// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * ARIA Cipher Algorithm.
 *
 * Documentation of ARIA can be found in RFC 5794.
 * Copyright (c) 2022 Taehee Yoo <ap420073@gmail.com>
 *
 * Information for ARIA
 *     http://210.104.33.10/ARIA/index-e.html (English)
 *     http://seed.kisa.or.kr/ (Korean)
 *
 * Public domain version is distributed above.
 */

#include <crypto/aria.h>

static void aria_set_encrypt_key(struct aria_ctx *ctx, const u8 *in_key,
				 unsigned int key_len)
{
	const __be32 *key = (const __be32 *)in_key;
	u32 w0[4], w1[4], w2[4], w3[4];
	u32 reg0, reg1, reg2, reg3;
	const u32 *ck;
	int rkidx = 0;

	ck = &key_rc[(key_len - 16) / 8][0];

	w0[0] = be32_to_cpu(key[0]);
	w0[1] = be32_to_cpu(key[1]);
	w0[2] = be32_to_cpu(key[2]);
	w0[3] = be32_to_cpu(key[3]);

	reg0 = w0[0] ^ ck[0];
	reg1 = w0[1] ^ ck[1];
	reg2 = w0[2] ^ ck[2];
	reg3 = w0[3] ^ ck[3];

	aria_subst_diff_odd(&reg0, &reg1, &reg2, &reg3);

	if (key_len > 16) {
		w1[0] = be32_to_cpu(key[4]);
		w1[1] = be32_to_cpu(key[5]);
		if (key_len > 24) {
			w1[2] = be32_to_cpu(key[6]);
			w1[3] = be32_to_cpu(key[7]);
		} else {
			w1[2] = 0;
			w1[3] = 0;
		}
	} else {
		w1[0] = 0;
		w1[1] = 0;
		w1[2] = 0;
		w1[3] = 0;
	}

	w1[0] ^= reg0;
	w1[1] ^= reg1;
	w1[2] ^= reg2;
	w1[3] ^= reg3;

	reg0 = w1[0];
	reg1 = w1[1];
	reg2 = w1[2];
	reg3 = w1[3];

	reg0 ^= ck[4];
	reg1 ^= ck[5];
	reg2 ^= ck[6];
	reg3 ^= ck[7];

	aria_subst_diff_even(&reg0, &reg1, &reg2, &reg3);

	reg0 ^= w0[0];
	reg1 ^= w0[1];
	reg2 ^= w0[2];
	reg3 ^= w0[3];

	w2[0] = reg0;
	w2[1] = reg1;
	w2[2] = reg2;
	w2[3] = reg3;

	reg0 ^= ck[8];
	reg1 ^= ck[9];
	reg2 ^= ck[10];
	reg3 ^= ck[11];

	aria_subst_diff_odd(&reg0, &reg1, &reg2, &reg3);

	w3[0] = reg0 ^ w1[0];
	w3[1] = reg1 ^ w1[1];
	w3[2] = reg2 ^ w1[2];
	w3[3] = reg3 ^ w1[3];

	aria_gsrk(ctx->enc_key[rkidx], w0, w1, 19);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w1, w2, 19);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w2, w3, 19);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w3, w0, 19);

	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w0, w1, 31);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w1, w2, 31);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w2, w3, 31);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w3, w0, 31);

	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w0, w1, 67);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w1, w2, 67);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w2, w3, 67);
	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w3, w0, 67);

	rkidx++;
	aria_gsrk(ctx->enc_key[rkidx], w0, w1, 97);
	if (key_len > 16) {
		rkidx++;
		aria_gsrk(ctx->enc_key[rkidx], w1, w2, 97);
		rkidx++;
		aria_gsrk(ctx->enc_key[rkidx], w2, w3, 97);

		if (key_len > 24) {
			rkidx++;
			aria_gsrk(ctx->enc_key[rkidx], w3, w0, 97);

			rkidx++;
			aria_gsrk(ctx->enc_key[rkidx], w0, w1, 109);
		}
	}
}

static void aria_set_decrypt_key(struct aria_ctx *ctx)
{
	int i;

	for (i = 0; i < 4; i++) {
		ctx->dec_key[0][i] = ctx->enc_key[ctx->rounds][i];
		ctx->dec_key[ctx->rounds][i] = ctx->enc_key[0][i];
	}

	for (i = 1; i < ctx->rounds; i++) {
		ctx->dec_key[i][0] = aria_m(ctx->enc_key[ctx->rounds - i][0]);
		ctx->dec_key[i][1] = aria_m(ctx->enc_key[ctx->rounds - i][1]);
		ctx->dec_key[i][2] = aria_m(ctx->enc_key[ctx->rounds - i][2]);
		ctx->dec_key[i][3] = aria_m(ctx->enc_key[ctx->rounds - i][3]);

