arch/arm64/crypto/ghash-ce-glue.c

   1 /*
   2  * Accelerated GHASH implementation with ARMv8 PMULL instructions.
   3  *
   4  * Copyright (C) 2014 - 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  */
  10
  11 #include <asm/neon.h>
  12 #include <asm/simd.h>
  13 #include <asm/unaligned.h>
  14 #include <crypto/aes.h>
  15 #include <crypto/algapi.h>
  16 #include <crypto/b128ops.h>
  17 #include <crypto/gf128mul.h>
  18 #include <crypto/internal/aead.h>
  19 #include <crypto/internal/hash.h>
  20 #include <crypto/internal/skcipher.h>
  21 #include <crypto/scatterwalk.h>
  22 #include <linux/cpufeature.h>
  23 #include <linux/crypto.h>
  24 #include <linux/module.h>
  25
  26 MODULE_DESCRIPTION("GHASH and AES-GCM using ARMv8 Crypto Extensions");
  27 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  28 MODULE_LICENSE("GPL v2");
  29 MODULE_ALIAS_CRYPTO("ghash");
  30
  31 #define GHASH_BLOCK_SIZE        16
  32 #define GHASH_DIGEST_SIZE       16
  33 #define GCM_IV_SIZE             12
  34
  35 struct ghash_key {
  36         u64 a;
  37         u64 b;
  38         be128 k;
  39 };
  40
  41 struct ghash_desc_ctx {
  42         u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
  43         u8 buf[GHASH_BLOCK_SIZE];
  44         u32 count;
  45 };
  46
  47 struct gcm_aes_ctx {
  48         struct crypto_aes_ctx   aes_key;
  49         struct ghash_key        ghash_key;
  50 };
  51
  52 asmlinkage void pmull_ghash_update_p64(int blocks, u64 dg[], const char *src,
  53                                        struct ghash_key const *k,
  54                                        const char *head);
  55
  56 asmlinkage void pmull_ghash_update_p8(int blocks, u64 dg[], const char *src,
  57                                       struct ghash_key const *k,
  58                                       const char *head);
  59
  60 static void (*pmull_ghash_update)(int blocks, u64 dg[], const char *src,
  61                                   struct ghash_key const *k,
  62                                   const char *head);
  63
  64 asmlinkage void pmull_gcm_encrypt(int blocks, u64 dg[], u8 dst[],
  65                                   const u8 src[], struct ghash_key const *k,
  66                                   u8 ctr[], int rounds, u8 ks[]);
  67
  68 asmlinkage void pmull_gcm_decrypt(int blocks, u64 dg[], u8 dst[],
  69                                   const u8 src[], struct ghash_key const *k,
  70                                   u8 ctr[], int rounds);
  71
  72 asmlinkage void pmull_gcm_encrypt_block(u8 dst[], u8 const src[],
  73                                         u32 const rk[], int rounds);
  74
  75 asmlinkage void __aes_arm64_encrypt(u32 *rk, u8 *out, const u8 *in, int rounds);
  76
  77 static int ghash_init(struct shash_desc *desc)
  78 {
  79         struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
  80
  81         *ctx = (struct ghash_desc_ctx){};
  82         return 0;
  83 }
  84
  85 static void ghash_do_update(int blocks, u64 dg[], const char *src,
  86                             struct ghash_key *key, const char *head)
  87 {
  88         if (likely(may_use_simd())) {
  89                 kernel_neon_begin();
  90                 pmull_ghash_update(blocks, dg, src, key, head);
  91                 kernel_neon_end();
  92         } else {
  93                 be128 dst = { cpu_to_be64(dg[1]), cpu_to_be64(dg[0]) };
  94
  95                 do {
  96                         const u8 *in = src;
  97
  98                         if (head) {
  99                                 in = head;
 100                                 blocks++;
 101                                 head = NULL;
 102                         } else {
 103                                 src += GHASH_BLOCK_SIZE;
 104                         }
 105
