arch/x86/crypto/ghash-clmulni-intel_glue.c

   1 /*
   2  * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
   3  * instructions. This file contains glue code.
   4  *
   5  * Copyright (c) 2009 Intel Corp.
   6  *   Author: Huang Ying <ying.huang@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published
  10  * by the Free Software Foundation.
  11  */
  12
  13 #include <linux/err.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/crypto.h>
  18 #include <crypto/algapi.h>
  19 #include <crypto/cryptd.h>
  20 #include <crypto/gf128mul.h>
  21 #include <crypto/internal/hash.h>
  22 #include <asm/i387.h>
  23
  24 #define GHASH_BLOCK_SIZE        16
  25 #define GHASH_DIGEST_SIZE       16
  26
  27 void clmul_ghash_mul(char *dst, const be128 *shash);
  28
  29 void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
  30                         const be128 *shash);
  31
  32 struct ghash_async_ctx {
  33         struct cryptd_ahash *cryptd_tfm;
  34 };
  35
  36 struct ghash_ctx {
  37         be128 shash;
  38 };
  39
  40 struct ghash_desc_ctx {
  41         u8 buffer[GHASH_BLOCK_SIZE];
  42         u32 bytes;
  43 };
  44
  45 static int ghash_init(struct shash_desc *desc)
  46 {
  47         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  48
  49         memset(dctx, 0, sizeof(*dctx));
  50
  51         return 0;
  52 }
  53
  54 static int ghash_setkey(struct crypto_shash *tfm,
  55                         const u8 *key, unsigned int keylen)
  56 {
  57         struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
  58         be128 *x = (be128 *)key;
  59         u64 a, b;
  60
  61         if (keylen != GHASH_BLOCK_SIZE) {
  62                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  63                 return -EINVAL;
  64         }
  65
  66         /* perform multiplication by 'x' in GF(2^128) */
  67         a = be64_to_cpu(x->a);
  68         b = be64_to_cpu(x->b);
  69
  70         ctx->shash.a = (__be64)((b << 1) | (a >> 63));
  71         ctx->shash.b = (__be64)((a << 1) | (b >> 63));
  72
  73         if (a >> 63)
  74                 ctx->shash.b ^= cpu_to_be64(0xc2);
  75
  76         return 0;
  77 }
  78
  79 static int ghash_update(struct shash_desc *desc,
  80                          const u8 *src, unsigned int srclen)
  81 {
  82         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  83         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
  84         u8 *dst = dctx->buffer;
  85
  86         kernel_fpu_begin();
  87         if (dctx->bytes) {
  88                 int n = min(srclen, dctx->bytes);
  89                 u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
  90
  91                 dctx->bytes -= n;
  92                 srclen -= n;
  93
  94                 while (n--)
  95                         *pos++ ^= *src++;
  96
  97                 if (!dctx->bytes)
  98                         clmul_ghash_mul(dst, &ctx->shash);
  99         }
 100
 101         clmul_ghash_update(dst, src, srclen, &ctx->shash);
 102         kernel_fpu_end();
 103
 104         if (srclen & 0xf) {
 105                 src += srclen - (srclen & 0xf);
 106                 srclen &= 0xf;
 107                 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
 108                 while (srclen--)
 109                         *dst++ ^= *src++;
 110         }
 111
 112         return 0;
 113 }
 114
 115 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
 116 {
 117         u8 *dst = dctx->buffer;
 118
 119         if (dctx->bytes) {
 120                 u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
 121
 122                 while (dctx->bytes--)
 123                         *tmp++ ^= 0;
 124
 125                 kernel_fpu_begin();
 126                 clmul_ghash_mul(dst, &ctx->shash);
 127                 kernel_fpu_end();
 128         }
 129
 130         dctx->bytes = 0;
 131 }
 132
 133 static int ghash_final(struct shash_desc *desc, u8 *dst)
 134 {
 135         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 136         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
 137         u8 *buf = dctx->buffer;
 138
 139         ghash_flush(ctx, dctx);
 140         memcpy(dst, buf, GHASH_BLOCK_SIZE);
 141
 142         return 0;
 143 }
 144
 145 static struct shash_alg ghash_alg = {
 146         .digestsize     = GHASH_DIGEST_SIZE,
 147         .init           = ghash_init,
 148         .update         = ghash_update,
 149         .final          = ghash_final,
 150         .setkey         = ghash_setkey,
 151         .descsize       = sizeof(struct ghash_desc_ctx),
 152         .base           = {
 153                 .cra_name               = "__ghash",
 154                 .cra_driver_name        = "__ghash-pclmulqdqni",
 155                 .cra_priority           = 0,
 156                 .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
 157                 .cra_blocksize          = GHASH_BLOCK_SIZE,
 158                 .cra_ctxsize            = sizeof(struct ghash_ctx),
 159                 .cra_module             = THIS_MODULE,
 160                 .cra_list               = LIST_HEAD_INIT(ghash_alg.base.cra_list),
 161         },
 162 };
 163
 164 static int ghash_async_init(struct ahash_request *req)
 165 {
 166         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 167         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 168         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 169         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 170
 171         if (!irq_fpu_usable()) {
 172                 memcpy(cryptd_req, req, sizeof(*req));
 173                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 174                 return crypto_ahash_init(cryptd_req);
 175         } else {
 176                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 177                 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
 178
 179                 desc->tfm = child;
 180                 desc->flags = req->base.flags;
 181                 return crypto_shash_init(desc);
 182         }
 183 }
 184
 185 static int ghash_async_update(struct ahash_request *req)
 186 {
 187         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 188
