linux/crypto/aegis128-core.c
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   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/simd.h>
  12#include <crypto/internal/skcipher.h>
  13#include <crypto/scatterwalk.h>
  14#include <linux/err.h>
  15#include <linux/init.h>
  16#include <linux/jump_label.h>
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/scatterlist.h>
  20
  21#include <asm/simd.h>
  22
  23#include "aegis.h"
  24
  25#define AEGIS128_NONCE_SIZE 16
  26#define AEGIS128_STATE_BLOCKS 5
  27#define AEGIS128_KEY_SIZE 16
  28#define AEGIS128_MIN_AUTH_SIZE 8
  29#define AEGIS128_MAX_AUTH_SIZE 16
  30
  31struct aegis_state {
  32        union aegis_block blocks[AEGIS128_STATE_BLOCKS];
  33};
  34
  35struct aegis_ctx {
  36        union aegis_block key;
  37};
  38
  39static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_simd);
  40
  41static const union aegis_block crypto_aegis_const[2] = {
  42        { .words64 = {
  43                cpu_to_le64(U64_C(0x0d08050302010100)),
  44                cpu_to_le64(U64_C(0x6279e99059372215)),
  45        } },
  46        { .words64 = {
  47                cpu_to_le64(U64_C(0xf12fc26d55183ddb)),
  48                cpu_to_le64(U64_C(0xdd28b57342311120)),
  49        } },
  50};
  51
  52static bool aegis128_do_simd(void)
  53{
  54#ifdef CONFIG_CRYPTO_AEGIS128_SIMD
  55        if (static_branch_likely(&have_simd))
  56                return crypto_simd_usable();
  57#endif
  58        return false;
  59}
  60
  61static void crypto_aegis128_update(struct aegis_state *state)
  62{
  63        union aegis_block tmp;
  64        unsigned int i;
  65
  66        tmp = state->blocks[AEGIS128_STATE_BLOCKS - 1];
  67        for (i = AEGIS128_STATE_BLOCKS - 1; i > 0; i--)
  68                crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1],
  69                                    &state->blocks[i]);
  70        crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]);
  71}
  72
  73static void crypto_aegis128_update_a(struct aegis_state *state,
  74                                     const union aegis_block *msg,
  75                                     bool do_simd)
  76{
  77        if (IS_ENABLED(CONFIG_CRYPTO_AEGIS128_SIMD) && do_simd) {
  78                crypto_aegis128_update_simd(state, msg);
  79                return;
  80        }
  81
  82        crypto_aegis128_update(state);
  83        crypto_aegis_block_xor(&state->blocks[0], msg);
  84}
  85
  86static void crypto_aegis128_update_u(struct aegis_state *state, const void *msg,
  87                                     bool do_simd)
  88{
  89        if (IS_ENABLED(CONFIG_CRYPTO_AEGIS128_SIMD) && do_simd) {
  90                crypto_aegis128_update_simd(state, msg);
  91                return;
  92        }
  93
  94        crypto_aegis128_update(state);
  95        crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE);
  96}
  97
  98static void crypto_aegis128_init(struct aegis_state *state,
  99                                 const union aegis_block *key,
 100                                 const u8 *iv)
 101{
 102        union aegis_block key_iv;
 103        unsigned int i;
 104
 105        key_iv = *key;
 106        crypto_xor(key_iv.bytes, iv, AEGIS_BLOCK_SIZE);
 107
 108        state->blocks[0] = key_iv;
 109        state->blocks[1] = crypto_aegis_const[1];
 110        state->blocks[2] = crypto_aegis_const[0];
 111        state->blocks[3] = *key;
 112        state->blocks[4] = *key;
 113
 114        crypto_aegis_block_xor(&state->blocks[3], &crypto_aegis_const[0]);
 115        crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[1]);
 116
 117        for (i = 0; i < 5; i++) {
 118                crypto_aegis128_update_a(state, key, false);
 119                crypto_aegis128_update_a(state, &key_iv, false);
 120        }
 121}
 122
 123static void crypto_aegis128_ad(struct aegis_state *state,
 124                               const u8 *src, unsigned int size,
 125                               bool do_simd)
 126{
 127        if (AEGIS_ALIGNED(src)) {
 128                const union aegis_block *src_blk =
 129                                (const union aegis_block *)src;
 130
 131                while (size >= AEGIS_BLOCK_SIZE) {
 132                        crypto_aegis128_update_a(state, src_blk, do_simd);
 133
 134                        size -= AEGIS_BLOCK_SIZE;
 135                        src_blk++;
 136                }
 137        } else {
 138                while (size >= AEGIS_BLOCK_SIZE) {
 139                        crypto_aegis128_update_u(state, src, do_simd);
 140
 141                        size -= AEGIS_BLOCK_SIZE;
