crypto/aegis256.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * The AEGIS-256 Authenticated-Encryption Algorithm
   4  *
   5  * Copyright (c) 2017-2018 Ondrej Mosnacek <omosnacek@gmail.com>
   6  * Copyright (C) 2017-2018 Red Hat, Inc. All rights reserved.
   7  */
   8
   9 #include <crypto/algapi.h>
  10 #include <crypto/internal/aead.h>
  11 #include <crypto/internal/skcipher.h>
  12 #include <crypto/scatterwalk.h>
  13 #include <linux/err.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/scatterlist.h>
  18
  19 #include "aegis.h"
  20
  21 #define AEGIS256_NONCE_SIZE 32
  22 #define AEGIS256_STATE_BLOCKS 6
  23 #define AEGIS256_KEY_SIZE 32
  24 #define AEGIS256_MIN_AUTH_SIZE 8
  25 #define AEGIS256_MAX_AUTH_SIZE 16
  26
  27 struct aegis_state {
  28         union aegis_block blocks[AEGIS256_STATE_BLOCKS];
  29 };
  30
  31 struct aegis_ctx {
  32         union aegis_block key[AEGIS256_KEY_SIZE / AEGIS_BLOCK_SIZE];
  33 };
  34
  35 struct aegis256_ops {
  36         int (*skcipher_walk_init)(struct skcipher_walk *walk,
  37                                   struct aead_request *req, bool atomic);
  38
  39         void (*crypt_chunk)(struct aegis_state *state, u8 *dst,
  40                             const u8 *src, unsigned int size);
  41 };
  42
  43 static void crypto_aegis256_update(struct aegis_state *state)
  44 {
  45         union aegis_block tmp;
  46         unsigned int i;
  47
  48         tmp = state->blocks[AEGIS256_STATE_BLOCKS - 1];
  49         for (i = AEGIS256_STATE_BLOCKS - 1; i > 0; i--)
  50                 crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1],
  51                                     &state->blocks[i]);
  52         crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]);
  53 }
  54
  55 static void crypto_aegis256_update_a(struct aegis_state *state,
  56                                      const union aegis_block *msg)
  57 {
  58         crypto_aegis256_update(state);
  59         crypto_aegis_block_xor(&state->blocks[0], msg);
  60 }
  61
  62 static void crypto_aegis256_update_u(struct aegis_state *state, const void *msg)
  63 {
  64         crypto_aegis256_update(state);
  65         crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
  66 }
  67
  68 static void crypto_aegis256_init(struct aegis_state *state,
  69                                  const union aegis_block *key,
  70                                  const u8 *iv)
  71 {
  72         union aegis_block key_iv[2];
  73         unsigned int i;
  74
  75         key_iv[0] = key[0];
  76         key_iv[1] = key[1];
  77         crypto_xor(key_iv[0].bytes, iv + 0 * AEGIS_BLOCK_SIZE,
  78                         AEGIS_BLOCK_SIZE);
  79         crypto_xor(key_iv[1].bytes, iv + 1 * AEGIS_BLOCK_SIZE,
  80                         AEGIS_BLOCK_SIZE);
  81
  82         state->blocks[0] = key_iv[0];
  83         state->blocks[1] = key_iv[1];
  84         state->blocks[2] = crypto_aegis_const[1];
  85         state->blocks[3] = crypto_aegis_const[0];
  86         state->blocks[4] = key[0];
  87         state->blocks[5] = key[1];
  88
  89         crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[0]);
  90         crypto_aegis_block_xor(&state->blocks[5], &crypto_aegis_const[1]);
  91
  92         for (i = 0; i < 4; i++) {
  93                 crypto_aegis256_update_a(state, &key[0]);
  94                 crypto_aegis256_update_a(state, &key[1]);
  95                 crypto_aegis256_update_a(state, &key_iv[0]);
  96                 crypto_aegis256_update_a(state, &key_iv[1]);
  97         }
  98 }
  99
 100 static void crypto_aegis256_ad(struct aegis_state *state,
 101                                const u8 *src, unsigned int size)
 102 {
 103         if (AEGIS_ALIGNED(src)) {
 104                 const union aegis_block *src_blk =
 105                                 (const union aegis_block *)src;
 106
 107                 while (size >= AEGIS_BLOCK_SIZE) {
 108                         crypto_aegis256_update_a(state, src_blk);
 109
 110                         size -= AEGIS_BLOCK_SIZE;
 111                         src_blk++;
 112                 }
 113         } else {
 114                 while (size >= AEGIS_BLOCK_SIZE) {
 115                         crypto_aegis256_update_u(state, src);
 116
 117                         size -= AEGIS_BLOCK_SIZE;
 118                         src += AEGIS_BLOCK_SIZE;
 119                 }
 120         }
 121 }
 122
 123 static void crypto_aegis256_encrypt_chunk(struct aegis_state *state, u8 *dst,
 124                                           const u8 *src, unsigned int size)
 125 {
 126         union aegis_block tmp;
 127
