arch/arm/crypto/aesbs-glue.c

   1 /*
   2  * linux/arch/arm/crypto/aesbs-glue.c - glue code for NEON bit sliced AES
   3  *
   4  * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <asm/neon.h>
  12 #include <crypto/aes.h>
  13 #include <crypto/ablk_helper.h>
  14 #include <crypto/algapi.h>
  15 #include <linux/module.h>
  16 #include <crypto/xts.h>
  17
  18 #include "aes_glue.h"
  19
  20 #define BIT_SLICED_KEY_MAXSIZE  (128 * (AES_MAXNR - 1) + 2 * AES_BLOCK_SIZE)
  21
  22 struct BS_KEY {
  23         struct AES_KEY  rk;
  24         int             converted;
  25         u8 __aligned(8) bs[BIT_SLICED_KEY_MAXSIZE];
  26 } __aligned(8);
  27
  28 asmlinkage void bsaes_enc_key_convert(u8 out[], struct AES_KEY const *in);
  29 asmlinkage void bsaes_dec_key_convert(u8 out[], struct AES_KEY const *in);
  30
  31 asmlinkage void bsaes_cbc_encrypt(u8 const in[], u8 out[], u32 bytes,
  32                                   struct BS_KEY *key, u8 iv[]);
  33
  34 asmlinkage void bsaes_ctr32_encrypt_blocks(u8 const in[], u8 out[], u32 blocks,
  35                                            struct BS_KEY *key, u8 const iv[]);
  36
  37 asmlinkage void bsaes_xts_encrypt(u8 const in[], u8 out[], u32 bytes,
  38                                   struct BS_KEY *key, u8 tweak[]);
  39
  40 asmlinkage void bsaes_xts_decrypt(u8 const in[], u8 out[], u32 bytes,
  41                                   struct BS_KEY *key, u8 tweak[]);
  42
  43 struct aesbs_cbc_ctx {
  44         struct AES_KEY  enc;
  45         struct BS_KEY   dec;
  46 };
  47
  48 struct aesbs_ctr_ctx {
  49         struct BS_KEY   enc;
  50 };
  51
  52 struct aesbs_xts_ctx {
  53         struct BS_KEY   enc;
  54         struct BS_KEY   dec;
  55         struct AES_KEY  twkey;
  56 };
  57
  58 static int aesbs_cbc_set_key(struct crypto_tfm *tfm, const u8 *in_key,
  59                              unsigned int key_len)
  60 {
  61         struct aesbs_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
  62         int bits = key_len * 8;
  63
  64         if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc)) {
  65                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  66                 return -EINVAL;
  67         }
  68         ctx->dec.rk = ctx->enc;
  69         private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
  70         ctx->dec.converted = 0;
  71         return 0;
  72 }
  73
  74 static int aesbs_ctr_set_key(struct crypto_tfm *tfm, const u8 *in_key,
  75                              unsigned int key_len)
  76 {
  77         struct aesbs_ctr_ctx *ctx = crypto_tfm_ctx(tfm);
  78         int bits = key_len * 8;
  79
  80         if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
  81                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  82                 return -EINVAL;
  83         }
  84         ctx->enc.converted = 0;
  85         return 0;
  86 }
  87
  88 static int aesbs_xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
  89                              unsigned int key_len)
  90 {
  91         struct aesbs_xts_ctx *ctx = crypto_tfm_ctx(tfm);
  92         int bits = key_len * 4;
  93         int err;
  94
  95         err = xts_check_key(tfm, in_key, key_len);
  96         if (err)
  97                 return err;
  98
  99         if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
 100                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 101                 return -EINVAL;
 102         }
 103         ctx->dec.rk = ctx->enc.rk;
 104         private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
 105         private_AES_set_encrypt_key(in_key + key_len / 2, bits, &ctx->twkey);
 106         ctx->enc.converted = ctx->dec.converted = 0;
