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/ctr.h>
  12 #include <crypto/internal/simd.h>
  13 #include <crypto/internal/skcipher.h>
  14 #include <crypto/scatterwalk.h>
  15 #include <crypto/xts.h>
  16 #include <linux/module.h>
  17
  18 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  19 MODULE_LICENSE("GPL v2");
  20
  21 MODULE_ALIAS_CRYPTO("ecb(aes)");
  22 MODULE_ALIAS_CRYPTO("cbc(aes)-all");
  23 MODULE_ALIAS_CRYPTO("ctr(aes)");
  24 MODULE_ALIAS_CRYPTO("xts(aes)");
  25
  26 asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);
  27
  28 asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
  29                                   int rounds, int blocks);
  30 asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
  31                                   int rounds, int blocks);
  32
  33 asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
  34                                   int rounds, int blocks, u8 iv[]);
  35
  36 asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
  37                                   int rounds, int blocks, u8 ctr[], u8 final[]);
  38
  39 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
  40                                   int rounds, int blocks, u8 iv[], int);
  41 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
  42                                   int rounds, int blocks, u8 iv[], int);
  43
  44 struct aesbs_ctx {
  45         int     rounds;
  46         u8      rk[13 * (8 * AES_BLOCK_SIZE) + 32] __aligned(AES_BLOCK_SIZE);
  47 };
  48
  49 struct aesbs_cbc_ctx {
  50         struct aesbs_ctx        key;
  51         struct crypto_skcipher  *enc_tfm;
  52 };
  53
  54 struct aesbs_xts_ctx {
  55         struct aesbs_ctx        key;
  56         struct crypto_cipher    *cts_tfm;
  57         struct crypto_cipher    *tweak_tfm;
  58 };
  59
  60 struct aesbs_ctr_ctx {
  61         struct aesbs_ctx        key;            /* must be first member */
  62         struct crypto_aes_ctx   fallback;
  63 };
  64
  65 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
  66                         unsigned int key_len)
  67 {
  68         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  69         struct crypto_aes_ctx rk;
  70         int err;
  71
  72         err = aes_expandkey(&rk, in_key, key_len);
  73         if (err)
  74                 return err;
  75
  76         ctx->rounds = 6 + key_len / 4;
  77
  78         kernel_neon_begin();
  79         aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
  80         kernel_neon_end();
  81
  82         return 0;
  83 }
  84
  85 static int __ecb_crypt(struct skcipher_request *req,
  86                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
  87                                   int rounds, int blocks))
  88 {
  89         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  90         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  91         struct skcipher_walk walk;
  92         int err;
  93
  94         err = skcipher_walk_virt(&walk, req, false);
  95
  96         while (walk.nbytes >= AES_BLOCK_SIZE) {
  97                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
  98
  99                 if (walk.nbytes < walk.total)
 100                         blocks = round_down(blocks,
 101                                             walk.stride / AES_BLOCK_SIZE);
 102
 103                 kernel_neon_begin();
 104                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
 105                    ctx->rounds, blocks);
 106                 kernel_neon_end();
 107                 err = skcipher_walk_done(&walk,
 108                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 109         }
 110
 111         return err;
 112 }
 113
 114 static int ecb_encrypt(struct skcipher_request *req)
 115 {
 116         return __ecb_crypt(req, aesbs_ecb_encrypt);
 117 }
 118
 119 static int ecb_decrypt(struct skcipher_request *req)
 120 {
 121         return __ecb_crypt(req, aesbs_ecb_decrypt);
 122 }
 123
 124 static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 125                             unsigned int key_len)
 126 {
 127         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 128         struct crypto_aes_ctx rk;
 129         int err;
 130
 131         err = aes_expandkey(&rk, in_key, key_len);
 132         if (err)
 133                 return err;
 134
 135         ctx->key.rounds = 6 + key_len / 4;
 136
 137         kernel_neon_begin();
 138         aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
 139         kernel_neon_end();
 140         memzero_explicit(&rk, sizeof(rk));
 141
 142         return crypto_skcipher_setkey(ctx->enc_tfm, in_key, key_len);
 143 }
 144
 145 static int cbc_encrypt(struct skcipher_request *req)
 146 {
 147         struct skcipher_request *subreq = skcipher_request_ctx(req);
 148         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 149         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 150
