| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * The EAX authenticated-encryption mode |
| 4 | * |
| 5 | * (c) 2017 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_EAX_DEF_H |
| 29 | #define CATACOMB_EAX_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_CT_H |
| 51 | # include "ct.h" |
| 52 | #endif |
| 53 | |
| 54 | #ifndef CATACOMB_CMAC_H |
| 55 | # include "cmac.h" |
| 56 | #endif |
| 57 | |
| 58 | #ifndef CATACOMB_CMAC_DEF_H |
| 59 | # include "cmac-def.h" |
| 60 | #endif |
| 61 | |
| 62 | #ifndef CATACOMB_KEYSZ_H |
| 63 | # include "keysz.h" |
| 64 | #endif |
| 65 | |
| 66 | #ifndef CATACOMB_PARANOIA_H |
| 67 | # include "paranoia.h" |
| 68 | #endif |
| 69 | |
| 70 | #ifndef CATACOMB_RSVR_H |
| 71 | # include "rsvr.h" |
| 72 | #endif |
| 73 | |
| 74 | /*----- Macros ------------------------------------------------------------*/ |
| 75 | |
| 76 | /* --- @EAX_DEF@ --- * |
| 77 | * |
| 78 | * Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher |
| 79 | * |
| 80 | * Use: Creates an implementation for the EAX authenticated- |
| 81 | * encryption mode. |
| 82 | */ |
| 83 | |
| 84 | #define EAX_DEF(PRE, pre) EAX_DEFX(PRE, pre, #pre, #pre) |
| 85 | |
| 86 | #define EAX_DEFX(PRE, pre, name, fname) \ |
| 87 | \ |
| 88 | OMAC_DECL(PRE, pre) \ |
| 89 | \ |
| 90 | const octet \ |
| 91 | pre##_eaxnoncesz[] = { KSZ_ANY, PRE##_BLKSZ }, \ |
| 92 | pre##_eaxtagsz[] = { KSZ_RANGE, PRE##_BLKSZ, 0, PRE##_BLKSZ, 1 }; \ |
| 93 | \ |
| 94 | /* --- @pre_eaxsetkey@ --- * \ |
| 95 | * \ |
| 96 | * Arguments: @pre_eaxkey *key@ = pointer to key block to fill in \ |
| 97 | * @const void *k@ = pointer to key material \ |
| 98 | * @size_t ksz@ = size of key material \ |
| 99 | * \ |
| 100 | * Returns: --- \ |
| 101 | * \ |
| 102 | * Use: Initializes an EAX key block. \ |
| 103 | */ \ |
| 104 | \ |
| 105 | void pre##_eaxsetkey(pre##_eaxkey *key, const void *k, size_t ksz) \ |
| 106 | { \ |
| 107 | uint32 t[PRE##_BLKSZ/4]; \ |
| 108 | \ |
| 109 | /* Initialize the block cipher. */ \ |
| 110 | pre##_init(&key->ctx, k, ksz); \ |
| 111 | \ |
| 112 | /* Set up the OMAC masks. */ \ |
| 113 | pre##_omacmasks(&key->ctx, key->m0, key->m1); \ |
| 114 | \ |
| 115 | /* Set up the OMAC tweaks. EAX tweaks its MAC by simply stitching \ |
| 116 | * magic block-wide prefixes %$t_0$%, %$t_1$%, %$t_2$% (which are \ |
| 117 | * simply the numbers 0, 1, 2) on the front of strings. We can \ |
| 118 | * accelerate things by caching two values for each tweak: \ |
| 119 | * \ |
| 120 | * * %$v_i = E_K(t_i)$% is the accumulator that results from \ |
| 121 | * pushing the tweak through the blockcipher, which we'd \ |
| 122 | * calculate if the original message was nonempty. \ |
| 123 | * \ |
| 124 | * * %$z_i = E_K(t_0 \xor m_0)$% is the tweak with the `full final \ |
| 125 | * buffer' mask applied, which is the final tag for a final empty \ |
| 126 | * message. \ |
| 127 | */ \ |
| 128 | BLKC_BSET(PRE, t, 0); pre##_eblk(&key->ctx, t, key->v0); \ |
| 129 | BLKC_XMOVE(PRE, t, key->m0); pre##_eblk(&key->ctx, t, key->z0); \ |
| 130 | BLKC_BSET(PRE, t, 1); pre##_eblk(&key->ctx, t, key->v1); \ |
| 131 | BLKC_XMOVE(PRE, t, key->m0); pre##_eblk(&key->ctx, t, key->z1); \ |
| 132 | BLKC_BSET(PRE, t, 2); pre##_eblk(&key->ctx, t, key->v2); \ |
| 133 | BLKC_XMOVE(PRE, t, key->m0); pre##_eblk(&key->ctx, t, key->z2); \ |
| 134 | } \ |
| 135 | \ |
| 136 | /* --- @pre_eaxaadinit@ --- * \ |
| 137 | * \ |
| 138 | * Arguments: @pre_eaxaadctx *aad@ = pointer to AAD context \ |
| 139 | * @const pre_eaxkey *key@ = pointer to key block \ |
| 140 | * \ |
| 141 | * Returns: --- \ |
| 142 | * \ |
| 143 | * Use: Initializes an EAX AAD (`additional authenticated \ |
| 144 | * data') context associated with a given key. AAD \ |
| 145 | * contexts can be copied and/or reused, saving time if \ |
| 146 | * the AAD for a number of messages has a common prefix. \ |
| 147 | * \ |
| 148 | * The @key@ doesn't need to be kept around, though \ |