 142                        src += AEGIS_BLOCK_SIZE;
 143                }
 144        }
 145}
 146
 147static void crypto_aegis128_wipe_chunk(struct aegis_state *state, u8 *dst,
 148                                       const u8 *src, unsigned int size)
 149{
 150        memzero_explicit(dst, size);
 151}
 152
 153static void crypto_aegis128_encrypt_chunk(struct aegis_state *state, u8 *dst,
 154                                          const u8 *src, unsigned int size)
 155{
 156        union aegis_block tmp;
 157
 158        if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 159                while (size >= AEGIS_BLOCK_SIZE) {
 160                        union aegis_block *dst_blk =
 161                                        (union aegis_block *)dst;
 162                        const union aegis_block *src_blk =
 163                                        (const union aegis_block *)src;
 164
 165                        tmp = state->blocks[2];
 166                        crypto_aegis_block_and(&tmp, &state->blocks[3]);
 167                        crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 168                        crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 169                        crypto_aegis_block_xor(&tmp, src_blk);
 170
 171                        crypto_aegis128_update_a(state, src_blk, false);
 172
 173                        *dst_blk = tmp;
 174
 175                        size -= AEGIS_BLOCK_SIZE;
 176                        src += AEGIS_BLOCK_SIZE;
 177                        dst += AEGIS_BLOCK_SIZE;
 178                }
 179        } else {
 180                while (size >= AEGIS_BLOCK_SIZE) {
 181                        tmp = state->blocks[2];
 182                        crypto_aegis_block_and(&tmp, &state->blocks[3]);
 183                        crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 184                        crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 185                        crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
 186
 187                        crypto_aegis128_update_u(state, src, false);
 188
 189                        memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
 190
 191                        size -= AEGIS_BLOCK_SIZE;
 192                        src += AEGIS_BLOCK_SIZE;
 193                        dst += AEGIS_BLOCK_SIZE;
 194                }
 195        }
 196
 197        if (size > 0) {
 198                union aegis_block msg = {};
 199                memcpy(msg.bytes, src, size);
 200
 201                tmp = state->blocks[2];
 202                crypto_aegis_block_and(&tmp, &state->blocks[3]);
 203                crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 204                crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 205
 206                crypto_aegis128_update_a(state, &msg, false);
 207
 208                crypto_aegis_block_xor(&msg, &tmp);
 209
 210                memcpy(dst, msg.bytes, size);
 211        }
 212}
 213
 214static void crypto_aegis128_decrypt_chunk(struct aegis_state *state, u8 *dst,
 215                                          const u8 *src, unsigned int size)
 216{
 217        union aegis_block tmp;
 218
 219        if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) {
 220                while (size >= AEGIS_BLOCK_SIZE) {
 221                        union aegis_block *dst_blk =
 222                                        (union aegis_block *)dst;
 223                        const union aegis_block *src_blk =
 224                                        (const union aegis_block *)src;
 225
 226                        tmp = state->blocks[2];
 227                        crypto_aegis_block_and(&tmp, &state->blocks[3]);
 228                        crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 229                        crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 230                        crypto_aegis_block_xor(&tmp, src_blk);
 231
 232                        crypto_aegis128_update_a(state, &tmp, false);
 233
 234                        *dst_blk = tmp;
 235
 236                        size -= AEGIS_BLOCK_SIZE;
 237                        src += AEGIS_BLOCK_SIZE;
 238                        dst += AEGIS_BLOCK_SIZE;
 239                }
 240        } else {
 241                while (size >= AEGIS_BLOCK_SIZE) {
 242                        tmp = state->blocks[2];
 243                        crypto_aegis_block_and(&tmp, &state->blocks[3]);
 244                        crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 245                        crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 246                        crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE);
