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
 142         return crypto_cipher_setkey(ctx->enc_tfm, in_key, key_len);
 143 }
 144
 145 static void cbc_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 146 {
 147         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 148
 149         crypto_cipher_encrypt_one(ctx->enc_tfm, dst, src);
 150 }
 151
 152 static int cbc_encrypt(struct skcipher_request *req)
 153 {
 154         return crypto_cbc_encrypt_walk(req, cbc_encrypt_one);
 155 }
 156
 157 static int cbc_decrypt(struct skcipher_request *req)
 158 {
 159         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 160         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 161         struct skcipher_walk walk;
 162         int err;
 163
 164         err = skcipher_walk_virt(&walk, req, false);
 165
 166         while (walk.nbytes >= AES_BLOCK_SIZE) {
 167                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 168
 169                 if (walk.nbytes < walk.total)
 170                         blocks = round_down(blocks,
 171                                             walk.stride / AES_BLOCK_SIZE);
 172
 173                 kernel_neon_begin();
 174                 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 175                                   ctx->key.rk, ctx->key.rounds, blocks,
 176                                   walk.iv);
 177                 kernel_neon_end();
 178                 err = skcipher_walk_done(&walk,
 179                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 180         }
 181
 182         return err;
 183 }
 184
 185 static int cbc_init(struct crypto_tfm *tfm)
 186 {
 187         struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
 188
 189         ctx->enc_tfm = crypto_alloc_cipher("aes", 0, 0);
 190
 191         return PTR_ERR_OR_ZERO(ctx->enc_tfm);
 192 }
 193
 194 static void cbc_exit(struct crypto_tfm *tfm)
 195 {
 196         struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
 197
 198         crypto_free_cipher(ctx->enc_tfm);
 199 }
 200
 201 static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
 202                                  unsigned int key_len)
 203 {
 204         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 205         int err;
 206
 207         err = aes_expandkey(&ctx->fallback, in_key, key_len);
 208         if (err)
 209                 return err;
 210
 211         ctx->key.rounds = 6 + key_len / 4;
 212
 213         kernel_neon_begin();
 214         aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
 215         kernel_neon_end();
 216
 217         return 0;
 218 }
 219
 220 static int ctr_encrypt(struct skcipher_request *req)
 221 {
 222         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 223         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
 224         struct skcipher_walk walk;
 225         u8 buf[AES_BLOCK_SIZE];
 226         int err;
 227
 228         err = skcipher_walk_virt(&walk, req, false);
 229
 230         while (walk.nbytes > 0) {
 231                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 232                 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
 233
 234                 if (walk.nbytes < walk.total) {
 235                         blocks = round_down(blocks,
 236                                             walk.stride / AES_BLOCK_SIZE);
 237                         final = NULL;
 238                 }
 239
 240                 kernel_neon_begin();
 241                 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 242                                   ctx->rk, ctx->rounds, blocks, walk.iv, final);
 243                 kernel_neon_end();
 244
 245                 if (final) {
 246                         u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 247                         u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 248
 249                         crypto_xor_cpy(dst, src, final,
 250                                        walk.total % AES_BLOCK_SIZE);
 251
 252                         err = skcipher_walk_done(&walk, 0);
 253                         break;
 254                 }
 255                 err = skcipher_walk_done(&walk,
 256                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 257         }
 258
 259         return err;
 260 }
 261
 262 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 263 {
 264         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 265         unsigned long flags;
 266
 267         /*
 268          * Temporarily disable interrupts to avoid races where
 269          * cachelines are evicted when the CPU is interrupted
 270          * to do something else.