 106                         crypto_xor((u8 *)&dst, in, GHASH_BLOCK_SIZE);
 107                         gf128mul_lle(&dst, &key->k);
 108                 } while (--blocks);
 109
 110                 dg[0] = be64_to_cpu(dst.b);
 111                 dg[1] = be64_to_cpu(dst.a);
 112         }
 113 }
 114
 115 static int ghash_update(struct shash_desc *desc, const u8 *src,
 116                         unsigned int len)
 117 {
 118         struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
 119         unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
 120
 121         ctx->count += len;
 122
 123         if ((partial + len) >= GHASH_BLOCK_SIZE) {
 124                 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
 125                 int blocks;
 126
 127                 if (partial) {
 128                         int p = GHASH_BLOCK_SIZE - partial;
 129
 130                         memcpy(ctx->buf + partial, src, p);
 131                         src += p;
 132                         len -= p;
 133                 }
 134
 135                 blocks = len / GHASH_BLOCK_SIZE;
 136                 len %= GHASH_BLOCK_SIZE;
 137
 138                 ghash_do_update(blocks, ctx->digest, src, key,
 139                                 partial ? ctx->buf : NULL);
 140
 141                 src += blocks * GHASH_BLOCK_SIZE;
 142                 partial = 0;
 143         }
 144         if (len)
 145                 memcpy(ctx->buf + partial, src, len);
 146         return 0;
 147 }
 148
 149 static int ghash_final(struct shash_desc *desc, u8 *dst)
 150 {
 151         struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
 152         unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
 153
 154         if (partial) {
 155                 struct ghash_key *key = crypto_shash_ctx(desc->tfm);
 156
 157                 memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
 158
 159                 ghash_do_update(1, ctx->digest, ctx->buf, key, NULL);
 160         }
 161         put_unaligned_be64(ctx->digest[1], dst);
 162         put_unaligned_be64(ctx->digest[0], dst + 8);
 163
 164         *ctx = (struct ghash_desc_ctx){};
 165         return 0;
 166 }
 167
 168 static int __ghash_setkey(struct ghash_key *key,
 169                           const u8 *inkey, unsigned int keylen)
 170 {
 171         u64 a, b;
 172
 173         /* needed for the fallback */
 174         memcpy(&key->k, inkey, GHASH_BLOCK_SIZE);
 175
 176         /* perform multiplication by 'x' in GF(2^128) */
 177         b = get_unaligned_be64(inkey);
 178         a = get_unaligned_be64(inkey + 8);
 179
 180         key->a = (a << 1) | (b >> 63);
 181         key->b = (b << 1) | (a >> 63);
 182
 183         if (b >> 63)
 184                 key->b ^= 0xc200000000000000UL;
 185
 186         return 0;
 187 }
 188
 189 static int ghash_setkey(struct crypto_shash *tfm,
 190                         const u8 *inkey, unsigned int keylen)
 191 {
 192         struct ghash_key *key = crypto_shash_ctx(tfm);
 193
 194         if (keylen != GHASH_BLOCK_SIZE) {
 195                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 196                 return -EINVAL;
 197         }
 198
 199         return __ghash_setkey(key, inkey, keylen);
 200 }
 201
 202 static struct shash_alg ghash_alg = {
 203         .base.cra_name          = "ghash",
 204         .base.cra_driver_name   = "ghash-ce",
 205         .base.cra_priority      = 200,
 206         .base.cra_flags         = CRYPTO_ALG_TYPE_SHASH,
 207         .base.cra_blocksize     = GHASH_BLOCK_SIZE,
 208         .base.cra_ctxsize       = sizeof(struct ghash_key),
 209         .base.cra_module        = THIS_MODULE,
 210
 211         .digestsize             = GHASH_DIGEST_SIZE,
 212         .init                   = ghash_init,
 213         .update                 = ghash_update,
