crypto/aegis128l.c

   1 /*
   2  * The AEGIS-128L Authenticated-Encryption Algorithm
   3  *
   4  * Copyright (c) 2017-2018 Ondrej Mosnacek <omosnacek@gmail.com>
   5  * Copyright (C) 2017-2018 Red Hat, Inc. All rights reserved.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License as published by the Free
   9  * Software Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  */
  12
  13 #include <crypto/algapi.h>
  14 #include <crypto/internal/aead.h>
  15 #include <crypto/internal/skcipher.h>
  16 #include <crypto/scatterwalk.h>
  17 #include <linux/err.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/scatterlist.h>
  22
  23 #include "aegis.h"
  24
  25 #define AEGIS128L_CHUNK_BLOCKS 2
  26 #define AEGIS128L_CHUNK_SIZE (AEGIS128L_CHUNK_BLOCKS * AEGIS_BLOCK_SIZE)
  27 #define AEGIS128L_NONCE_SIZE 16
  28 #define AEGIS128L_STATE_BLOCKS 8
  29 #define AEGIS128L_KEY_SIZE 16
  30 #define AEGIS128L_MIN_AUTH_SIZE 8
  31 #define AEGIS128L_MAX_AUTH_SIZE 16
  32
  33 union aegis_chunk {
  34         union aegis_block blocks[AEGIS128L_CHUNK_BLOCKS];
  35         u8 bytes[AEGIS128L_CHUNK_SIZE];
  36 };
  37
  38 struct aegis_state {
  39         union aegis_block blocks[AEGIS128L_STATE_BLOCKS];
  40 };
  41
  42 struct aegis_ctx {
  43         union aegis_block key;
  44 };
  45
  46 struct aegis128l_ops {
  47         int (*skcipher_walk_init)(struct skcipher_walk *walk,
  48                                   struct aead_request *req, bool atomic);
  49
  50         void (*crypt_chunk)(struct aegis_state *state, u8 *dst,
  51                             const u8 *src, unsigned int size);
  52 };
  53
  54 static void crypto_aegis128l_update(struct aegis_state *state)
  55 {
  56         union aegis_block tmp;
  57         unsigned int i;
  58
  59         tmp = state->blocks[AEGIS128L_STATE_BLOCKS - 1];
  60         for (i = AEGIS128L_STATE_BLOCKS - 1; i > 0; i--)
  61                 crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1],
  62                                     &state->blocks[i]);
  63         crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]);
  64 }
  65
  66 static void crypto_aegis128l_update_a(struct aegis_state *state,
  67                                       const union aegis_chunk *msg)
  68 {
  69         crypto_aegis128l_update(state);
  70         crypto_aegis_block_xor(&state->blocks[0], &msg->blocks[0]);
  71         crypto_aegis_block_xor(&state->blocks[4], &msg->blocks[1]);
  72 }
  73
  74 static void crypto_aegis128l_update_u(struct aegis_state *state,
  75                                       const void *msg)
  76 {
  77         crypto_aegis128l_update(state);
  78         crypto_xor(state->blocks[0].bytes, msg + 0 * AEGIS_BLOCK_SIZE,
  79                         AEGIS_BLOCK_SIZE);
  80         crypto_xor(state->blocks[4].bytes, msg + 1 * AEGIS_BLOCK_SIZE,
  81                         AEGIS_BLOCK_SIZE);
  82 }
  83
  84 static void crypto_aegis128l_init(struct aegis_state *state,
  85                                   const union aegis_block *key,
  86                                   const u8 *iv)
  87 {
  88         union aegis_block key_iv;
  89         union aegis_chunk chunk;
  90         unsigned int i;
  91
  92         memcpy(chunk.blocks[0].bytes, iv, AEGIS_BLOCK_SIZE);
  93         chunk.blocks[1] = *key;
  94
  95         key_iv = *key;
  96         crypto_aegis_block_xor(&key_iv, &chunk.blocks[0]);
  97
  98         state->blocks[0] = key_iv;
  99         state->blocks[1] = crypto_aegis_const[1];
 100         state->blocks[2] = crypto_aegis_const[0];
 101         state->blocks[3] = crypto_aegis_const[1];
 102         state->blocks[4] = key_iv;
 103         state->blocks[5] = *key;
 104         state->blocks[6] = *key;
 105         state->blocks[7] = *key;
 106
 107         crypto_aegis_block_xor(&state->blocks[5], &crypto_aegis_const[0]);
 108         crypto_aegis_block_xor(&state->blocks[6], &crypto_aegis_const[1]);
 109         crypto_aegis_block_xor(&state->blocks[7], &crypto_aegis_const[0]);
 110
 111         for (i = 0; i < 10; i++) {
 112                 crypto_aegis128l_update_a(state, &chunk);
 113         }
 114 }
 115
 116 static void crypto_aegis128l_ad(struct aegis_state *state,
 117                                 const u8 *src, unsigned int size)
 118 {
 119         if (AEGIS_ALIGNED(src)) {
