arch/arm64/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) 2016 - 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)");
  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 iv[], u8 final[]);
  38
  39 asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
  40                                   int rounds, int blocks, u8 iv[]);
  41 asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
  42                                   int rounds, int blocks, u8 iv[]);
  43
  44 /* borrowed from aes-neon-blk.ko */
  45 asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
  46                                      int rounds, int blocks);
  47 asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
  48                                      int rounds, int blocks, u8 iv[]);
  49 asmlinkage void neon_aes_xts_encrypt(u8 out[], u8 const in[],
  50                                      u32 const rk1[], int rounds, int bytes,
  51                                      u32 const rk2[], u8 iv[], int first);
  52 asmlinkage void neon_aes_xts_decrypt(u8 out[], u8 const in[],
  53                                      u32 const rk1[], int rounds, int bytes,
  54                                      u32 const rk2[], u8 iv[], int first);
  55
  56 struct aesbs_ctx {
  57         u8      rk[13 * (8 * AES_BLOCK_SIZE) + 32];
  58         int     rounds;
  59 } __aligned(AES_BLOCK_SIZE);
  60
  61 struct aesbs_cbc_ctx {
  62         struct aesbs_ctx        key;
  63         u32                     enc[AES_MAX_KEYLENGTH_U32];
  64 };
  65
  66 struct aesbs_ctr_ctx {
  67         struct aesbs_ctx        key;            /* must be first member */
  68         struct crypto_aes_ctx   fallback;
  69 };
  70
  71 struct aesbs_xts_ctx {
  72         struct aesbs_ctx        key;
  73         u32                     twkey[AES_MAX_KEYLENGTH_U32];
  74         struct crypto_aes_ctx   cts;
  75 };
  76
  77 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
  78                         unsigned int key_len)
  79 {
  80         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  81         struct crypto_aes_ctx rk;
  82         int err;
  83
  84         err = aes_expandkey(&rk, in_key, key_len);
  85         if (err)
  86                 return err;
  87
  88         ctx->rounds = 6 + key_len / 4;
  89
  90         kernel_neon_begin();
  91         aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
  92         kernel_neon_end();
  93
  94         return 0;
  95 }
  96
  97 static int __ecb_crypt(struct skcipher_request *req,
  98                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
  99                                   int rounds, int blocks))
 100 {
 101         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 102         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
 103         struct skcipher_walk walk;
 104         int err;
 105
 106         err = skcipher_walk_virt(&walk, req, false);
 107
 108         while (walk.nbytes >= AES_BLOCK_SIZE) {
 109                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 110
 111                 if (walk.nbytes < walk.total)
 112                         blocks = round_down(blocks,
 113                                             walk.stride / AES_BLOCK_SIZE);
 114
 115                 kernel_neon_begin();
 116                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
 117                    ctx->rounds, blocks);
 118                 kernel_neon_end();
 119                 err = skcipher_walk_done(&walk,
 120                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 121         }
 122
 123         return err;
 124 }
 125
 126 static int ecb_encrypt(struct skcipher_request *req)
 127 {
 128         return __ecb_crypt(req, aesbs_ecb_encrypt);
 129 }
 130
 131 static int ecb_decrypt(struct skcipher_request *req)
 132 {
 133         return __ecb_crypt(req, aesbs_ecb_decrypt);
 134 }
 135
 136 static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 137                             unsigned int key_len)
 138 {
 139         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 140         struct crypto_aes_ctx rk;
 141         int err;
 142
 143         err = aes_expandkey(&rk, in_key, key_len);
 144         if (err)
 145                 return err;
 146
 147         ctx->key.rounds = 6 + key_len / 4;
 148
 149         memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));
 150
 151         kernel_neon_begin();
 152         aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
 153         kernel_neon_end();
 154         memzero_explicit(&rk, sizeof(rk));
 155
 156         return 0;
 157 }
 158
 159 static int cbc_encrypt(struct skcipher_request *req)
 160 {
 161         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 162         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 163         struct skcipher_walk walk;
 164         int err;
 165
 166         err = skcipher_walk_virt(&walk, req, false);
 167
 168         while (walk.nbytes >= AES_BLOCK_SIZE) {
 169                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 170