| 149 | * usually there'll at least be another copy in some EAX \ |
| 150 | * operation context because the AAD on its own isn't much \ |
| 151 | * good. \ |
| 152 | */ \ |
| 153 | \ |
| 154 | void pre##_eaxaadinit(pre##_eaxaadctx *aad, const pre##_eaxkey *key) \ |
| 155 | { aad->k = *key; aad->off = 0; BLKC_MOVE(PRE, aad->a, key->v1); } \ |
| 156 | \ |
| 157 | /* --- @pre_eaxaadhash@ --- * \ |
| 158 | * \ |
| 159 | * Arguments: @pre_eaxaadctx *aad@ = pointer to AAD context \ |
| 160 | * @const void *p@ = pointer to AAD material \ |
| 161 | * @size_t sz@ = length of AAD material \ |
| 162 | * \ |
| 163 | * Returns: --- \ |
| 164 | * \ |
| 165 | * Use: Feeds AAD into the context. \ |
| 166 | */ \ |
| 167 | \ |
| 168 | void pre##_eaxaadhash(pre##_eaxaadctx *aad, const void *p, size_t sz) \ |
| 169 | { \ |
| 170 | rsvr_state st; \ |
| 171 | const octet *q; \ |
| 172 | \ |
| 173 | rsvr_setup(&st, &pre##_omacpolicy, aad->b, &aad->off, p, sz); \ |
| 174 | RSVR_DO(&st) while ((q = RSVR_NEXT(&st, PRE##_BLKSZ)) != 0) \ |
| 175 | OMAC_BLOCK(PRE, pre, &aad->k.ctx, aad->a, q); \ |
| 176 | } \ |
| 177 | \ |
| 178 | /* --- @pre_eaxinit@ --- * \ |
| 179 | * \ |
| 180 | * Arguments: @pre_eaxctx *ctx@ = pointer to EAX context \ |
| 181 | * @const pre_eaxkey *key@ = pointer to key block \ |
| 182 | * @const void *n@ = pointer to nonce \ |
| 183 | * @size_t nsz@ = size of nonce \ |
| 184 | * \ |
| 185 | * Returns: --- \ |
| 186 | * \ |
| 187 | * Use: Initialize an EAX operation context with a given key. \ |
| 188 | * \ |
| 189 | * The original key needn't be kept around any more. \ |
| 190 | */ \ |
| 191 | \ |
| 192 | void pre##_eaxinit(pre##_eaxctx *ctx, const pre##_eaxkey *k, \ |
| 193 | const void *n, size_t nsz) \ |
| 194 | { ctx->k = *k; pre##_eaxreinit(ctx, n, nsz); } \ |
| 195 | \ |
| 196 | /* --- @pre_eaxreinit@ --- * \ |
| 197 | * \ |
| 198 | * Arguments: @pre_eaxctx *ctx@ = pointer to EAX context \ |
| 199 | * @const void *n@ = pointer to nonce \ |
| 200 | * @size_t nsz@ = size of nonce \ |
| 201 | * \ |
| 202 | * Returns: --- \ |
| 203 | * \ |
| 204 | * Use: Reinitialize an EAX operation context, changing the \ |
| 205 | * nonce. \ |
| 206 | */ \ |
| 207 | \ |
| 208 | void pre##_eaxreinit(pre##_eaxctx *ctx, const void *n, size_t nsz) \ |
| 209 | { \ |
| 210 | octet b[PRE##_BLKSZ]; \ |
| 211 | const octet *q = n; \ |
| 212 | \ |
| 213 | /* Initialize the OMAC context with the right tweak. */ \ |
| 214 | BLKC_MOVE(PRE, ctx->a, ctx->k.v2); \ |
| 215 | ctx->off = 0; \ |
| 216 | \ |
| 217 | /* Calculate the initial counter from the nonce. This is OMAC again, \ |
| 218 | * but this time we know that we're starting from a clean slate and \ |
| 219 | * we have the whole input in one go, so we don't bother with the \ |
| 220 | * full reservoir machinery. \ |
| 221 | */ \ |
| 222 | if (!nsz) \ |
| 223 | BLKC_MOVE(PRE, ctx->c0, ctx->k.z0); \ |
| 224 | else { \ |
| 225 | BLKC_MOVE(PRE, ctx->c0, ctx->k.v0); \ |
| 226 | while (nsz > PRE##_BLKSZ) { \ |
| 227 | OMAC_BLOCK(PRE, pre, &ctx->k.ctx, ctx->c0, q); \ |
| 228 | q += PRE##_BLKSZ; nsz -= PRE##_BLKSZ; \ |
| 229 | } \ |
| 230 | memcpy(b, q, nsz); \ |
| 231 | pre##_omacdone(&ctx->k.ctx, ctx->k.m0, ctx->k.m1, \ |
| 232 | ctx->c0, b, nsz); \ |
| 233 | } \ |
| 234 | \ |
| 235 | /* We must remember the initial counter for the final tag \ |
| 236 | * calculation. (I conjecture that storing the final counter instead \ |
| 237 | * would be just as secure, and require less state, but I've not \ |
| 238 | * proven this, and anyway it wouldn't interoperate.) Copy it to \ |
| 239 | * make the working counter. \ |
| 240 | */ \ |
| 241 | BLKC_MOVE(PRE, ctx->c, ctx->c0); \ |
| 242 | } \ |
| 243 | \ |
| 244 | /* --- @pre_eaxencrypt@ --- * \ |
| 245 | * \ |
| 246 | * Arguments: @pre_eaxctx *ctx@ = pointer to EAX operation context \ |
| 247 | * @const void *src@ = pointer to plaintext message chunk \ |