 120                 const union aegis_chunk *src_chunk =
 121                                 (const union aegis_chunk *)src;
 122
 123                 while (size >= AEGIS128L_CHUNK_SIZE) {
 124                         crypto_aegis128l_update_a(state, src_chunk);
 125
 126                         size -= AEGIS128L_CHUNK_SIZE;
 127                         src_chunk += 1;
 128                 }
 129         } else {
 130                 while (size >= AEGIS128L_CHUNK_SIZE) {
 131                         crypto_aegis128l_update_u(state, src);
 132
 133                         size -= AEGIS128L_CHUNK_SIZE;
 134                         src += AEGIS128L_CHUNK_SIZE;
 135                 }
 136         }
 137 }
 138
 139 static void crypto_aegis128l_encrypt_chunk(struct aegis_state *state, u8 *dst,
 140                                            const u8 *src, unsigned int size)
 141 {
 142         union aegis_chunk tmp;
 143         union aegis_block *tmp0 = &tmp.blocks[0];
 144         union aegis_block *tmp1 = &tmp.blocks[1];
 145
 146         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 147                 while (size >= AEGIS128L_CHUNK_SIZE) {
 148                         union aegis_chunk *dst_blk =
 149                                         (union aegis_chunk *)dst;
 150                         const union aegis_chunk *src_blk =
 151                                         (const union aegis_chunk *)src;
 152
 153                         *tmp0 = state->blocks[2];
 154                         crypto_aegis_block_and(tmp0, &state->blocks[3]);
 155                         crypto_aegis_block_xor(tmp0, &state->blocks[6]);
 156                         crypto_aegis_block_xor(tmp0, &state->blocks[1]);
 157                         crypto_aegis_block_xor(tmp0, &src_blk->blocks[0]);
 158
 159                         *tmp1 = state->blocks[6];
 160                         crypto_aegis_block_and(tmp1, &state->blocks[7]);
 161                         crypto_aegis_block_xor(tmp1, &state->blocks[5]);
 162                         crypto_aegis_block_xor(tmp1, &state->blocks[2]);
 163                         crypto_aegis_block_xor(tmp1, &src_blk->blocks[1]);
 164
 165                         crypto_aegis128l_update_a(state, src_blk);
 166
 167                         *dst_blk = tmp;
 168
 169                         size -= AEGIS128L_CHUNK_SIZE;
 170                         src += AEGIS128L_CHUNK_SIZE;
 171                         dst += AEGIS128L_CHUNK_SIZE;
 172                 }
 173         } else {
 174                 while (size >= AEGIS128L_CHUNK_SIZE) {
 175                         *tmp0 = state->blocks[2];
 176                         crypto_aegis_block_and(tmp0, &state->blocks[3]);
 177                         crypto_aegis_block_xor(tmp0, &state->blocks[6]);
 178                         crypto_aegis_block_xor(tmp0, &state->blocks[1]);
 179                         crypto_xor(tmp0->bytes, src + 0 * AEGIS_BLOCK_SIZE,
 180                                    AEGIS_BLOCK_SIZE);
 181
 182                         *tmp1 = state->blocks[6];
 183                         crypto_aegis_block_and(tmp1, &state->blocks[7]);
 184                         crypto_aegis_block_xor(tmp1, &state->blocks[5]);
 185                         crypto_aegis_block_xor(tmp1, &state->blocks[2]);
 186                         crypto_xor(tmp1->bytes, src + 1 * AEGIS_BLOCK_SIZE,
 187                                    AEGIS_BLOCK_SIZE);
 188
 189                         crypto_aegis128l_update_u(state, src);
 190
 191                         memcpy(dst, tmp.bytes, AEGIS128L_CHUNK_SIZE);
 192
 193                         size -= AEGIS128L_CHUNK_SIZE;
 194                         src += AEGIS128L_CHUNK_SIZE;
 195                         dst += AEGIS128L_CHUNK_SIZE;
 196                 }
 197         }
 198
 199         if (size > 0) {
 200                 union aegis_chunk msg = {};
 201                 memcpy(msg.bytes, src, size);
 202
 203                 *tmp0 = state->blocks[2];
 204                 crypto_aegis_block_and(tmp0, &state->blocks[3]);
 205                 crypto_aegis_block_xor(tmp0, &state->blocks[6]);
 206                 crypto_aegis_block_xor(tmp0, &state->blocks[1]);
 207
 208                 *tmp1 = state->blocks[6];
 209                 crypto_aegis_block_and(tmp1, &state->blocks[7]);
