[linux-2.6-block.git] / crypto / ghash-generic.c

/*
 * 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/ghash.h>
#include <crypto/internal/hash.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>

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_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_CRYPTO("ghash");
MODULE_ALIAS_CRYPTO("ghash-generic");
Commit	Line	Data
2cdc6899 HY	1	/*
	2	* GHASH: digest algorithm for GCM (Galois/Counter Mode).
	3	*
	4	* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
	5	* Copyright (c) 2009 Intel Corp.
	6	* Author: Huang Ying <ying.huang@intel.com>
	7	*
	8	* The algorithm implementation is copied from gcm.c.
	9	*
	10	* This program is free software; you can redistribute it and/or modify it
	11	* under the terms of the GNU General Public License version 2 as published
	12	* by the Free Software Foundation.
	13	*/
	14
	15	#include <crypto/algapi.h>
	16	#include <crypto/gf128mul.h>
a397ba82	17	#include <crypto/ghash.h>
2cdc6899 HY	18	#include <crypto/internal/hash.h>
	19	#include <linux/crypto.h>
	20	#include <linux/init.h>
	21	#include <linux/kernel.h>
	22	#include <linux/module.h>
	23
2cdc6899 HY	24	static int ghash_init(struct shash_desc *desc)
	25	{
	26	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
	27
	28	memset(dctx, 0, sizeof(*dctx));
	29
	30	return 0;
	31	}
	32
	33	static int ghash_setkey(struct crypto_shash *tfm,
	34	const u8 *key, unsigned int keylen)
	35	{
	36	struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
	37
	38	if (keylen != GHASH_BLOCK_SIZE) {
	39	crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
	40	return -EINVAL;
	41	}
	42
	43	if (ctx->gf128)
	44	gf128mul_free_4k(ctx->gf128);
	45	ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
	46	if (!ctx->gf128)
	47	return -ENOMEM;
	48
	49	return 0;
	50	}
	51
	52	static int ghash_update(struct shash_desc *desc,
	53	const u8 *src, unsigned int srclen)
	54	{
	55	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
	56	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
	57	u8 *dst = dctx->buffer;
	58
	59	if (dctx->bytes) {
	60	int n = min(srclen, dctx->bytes);
	61	u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
	62
	63	dctx->bytes -= n;
	64	srclen -= n;
	65
	66	while (n--)
	67	pos++ ^= src++;
	68
	69	if (!dctx->bytes)
	70	gf128mul_4k_lle((be128 *)dst, ctx->gf128);
	71	}
	72
	73	while (srclen >= GHASH_BLOCK_SIZE) {
	74	crypto_xor(dst, src, GHASH_BLOCK_SIZE);
	75	gf128mul_4k_lle((be128 *)dst, ctx->gf128);
	76	src += GHASH_BLOCK_SIZE;
	77	srclen -= GHASH_BLOCK_SIZE;
	78	}
	79
	80	if (srclen) {
	81	dctx->bytes = GHASH_BLOCK_SIZE - srclen;
	82	while (srclen--)
	83	dst++ ^= src++;
	84	}
	85
	86	return 0;
	87	}
88
89	static void ghash_flush(struct ghash_ctx ctx, struct ghash_desc_ctx dctx)
90	{
91	u8 *dst = dctx->buffer;
92
93	if (dctx->bytes) {
94	u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
95
96	while (dctx->bytes--)
97	*tmp++ ^= 0;
98
99	gf128mul_4k_lle((be128 *)dst, ctx->gf128);
100	}
101
102	dctx->bytes = 0;
103	}
104
105	static int ghash_final(struct shash_desc desc, u8 dst)
106	{
107	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
108	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
109	u8 *buf = dctx->buffer;
110
111	ghash_flush(ctx, dctx);
112	memcpy(dst, buf, GHASH_BLOCK_SIZE);
113
114	return 0;
115	}
116
117	static void ghash_exit_tfm(struct crypto_tfm *tfm)
118	{
119	struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
120	if (ctx->gf128)
121	gf128mul_free_4k(ctx->gf128);
122	}
123
124	static struct shash_alg ghash_alg = {
125	.digestsize = GHASH_DIGEST_SIZE,
126	.init = ghash_init,
127	.update = ghash_update,
128	.final = ghash_final,
129	.setkey = ghash_setkey,
130	.descsize = sizeof(struct ghash_desc_ctx),
131	.base = {
132	.cra_name = "ghash",
133	.cra_driver_name = "ghash-generic",
134	.cra_priority = 100,
135	.cra_flags = CRYPTO_ALG_TYPE_SHASH,
136	.cra_blocksize = GHASH_BLOCK_SIZE,
137	.cra_ctxsize = sizeof(struct ghash_ctx),
138	.cra_module = THIS_MODULE,
2cdc6899 HY	139	.cra_exit = ghash_exit_tfm,
	140	},
	141	};
	142
	143	static int __init ghash_mod_init(void)
	144	{
	145	return crypto_register_shash(&ghash_alg);
	146	}
	147
	148	static void __exit ghash_mod_exit(void)
	149	{
	150	crypto_unregister_shash(&ghash_alg);
	151	}
	152
	153	module_init(ghash_mod_init);
	154	module_exit(ghash_mod_exit);
	155
	156	MODULE_LICENSE("GPL");
	157	MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
5d26a105	158	MODULE_ALIAS_CRYPTO("ghash");
3e14dcf7	159	MODULE_ALIAS_CRYPTO("ghash-generic");