		aria_diff_word(&ctx->dec_key[i][0], &ctx->dec_key[i][1],
			       &ctx->dec_key[i][2], &ctx->dec_key[i][3]);
		aria_diff_byte(&ctx->dec_key[i][1],
			       &ctx->dec_key[i][2], &ctx->dec_key[i][3]);
		aria_diff_word(&ctx->dec_key[i][0], &ctx->dec_key[i][1],
			       &ctx->dec_key[i][2], &ctx->dec_key[i][3]);
	}
}

static int aria_set_key(struct crypto_tfm *tfm, const u8 *in_key,
			unsigned int key_len)
{
	struct aria_ctx *ctx = crypto_tfm_ctx(tfm);

	if (key_len != 16 && key_len != 24 && key_len != 32)
		return -EINVAL;

	ctx->key_length = key_len;
	ctx->rounds = (key_len + 32) / 4;

	aria_set_encrypt_key(ctx, in_key, key_len);
	aria_set_decrypt_key(ctx);

	return 0;
}

static void __aria_crypt(struct aria_ctx *ctx, u8 *out, const u8 *in,
			 u32 key[][ARIA_RD_KEY_WORDS])
{
	const __be32 *src = (const __be32 *)in;
	__be32 *dst = (__be32 *)out;
	u32 reg0, reg1, reg2, reg3;
	int rounds, rkidx = 0;

	rounds = ctx->rounds;

	reg0 = be32_to_cpu(src[0]);
	reg1 = be32_to_cpu(src[1]);
	reg2 = be32_to_cpu(src[2]);
	reg3 = be32_to_cpu(src[3]);

	aria_add_round_key(key[rkidx], &reg0, &reg1, &reg2, &reg3);
	rkidx++;

	aria_subst_diff_odd(&reg0, &reg1, &reg2, &reg3);
	aria_add_round_key(key[rkidx], &reg0, &reg1, &reg2, &reg3);
	rkidx++;

	while ((rounds -= 2) > 0) {
		aria_subst_diff_even(&reg0, &reg1, &reg2, &reg3);
		aria_add_round_key(key[rkidx], &reg0, &reg1, &reg2, &reg3);
		rkidx++;

		aria_subst_diff_odd(&reg0, &reg1, &reg2, &reg3);
		aria_add_round_key(key[rkidx], &reg0, &reg1, &reg2, &reg3);
		rkidx++;
	}

	reg0 = key[rkidx][0] ^ make_u32((u8)(x1[get_u8(reg0, 0)]),
					(u8)(x2[get_u8(reg0, 1)] >> 8),
					(u8)(s1[get_u8(reg0, 2)]),
					(u8)(s2[get_u8(reg0, 3)]));
	reg1 = key[rkidx][1] ^ make_u32((u8)(x1[get_u8(reg1, 0)]),
					(u8)(x2[get_u8(reg1, 1)] >> 8),
					(u8)(s1[get_u8(reg1, 2)]),
					(u8)(s2[get_u8(reg1, 3)]));
	reg2 = key[rkidx][2] ^ make_u32((u8)(x1[get_u8(reg2, 0)]),
					(u8)(x2[get_u8(reg2, 1)] >> 8),
					(u8)(s1[get_u8(reg2, 2)]),
					(u8)(s2[get_u8(reg2, 3)]));
	reg3 = key[rkidx][3] ^ make_u32((u8)(x1[get_u8(reg3, 0)]),
					(u8)(x2[get_u8(reg3, 1)] >> 8),
					(u8)(s1[get_u8(reg3, 2)]),
					(u8)(s2[get_u8(reg3, 3)]));

	dst[0] = cpu_to_be32(reg0);
	dst[1] = cpu_to_be32(reg1);
	dst[2] = cpu_to_be32(reg2);
	dst[3] = cpu_to_be32(reg3);
}

static void aria_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct aria_ctx *ctx = crypto_tfm_ctx(tfm);

	__aria_crypt(ctx, out, in, ctx->enc_key);
}

static void aria_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct aria_ctx *ctx = crypto_tfm_ctx(tfm);

	__aria_crypt(ctx, out, in, ctx->dec_key);
}

static struct crypto_alg aria_alg = {
	.cra_name		=	"aria",
	.cra_driver_name	=	"aria-generic",
	.cra_priority		=	100,
	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize		=	ARIA_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct aria_ctx),
	.cra_alignmask		=	3,
	.cra_module		=	THIS_MODULE,
	.cra_u			=	{
		.cipher = {
			.cia_min_keysize	=	ARIA_MIN_KEY_SIZE,
			.cia_max_keysize	=	ARIA_MAX_KEY_SIZE,
			.cia_setkey		=	aria_set_key,
			.cia_encrypt		=	aria_encrypt,
			.cia_decrypt		=	aria_decrypt
		}
	}
};

static int __init aria_init(void)
{
	return crypto_register_alg(&aria_alg);
}

static void __exit aria_fini(void)
{
	crypto_unregister_alg(&aria_alg);
}

subsys_initcall(aria_init);
module_exit(aria_fini);

MODULE_DESCRIPTION("ARIA Cipher Algorithm");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Taehee Yoo <ap420073@gmail.com>");
MODULE_ALIAS_CRYPTO("aria");