 210                 crypto_aegis_block_xor(tmp1, &state->blocks[5]);
 211                 crypto_aegis_block_xor(tmp1, &state->blocks[2]);
 212
 213                 crypto_aegis128l_update_a(state, &msg);
 214
 215                 crypto_aegis_block_xor(&msg.blocks[0], tmp0);
 216                 crypto_aegis_block_xor(&msg.blocks[1], tmp1);
 217
 218                 memcpy(dst, msg.bytes, size);
 219         }
 220 }
 221
 222 static void crypto_aegis128l_decrypt_chunk(struct aegis_state *state, u8 *dst,
 223                                            const u8 *src, unsigned int size)
 224 {
 225         union aegis_chunk tmp;
 226         union aegis_block *tmp0 = &tmp.blocks[0];
 227         union aegis_block *tmp1 = &tmp.blocks[1];
 228
 229         if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 230                 while (size >= AEGIS128L_CHUNK_SIZE) {
 231                         union aegis_chunk *dst_blk =
 232                                         (union aegis_chunk *)dst;
 233                         const union aegis_chunk *src_blk =
 234                                         (const union aegis_chunk *)src;
 235
 236                         *tmp0 = state->blocks[2];
 237                         crypto_aegis_block_and(tmp0, &state->blocks[3]);
 238                         crypto_aegis_block_xor(tmp0, &state->blocks[6]);
 239                         crypto_aegis_block_xor(tmp0, &state->blocks[1]);
 240                         crypto_aegis_block_xor(tmp0, &src_blk->blocks[0]);
 241
 242                         *tmp1 = state->blocks[6];
 243                         crypto_aegis_block_and(tmp1, &state->blocks[7]);
 244                         crypto_aegis_block_xor(tmp1, &state->blocks[5]);
 245                         crypto_aegis_block_xor(tmp1, &state->blocks[2]);
 246                         crypto_aegis_block_xor(tmp1, &src_blk->blocks[1]);
 247
 248                         crypto_aegis128l_update_a(state, &tmp);
 249
 250                         *dst_blk = tmp;
 251
 252                         size -= AEGIS128L_CHUNK_SIZE;
 253                         src += AEGIS128L_CHUNK_SIZE;
 254                         dst += AEGIS128L_CHUNK_SIZE;
 255                 }
 256         } else {
 257                 while (size >= AEGIS128L_CHUNK_SIZE) {
 258                         *tmp0 = state->blocks[2];
 259                         crypto_aegis_block_and(tmp0, &state->blocks[3]);
 260                         crypto_aegis_block_xor(tmp0, &state->blocks[6]);
 261                         crypto_aegis_block_xor(tmp0, &state->blocks[1]);
 262                         crypto_xor(tmp0->bytes, src + 0 * AEGIS_BLOCK_SIZE,
 263                                    AEGIS_BLOCK_SIZE);
 264
 265                         *tmp1 = state->blocks[6];
 266                         crypto_aegis_block_and(tmp1, &state->blocks[7]);
 267                         crypto_aegis_block_xor(tmp1, &state->blocks[5]);
 268                         crypto_aegis_block_xor(tmp1, &state->blocks[2]);
 269                         crypto_xor(tmp1->bytes, src + 1 * AEGIS_BLOCK_SIZE,
 270                                    AEGIS_BLOCK_SIZE);
 271
 272                         crypto_aegis128l_update_a(state, &tmp);
 273
 274                         memcpy(dst, tmp.bytes, AEGIS128L_CHUNK_SIZE);
 275
 276                         size -= AEGIS128L_CHUNK_SIZE;
 277                         src += AEGIS128L_CHUNK_SIZE;
 278                         dst += AEGIS128L_CHUNK_SIZE;
 279                 }
 280         }
 281
 282         if (size > 0) {
 283                 union aegis_chunk msg = {};
 284                 memcpy(msg.bytes, src, size);
 285
 286                 *tmp0 = state->blocks[2];
 287                 crypto_aegis_block_and(tmp0, &state->blocks[3]);
 288                 crypto_aegis_block_xor(tmp0, &state->blocks[6]);
 289                 crypto_aegis_block_xor(tmp0, &state->blocks[1]);
 290                 crypto_aegis_block_xor(&msg.blocks[0], tmp0);
 291
 292                 *tmp1 = state->blocks[6];
 293                 crypto_aegis_block_and(tmp1, &state->blocks[7]);
 294                 crypto_aegis_block_xor(tmp1, &state->blocks[5]);
 295                 crypto_aegis_block_xor(tmp1, &state->blocks[2]);
 296                 crypto_aegis_block_xor(&msg.blocks[1], tmp1);
 297
