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_xts_ctx {
  67         struct aesbs_ctx        key;
  68         u32                     twkey[AES_MAX_KEYLENGTH_U32];
  69         struct crypto_aes_ctx   cts;
  70 };
  71
  72 static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
  73                         unsigned int key_len)
  74 {
  75         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  76         struct crypto_aes_ctx rk;
  77         int err;
  78
  79         err = aes_expandkey(&rk, in_key, key_len);
  80         if (err)
  81                 return err;
  82
  83         ctx->rounds = 6 + key_len / 4;
  84
  85         kernel_neon_begin();
  86         aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
  87         kernel_neon_end();
  88
  89         return 0;
  90 }
  91
  92 static int __ecb_crypt(struct skcipher_request *req,
  93                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
  94                                   int rounds, int blocks))
  95 {
  96         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  97         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
  98         struct skcipher_walk walk;
  99         int err;
 100
 101         err = skcipher_walk_virt(&walk, req, false);
 102
 103         while (walk.nbytes >= AES_BLOCK_SIZE) {
 104                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 105
 106                 if (walk.nbytes < walk.total)
 107                         blocks = round_down(blocks,
 108                                             walk.stride / AES_BLOCK_SIZE);
 109
 110                 kernel_neon_begin();
 111                 fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
 112                    ctx->rounds, blocks);
 113                 kernel_neon_end();
 114                 err = skcipher_walk_done(&walk,
 115                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 116         }
 117
 118         return err;
 119 }
 120
 121 static int ecb_encrypt(struct skcipher_request *req)
 122 {
 123         return __ecb_crypt(req, aesbs_ecb_encrypt);
 124 }
 125
 126 static int ecb_decrypt(struct skcipher_request *req)
 127 {
 128         return __ecb_crypt(req, aesbs_ecb_decrypt);
 129 }
 130
 131 static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 132                             unsigned int key_len)
 133 {
 134         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 135         struct crypto_aes_ctx rk;
 136         int err;
 137
 138         err = aes_expandkey(&rk, in_key, key_len);
 139         if (err)
 140                 return err;
 141
 142         ctx->key.rounds = 6 + key_len / 4;
 143
 144         memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));
 145
 146         kernel_neon_begin();
 147         aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
 148         kernel_neon_end();
 149         memzero_explicit(&rk, sizeof(rk));
 150
 151         return 0;
 152 }
 153
 154 static int cbc_encrypt(struct skcipher_request *req)
 155 {
 156         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 157         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 158         struct skcipher_walk walk;
 159         int err;
 160
 161         err = skcipher_walk_virt(&walk, req, false);
 162
 163         while (walk.nbytes >= AES_BLOCK_SIZE) {
 164                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 165
 166                 /* fall back to the non-bitsliced NEON implementation */
 167                 kernel_neon_begin();
 168                 neon_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 169                                      ctx->enc, ctx->key.rounds, blocks,
 170                                      walk.iv);
 171                 kernel_neon_end();
 172                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 173         }
 174         return err;
 175 }
 176
 177 static int cbc_decrypt(struct skcipher_request *req)
 178 {
 179         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 180         struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
 181         struct skcipher_walk walk;
 182         int err;
 183
 184         err = skcipher_walk_virt(&walk, req, false);
 185
 186         while (walk.nbytes >= AES_BLOCK_SIZE) {
 187                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 188
 189                 if (walk.nbytes < walk.total)
 190                         blocks = round_down(blocks,
 191                                             walk.stride / AES_BLOCK_SIZE);
 192
 193                 kernel_neon_begin();
 194                 aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 195                                   ctx->key.rk, ctx->key.rounds, blocks,
 196                                   walk.iv);
 197                 kernel_neon_end();
 198                 err = skcipher_walk_done(&walk,
 199                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 200         }
 201
 202         return err;
 203 }
 204
 205 static int ctr_encrypt(struct skcipher_request *req)
 206 {
 207         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 208         struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