| 248 | * @size_t sz@ = size of the plaintext \ |
| 249 | * @buf *dst@ = a buffer to write the ciphertext to \ |
| 250 | * \ |
| 251 | * Returns: Zero on success; @-1@ on failure. \ |
| 252 | * \ |
| 253 | * Use: Encrypts a chunk of a plaintext message, writing a \ |
| 254 | * chunk of ciphertext to the output buffer and updating \ |
| 255 | * the operation state. \ |
| 256 | * \ |
| 257 | * For EAX, we always write a ciphertext chunk the same \ |
| 258 | * size as the plaintext. The messing about with @buf@ \ |
| 259 | * objects makes the interface consistent with other AEAD \ |
| 260 | * schemes which can't do this. \ |
| 261 | */ \ |
| 262 | \ |
| 263 | int pre##_eaxencrypt(pre##_eaxctx *ctx, \ |
| 264 | const void *src, size_t sz, buf *dst) \ |
| 265 | { \ |
| 266 | rsvr_plan plan; \ |
| 267 | uint32 t[PRE##_BLKSZ/4]; \ |
| 268 | const octet *p = src; \ |
| 269 | octet *q, *r, y; \ |
| 270 | \ |
| 271 | /* Allocate space for the ciphertext. */ \ |
| 272 | if (sz) { q = buf_get(dst, sz); if (!q) return (-1); } \ |
| 273 | else q = 0; \ |
| 274 | \ |
| 275 | /* Determine the buffering plan. Our buffer is going to do double- \ |
| 276 | * duty here. The end portion is going to contain mask from the \ |
| 277 | * encrypted counter which we mix into the plaintext to encrypt it; \ |
| 278 | * the start portion, which originally contained mask bytes we've \ |
| 279 | * already used, will hold the output ciphertext, which will \ |
| 280 | * eventually be collected into the OMAC state. \ |
| 281 | */ \ |
| 282 | rsvr_mkplan(&plan, &pre##_omacpolicy, ctx->off, sz); \ |
| 283 | \ |
| 284 | /* Initial portion, fulfilled from the buffer. If the buffer is \ |
| 285 | * empty, then that means that we haven't yet encrypted the current \ |
| 286 | * counter, so we should do that and advance it. \ |
| 287 | */ \ |
| 288 | if (plan.head) { \ |
| 289 | if (!ctx->off) { \ |
| 290 | pre##_eblk(&ctx->k.ctx, ctx->c, t); BLKC_BSTEP(PRE, ctx->c); \ |
| 291 | BLKC_STORE(PRE, ctx->b, t); \ |
| 292 | } \ |
| 293 | r = ctx->b + ctx->off; ctx->off += plan.head; \ |
| 294 | while (plan.head--) { y = *p++ ^ *r; *r++ = *q++ = y; } \ |
| 295 | } \ |
| 296 | \ |
| 297 | /* If we've filled up the buffer then we need to cycle the MAC and \ |
| 298 | * reset the offset. \ |
| 299 | */ \ |
| 300 | if (plan.from_rsvr) { \ |
| 301 | OMAC_BLOCK(PRE, pre, &ctx->k.ctx, ctx->a, ctx->b); \ |
| 302 | ctx->off = 0; \ |
| 303 | } \ |
| 304 | \ |
| 305 | /* Now to process the main body of the input. We sneakily open-code \ |
| 306 | * the OMAC part of this. \ |
| 307 | */ \ |
| 308 | while (plan.from_input) { \ |
| 309 | pre##_eblk(&ctx->k.ctx, ctx->c, t); BLKC_BSTEP(PRE, ctx->c); \ |
| 310 | BLKC_XLOAD(PRE, t, p); p += PRE##_BLKSZ; \ |
| 311 | BLKC_STORE(PRE, q, t); q += PRE##_BLKSZ; \ |
| 312 | BLKC_XMOVE(PRE, ctx->a, t); pre##_eblk(&ctx->k.ctx, ctx->a, ctx->a); \ |
| 313 | plan.from_input -= PRE##_BLKSZ; \ |
| 314 | } \ |
| 315 | \ |
| 316 | /* Finally, deal with any final portion. If there is one, we know \ |
| 317 | * that the buffer is empty: we must have filled it above, or this \ |
| 318 | * would all count as `initial' data. \ |
| 319 | */ \ |
| 320 | if (plan.tail) { \ |
| 321 | pre##_eblk(&ctx->k.ctx, ctx->c, t); BLKC_BSTEP(PRE, ctx->c); \ |
| 322 | BLKC_STORE(PRE, ctx->b, t); \ |
| 323 | r = ctx->b; ctx->off += plan.tail; \ |
| 324 | while (plan.tail--) { y = *p++ ^ *r; *r++ = *q++ = y; } \ |
| 325 | } \ |
| 326 | \ |
| 327 | /* And we're done. */ \ |
| 328 | return (0); \ |
| 329 | } \ |
| 330 | \ |
| 331 | /* --- @pre_eaxdecrypt@ --- * \ |
| 332 | * \ |
| 333 | * Arguments: @pre_eaxctx *ctx@ = pointer to EAX operation context \ |
| 334 | * @const void *src@ = pointer to ciphertext message chunk \ |
| 335 | * @size_t sz@ = size of the ciphertext \ |
| 336 | * @buf *dst@ = a buffer to write the plaintext to \ |
| 337 | * \ |
| 338 | * Returns: Zero on success; @-1@ on failure. \ |