 107         return 0;
 108 }
 109
 110 static int aesbs_cbc_encrypt(struct blkcipher_desc *desc,
 111                              struct scatterlist *dst,
 112                              struct scatterlist *src, unsigned int nbytes)
 113 {
 114         struct aesbs_cbc_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 115         struct blkcipher_walk walk;
 116         int err;
 117
 118         blkcipher_walk_init(&walk, dst, src, nbytes);
 119         err = blkcipher_walk_virt(desc, &walk);
 120
 121         while (walk.nbytes) {
 122                 u32 blocks = walk.nbytes / AES_BLOCK_SIZE;
 123                 u8 *src = walk.src.virt.addr;
 124
 125                 if (walk.dst.virt.addr == walk.src.virt.addr) {
 126                         u8 *iv = walk.iv;
 127
 128                         do {
 129                                 crypto_xor(src, iv, AES_BLOCK_SIZE);
 130                                 AES_encrypt(src, src, &ctx->enc);
 131                                 iv = src;
 132                                 src += AES_BLOCK_SIZE;
 133                         } while (--blocks);
 134                         memcpy(walk.iv, iv, AES_BLOCK_SIZE);
 135                 } else {
 136                         u8 *dst = walk.dst.virt.addr;
 137
 138                         do {
 139                                 crypto_xor(walk.iv, src, AES_BLOCK_SIZE);
 140                                 AES_encrypt(walk.iv, dst, &ctx->enc);
 141                                 memcpy(walk.iv, dst, AES_BLOCK_SIZE);
 142                                 src += AES_BLOCK_SIZE;
 143                                 dst += AES_BLOCK_SIZE;
 144                         } while (--blocks);
 145                 }
 146                 err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 147         }
 148         return err;
 149 }
 150
 151 static int aesbs_cbc_decrypt(struct blkcipher_desc *desc,
 152                              struct scatterlist *dst,
 153                              struct scatterlist *src, unsigned int nbytes)
 154 {
 155         struct aesbs_cbc_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 156         struct blkcipher_walk walk;
 157         int err;
 158
 159         blkcipher_walk_init(&walk, dst, src, nbytes);
 160         err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);
 161
 162         while ((walk.nbytes / AES_BLOCK_SIZE) >= 8) {
 163                 kernel_neon_begin();
 164                 bsaes_cbc_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
 165                                   walk.nbytes, &ctx->dec, walk.iv);
 166                 kernel_neon_end();
 167                 err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 168         }
 169         while (walk.nbytes) {
 170                 u32 blocks = walk.nbytes / AES_BLOCK_SIZE;
 171                 u8 *dst = walk.dst.virt.addr;
 172                 u8 *src = walk.src.virt.addr;
 173                 u8 bk[2][AES_BLOCK_SIZE];
 174                 u8 *iv = walk.iv;
 175
 176                 do {
 177                         if (walk.dst.virt.addr == walk.src.virt.addr)
 178                                 memcpy(bk[blocks & 1], src, AES_BLOCK_SIZE);
 179
 180                         AES_decrypt(src, dst, &ctx->dec.rk);
 181                         crypto_xor(dst, iv, AES_BLOCK_SIZE);
 182
 183                         if (walk.dst.virt.addr == walk.src.virt.addr)
 184                                 iv = bk[blocks & 1];
 185                         else
 186                                 iv = src;
 187
 188                         dst += AES_BLOCK_SIZE;
 189                         src += AES_BLOCK_SIZE;
 190                 } while (--blocks);