 171                 /* fall back to the non-bitsliced NEON implementation */
 172                 kernel_neon_begin();
 173                 neon_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 174                                      ctx->enc, ctx->key.rounds, blocks,
 175                                      walk.iv);
 176                 kernel_neon_end();
 177                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 178         }
 179         return err;
 180 }
 181
 182 static int cbc_decrypt(struct skcipher_request *req)
 183 {
 184         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 185         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 186         struct skcipher_walk walk;
 187         int err;
 188
 189         err = skcipher_walk_virt(&walk, req, false);
 190
 191         while (walk.nbytes >= AES_BLOCK_SIZE) {
 192                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 193
 194                 if (walk.nbytes < walk.total)
 195                         blocks = round_down(blocks,
 196                                             walk.stride / AES_BLOCK_SIZE);
 197
 198                 kernel_neon_begin();
 199                 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 200                                   ctx->key.rk, ctx->key.rounds, blocks,
 201                                   walk.iv);
 202                 kernel_neon_end();
 203                 err = skcipher_walk_done(&walk,
 204                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 205         }
 206
 207         return err;
 208 }
 209
 210 static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
 211                                  unsigned int key_len)
 212 {
 213         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 214         int err;
 215
 216         err = aes_expandkey(&ctx->fallback, in_key, key_len);
 217         if (err)
 218                 return err;
 219
 220         ctx->key.rounds = 6 + key_len / 4;
 221
 222         kernel_neon_begin();
 223         aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
 224         kernel_neon_end();
 225
 226         return 0;
 227 }
 228
 229 static int ctr_encrypt(struct skcipher_request *req)
 230 {
 231         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 232         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
 233         struct skcipher_walk walk;
 234         u8 buf[AES_BLOCK_SIZE];
 235         int err;
 236
 237         err = skcipher_walk_virt(&walk, req, false);
 238
 239         while (walk.nbytes > 0) {
 240                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 241                 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
 242
 243                 if (walk.nbytes < walk.total) {
 244                         blocks = round_down(blocks,
 245                                             walk.stride / AES_BLOCK_SIZE);
 246                         final = NULL;
 247                 }
 248
 249                 kernel_neon_begin();
 250                 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 251                                   ctx->rk, ctx->rounds, blocks, walk.iv, final);
 252                 kernel_neon_end();
 253
 254                 if (final) {
 255                         u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 256                         u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 257
 258                         crypto_xor_cpy(dst, src, final,
 259                                        walk.total % AES_BLOCK_SIZE);
 260
 261                         err = skcipher_walk_done(&walk, 0);
 262                         break;
 263                 }
 264                 err = skcipher_walk_done(&walk,
 265                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 266         }
 267         return err;
 268 }
 269
 270 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 271                             unsigned int key_len)
 272 {
 273         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 274         struct crypto_aes_ctx rk;
 275         int err;
 276
 277         err = xts_verify_key(tfm, in_key, key_len);
 278         if (err)
 279                 return err;
 280
 281         key_len /= 2;
 282         err = aes_expandkey(&ctx->cts, in_key, key_len);
 283         if (err)
 284                 return err;
 285
 286         err = aes_expandkey(&rk, in_key + key_len, key_len);
 287         if (err)
 288                 return err;
 289
 290         memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));
 291
 292         return aesbs_setkey(tfm, in_key, key_len);
 293 }
 294
 295 static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
 296 {
 297         struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
 298         unsigned long flags;
 299
 300         /*
 301          * Temporarily disable interrupts to avoid races where
 302          * cachelines are evicted when the CPU is interrupted
 303          * to do something else.