 189         if (!irq_fpu_usable()) {
 190                 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 191                 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 192                 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 193
 194                 memcpy(cryptd_req, req, sizeof(*req));
 195                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 196                 return crypto_ahash_update(cryptd_req);
 197         } else {
 198                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 199                 return shash_ahash_update(req, desc);
 200         }
 201 }
 202
 203 static int ghash_async_final(struct ahash_request *req)
 204 {
 205         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 206
 207         if (!irq_fpu_usable()) {
 208                 struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 209                 struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 210                 struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 211
 212                 memcpy(cryptd_req, req, sizeof(*req));
 213                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 214                 return crypto_ahash_final(cryptd_req);
 215         } else {
 216                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 217                 return crypto_shash_final(desc, req->result);
 218         }
 219 }
 220
 221 static int ghash_async_digest(struct ahash_request *req)
 222 {
 223         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 224         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 225         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 226         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 227
 228         if (!irq_fpu_usable()) {
 229                 memcpy(cryptd_req, req, sizeof(*req));
 230                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 231                 return crypto_ahash_digest(cryptd_req);
 232         } else {
 233                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 234                 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
 235
 236                 desc->tfm = child;
 237                 desc->flags = req->base.flags;
 238                 return shash_ahash_digest(req, desc);
 239         }
 240 }
 241
 242 static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
 243                               unsigned int keylen)
 244 {
 245         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 246         struct crypto_ahash *child = &ctx->cryptd_tfm->base;
 247         int err;
 248
 249         crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 250         crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
 251                                & CRYPTO_TFM_REQ_MASK);
 252         err = crypto_ahash_setkey(child, key, keylen);
 253         crypto_ahash_set_flags(tfm, crypto_ahash_get_flags(child)
 254                                & CRYPTO_TFM_RES_MASK);
 255
 256         return err;
 257 }
 258
 259 static int ghash_async_init_tfm(struct crypto_tfm *tfm)
 260 {
 261         struct cryptd_ahash *cryptd_tfm;
 262         struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
 263
 264         cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni", 0, 0);
 265         if (IS_ERR(cryptd_tfm))
 266                 return PTR_ERR(cryptd_tfm);
 267         ctx->cryptd_tfm = cryptd_tfm;
 268         crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
 269                                  sizeof(struct ahash_request) +
 270                                  crypto_ahash_reqsize(&cryptd_tfm->base));
 271
 272         return 0;
 273 }
 274
 275 static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
 276 {
 277         struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
 278
 279         cryptd_free_ahash(ctx->cryptd_tfm);
 280 }
 281
 282 static struct ahash_alg ghash_async_alg = {
 283         .init           = ghash_async_init,
 284         .update         = ghash_async_update,
 285         .final          = ghash_async_final,
 286         .setkey         = ghash_async_setkey,
 287         .digest         = ghash_async_digest,
 288         .halg = {
 289                 .digestsize     = GHASH_DIGEST_SIZE,
 290                 .base = {
 291                         .cra_name               = "ghash",
 292                         .cra_driver_name        = "ghash-clmulni",
 293                         .cra_priority           = 400,
 294                         .cra_flags              = CRYPTO_ALG_TYPE_AHASH | CRYPTO_ALG_ASYNC,
 295                         .cra_blocksize          = GHASH_BLOCK_SIZE,
 296                         .cra_type               = &crypto_ahash_type,
 297                         .cra_module             = THIS_MODULE,
 298                         .cra_list               = LIST_HEAD_INIT(ghash_async_alg.halg.base.cra_list),
 299                         .cra_init               = ghash_async_init_tfm,
 300                         .cra_exit               = ghash_async_exit_tfm,
 301                 },
 302         },
 303 };
 304
 305 static int __init ghash_pclmulqdqni_mod_init(void)
 306 {
 307         int err;
 308
 309         if (!cpu_has_pclmulqdq) {
 310                 printk(KERN_INFO "Intel PCLMULQDQ-NI instructions are not"
 311                        " detected.\n");
 312                 return -ENODEV;
 313         }
 314
 315         err = crypto_register_shash(&ghash_alg);
 316         if (err)
 317                 goto err_out;
 318         err = crypto_register_ahash(&ghash_async_alg);
 319         if (err)
 320                 goto err_shash;
 321
 322         return 0;
 323
 324 err_shash:
 325         crypto_unregister_shash(&ghash_alg);
 326 err_out:
 327         return err;
 328 }
 329
 330 static void __exit ghash_pclmulqdqni_mod_exit(void)
 331 {
 332         crypto_unregister_ahash(&ghash_async_alg);
 333         crypto_unregister_shash(&ghash_alg);
 334 }
 335
 336 module_init(ghash_pclmulqdqni_mod_init);
 337 module_exit(ghash_pclmulqdqni_mod_exit);
 338
 339 MODULE_LICENSE("GPL");
 340 MODULE_DESCRIPTION("GHASH Message Digest Algorithm, "
 341                    "acclerated by PCLMULQDQ-NI");
 342 MODULE_ALIAS("ghash");