 214         .final                  = ghash_final,
 215         .setkey                 = ghash_setkey,
 216         .descsize               = sizeof(struct ghash_desc_ctx),
 217 };
 218
 219 static int num_rounds(struct crypto_aes_ctx *ctx)
 220 {
 221         /*
 222          * # of rounds specified by AES:
 223          * 128 bit key          10 rounds
 224          * 192 bit key          12 rounds
 225          * 256 bit key          14 rounds
 226          * => n byte key        => 6 + (n/4) rounds
 227          */
 228         return 6 + ctx->key_length / 4;
 229 }
 230
 231 static int gcm_setkey(struct crypto_aead *tfm, const u8 *inkey,
 232                       unsigned int keylen)
 233 {
 234         struct gcm_aes_ctx *ctx = crypto_aead_ctx(tfm);
 235         u8 key[GHASH_BLOCK_SIZE];
 236         int ret;
 237
 238         ret = crypto_aes_expand_key(&ctx->aes_key, inkey, keylen);
 239         if (ret) {
 240                 tfm->base.crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 241                 return -EINVAL;
 242         }
 243
 244         __aes_arm64_encrypt(ctx->aes_key.key_enc, key, (u8[AES_BLOCK_SIZE]){},
 245                             num_rounds(&ctx->aes_key));
 246
 247         return __ghash_setkey(&ctx->ghash_key, key, sizeof(key));
 248 }
 249
 250 static int gcm_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
 251 {
 252         switch (authsize) {
 253         case 4:
 254         case 8:
 255         case 12 ... 16:
 256                 break;
 257         default:
 258                 return -EINVAL;
 259         }
 260         return 0;
 261 }
 262
 263 static void gcm_update_mac(u64 dg[], const u8 *src, int count, u8 buf[],
 264                            int *buf_count, struct gcm_aes_ctx *ctx)
 265 {
 266         if (*buf_count > 0) {
 267                 int buf_added = min(count, GHASH_BLOCK_SIZE - *buf_count);
 268
 269                 memcpy(&buf[*buf_count], src, buf_added);
 270
 271                 *buf_count += buf_added;
 272                 src += buf_added;
 273                 count -= buf_added;
 274         }
 275
 276         if (count >= GHASH_BLOCK_SIZE || *buf_count == GHASH_BLOCK_SIZE) {
 277                 int blocks = count / GHASH_BLOCK_SIZE;
 278
 279                 ghash_do_update(blocks, dg, src, &ctx->ghash_key,
 280                                 *buf_count ? buf : NULL);
 281
 282                 src += blocks * GHASH_BLOCK_SIZE;
 283                 count %= GHASH_BLOCK_SIZE;
 284                 *buf_count = 0;
 285         }
 286
 287         if (count > 0) {
 288                 memcpy(buf, src, count);
 289                 *buf_count = count;
 290         }
 291 }
 292
 293 static void gcm_calculate_auth_mac(struct aead_request *req, u64 dg[])
 294 {
 295         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 296         struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 297         u8 buf[GHASH_BLOCK_SIZE];
 298         struct scatter_walk walk;
 299         u32 len = req->assoclen;
 300         int buf_count = 0;
 301
 302         scatterwalk_start(&walk, req->src);
 303
 304         do {
 305                 u32 n = scatterwalk_clamp(&walk, len);
 306                 u8 *p;
 307
 308                 if (!n) {
 309                         scatterwalk_start(&walk, sg_next(walk.sg));
 310                         n = scatterwalk_clamp(&walk, len);
 311                 }
 312                 p = scatterwalk_map(&walk);
 313
 314                 gcm_update_mac(dg, p, n, buf, &buf_count, ctx);
 315                 len -= n;
 316
 317                 scatterwalk_unmap(p);
 318                 scatterwalk_advance(&walk, n);
 319                 scatterwalk_done(&walk, 0, len);
 320         } while (len);
 321
 322         if (buf_count) {
 323                 memset(&buf[buf_count], 0, GHASH_BLOCK_SIZE - buf_count);