 298                 memset(msg.bytes + size, 0, AEGIS128L_CHUNK_SIZE - size);
 299
 300                 crypto_aegis128l_update_a(state, &msg);
 301
 302                 memcpy(dst, msg.bytes, size);
 303         }
 304 }
 305
 306 static void crypto_aegis128l_process_ad(struct aegis_state *state,
 307                                         struct scatterlist *sg_src,
 308                                         unsigned int assoclen)
 309 {
 310         struct scatter_walk walk;
 311         union aegis_chunk buf;
 312         unsigned int pos = 0;
 313
 314         scatterwalk_start(&walk, sg_src);
 315         while (assoclen != 0) {
 316                 unsigned int size = scatterwalk_clamp(&walk, assoclen);
 317                 unsigned int left = size;
 318                 void *mapped = scatterwalk_map(&walk);
 319                 const u8 *src = (const u8 *)mapped;
 320
 321                 if (pos + size >= AEGIS128L_CHUNK_SIZE) {
 322                         if (pos > 0) {
 323                                 unsigned int fill = AEGIS128L_CHUNK_SIZE - pos;
 324                                 memcpy(buf.bytes + pos, src, fill);
 325                                 crypto_aegis128l_update_a(state, &buf);
 326                                 pos = 0;
 327                                 left -= fill;
 328                                 src += fill;
 329                         }
 330
 331                         crypto_aegis128l_ad(state, src, left);
 332                         src += left & ~(AEGIS128L_CHUNK_SIZE - 1);
 333                         left &= AEGIS128L_CHUNK_SIZE - 1;
 334                 }
 335
 336                 memcpy(buf.bytes + pos, src, left);
 337
 338                 pos += left;
 339                 assoclen -= size;
 340                 scatterwalk_unmap(mapped);
 341                 scatterwalk_advance(&walk, size);
 342                 scatterwalk_done(&walk, 0, assoclen);
 343         }
 344
 345         if (pos > 0) {
 346                 memset(buf.bytes + pos, 0, AEGIS128L_CHUNK_SIZE - pos);
 347                 crypto_aegis128l_update_a(state, &buf);
 348         }
 349 }
 350
 351 static void crypto_aegis128l_process_crypt(struct aegis_state *state,
 352                                            struct aead_request *req,
 353                                            const struct aegis128l_ops *ops)
 354 {
 355         struct skcipher_walk walk;
 356
 357         ops->skcipher_walk_init(&walk, req, false);
 358
 359         while (walk.nbytes) {
 360                 unsigned int nbytes = walk.nbytes;
 361
 362                 if (nbytes < walk.total)
 363                         nbytes = round_down(nbytes, walk.stride);
 364
 365                 ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr,
 366                                  nbytes);
 367
 368                 skcipher_walk_done(&walk, walk.nbytes - nbytes);
 369         }
 370 }
 371
 372 static void crypto_aegis128l_final(struct aegis_state *state,
 373                                    union aegis_block *tag_xor,
 374                                    u64 assoclen, u64 cryptlen)
 375 {
 376         u64 assocbits = assoclen * 8;
 377         u64 cryptbits = cryptlen * 8;
 378
 379         union aegis_chunk tmp;
 380         unsigned int i;
 381
 382         tmp.blocks[0].words64[0] = cpu_to_le64(assocbits);
 383         tmp.blocks[0].words64[1] = cpu_to_le64(cryptbits);
 384
 385         crypto_aegis_block_xor(&tmp.blocks[0], &state->blocks[2]);
 386
 387         tmp.blocks[1] = tmp.blocks[0];
 388         for (i = 0; i < 7; i++)
 389                 crypto_aegis128l_update_a(state, &tmp);
 390
 391         for (i = 0; i < 7; i++)
 392                 crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
 393 }
 394
 395 static int crypto_aegis128l_setkey(struct crypto_aead *aead, const u8 *key,
 396                                    unsigned int keylen)
 397 {
 398         struct aegis_ctx *ctx = crypto_aead_ctx(aead);
 399
 400         if (keylen != AEGIS128L_KEY_SIZE) {
 401                 crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN);
 402                 return -EINVAL;
 403         }
 404
 405         memcpy(ctx->key.bytes, key, AEGIS128L_KEY_SIZE);
 406         return 0;
 407 }
 408
 409 static int crypto_aegis128l_setauthsize(struct crypto_aead *tfm,
