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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Accelerated GHASH implementation with Intel PCLMULQDQ-NI
   4  * instructions. This file contains glue code.
   5  *
   6  * Copyright (c) 2009 Intel Corp.
   7  *   Author: Huang Ying <ying.huang@intel.com>
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/crypto.h>
  15 #include <crypto/algapi.h>
  16 #include <crypto/cryptd.h>
  17 #include <crypto/gf128mul.h>
  18 #include <crypto/internal/hash.h>
  19 #include <crypto/internal/simd.h>
  20 #include <asm/cpu_device_id.h>
  21 #include <asm/simd.h>
  22 #include <asm/unaligned.h>
  23
  24 #define GHASH_BLOCK_SIZE        16
  25 #define GHASH_DIGEST_SIZE       16
  26
  27 void clmul_ghash_mul(char *dst, const le128 *shash);
  28
  29 void clmul_ghash_update(char *dst, const char *src, unsigned int srclen,
  30                         const le128 *shash);
  31
  32 struct ghash_async_ctx {
  33         struct cryptd_ahash *cryptd_tfm;
  34 };
  35
  36 struct ghash_ctx {
  37         le128 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         u64 a, b;
  59
  60         if (keylen != GHASH_BLOCK_SIZE)
  61                 return -EINVAL;
  62
  63         /*
  64          * GHASH maps bits to polynomial coefficients backwards, which makes it
  65          * hard to implement.  But it can be shown that the GHASH multiplication
  66          *
  67          *      D * K (mod x^128 + x^7 + x^2 + x + 1)
  68          *
  69          * (where D is a data block and K is the key) is equivalent to:
  70          *
  71          *      bitreflect(D) * bitreflect(K) * x^(-127)
  72          *              (mod x^128 + x^127 + x^126 + x^121 + 1)
  73          *
  74          * So, the code below precomputes:
  75          *
  76          *      bitreflect(K) * x^(-127) (mod x^128 + x^127 + x^126 + x^121 + 1)
  77          *
  78          * ... but in Montgomery form (so that Montgomery multiplication can be
  79          * used), i.e. with an extra x^128 factor, which means actually:
  80          *
  81          *      bitreflect(K) * x (mod x^128 + x^127 + x^126 + x^121 + 1)
  82          *
  83          * The within-a-byte part of bitreflect() cancels out GHASH's built-in
  84          * reflection, and thus bitreflect() is actually a byteswap.
  85          */
  86         a = get_unaligned_be64(key);
  87         b = get_unaligned_be64(key + 8);
  88         ctx->shash.a = cpu_to_le64((a << 1) | (b >> 63));
  89         ctx->shash.b = cpu_to_le64((b << 1) | (a >> 63));
  90         if (a >> 63)
  91                 ctx->shash.a ^= cpu_to_le64((u64)0xc2 << 56);
  92         return 0;
  93 }
  94
  95 static int ghash_update(struct shash_desc *desc,
  96                          const u8 *src, unsigned int srclen)
  97 {
  98         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
  99         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
 100         u8 *dst = dctx->buffer;
 101
 102         kernel_fpu_begin();
 103         if (dctx->bytes) {
 104                 int n = min(srclen, dctx->bytes);
 105                 u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
 106
 107                 dctx->bytes -= n;
 108                 srclen -= n;
 109
 110                 while (n--)
 111                         *pos++ ^= *src++;
 112
 113                 if (!dctx->bytes)
 114                         clmul_ghash_mul(dst, &ctx->shash);
 115         }
 116
 117         clmul_ghash_update(dst, src, srclen, &ctx->shash);
 118         kernel_fpu_end();
 119
 120         if (srclen & 0xf) {
 121                 src += srclen - (srclen & 0xf);
 122                 srclen &= 0xf;
 123                 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
 124                 while (srclen--)
 125                         *dst++ ^= *src++;
 126         }
 127
 128         return 0;
 129 }
 130
 131 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
 132 {
 133         u8 *dst = dctx->buffer;
 134
 135         if (dctx->bytes) {
 136                 u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
 137
 138                 while (dctx->bytes--)
 139                         *tmp++ ^= 0;
 140
 141                 kernel_fpu_begin();
 142                 clmul_ghash_mul(dst, &ctx->shash);
 143                 kernel_fpu_end();
 144         }
 145
 146         dctx->bytes = 0;
 147 }
 148
 149 static int ghash_final(struct shash_desc *desc, u8 *dst)
 150 {
