arch/arm/crypto/aes-ce-glue.c

   1 /*
   2  * aes-ce-glue.c - wrapper code for ARMv8 AES
   3  *
   4  * Copyright (C) 2015 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/hwcap.h>
  12 #include <asm/neon.h>
  13 #include <asm/hwcap.h>
  14 #include <crypto/aes.h>
  15 #include <crypto/internal/simd.h>
  16 #include <crypto/internal/skcipher.h>
  17 #include <linux/cpufeature.h>
  18 #include <linux/module.h>
  19 #include <crypto/xts.h>
  20
  21 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
  22 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  23 MODULE_LICENSE("GPL v2");
  24
  25 /* defined in aes-ce-core.S */
  26 asmlinkage u32 ce_aes_sub(u32 input);
  27 asmlinkage void ce_aes_invert(void *dst, void *src);
  28
  29 asmlinkage void ce_aes_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
  30                                    int rounds, int blocks);
  31 asmlinkage void ce_aes_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
  32                                    int rounds, int blocks);
  33
  34 asmlinkage void ce_aes_cbc_encrypt(u8 out[], u8 const in[], u8 const rk[],
  35                                    int rounds, int blocks, u8 iv[]);
  36 asmlinkage void ce_aes_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
  37                                    int rounds, int blocks, u8 iv[]);
  38
  39 asmlinkage void ce_aes_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
  40                                    int rounds, int blocks, u8 ctr[]);
  41
  42 asmlinkage void ce_aes_xts_encrypt(u8 out[], u8 const in[], u8 const rk1[],
  43                                    int rounds, int blocks, u8 iv[],
  44                                    u8 const rk2[], int first);
  45 asmlinkage void ce_aes_xts_decrypt(u8 out[], u8 const in[], u8 const rk1[],
  46                                    int rounds, int blocks, u8 iv[],
  47                                    u8 const rk2[], int first);
  48
  49 struct aes_block {
  50         u8 b[AES_BLOCK_SIZE];
  51 };
  52
  53 static int num_rounds(struct crypto_aes_ctx *ctx)
  54 {
  55         /*
  56          * # of rounds specified by AES:
  57          * 128 bit key          10 rounds
  58          * 192 bit key          12 rounds
  59          * 256 bit key          14 rounds
  60          * => n byte key        => 6 + (n/4) rounds
  61          */
  62         return 6 + ctx->key_length / 4;
  63 }
  64
  65 static int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
  66                             unsigned int key_len)
  67 {
  68         /*
  69          * The AES key schedule round constants
  70          */
  71         static u8 const rcon[] = {
  72                 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
  73         };
  74
  75         u32 kwords = key_len / sizeof(u32);
  76         struct aes_block *key_enc, *key_dec;
  77         int i, j;
  78
  79         if (key_len != AES_KEYSIZE_128 &&
  80             key_len != AES_KEYSIZE_192 &&
  81             key_len != AES_KEYSIZE_256)
  82                 return -EINVAL;
  83
  84         memcpy(ctx->key_enc, in_key, key_len);
  85         ctx->key_length = key_len;
  86
  87         kernel_neon_begin();
  88         for (i = 0; i < sizeof(rcon); i++) {
  89                 u32 *rki = ctx->key_enc + (i * kwords);
  90                 u32 *rko = rki + kwords;
  91
  92 #ifndef CONFIG_CPU_BIG_ENDIAN
  93                 rko[0] = ror32(ce_aes_sub(rki[kwords - 1]), 8);
  94                 rko[0] = rko[0] ^ rki[0] ^ rcon[i];
  95 #else
  96                 rko[0] = rol32(ce_aes_sub(rki[kwords - 1]), 8);
  97                 rko[0] = rko[0] ^ rki[0] ^ (rcon[i] << 24);
  98 #endif
  99                 rko[1] = rko[0] ^ rki[1];
 100                 rko[2] = rko[1] ^ rki[2];
 101                 rko[3] = rko[2] ^ rki[3];
 102
 103                 if (key_len == AES_KEYSIZE_192) {
 104                         if (i >= 7)
 105                                 break;
 106                         rko[4] = rko[3] ^ rki[4];
 107                         rko[5] = rko[4] ^ rki[5];
 108                 } else if (key_len == AES_KEYSIZE_256) {
 109                         if (i >= 6)
 110                                 break;
 111                         rko[4] = ce_aes_sub(rko[3]) ^ rki[4];
 112                         rko[5] = rko[4] ^ rki[5];
 113                         rko[6] = rko[5] ^ rki[6];
 114                         rko[7] = rko[6] ^ rki[7];
 115                 }
 116         }
 117
 118         /*
 119          * Generate the decryption keys for the Equivalent Inverse Cipher.