 304          */
 305         local_irq_save(flags);
 306         aes_encrypt(&ctx->fallback, dst, src);
 307         local_irq_restore(flags);
 308 }
 309
 310 static int ctr_encrypt_sync(struct skcipher_request *req)
 311 {
 312         if (!crypto_simd_usable())
 313                 return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
 314
 315         return ctr_encrypt(req);
 316 }
 317
 318 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
 319                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
 320                                   int rounds, int blocks, u8 iv[]))
 321 {
 322         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 323         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 324         int tail = req->cryptlen % (8 * AES_BLOCK_SIZE);
 325         struct scatterlist sg_src[2], sg_dst[2];
 326         struct skcipher_request subreq;
 327         struct scatterlist *src, *dst;
 328         struct skcipher_walk walk;
 329         int nbytes, err;
 330         int first = 1;
 331         u8 *out, *in;
 332
 333         if (req->cryptlen < AES_BLOCK_SIZE)
 334                 return -EINVAL;
 335
 336         /* ensure that the cts tail is covered by a single step */
 337         if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) {
 338                 int xts_blocks = DIV_ROUND_UP(req->cryptlen,
 339                                               AES_BLOCK_SIZE) - 2;
 340
 341                 skcipher_request_set_tfm(&subreq, tfm);
 342                 skcipher_request_set_callback(&subreq,
 343                                               skcipher_request_flags(req),
 344                                               NULL, NULL);
 345                 skcipher_request_set_crypt(&subreq, req->src, req->dst,
 346                                            xts_blocks * AES_BLOCK_SIZE,
 347                                            req->iv);
 348                 req = &subreq;
 349         } else {
 350                 tail = 0;
 351         }
 352
 353         err = skcipher_walk_virt(&walk, req, false);
 354         if (err)
 355                 return err;
 356
 357         while (walk.nbytes >= AES_BLOCK_SIZE) {
 358                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 359
 360                 if (walk.nbytes < walk.total || walk.nbytes % AES_BLOCK_SIZE)
 361                         blocks = round_down(blocks,
 362                                             walk.stride / AES_BLOCK_SIZE);
 363
 364                 out = walk.dst.virt.addr;
 365                 in = walk.src.virt.addr;
 366                 nbytes = walk.nbytes;
 367
 368                 kernel_neon_begin();
 369                 if (likely(blocks > 6)) { /* plain NEON is faster otherwise */
 370                         if (first)
 371                                 neon_aes_ecb_encrypt(walk.iv, walk.iv,
 372                                                      ctx->twkey,
 373                                                      ctx->key.rounds, 1);
 374                         first = 0;
 375
 376                         fn(out, in, ctx->key.rk, ctx->key.rounds, blocks,
 377                            walk.iv);
 378
 379                         out += blocks * AES_BLOCK_SIZE;
 380                         in += blocks * AES_BLOCK_SIZE;
 381                         nbytes -= blocks * AES_BLOCK_SIZE;
 382                 }
 383
 384                 if (walk.nbytes == walk.total && nbytes > 0)
 385                         goto xts_tail;
 386
 387                 kernel_neon_end();
 388                 err = skcipher_walk_done(&walk, nbytes);
 389         }
 390
 391         if (err || likely(!tail))
 392                 return err;
 393
 394         /* handle ciphertext stealing */
 395         dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
 396         if (req->dst != req->src)
 397                 dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
 398
 399         skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
 400                                    req->iv);
 401
 402         err = skcipher_walk_virt(&walk, req, false);
 403         if (err)
 404                 return err;
 405
 406         out = walk.dst.virt.addr;
 407         in = walk.src.virt.addr;
 408         nbytes = walk.nbytes;
 409
 410         kernel_neon_begin();
 411 xts_tail:
 412         if (encrypt)
 413                 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, ctx->key.rounds,
 414                                      nbytes, ctx->twkey, walk.iv, first ?: 2);
 415         else
 416                 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, ctx->key.rounds,
 417                                      nbytes, ctx->twkey, walk.iv, first ?: 2);
 418         kernel_neon_end();
 419
 420         return skcipher_walk_done(&walk, 0);
 421 }
 422
 423 static int xts_encrypt(struct skcipher_request *req)
 424 {
 425         return __xts_crypt(req, true, aesbs_xts_encrypt);
 426 }
 427
 428 static int xts_decrypt(struct skcipher_request *req)
 429 {
 430         return __xts_crypt(req, false, aesbs_xts_decrypt);
 431 }
 432
 433 static struct skcipher_alg aes_algs[] = { {
 434         .base.cra_name          = "__ecb(aes)",
 435         .base.cra_driver_name   = "__ecb-aes-neonbs",
 436         .base.cra_priority      = 250,
 437         .base.cra_blocksize     = AES_BLOCK_SIZE,
