crypto/aegis128.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * The AEGIS-128 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 AEGIS128_NONCE_SIZE 16
  22 #define AEGIS128_STATE_BLOCKS 5
  23 #define AEGIS128_KEY_SIZE 16
  24 #define AEGIS128_MIN_AUTH_SIZE 8
  25 #define AEGIS128_MAX_AUTH_SIZE 16
  26
  27 struct aegis_state {
  28         union aegis_block blocks[AEGIS128_STATE_BLOCKS];
  29 };
  30
  31 struct aegis_ctx {
  32         union aegis_block key;
  33 };
  34
  35 struct aegis128_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_aegis128_update(struct aegis_state *state)
  44 {
  45         union aegis_block tmp;
  46         unsigned int i;
  47
  48         tmp = state->blocks[AEGIS128_STATE_BLOCKS - 1];
  49         for (i = AEGIS128_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_aegis128_update_a(struct aegis_state *state,
  56                                      const union aegis_block *msg)
  57 {
  58         crypto_aegis128_update(state);
  59         crypto_aegis_block_xor(&state->blocks[0], msg);
  60 }
  61
  62 static void crypto_aegis128_update_u(struct aegis_state *state, const void *msg)
  63 {
  64         crypto_aegis128_update(state);
  65         crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
  66 }
  67
  68 static void crypto_aegis128_init(struct aegis_state *state,
  69                                  const union aegis_block *key,
  70                                  const u8 *iv)
  71 {
  72         union aegis_block key_iv;
  73         unsigned int i;
  74
  75         key_iv = *key;
  76         crypto_xor(key_iv.bytes, iv, AEGIS_BLOCK_SIZE);
  77
  78         state->blocks[0] = key_iv;
  79         state->blocks[1] = crypto_aegis_const[1];
  80         state->blocks[2] = crypto_aegis_const[0];
  81         state->blocks[3] = *key;
  82         state->blocks[4] = *key;
  83
  84         crypto_aegis_block_xor(&state->blocks[3], &crypto_aegis_const[0]);
  85         crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[1]);
  86
  87         for (i = 0; i < 5; i++) {
  88                 crypto_aegis128_update_a(state, key);
  89                 crypto_aegis128_update_a(state, &key_iv);
  90         }
  91 }
  92
  93 static void crypto_aegis128_ad(struct aegis_state *state,
  94                                const u8 *src, unsigned int size)
  95 {
  96         if (AEGIS_ALIGNED(src)) {
  97                 const union aegis_block *src_blk =
  98                                 (const union aegis_block *)src;
  99
 100                 while (size >= AEGIS_BLOCK_SIZE) {
 101                         crypto_aegis128_update_a(state, src_blk);
 102
 103                         size -= AEGIS_BLOCK_SIZE;
 104                         src_blk++;
 105                 }
 106         } else {
 107                 while (size >= AEGIS_BLOCK_SIZE) {
 108                         crypto_aegis128_update_u(state, src);
 109
 110                         size -= AEGIS_BLOCK_SIZE;
 111                         src += AEGIS_BLOCK_SIZE;
 112                 }
 113         }
 114 }
 115
 116 static void crypto_aegis128_encrypt_chunk(struct aegis_state *state, u8 *dst,
 117                                           const u8 *src, unsigned int size)
 118 {
 119         union aegis_block tmp;
 120
 121         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 122                 while (size >= AEGIS_BLOCK_SIZE) {
 123                         union aegis_block *dst_blk =
 124                                         (union aegis_block *)dst;
 125                         const union aegis_block *src_blk =
 126                                         (const union aegis_block *)src;
 127
 128                         tmp = state->blocks[2];
 129                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 130                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 131                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 132                         crypto_aegis_block_xor(&tmp, src_blk);
 133
 134                         crypto_aegis128_update_a(state, src_blk);
 135
 136                         *dst_blk = tmp;
 137
 138                         size -= AEGIS_BLOCK_SIZE;