 271          */
 272         local_irq_save(flags);
 273         aes_encrypt(&ctx->fallback, dst, src);
 274         local_irq_restore(flags);
 275 }
 276
 277 static int ctr_encrypt_sync(struct skcipher_request *req)
 278 {
 279         if (!crypto_simd_usable())
 280                 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
 281
 282         return ctr_encrypt(req);
 283 }
 284
 285 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 286                             unsigned int key_len)
 287 {
 288         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 289         int err;
 290
 291         err = xts_verify_key(tfm, in_key, key_len);
 292         if (err)
 293                 return err;
 294
 295         key_len /= 2;
 296         err = crypto_cipher_setkey(ctx->cts_tfm, in_key, key_len);
 297         if (err)
 298                 return err;
 299         err = crypto_cipher_setkey(ctx->tweak_tfm, in_key + key_len, key_len);
 300         if (err)
 301                 return err;
 302
 303         return aesbs_setkey(tfm, in_key, key_len);
 304 }
 305
 306 static int xts_init(struct crypto_tfm *tfm)
 307 {
 308         struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
 309
 310         ctx->cts_tfm = crypto_alloc_cipher("aes", 0, 0);
 311         if (IS_ERR(ctx->cts_tfm))
 312                 return PTR_ERR(ctx->cts_tfm);
 313
 314         ctx->tweak_tfm = crypto_alloc_cipher("aes", 0, 0);
 315         if (IS_ERR(ctx->tweak_tfm))
 316                 crypto_free_cipher(ctx->cts_tfm);
 317
 318         return PTR_ERR_OR_ZERO(ctx->tweak_tfm);
 319 }
 320
 321 static void xts_exit(struct crypto_tfm *tfm)
 322 {
 323         struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
 324
 325         crypto_free_cipher(ctx->tweak_tfm);
 326         crypto_free_cipher(ctx->cts_tfm);
 327 }
 328
 329 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
 330                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
 331                                   int rounds, int blocks, u8 iv[], int))
 332 {
 333         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 334         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 335         int tail = req->cryptlen % AES_BLOCK_SIZE;
 336         struct skcipher_request subreq;
 337         u8 buf[2 * AES_BLOCK_SIZE];
 338         struct skcipher_walk walk;
 339         int err;
 340
 341         if (req->cryptlen < AES_BLOCK_SIZE)
 342                 return -EINVAL;
 343
 344         if (unlikely(tail)) {
 345                 skcipher_request_set_tfm(&subreq, tfm);
 346                 skcipher_request_set_callback(&subreq,
 347                                               skcipher_request_flags(req),
 348                                               NULL, NULL);
 349                 skcipher_request_set_crypt(&subreq, req->src, req->dst,
 350                                            req->cryptlen - tail, req->iv);
 351                 req = &subreq;
 352         }
 353
 354         err = skcipher_walk_virt(&walk, req, true);
 355         if (err)
 356                 return err;
 357
 358         crypto_cipher_encrypt_one(ctx->tweak_tfm, walk.iv, walk.iv);
 359
 360         while (walk.nbytes >= AES_BLOCK_SIZE) {
 361                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 362                 int reorder_last_tweak = !encrypt && tail > 0;
 363
 364                 if (walk.nbytes < walk.total) {
 365                         blocks = round_down(blocks,
 366                                             walk.stride / AES_BLOCK_SIZE);
 367                         reorder_last_tweak = 0;
 368                 }
 369
 370                 kernel_neon_begin();
 371                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
 372                    ctx->key.rounds, blocks, walk.iv, reorder_last_tweak);
 373                 kernel_neon_end();
 374                 err = skcipher_walk_done(&walk,
 375                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 376         }
 377
 378         if (err || likely(!tail))
 379                 return err;
 380
 381         /* handle ciphertext stealing */
 382         scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
 383                                  AES_BLOCK_SIZE, 0);
 384         memcpy(buf + AES_BLOCK_SIZE, buf, tail);
 385         scatterwalk_map_and_copy(buf, req->src, req->cryptlen, tail, 0);
 386
 387         crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
 388
 389         if (encrypt)
 390                 crypto_cipher_encrypt_one(ctx->cts_tfm, buf, buf);
 391         else
 392                 crypto_cipher_decrypt_one(ctx->cts_tfm, buf, buf);
 393
 394         crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
 395
 396         scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
 397                                  AES_BLOCK_SIZE + tail, 1);
 398         return 0;
 399 }
 400
 401 static int xts_encrypt(struct skcipher_request *req)
 402 {
 403         return __xts_crypt(req, true, aesbs_xts_encrypt);
 404 }
 405
 406 static int xts_decrypt(struct skcipher_request *req)
 407 {
 408         return __xts_crypt(req, false, aesbs_xts_decrypt);
 409 }
 410
 411 static struct skcipher_alg aes_algs[] = { {
 412         .base.cra_name          = "__ecb(aes)",
 413         .base.cra_driver_name   = "__ecb-aes-neonbs",
 414         .base.cra_priority      = 250,
 415         .base.cra_blocksize     = AES_BLOCK_SIZE,
 416         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 417         .base.cra_module        = THIS_MODULE,