| 339 | * \ |
| 340 | * Use: Decrypts a chunk of a ciphertext message, writing a \ |
| 341 | * chunk of plaintext to the output buffer and updating \ |
| 342 | * the operation state. \ |
| 343 | * \ |
| 344 | * For EAX, we always write a plaintext chunk the same \ |
| 345 | * size as the ciphertext. The messing about with @buf@ \ |
| 346 | * objects makes the interface consistent with other AEAD \ |
| 347 | * schemes which can't do this. \ |
| 348 | */ \ |
| 349 | \ |
| 350 | int pre##_eaxdecrypt(pre##_eaxctx *ctx, \ |
| 351 | const void *src, size_t sz, buf *dst) \ |
| 352 | { \ |
| 353 | rsvr_plan plan; \ |
| 354 | uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ]; \ |
| 355 | const octet *p = src; \ |
| 356 | octet *q, *r, y; \ |
| 357 | \ |
| 358 | /* Allocate space for the plaintext. */ \ |
| 359 | if (sz) { q = buf_get(dst, sz); if (!q) return (-1); } \ |
| 360 | else q = 0; \ |
| 361 | \ |
| 362 | /* Determine the buffering plan. Our buffer is going to do double- \ |
| 363 | * duty here. The end portion is going to contain mask from the \ |
| 364 | * encrypted counter which we mix into the plaintext to encrypt it; \ |
| 365 | * the start portion, which originally contained mask bytes we've \ |
| 366 | * already used, will hold the input ciphertext, which will \ |
| 367 | * eventually be collected into the OMAC state. \ |
| 368 | */ \ |
| 369 | rsvr_mkplan(&plan, &pre##_omacpolicy, ctx->off, sz); \ |
| 370 | \ |
| 371 | /* Initial portion, fulfilled from the buffer. If the buffer is \ |
| 372 | * empty, then that means that we haven't yet encrypted the current \ |
| 373 | * counter, so we should do that and advance it. \ |
| 374 | */ \ |
| 375 | if (plan.head) { \ |
| 376 | if (!ctx->off) { \ |
| 377 | pre##_eblk(&ctx->k.ctx, ctx->c, t); BLKC_BSTEP(PRE, ctx->c); \ |
| 378 | BLKC_STORE(PRE, ctx->b, t); \ |
| 379 | } \ |
| 380 | r = ctx->b + ctx->off; ctx->off += plan.head; \ |
| 381 | while (plan.head--) { y = *p++; *q++ = y ^ *r; *r++ = y; } \ |
| 382 | } \ |
| 383 | \ |
| 384 | /* If we've filled up the buffer then we need to cycle the MAC and \ |
| 385 | * reset the offset. \ |
| 386 | */ \ |
| 387 | if (plan.from_rsvr) { \ |
| 388 | OMAC_BLOCK(PRE, pre, &ctx->k.ctx, ctx->a, ctx->b); \ |
| 389 | ctx->off = 0; \ |
| 390 | } \ |
| 391 | \ |
| 392 | /* Now to process the main body of the input. We sneakily open-code \ |
| 393 | * the OMAC part of this. \ |
| 394 | */ \ |
| 395 | while (plan.from_input) { \ |
| 396 | pre##_eblk(&ctx->k.ctx, ctx->c, t); BLKC_BSTEP(PRE, ctx->c); \ |
| 397 | BLKC_LOAD(PRE, u, p); p += PRE##_BLKSZ; \ |
| 398 | BLKC_XSTORE(PRE, q, t, u); q += PRE##_BLKSZ; \ |
| 399 | BLKC_XMOVE(PRE, ctx->a, u); pre##_eblk(&ctx->k.ctx, ctx->a, ctx->a); \ |
| 400 | plan.from_input -= PRE##_BLKSZ; \ |
| 401 | } \ |
| 402 | \ |
| 403 | /* Finally, deal with any final portion. If there is one, we know \ |
| 404 | * that the buffer is empty: we must have filled it above, or this \ |
| 405 | * would all count as `initial' data. \ |
| 406 | */ \ |
| 407 | if (plan.tail) { \ |
| 408 | pre##_eblk(&ctx->k.ctx, ctx->c, t); BLKC_BSTEP(PRE, ctx->c); \ |
| 409 | BLKC_STORE(PRE, ctx->b, t); \ |
| 410 | r = ctx->b; ctx->off += plan.tail; \ |
| 411 | while (plan.tail--) { y = *p++; *q++ = y ^ *r; *r++ = y; } \ |
| 412 | } \ |
| 413 | \ |
| 414 | /* And we're done. */ \ |
| 415 | return (0); \ |
| 416 | } \ |
| 417 | \ |
| 418 | /* --- @pre_eaxtag@ --- * \ |
| 419 | * \ |
| 420 | * Arguments: @pre_eaxctx *ctx@ = pointer to an EAX context \ |
| 421 | * @const pre_eaxaadctx *aad@ = pointer to AAD context, or \ |
| 422 | * null \ |
| 423 | * @octet *t@ = where to write a (full-length) tag \ |
| 424 | * \ |
| 425 | * Returns: --- \ |
| 426 | * \ |
| 427 | * Use: Finishes an EAX operation, by calculating the tag. \ |
| 428 | */ \ |
| 429 | \ |
| 430 | static void pre##_eaxtag(pre##_eaxctx *ctx, \ |
| 431 | const pre##_eaxaadctx *aad, octet *t) \ |
