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/module.h>
  18 #include <crypto/xts.h>
  19
  20 MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
  21 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
  22 MODULE_LICENSE("GPL v2");
  23
  24 /* defined in aes-ce-core.S */
  25 asmlinkage u32 ce_aes_sub(u32 input);
  26 asmlinkage void ce_aes_invert(void *dst, void *src);
  27
  28 asmlinkage void ce_aes_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
  29                                    int rounds, int blocks);
  30 asmlinkage void ce_aes_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
  31                                    int rounds, int blocks);
  32
  33 asmlinkage void ce_aes_cbc_encrypt(u8 out[], u8 const in[], u8 const rk[],
  34                                    int rounds, int blocks, u8 iv[]);
  35 asmlinkage void ce_aes_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
  36                                    int rounds, int blocks, u8 iv[]);
  37
  38 asmlinkage void ce_aes_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
  39                                    int rounds, int blocks, u8 ctr[]);
  40
  41 asmlinkage void ce_aes_xts_encrypt(u8 out[], u8 const in[], u8 const rk1[],
  42                                    int rounds, int blocks, u8 iv[],
  43                                    u8 const rk2[], int first);
  44 asmlinkage void ce_aes_xts_decrypt(u8 out[], u8 const in[], u8 const rk1[],
  45                                    int rounds, int blocks, u8 iv[],
  46                                    u8 const rk2[], int first);
  47
  48 struct aes_block {
  49         u8 b[AES_BLOCK_SIZE];
  50 };
  51
  52 static int num_rounds(struct crypto_aes_ctx *ctx)
  53 {
  54         /*
  55          * # of rounds specified by AES:
  56          * 128 bit key          10 rounds
  57          * 192 bit key          12 rounds
  58          * 256 bit key          14 rounds
  59          * => n byte key        => 6 + (n/4) rounds
  60          */
  61         return 6 + ctx->key_length / 4;
  62 }
  63
  64 static int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
  65                             unsigned int key_len)
  66 {
  67         /*
  68          * The AES key schedule round constants
  69          */
  70         static u8 const rcon[] = {
  71                 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
  72         };
  73
  74         u32 kwords = key_len / sizeof(u32);
  75         struct aes_block *key_enc, *key_dec;
  76         int i, j;
  77
  78         if (key_len != AES_KEYSIZE_128 &&
  79             key_len != AES_KEYSIZE_192 &&
  80             key_len != AES_KEYSIZE_256)
  81                 return -EINVAL;
  82
  83         memcpy(ctx->key_enc, in_key, key_len);
  84         ctx->key_length = key_len;
  85
  86         kernel_neon_begin();
  87         for (i = 0; i < sizeof(rcon); i++) {
  88                 u32 *rki = ctx->key_enc + (i * kwords);
  89                 u32 *rko = rki + kwords;
  90
  91 #ifndef CONFIG_CPU_BIG_ENDIAN
  92                 rko[0] = ror32(ce_aes_sub(rki[kwords - 1]), 8);
  93                 rko[0] = rko[0] ^ rki[0] ^ rcon[i];
  94 #else
  95                 rko[0] = rol32(ce_aes_sub(rki[kwords - 1]), 8);
  96                 rko[0] = rko[0] ^ rki[0] ^ (rcon[i] << 24);
  97 #endif
  98                 rko[1] = rko[0] ^ rki[1];
  99                 rko[2] = rko[1] ^ rki[2];
 100                 rko[3] = rko[2] ^ rki[3];
 101
 102                 if (key_len == AES_KEYSIZE_192) {
 103                         if (i >= 7)
 104                                 break;
 105                         rko[4] = rko[3] ^ rki[4];
 106                         rko[5] = rko[4] ^ rki[5];
 107                 } else if (key_len == AES_KEYSIZE_256) {
 108                         if (i >= 6)
 109                                 break;
 110                         rko[4] = ce_aes_sub(rko[3]) ^ rki[4];
 111                         rko[5] = rko[4] ^ rki[5];
 112                         rko[6] = rko[5] ^ rki[6];
 113                         rko[7] = rko[6] ^ rki[7];
 114                 }
 115         }
 116
 117         /*
 118          * Generate the decryption keys for the Equivalent Inverse Cipher.
