arch/arm/crypto/aes-neonbs-glue.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Bit sliced AES using NEON instructions
   4  *
   5  * Copyright (C) 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
   6  */
   7
   8 #include <asm/neon.h>
   9 #include <asm/simd.h>
  10 #include <crypto/aes.h>
  11 #include <crypto/cbc.h>
  12 #include <crypto/ctr.h>
  13 #include <crypto/internal/simd.h>
  14 #include <crypto/internal/skcipher.h>
  15 #include <crypto/scatterwalk.h>
  16 #include <crypto/xts.h>
  17 #include <linux/module.h>
  18
  19 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  20 MODULE_LICENSE("GPL v2");
  21
  22 MODULE_ALIAS_CRYPTO("ecb(aes)");
  23 MODULE_ALIAS_CRYPTO("cbc(aes)");
  24 MODULE_ALIAS_CRYPTO("ctr(aes)");
  25 MODULE_ALIAS_CRYPTO("xts(aes)");
  26
  27 asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
  28
  29 asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
  30                                   int rounds, int blocks);
  31 asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
  32                                   int rounds, int blocks);
  33
  34 asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
  35                                   int rounds, int blocks, u8 iv[]);
  36
  37 asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
  38                                   int rounds, int blocks, u8 ctr[], u8 final[]);
  39
  40 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
  41                                   int rounds, int blocks, u8 iv[], int);
  42 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
  43                                   int rounds, int blocks, u8 iv[], int);
  44
  45 struct aesbs_ctx {
  46         int     rounds;
  47         u8      rk[13 * (8 * AES_BLOCK_SIZE) + 32] __aligned(AES_BLOCK_SIZE);
  48 };
  49
  50 struct aesbs_cbc_ctx {
  51         struct aesbs_ctx        key;
  52         struct crypto_cipher    *enc_tfm;
  53 };
  54
  55 struct aesbs_xts_ctx {
  56         struct aesbs_ctx        key;
  57         struct crypto_cipher    *cts_tfm;
  58         struct crypto_cipher    *tweak_tfm;
  59 };
  60
  61 struct aesbs_ctr_ctx {
  62         struct aesbs_ctx        key;            /* must be first member */
  63         struct crypto_aes_ctx   fallback;
  64 };
  65
  66 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
  67                         unsigned int key_len)
  68 {
  69         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  70         struct crypto_aes_ctx rk;
  71         int err;
  72
  73         err = aes_expandkey(&rk, in_key, key_len);
  74         if (err)
  75                 return err;
  76
  77         ctx->rounds = 6 + key_len / 4;
  78
  79         kernel_neon_begin();
  80         aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
  81         kernel_neon_end();
  82
  83         return 0;
  84 }
  85
  86 static int __ecb_crypt(struct skcipher_request *req,
  87                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
  88                                   int rounds, int blocks))
  89 {
  90         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  91         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  92         struct skcipher_walk walk;
  93         int err;
  94
  95         err = skcipher_walk_virt(&walk, req, false);
  96
  97         while (walk.nbytes >= AES_BLOCK_SIZE) {
  98                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
  99
 100                 if (walk.nbytes < walk.total)
 101                         blocks = round_down(blocks,
 102                                             walk.stride / AES_BLOCK_SIZE);
 103
 104                 kernel_neon_begin();
 105                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
 106                    ctx->rounds, blocks);
 107                 kernel_neon_end();
 108                 err = skcipher_walk_done(&walk,
 109                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 110         }
 111
 112         return err;
 113 }
 114
 115 static int ecb_encrypt(struct skcipher_request *req)
 116 {
 117         return __ecb_crypt(req, aesbs_ecb_encrypt);
 118 }
 119
 120 static int ecb_decrypt(struct skcipher_request *req)
 121 {
 122         return __ecb_crypt(req, aesbs_ecb_decrypt);
 123 }
 124
 125 static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 126                             unsigned int key_len)
 127 {
 128         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 129         struct crypto_aes_ctx rk;
 130         int err;
 131
 132         err = aes_expandkey(&rk, in_key, key_len);
 133         if (err)
 134                 return err;
 135
 136         ctx->key.rounds = 6 + key_len / 4;
 137
 138         kernel_neon_begin();