| 432 | { \ |
| 433 | octet b[PRE##_BLKSZ]; \ |
| 434 | uint32 u[PRE##_BLKSZ/4]; \ |
| 435 | \ |
| 436 | /* Finish tagging the ciphertext. (The buffer is empty if and only \ |
| 437 | * if there was no message, since the OMAC reservoir policy leaves \ |
| 438 | * the buffer full.) \ |
| 439 | */ \ |
| 440 | if (!ctx->off) BLKC_MOVE(PRE, ctx->a, ctx->k.z2); \ |
| 441 | else pre##_omacdone(&ctx->k.ctx, ctx->k.m0, ctx->k.m1, \ |
| 442 | ctx->a, ctx->b, ctx->off); \ |
| 443 | \ |
| 444 | /* If there's no AAD, because the pointer is null or no data was \ |
| 445 | * supplied, then use the cached empty-header tag. Otherwise \ |
| 446 | * calculate the tag for the AAD. Either way, mix the result into \ |
| 447 | * ctx->A, and be careful not to modify the AAD context. (Again, the \ |
| 448 | * buffer is empty if and only if there was no AAD.) \ |
| 449 | */ \ |
| 450 | if (!aad || !aad->off) BLKC_XMOVE(PRE, ctx->a, ctx->k.z1); \ |
| 451 | else { \ |
| 452 | BLKC_MOVE(PRE, u, aad->a); memcpy(b, aad->b, aad->off); \ |
| 453 | pre##_omacdone(&ctx->k.ctx, ctx->k.m0, ctx->k.m1, u, b, aad->off); \ |
| 454 | BLKC_XMOVE(PRE, ctx->a, u); \ |
| 455 | } \ |
| 456 | \ |
| 457 | /* Finally, mix in the initial counter value. */ \ |
| 458 | BLKC_XMOVE(PRE, ctx->a, ctx->c0); \ |
| 459 | \ |
| 460 | /* We're done. */ \ |
| 461 | BLKC_STORE(PRE, t, ctx->a); \ |
| 462 | } \ |
| 463 | \ |
| 464 | /* --- @pre_eaxencryptdone@ --- * \ |
| 465 | * \ |
| 466 | * Arguments: @pre_eaxctx *ctx@ = pointer to an EAX context \ |
| 467 | * @const pre_eaxaadctx *aad@ = pointer to AAD context, or \ |
| 468 | * null \ |
| 469 | * @buf *dst@ = buffer for remaining ciphertext \ |
| 470 | * @void *tag@ = where to write the tag \ |
| 471 | * @size_t tsz@ = length of tag to store \ |
| 472 | * \ |
| 473 | * Returns: Zero on success; @-1@ on failure. \ |
| 474 | * \ |
| 475 | * Use: Completes an EAX encryption operation. The @aad@ \ |
| 476 | * pointer may be null if there is no additional \ |
| 477 | * authenticated data. EAX doesn't buffer ciphertext, but \ |
| 478 | * the output buffer is provided anyway for consistency \ |
| 479 | * with other AEAD schemes which don't have this property; \ |
| 480 | * the function will fail if the output buffer is broken. \ |
| 481 | */ \ |
| 482 | \ |
| 483 | int pre##_eaxencryptdone(pre##_eaxctx *ctx, \ |
| 484 | const pre##_eaxaadctx *aad, buf *dst, \ |
| 485 | void *tag, size_t tsz) \ |
| 486 | { \ |
| 487 | octet t[PRE##_BLKSZ]; \ |
| 488 | \ |
| 489 | if (tsz > PRE##_BLKSZ) return (-1); \ |
| 490 | if (!BOK(dst)) return (-1); \ |
| 491 | pre##_eaxtag(ctx, aad, t); memcpy(tag, t, tsz); \ |
| 492 | return (0); \ |
| 493 | } \ |
| 494 | \ |
| 495 | /* --- @pre_eaxdecryptdone@ --- * \ |
| 496 | * \ |
| 497 | * Arguments: @pre_eaxctx *ctx@ = pointer to an EAX context \ |
| 498 | * @const pre_eaxaadctx *aad@ = pointer to AAD context, or \ |
| 499 | * null \ |
| 500 | * @buf *dst@ = buffer for remaining plaintext \ |
| 501 | * @const void *tag@ = tag to verify \ |
| 502 | * @size_t tsz@ = length of tag \ |
| 503 | * \ |
| 504 | * Returns: @+1@ for complete success; @0@ if tag verification \ |
| 505 | * failed; @-1@ for other kinds of errors. \ |
| 506 | * \ |
| 507 | * Use: Completes an EAX decryption operation. The @aad@ \ |
| 508 | * pointer may be null if there is no additional \ |
| 509 | * authenticated data. EAX doesn't buffer plaintext, but \ |
| 510 | * the output buffer is provided anyway for consistency \ |
| 511 | * with other AEAD schemes which don't have this property; \ |
| 512 | * the function will fail if the output buffer is broken. \ |
| 513 | */ \ |
| 514 | \ |
| 515 | int pre##_eaxdecryptdone(pre##_eaxctx *ctx, \ |
| 516 | const pre##_eaxaadctx *aad, buf *dst, \ |
| 517 | const void *tag, size_t tsz) \ |
| 518 | { \ |
| 519 | octet t[PRE##_BLKSZ]; \ |
| 520 | \ |
| 521 | if (tsz > PRE##_BLKSZ) return (-1); \ |
| 522 | if (!BOK(dst)) return (-1); \ |