 209         struct skcipher_walk walk;
 210         u8 buf[AES_BLOCK_SIZE];
 211         int err;
 212
 213         err = skcipher_walk_virt(&walk, req, false);
 214
 215         while (walk.nbytes > 0) {
 216                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 217                 u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;
 218
 219                 if (walk.nbytes < walk.total) {
 220                         blocks = round_down(blocks,
 221                                             walk.stride / AES_BLOCK_SIZE);
 222                         final = NULL;
 223                 }
 224
 225                 kernel_neon_begin();
 226                 aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 227                                   ctx->rk, ctx->rounds, blocks, walk.iv, final);
 228                 kernel_neon_end();
 229
 230                 if (final) {
 231                         u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 232                         u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 233
 234                         crypto_xor_cpy(dst, src, final,
 235                                        walk.total % AES_BLOCK_SIZE);
 236
 237                         err = skcipher_walk_done(&walk, 0);
 238                         break;
 239                 }
 240                 err = skcipher_walk_done(&walk,
 241                                          walk.nbytes - blocks * AES_BLOCK_SIZE);
 242         }
 243         return err;
 244 }
 245
 246 static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 247                             unsigned int key_len)
 248 {
 249         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 250         struct crypto_aes_ctx rk;
 251         int err;
 252
 253         err = xts_verify_key(tfm, in_key, key_len);
 254         if (err)
 255                 return err;
 256
 257         key_len /= 2;
 258         err = aes_expandkey(&ctx->cts, in_key, key_len);
 259         if (err)
 260                 return err;
 261
 262         err = aes_expandkey(&rk, in_key + key_len, key_len);
 263         if (err)
 264                 return err;
 265
 266         memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));
 267
 268         return aesbs_setkey(tfm, in_key, key_len);
 269 }
 270
 271 static int __xts_crypt(struct skcipher_request *req, bool encrypt,
 272                        void (*fn)(u8 out[], u8 const in[], u8 const rk[],
 273                                   int rounds, int blocks, u8 iv[]))
 274 {
 275         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 276         struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 277         int tail = req->cryptlen % (8 * AES_BLOCK_SIZE);
 278         struct scatterlist sg_src[2], sg_dst[2];
 279         struct skcipher_request subreq;
 280         struct scatterlist *src, *dst;
 281         struct skcipher_walk walk;
 282         int nbytes, err;
 283         int first = 1;
 284         u8 *out, *in;
 285
 286         if (req->cryptlen < AES_BLOCK_SIZE)
 287                 return -EINVAL;
 288
 289         /* ensure that the cts tail is covered by a single step */
 290         if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) {
 291                 int xts_blocks = DIV_ROUND_UP(req->cryptlen,
 292                                               AES_BLOCK_SIZE) - 2;
 293
 294                 skcipher_request_set_tfm(&subreq, tfm);
 295                 skcipher_request_set_callback(&subreq,
 296                                               skcipher_request_flags(req),
 297                                               NULL, NULL);
 298                 skcipher_request_set_crypt(&subreq, req->src, req->dst,
 299                                            xts_blocks * AES_BLOCK_SIZE,
 300                                            req->iv);
 301                 req = &subreq;
 302         } else {
 303                 tail = 0;
 304         }
 305
 306         err = skcipher_walk_virt(&walk, req, false);
 307         if (err)
 308                 return err;
 309
 310         while (walk.nbytes >= AES_BLOCK_SIZE) {
 311                 unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
 312
 313                 if (walk.nbytes < walk.total || walk.nbytes % AES_BLOCK_SIZE)
 314                         blocks = round_down(blocks,
 315                                             walk.stride / AES_BLOCK_SIZE);
 316
 317                 out = walk.dst.virt.addr;
 318                 in = walk.src.virt.addr;
 319                 nbytes = walk.nbytes;
 320
 321                 kernel_neon_begin();
 322                 if (likely(blocks > 6)) { /* plain NEON is faster otherwise */
 323                         if (first)
 324                                 neon_aes_ecb_encrypt(walk.iv, walk.iv,
 325                                                      ctx->twkey,
 326                                                      ctx->key.rounds, 1);
 327                         first = 0;
 328
 329                         fn(out, in, ctx->key.rk, ctx->key.rounds, blocks,
 330                            walk.iv);
 331
 332                         out += blocks * AES_BLOCK_SIZE;
