returns: --- \ |
| 166 | * \ |
| 167 | * Use: Encrypts or decrypts a block with a block cipher in \ |
| 168 | * counter mode: encryption and decryption are the same in \ |
| 169 | * counter. The destination may be null to just churn the \ |
| 170 | * feedback round for a bit. The source may be null to \ |
| 171 | * use the cipher as a random data generator. \ |
| 172 | */ \ |
| 173 | \ |
| 174 | static const rsvr_policy pre##_counterpolicy = \ |
| 175 | { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \ |
| 176 | \ |
| 177 | void pre##_counterencrypt(pre##_counterctx *ctx, \ |
| 178 | const void *src, void *dest, \ |
| 179 | size_t sz) \ |
| 180 | { \ |
| 181 | rsvr_plan plan; \ |
| 182 | const octet *s = src, *p; \ |
| 183 | octet *d = dest; \ |
| 184 | uint32 t[PRE##_BLKSZ/4]; \ |
| 185 | \ |
| 186 | /* Construct a plan and prepare to follow through. */ \ |
| 187 | rsvr_mkplan(&plan, &pre##_counterpolicy, ctx->off, sz); \ |
| 188 | \ |
| 189 | /* Initial portion, fulfilled from the buffer. If the chunk is small \ |
| 190 | * enough, then this will be the only portion. If the buffer is \ |
| 191 | * currently empty, then we must prepare it. \ |
| 192 | */ \ |
| 193 | if (plan.head) { \ |
| 194 | if (!ctx->off) { \ |
| 195 | pre##_eblk(&ctx->ctx, ctx->c, t); BLKC_STEP(PRE, ctx->c); \ |
| 196 | BLKC_STORE(PRE, ctx->b, t); \ |
| 197 | } \ |
| 198 | p = ctx->b + ctx->off; ctx->off += plan.head; \ |
| 199 | if (!d) /* nothing to do */; \ |
| 200 | else if (!s) { memcpy(d, p, plan.head); d += plan.head; } \ |
| 201 | else while (plan.head--) *d++ = *s++ ^ *p++; \ |
| 202 | } \ |
| 203 | \ |
| 204 | /* If the buffer is all used, then reset it ready for next time. */ \ |
| 205 | ctx->off -= plan.from_rsvr; \ |
| 206 | \ |
| 207 | /* Handle multiple whole blocks. */ \ |
| 208 | if (!d) \ |
| 209 | BLKC_ADD(PRE, ctx->c, plan.from_input/PRE##_BLKSZ); \ |
| 210 | else if (!s) while (plan.from_input) { \ |
| 211 | pre##_eblk(&ctx->ctx, ctx->c, t); BLKC_STEP(PRE, ctx->c); \ |
| 212 | BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \ |
| 213 | plan.from_input -= PRE##_BLKSZ; \ |
| 214 | } else while (plan.from_input) { \ |
| 215 | pre##_eblk(&ctx->ctx, ctx->c, t); BLKC_STEP(PRE, ctx->c); \ |
| 216 | BLKC_XLOAD(PRE, t, s); s += PRE##_BLKSZ; \ |
| 217 | BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \ |
| 218 | plan.from_input -= PRE##_BLKSZ; \ |
| 219 | } \ |
| 220 | \ |
| 221 | /* Final portion. Note that the buffer must be empty if there is a \ |
| 222 | * tail, since otherwise the input data would have been part of the \ |
| 223 | * head portion instad. */ \ |
| 224 | if (!plan.tail) \ |
| 225 | BLKC_STORE(PRE, ctx->b, t); \ |
| 226 | else { \ |
| 227 | pre##_eblk(&ctx->ctx, ctx->c, t); BLKC_STEP(PRE, ctx->c); \ |
| 228 | BLKC_STORE(PRE, ctx->b, t); \ |
| 229 | p = ctx->b; ctx->off += plan.tail; \ |
| 230 | if (!d) /* nothing to do */; \ |
| 231 | else if (!s) { memcpy(d, p, plan.tail); d += plan.tail; } \ |
| 232 | else while (plan.tail--) *d++ = *s++ ^ *p++; \ |
| 233 | } \ |
| 234 | } \ |
| 235 | \ |
| 236 | /* --- Generic cipher interface --- */ \ |
| 237 | \ |
| 238 | static const gcipher_ops gops; \ |
| 239 | \ |
| 240 | typedef struct gctx { \ |