| 523 | pre##_eaxtag(ctx, aad, t); \ |
| 524 | if (!ct_memeq(tag, t, tsz)) return (0); \ |
| 525 | else return (+1); \ |
| 526 | } \ |
| 527 | \ |
| 528 | /* --- Generic AEAD interface --- */ \ |
| 529 | \ |
| 530 | typedef struct gactx { \ |
| 531 | gaead_aad a; \ |
| 532 | pre##_eaxaadctx aad; \ |
| 533 | } gactx; \ |
| 534 | \ |
| 535 | \ |
| 536 | static gaead_aad *gadup(const gaead_aad *a) \ |
| 537 | { gactx *aad = S_CREATE(gactx); *aad = *(gactx *)a; return (&aad->a); } \ |
| 538 | \ |
| 539 | static void gahash(gaead_aad *a, const void *h, size_t hsz) \ |
| 540 | { gactx *aad = (gactx *)a; pre##_eaxaadhash(&aad->aad, h, hsz); } \ |
| 541 | \ |
| 542 | static void gadestroy(gaead_aad *a) \ |
| 543 | { gactx *aad = (gactx *)a; BURN(*aad); S_DESTROY(aad); } \ |
| 544 | \ |
| 545 | static const gaead_aadops gaops = \ |
| 546 | { &pre##_eax, gadup, gahash, gadestroy }; \ |
| 547 | \ |
| 548 | static gaead_aad *gaad(const pre##_eaxkey *k) \ |
| 549 | { \ |
| 550 | gactx *aad = S_CREATE(gactx); \ |
| 551 | aad->a.ops = &gaops; \ |
| 552 | pre##_eaxaadinit(&aad->aad, k); \ |
| 553 | return (&aad->a); \ |
| 554 | } \ |
| 555 | \ |
| 556 | typedef struct gectx { \ |
| 557 | gaead_enc e; \ |
| 558 | pre##_eaxctx ctx; \ |
| 559 | } gectx; \ |
| 560 | \ |
| 561 | static gaead_aad *geaad(gaead_enc *e) \ |
| 562 | { gectx *enc = (gectx *)e; return (gaad(&enc->ctx.k)); } \ |
| 563 | \ |
| 564 | static int gereinit(gaead_enc *e, const void *n, size_t nsz, \ |
| 565 | size_t hsz, size_t msz, size_t tsz) \ |
| 566 | { \ |
| 567 | gectx *enc = (gectx *)e; \ |
| 568 | \ |
| 569 | if (tsz > PRE##_BLKSZ) return (-1); \ |
| 570 | pre##_eaxreinit(&enc->ctx, n, nsz); \ |
| 571 | return (0); \ |
| 572 | } \ |
| 573 | \ |
| 574 | static int geenc(gaead_enc *e, const void *m, size_t msz, buf *b) \ |
| 575 | { \ |
| 576 | gectx *enc = (gectx *)e; \ |
| 577 | return (pre##_eaxencrypt(&enc->ctx, m, msz, b)); \ |
| 578 | } \ |
| 579 | \ |
| 580 | static int gedone(gaead_enc *e, const gaead_aad *a, \ |
| 581 | buf *b, void *t, size_t tsz) \ |
| 582 | { \ |
| 583 | gectx *enc = (gectx *)e; gactx *aad = (gactx *)a; \ |
| 584 | assert(!a || a->ops == &gaops); \ |
| 585 | return (pre##_eaxencryptdone(&enc->ctx, a ? &aad->aad : 0, b, t, tsz)); \ |
| 586 | } \ |
| 587 | \ |
| 588 | static void gedestroy(gaead_enc *e) \ |
| 589 | { gectx *enc = (gectx *)e; BURN(*enc); S_DESTROY(enc); } \ |
| 590 | \ |
| 591 | static const gaead_encops geops = \ |
| 592 | { &pre##_eax, geaad, gereinit, geenc, gedone, gedestroy }; \ |
| 593 | \ |
| 594 | typedef struct gdctx { \ |
| 595 | gaead_dec d; \ |
| 596 | pre##_eaxctx ctx; \ |
| 597 | } gdctx; \ |
| 598 | \ |
| 599 | static gaead_aad *gdaad(gaead_dec *d) \ |
| 600 | { gdctx *dec = (gdctx *)d; return (gaad(&dec->ctx.k)); } \ |
| 601 | \ |
| 602 | static int gdreinit(gaead_dec *d, const void *n, size_t nsz, \ |
| 603 | size_t hsz, size_t csz, size_t tsz) \ |
| 604 | { \ |
| 605 | gdctx *dec = (gdctx *)d; \ |
| 606 | \ |
| 607 | if (tsz > PRE##_BLKSZ) return (-1); \ |
| 608 | pre##_eaxreinit(&dec->ctx, n, nsz); \ |
| 609 | return (0); \ |
| 610 | } \ |
| 611 | \ |
| 612 | static int gddec(gaead_dec *d, const void *c, size_t csz, buf *b) \ |
| 613 | { \ |
| 614 | gdctx *dec = (gdctx *)d; \ |
| 615 | return (pre##_eaxdecrypt(&dec->ctx, c, csz, b)); \ |
| 616 | } \ |
| 617 | \ |
| 618 | static int gddone(gaead_dec *d, const gaead_aad *a, \ |
| 619 | buf *b, const void *t, size_t tsz) \ |
| 620 | { \ |
| 621 | gdctx *dec = (gdctx *)d; gactx *aad = (gactx *)a; \ |
| 622 | assert(!a || a->ops == &gaops); \ |
| 623 | return (pre##_eaxdecryptdone(&dec->ctx, a ? &aad->aad : 0, b, t, tsz)); \ |
| 624 | } \ |
| 625 | \ |
| 626 | static void gddestroy(gaead_dec *d) \ |
| 627 | { gdctx *dec = (gdctx *)d; BURN(*dec); S_DESTROY(dec); } \ |
| 628 | \ |
| 629 | static const gaead_decops gdops = \ |
| 630 | { &pre##_eax, gdaad, gdreinit, gddec, gddone, gddestroy }; \ |