 120          * This involves reversing the order of the round keys, and applying
 121          * the Inverse Mix Columns transformation on all but the first and
 122          * the last one.
 123          */
 124         key_enc = (struct aes_block *)ctx->key_enc;
 125         key_dec = (struct aes_block *)ctx->key_dec;
 126         j = num_rounds(ctx);
 127
 128         key_dec[0] = key_enc[j];
 129         for (i = 1, j--; j > 0; i++, j--)
 130                 ce_aes_invert(key_dec + i, key_enc + j);
 131         key_dec[i] = key_enc[0];
 132
 133         kernel_neon_end();
 134         return 0;
 135 }
 136
 137 static int ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 138                          unsigned int key_len)
 139 {
 140         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 141         int ret;
 142
 143         ret = ce_aes_expandkey(ctx, in_key, key_len);
 144         if (!ret)
 145                 return 0;
 146
 147         crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 148         return -EINVAL;
 149 }
 150
 151 struct crypto_aes_xts_ctx {
 152         struct crypto_aes_ctx key1;
 153         struct crypto_aes_ctx __aligned(8) key2;
 154 };
 155
 156 static int xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
 157                        unsigned int key_len)
 158 {
 159         struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 160         int ret;
 161
 162         ret = xts_verify_key(tfm, in_key, key_len);
 163         if (ret)
 164                 return ret;
 165
 166         ret = ce_aes_expandkey(&ctx->key1, in_key, key_len / 2);
 167         if (!ret)
 168                 ret = ce_aes_expandkey(&ctx->key2, &in_key[key_len / 2],
 169                                        key_len / 2);
 170         if (!ret)
 171                 return 0;
 172
 173         crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 174         return -EINVAL;
 175 }
 176
 177 static int ecb_encrypt(struct skcipher_request *req)
 178 {
 179         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 180         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 181         struct skcipher_walk walk;
 182         unsigned int blocks;
 183         int err;
 184
 185         err = skcipher_walk_virt(&walk, req, true);
 186
 187         kernel_neon_begin();
 188         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 189                 ce_aes_ecb_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 190                                    (u8 *)ctx->key_enc, num_rounds(ctx), blocks);
 191                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 192         }
 193         kernel_neon_end();
 194         return err;
 195 }
 196
 197 static int ecb_decrypt(struct skcipher_request *req)
 198 {
 199         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 200         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 201         struct skcipher_walk walk;
 202         unsigned int blocks;
 203         int err;
 204
 205         err = skcipher_walk_virt(&walk, req, true);
 206
 207         kernel_neon_begin();
 208         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 209                 ce_aes_ecb_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 210                                    (u8 *)ctx->key_dec, num_rounds(ctx), blocks);
 211                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 212         }
 213         kernel_neon_end();
 214         return err;
 215 }
 216
 217 static int cbc_encrypt(struct skcipher_request *req)
 218 {
 219         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 220         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 221         struct skcipher_walk walk;
 222         unsigned int blocks;
 223         int err;
 224
 225         err = skcipher_walk_virt(&walk, req, true);
 226
 227         kernel_neon_begin();
 228         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 229                 ce_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 230                                    (u8 *)ctx->key_enc, num_rounds(ctx), blocks,
 231                                    walk.iv);
 232                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 233         }
 234         kernel_neon_end();
 235         return err;
 236 }
 237
 238 static int cbc_decrypt(struct skcipher_request *req)