 151         skcipher_request_set_tfm(subreq, ctx->enc_tfm);
 152         skcipher_request_set_callback(subreq,
 153                                       skcipher_request_flags(req),
 154                                       NULL, NULL);
 155         skcipher_request_set_crypt(subreq, req->src, req->dst,
 156                                    req->cryptlen, req->iv);
 157
 158         return crypto_skcipher_encrypt(subreq);
 159 }
 160
 161 static int cbc_decrypt(struct skcipher_request *req)
 162 {
 163         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 164         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 165         struct skcipher_walk walk;
 166         int err;
 167
 168         err = skcipher_walk_virt(&walk, req, false);
 169
 170         while (walk.nbytes >= AES_BLOCK_SIZE) {
 171                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 172
 173                 if (walk.nbytes < walk.total)
 174                         blocks = round_down(blocks,
 175                                             walk.stride / AES_BLOCK_SIZE);
 176
 177                 kernel_neon_begin();
 178                 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 179                                   ctx->key.rk, ctx->key.rounds, blocks,
 180                                   walk.iv);
 181                 kernel_neon_end();
 182                 err = skcipher_walk_done(&walk,
 183                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 184         }
 185
 186         return err;
 187 }
 188
 189 static int cbc_init(struct crypto_skcipher *tfm)
 190 {
 191         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 192         unsigned int reqsize;
 193
 194         ctx->enc_tfm = crypto_alloc_skcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC |
 195                                              CRYPTO_ALG_NEED_FALLBACK);
 196         if (IS_ERR(ctx->enc_tfm))
 197                 return PTR_ERR(ctx->enc_tfm);
 198
 199         reqsize = sizeof(struct skcipher_request);
 200         reqsize += crypto_skcipher_reqsize(ctx->enc_tfm);
 201         crypto_skcipher_set_reqsize(tfm, reqsize);
 202
 203         return 0;
 204 }
 205
 206 static void cbc_exit(struct crypto_skcipher *tfm)
 207 {
 208         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 209
 210         crypto_free_skcipher(ctx->enc_tfm);
 211 }
 212
 213 static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
 214                                  unsigned int key_len)
 215 {
 216         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 217         int err;
 218
 219         err = aes_expandkey(&ctx->fallback, in_key, key_len);
 220         if (err)
 221                 return err;
 222
 223         ctx->key.rounds = 6 + key_len / 4;
 224
 225         kernel_neon_begin();
 226         aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
 227         kernel_neon_end();
 228
 229         return 0;
 230 }
 231
 232 static int ctr_encrypt(struct skcipher_request *req)
 233 {
 234         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 235         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
 236         struct skcipher_walk walk;
 237         u8 buf[AES_BLOCK_SIZE];
 238         int err;
 239
 240         err = skcipher_walk_virt(&walk, req, false);
 241
 242         while (walk.nbytes > 0) {
 243                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 244                 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
 245
 246                 if (walk.nbytes < walk.total) {
 247                         blocks = round_down(blocks,
 248                                             walk.stride / AES_BLOCK_SIZE);
 249                         final = NULL;
 250                 }
 251
 252                 kernel_neon_begin();
 253                 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 254                                   ctx->rk, ctx->rounds, blocks, walk.iv, final);
 255                 kernel_neon_end();
 256
 257                 if (final) {
 258                         u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 259                         u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 260
 261                         crypto_xor_cpy(dst, src, final,
 262                                        walk.total % AES_BLOCK_SIZE);
 263
 264                         err = skcipher_walk_done(&walk, 0);
 265                         break;
 266                 }
 267                 err = skcipher_walk_done(&walk,
 268                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 269         }
 270
 271         return err;
 272 }
 273
 274 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 275 {
 276         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 277         unsigned long flags;
 278
 279         /*
 280          * Temporarily disable interrupts to avoid races where
 281          * cachelines are evicted when the CPU is interrupted
 282          * to do something else.