 324                 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
 325         }
 326 }
 327
 328 static void gcm_final(struct aead_request *req, struct gcm_aes_ctx *ctx,
 329                       u64 dg[], u8 tag[], int cryptlen)
 330 {
 331         u8 mac[AES_BLOCK_SIZE];
 332         u128 lengths;
 333
 334         lengths.a = cpu_to_be64(req->assoclen * 8);
 335         lengths.b = cpu_to_be64(cryptlen * 8);
 336
 337         ghash_do_update(1, dg, (void *)&lengths, &ctx->ghash_key, NULL);
 338
 339         put_unaligned_be64(dg[1], mac);
 340         put_unaligned_be64(dg[0], mac + 8);
 341
 342         crypto_xor(tag, mac, AES_BLOCK_SIZE);
 343 }
 344
 345 static int gcm_encrypt(struct aead_request *req)
 346 {
 347         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 348         struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 349         struct skcipher_walk walk;
 350         u8 iv[AES_BLOCK_SIZE];
 351         u8 ks[AES_BLOCK_SIZE];
 352         u8 tag[AES_BLOCK_SIZE];
 353         u64 dg[2] = {};
 354         int err;
 355
 356         if (req->assoclen)
 357                 gcm_calculate_auth_mac(req, dg);
 358
 359         memcpy(iv, req->iv, GCM_IV_SIZE);
 360         put_unaligned_be32(1, iv + GCM_IV_SIZE);
 361
 362         if (likely(may_use_simd())) {
 363                 kernel_neon_begin();
 364
 365                 pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
 366                                         num_rounds(&ctx->aes_key));
 367                 put_unaligned_be32(2, iv + GCM_IV_SIZE);
 368                 pmull_gcm_encrypt_block(ks, iv, NULL,
 369                                         num_rounds(&ctx->aes_key));
 370                 put_unaligned_be32(3, iv + GCM_IV_SIZE);
 371
 372                 err = skcipher_walk_aead_encrypt(&walk, req, true);
 373
 374                 while (walk.nbytes >= AES_BLOCK_SIZE) {
 375                         int blocks = walk.nbytes / AES_BLOCK_SIZE;
 376
 377                         pmull_gcm_encrypt(blocks, dg, walk.dst.virt.addr,
 378                                           walk.src.virt.addr, &ctx->ghash_key,
 379                                           iv, num_rounds(&ctx->aes_key), ks);
 380
 381                         err = skcipher_walk_done(&walk,
 382                                                  walk.nbytes % AES_BLOCK_SIZE);
 383                 }
 384                 kernel_neon_end();
 385         } else {
 386                 __aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
 387                                     num_rounds(&ctx->aes_key));
 388                 put_unaligned_be32(2, iv + GCM_IV_SIZE);
 389
 390                 err = skcipher_walk_aead_encrypt(&walk, req, true);
 391
 392                 while (walk.nbytes >= AES_BLOCK_SIZE) {
 393                         int blocks = walk.nbytes / AES_BLOCK_SIZE;
 394                         u8 *dst = walk.dst.virt.addr;
 395                         u8 *src = walk.src.virt.addr;
 396
 397                         do {
 398                                 __aes_arm64_encrypt(ctx->aes_key.key_enc,
 399                                                     ks, iv,
 400                                                     num_rounds(&ctx->aes_key));
 401                                 crypto_xor_cpy(dst, src, ks, AES_BLOCK_SIZE);
 402                                 crypto_inc(iv, AES_BLOCK_SIZE);
 403
 404                                 dst += AES_BLOCK_SIZE;
 405                                 src += AES_BLOCK_SIZE;
 406                         } while (--blocks > 0);
 407
 408                         ghash_do_update(walk.nbytes / AES_BLOCK_SIZE, dg,
 409                                         walk.dst.virt.addr, &ctx->ghash_key,
 410                                         NULL);
 411