 139         aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
 140         kernel_neon_end();
 141         memzero_explicit(&rk, sizeof(rk));
 142
 143         return crypto_cipher_setkey(ctx->enc_tfm, in_key, key_len);
 144 }
 145
 146 static void cbc_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 147 {
 148         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 149
 150         crypto_cipher_encrypt_one(ctx->enc_tfm, dst, src);
 151 }
 152
 153 static int cbc_encrypt(struct skcipher_request *req)
 154 {
 155         return crypto_cbc_encrypt_walk(req, cbc_encrypt_one);
 156 }
 157
 158 static int cbc_decrypt(struct skcipher_request *req)
 159 {
 160         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 161         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 162         struct skcipher_walk walk;
 163         int err;
 164
 165         err = skcipher_walk_virt(&walk, req, false);
 166
 167         while (walk.nbytes >= AES_BLOCK_SIZE) {
 168                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 169
 170                 if (walk.nbytes < walk.total)
 171                         blocks = round_down(blocks,
 172                                             walk.stride / AES_BLOCK_SIZE);
 173
 174                 kernel_neon_begin();
 175                 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 176                                   ctx->key.rk, ctx->key.rounds, blocks,
 177                                   walk.iv);
 178                 kernel_neon_end();
 179                 err = skcipher_walk_done(&walk,
 180                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 181         }
 182
 183         return err;
 184 }
 185
 186 static int cbc_init(struct crypto_tfm *tfm)
 187 {
 188         struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
 189
 190         ctx->enc_tfm = crypto_alloc_cipher("aes", 0, 0);
 191
 192         return PTR_ERR_OR_ZERO(ctx->enc_tfm);
 193 }
 194
 195 static void cbc_exit(struct crypto_tfm *tfm)
 196 {
 197         struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
 198
 199         crypto_free_cipher(ctx->enc_tfm);
 200 }
 201
 202 static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
 203                                  unsigned int key_len)
 204 {
 205         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 206         int err;
 207
 208         err = aes_expandkey(&ctx->fallback, in_key, key_len);
 209         if (err)
 210                 return err;
 211
 212         ctx->key.rounds = 6 + key_len / 4;
 213
 214         kernel_neon_begin();
 215         aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
 216         kernel_neon_end();
 217
 218         return 0;
 219 }
 220
 221 static int ctr_encrypt(struct skcipher_request *req)
 222 {
 223         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 224         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
 225         struct skcipher_walk walk;
 226         u8 buf[AES_BLOCK_SIZE];
 227         int err;
 228
 229         err = skcipher_walk_virt(&walk, req, false);
 230
 231         while (walk.nbytes > 0) {
 232                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 233                 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
 234
 235                 if (walk.nbytes < walk.total) {
 236                         blocks = round_down(blocks,
 237                                             walk.stride / AES_BLOCK_SIZE);
 238                         final = NULL;
 239                 }
 240
 241                 kernel_neon_begin();
 242                 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 243                                   ctx->rk, ctx->rounds, blocks, walk.iv, final);
 244                 kernel_neon_end();
 245
 246                 if (final) {
 247                         u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 248                         u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 249
 250                         crypto_xor_cpy(dst, src, final,
 251                                        walk.total % AES_BLOCK_SIZE);
 252
 253                         err = skcipher_walk_done(&walk, 0);
 254                         break;
 255                 }
 256                 err = skcipher_walk_done(&walk,
 257                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 258         }
 259
 260         return err;
 261 }
 262
 263 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 264 {
 265         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 266         unsigned long flags;
 267
 268         /*
 269          * Temporarily disable interrupts to avoid races where
 270          * cachelines are evicted when the CPU is interrupted
 271          * to do something else.