| 241 | gcipher c; \ |
| 242 | pre##_counterctx k; \ |
| 243 | } gctx; \ |
| 244 | \ |
| 245 | static gcipher *ginit(const void *k, size_t sz) \ |
| 246 | { \ |
| 247 | gctx *g = S_CREATE(gctx); \ |
| 248 | g->c.ops = &gops; \ |
| 249 | pre##_counterinit(&g->k, k, sz, 0); \ |
| 250 | return (&g->c); \ |
| 251 | } \ |
| 252 | \ |
| 253 | static void gencrypt(gcipher *c, const void *s, void *t, size_t sz) \ |
| 254 | { gctx *g = (gctx *)c; pre##_counterencrypt(&g->k, s, t, sz); } \ |
| 255 | \ |
| 256 | static void gdestroy(gcipher *c) \ |
| 257 | { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); } \ |
| 258 | \ |
| 259 | static void gsetiv(gcipher *c, const void *iv) \ |
| 260 | { gctx *g = (gctx *)c; pre##_countersetiv(&g->k, iv); } \ |
| 261 | \ |
| 262 | static void gbdry(gcipher *c) \ |
| 263 | { gctx *g = (gctx *)c; pre##_counterbdry(&g->k); } \ |
| 264 | \ |
| 265 | static const gcipher_ops gops = { \ |
| 266 | &pre##_counter, \ |
| 267 | gencrypt, gencrypt, gdestroy, gsetiv, gbdry \ |
| 268 | }; \ |
| 269 | \ |
| 270 | const gccipher pre##_counter = { \ |
| 271 | name "-counter", pre##_keysz, PRE##_BLKSZ, \ |
| 272 | ginit \ |
| 273 | }; \ |
| 274 | \ |
| 275 | /* --- Generic random number generator interface --- */ \ |
| 276 | \ |
| 277 | typedef struct grctx { \ |
| 278 | grand r; \ |
| 279 | pre##_counterctx k; \ |
| 280 | } grctx; \ |
| 281 | \ |
| 282 | static void grdestroy(grand *r) \ |
| 283 | { \ |
| 284 | grctx *g = (grctx *)r; \ |
| 285 | BURN(*g); \ |
| 286 | S_DESTROY(g); \ |
| 287 | } \ |
| 288 | \ |
| 289 | static int grmisc(grand *r, unsigned op, ...) \ |
| 290 | { \ |
| 291 | grctx *g = (grctx *)r; \ |
| 292 | va_list ap; \ |
| 293 | int rc = 0; \ |
| 294 | octet buf[PRE##_BLKSZ]; \ |
| 295 | va_start(ap, op); \ |
| 296 | \ |
| 297 | switch (op) { \ |
| 298 | case GRAND_CHECK: \ |
| 299 | switch (va_arg(ap, unsigned)) { \ |
| 300 | case GRAND_CHECK: \ |
| 301 | case GRAND_SEEDINT: \ |
| 302 | case GRAND_SEEDUINT32: \ |
| 303 | case GRAND_SEEDBLOCK: \ |
| 304 | case GRAND_SEEDRAND: \ |
| 305 | rc = 1; \ |
| 306 | break; \ |
| 307 | default: \ |
| 308 | rc = 0; \ |
| 309 | break; \ |
| 310 | } \ |
| 311 | break; \ |
| 312 | case GRAND_SEEDINT: \ |
| 313 | BLKC_SET(PRE, g->k.c, va_arg(ap, unsigned)); \ |
| 314 | g->k.off = PRE##_BLKSZ; \ |
| 315 | break; \ |
| 316 | case GRAND_SEEDUINT32: \ |
| 317 | BLKC_SET(PRE, g->k.c, va_arg(ap, uint32)); \ |
| 318 | g->k.off = PRE##_BLKSZ; \ |
| 319 | break; \ |
| 320 | case GRAND_SEEDBLOCK: { \ |
| 321 | const void *p = va_arg(ap, const void *); \ |
| 322 | size_t sz = va_arg(ap, size_t); \ |
| 323 | if (sz < sizeof(buf)) { \ |
| 324 | memset(buf, 0, sizeof(buf)); \ |
| 325 | memcpy(buf, p, sz); \ |
| 326 | p = buf; \ |
| 327 | } \ |
| 328 | pre##_countersetiv(&g->k, p); \ |
| 329 | } break; \ |
| 330 | case GRAND_SEEDRAND: { \ |
| 331 | grand *rr = va_arg(ap, grand *); \ |
| 332 | rr->ops->fill(rr, buf, sizeof(buf)); \ |
| 333 | pre##_countersetiv(&g->k, buf); \ |
| 334 | } break; \ |
| 335 | default: \ |
| 336 | GRAND_BADOP; \ |
| 337 | break; \ |
| 338 | } \ |
| 339 | \ |
| 340 | va_end(ap); \ |
| 341 | return (rc); \ |
| 342 | } \ |
| 343 | \ |