 139                         src += AEGIS_BLOCK_SIZE;
 140                         dst += AEGIS_BLOCK_SIZE;
 141                 }
 142         } else {
 143                 while (size >= AEGIS_BLOCK_SIZE) {
 144                         tmp = state->blocks[2];
 145                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 146                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 147                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 148                         crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
 149
 150                         crypto_aegis128_update_u(state, src);
 151
 152                         memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
 153
 154                         size -= AEGIS_BLOCK_SIZE;
 155                         src += AEGIS_BLOCK_SIZE;
 156                         dst += AEGIS_BLOCK_SIZE;
 157                 }
 158         }
 159
 160         if (size > 0) {
 161                 union aegis_block msg = {};
 162                 memcpy(msg.bytes, src, size);
 163
 164                 tmp = state->blocks[2];
 165                 crypto_aegis_block_and(&tmp, &state->blocks[3]);
 166                 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 167                 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 168
 169                 crypto_aegis128_update_a(state, &msg);
 170
 171                 crypto_aegis_block_xor(&msg, &tmp);
 172
 173                 memcpy(dst, msg.bytes, size);
 174         }
 175 }
 176
 177 static void crypto_aegis128_decrypt_chunk(struct aegis_state *state, u8 *dst,
 178                                           const u8 *src, unsigned int size)
 179 {
 180         union aegis_block tmp;
 181
 182         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 183                 while (size >= AEGIS_BLOCK_SIZE) {
 184                         union aegis_block *dst_blk =
 185                                         (union aegis_block *)dst;
 186                         const union aegis_block *src_blk =
 187                                         (const union aegis_block *)src;
 188
 189                         tmp = state->blocks[2];
 190                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 191                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 192                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 193                         crypto_aegis_block_xor(&tmp, src_blk);
 194
 195                         crypto_aegis128_update_a(state, &tmp);
 196
 197                         *dst_blk = tmp;
 198
 199                         size -= AEGIS_BLOCK_SIZE;
 200                         src += AEGIS_BLOCK_SIZE;
 201                         dst += AEGIS_BLOCK_SIZE;
 202                 }
 203         } else {
 204                 while (size >= AEGIS_BLOCK_SIZE) {
 205                         tmp = state->blocks[2];
 206                         crypto_aegis_block_and(&tmp, &state->blocks[3]);
 207                         crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 208                         crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 209                         crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
 210
 211                         crypto_aegis128_update_a(state, &tmp);
 212
 213                         memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
 214
 215                         size -= AEGIS_BLOCK_SIZE;
 216                         src += AEGIS_BLOCK_SIZE;
 217                         dst += AEGIS_BLOCK_SIZE;
 218                 }
 219         }
 220
 221         if (size > 0) {
 222                 union aegis_block msg = {};
 223                 memcpy(msg.bytes, src, size);
 224
 225                 tmp = state->blocks[2];
 226                 crypto_aegis_block_and(&tmp, &state->blocks[3]);
 227                 crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 228                 crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 229                 crypto_aegis_block_xor(&msg, &tmp);
 230
 231                 memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);
 232
 233                 crypto_aegis128_update_a(state, &msg);