 438         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 439         .base.cra_module        = THIS_MODULE,
 440         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 441
 442         .min_keysize            = AES_MIN_KEY_SIZE,
 443         .max_keysize            = AES_MAX_KEY_SIZE,
 444         .walksize               = 8 * AES_BLOCK_SIZE,
 445         .setkey                 = aesbs_setkey,
 446         .encrypt                = ecb_encrypt,
 447         .decrypt                = ecb_decrypt,
 448 }, {
 449         .base.cra_name          = "__cbc(aes)",
 450         .base.cra_driver_name   = "__cbc-aes-neonbs",
 451         .base.cra_priority      = 250,
 452         .base.cra_blocksize     = AES_BLOCK_SIZE,
 453         .base.cra_ctxsize       = sizeof(struct aesbs_cbc_ctx),
 454         .base.cra_module        = THIS_MODULE,
 455         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 456
 457         .min_keysize            = AES_MIN_KEY_SIZE,
 458         .max_keysize            = AES_MAX_KEY_SIZE,
 459         .walksize               = 8 * AES_BLOCK_SIZE,
 460         .ivsize                 = AES_BLOCK_SIZE,
 461         .setkey                 = aesbs_cbc_setkey,
 462         .encrypt                = cbc_encrypt,
 463         .decrypt                = cbc_decrypt,
 464 }, {
 465         .base.cra_name          = "__ctr(aes)",
 466         .base.cra_driver_name   = "__ctr-aes-neonbs",
 467         .base.cra_priority      = 250,
 468         .base.cra_blocksize     = 1,
 469         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 470         .base.cra_module        = THIS_MODULE,
 471         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 472
 473         .min_keysize            = AES_MIN_KEY_SIZE,
 474         .max_keysize            = AES_MAX_KEY_SIZE,
 475         .chunksize              = AES_BLOCK_SIZE,
 476         .walksize               = 8 * AES_BLOCK_SIZE,
 477         .ivsize                 = AES_BLOCK_SIZE,
 478         .setkey                 = aesbs_setkey,
 479         .encrypt                = ctr_encrypt,
 480         .decrypt                = ctr_encrypt,
 481 }, {
 482         .base.cra_name          = "ctr(aes)",
 483         .base.cra_driver_name   = "ctr-aes-neonbs",
 484         .base.cra_priority      = 250 - 1,
 485         .base.cra_blocksize     = 1,
 486         .base.cra_ctxsize       = sizeof(struct aesbs_ctr_ctx),
 487         .base.cra_module        = THIS_MODULE,
 488
 489         .min_keysize            = AES_MIN_KEY_SIZE,
 490         .max_keysize            = AES_MAX_KEY_SIZE,
 491         .chunksize              = AES_BLOCK_SIZE,
 492         .walksize               = 8 * AES_BLOCK_SIZE,
 493         .ivsize                 = AES_BLOCK_SIZE,
 494         .setkey                 = aesbs_ctr_setkey_sync,
 495         .encrypt                = ctr_encrypt_sync,
 496         .decrypt                = ctr_encrypt_sync,
 497 }, {
 498         .base.cra_name          = "__xts(aes)",
 499         .base.cra_driver_name   = "__xts-aes-neonbs",
 500         .base.cra_priority      = 250,
 501         .base.cra_blocksize     = AES_BLOCK_SIZE,
 502         .base.cra_ctxsize       = sizeof(struct aesbs_xts_ctx),
 503         .base.cra_module        = THIS_MODULE,
 504         .base.cra_flags         = CRYPTO_ALG_INTERNAL,
 505
 506         .min_keysize            = 2 * AES_MIN_KEY_SIZE,
 507         .max_keysize            = 2 * AES_MAX_KEY_SIZE,
 508         .walksize               = 8 * AES_BLOCK_SIZE,
 509         .ivsize                 = AES_BLOCK_SIZE,
 510         .setkey                 = aesbs_xts_setkey,
 511         .encrypt                = xts_encrypt,
 512         .decrypt                = xts_decrypt,
 513 } };
 514
 515 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
 516
 517 static void aes_exit(void)
 518 {
 519         int i;
 520
 521         for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
 522                 if (aes_simd_algs[i])
 523                         simd_skcipher_free(aes_simd_algs[i]);
 524
 525         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 526 }
 527
 528 static int __init aes_init(void)
 529 {
 530         struct simd_skcipher_alg *simd;
 531         const char *basename;
 532         const char *algname;
 533         const char *drvname;
 534         int err;
 535         int i;
 536
 537         if (!cpu_have_named_feature(ASIMD))
 538                 return -ENODEV;
 539
 540         err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 541         if (err)
 542                 return err;
 543
 544         for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 545                 if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
 546                         continue;
 547
 548                 algname = aes_algs[i].base.cra_name + 2;
 549                 drvname = aes_algs[i].base.cra_driver_name + 2;
 550                 basename = aes_algs[i].base.cra_driver_name;
 551                 simd = simd_skcipher_create_compat(algname, drvname, basename);
 552                 err = PTR_ERR(simd);
 553                 if (IS_ERR(simd))
 554                         goto unregister_simds;
 555
 556                 aes_simd_algs[i] = simd;
 557         }
 558         return 0;
 559
 560 unregister_simds:
 561         aes_exit();
 562         return err;
 563 }
 564
 565 module_init(aes_init);
 566 module_exit(aes_exit);