 119          * This involves reversing the order of the round keys, and applying
 120          * the Inverse Mix Columns transformation on all but the first and
 121          * the last one.
 122          */
 123         key_enc = (struct aes_block *)ctx->key_enc;
 124         key_dec = (struct aes_block *)ctx->key_dec;
 125         j = num_rounds(ctx);
 126
 127         key_dec[0] = key_enc[j];
 128         for (i = 1, j--; j > 0; i++, j--)
 129                 ce_aes_invert(key_dec + i, key_enc + j);
 130         key_dec[i] = key_enc[0];
 131
 132         kernel_neon_end();
 133         return 0;
 134 }
 135
 136 static int ce_aes_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
 137                          unsigned int key_len)
 138 {
 139         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 140         int ret;
 141
 142         ret = ce_aes_expandkey(ctx, in_key, key_len);
 143         if (!ret)
 144                 return 0;
 145
 146         crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 147         return -EINVAL;
 148 }
 149
 150 struct crypto_aes_xts_ctx {
 151         struct crypto_aes_ctx key1;
 152         struct crypto_aes_ctx __aligned(8) key2;
 153 };
 154
 155 static int xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
 156                        unsigned int key_len)
 157 {
 158         struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 159         int ret;
 160
 161         ret = xts_verify_key(tfm, in_key, key_len);
 162         if (ret)
 163                 return ret;
 164
 165         ret = ce_aes_expandkey(&ctx->key1, in_key, key_len / 2);
 166         if (!ret)
 167                 ret = ce_aes_expandkey(&ctx->key2, &in_key[key_len / 2],
 168                                        key_len / 2);
 169         if (!ret)
 170                 return 0;
 171
 172         crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
 173         return -EINVAL;
 174 }
 175
 176 static int ecb_encrypt(struct skcipher_request *req)
 177 {
 178         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 179         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 180         struct skcipher_walk walk;
 181         unsigned int blocks;
 182         int err;
 183
 184         err = skcipher_walk_virt(&walk, req, true);
 185
 186         kernel_neon_begin();
 187         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 188                 ce_aes_ecb_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 189                                    (u8 *)ctx->key_enc, num_rounds(ctx), blocks);
 190                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 191         }
 192         kernel_neon_end();
 193         return err;
 194 }
 195
 196 static int ecb_decrypt(struct skcipher_request *req)
 197 {
 198         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 199         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 200         struct skcipher_walk walk;
 201         unsigned int blocks;
 202         int err;
 203
 204         err = skcipher_walk_virt(&walk, req, true);
 205
 206         kernel_neon_begin();
 207         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 208                 ce_aes_ecb_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 209                                    (u8 *)ctx->key_dec, num_rounds(ctx), blocks);
 210                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 211         }
 212         kernel_neon_end();
 213         return err;
 214 }
 215
 216 static int cbc_encrypt(struct skcipher_request *req)
 217 {
 218         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 219         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 220         struct skcipher_walk walk;
 221         unsigned int blocks;
 222         int err;
 223
 224         err = skcipher_walk_virt(&walk, req, true);
 225
 226         kernel_neon_begin();
 227         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 228                 ce_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 229                                    (u8 *)ctx->key_enc, num_rounds(ctx), blocks,
 230                                    walk.iv);
 231                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 232         }
 233         kernel_neon_end();
 234         return err;
 235 }
 236
 237 static int cbc_decrypt(struct skcipher_request *req)
 238 {