 128         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 129                 while (size >= AEGIS_BLOCK_SIZE) {
 130                         union aegis_block *dst_blk =
 131                                         (union aegis_block *)dst;
 132                         const union aegis_block *src_blk =
 133                                         (const union aegis_block *)src;
 134
 135                         tmp = state->blocks[2];
 136                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 137                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
 138                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 139                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 140                         crypto_aegis_block_xor(&tmp, src_blk);
 141
 142                         crypto_aegis256_update_a(state, src_blk);
 143
 144                         *dst_blk = tmp;
 145
 146                         size -= AEGIS_BLOCK_SIZE;
 147                         src += AEGIS_BLOCK_SIZE;
 148                         dst += AEGIS_BLOCK_SIZE;
 149                 }
 150         } else {
 151                 while (size >= AEGIS_BLOCK_SIZE) {
 152                         tmp = state->blocks[2];
 153                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 154                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
 155                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 156                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 157                         crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
 158
 159                         crypto_aegis256_update_u(state, src);
 160
 161                         memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
 162
 163                         size -= AEGIS_BLOCK_SIZE;
 164                         src += AEGIS_BLOCK_SIZE;
 165                         dst += AEGIS_BLOCK_SIZE;
 166                 }
 167         }
 168
 169         if (size > 0) {
 170                 union aegis_block msg = {};
 171                 memcpy(msg.bytes, src, size);
 172
 173                 tmp = state->blocks[2];
 174                 crypto_aegis_block_and(&tmp, &state->blocks[3]);
 175                 crypto_aegis_block_xor(&tmp, &state->blocks[5]);
 176                 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 177                 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 178
 179                 crypto_aegis256_update_a(state, &msg);
 180
 181                 crypto_aegis_block_xor(&msg, &tmp);
 182
 183                 memcpy(dst, msg.bytes, size);
 184         }
 185 }
 186
 187 static void crypto_aegis256_decrypt_chunk(struct aegis_state *state, u8 *dst,
 188                                           const u8 *src, unsigned int size)
 189 {
 190         union aegis_block tmp;
 191
 192         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 193                 while (size >= AEGIS_BLOCK_SIZE) {
 194                         union aegis_block *dst_blk =
 195                                         (union aegis_block *)dst;
 196                         const union aegis_block *src_blk =
 197                                         (const union aegis_block *)src;
 198
 199                         tmp = state->blocks[2];
 200                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 201                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
 202                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 203                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 204                         crypto_aegis_block_xor(&tmp, src_blk);
 205
 206                         crypto_aegis256_update_a(state, &tmp);
 207
 208                         *dst_blk = tmp;
 209
 210                         size -= AEGIS_BLOCK_SIZE;
 211                         src += AEGIS_BLOCK_SIZE;
 212                         dst += AEGIS_BLOCK_SIZE;
 213                 }
 214         } else {
 215                 while (size >= AEGIS_BLOCK_SIZE) {
 216                         tmp = state->blocks[2];
 217                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 218                         crypto_aegis_block_xor(&tmp, &state->blocks[5]);
 219                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 220                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 221                         crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
 222
 223                         crypto_aegis256_update_a(state, &tmp);
 224
 225                         memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
 226
 227                         size -= AEGIS_BLOCK_SIZE;