 333                         in += blocks * AES_BLOCK_SIZE;
 334                         nbytes -= blocks * AES_BLOCK_SIZE;
 335                 }
 336
 337                 if (walk.nbytes == walk.total && nbytes > 0)
 338                         goto xts_tail;
 339
 340                 kernel_neon_end();
 341                 err = skcipher_walk_done(&walk, nbytes);
 342         }
 343
 344         if (err || likely(!tail))
 345                 return err;
 346
 347         /* handle ciphertext stealing */
 348         dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
 349         if (req->dst != req->src)
 350                 dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
 351
 352         skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
 353                                    req->iv);
 354
 355         err = skcipher_walk_virt(&walk, req, false);
 356         if (err)
 357                 return err;
 358
 359         out = walk.dst.virt.addr;
 360         in = walk.src.virt.addr;
 361         nbytes = walk.nbytes;
 362
 363         kernel_neon_begin();
 364 xts_tail:
 365         if (encrypt)
 366                 neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, ctx->key.rounds,
 367                                      nbytes, ctx->twkey, walk.iv, first ?: 2);
 368         else
 369                 neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, ctx->key.rounds,
 370                                      nbytes, ctx->twkey, walk.iv, first ?: 2);
 371         kernel_neon_end();
 372
 373         return skcipher_walk_done(&walk, 0);
 374 }
 375
 376 static int xts_encrypt(struct skcipher_request *req)
 377 {
 378         return __xts_crypt(req, true, aesbs_xts_encrypt);
 379 }
 380
 381 static int xts_decrypt(struct skcipher_request *req)
 382 {
 383         return __xts_crypt(req, false, aesbs_xts_decrypt);
 384 }
 385
 386 static struct skcipher_alg aes_algs[] = { {
 387         .base.cra_name          = "ecb(aes)",
 388         .base.cra_driver_name   = "ecb-aes-neonbs",
 389         .base.cra_priority      = 250,
 390         .base.cra_blocksize     = AES_BLOCK_SIZE,
 391         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 392         .base.cra_module        = THIS_MODULE,
 393
 394         .min_keysize            = AES_MIN_KEY_SIZE,
 395         .max_keysize            = AES_MAX_KEY_SIZE,
 396         .walksize               = 8 * AES_BLOCK_SIZE,
 397         .setkey                 = aesbs_setkey,
 398         .encrypt                = ecb_encrypt,
 399         .decrypt                = ecb_decrypt,
 400 }, {
 401         .base.cra_name          = "cbc(aes)",
 402         .base.cra_driver_name   = "cbc-aes-neonbs",
 403         .base.cra_priority      = 250,
 404         .base.cra_blocksize     = AES_BLOCK_SIZE,
 405         .base.cra_ctxsize       = sizeof(struct aesbs_cbc_ctx),
 406         .base.cra_module        = THIS_MODULE,
 407
 408         .min_keysize            = AES_MIN_KEY_SIZE,
 409         .max_keysize            = AES_MAX_KEY_SIZE,
 410         .walksize               = 8 * AES_BLOCK_SIZE,
 411         .ivsize                 = AES_BLOCK_SIZE,
 412         .setkey                 = aesbs_cbc_setkey,
 413         .encrypt                = cbc_encrypt,
 414         .decrypt                = cbc_decrypt,
 415 }, {
 416         .base.cra_name          = "ctr(aes)",
 417         .base.cra_driver_name   = "ctr-aes-neonbs",
 418         .base.cra_priority      = 250,
 419         .base.cra_blocksize     = 1,
 420         .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
 421         .base.cra_module        = THIS_MODULE,
 422
 423         .min_keysize            = AES_MIN_KEY_SIZE,
 424         .max_keysize            = AES_MAX_KEY_SIZE,
 425         .chunksize              = AES_BLOCK_SIZE,
 426         .walksize               = 8 * AES_BLOCK_SIZE,
 427         .ivsize                 = AES_BLOCK_SIZE,
 428         .setkey                 = aesbs_setkey,
 429         .encrypt                = ctr_encrypt,
 430         .decrypt                = ctr_encrypt,
 431 }, {
 432         .base.cra_name          = "xts(aes)",
 433         .base.cra_driver_name   = "xts-aes-neonbs",
 434         .base.cra_priority      = 250,
 435         .base.cra_blocksize     = AES_BLOCK_SIZE,
 436         .base.cra_ctxsize       = sizeof(struct aesbs_xts_ctx),
 437         .base.cra_module        = THIS_MODULE,
 438
 439         .min_keysize            = 2 * AES_MIN_KEY_SIZE,
 440         .max_keysize            = 2 * AES_MAX_KEY_SIZE,
 441         .walksize               = 8 * AES_BLOCK_SIZE,
 442         .ivsize                 = AES_BLOCK_SIZE,
 443         .setkey                 = aesbs_xts_setkey,
 444         .encrypt                = xts_encrypt,
 445         .decrypt                = xts_decrypt,
 446 } };
 447
 448 static void aes_exit(void)
 449 {
 450         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 451 }
 452
 453 static int __init aes_init(void)
 454 {
 455         if (!cpu_have_named_feature(ASIMD))
 456                 return -ENODEV;
 457
 458         return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 459 }
 460
 461 module_init(aes_init);
 462 module_exit(aes_exit);