 283          */
 284         local_irq_save(flags);
 285         aes_encrypt(&ctx->fallback, dst, src);
 286         local_irq_restore(flags);
 287 }
 288
 289 static int ctr_encrypt_sync(struct skcipher_request *req)
 290 {
 291         if (!crypto_simd_usable())
 292                 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
 293
 294         return ctr_encrypt(req);
 295 }
 296
 297 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 298                             unsigned int key_len)
 299 {
 300         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 301         int err;
 302
 303         err = xts_verify_key(tfm, in_key, key_len);
 304         if (err)
 305                 return err;
 306
 307         key_len /= 2;
 308         err = crypto_cipher_setkey(ctx->cts_tfm, in_key, key_len);
 309         if (err)
 310                 return err;
 311         err = crypto_cipher_setkey(ctx->tweak_tfm, in_key + key_len, key_len);
 312         if (err)
 313                 return err;
 314
 315         return aesbs_setkey(tfm, in_key, key_len);
 316 }
 317
 318 static int xts_init(struct crypto_skcipher *tfm)
 319 {
 320         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 321
 322         ctx->cts_tfm = crypto_alloc_cipher("aes", 0, 0);
 323         if (IS_ERR(ctx->cts_tfm))
 324                 return PTR_ERR(ctx->cts_tfm);
 325
 326         ctx->tweak_tfm = crypto_alloc_cipher("aes", 0, 0);
 327         if (IS_ERR(ctx->tweak_tfm))
 328                 crypto_free_cipher(ctx->cts_tfm);
 329
 330         return PTR_ERR_OR_ZERO(ctx->tweak_tfm);
 331 }
 332
 333 static void xts_exit(struct crypto_skcipher *tfm)
 334 {
 335         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 336
 337         crypto_free_cipher(ctx->tweak_tfm);
 338         crypto_free_cipher(ctx->cts_tfm);
 339 }
 340
 341 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
 342                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
 343                                   int rounds, int blocks, u8 iv[], int))
 344 {
 345         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 346         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 347         int tail = req->cryptlen % AES_BLOCK_SIZE;
 348         struct skcipher_request subreq;
 349         u8 buf[2 * AES_BLOCK_SIZE];
 350         struct skcipher_walk walk;
 351         int err;
 352
 353         if (req->cryptlen < AES_BLOCK_SIZE)
 354                 return -EINVAL;
 355
 356         if (unlikely(tail)) {
 357                 skcipher_request_set_tfm(&subreq, tfm);
 358                 skcipher_request_set_callback(&subreq,
 359                                               skcipher_request_flags(req),
 360                                               NULL, NULL);
 361                 skcipher_request_set_crypt(&subreq, req->src, req->dst,
 362                                            req->cryptlen - tail, req->iv);
 363                 req = &subreq;
 364         }
 365
 366         err = skcipher_walk_virt(&walk, req, true);
 367         if (err)
 368                 return err;
 369
 370         crypto_cipher_encrypt_one(ctx->tweak_tfm, walk.iv, walk.iv);
 371
 372         while (walk.nbytes >= AES_BLOCK_SIZE) {
 373                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 374                 int reorder_last_tweak = !encrypt && tail > 0;
 375
 376                 if (walk.nbytes < walk.total) {
 377                         blocks = round_down(blocks,
 378                                             walk.stride / AES_BLOCK_SIZE);
 379                         reorder_last_tweak = 0;
 380                 }
 381
 382                 kernel_neon_begin();
 383                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->key.rk,
 384                    ctx->key.rounds, blocks, walk.iv, reorder_last_tweak);
 385                 kernel_neon_end();
 386                 err = skcipher_walk_done(&walk,
 387                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 388         }
 389
 390         if (err || likely(!tail))
 391                 return err;
 392
 393         /* handle ciphertext stealing */
 394         scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
 395                                  AES_BLOCK_SIZE, 0);
 396         memcpy(buf + AES_BLOCK_SIZE, buf, tail);
 397         scatterwalk_map_and_copy(buf, req->src, req->cryptlen, tail, 0);
 398
 399         crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
 400
 401         if (encrypt)
 402                 crypto_cipher_encrypt_one(ctx->cts_tfm, buf, buf);
 403         else
 404                 crypto_cipher_decrypt_one(ctx->cts_tfm, buf, buf);
 405
 406         crypto_xor(buf, req->iv, AES_BLOCK_SIZE);
 407
 408         scatterwalk_map_and_copy(buf, req->dst, req->cryptlen - AES_BLOCK_SIZE,
 409                                  AES_BLOCK_SIZE + tail, 1);
 410         return 0;
 411 }
 412
 413 static int xts_encrypt(struct skcipher_request *req)
 414 {
 415         return __xts_crypt(req, true, aesbs_xts_encrypt);
 416 }
 417
 418 static int xts_decrypt(struct skcipher_request *req)
 419 {
 420         return __xts_crypt(req, false, aesbs_xts_decrypt);
 421 }
 422
 423 static struct skcipher_alg aes_algs[] = { {
 424         .base.cra_name          = "__ecb(aes)",
 425         .base.cra_driver_name   = "__ecb-aes-neonbs",
 426         .base.cra_priority      = 250,
 427         .base.cra_blocksize     = AES_BLOCK_SIZE,
 428         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 429         .base.cra_module        = THIS_MODULE,