| 631 | \ |
| 632 | typedef struct gkctx { \ |
| 633 | gaead_key k; \ |
| 634 | pre##_eaxkey key; \ |
| 635 | } gkctx; \ |
| 636 | \ |
| 637 | static gaead_aad *gkaad(const gaead_key *k) \ |
| 638 | { gkctx *key = (gkctx *)k; return (gaad(&key->key)); } \ |
| 639 | \ |
| 640 | static gaead_enc *gkenc(const gaead_key *k, const void *n, size_t nsz, \ |
| 641 | size_t hsz, size_t msz, size_t tsz) \ |
| 642 | { \ |
| 643 | gkctx *key = (gkctx *)k; \ |
| 644 | gectx *enc; \ |
| 645 | \ |
| 646 | if (tsz > PRE##_BLKSZ) return (0); \ |
| 647 | enc = S_CREATE(gectx); enc->e.ops = &geops; \ |
| 648 | pre##_eaxinit(&enc->ctx, &key->key, n, nsz); \ |
| 649 | return (&enc->e); \ |
| 650 | } \ |
| 651 | \ |
| 652 | static gaead_dec *gkdec(const gaead_key *k, const void *n, size_t nsz, \ |
| 653 | size_t hsz, size_t csz, size_t tsz) \ |
| 654 | { \ |
| 655 | gkctx *key = (gkctx *)k; \ |
| 656 | gdctx *dec; \ |
| 657 | \ |
| 658 | if (tsz > PRE##_BLKSZ) return (0); \ |
| 659 | dec = S_CREATE(gdctx); dec->d.ops = &gdops; \ |
| 660 | pre##_eaxinit(&dec->ctx, &key->key, n, nsz); \ |
| 661 | return (&dec->d); \ |
| 662 | } \ |
| 663 | \ |
| 664 | static void gkdestroy(gaead_key *k) \ |
| 665 | { gkctx *key = (gkctx *)k; BURN(*key); S_DESTROY(key); } \ |
| 666 | \ |
| 667 | static const gaead_keyops gkops = \ |
| 668 | { &pre##_eax, gkaad, gkenc, gkdec, gkdestroy }; \ |
| 669 | \ |
| 670 | static gaead_key *gckey(const void *k, size_t ksz) \ |
| 671 | { \ |
| 672 | gkctx *key = S_CREATE(gkctx); \ |
| 673 | key->k.ops = &gkops; \ |
| 674 | pre##_eaxsetkey(&key->key, k, ksz); \ |
| 675 | return (&key->k); \ |
| 676 | } \ |
| 677 | \ |
| 678 | static int gcszok(size_t nsz, size_t hsz, size_t msz, size_t tsz) \ |
| 679 | { return (gaead_szokcommon(&pre##_eax, nsz, hsz, msz, tsz)); } \ |
| 680 | \ |
| 681 | const gcaead pre##_eax = { \ |
| 682 | name "-eax", \ |
| 683 | pre##_keysz, pre##_eaxnoncesz, pre##_eaxtagsz, \ |
| 684 | PRE##_BLKSZ, 0, 0, 0, \ |
| 685 | gckey, gcszok \ |
| 686 | }; \ |
| 687 | \ |
| 688 | EAX_TESTX(PRE, pre, name, fname) |
| 689 | |
| 690 | /*----- Test rig ----------------------------------------------------------*/ |
| 691 | |
| 692 | #define EAX_TEST(PRE, pre) EAX_TESTX(PRE, pre, #pre, #pre) |
| 693 | |
| 694 | /* --- @EAX_TEST@ --- * |
| 695 | * |
| 696 | * Arguments: @PRE, pre@ = prefixes for the underlying block cipher |
| 697 | * |
| 698 | * Use: Standard test rig for EAX functions. |
| 699 | */ |
| 700 | |
| 701 | #ifdef TEST_RIG |
| 702 | |
| 703 | #include <stdio.h> |
| 704 | |
| 705 | #include <mLib/dstr.h> |
| 706 | #include <mLib/macros.h> |
| 707 | #include <mLib/quis.h> |
| 708 | #include <mLib/testrig.h> |
| 709 | |
| 710 | #define EAX_TESTX(PRE, pre, name, fname) \ |
| 711 | \ |
| 712 | static int eaxverify(dstr *v) \ |
| 713 | { \ |
| 714 | pre##_eaxkey key; \ |
| 715 | pre##_eaxaadctx aad; \ |
| 716 | pre##_eaxctx ctx; \ |
| 717 | int ok = 1, win; \ |
| 718 | int i; \ |
| 719 | octet *p; \ |
| 720 | int szs[] = { 1, 7, 192, -1, 0 }, *ip; \ |
| 721 | size_t hsz, msz; \ |
| 722 | dstr d = DSTR_INIT, t = DSTR_INIT; \ |
| 723 | buf b; \ |
| 724 | \ |
| 725 | dstr_ensure(&d, v[4].len > v[3].len ? v[4].len : v[3].len); \ |
| 726 | dstr_ensure(&t, v[5].len); t.len = v[5].len; \ |
| 727 | \ |
| 728 | pre##_eaxsetkey(&key, v[0].buf, v[0].len); \ |
| 729 | \ |
| 730 | for (ip = szs; *ip; ip++) { \ |
| 731 | \ |
| 732 | pre##_eaxinit(&ctx, &key, (octet *)v[1].buf, v[1].len); \ |
| 733 | \ |
| 734 | i = *ip; \ |
| 735 | hsz = v[2].len; \ |
| 736 | if (i == -1) i = hsz; \ |
| 737 | if (i > hsz) continue; \ |
| 738 | p = (octet *)v[2].buf; \ |
| 739 | pre##_eaxaadinit(&aad, &key); \ |
| 740 | while (hsz) { \ |
| 741 | if (i > hsz) i = hsz; \ |
| 742 | pre##_eaxaadhash(&aad, p, i); \ |
| 743 | p += i; hsz -= i; \ |
| 744 | } \ |
| 745 | \ |
| 746 | buf_init(&b, d.buf, d.sz); \ |
| 747 | i = *ip; \ |
| 748 | msz = v[3].len; \ |