| 344 | static octet grbyte(grand *r) \ |
| 345 | { \ |
| 346 | grctx *g = (grctx *)r; \ |
| 347 | octet o; \ |
| 348 | pre##_counterencrypt(&g->k, 0, &o, 1); \ |
| 349 | return (o); \ |
| 350 | } \ |
| 351 | \ |
| 352 | static uint32 grword(grand *r) \ |
| 353 | { \ |
| 354 | grctx *g = (grctx *)r; \ |
| 355 | octet b[4]; \ |
| 356 | pre##_counterencrypt(&g->k, 0, b, sizeof(b)); \ |
| 357 | return (LOAD32(b)); \ |
| 358 | } \ |
| 359 | \ |
| 360 | static void grfill(grand *r, void *p, size_t sz) \ |
| 361 | { grctx *g = (grctx *)r; pre##_counterencrypt(&g->k, 0, p, sz); } \ |
| 362 | \ |
| 363 | static const grand_ops grops = { \ |
| 364 | name "-counter", \ |
| 365 | GRAND_CRYPTO, 0, \ |
| 366 | grmisc, grdestroy, \ |
| 367 | grword, grbyte, grword, grand_defaultrange, grfill \ |
| 368 | }; \ |
| 369 | \ |
| 370 | /* --- @pre_counterrand@ --- * \ |
| 371 | * \ |
| 372 | * Arguments: @const void *k@ = pointer to key material \ |
| 373 | * @size_t sz@ = size of key material \ |
| 374 | * \ |
| 375 | * Returns: Pointer to generic random number generator interface. \ |
| 376 | * \ |
| 377 | * Use: Creates a random number interface wrapper around an \ |
| 378 | * counter-mode block cipher. \ |
| 379 | */ \ |
| 380 | \ |
| 381 | grand *pre##_counterrand(const void *k, size_t sz) \ |
| 382 | { \ |
| 383 | grctx *g = S_CREATE(grctx); \ |
| 384 | g->r.ops = &grops; \ |
| 385 | pre##_counterinit(&g->k, k, sz, 0); \ |
| 386 | return (&g->r); \ |
| 387 | } \ |
| 388 | \ |
| 389 | COUNTER_TESTX(PRE, pre, name, fname) |
| 390 | |
| 391 | /*----- Test rig ----------------------------------------------------------*/ |
| 392 | |
| 393 | #define COUNTER_TEST(PRE, pre) COUNTER_TESTX(PRE, pre, #pre, #pre) |
| 394 | |
| 395 | #ifdef TEST_RIG |
| 396 | |
| 397 | #include "modes-test.h" |
| 398 | |
| 399 | /* --- @COUNTER_TEST@ --- * |
| 400 | * |
| 401 | * Arguments: @PRE@, @pre@ = prefixes for block cipher definitions |
| 402 | * |
| 403 | * Use: Standard test rig for counter functions. |
| 404 | */ |
| 405 | |
| 406 | #define COUNTER_TESTX(PRE, pre, name, fname) \ |
| 407 | \ |
| 408 | static pre##_ctx key; \ |
| 409 | static pre##_counterctx ctx; \ |
| 410 | \ |
| 411 | static void pre##_counter_test_setup(const octet *k, size_t ksz) \ |
| 412 | { pre##_init(&key, k, ksz); pre##_countersetkey(&ctx, &key); } \ |
| 413 | \ |
| 414 | static void pre##_counter_test_reset(const octet *iv) \ |
| 415 | { pre##_countersetiv(&ctx, iv); } \ |
| 416 | \ |
| 417 | static void pre##_counter_test_enc(const octet *s, octet *d, size_t sz) \ |
| 418 | { pre##_counterencrypt(&ctx, s, d, sz); } \ |
| 419 | \ |
| 420 | int main(int argc, char *argv[]) \ |
| 421 | { \ |
| 422 | return test_encmode(fname "-counter", PRE##_KEYSZ, PRE##_BLKSZ, 1, 0, \ |
| 423 | pre##_counter_test_setup, pre##_counter_test_reset, \ |
| 424 | pre##_counter_test_enc, pre##_counter_test_enc, \ |
| 425 | argc, argv); \ |
| 426 | } |
| 427 | |
| 428 | #else |
| 429 | # define COUNTER_TESTX(PRE, pre, name, fname) |
| 430 | #endif |
| 431 | |
| 432 | /*----- That's all, folks -------------------------------------------------*/ |
| 433 | |
| 434 | #ifdef __cplusplus |
| 435 | } |
| 436 | #endif |
| 437 | |
| 438 | #endif |