 272          */
 273         local_irq_save(flags);
 274         aes_encrypt(&ctx->fallback, dst, src);
 275         local_irq_restore(flags);
 276 }
 277
 278 static int ctr_encrypt_sync(struct skcipher_request *req)
 279 {
 280         if (!crypto_simd_usable())
 281                 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
 282
 283         return ctr_encrypt(req);
 284 }
 285
 286 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 287                             unsigned int key_len)
 288 {
 289         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 290         int err;
 291
 292         err = xts_verify_key(tfm, in_key, key_len);
 293         if (err)
 294                 return err;
 295
 296         key_len /= 2;
 297         err = crypto_cipher_setkey(ctx->cts_tfm, in_key, key_len);
 298         if (err)
 299                 return err;
 300         err = crypto_cipher_setkey(ctx->tweak_tfm, in_key + key_len, key_len);
 301         if (err)
 302                 return err;
 303
 304         return aesbs_setkey(tfm, in_key, key_len);
 305 }
 306
 307 static int xts_init(struct crypto_tfm *tfm)
 308 {
 309         struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
 310
 311         ctx->cts_tfm = crypto_alloc_cipher("aes", 0, 0);
 312         if (IS_ERR(ctx->cts_tfm))
 313                 return PTR_ERR(ctx->cts_tfm);
 314
 315         ctx->tweak_tfm = crypto_alloc_cipher("aes", 0, 0);
 316         if (IS_ERR(ctx->tweak_tfm))
 317                 crypto_free_cipher(ctx->cts_tfm);
 318
 319         return PTR_ERR_OR_ZERO(ctx->tweak_tfm);
 320 }
 321
 322 static void xts_exit(struct crypto_tfm *tfm)
 323 {
 324         struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
 325
 326         crypto_free_cipher(ctx->tweak_tfm);
 327         crypto_free_cipher(ctx->cts_tfm);
 328 }
 329
 330 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
 331                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
 332                                   int rounds, int blocks, u8 iv[], int))
 333 {
 334         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 335         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 336         int tail = req->cryptlen % AES_BLOCK_SIZE;
 337         struct skcipher_request subreq;
 338         u8 buf[2 * AES_BLOCK_SIZE];
 339         struct skcipher_walk walk;
 340         int err;
 341
 342         if (req->cryptlen < AES_BLOCK_SIZE)
 343                 return -EINVAL;
 344
 345         if (unlikely(tail)) {
 346                 skcipher_request_set_tfm(&subreq, tfm);
 347                 skcipher_request_set_callback(&subreq,
 348                                               skcipher_request_flags(req),
 349                                               NULL, NULL);
 350                 skcipher_request_set_crypt(&subreq, req->src, req->dst,
 351                                            req->cryptlen - tail, req->iv);
 352                 req = &subreq;
 353         }
 354
 355         err = skcipher_walk_virt(&walk, req, true);
 356         if (err)
 357                 return err;
 358
 359         crypto_cipher_encrypt_one(ctx->tweak_tfm, walk.iv, walk.iv);
 360
 361         while (walk.nbytes >= AES_BLOCK_SIZE) {
 362                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 363                 int reorder_last_tweak = !encrypt && tail > 0;
 364
 365                 if (walk.nbytes < walk.total) {
 366                         blocks = round_down(blocks,
 367                                             walk.stride / AES_BLOCK_SIZE);
 368                         reorder_last_tweak = 0;
 369                 }
 370
 371                 kernel_neon_begin();
 372                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
 373                    ctx->key.rounds, blocks, walk.iv, reorder_last_tweak);
 374                 kernel_neon_end();
 375                 err = skcipher_walk_done(&walk,
 376                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 377         }
 378
 379         if (err || likely(!tail))
 380                 return err;
 381
 382         /* handle ciphertext stealing */
 383         scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
 384                                  AES_BLOCK_SIZE, 0);
 385         memcpy(buf + AES_BLOCK_SIZE, buf, tail);
 386         scatterwalk_map_and_copy(buf, req->src, req->cryptlen, tail, 0);
 387
 388         crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
 389
 390         if (encrypt)
 391                 crypto_cipher_encrypt_one(ctx->cts_tfm, buf, buf);
 392         else
 393                 crypto_cipher_decrypt_one(ctx->cts_tfm, buf, buf);
 394
 395         crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
 396
 397         scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
 398                                  AES_BLOCK_SIZE + tail, 1);
 399         return 0;
 400 }
 401
 402 static int xts_encrypt(struct skcipher_request *req)
 403 {
 404         return __xts_crypt(req, true, aesbs_xts_encrypt);
 405 }
 406
 407 static int xts_decrypt(struct skcipher_request *req)
 408 {
 409         return __xts_crypt(req, false, aesbs_xts_decrypt);
 410 }
 411
 412 static struct skcipher_alg aes_algs[] = { {
 413         .base.cra_name          = "__ecb(aes)",
 414         .base.cra_driver_name   = "__ecb-aes-neonbs",
 415         .base.cra_priority      = 250,
 416         .base.cra_blocksize     = AES_BLOCK_SIZE,
 417         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 418         .base.cra_module        = THIS_MODULE,