 234
 235                 memcpy(dst, msg.bytes, size);
 236         }
 237 }
 238
 239 static void crypto_aegis128_process_ad(struct aegis_state *state,
 240                                        struct scatterlist *sg_src,
 241                                        unsigned int assoclen)
 242 {
 243         struct scatter_walk walk;
 244         union aegis_block buf;
 245         unsigned int pos = 0;
 246
 247         scatterwalk_start(&walk, sg_src);
 248         while (assoclen != 0) {
 249                 unsigned int size = scatterwalk_clamp(&walk, assoclen);
 250                 unsigned int left = size;
 251                 void *mapped = scatterwalk_map(&walk);
 252                 const u8 *src = (const u8 *)mapped;
 253
 254                 if (pos + size >= AEGIS_BLOCK_SIZE) {
 255                         if (pos > 0) {
 256                                 unsigned int fill = AEGIS_BLOCK_SIZE - pos;
 257                                 memcpy(buf.bytes + pos, src, fill);
 258                                 crypto_aegis128_update_a(state, &buf);
 259                                 pos = 0;
 260                                 left -= fill;
 261                                 src += fill;
 262                         }
 263
 264                         crypto_aegis128_ad(state, src, left);
 265                         src += left & ~(AEGIS_BLOCK_SIZE - 1);
 266                         left &= AEGIS_BLOCK_SIZE - 1;
 267                 }
 268
 269                 memcpy(buf.bytes + pos, src, left);
 270
 271                 pos += left;
 272                 assoclen -= size;
 273                 scatterwalk_unmap(mapped);
 274                 scatterwalk_advance(&walk, size);
 275                 scatterwalk_done(&walk, 0, assoclen);
 276         }
 277
 278         if (pos > 0) {
 279                 memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
 280                 crypto_aegis128_update_a(state, &buf);
 281         }
 282 }
 283
 284 static void crypto_aegis128_process_crypt(struct aegis_state *state,
 285                                           struct aead_request *req,
 286                                           const struct aegis128_ops *ops)
 287 {
 288         struct skcipher_walk walk;
 289
 290         ops->skcipher_walk_init(&walk, req, false);
 291
 292         while (walk.nbytes) {
 293                 unsigned int nbytes = walk.nbytes;
 294
 295                 if (nbytes < walk.total)
 296                         nbytes = round_down(nbytes, walk.stride);
 297
 298                 ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr,
 299                                  nbytes);
 300
 301                 skcipher_walk_done(&walk, walk.nbytes - nbytes);
 302         }
 303 }
 304
 305 static void crypto_aegis128_final(struct aegis_state *state,
 306                                   union aegis_block *tag_xor,
 307                                   u64 assoclen, u64 cryptlen)
 308 {
 309         u64 assocbits = assoclen * 8;
 310         u64 cryptbits = cryptlen * 8;
 311
 312         union aegis_block tmp;
 313         unsigned int i;
 314
 315         tmp.words64[0] = cpu_to_le64(assocbits);
 316         tmp.words64[1] = cpu_to_le64(cryptbits);
 317
 318         crypto_aegis_block_xor(&tmp, &state->blocks[3]);
 319
 320         for (i = 0; i < 7; i++)
 321                 crypto_aegis128_update_a(state, &tmp);
 322
 323         for (i = 0; i < AEGIS128_STATE_BLOCKS; i++)
 324                 crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
 325 }
 326
 327 static int crypto_aegis128_setkey(struct crypto_aead *aead, const u8 *key,
 328                                   unsigned int keylen)
 329 {
 330         struct aegis_ctx *ctx = crypto_aead_ctx(aead);
 331
 332         if (keylen != AEGIS128_KEY_SIZE) {
 333                 crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
 334                 return -EINVAL;
 335         }
 336
 337         memcpy(ctx->key.bytes, key, AEGIS128_KEY_SIZE);
 338         return 0;
 339 }
 340
 341 static int crypto_aegis128_setauthsize(struct crypto_aead *tfm,
 342                                        unsigned int authsize)
 343 {