| 749 | if (i == -1) i = msz; \ |
| 750 | if (i > msz) continue; \ |
| 751 | p = (octet *)v[3].buf; \ |
| 752 | while (msz) { \ |
| 753 | if (i > msz) i = msz; \ |
| 754 | if (pre##_eaxencrypt(&ctx, p, i, &b)) { \ |
| 755 | puts("!! eaxencrypt reports failure"); \ |
| 756 | goto fail_enc; \ |
| 757 | } \ |
| 758 | p += i; msz -= i; \ |
| 759 | } \ |
| 760 | \ |
| 761 | if (pre##_eaxencryptdone(&ctx, &aad, &b, (octet *)t.buf, t.len)) { \ |
| 762 | puts("!! eaxencryptdone reports failure"); \ |
| 763 | goto fail_enc; \ |
| 764 | } \ |
| 765 | d.len = BLEN(&b); \ |
| 766 | \ |
| 767 | if (d.len != v[4].len || \ |
| 768 | MEMCMP(d.buf, !=, v[4].buf, v[4].len) || \ |
| 769 | MEMCMP(t.buf, !=, v[5].buf, v[5].len)) { \ |
| 770 | fail_enc: \ |
| 771 | printf("\nfail encrypt:\n\tstep = %i", *ip); \ |
| 772 | fputs("\n\tkey = ", stdout); type_hex.dump(&v[0], stdout); \ |
| 773 | fputs("\n\tnonce = ", stdout); type_hex.dump(&v[1], stdout); \ |
| 774 | fputs("\n\theader = ", stdout); type_hex.dump(&v[2], stdout); \ |
| 775 | fputs("\n\tmessage = ", stdout); type_hex.dump(&v[3], stdout); \ |
| 776 | fputs("\n\texp ct = ", stdout); type_hex.dump(&v[4], stdout); \ |
| 777 | fputs("\n\tcalc ct = ", stdout); type_hex.dump(&d, stdout); \ |
| 778 | fputs("\n\texp tag = ", stdout); type_hex.dump(&v[5], stdout); \ |
| 779 | fputs("\n\tcalc tag = ", stdout); type_hex.dump(&t, stdout); \ |
| 780 | putchar('\n'); \ |
| 781 | ok = 0; \ |
| 782 | } \ |
| 783 | \ |
| 784 | pre##_eaxinit(&ctx, &key, (octet *)v[1].buf, v[1].len); \ |
| 785 | \ |
| 786 | buf_init(&b, d.buf, d.sz); \ |
| 787 | i = *ip; \ |
| 788 | msz = v[4].len; \ |
| 789 | if (i == -1) i = msz; \ |
| 790 | if (i > msz) continue; \ |
| 791 | p = (octet *)v[4].buf; \ |
| 792 | while (msz) { \ |
| 793 | if (i > msz) i = msz; \ |
| 794 | if (pre##_eaxdecrypt(&ctx, p, i, &b)) { \ |
| 795 | puts("!! eaxdecrypt reports failure"); \ |
| 796 | win = 0; goto fail_dec; \ |
| 797 | } \ |
| 798 | p += i; msz -= i; \ |
| 799 | } \ |
| 800 | \ |
| 801 | win = pre##_eaxdecryptdone(&ctx, &aad, &b, \ |
| 802 | (octet *)v[5].buf, v[5].len); \ |
| 803 | if (win < 0) { \ |
| 804 | puts("!! eaxdecryptdone reports failure"); \ |
| 805 | goto fail_dec; \ |
| 806 | } \ |
| 807 | d.len = BLEN(&b); \ |
| 808 | \ |
| 809 | if (d.len != v[3].len || !win || \ |
| 810 | MEMCMP(d.buf, !=, v[3].buf, v[3].len)) { \ |
| 811 | fail_dec: \ |
| 812 | printf("\nfail decrypt:\n\tstep = %i", *ip); \ |
| 813 | fputs("\n\tkey = ", stdout); type_hex.dump(&v[0], stdout); \ |
| 814 | fputs("\n\tnonce = ", stdout); type_hex.dump(&v[1], stdout); \ |
| 815 | fputs("\n\theader = ", stdout); type_hex.dump(&v[2], stdout); \ |
| 816 | fputs("\n\tciphertext = ", stdout); type_hex.dump(&v[4], stdout); \ |
| 817 | fputs("\n\texp pt = ", stdout); type_hex.dump(&v[3], stdout); \ |
| 818 | fputs("\n\tcalc pt = ", stdout); type_hex.dump(&d, stdout); \ |
| 819 | fputs("\n\ttag = ", stdout); type_hex.dump(&v[5], stdout); \ |
| 820 | printf("\n\tverify %s", win ? "ok" : "FAILED"); \ |
| 821 | putchar('\n'); \ |
| 822 | ok = 0; \ |
| 823 | } \ |
| 824 | } \ |
| 825 | \ |
| 826 | dstr_destroy(&d); dstr_destroy(&t); \ |
| 827 | return (ok); \ |
| 828 | } \ |
| 829 | \ |
| 830 | static test_chunk aeaddefs[] = { \ |
| 831 | { name "-eax", eaxverify, \ |
| 832 | { &type_hex, &type_hex, &type_hex, &type_hex, \ |
| 833 | &type_hex, &type_hex, 0 } }, \ |
| 834 | { 0, 0, { 0 } } \ |
| 835 | }; \ |
| 836 | \ |
| 837 | int main(int argc, char *argv[]) \ |
| 838 | { \ |
| 839 | ego(argv[0]); \ |
| 840 | test_run(argc, argv, aeaddefs, SRCDIR"/t/" fname); \ |
| 841 | return (0); \ |
| 842 | } |
| 843 | |
| 844 | #else |
| 845 | # define EAX_TESTX(PRE, pre, name, fname) |
| 846 | #endif |
| 847 | |
| 848 | /*----- That's all, folks -------------------------------------------------*/ |
| 849 | |
| 850 | #ifdef __cplusplus |
| 851 | } |
| 852 | #endif |
| 853 | |
| 854 | #endif |