 419         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 420
 421         .min_keysize            = AES_MIN_KEY_SIZE,
 422         .max_keysize            = AES_MAX_KEY_SIZE,
 423         .walksize               = 8 * AES_BLOCK_SIZE,
 424         .setkey                 = aesbs_setkey,
 425         .encrypt                = ecb_encrypt,
 426         .decrypt                = ecb_decrypt,
 427 }, {
 428         .base.cra_name          = "__cbc(aes)",
 429         .base.cra_driver_name   = "__cbc-aes-neonbs",
 430         .base.cra_priority      = 250,
 431         .base.cra_blocksize     = AES_BLOCK_SIZE,
 432         .base.cra_ctxsize       = sizeof(struct aesbs_cbc_ctx),
 433         .base.cra_module        = THIS_MODULE,
 434         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 435         .base.cra_init          = cbc_init,
 436         .base.cra_exit          = cbc_exit,
 437
 438         .min_keysize            = AES_MIN_KEY_SIZE,
 439         .max_keysize            = AES_MAX_KEY_SIZE,
 440         .walksize               = 8 * AES_BLOCK_SIZE,
 441         .ivsize                 = AES_BLOCK_SIZE,
 442         .setkey                 = aesbs_cbc_setkey,
 443         .encrypt                = cbc_encrypt,
 444         .decrypt                = cbc_decrypt,
 445 }, {
 446         .base.cra_name          = "__ctr(aes)",
 447         .base.cra_driver_name   = "__ctr-aes-neonbs",
 448         .base.cra_priority      = 250,
 449         .base.cra_blocksize     = 1,
 450         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 451         .base.cra_module        = THIS_MODULE,
 452         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 453
 454         .min_keysize            = AES_MIN_KEY_SIZE,
 455         .max_keysize            = AES_MAX_KEY_SIZE,
 456         .chunksize              = AES_BLOCK_SIZE,
 457         .walksize               = 8 * AES_BLOCK_SIZE,
 458         .ivsize                 = AES_BLOCK_SIZE,
 459         .setkey                 = aesbs_setkey,
 460         .encrypt                = ctr_encrypt,
 461         .decrypt                = ctr_encrypt,
 462 }, {
 463         .base.cra_name          = "ctr(aes)",
 464         .base.cra_driver_name   = "ctr-aes-neonbs-sync",
 465         .base.cra_priority      = 250 - 1,
 466         .base.cra_blocksize     = 1,
 467         .base.cra_ctxsize       = sizeof(struct aesbs_ctr_ctx),
 468         .base.cra_module        = THIS_MODULE,
 469
 470         .min_keysize            = AES_MIN_KEY_SIZE,
 471         .max_keysize            = AES_MAX_KEY_SIZE,
 472         .chunksize              = AES_BLOCK_SIZE,
 473         .walksize               = 8 * AES_BLOCK_SIZE,
 474         .ivsize                 = AES_BLOCK_SIZE,
 475         .setkey                 = aesbs_ctr_setkey_sync,
 476         .encrypt                = ctr_encrypt_sync,
 477         .decrypt                = ctr_encrypt_sync,
 478 }, {
 479         .base.cra_name          = "__xts(aes)",
 480         .base.cra_driver_name   = "__xts-aes-neonbs",
 481         .base.cra_priority      = 250,
 482         .base.cra_blocksize     = AES_BLOCK_SIZE,
 483         .base.cra_ctxsize       = sizeof(struct aesbs_xts_ctx),
 484         .base.cra_module        = THIS_MODULE,
 485         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 486         .base.cra_init          = xts_init,
 487         .base.cra_exit          = xts_exit,
 488
 489         .min_keysize            = 2 * AES_MIN_KEY_SIZE,
 490         .max_keysize            = 2 * AES_MAX_KEY_SIZE,
 491         .walksize               = 8 * AES_BLOCK_SIZE,
 492         .ivsize                 = AES_BLOCK_SIZE,
 493         .setkey                 = aesbs_xts_setkey,
 494         .encrypt                = xts_encrypt,
 495         .decrypt                = xts_decrypt,
 496 } };
 497
 498 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
 499
 500 static void aes_exit(void)
 501 {
 502         int i;
 503
 504         for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
 505                 if (aes_simd_algs[i])
 506                         simd_skcipher_free(aes_simd_algs[i]);
 507
 508         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 509 }
 510
 511 static int __init aes_init(void)
 512 {
 513         struct simd_skcipher_alg *simd;
 514         const char *basename;
 515         const char *algname;
 516         const char *drvname;
 517         int err;
 518         int i;
 519
 520         if (!(elf_hwcap & HWCAP_NEON))
 521                 return -ENODEV;
 522
 523         err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 524         if (err)
 525                 return err;
 526
 527         for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 528                 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
 529                         continue;
 530
 531                 algname = aes_algs[i].base.cra_name + 2;
 532                 drvname = aes_algs[i].base.cra_driver_name + 2;
 533                 basename = aes_algs[i].base.cra_driver_name;
 534                 simd = simd_skcipher_create_compat(algname, drvname, basename);
 535                 err = PTR_ERR(simd);
 536                 if (IS_ERR(simd))
 537                         goto unregister_simds;
 538
 539                 aes_simd_algs[i] = simd;
 540         }
 541         return 0;
 542
 543 unregister_simds:
 544         aes_exit();
 545         return err;
 546 }
 547
 548 late_initcall(aes_init);
 549 module_exit(aes_exit);