 228                         src += AEGIS_BLOCK_SIZE;
 229                         dst += AEGIS_BLOCK_SIZE;
 230                 }
 231         }
 232
 233         if (size > 0) {
 234                 union aegis_block msg = {};
 235                 memcpy(msg.bytes, src, size);
 236
 237                 tmp = state->blocks[2];
 238                 crypto_aegis_block_and(&tmp, &state->blocks[3]);
 239                 crypto_aegis_block_xor(&tmp, &state->blocks[5]);
 240                 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 241                 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 242                 crypto_aegis_block_xor(&msg, &tmp);
 243
 244                 memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);
 245
 246                 crypto_aegis256_update_a(state, &msg);
 247
 248                 memcpy(dst, msg.bytes, size);
 249         }
 250 }
 251
 252 static void crypto_aegis256_process_ad(struct aegis_state *state,
 253                                        struct scatterlist *sg_src,
 254                                        unsigned int assoclen)
 255 {
 256         struct scatter_walk walk;
 257         union aegis_block buf;
 258         unsigned int pos = 0;
 259
 260         scatterwalk_start(&walk, sg_src);
 261         while (assoclen != 0) {
 262                 unsigned int size = scatterwalk_clamp(&walk, assoclen);
 263                 unsigned int left = size;
 264                 void *mapped = scatterwalk_map(&walk);
 265                 const u8 *src = (const u8 *)mapped;
 266
 267                 if (pos + size >= AEGIS_BLOCK_SIZE) {
 268                         if (pos > 0) {
 269                                 unsigned int fill = AEGIS_BLOCK_SIZE - pos;
 270                                 memcpy(buf.bytes + pos, src, fill);
 271                                 crypto_aegis256_update_a(state, &buf);
 272                                 pos = 0;
 273                                 left -= fill;
 274                                 src += fill;
 275                         }
 276
 277                         crypto_aegis256_ad(state, src, left);
 278                         src += left & ~(AEGIS_BLOCK_SIZE - 1);
 279                         left &= AEGIS_BLOCK_SIZE - 1;
 280                 }
 281
 282                 memcpy(buf.bytes + pos, src, left);
 283
 284                 pos += left;
 285                 assoclen -= size;
 286                 scatterwalk_unmap(mapped);
 287                 scatterwalk_advance(&walk, size);
 288                 scatterwalk_done(&walk, 0, assoclen);
 289         }
 290
 291         if (pos > 0) {
 292                 memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
 293                 crypto_aegis256_update_a(state, &buf);
 294         }
 295 }
 296
 297 static void crypto_aegis256_process_crypt(struct aegis_state *state,
 298                                           struct aead_request *req,
 299                                           const struct aegis256_ops *ops)
 300 {
 301         struct skcipher_walk walk;
 302
 303         ops->skcipher_walk_init(&walk, req, false);
 304
 305         while (walk.nbytes) {
 306                 unsigned int nbytes = walk.nbytes;
 307
 308                 if (nbytes < walk.total)
 309                         nbytes = round_down(nbytes, walk.stride);
 310
 311                 ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr,
 312                                  nbytes);
 313
 314                 skcipher_walk_done(&walk, walk.nbytes - nbytes);
 315         }
 316 }
 317
 318 static void crypto_aegis256_final(struct aegis_state *state,
 319                                   union aegis_block *tag_xor,
 320                                   u64 assoclen, u64 cryptlen)
 321 {
 322         u64 assocbits = assoclen * 8;
 323         u64 cryptbits = cryptlen * 8;
 324
 325         union aegis_block tmp;
 326         unsigned int i;
 327
 328         tmp.words64[0] = cpu_to_le64(assocbits);
 329         tmp.words64[1] = cpu_to_le64(cryptbits);
 330
 331         crypto_aegis_block_xor(&tmp, &state->blocks[3]);
 332
 333         for (i = 0; i < 7; i++)
 334                 crypto_aegis256_update_a(state, &tmp);
 335
 336         for (i = 0; i < AEGIS256_STATE_BLOCKS; i++)
 337                 crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
 338 }
 339
 340 static int crypto_aegis256_setkey(struct crypto_aead *aead, const u8 *key,
 341                                   unsigned int keylen)
 342 {
 343         struct aegis_ctx *ctx = crypto_aead_ctx(aead);
 344
 345         if (keylen != AEGIS256_KEY_SIZE) {