 412                         err = skcipher_walk_done(&walk,
 413                                                  walk.nbytes % AES_BLOCK_SIZE);
 414                 }
 415                 if (walk.nbytes)
 416                         __aes_arm64_encrypt(ctx->aes_key.key_enc, ks, iv,
 417                                             num_rounds(&ctx->aes_key));
 418         }
 419
 420         /* handle the tail */
 421         if (walk.nbytes) {
 422                 u8 buf[GHASH_BLOCK_SIZE];
 423
 424                 crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, ks,
 425                                walk.nbytes);
 426
 427                 memcpy(buf, walk.dst.virt.addr, walk.nbytes);
 428                 memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
 429                 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
 430
 431                 err = skcipher_walk_done(&walk, 0);
 432         }
 433
 434         if (err)
 435                 return err;
 436
 437         gcm_final(req, ctx, dg, tag, req->cryptlen);
 438
 439         /* copy authtag to end of dst */
 440         scatterwalk_map_and_copy(tag, req->dst, req->assoclen + req->cryptlen,
 441                                  crypto_aead_authsize(aead), 1);
 442
 443         return 0;
 444 }
 445
 446 static int gcm_decrypt(struct aead_request *req)
 447 {
 448         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 449         struct gcm_aes_ctx *ctx = crypto_aead_ctx(aead);
 450         unsigned int authsize = crypto_aead_authsize(aead);
 451         struct skcipher_walk walk;
 452         u8 iv[AES_BLOCK_SIZE];
 453         u8 tag[AES_BLOCK_SIZE];
 454         u8 buf[GHASH_BLOCK_SIZE];
 455         u64 dg[2] = {};
 456         int err;
 457
 458         if (req->assoclen)
 459                 gcm_calculate_auth_mac(req, dg);
 460
 461         memcpy(iv, req->iv, GCM_IV_SIZE);
 462         put_unaligned_be32(1, iv + GCM_IV_SIZE);
 463
 464         if (likely(may_use_simd())) {
 465                 kernel_neon_begin();
 466
 467                 pmull_gcm_encrypt_block(tag, iv, ctx->aes_key.key_enc,
 468                                         num_rounds(&ctx->aes_key));
 469                 put_unaligned_be32(2, iv + GCM_IV_SIZE);
 470
 471                 err = skcipher_walk_aead_decrypt(&walk, req, true);
 472
 473                 while (walk.nbytes >= AES_BLOCK_SIZE) {
 474                         int blocks = walk.nbytes / AES_BLOCK_SIZE;
 475
 476                         pmull_gcm_decrypt(blocks, dg, walk.dst.virt.addr,
 477                                           walk.src.virt.addr, &ctx->ghash_key,
 478                                           iv, num_rounds(&ctx->aes_key));
 479
 480                         err = skcipher_walk_done(&walk,
 481                                                  walk.nbytes % AES_BLOCK_SIZE);
 482                 }
 483                 if (walk.nbytes)
 484                         pmull_gcm_encrypt_block(iv, iv, NULL,
 485                                                 num_rounds(&ctx->aes_key));
 486
 487                 kernel_neon_end();
 488         } else {
 489                 __aes_arm64_encrypt(ctx->aes_key.key_enc, tag, iv,
 490                                     num_rounds(&ctx->aes_key));
 491                 put_unaligned_be32(2, iv + GCM_IV_SIZE);
 492
 493                 err = skcipher_walk_aead_decrypt(&walk, req, true);
 494
 495                 while (walk.nbytes >= AES_BLOCK_SIZE) {
 496                         int blocks = walk.nbytes / AES_BLOCK_SIZE;
 497                         u8 *dst = walk.dst.virt.addr;
 498                         u8 *src = walk.src.virt.addr;
 499
 500                         ghash_do_update(blocks, dg, walk.src.virt.addr,
 501                                         &ctx->ghash_key, NULL);
 502
 503                         do {