 418         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 419
 420         .min_keysize            = AES_MIN_KEY_SIZE,
 421         .max_keysize            = AES_MAX_KEY_SIZE,
 422         .walksize               = 8 * AES_BLOCK_SIZE,
 423         .setkey                 = aesbs_setkey,
 424         .encrypt                = ecb_encrypt,
 425         .decrypt                = ecb_decrypt,
 426 }, {
 427         .base.cra_name          = "__cbc(aes)",
 428         .base.cra_driver_name   = "__cbc-aes-neonbs",
 429         .base.cra_priority      = 250,
 430         .base.cra_blocksize     = AES_BLOCK_SIZE,
 431         .base.cra_ctxsize       = sizeof(struct aesbs_cbc_ctx),
 432         .base.cra_module        = THIS_MODULE,
 433         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 434         .base.cra_init          = cbc_init,
 435         .base.cra_exit          = cbc_exit,
 436
 437         .min_keysize            = AES_MIN_KEY_SIZE,
 438         .max_keysize            = AES_MAX_KEY_SIZE,
 439         .walksize               = 8 * AES_BLOCK_SIZE,
 440         .ivsize                 = AES_BLOCK_SIZE,
 441         .setkey                 = aesbs_cbc_setkey,
 442         .encrypt                = cbc_encrypt,
 443         .decrypt                = cbc_decrypt,
 444 }, {
 445         .base.cra_name          = "__ctr(aes)",
 446         .base.cra_driver_name   = "__ctr-aes-neonbs",
 447         .base.cra_priority      = 250,
 448         .base.cra_blocksize     = 1,
 449         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 450         .base.cra_module        = THIS_MODULE,
 451         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 452
 453         .min_keysize            = AES_MIN_KEY_SIZE,
 454         .max_keysize            = AES_MAX_KEY_SIZE,
 455         .chunksize              = AES_BLOCK_SIZE,
 456         .walksize               = 8 * AES_BLOCK_SIZE,
 457         .ivsize                 = AES_BLOCK_SIZE,
 458         .setkey                 = aesbs_setkey,
 459         .encrypt                = ctr_encrypt,
 460         .decrypt                = ctr_encrypt,
 461 }, {
 462         .base.cra_name          = "ctr(aes)",
 463         .base.cra_driver_name   = "ctr-aes-neonbs-sync",
 464         .base.cra_priority      = 250 - 1,
 465         .base.cra_blocksize     = 1,
 466         .base.cra_ctxsize       = sizeof(struct aesbs_ctr_ctx),
 467         .base.cra_module        = THIS_MODULE,
 468
 469         .min_keysize            = AES_MIN_KEY_SIZE,
 470         .max_keysize            = AES_MAX_KEY_SIZE,
 471         .chunksize              = AES_BLOCK_SIZE,
 472         .walksize               = 8 * AES_BLOCK_SIZE,
 473         .ivsize                 = AES_BLOCK_SIZE,
 474         .setkey                 = aesbs_ctr_setkey_sync,
 475         .encrypt                = ctr_encrypt_sync,
 476         .decrypt                = ctr_encrypt_sync,
 477 }, {
 478         .base.cra_name          = "__xts(aes)",
 479         .base.cra_driver_name   = "__xts-aes-neonbs",
 480         .base.cra_priority      = 250,
 481         .base.cra_blocksize     = AES_BLOCK_SIZE,
 482         .base.cra_ctxsize       = sizeof(struct aesbs_xts_ctx),
 483         .base.cra_module        = THIS_MODULE,
 484         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 485         .base.cra_init          = xts_init,
 486         .base.cra_exit          = xts_exit,
 487
 488         .min_keysize            = 2 * AES_MIN_KEY_SIZE,
 489         .max_keysize            = 2 * AES_MAX_KEY_SIZE,
 490         .walksize               = 8 * AES_BLOCK_SIZE,
 491         .ivsize                 = AES_BLOCK_SIZE,
 492         .setkey                 = aesbs_xts_setkey,
 493         .encrypt                = xts_encrypt,
 494         .decrypt                = xts_decrypt,
 495 } };
 496
 497 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
 498
 499 static void aes_exit(void)
 500 {
 501         int i;
 502
 503         for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
 504                 if (aes_simd_algs[i])
 505                         simd_skcipher_free(aes_simd_algs[i]);
 506
 507         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 508 }
 509
 510 static int __init aes_init(void)
 511 {
 512         struct simd_skcipher_alg *simd;
 513         const char *basename;
 514         const char *algname;
 515         const char *drvname;
 516         int err;
 517         int i;
 518
 519         if (!(elf_hwcap & HWCAP_NEON))
 520                 return -ENODEV;
 521
 522         err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 523         if (err)
 524                 return err;
 525
 526         for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 527                 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
 528                         continue;
 529
 530                 algname = aes_algs[i].base.cra_name + 2;
 531                 drvname = aes_algs[i].base.cra_driver_name + 2;
 532                 basename = aes_algs[i].base.cra_driver_name;
 533                 simd = simd_skcipher_create_compat(algname, drvname, basename);
 534                 err = PTR_ERR(simd);
 535                 if (IS_ERR(simd))
 536                         goto unregister_simds;
 537
 538                 aes_simd_algs[i] = simd;
 539         }
 540         return 0;
 541
 542 unregister_simds:
 543         aes_exit();
 544         return err;
 545 }
 546
 547 late_initcall(aes_init);
 548 module_exit(aes_exit);