 191                 err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 192         }
 193         return err;
 194 }
 195
 196 static void inc_be128_ctr(__be32 ctr[], u32 addend)
 197 {
 198         int i;
 199
 200         for (i = 3; i >= 0; i--, addend = 1) {
 201                 u32 n = be32_to_cpu(ctr[i]) + addend;
 202
 203                 ctr[i] = cpu_to_be32(n);
 204                 if (n >= addend)
 205                         break;
 206         }
 207 }
 208
 209 static int aesbs_ctr_encrypt(struct blkcipher_desc *desc,
 210                              struct scatterlist *dst, struct scatterlist *src,
 211                              unsigned int nbytes)
 212 {
 213         struct aesbs_ctr_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 214         struct blkcipher_walk walk;
 215         u32 blocks;
 216         int err;
 217
 218         blkcipher_walk_init(&walk, dst, src, nbytes);
 219         err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);
 220
 221         while ((blocks = walk.nbytes / AES_BLOCK_SIZE)) {
 222                 u32 tail = walk.nbytes % AES_BLOCK_SIZE;
 223                 __be32 *ctr = (__be32 *)walk.iv;
 224                 u32 headroom = UINT_MAX - be32_to_cpu(ctr[3]);
 225
 226                 /* avoid 32 bit counter overflow in the NEON code */
 227                 if (unlikely(headroom < blocks)) {
 228                         blocks = headroom + 1;
 229                         tail = walk.nbytes - blocks * AES_BLOCK_SIZE;
 230                 }
 231                 kernel_neon_begin();
 232                 bsaes_ctr32_encrypt_blocks(walk.src.virt.addr,
 233                                            walk.dst.virt.addr, blocks,
 234                                            &ctx->enc, walk.iv);
 235                 kernel_neon_end();
 236                 inc_be128_ctr(ctr, blocks);
 237
 238                 nbytes -= blocks * AES_BLOCK_SIZE;
 239                 if (nbytes && nbytes == tail && nbytes <= AES_BLOCK_SIZE)
 240                         break;
 241
 242                 err = blkcipher_walk_done(desc, &walk, tail);
 243         }
 244         if (walk.nbytes) {
 245                 u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
 246                 u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
 247                 u8 ks[AES_BLOCK_SIZE];
 248
 249                 AES_encrypt(walk.iv, ks, &ctx->enc.rk);
 250                 if (tdst != tsrc)
 251                         memcpy(tdst, tsrc, nbytes);
 252                 crypto_xor(tdst, ks, nbytes);
 253                 err = blkcipher_walk_done(desc, &walk, 0);
 254         }
 255         return err;
 256 }
 257
 258 static int aesbs_xts_encrypt(struct blkcipher_desc *desc,
 259                              struct scatterlist *dst,
 260                              struct scatterlist *src, unsigned int nbytes)
 261 {
 262         struct aesbs_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 263         struct blkcipher_walk walk;
 264         int err;
 265
 266         blkcipher_walk_init(&walk, dst, src, nbytes);
 267         err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);
 268
 269         /* generate the initial tweak */
 270         AES_encrypt(walk.iv, walk.iv, &ctx->twkey);
 271
 272         while (walk.nbytes) {
 273                 kernel_neon_begin();
 274                 bsaes_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
 275                                   walk.nbytes, &ctx->enc, walk.iv);
 276                 kernel_neon_end();
 277                 err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 278         }
 279         return err;
 280 }
 281
 282 static int aesbs_xts_decrypt(struct blkcipher_desc *desc,
