crypto: ghash - Add GHASH digest algorithm for GCM

GHASH is implemented as a shash algorithm. The actual implementation
is copied from gcm.c. This makes it possible to add
architecture/hardware accelerated GHASH implementation.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Huang Ying 2009-08-06 15:32:38 +10:00 committed by Herbert Xu
parent cbdcf80d8b
commit 2cdc6899a8
3 changed files with 178 additions and 0 deletions

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@ -290,6 +290,13 @@ config CRYPTO_CRC32C_INTEL
gain performance compared with software implementation.
Module will be crc32c-intel.
config CRYPTO_GHASH
tristate "GHASH digest algorithm"
select CRYPTO_SHASH
select CRYPTO_GF128MUL
help
GHASH is message digest algorithm for GCM (Galois/Counter Mode).
config CRYPTO_MD4
tristate "MD4 digest algorithm"
select CRYPTO_HASH

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@ -82,6 +82,7 @@ obj-$(CONFIG_CRYPTO_RNG2) += rng.o
obj-$(CONFIG_CRYPTO_RNG2) += krng.o
obj-$(CONFIG_CRYPTO_ANSI_CPRNG) += ansi_cprng.o
obj-$(CONFIG_CRYPTO_TEST) += tcrypt.o
obj-$(CONFIG_CRYPTO_GHASH) += ghash-generic.o
#
# generic algorithms and the async_tx api

170
crypto/ghash-generic.c Normal file
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@ -0,0 +1,170 @@
/*
* GHASH: digest algorithm for GCM (Galois/Counter Mode).
*
* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
* Copyright (c) 2009 Intel Corp.
* Author: Huang Ying <ying.huang@intel.com>
*
* The algorithm implementation is copied from gcm.c.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*/
#include <crypto/algapi.h>
#include <crypto/gf128mul.h>
#include <crypto/internal/hash.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#define GHASH_BLOCK_SIZE 16
#define GHASH_DIGEST_SIZE 16
struct ghash_ctx {
struct gf128mul_4k *gf128;
};
struct ghash_desc_ctx {
u8 buffer[GHASH_BLOCK_SIZE];
u32 bytes;
};
static int ghash_init(struct shash_desc *desc)
{
struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
memset(dctx, 0, sizeof(*dctx));
return 0;
}
static int ghash_setkey(struct crypto_shash *tfm,
const u8 *key, unsigned int keylen)
{
struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
if (keylen != GHASH_BLOCK_SIZE) {
crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
return -EINVAL;
}
if (ctx->gf128)
gf128mul_free_4k(ctx->gf128);
ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
if (!ctx->gf128)
return -ENOMEM;
return 0;
}
static int ghash_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
u8 *dst = dctx->buffer;
if (dctx->bytes) {
int n = min(srclen, dctx->bytes);
u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
dctx->bytes -= n;
srclen -= n;
while (n--)
*pos++ ^= *src++;
if (!dctx->bytes)
gf128mul_4k_lle((be128 *)dst, ctx->gf128);
}
while (srclen >= GHASH_BLOCK_SIZE) {
crypto_xor(dst, src, GHASH_BLOCK_SIZE);
gf128mul_4k_lle((be128 *)dst, ctx->gf128);
src += GHASH_BLOCK_SIZE;
srclen -= GHASH_BLOCK_SIZE;
}
if (srclen) {
dctx->bytes = GHASH_BLOCK_SIZE - srclen;
while (srclen--)
*dst++ ^= *src++;
}
return 0;
}
static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
{
u8 *dst = dctx->buffer;
if (dctx->bytes) {
u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
while (dctx->bytes--)
*tmp++ ^= 0;
gf128mul_4k_lle((be128 *)dst, ctx->gf128);
}
dctx->bytes = 0;
}
static int ghash_final(struct shash_desc *desc, u8 *dst)
{
struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
u8 *buf = dctx->buffer;
ghash_flush(ctx, dctx);
memcpy(dst, buf, GHASH_BLOCK_SIZE);
return 0;
}
static void ghash_exit_tfm(struct crypto_tfm *tfm)
{
struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
if (ctx->gf128)
gf128mul_free_4k(ctx->gf128);
}
static struct shash_alg ghash_alg = {
.digestsize = GHASH_DIGEST_SIZE,
.init = ghash_init,
.update = ghash_update,
.final = ghash_final,
.setkey = ghash_setkey,
.descsize = sizeof(struct ghash_desc_ctx),
.base = {
.cra_name = "ghash",
.cra_driver_name = "ghash-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_SHASH,
.cra_blocksize = GHASH_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct ghash_ctx),
.cra_module = THIS_MODULE,
.cra_list = LIST_HEAD_INIT(ghash_alg.base.cra_list),
.cra_exit = ghash_exit_tfm,
},
};
static int __init ghash_mod_init(void)
{
return crypto_register_shash(&ghash_alg);
}
static void __exit ghash_mod_exit(void)
{
crypto_unregister_shash(&ghash_alg);
}
module_init(ghash_mod_init);
module_exit(ghash_mod_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
MODULE_ALIAS("ghash");