 151         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 152         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
 153         u8 *buf = dctx->buffer;
 154
 155         ghash_flush(ctx, dctx);
 156         memcpy(dst, buf, GHASH_BLOCK_SIZE);
 157
 158         return 0;
 159 }
 160
 161 static struct shash_alg ghash_alg = {
 162         .digestsize     = GHASH_DIGEST_SIZE,
 163         .init           = ghash_init,
 164         .update         = ghash_update,
 165         .final          = ghash_final,
 166         .setkey         = ghash_setkey,
 167         .descsize       = sizeof(struct ghash_desc_ctx),
 168         .base           = {
 169                 .cra_name               = "__ghash",
 170                 .cra_driver_name        = "__ghash-pclmulqdqni",
 171                 .cra_priority           = 0,
 172                 .cra_flags              = CRYPTO_ALG_INTERNAL,
 173                 .cra_blocksize          = GHASH_BLOCK_SIZE,
 174                 .cra_ctxsize            = sizeof(struct ghash_ctx),
 175                 .cra_module             = THIS_MODULE,
 176         },
 177 };
 178
 179 static int ghash_async_init(struct ahash_request *req)
 180 {
 181         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 182         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 183         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 184         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 185         struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 186         struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
 187
 188         desc->tfm = child;
 189         return crypto_shash_init(desc);
 190 }
 191
 192 static int ghash_async_update(struct ahash_request *req)
 193 {
 194         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 195         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 196         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 197         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 198
 199         if (!crypto_simd_usable() ||
 200             (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
 201                 memcpy(cryptd_req, req, sizeof(*req));
 202                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 203                 return crypto_ahash_update(cryptd_req);
 204         } else {
 205                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 206                 return shash_ahash_update(req, desc);
 207         }
 208 }
 209
 210 static int ghash_async_final(struct ahash_request *req)
 211 {
 212         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 213         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 214         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 215         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 216
 217         if (!crypto_simd_usable() ||
 218             (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
 219                 memcpy(cryptd_req, req, sizeof(*req));
 220                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 221                 return crypto_ahash_final(cryptd_req);
 222         } else {
 223                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 224                 return crypto_shash_final(desc, req->result);
 225         }
 226 }
 227
 228 static int ghash_async_import(struct ahash_request *req, const void *in)
 229 {
 230         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 231         struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 232         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 233
 234         ghash_async_init(req);
 235         memcpy(dctx, in, sizeof(*dctx));
 236         return 0;
 237
 238 }
 239
 240 static int ghash_async_export(struct ahash_request *req, void *out)
 241 {
 242         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 243         struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 244         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
 245
 246         memcpy(out, dctx, sizeof(*dctx));
 247         return 0;
 248
 249 }
 250
 251 static int ghash_async_digest(struct ahash_request *req)
 252 {
 253         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 254         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 255         struct ahash_request *cryptd_req = ahash_request_ctx(req);
 256         struct cryptd_ahash *cryptd_tfm = ctx->cryptd_tfm;
 257
 258         if (!crypto_simd_usable() ||
 259             (in_atomic() && cryptd_ahash_queued(cryptd_tfm))) {