 247
 248                        crypto_aegis128_update_a(state, &tmp, false);
 249
 250                        memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE);
 251
 252                        size -= AEGIS_BLOCK_SIZE;
 253                        src += AEGIS_BLOCK_SIZE;
 254                        dst += AEGIS_BLOCK_SIZE;
 255                }
 256        }
 257
 258        if (size > 0) {
 259                union aegis_block msg = {};
 260                memcpy(msg.bytes, src, size);
 261
 262                tmp = state->blocks[2];
 263                crypto_aegis_block_and(&tmp, &state->blocks[3]);
 264                crypto_aegis_block_xor(&tmp, &state->blocks[4]);
 265                crypto_aegis_block_xor(&tmp, &state->blocks[1]);
 266                crypto_aegis_block_xor(&msg, &tmp);
 267
 268                memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size);
 269
 270                crypto_aegis128_update_a(state, &msg, false);
 271
 272                memcpy(dst, msg.bytes, size);
 273        }
 274}
 275
 276static void crypto_aegis128_process_ad(struct aegis_state *state,
 277                                       struct scatterlist *sg_src,
 278                                       unsigned int assoclen,
 279                                       bool do_simd)
 280{
 281        struct scatter_walk walk;
 282        union aegis_block buf;
 283        unsigned int pos = 0;
 284
 285        scatterwalk_start(&walk, sg_src);
 286        while (assoclen != 0) {
 287                unsigned int size = scatterwalk_clamp(&walk, assoclen);
 288                unsigned int left = size;
 289                void *mapped = scatterwalk_map(&walk);
 290                const u8 *src = (const u8 *)mapped;
 291
 292                if (pos + size >= AEGIS_BLOCK_SIZE) {
 293                        if (pos > 0) {
 294                                unsigned int fill = AEGIS_BLOCK_SIZE - pos;
 295                                memcpy(buf.bytes + pos, src, fill);
 296                                crypto_aegis128_update_a(state, &buf, do_simd);
 297                                pos = 0;
 298                                left -= fill;
 299                                src += fill;
 300                        }
 301
 302                        crypto_aegis128_ad(state, src, left, do_simd);
 303                        src += left & ~(AEGIS_BLOCK_SIZE - 1);
 304                        left &= AEGIS_BLOCK_SIZE - 1;
 305                }
 306
 307                memcpy(buf.bytes + pos, src, left);
 308
 309                pos += left;
 310                assoclen -= size;
 311                scatterwalk_unmap(mapped);
 312                scatterwalk_advance(&walk, size);
 313                scatterwalk_done(&walk, 0, assoclen);
 314        }
 315
 316        if (pos > 0) {
 317                memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos);
 318                crypto_aegis128_update_a(state, &buf, do_simd);
 319        }
 320}
 321
 322static __always_inline
 323int crypto_aegis128_process_crypt(struct aegis_state *state,
 324                                  struct skcipher_walk *walk,
 325                                  void (*crypt)(struct aegis_state *state,
 326                                                u8 *dst, const u8 *src,
 327                                                unsigned int size))
 328{
 329        int err = 0;
 330
 331        while (walk->nbytes) {
 332                unsigned int nbytes = walk->nbytes;
 333
 334                if (nbytes < walk->total)
 335                        nbytes = round_down(nbytes, walk->stride);
 336
 337                crypt(state, walk->dst.virt.addr, walk->src.virt.addr, nbytes);
 338
 339                err = skcipher_walk_done(walk, walk->nbytes - nbytes);
 340        }
 341        return err;
 342}
 343
 344static void crypto_aegis128_final(struct aegis_state *state,
 345                                  union aegis_block *tag_xor,
 346                                  u64 assoclen, u64 cryptlen)
 347{
 348        u64 assocbits = assoclen * 8;
 349        u64 cryptbits = cryptlen * 8;
 350
 351        union aegis_block tmp;
 352        unsigned int i;
 353
 354        tmp.words64[0] = cpu_to_le64(assocbits);
 355        tmp.words64[1] = cpu_to_le64(cryptbits);
 356
 357        crypto_aegis_block_xor(&tmp, &state->blocks[3]);
 358
 359        for (i = 0; i < 7; i++)
 360                crypto_aegis128_update_a(state, &tmp, false);
 361
 362        for (i = 0; i < AEGIS128_STATE_BLOCKS; i++)
 363                crypto_aegis_block_xor(tag_xor, &state->blocks[i]);