 346                 crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
 347                 return -EINVAL;
 348         }
 349
 350         memcpy(ctx->key[0].bytes, key, AEGIS_BLOCK_SIZE);
 351         memcpy(ctx->key[1].bytes, key + AEGIS_BLOCK_SIZE,
 352                         AEGIS_BLOCK_SIZE);
 353         return 0;
 354 }
 355
 356 static int crypto_aegis256_setauthsize(struct crypto_aead *tfm,
 357                                        unsigned int authsize)
 358 {
 359         if (authsize > AEGIS256_MAX_AUTH_SIZE)
 360                 return -EINVAL;
 361         if (authsize < AEGIS256_MIN_AUTH_SIZE)
 362                 return -EINVAL;
 363         return 0;
 364 }
 365
 366 static void crypto_aegis256_crypt(struct aead_request *req,
 367                                   union aegis_block *tag_xor,
 368                                   unsigned int cryptlen,
 369                                   const struct aegis256_ops *ops)
 370 {
 371         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 372         struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 373         struct aegis_state state;
 374
 375         crypto_aegis256_init(&state, ctx->key, req->iv);
 376         crypto_aegis256_process_ad(&state, req->src, req->assoclen);
 377         crypto_aegis256_process_crypt(&state, req, ops);
 378         crypto_aegis256_final(&state, tag_xor, req->assoclen, cryptlen);
 379 }
 380
 381 static int crypto_aegis256_encrypt(struct aead_request *req)
 382 {
 383         static const struct aegis256_ops ops = {
 384                 .skcipher_walk_init = skcipher_walk_aead_encrypt,
 385                 .crypt_chunk = crypto_aegis256_encrypt_chunk,
 386         };
 387
 388         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 389         union aegis_block tag = {};
 390         unsigned int authsize = crypto_aead_authsize(tfm);
 391         unsigned int cryptlen = req->cryptlen;
 392
 393         crypto_aegis256_crypt(req, &tag, cryptlen, &ops);
 394
 395         scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
 396                                  authsize, 1);
 397         return 0;
 398 }
 399
 400 static int crypto_aegis256_decrypt(struct aead_request *req)
 401 {
 402         static const struct aegis256_ops ops = {
 403                 .skcipher_walk_init = skcipher_walk_aead_decrypt,
 404                 .crypt_chunk = crypto_aegis256_decrypt_chunk,
 405         };
 406         static const u8 zeros[AEGIS256_MAX_AUTH_SIZE] = {};
 407
 408         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 409         union aegis_block tag;
 410         unsigned int authsize = crypto_aead_authsize(tfm);
 411         unsigned int cryptlen = req->cryptlen - authsize;
 412
 413         scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
 414                                  authsize, 0);
 415
 416         crypto_aegis256_crypt(req, &tag, cryptlen, &ops);
 417
 418         return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
 419 }
 420
 421 static int crypto_aegis256_init_tfm(struct crypto_aead *tfm)
 422 {
 423         return 0;
 424 }
 425
 426 static void crypto_aegis256_exit_tfm(struct crypto_aead *tfm)
 427 {
 428 }
 429
 430 static struct aead_alg crypto_aegis256_alg = {
 431         .setkey = crypto_aegis256_setkey,
 432         .setauthsize = crypto_aegis256_setauthsize,
 433         .encrypt = crypto_aegis256_encrypt,
 434         .decrypt = crypto_aegis256_decrypt,
 435         .init = crypto_aegis256_init_tfm,
 436         .exit = crypto_aegis256_exit_tfm,
 437
 438         .ivsize = AEGIS256_NONCE_SIZE,
 439         .maxauthsize = AEGIS256_MAX_AUTH_SIZE,
 440         .chunksize = AEGIS_BLOCK_SIZE,
 441
 442         .base = {
 443                 .cra_blocksize = 1,
 444                 .cra_ctxsize = sizeof(struct aegis_ctx),
 445                 .cra_alignmask = 0,
 446
 447                 .cra_priority = 100,
 448
 449                 .cra_name = "aegis256",
 450                 .cra_driver_name = "aegis256-generic",
 451
 452                 .cra_module = THIS_MODULE,
 453         }
 454 };
 455
 456 static int __init crypto_aegis256_module_init(void)
 457 {
 458         return crypto_register_aead(&crypto_aegis256_alg);
 459 }
 460
 461 static void __exit crypto_aegis256_module_exit(void)
 462 {
 463         crypto_unregister_aead(&crypto_aegis256_alg);
 464 }
 465
 466 module_init(crypto_aegis256_module_init);
 467 module_exit(crypto_aegis256_module_exit);
 468
 469 MODULE_LICENSE("GPL");
 470 MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
 471 MODULE_DESCRIPTION("AEGIS-256 AEAD algorithm");
 472 MODULE_ALIAS_CRYPTO("aegis256");
 473 MODULE_ALIAS_CRYPTO("aegis256-generic");