// SPDX-License-Identifier: BSD-2-Clause
/*
 * Copyright Copyright (c) 2019 Huawei Technologies Co., Ltd
 */
/*
 * SM4 Encryption algorithm (SMS4 algorithm)
 * GM/T 0002-2012 Chinese National Standard ref:http://www.oscca.gov.cn/
 * thanks to Xyssl
 * thnaks and refers to http://hi.baidu.com/numax/blog/item/80addfefddfb93e4cf1b3e61.html
 * author:goldboar
 * email:goldboar@163.com
 * 2012-4-20
 */

#include "sm4.h"
#include <assert.h>
#include <string.h>

#define GET_UINT32_BE(n, b, i)				\
	do {						\
		(n) = ((uint32_t)(b)[(i)] << 24)     |	\
		      ((uint32_t)(b)[(i) + 1] << 16) |	\
		      ((uint32_t)(b)[(i) + 2] <<  8) |	\
		      ((uint32_t)(b)[(i) + 3]);		\
	} while (0)

#define PUT_UINT32_BE(n, b, i)				\
	do {						\
		(b)[(i)] = (uint8_t)((n) >> 24);	\
		(b)[(i) + 1] = (uint8_t)((n) >> 16);	\
		(b)[(i) + 2] = (uint8_t)((n) >>  8);	\
		(b)[(i) + 3] = (uint8_t)((n));		\
	} while (0)

#define SHL(x, n)	(((x) & 0xFFFFFFFF) << (n))
#define ROTL(x, n)	(SHL((x), (n)) | ((x) >> (32 - (n))))

#define SWAP(a, b)	{ uint32_t t = a; a = b; b = t; t = 0; }

/*
 * Expanded SM4 S-boxes
 */
static const uint8_t SboxTable[16][16] =  {
	{0xd6, 0x90, 0xe9, 0xfe, 0xcc, 0xe1, 0x3d, 0xb7,
	 0x16, 0xb6, 0x14, 0xc2, 0x28, 0xfb, 0x2c, 0x05},
	{0x2b, 0x67, 0x9a, 0x76, 0x2a, 0xbe, 0x04, 0xc3,
	 0xaa, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99},
	{0x9c, 0x42, 0x50, 0xf4, 0x91, 0xef, 0x98, 0x7a,
	 0x33, 0x54, 0x0b, 0x43, 0xed, 0xcf, 0xac, 0x62},
	{0xe4, 0xb3, 0x1c, 0xa9, 0xc9, 0x08, 0xe8, 0x95,
	 0x80, 0xdf, 0x94, 0xfa, 0x75, 0x8f, 0x3f, 0xa6},
	{0x47, 0x07, 0xa7, 0xfc, 0xf3, 0x73, 0x17, 0xba,
	 0x83, 0x59, 0x3c, 0x19, 0xe6, 0x85, 0x4f, 0xa8},
	{0x68, 0x6b, 0x81, 0xb2, 0x71, 0x64, 0xda, 0x8b,
	 0xf8, 0xeb, 0x0f, 0x4b, 0x70, 0x56, 0x9d, 0x35},
	{0x1e, 0x24, 0x0e, 0x5e, 0x63, 0x58, 0xd1, 0xa2,
	 0x25, 0x22, 0x7c, 0x3b, 0x01, 0x21, 0x78, 0x87},
	{0xd4, 0x00, 0x46, 0x57, 0x9f, 0xd3, 0x27, 0x52,
	 0x4c, 0x36, 0x02, 0xe7, 0xa0, 0xc4, 0xc8, 0x9e},
	{0xea, 0xbf, 0x8a, 0xd2, 0x40, 0xc7, 0x38, 0xb5,
	 0xa3, 0xf7, 0xf2, 0xce, 0xf9, 0x61, 0x15, 0xa1},
	{0xe0, 0xae, 0x5d, 0xa4, 0x9b, 0x34, 0x1a, 0x55,
	 0xad, 0x93, 0x32, 0x30, 0xf5, 0x8c, 0xb1, 0xe3},
	{0x1d, 0xf6, 0xe2, 0x2e, 0x82, 0x66, 0xca, 0x60,
	 0xc0, 0x29, 0x23, 0xab, 0x0d, 0x53, 0x4e, 0x6f},
	{0xd5, 0xdb, 0x37, 0x45, 0xde, 0xfd, 0x8e, 0x2f,
	 0x03, 0xff, 0x6a, 0x72, 0x6d, 0x6c, 0x5b, 0x51},
	{0x8d, 0x1b, 0xaf, 0x92, 0xbb, 0xdd, 0xbc, 0x7f,
	 0x11, 0xd9, 0x5c, 0x41, 0x1f, 0x10, 0x5a, 0xd8},
	{0x0a, 0xc1, 0x31, 0x88, 0xa5, 0xcd, 0x7b, 0xbd,
	 0x2d, 0x74, 0xd0, 0x12, 0xb8, 0xe5, 0xb4, 0xb0},
	{0x89, 0x69, 0x97, 0x4a, 0x0c, 0x96, 0x77, 0x7e,
	 0x65, 0xb9, 0xf1, 0x09, 0xc5, 0x6e, 0xc6, 0x84},
	{0x18, 0xf0, 0x7d, 0xec, 0x3a, 0xdc, 0x4d, 0x20,
	 0x79, 0xee, 0x5f, 0x3e, 0xd7, 0xcb, 0x39, 0x48}
};

