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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/crypto/blowfish_generic.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 * Cryptographic API.

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 *

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 * Blowfish Cipher Algorithm, by Bruce Schneier.

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 * http://www.counterpane.com/blowfish.html

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 *

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 * Adapted from Kerneli implementation.

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 *

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 * Copyright (c) Herbert Valerio Riedel <[email protected]>

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 * Copyright (c) Kyle McMartin <[email protected]>

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 * Copyright (c) 2002 James Morris <[email protected]>

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 */

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#include <crypto/algapi.h>

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#include <linux/init.h>

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#include <linux/module.h>

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#include <linux/mm.h>

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#include <linux/unaligned.h>

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#include <linux/types.h>

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#include <crypto/blowfish.h>

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/*

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 * Round loop unrolling macros, S is a pointer to a S-Box array

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 * organized in 4 unsigned longs at a row.

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 */

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#define GET32_3(x) (((x) & 0xff))

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#define GET32_2(x) (((x) >> (8)) & (0xff))

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#define GET32_1(x) (((x) >> (16)) & (0xff))

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#define GET32_0(x) (((x) >> (24)) & (0xff))

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#define bf_F(x) (((S[GET32_0(x)] + S[256 + GET32_1(x)]) ^ \

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		S[512 + GET32_2(x)]) + S[768 + GET32_3(x)])

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#define ROUND(a, b, n) ({ b ^= P[n]; a ^= bf_F(b); })

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static void bf_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)

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{

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	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);

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	const u32 *P = ctx->p;

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	const u32 *S = ctx->s;

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	u32 yl = get_unaligned_be32(src);

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	u32 yr = get_unaligned_be32(src + 4);

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	ROUND(yr, yl, 0);

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	ROUND(yl, yr, 1);

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	ROUND(yr, yl, 2);

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	ROUND(yl, yr, 3);

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	ROUND(yr, yl, 4);

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	ROUND(yl, yr, 5);

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	ROUND(yr, yl, 6);

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	ROUND(yl, yr, 7);

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	ROUND(yr, yl, 8);

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	ROUND(yl, yr, 9);

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	ROUND(yr, yl, 10);

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	ROUND(yl, yr, 11);

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	ROUND(yr, yl, 12);

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	ROUND(yl, yr, 13);

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	ROUND(yr, yl, 14);

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	ROUND(yl, yr, 15);

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	yl ^= P[16];

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	yr ^= P[17];

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	put_unaligned_be32(yr, dst);

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	put_unaligned_be32(yl, dst + 4);

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}

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static void bf_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)

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{

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	struct bf_ctx *ctx = crypto_tfm_ctx(tfm);

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	const u32 *P = ctx->p;

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	const u32 *S = ctx->s;

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	u32 yl = get_unaligned_be32(src);

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	u32 yr = get_unaligned_be32(src + 4);

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	ROUND(yr, yl, 17);

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	ROUND(yl, yr, 16);

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	ROUND(yr, yl, 15);

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	ROUND(yl, yr, 14);

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	ROUND(yr, yl, 13);

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	ROUND(yl, yr, 12);

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	ROUND(yr, yl, 11);

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	ROUND(yl, yr, 10);

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	ROUND(yr, yl, 9);

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	ROUND(yl, yr, 8);

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	ROUND(yr, yl, 7);

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	ROUND(yl, yr, 6);

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	ROUND(yr, yl, 5);

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	ROUND(yl, yr, 4);

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	ROUND(yr, yl, 3);

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	ROUND(yl, yr, 2);

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	yl ^= P[1];

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	yr ^= P[0];

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	put_unaligned_be32(yr, dst);

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	put_unaligned_be32(yl, dst + 4);

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}

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static struct crypto_alg alg = {

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	.cra_name		=	"blowfish",

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	.cra_driver_name	=	"blowfish-generic",

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	.cra_priority		=	100,

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	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,

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	.cra_blocksize		=	BF_BLOCK_SIZE,

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	.cra_ctxsize		=	sizeof(struct bf_ctx),

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	.cra_module		=	THIS_MODULE,

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	.cra_u			=	{ .cipher = {

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	.cia_min_keysize	=	BF_MIN_KEY_SIZE,

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	.cia_max_keysize	=	BF_MAX_KEY_SIZE,

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	.cia_setkey		=	blowfish_setkey,

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	.cia_encrypt		=	bf_encrypt,

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	.cia_decrypt		=	bf_decrypt } }

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};

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static int __init blowfish_mod_init(void)

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{

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	return crypto_register_alg(&alg);

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}

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static void __exit blowfish_mod_fini(void)

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{

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	crypto_unregister_alg(&alg);

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}

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module_init(blowfish_mod_init);

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module_exit(blowfish_mod_fini);

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MODULE_LICENSE("GPL");

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MODULE_DESCRIPTION("Blowfish Cipher Algorithm");

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MODULE_ALIAS_CRYPTO("blowfish");

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MODULE_ALIAS_CRYPTO("blowfish-generic");

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