 239         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 240         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 241         struct skcipher_walk walk;
 242         unsigned int blocks;
 243         int err;
 244
 245         err = skcipher_walk_virt(&walk, req, true);
 246
 247         kernel_neon_begin();
 248         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 249                 ce_aes_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 250                                    (u8 *)ctx->key_dec, num_rounds(ctx), blocks,
 251                                    walk.iv);
 252                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 253         }
 254         kernel_neon_end();
 255         return err;
 256 }
 257
 258 static int ctr_encrypt(struct skcipher_request *req)
 259 {
 260         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 261         struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
 262         struct skcipher_walk walk;
 263         int err, blocks;
 264
 265         err = skcipher_walk_virt(&walk, req, true);
 266
 267         kernel_neon_begin();
 268         while ((blocks = (walk.nbytes / AES_BLOCK_SIZE))) {
 269                 ce_aes_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 270                                    (u8 *)ctx->key_enc, num_rounds(ctx), blocks,
 271                                    walk.iv);
 272                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 273         }
 274         if (walk.nbytes) {
 275                 u8 __aligned(8) tail[AES_BLOCK_SIZE];
 276                 unsigned int nbytes = walk.nbytes;
 277                 u8 *tdst = walk.dst.virt.addr;
 278                 u8 *tsrc = walk.src.virt.addr;
 279
 280                 /*
 281                  * Tell aes_ctr_encrypt() to process a tail block.
 282                  */
 283                 blocks = -1;
 284
 285                 ce_aes_ctr_encrypt(tail, NULL, (u8 *)ctx->key_enc,
 286                                    num_rounds(ctx), blocks, walk.iv);
 287                 if (tdst != tsrc)
 288                         memcpy(tdst, tsrc, nbytes);
 289                 crypto_xor(tdst, tail, nbytes);
 290                 err = skcipher_walk_done(&walk, 0);
 291         }
 292         kernel_neon_end();
 293
 294         return err;
 295 }
 296
 297 static int xts_encrypt(struct skcipher_request *req)
 298 {
 299         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 300         struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 301         int err, first, rounds = num_rounds(&ctx->key1);
 302         struct skcipher_walk walk;
 303         unsigned int blocks;
 304
 305         err = skcipher_walk_virt(&walk, req, true);
 306
 307         kernel_neon_begin();
 308         for (first = 1; (blocks = (walk.nbytes / AES_BLOCK_SIZE)); first = 0) {
 309                 ce_aes_xts_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
 310                                    (u8 *)ctx->key1.key_enc, rounds, blocks,
 311                                    walk.iv, (u8 *)ctx->key2.key_enc, first);
 312                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 313         }
 314         kernel_neon_end();
 315
 316         return err;
 317 }
 318
 319 static int xts_decrypt(struct skcipher_request *req)
 320 {
 321         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 322         struct crypto_aes_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
 323         int err, first, rounds = num_rounds(&ctx->key1);
 324         struct skcipher_walk walk;
 325         unsigned int blocks;
 326
 327         err = skcipher_walk_virt(&walk, req, true);
 328
 329         kernel_neon_begin();
 330         for (first = 1; (blocks = (walk.nbytes / AES_BLOCK_SIZE)); first = 0) {
 331                 ce_aes_xts_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
 332                                    (u8 *)ctx->key1.key_dec, rounds, blocks,
 333                                    walk.iv, (u8 *)ctx->key2.key_enc, first);
 334                 err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
 335         }
 336         kernel_neon_end();
 337
 338         return err;
 339 }
 340
 341 static struct skcipher_alg aes_algs[] = { {
 342         .base = {
 343                 .cra_name               = "__ecb(aes)",
 344                 .cra_driver_name        = "__ecb-aes-ce",
 345                 .cra_priority           = 300,