/* System parameter */
static const uint32_t FK[4] = {
	0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
};

/* Fixed parameter */
static const uint32_t CK[32] = {
	0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
	0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
	0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
	0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
	0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
	0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
	0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
	0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
};

static uint8_t sm4Sbox(uint8_t inch)
{
	uint8_t *tab = (uint8_t *)SboxTable;

	return tab[inch];
}

static uint32_t sm4Lt(uint32_t ka)
{
	uint32_t bb = 0;
	uint8_t a[4];
	uint8_t b[4];

	PUT_UINT32_BE(ka, a, 0);
	b[0] = sm4Sbox(a[0]);
	b[1] = sm4Sbox(a[1]);
	b[2] = sm4Sbox(a[2]);
	b[3] = sm4Sbox(a[3]);
	GET_UINT32_BE(bb, b, 0);

	return bb ^ ROTL(bb, 2) ^ ROTL(bb, 10) ^ ROTL(bb, 18) ^ ROTL(bb, 24);
}

static uint32_t sm4F(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
		     uint32_t rk)
{
	return x0 ^ sm4Lt(x1 ^ x2 ^ x3 ^ rk);
}

static uint32_t sm4CalciRK(uint32_t ka)
{
	uint32_t bb = 0;
	uint8_t a[4];
	uint8_t b[4];

	PUT_UINT32_BE(ka, a, 0);
	b[0] = sm4Sbox(a[0]);
	b[1] = sm4Sbox(a[1]);
	b[2] = sm4Sbox(a[2]);
	b[3] = sm4Sbox(a[3]);
	GET_UINT32_BE(bb, b, 0);

	return bb ^ ROTL(bb, 13) ^ ROTL(bb, 23);
}

static void sm4_setkey(uint32_t SK[32], const uint8_t key[16])
{
	uint32_t MK[4];
	uint32_t k[36];
	uint32_t i = 0;

	GET_UINT32_BE(MK[0], key, 0);
	GET_UINT32_BE(MK[1], key, 4);
	GET_UINT32_BE(MK[2], key, 8);
	GET_UINT32_BE(MK[3], key, 12);

	k[0] = MK[0] ^ FK[0];
	k[1] = MK[1] ^ FK[1];
	k[2] = MK[2] ^ FK[2];
	k[3] = MK[3] ^ FK[3];

	for (i = 0; i < 32; i++) {
		k[i + 4] = k[i] ^ sm4CalciRK(k[i + 1] ^ k[i + 2] ^ k[i + 3] ^
					     CK[i]);
		SK[i] = k[i + 4];
	}
}

static void sm4_one_round(uint32_t sk[32], const uint8_t input[16],
			  uint8_t output[16])
{
	uint32_t i = 0;
	uint32_t ulbuf[36];

	memset(ulbuf, 0, sizeof(ulbuf));

	GET_UINT32_BE(ulbuf[0], input, 0);
	GET_UINT32_BE(ulbuf[1], input, 4);
	GET_UINT32_BE(ulbuf[2], input, 8);
	GET_UINT32_BE(ulbuf[3], input, 12);

	for (i = 0; i < 32; i++)
		ulbuf[i + 4] = sm4F(ulbuf[i], ulbuf[i + 1], ulbuf[i + 2],
				    ulbuf[i + 3], sk[i]);