 504                                 __aes_arm64_encrypt(ctx->aes_key.key_enc,
 505                                                     buf, iv,
 506                                                     num_rounds(&ctx->aes_key));
 507                                 crypto_xor_cpy(dst, src, buf, AES_BLOCK_SIZE);
 508                                 crypto_inc(iv, AES_BLOCK_SIZE);
 509
 510                                 dst += AES_BLOCK_SIZE;
 511                                 src += AES_BLOCK_SIZE;
 512                         } while (--blocks > 0);
 513
 514                         err = skcipher_walk_done(&walk,
 515                                                  walk.nbytes % AES_BLOCK_SIZE);
 516                 }
 517                 if (walk.nbytes)
 518                         __aes_arm64_encrypt(ctx->aes_key.key_enc, iv, iv,
 519                                             num_rounds(&ctx->aes_key));
 520         }
 521
 522         /* handle the tail */
 523         if (walk.nbytes) {
 524                 memcpy(buf, walk.src.virt.addr, walk.nbytes);
 525                 memset(buf + walk.nbytes, 0, GHASH_BLOCK_SIZE - walk.nbytes);
 526                 ghash_do_update(1, dg, buf, &ctx->ghash_key, NULL);
 527
 528                 crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, iv,
 529                                walk.nbytes);
 530
 531                 err = skcipher_walk_done(&walk, 0);
 532         }
 533
 534         if (err)
 535                 return err;
 536
 537         gcm_final(req, ctx, dg, tag, req->cryptlen - authsize);
 538
 539         /* compare calculated auth tag with the stored one */
 540         scatterwalk_map_and_copy(buf, req->src,
 541                                  req->assoclen + req->cryptlen - authsize,
 542                                  authsize, 0);
 543
 544         if (crypto_memneq(tag, buf, authsize))
 545                 return -EBADMSG;
 546         return 0;
 547 }
 548
 549 static struct aead_alg gcm_aes_alg = {
 550         .ivsize                 = GCM_IV_SIZE,
 551         .chunksize              = AES_BLOCK_SIZE,
 552         .maxauthsize            = AES_BLOCK_SIZE,
 553         .setkey                 = gcm_setkey,
 554         .setauthsize            = gcm_setauthsize,
 555         .encrypt                = gcm_encrypt,
 556         .decrypt                = gcm_decrypt,
 557
 558         .base.cra_name          = "gcm(aes)",
 559         .base.cra_driver_name   = "gcm-aes-ce",
 560         .base.cra_priority      = 300,
 561         .base.cra_blocksize     = 1,
 562         .base.cra_ctxsize       = sizeof(struct gcm_aes_ctx),
 563         .base.cra_module        = THIS_MODULE,
 564 };
 565
 566 static int __init ghash_ce_mod_init(void)
 567 {
 568         int ret;
 569
 570         if (!(elf_hwcap & HWCAP_ASIMD))
 571                 return -ENODEV;
 572
 573         if (elf_hwcap & HWCAP_PMULL)
 574                 pmull_ghash_update = pmull_ghash_update_p64;
 575
 576         else
 577                 pmull_ghash_update = pmull_ghash_update_p8;
 578
 579         ret = crypto_register_shash(&ghash_alg);
 580         if (ret)
 581                 return ret;
 582
 583         if (elf_hwcap & HWCAP_PMULL) {
 584                 ret = crypto_register_aead(&gcm_aes_alg);
 585                 if (ret)
 586                         crypto_unregister_shash(&ghash_alg);
 587         }
 588         return ret;
 589 }
 590
 591 static void __exit ghash_ce_mod_exit(void)
 592 {
 593         crypto_unregister_shash(&ghash_alg);
 594         crypto_unregister_aead(&gcm_aes_alg);
 595 }
 596
 597 static const struct cpu_feature ghash_cpu_feature[] = {
 598         { cpu_feature(PMULL) }, { }
 599 };
 600 MODULE_DEVICE_TABLE(cpu, ghash_cpu_feature);
 601
 602 module_init(ghash_ce_mod_init);
 603 module_exit(ghash_ce_mod_exit);