 364}
 365
 366static int crypto_aegis128_setkey(struct crypto_aead *aead, const u8 *key,
 367                                  unsigned int keylen)
 368{
 369        struct aegis_ctx *ctx = crypto_aead_ctx(aead);
 370
 371        if (keylen != AEGIS128_KEY_SIZE)
 372                return -EINVAL;
 373
 374        memcpy(ctx->key.bytes, key, AEGIS128_KEY_SIZE);
 375        return 0;
 376}
 377
 378static int crypto_aegis128_setauthsize(struct crypto_aead *tfm,
 379                                       unsigned int authsize)
 380{
 381        if (authsize > AEGIS128_MAX_AUTH_SIZE)
 382                return -EINVAL;
 383        if (authsize < AEGIS128_MIN_AUTH_SIZE)
 384                return -EINVAL;
 385        return 0;
 386}
 387
 388static int crypto_aegis128_encrypt_generic(struct aead_request *req)
 389{
 390        struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 391        union aegis_block tag = {};
 392        unsigned int authsize = crypto_aead_authsize(tfm);
 393        struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 394        unsigned int cryptlen = req->cryptlen;
 395        struct skcipher_walk walk;
 396        struct aegis_state state;
 397
 398        skcipher_walk_aead_encrypt(&walk, req, false);
 399        crypto_aegis128_init(&state, &ctx->key, req->iv);
 400        crypto_aegis128_process_ad(&state, req->src, req->assoclen, false);
 401        crypto_aegis128_process_crypt(&state, &walk,
 402                                      crypto_aegis128_encrypt_chunk);
 403        crypto_aegis128_final(&state, &tag, req->assoclen, cryptlen);
 404
 405        scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
 406                                 authsize, 1);
 407        return 0;
 408}
 409
 410static int crypto_aegis128_decrypt_generic(struct aead_request *req)
 411{
 412        static const u8 zeros[AEGIS128_MAX_AUTH_SIZE] = {};
 413        struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 414        union aegis_block tag;
 415        unsigned int authsize = crypto_aead_authsize(tfm);
 416        unsigned int cryptlen = req->cryptlen - authsize;
 417        struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 418        struct skcipher_walk walk;
 419        struct aegis_state state;
 420
 421        scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
 422                                 authsize, 0);
 423
 424        skcipher_walk_aead_decrypt(&walk, req, false);
 425        crypto_aegis128_init(&state, &ctx->key, req->iv);
 426        crypto_aegis128_process_ad(&state, req->src, req->assoclen, false);
 427        crypto_aegis128_process_crypt(&state, &walk,
 428                                      crypto_aegis128_decrypt_chunk);
 429        crypto_aegis128_final(&state, &tag, req->assoclen, cryptlen);
 430
 431        if (unlikely(crypto_memneq(tag.bytes, zeros, authsize))) {
 432                /*
 433                 * From Chapter 4. 'Security Analysis' of the AEGIS spec [0]
 434                 *
 435                 * "3. If verification fails, the decrypted plaintext and the
 436                 *     wrong authentication tag should not be given as output."
 437                 *
 438                 * [0] https://competitions.cr.yp.to/round3/aegisv11.pdf
 439                 */
 440                skcipher_walk_aead_decrypt(&walk, req, false);
 441                crypto_aegis128_process_crypt(NULL, &walk,
 442                                              crypto_aegis128_wipe_chunk);
 443                memzero_explicit(&tag, sizeof(tag));
 444                return -EBADMSG;
 445        }
 446        return 0;
 447}
 448
 449static int crypto_aegis128_encrypt_simd(struct aead_request *req)
 450{
 451        struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 452        union aegis_block tag = {};
 453        unsigned int authsize = crypto_aead_authsize(tfm);
 454        struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 455        unsigned int cryptlen = req->cryptlen;
 456        struct skcipher_walk walk;
 457        struct aegis_state state;
 458
 459        if (!aegis128_do_simd())
 460                return crypto_aegis128_encrypt_generic(req);
 461
 462        skcipher_walk_aead_encrypt(&walk, req, false);
 463        crypto_aegis128_init_simd(&state, &ctx->key, req->iv);
 464        crypto_aegis128_process_ad(&state, req->src, req->assoclen, true);
 465        crypto_aegis128_process_crypt(&state, &walk,
 466                                      crypto_aegis128_encrypt_chunk_simd);
 467        crypto_aegis128_final_simd(&state, &tag, req->assoclen, cryptlen, 0);
 468
 469        scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen,
