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Commit 2cdc6899 authored by Huang Ying's avatar Huang Ying Committed by Herbert Xu
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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: default avatarHuang Ying <ying.huang@intel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent cbdcf80d

crypto/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -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

crypto/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

crypto/ghash-generic.c

0 → 100644
+170 −0
Original line number Diff line number Diff line 
/*

 * 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");