	PUT_UINT32_BE(ulbuf[35], output, 0);
	PUT_UINT32_BE(ulbuf[34], output, 4);
	PUT_UINT32_BE(ulbuf[33], output, 8);
	PUT_UINT32_BE(ulbuf[32], output, 12);
}

void sm4_setkey_enc(struct sm4_context *ctx, const uint8_t key[16])
{
	ctx->mode = SM4_ENCRYPT;
	sm4_setkey(ctx->sk, key);
}

void sm4_setkey_dec(struct sm4_context *ctx, const uint8_t key[16])
{
	int i;

	ctx->mode = SM4_DECRYPT;
	sm4_setkey(ctx->sk, key);

	for (i = 0; i < 16; i++)
		SWAP(ctx->sk[i], ctx->sk[31 - i]);
}

void sm4_crypt_ecb(struct sm4_context *ctx, size_t length, const uint8_t *input,
		   uint8_t *output)
{
	assert(!(length % 16));

	while (length > 0) {
		sm4_one_round(ctx->sk, input, output);
		input  += 16;
		output += 16;
		length -= 16;
	}
}

void sm4_crypt_cbc(struct sm4_context *ctx, size_t length, uint8_t iv[16],
		   const uint8_t *input, uint8_t *output)
{
	int i;
	uint8_t temp[16];

	assert(!(length % 16));

	if (ctx->mode == SM4_ENCRYPT) {
		while (length > 0) {
			for (i = 0; i < 16; i++)
				output[i] = (uint8_t)(input[i] ^ iv[i]);
			sm4_one_round(ctx->sk, output, output);
			memcpy(iv, output, 16);
			input  += 16;
			output += 16;
			length -= 16;
		}
	} else {
		/* SM4_DECRYPT */
		while (length > 0) {
			memcpy(temp, input, 16);
			sm4_one_round(ctx->sk, input, output);
			for (i = 0; i < 16; i++)
				output[i] = (uint8_t)(output[i] ^ iv[i]);
			memcpy(iv, temp, 16);
			input  += 16;
			output += 16;
			length -= 16;
		}
	}
}

void sm4_crypt_ctr(struct sm4_context *ctx, size_t length, uint8_t ctr[16],
		   const uint8_t *input, uint8_t *output)
{
	int i;
	uint8_t temp[16];

	assert(!(length % 16));

	while (length > 0) {
		memcpy(temp, ctr, 16);
		sm4_one_round(ctx->sk, ctr, ctr);
		for (i = 0; i < 16; i++)
			output[i] = (uint8_t)(input[i] ^ ctr[i]);
		memcpy(ctr, temp, 16);
		for (i = 16; i > 0; i--)
			if (++ctr[i - 1])
				break;
		input  += 16;
		output += 16;
		length -= 16;
	}
}

static void xts_multi(unsigned char *in, unsigned char *out)
{
	uint8_t tt = 0;
	uint8_t t = 0;
	int i = 0;

	for (i = 0; i < 16; i++) {
		tt = in[i] >> 7;
		out[i] = ((in[i] << 1) | t) & 0xFF;
		t = tt;
	}

	out[0] ^= (0x87 & (0 - tt));
}

static void xor_128(const uint8_t a[16], const uint8_t b[16], uint8_t c[16])
{
	int i = 0;

	for (i = 0; i < 16; i++)
		c[i] = a[i] ^ b[i];
}

void sm4_crypt_xts(struct sm4_context *ctx, struct sm4_context *ctx_ek,
		   struct sm4_context *ctx_dk, size_t len, uint8_t *iv,
		   const uint8_t *input, uint8_t *output)
{
	uint8_t tweak[16] = { };
	uint8_t tweak1[16] = { };
	uint8_t ct[16] = { };
	size_t i = 0;

	assert(len >= 16);

	sm4_one_round(ctx_ek->sk, iv, tweak);

	if (ctx->mode == SM4_DECRYPT && (len % 16))
		len -= 16;

	while (len >= 16) {
		xor_128(input, tweak, ct);
		sm4_one_round(ctx->sk, ct, ct);
		xor_128(ct, tweak, output);

		xts_multi(tweak, tweak);
		len -= 16;
		if (len == 0) {
			sm4_one_round(ctx_dk->sk, tweak, iv);
			return;
		}
		input += 16;
		output += 16;
	}

	if (ctx->mode == SM4_ENCRYPT) {
		memcpy(ct, output - 16, 16);
		for (i = 0; i < len; i++) {
			output[i] = ct[i];
			ct[i] = input[i];
		}

		xor_128(ct, tweak, ct);
		sm4_one_round(ctx->sk, ct, ct);
		xor_128(ct, tweak, ct);
		memcpy(output - 16, ct, 16);
	} else {
		xts_multi(tweak, tweak1);
		xor_128(input, tweak1, ct);
		sm4_one_round(ctx->sk, ct, ct);
		xor_128(ct, tweak1, ct);

		for (i = 0; i < len; ++i) {
			output[16 + i] = ct[i];
			ct[i] = input[16 + i];
		}
		xor_128(ct, tweak, ct);
		sm4_one_round(ctx->sk, ct, ct);
		xor_128(ct, tweak, output);
	}
}