 239 {
 240         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 241         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 242         struct skcipher_walk walk;
 243         unsigned int blocks;
 244         int err;
 245
 246         err = skcipher_walk_virt(&walk, req, true);
 247
 248         kernel_neon_begin();
 249         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 250                 ce_aes_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 251                                    (u8 *)ctx->key_dec, num_rounds(ctx), blocks,
 252                                    walk.iv);
 253                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 254         }
 255         kernel_neon_end();
 256         return err;
 257 }
 258
 259 static int ctr_encrypt(struct skcipher_request *req)
 260 {
 261         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 262         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 263         struct skcipher_walk walk;
 264         int err, blocks;
 265
 266         err = skcipher_walk_virt(&walk, req, true);
 267
 268         kernel_neon_begin();
 269         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 270                 ce_aes_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 271                                    (u8 *)ctx->key_enc, num_rounds(ctx), blocks,
 272                                    walk.iv);
 273                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 274         }
 275         if (walk.nbytes) {
 276                 u8 __aligned(8) tail[AES_BLOCK_SIZE];
 277                 unsigned int nbytes = walk.nbytes;
 278                 u8 *tdst = walk.dst.virt.addr;
 279                 u8 *tsrc = walk.src.virt.addr;
 280
 281                 /*
 282                  * Tell aes_ctr_encrypt() to process a tail block.
 283                  */
 284                 blocks = -1;
 285
 286                 ce_aes_ctr_encrypt(tail, NULL, (u8 *)ctx->key_enc,
 287                                    num_rounds(ctx), blocks, walk.iv);
 288                 crypto_xor_cpy(tdst, tsrc, tail, nbytes);
 289                 err = skcipher_walk_done(&walk, 0);
 290         }
 291         kernel_neon_end();
 292
 293         return err;
 294 }
 295
 296 static int xts_encrypt(struct skcipher_request *req)
 297 {
 298         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 299         struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 300         int err, first, rounds = num_rounds(&ctx->key1);
 301         struct skcipher_walk walk;
 302         unsigned int blocks;
 303
 304         err = skcipher_walk_virt(&walk, req, true);
 305
 306         kernel_neon_begin();
 307         for (first = 1; (blocks = (walk.nbytes / AES_BLOCK_SIZE)); first = 0) {
 308                 ce_aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 309                                    (u8 *)ctx->key1.key_enc, rounds, blocks,
 310                                    walk.iv, (u8 *)ctx->key2.key_enc, first);
 311                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 312         }
 313         kernel_neon_end();
 314
 315         return err;
 316 }
 317
 318 static int xts_decrypt(struct skcipher_request *req)
 319 {
 320         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 321         struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 322         int err, first, rounds = num_rounds(&ctx->key1);
 323         struct skcipher_walk walk;
 324         unsigned int blocks;
 325
 326         err = skcipher_walk_virt(&walk, req, true);
 327
 328         kernel_neon_begin();
 329         for (first = 1; (blocks = (walk.nbytes / AES_BLOCK_SIZE)); first = 0) {
 330                 ce_aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 331                                    (u8 *)ctx->key1.key_dec, rounds, blocks,
 332                                    walk.iv, (u8 *)ctx->key2.key_enc, first);
 333                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 334         }
 335         kernel_neon_end();
 336
 337         return err;
 338 }
 339
 340 static struct skcipher_alg aes_algs[] = { {
 341         .base = {
 342                 .cra_name               = "__ecb(aes)",
 343                 .cra_driver_name        = "__ecb-aes-ce",
 344                 .cra_priority           = 300,