 283                              struct scatterlist *dst,
 284                              struct scatterlist *src, unsigned int nbytes)
 285 {
 286         struct aesbs_xts_ctx *ctx = crypto_blkcipher_ctx(desc->tfm);
 287         struct blkcipher_walk walk;
 288         int err;
 289
 290         blkcipher_walk_init(&walk, dst, src, nbytes);
 291         err = blkcipher_walk_virt_block(desc, &walk, 8 * AES_BLOCK_SIZE);
 292
 293         /* generate the initial tweak */
 294         AES_encrypt(walk.iv, walk.iv, &ctx->twkey);
 295
 296         while (walk.nbytes) {
 297                 kernel_neon_begin();
 298                 bsaes_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
 299                                   walk.nbytes, &ctx->dec, walk.iv);
 300                 kernel_neon_end();
 301                 err = blkcipher_walk_done(desc, &walk, walk.nbytes % AES_BLOCK_SIZE);
 302         }
 303         return err;
 304 }
 305
 306 static struct crypto_alg aesbs_algs[] = { {
 307         .cra_name               = "__cbc-aes-neonbs",
 308         .cra_driver_name        = "__driver-cbc-aes-neonbs",
 309         .cra_priority           = 0,
 310         .cra_flags              = CRYPTO_ALG_TYPE_BLKCIPHER |
 311                                   CRYPTO_ALG_INTERNAL,
 312         .cra_blocksize          = AES_BLOCK_SIZE,
 313         .cra_ctxsize            = sizeof(struct aesbs_cbc_ctx),
 314         .cra_alignmask          = 7,
 315         .cra_type               = &crypto_blkcipher_type,
 316         .cra_module             = THIS_MODULE,
 317         .cra_blkcipher = {
 318                 .min_keysize    = AES_MIN_KEY_SIZE,
 319                 .max_keysize    = AES_MAX_KEY_SIZE,
 320                 .ivsize         = AES_BLOCK_SIZE,
 321                 .setkey         = aesbs_cbc_set_key,
 322                 .encrypt        = aesbs_cbc_encrypt,
 323                 .decrypt        = aesbs_cbc_decrypt,
 324         },
 325 }, {
 326         .cra_name               = "__ctr-aes-neonbs",
 327         .cra_driver_name        = "__driver-ctr-aes-neonbs",
 328         .cra_priority           = 0,
 329         .cra_flags              = CRYPTO_ALG_TYPE_BLKCIPHER |
 330                                   CRYPTO_ALG_INTERNAL,
 331         .cra_blocksize          = 1,
 332         .cra_ctxsize            = sizeof(struct aesbs_ctr_ctx),
 333         .cra_alignmask          = 7,
 334         .cra_type               = &crypto_blkcipher_type,
 335         .cra_module             = THIS_MODULE,
 336         .cra_blkcipher = {
 337                 .min_keysize    = AES_MIN_KEY_SIZE,
 338                 .max_keysize    = AES_MAX_KEY_SIZE,
 339                 .ivsize         = AES_BLOCK_SIZE,
 340                 .setkey         = aesbs_ctr_set_key,
 341                 .encrypt        = aesbs_ctr_encrypt,
 342                 .decrypt        = aesbs_ctr_encrypt,
 343         },
 344 }, {
 345         .cra_name               = "__xts-aes-neonbs",
 346         .cra_driver_name        = "__driver-xts-aes-neonbs",
 347         .cra_priority           = 0,
 348         .cra_flags              = CRYPTO_ALG_TYPE_BLKCIPHER |
 349                                   CRYPTO_ALG_INTERNAL,
 350         .cra_blocksize          = AES_BLOCK_SIZE,
 351         .cra_ctxsize            = sizeof(struct aesbs_xts_ctx),
 352         .cra_alignmask          = 7,
 353         .cra_type               = &crypto_blkcipher_type,
 354         .cra_module             = THIS_MODULE,
 355         .cra_blkcipher = {
 356                 .min_keysize    = 2 * AES_MIN_KEY_SIZE,
 357                 .max_keysize    = 2 * AES_MAX_KEY_SIZE,
 358                 .ivsize         = AES_BLOCK_SIZE,
 359                 .setkey         = aesbs_xts_set_key,