 344         if (authsize > AEGIS128_MAX_AUTH_SIZE)
 345                 return -EINVAL;
 346         if (authsize < AEGIS128_MIN_AUTH_SIZE)
 347                 return -EINVAL;
 348         return 0;
 349 }
 350
 351 static void crypto_aegis128_crypt(struct aead_request *req,
 352                                   union aegis_block *tag_xor,
 353                                   unsigned int cryptlen,
 354                                   const struct aegis128_ops *ops)
 355 {
 356         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 357         struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 358         struct aegis_state state;
 359
 360         crypto_aegis128_init(&state, &ctx->key, req->iv);
 361         crypto_aegis128_process_ad(&state, req->src, req->assoclen);
 362         crypto_aegis128_process_crypt(&state, req, ops);
 363         crypto_aegis128_final(&state, tag_xor, req->assoclen, cryptlen);
 364 }
 365
 366 static int crypto_aegis128_encrypt(struct aead_request *req)
 367 {
 368         static const struct aegis128_ops ops = {
 369                 .skcipher_walk_init = skcipher_walk_aead_encrypt,
 370                 .crypt_chunk = crypto_aegis128_encrypt_chunk,
 371         };
 372
 373         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 374         union aegis_block tag = {};
 375         unsigned int authsize = crypto_aead_authsize(tfm);
 376         unsigned int cryptlen = req->cryptlen;
 377
 378         crypto_aegis128_crypt(req, &tag, cryptlen, &ops);
 379
 380         scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
 381                                  authsize, 1);
 382         return 0;
 383 }
 384
 385 static int crypto_aegis128_decrypt(struct aead_request *req)
 386 {
 387         static const struct aegis128_ops ops = {
 388                 .skcipher_walk_init = skcipher_walk_aead_decrypt,
 389                 .crypt_chunk = crypto_aegis128_decrypt_chunk,
 390         };
 391         static const u8 zeros[AEGIS128_MAX_AUTH_SIZE] = {};
 392
 393         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 394         union aegis_block tag;
 395         unsigned int authsize = crypto_aead_authsize(tfm);
 396         unsigned int cryptlen = req->cryptlen - authsize;
 397
 398         scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
 399                                  authsize, 0);
 400
 401         crypto_aegis128_crypt(req, &tag, cryptlen, &ops);
 402
 403         return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
 404 }
 405
 406 static int crypto_aegis128_init_tfm(struct crypto_aead *tfm)
 407 {
 408         return 0;
 409 }
 410
 411 static void crypto_aegis128_exit_tfm(struct crypto_aead *tfm)
 412 {
 413 }
 414
 415 static struct aead_alg crypto_aegis128_alg = {
 416         .setkey = crypto_aegis128_setkey,
 417         .setauthsize = crypto_aegis128_setauthsize,
 418         .encrypt = crypto_aegis128_encrypt,
 419         .decrypt = crypto_aegis128_decrypt,
 420         .init = crypto_aegis128_init_tfm,
 421         .exit = crypto_aegis128_exit_tfm,
 422
 423         .ivsize = AEGIS128_NONCE_SIZE,
 424         .maxauthsize = AEGIS128_MAX_AUTH_SIZE,
 425         .chunksize = AEGIS_BLOCK_SIZE,
 426
 427         .base = {
 428                 .cra_blocksize = 1,
 429                 .cra_ctxsize = sizeof(struct aegis_ctx),
 430                 .cra_alignmask = 0,
 431
 432                 .cra_priority = 100,
 433
 434                 .cra_name = "aegis128",
 435                 .cra_driver_name = "aegis128-generic",
 436
 437                 .cra_module = THIS_MODULE,
 438         }
 439 };
 440
 441 static int __init crypto_aegis128_module_init(void)
 442 {
 443         return crypto_register_aead(&crypto_aegis128_alg);
 444 }
 445
 446 static void __exit crypto_aegis128_module_exit(void)
 447 {
 448         crypto_unregister_aead(&crypto_aegis128_alg);
 449 }
 450
 451 subsys_initcall(crypto_aegis128_module_init);
 452 module_exit(crypto_aegis128_module_exit);
 453
 454 MODULE_LICENSE("GPL");
 455 MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
 456 MODULE_DESCRIPTION("AEGIS-128 AEAD algorithm");
 457 MODULE_ALIAS_CRYPTO("aegis128");
 458 MODULE_ALIAS_CRYPTO("aegis128-generic");