 260                 memcpy(cryptd_req, req, sizeof(*req));
 261                 ahash_request_set_tfm(cryptd_req, &cryptd_tfm->base);
 262                 return crypto_ahash_digest(cryptd_req);
 263         } else {
 264                 struct shash_desc *desc = cryptd_shash_desc(cryptd_req);
 265                 struct crypto_shash *child = cryptd_ahash_child(cryptd_tfm);
 266
 267                 desc->tfm = child;
 268                 return shash_ahash_digest(req, desc);
 269         }
 270 }
 271
 272 static int ghash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
 273                               unsigned int keylen)
 274 {
 275         struct ghash_async_ctx *ctx = crypto_ahash_ctx(tfm);
 276         struct crypto_ahash *child = &ctx->cryptd_tfm->base;
 277
 278         crypto_ahash_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 279         crypto_ahash_set_flags(child, crypto_ahash_get_flags(tfm)
 280                                & CRYPTO_TFM_REQ_MASK);
 281         return crypto_ahash_setkey(child, key, keylen);
 282 }
 283
 284 static int ghash_async_init_tfm(struct crypto_tfm *tfm)
 285 {
 286         struct cryptd_ahash *cryptd_tfm;
 287         struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
 288
 289         cryptd_tfm = cryptd_alloc_ahash("__ghash-pclmulqdqni",
 290                                         CRYPTO_ALG_INTERNAL,
 291                                         CRYPTO_ALG_INTERNAL);
 292         if (IS_ERR(cryptd_tfm))
 293                 return PTR_ERR(cryptd_tfm);
 294         ctx->cryptd_tfm = cryptd_tfm;
 295         crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
 296                                  sizeof(struct ahash_request) +
 297                                  crypto_ahash_reqsize(&cryptd_tfm->base));
 298
 299         return 0;
 300 }
 301
 302 static void ghash_async_exit_tfm(struct crypto_tfm *tfm)
 303 {
 304         struct ghash_async_ctx *ctx = crypto_tfm_ctx(tfm);
 305
 306         cryptd_free_ahash(ctx->cryptd_tfm);
 307 }
 308
 309 static struct ahash_alg ghash_async_alg = {
 310         .init           = ghash_async_init,
 311         .update         = ghash_async_update,
 312         .final          = ghash_async_final,
 313         .setkey         = ghash_async_setkey,
 314         .digest         = ghash_async_digest,
 315         .export         = ghash_async_export,
 316         .import         = ghash_async_import,
 317         .halg = {
 318                 .digestsize     = GHASH_DIGEST_SIZE,
 319                 .statesize = sizeof(struct ghash_desc_ctx),
 320                 .base = {
 321                         .cra_name               = "ghash",
 322                         .cra_driver_name        = "ghash-clmulni",
 323                         .cra_priority           = 400,
 324                         .cra_ctxsize            = sizeof(struct ghash_async_ctx),
 325                         .cra_flags              = CRYPTO_ALG_ASYNC,
 326                         .cra_blocksize          = GHASH_BLOCK_SIZE,
 327                         .cra_module             = THIS_MODULE,
 328                         .cra_init               = ghash_async_init_tfm,
 329                         .cra_exit               = ghash_async_exit_tfm,
 330                 },
 331         },
 332 };
 333
 334 static const struct x86_cpu_id pcmul_cpu_id[] = {
 335         X86_MATCH_FEATURE(X86_FEATURE_PCLMULQDQ, NULL), /* Pickle-Mickle-Duck */
 336         {}
 337 };
 338 MODULE_DEVICE_TABLE(x86cpu, pcmul_cpu_id);
 339
 340 static int __init ghash_pclmulqdqni_mod_init(void)
 341 {
 342         int err;
 343
 344         if (!x86_match_cpu(pcmul_cpu_id))
 345                 return -ENODEV;
 346
 347         err = crypto_register_shash(&ghash_alg);
 348         if (err)
 349                 goto err_out;
 350         err = crypto_register_ahash(&ghash_async_alg);
 351         if (err)
 352                 goto err_shash;
 353
 354         return 0;
 355
 356 err_shash:
 357         crypto_unregister_shash(&ghash_alg);
 358 err_out:
 359         return err;
 360 }
 361
 362 static void __exit ghash_pclmulqdqni_mod_exit(void)
 363 {
 364         crypto_unregister_ahash(&ghash_async_alg);
 365         crypto_unregister_shash(&ghash_alg);
 366 }
 367
 368 module_init(ghash_pclmulqdqni_mod_init);
 369 module_exit(ghash_pclmulqdqni_mod_exit);
 370
 371 MODULE_LICENSE("GPL");
 372 MODULE_DESCRIPTION("GHASH hash function, accelerated by PCLMULQDQ-NI");
 373 MODULE_ALIAS_CRYPTO("ghash");