 360                 .encrypt        = aesbs_xts_encrypt,
 361                 .decrypt        = aesbs_xts_decrypt,
 362         },
 363 }, {
 364         .cra_name               = "cbc(aes)",
 365         .cra_driver_name        = "cbc-aes-neonbs",
 366         .cra_priority           = 300,
 367         .cra_flags              = CRYPTO_ALG_TYPE_ABLKCIPHER|CRYPTO_ALG_ASYNC,
 368         .cra_blocksize          = AES_BLOCK_SIZE,
 369         .cra_ctxsize            = sizeof(struct async_helper_ctx),
 370         .cra_alignmask          = 7,
 371         .cra_type               = &crypto_ablkcipher_type,
 372         .cra_module             = THIS_MODULE,
 373         .cra_init               = ablk_init,
 374         .cra_exit               = ablk_exit,
 375         .cra_ablkcipher = {
 376                 .min_keysize    = AES_MIN_KEY_SIZE,
 377                 .max_keysize    = AES_MAX_KEY_SIZE,
 378                 .ivsize         = AES_BLOCK_SIZE,
 379                 .setkey         = ablk_set_key,
 380                 .encrypt        = __ablk_encrypt,
 381                 .decrypt        = ablk_decrypt,
 382         }
 383 }, {
 384         .cra_name               = "ctr(aes)",
 385         .cra_driver_name        = "ctr-aes-neonbs",
 386         .cra_priority           = 300,
 387         .cra_flags              = CRYPTO_ALG_TYPE_ABLKCIPHER|CRYPTO_ALG_ASYNC,
 388         .cra_blocksize          = 1,
 389         .cra_ctxsize            = sizeof(struct async_helper_ctx),
 390         .cra_alignmask          = 7,
 391         .cra_type               = &crypto_ablkcipher_type,
 392         .cra_module             = THIS_MODULE,
 393         .cra_init               = ablk_init,
 394         .cra_exit               = ablk_exit,
 395         .cra_ablkcipher = {
 396                 .min_keysize    = AES_MIN_KEY_SIZE,
 397                 .max_keysize    = AES_MAX_KEY_SIZE,
 398                 .ivsize         = AES_BLOCK_SIZE,
 399                 .setkey         = ablk_set_key,
 400                 .encrypt        = ablk_encrypt,
 401                 .decrypt        = ablk_decrypt,
 402         }
 403 }, {
 404         .cra_name               = "xts(aes)",
 405         .cra_driver_name        = "xts-aes-neonbs",
 406         .cra_priority           = 300,
 407         .cra_flags              = CRYPTO_ALG_TYPE_ABLKCIPHER|CRYPTO_ALG_ASYNC,
 408         .cra_blocksize          = AES_BLOCK_SIZE,
 409         .cra_ctxsize            = sizeof(struct async_helper_ctx),
 410         .cra_alignmask          = 7,
 411         .cra_type               = &crypto_ablkcipher_type,
 412         .cra_module             = THIS_MODULE,
 413         .cra_init               = ablk_init,
 414         .cra_exit               = ablk_exit,
 415         .cra_ablkcipher = {
 416                 .min_keysize    = 2 * AES_MIN_KEY_SIZE,
 417                 .max_keysize    = 2 * AES_MAX_KEY_SIZE,
 418                 .ivsize         = AES_BLOCK_SIZE,
 419                 .setkey         = ablk_set_key,
 420                 .encrypt        = ablk_encrypt,
 421                 .decrypt        = ablk_decrypt,
 422         }
 423 } };
 424
 425 static int __init aesbs_mod_init(void)
 426 {
 427         if (!cpu_has_neon())
 428                 return -ENODEV;
 429
 430         return crypto_register_algs(aesbs_algs, ARRAY_SIZE(aesbs_algs));
 431 }
 432
 433 static void __exit aesbs_mod_exit(void)
 434 {
 435         crypto_unregister_algs(aesbs_algs, ARRAY_SIZE(aesbs_algs));
 436 }
 437
 438 module_init(aesbs_mod_init);
 439 module_exit(aesbs_mod_exit);
 440
 441 MODULE_DESCRIPTION("Bit sliced AES in CBC/CTR/XTS modes using NEON");
 442 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 443 MODULE_LICENSE("GPL");