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

/*
 * GHASH: digest algorithm for GCM (Galois/Counter Mode).
 *
 * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <[email protected]>
 * Copyright (c) 2009 Intel Corp.
 *   Author: Huang Ying <[email protected]>
 *
 * 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 (!ctx->gf128)
		return -ENOKEY;

	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;

	if (!ctx->gf128)
		return -ENOKEY;

	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("ghash");
Commit	Line	Data
2cdc6899 YH	1	/*
	2	* GHASH: digest algorithm for GCM (Galois/Counter Mode).
	3	*
	4	* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <[email protected]>
	5	* Copyright (c) 2009 Intel Corp.
	6	* Author: Huang Ying <[email protected]>
	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>
	17	#include <crypto/internal/hash.h>
	18	#include <linux/crypto.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/module.h>
	22
	23	#define GHASH_BLOCK_SIZE 16
	24	#define GHASH_DIGEST_SIZE 16
	25
	26	struct ghash_ctx {
	27	struct gf128mul_4k *gf128;
	28	};
	29
	30	struct ghash_desc_ctx {
	31	u8 buffer[GHASH_BLOCK_SIZE];
	32	u32 bytes;
	33	};
	34
	35	static int ghash_init(struct shash_desc *desc)
	36	{
	37	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
	38
	39	memset(dctx, 0, sizeof(*dctx));
	40
	41	return 0;
	42	}
	43
	44	static int ghash_setkey(struct crypto_shash *tfm,
	45	const u8 *key, unsigned int keylen)
	46	{
	47	struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
	48
	49	if (keylen != GHASH_BLOCK_SIZE) {
	50	crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
	51	return -EINVAL;
	52	}
	53
	54	if (ctx->gf128)
	55	gf128mul_free_4k(ctx->gf128);
	56	ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
	57	if (!ctx->gf128)
	58	return -ENOMEM;
	59
	60	return 0;
	61	}
	62
	63	static int ghash_update(struct shash_desc *desc,
	64	const u8 *src, unsigned int srclen)
65	{
66	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
67	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
68	u8 *dst = dctx->buffer;
69
7ed47b7d NB	70	if (!ctx->gf128)
	71	return -ENOKEY;
	72
2cdc6899 YH	73	if (dctx->bytes) {
	74	int n = min(srclen, dctx->bytes);
	75	u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
	76
	77	dctx->bytes -= n;
	78	srclen -= n;
	79
	80	while (n--)
	81	pos++ ^= src++;
	82
	83	if (!dctx->bytes)
	84	gf128mul_4k_lle((be128 *)dst, ctx->gf128);
	85	}
	86
	87	while (srclen >= GHASH_BLOCK_SIZE) {
	88	crypto_xor(dst, src, GHASH_BLOCK_SIZE);
	89	gf128mul_4k_lle((be128 *)dst, ctx->gf128);
	90	src += GHASH_BLOCK_SIZE;
	91	srclen -= GHASH_BLOCK_SIZE;
	92	}
	93
	94	if (srclen) {
	95	dctx->bytes = GHASH_BLOCK_SIZE - srclen;
	96	while (srclen--)
	97	dst++ ^= src++;
	98	}
	99
	100	return 0;
	101	}
	102
	103	static void ghash_flush(struct ghash_ctx ctx, struct ghash_desc_ctx dctx)
	104	{
	105	u8 *dst = dctx->buffer;
	106
	107	if (dctx->bytes) {
	108	u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
	109
	110	while (dctx->bytes--)
	111	*tmp++ ^= 0;
	112
	113	gf128mul_4k_lle((be128 *)dst, ctx->gf128);
	114	}
	115
	116	dctx->bytes = 0;
	117	}
	118
	119	static int ghash_final(struct shash_desc desc, u8 dst)
	120	{
	121	struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
	122	struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
	123	u8 *buf = dctx->buffer;
	124
7ed47b7d NB	125	if (!ctx->gf128)
	126	return -ENOKEY;
	127
2cdc6899 YH	128	ghash_flush(ctx, dctx);
	129	memcpy(dst, buf, GHASH_BLOCK_SIZE);
	130
	131	return 0;
	132	}
	133
	134	static void ghash_exit_tfm(struct crypto_tfm *tfm)
	135	{
	136	struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
	137	if (ctx->gf128)
	138	gf128mul_free_4k(ctx->gf128);
	139	}
	140
	141	static struct shash_alg ghash_alg = {
	142	.digestsize = GHASH_DIGEST_SIZE,
	143	.init = ghash_init,
	144	.update = ghash_update,
	145	.final = ghash_final,
	146	.setkey = ghash_setkey,
	147	.descsize = sizeof(struct ghash_desc_ctx),
	148	.base = {
	149	.cra_name = "ghash",
	150	.cra_driver_name = "ghash-generic",
	151	.cra_priority = 100,
	152	.cra_flags = CRYPTO_ALG_TYPE_SHASH,
	153	.cra_blocksize = GHASH_BLOCK_SIZE,
	154	.cra_ctxsize = sizeof(struct ghash_ctx),
	155	.cra_module = THIS_MODULE,
2cdc6899 YH	156	.cra_exit = ghash_exit_tfm,
	157	},
	158	};
	159
	160	static int __init ghash_mod_init(void)
	161	{
	162	return crypto_register_shash(&ghash_alg);
	163	}
	164
	165	static void __exit ghash_mod_exit(void)
	166	{
	167	crypto_unregister_shash(&ghash_alg);
	168	}
	169
	170	module_init(ghash_mod_init);
	171	module_exit(ghash_mod_exit);
	172
	173	MODULE_LICENSE("GPL");
	174	MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
	175	MODULE_ALIAS("ghash");