 470                                 authsize, 1);
 471        return 0;
 472}
 473
 474static int crypto_aegis128_decrypt_simd(struct aead_request *req)
 475{
 476        struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 477        union aegis_block tag;
 478        unsigned int authsize = crypto_aead_authsize(tfm);
 479        unsigned int cryptlen = req->cryptlen - authsize;
 480        struct aegis_ctx *ctx = crypto_aead_ctx(tfm);
 481        struct skcipher_walk walk;
 482        struct aegis_state state;
 483
 484        if (!aegis128_do_simd())
 485                return crypto_aegis128_decrypt_generic(req);
 486
 487        scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen,
 488                                 authsize, 0);
 489
 490        skcipher_walk_aead_decrypt(&walk, req, false);
 491        crypto_aegis128_init_simd(&state, &ctx->key, req->iv);
 492        crypto_aegis128_process_ad(&state, req->src, req->assoclen, true);
 493        crypto_aegis128_process_crypt(&state, &walk,
 494                                      crypto_aegis128_decrypt_chunk_simd);
 495
 496        if (unlikely(crypto_aegis128_final_simd(&state, &tag, req->assoclen,
 497                                                cryptlen, authsize))) {
 498                skcipher_walk_aead_decrypt(&walk, req, false);
 499                crypto_aegis128_process_crypt(NULL, &walk,
 500                                              crypto_aegis128_wipe_chunk);
 501                return -EBADMSG;
 502        }
 503        return 0;
 504}
 505
 506static struct aead_alg crypto_aegis128_alg_generic = {
 507        .setkey                 = crypto_aegis128_setkey,
 508        .setauthsize            = crypto_aegis128_setauthsize,
 509        .encrypt                = crypto_aegis128_encrypt_generic,
 510        .decrypt                = crypto_aegis128_decrypt_generic,
 511
 512        .ivsize                 = AEGIS128_NONCE_SIZE,
 513        .maxauthsize            = AEGIS128_MAX_AUTH_SIZE,
 514        .chunksize              = AEGIS_BLOCK_SIZE,
 515
 516        .base.cra_blocksize     = 1,
 517        .base.cra_ctxsize       = sizeof(struct aegis_ctx),
 518        .base.cra_alignmask     = 0,
 519        .base.cra_priority      = 100,
 520        .base.cra_name          = "aegis128",
 521        .base.cra_driver_name   = "aegis128-generic",
 522        .base.cra_module        = THIS_MODULE,
 523};
 524
 525static struct aead_alg crypto_aegis128_alg_simd = {
 526        .setkey                 = crypto_aegis128_setkey,
 527        .setauthsize            = crypto_aegis128_setauthsize,
 528        .encrypt                = crypto_aegis128_encrypt_simd,
 529        .decrypt                = crypto_aegis128_decrypt_simd,
 530
 531        .ivsize                 = AEGIS128_NONCE_SIZE,
 532        .maxauthsize            = AEGIS128_MAX_AUTH_SIZE,
 533        .chunksize              = AEGIS_BLOCK_SIZE,
 534
 535        .base.cra_blocksize     = 1,
 536        .base.cra_ctxsize       = sizeof(struct aegis_ctx),
 537        .base.cra_alignmask     = 0,
 538        .base.cra_priority      = 200,
 539        .base.cra_name          = "aegis128",
 540        .base.cra_driver_name   = "aegis128-simd",
 541        .base.cra_module        = THIS_MODULE,
 542};
 543
 544static int __init crypto_aegis128_module_init(void)
 545{
 546        int ret;
 547
 548        ret = crypto_register_aead(&crypto_aegis128_alg_generic);
 549        if (ret)
 550                return ret;
 551
 552        if (IS_ENABLED(CONFIG_CRYPTO_AEGIS128_SIMD) &&
 553            crypto_aegis128_have_simd()) {
 554                ret = crypto_register_aead(&crypto_aegis128_alg_simd);
 555                if (ret) {
 556                        crypto_unregister_aead(&crypto_aegis128_alg_generic);
 557                        return ret;
 558                }
 559                static_branch_enable(&have_simd);
 560        }
 561        return 0;
 562}
 563
 564static void __exit crypto_aegis128_module_exit(void)
 565{
 566        if (IS_ENABLED(CONFIG_CRYPTO_AEGIS128_SIMD) &&
 567            crypto_aegis128_have_simd())
 568                crypto_unregister_aead(&crypto_aegis128_alg_simd);
 569
 570        crypto_unregister_aead(&crypto_aegis128_alg_generic);
 571}
 572
 573subsys_initcall(crypto_aegis128_module_init);
 574module_exit(crypto_aegis128_module_exit);
 575
 576MODULE_LICENSE("GPL");
 577MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>");
 578MODULE_DESCRIPTION("AEGIS-128 AEAD algorithm");
 579MODULE_ALIAS_CRYPTO("aegis128");
 580MODULE_ALIAS_CRYPTO("aegis128-generic");
 581MODULE_ALIAS_CRYPTO("aegis128-simd");
 582