 345                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 346                 .cra_blocksize          = AES_BLOCK_SIZE,
 347                 .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 348                 .cra_module             = THIS_MODULE,
 349         },
 350         .min_keysize    = AES_MIN_KEY_SIZE,
 351         .max_keysize    = AES_MAX_KEY_SIZE,
 352         .setkey         = ce_aes_setkey,
 353         .encrypt        = ecb_encrypt,
 354         .decrypt        = ecb_decrypt,
 355 }, {
 356         .base = {
 357                 .cra_name               = "__cbc(aes)",
 358                 .cra_driver_name        = "__cbc-aes-ce",
 359                 .cra_priority           = 300,
 360                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 361                 .cra_blocksize          = AES_BLOCK_SIZE,
 362                 .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 363                 .cra_module             = THIS_MODULE,
 364         },
 365         .min_keysize    = AES_MIN_KEY_SIZE,
 366         .max_keysize    = AES_MAX_KEY_SIZE,
 367         .ivsize         = AES_BLOCK_SIZE,
 368         .setkey         = ce_aes_setkey,
 369         .encrypt        = cbc_encrypt,
 370         .decrypt        = cbc_decrypt,
 371 }, {
 372         .base = {
 373                 .cra_name               = "__ctr(aes)",
 374                 .cra_driver_name        = "__ctr-aes-ce",
 375                 .cra_priority           = 300,
 376                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 377                 .cra_blocksize          = 1,
 378                 .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 379                 .cra_module             = THIS_MODULE,
 380         },
 381         .min_keysize    = AES_MIN_KEY_SIZE,
 382         .max_keysize    = AES_MAX_KEY_SIZE,
 383         .ivsize         = AES_BLOCK_SIZE,
 384         .chunksize      = AES_BLOCK_SIZE,
 385         .setkey         = ce_aes_setkey,
 386         .encrypt        = ctr_encrypt,
 387         .decrypt        = ctr_encrypt,
 388 }, {
 389         .base = {
 390                 .cra_name               = "__xts(aes)",
 391                 .cra_driver_name        = "__xts-aes-ce",
 392                 .cra_priority           = 300,
 393                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 394                 .cra_blocksize          = AES_BLOCK_SIZE,
 395                 .cra_ctxsize            = sizeof(struct crypto_aes_xts_ctx),
 396                 .cra_module             = THIS_MODULE,
 397         },
 398         .min_keysize    = 2 * AES_MIN_KEY_SIZE,
 399         .max_keysize    = 2 * AES_MAX_KEY_SIZE,
 400         .ivsize         = AES_BLOCK_SIZE,
 401         .setkey         = xts_set_key,
 402         .encrypt        = xts_encrypt,
 403         .decrypt        = xts_decrypt,
 404 } };
 405
 406 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
 407
 408 static void aes_exit(void)
 409 {
 410         int i;
 411
 412         for (i = 0; i < ARRAY_SIZE(aes_simd_algs) && aes_simd_algs[i]; i++)
 413                 simd_skcipher_free(aes_simd_algs[i]);
 414
 415         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 416 }
 417
 418 static int __init aes_init(void)
 419 {
 420         struct simd_skcipher_alg *simd;
 421         const char *basename;
 422         const char *algname;
 423         const char *drvname;
 424         int err;
 425         int i;
 426
 427         err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 428         if (err)
 429                 return err;
 430
 431         for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 432                 algname = aes_algs[i].base.cra_name + 2;
 433                 drvname = aes_algs[i].base.cra_driver_name + 2;
 434                 basename = aes_algs[i].base.cra_driver_name;
 435                 simd = simd_skcipher_create_compat(algname, drvname, basename);
 436                 err = PTR_ERR(simd);
 437                 if (IS_ERR(simd))
 438                         goto unregister_simds;
 439
 440                 aes_simd_algs[i] = simd;
 441         }
 442
 443         return 0;
 444
 445 unregister_simds:
 446         aes_exit();
 447         return err;
 448 }
 449
 450 module_cpu_feature_match(AES, aes_init);
 451 module_exit(aes_exit);