 430         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 431
 432         .min_keysize            = AES_MIN_KEY_SIZE,
 433         .max_keysize            = AES_MAX_KEY_SIZE,
 434         .walksize               = 8 * AES_BLOCK_SIZE,
 435         .setkey                 = aesbs_setkey,
 436         .encrypt                = ecb_encrypt,
 437         .decrypt                = ecb_decrypt,
 438 }, {
 439         .base.cra_name          = "__cbc(aes)",
 440         .base.cra_driver_name   = "__cbc-aes-neonbs",
 441         .base.cra_priority      = 250,
 442         .base.cra_blocksize     = AES_BLOCK_SIZE,
 443         .base.cra_ctxsize       = sizeof(struct aesbs_cbc_ctx),
 444         .base.cra_module        = THIS_MODULE,
 445         .base.cra_flags         = CRYPTO_ALG_INTERNAL |
 446                                   CRYPTO_ALG_NEED_FALLBACK,
 447
 448         .min_keysize            = AES_MIN_KEY_SIZE,
 449         .max_keysize            = AES_MAX_KEY_SIZE,
 450         .walksize               = 8 * AES_BLOCK_SIZE,
 451         .ivsize                 = AES_BLOCK_SIZE,
 452         .setkey                 = aesbs_cbc_setkey,
 453         .encrypt                = cbc_encrypt,
 454         .decrypt                = cbc_decrypt,
 455         .init                   = cbc_init,
 456         .exit                   = cbc_exit,
 457 }, {
 458         .base.cra_name          = "__ctr(aes)",
 459         .base.cra_driver_name   = "__ctr-aes-neonbs",
 460         .base.cra_priority      = 250,
 461         .base.cra_blocksize     = 1,
 462         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 463         .base.cra_module        = THIS_MODULE,
 464         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 465
 466         .min_keysize            = AES_MIN_KEY_SIZE,
 467         .max_keysize            = AES_MAX_KEY_SIZE,
 468         .chunksize              = AES_BLOCK_SIZE,
 469         .walksize               = 8 * AES_BLOCK_SIZE,
 470         .ivsize                 = AES_BLOCK_SIZE,
 471         .setkey                 = aesbs_setkey,
 472         .encrypt                = ctr_encrypt,
 473         .decrypt                = ctr_encrypt,
 474 }, {
 475         .base.cra_name          = "ctr(aes)",
 476         .base.cra_driver_name   = "ctr-aes-neonbs-sync",
 477         .base.cra_priority      = 250 - 1,
 478         .base.cra_blocksize     = 1,
 479         .base.cra_ctxsize       = sizeof(struct aesbs_ctr_ctx),
 480         .base.cra_module        = THIS_MODULE,
 481
 482         .min_keysize            = AES_MIN_KEY_SIZE,
 483         .max_keysize            = AES_MAX_KEY_SIZE,
 484         .chunksize              = AES_BLOCK_SIZE,
 485         .walksize               = 8 * AES_BLOCK_SIZE,
 486         .ivsize                 = AES_BLOCK_SIZE,
 487         .setkey                 = aesbs_ctr_setkey_sync,
 488         .encrypt                = ctr_encrypt_sync,
 489         .decrypt                = ctr_encrypt_sync,
 490 }, {
 491         .base.cra_name          = "__xts(aes)",
 492         .base.cra_driver_name   = "__xts-aes-neonbs",
 493         .base.cra_priority      = 250,
 494         .base.cra_blocksize     = AES_BLOCK_SIZE,
 495         .base.cra_ctxsize       = sizeof(struct aesbs_xts_ctx),
 496         .base.cra_module        = THIS_MODULE,
 497         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 498
 499         .min_keysize            = 2 * AES_MIN_KEY_SIZE,
 500         .max_keysize            = 2 * AES_MAX_KEY_SIZE,
 501         .walksize               = 8 * AES_BLOCK_SIZE,
 502         .ivsize                 = AES_BLOCK_SIZE,
 503         .setkey                 = aesbs_xts_setkey,
 504         .encrypt                = xts_encrypt,
 505         .decrypt                = xts_decrypt,
 506         .init                   = xts_init,
 507         .exit                   = xts_exit,
 508 } };
 509
 510 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
 511
 512 static void aes_exit(void)
 513 {
 514         int i;
 515
 516         for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
 517                 if (aes_simd_algs[i])
 518                         simd_skcipher_free(aes_simd_algs[i]);
 519
 520         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 521 }
 522
 523 static int __init aes_init(void)
 524 {
 525         struct simd_skcipher_alg *simd;
 526         const char *basename;
 527         const char *algname;
 528         const char *drvname;
 529         int err;
 530         int i;
 531
 532         if (!(elf_hwcap & HWCAP_NEON))
 533                 return -ENODEV;
 534
 535         err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 536         if (err)
 537                 return err;
 538
 539         for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 540                 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
 541                         continue;
 542
 543                 algname = aes_algs[i].base.cra_name + 2;
 544                 drvname = aes_algs[i].base.cra_driver_name + 2;
 545                 basename = aes_algs[i].base.cra_driver_name;
 546                 simd = simd_skcipher_create_compat(algname, drvname, basename);
 547                 err = PTR_ERR(simd);
 548                 if (IS_ERR(simd))
 549                         goto unregister_simds;
 550
 551                 aes_simd_algs[i] = simd;
 552         }
 553         return 0;
 554
 555 unregister_simds:
 556         aes_exit();
 557         return err;
 558 }
 559
 560 late_initcall(aes_init);
 561 module_exit(aes_exit);