 410                                         unsigned int authsize)
 411 {
 412         if (authsize > AEGIS128L_MAX_AUTH_SIZE)
 413                 return -EINVAL;
 414         if (authsize < AEGIS128L_MIN_AUTH_SIZE)
 415                 return -EINVAL;
 416         return 0;
 417 }
 418
 419 static void crypto_aegis128l_crypt(struct aead_request *req,
 420                                    union aegis_block *tag_xor,
 421                                    unsigned int cryptlen,
 422                                    const struct aegis128l_ops *ops)
 423 {
 424         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 425         struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 426         struct aegis_state state;
 427
 428         crypto_aegis128l_init(&state, &ctx->key, req->iv);
 429         crypto_aegis128l_process_ad(&state, req->src, req->assoclen);
 430         crypto_aegis128l_process_crypt(&state, req, ops);
 431         crypto_aegis128l_final(&state, tag_xor, req->assoclen, cryptlen);
 432 }
 433
 434 static int crypto_aegis128l_encrypt(struct aead_request *req)
 435 {
 436         static const struct aegis128l_ops ops = {
 437                 .skcipher_walk_init = skcipher_walk_aead_encrypt,
 438                 .crypt_chunk = crypto_aegis128l_encrypt_chunk,
 439         };
 440
 441         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 442         union aegis_block tag = {};
 443         unsigned int authsize = crypto_aead_authsize(tfm);
 444         unsigned int cryptlen = req->cryptlen;
 445
 446         crypto_aegis128l_crypt(req, &tag, cryptlen, &ops);
 447
 448         scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
 449                                  authsize, 1);
 450         return 0;
 451 }
 452
 453 static int crypto_aegis128l_decrypt(struct aead_request *req)
 454 {
 455         static const struct aegis128l_ops ops = {
 456                 .skcipher_walk_init = skcipher_walk_aead_decrypt,
 457                 .crypt_chunk = crypto_aegis128l_decrypt_chunk,
 458         };
 459         static const u8 zeros[AEGIS128L_MAX_AUTH_SIZE] = {};
 460
 461         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 462         union aegis_block tag;
 463         unsigned int authsize = crypto_aead_authsize(tfm);
 464         unsigned int cryptlen = req->cryptlen - authsize;
 465
 466         scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
 467                                  authsize, 0);
 468
 469         crypto_aegis128l_crypt(req, &tag, cryptlen, &ops);
 470
 471         return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0;
 472 }
 473
 474 static int crypto_aegis128l_init_tfm(struct crypto_aead *tfm)
 475 {
 476         return 0;
 477 }
 478
 479 static void crypto_aegis128l_exit_tfm(struct crypto_aead *tfm)
 480 {
 481 }
 482
 483 static struct aead_alg crypto_aegis128l_alg = {
 484         .setkey = crypto_aegis128l_setkey,
 485         .setauthsize = crypto_aegis128l_setauthsize,
 486         .encrypt = crypto_aegis128l_encrypt,
 487         .decrypt = crypto_aegis128l_decrypt,
 488         .init = crypto_aegis128l_init_tfm,
 489         .exit = crypto_aegis128l_exit_tfm,
 490
 491         .ivsize = AEGIS128L_NONCE_SIZE,
 492         .maxauthsize = AEGIS128L_MAX_AUTH_SIZE,
 493         .chunksize = AEGIS128L_CHUNK_SIZE,
 494
 495         .base = {
 496                 .cra_blocksize = 1,
 497                 .cra_ctxsize = sizeof(struct aegis_ctx),
 498                 .cra_alignmask = 0,
 499
 500                 .cra_priority = 100,
 501
 502                 .cra_name = "aegis128l",
 503                 .cra_driver_name = "aegis128l-generic",
 504
 505                 .cra_module = THIS_MODULE,
 506         }
 507 };
 508
 509 static int __init crypto_aegis128l_module_init(void)
 510 {
 511         return crypto_register_aead(&crypto_aegis128l_alg);
 512 }
 513
 514 static void __exit crypto_aegis128l_module_exit(void)
 515 {
 516         crypto_unregister_aead(&crypto_aegis128l_alg);
 517 }
 518
 519 module_init(crypto_aegis128l_module_init);
 520 module_exit(crypto_aegis128l_module_exit);
 521
 522 MODULE_LICENSE("GPL");
 523 MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
 524 MODULE_DESCRIPTION("AEGIS-128L AEAD algorithm");
 525 MODULE_ALIAS_CRYPTO("aegis128l");
 526 MODULE_ALIAS_CRYPTO("aegis128l-generic");