 346                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 347                 .cra_blocksize          = AES_BLOCK_SIZE,
 348                 .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 349                 .cra_module             = THIS_MODULE,
 350         },
 351         .min_keysize    = AES_MIN_KEY_SIZE,
 352         .max_keysize    = AES_MAX_KEY_SIZE,
 353         .setkey         = ce_aes_setkey,
 354         .encrypt        = ecb_encrypt,
 355         .decrypt        = ecb_decrypt,
 356 }, {
 357         .base = {
 358                 .cra_name               = "__cbc(aes)",
 359                 .cra_driver_name        = "__cbc-aes-ce",
 360                 .cra_priority           = 300,
 361                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 362                 .cra_blocksize          = AES_BLOCK_SIZE,
 363                 .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 364                 .cra_module             = THIS_MODULE,
 365         },
 366         .min_keysize    = AES_MIN_KEY_SIZE,
 367         .max_keysize    = AES_MAX_KEY_SIZE,
 368         .ivsize         = AES_BLOCK_SIZE,
 369         .setkey         = ce_aes_setkey,
 370         .encrypt        = cbc_encrypt,
 371         .decrypt        = cbc_decrypt,
 372 }, {
 373         .base = {
 374                 .cra_name               = "__ctr(aes)",
 375                 .cra_driver_name        = "__ctr-aes-ce",
 376                 .cra_priority           = 300,
 377                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 378                 .cra_blocksize          = 1,
 379                 .cra_ctxsize            = sizeof(struct crypto_aes_ctx),
 380                 .cra_module             = THIS_MODULE,
 381         },
 382         .min_keysize    = AES_MIN_KEY_SIZE,
 383         .max_keysize    = AES_MAX_KEY_SIZE,
 384         .ivsize         = AES_BLOCK_SIZE,
 385         .chunksize      = AES_BLOCK_SIZE,
 386         .setkey         = ce_aes_setkey,
 387         .encrypt        = ctr_encrypt,
 388         .decrypt        = ctr_encrypt,
 389 }, {
 390         .base = {
 391                 .cra_name               = "__xts(aes)",
 392                 .cra_driver_name        = "__xts-aes-ce",
 393                 .cra_priority           = 300,
 394                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 395                 .cra_blocksize          = AES_BLOCK_SIZE,
 396                 .cra_ctxsize            = sizeof(struct crypto_aes_xts_ctx),
 397                 .cra_module             = THIS_MODULE,
 398         },
 399         .min_keysize    = 2 * AES_MIN_KEY_SIZE,
 400         .max_keysize    = 2 * AES_MAX_KEY_SIZE,
 401         .ivsize         = AES_BLOCK_SIZE,
 402         .setkey         = xts_set_key,
 403         .encrypt        = xts_encrypt,
 404         .decrypt        = xts_decrypt,
 405 } };
 406
 407 static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
 408
 409 static void aes_exit(void)
 410 {
 411         int i;
 412
 413         for (i = 0; i < ARRAY_SIZE(aes_simd_algs) && aes_simd_algs[i]; i++)
 414                 simd_skcipher_free(aes_simd_algs[i]);
 415
 416         crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 417 }
 418
 419 static int __init aes_init(void)
 420 {
 421         struct simd_skcipher_alg *simd;
 422         const char *basename;
 423         const char *algname;
 424         const char *drvname;
 425         int err;
 426         int i;
 427
 428         if (!(elf_hwcap2 & HWCAP2_AES))
 429                 return -ENODEV;
 430
 431         err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
 432         if (err)
 433                 return err;
 434
 435         for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
 436                 algname = aes_algs[i].base.cra_name + 2;
 437                 drvname = aes_algs[i].base.cra_driver_name + 2;
 438                 basename = aes_algs[i].base.cra_driver_name;
 439                 simd = simd_skcipher_create_compat(algname, drvname, basename);
 440                 err = PTR_ERR(simd);
 441                 if (IS_ERR(simd))
 442                         goto unregister_simds;
 443
 444                 aes_simd_algs[i] = simd;
 445         }
 446
 447         return 0;
 448
 449 unregister_simds:
 450         aes_exit();
 451         return err;
 452 }
 453
 454 module_init(aes_init);
 455 module_exit(aes_exit);