/* 
 * This file is part of the Pico CCID distribution (https://github.com/polhenarejos/pico-ccid).
 * Copyright (c) 2022 Pol Henarejos.
 * 
 * This program is free software: you can redistribute it and/or modify  
 * it under the terms of the GNU General Public License as published by  
 * the Free Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#include <pico/unique_id.h>
#include "mbedtls/md.h"
#include "mbedtls/sha256.h"
#include "mbedtls/aes.h"
#include "crypto_utils.h"
#include "ccid2040.h"

void double_hash_pin(const uint8_t *pin, size_t len, uint8_t output[32]) {
    uint8_t o1[32];
    hash_multi(pin, len, o1);
    for (int i = 0; i < sizeof(o1); i++)
        o1[i] ^= pin[i%len];
    hash_multi(o1, sizeof(o1), output);
}

void hash_multi(const uint8_t *input, size_t len, uint8_t output[32]) {
    mbedtls_sha256_context ctx;
    mbedtls_sha256_init(&ctx);
    int iters = 256;
    pico_unique_board_id_t unique_id;
    
    pico_get_unique_board_id(&unique_id);
    
    mbedtls_sha256_starts (&ctx, 0);
    mbedtls_sha256_update (&ctx, unique_id.id, sizeof(unique_id.id));
    
    while (iters > len)
    {
        mbedtls_sha256_update (&ctx, input, len);
        iters -= len;
    }
    if (iters > 0) // remaining iterations
        mbedtls_sha256_update (&ctx, input, iters);
    mbedtls_sha256_finish (&ctx, output);
    mbedtls_sha256_free (&ctx);
}

void hash256(const uint8_t *input, size_t len, uint8_t output[32]) {
    mbedtls_sha256_context ctx;
    mbedtls_sha256_init(&ctx);
    
    mbedtls_sha256_starts (&ctx, 0);
    mbedtls_sha256_update (&ctx, input, len);

    mbedtls_sha256_finish (&ctx, output);
    mbedtls_sha256_free (&ctx);
}

void generic_hash(mbedtls_md_type_t md, const uint8_t *input, size_t len, uint8_t *output) {
    mbedtls_md_context_t ctx;
    mbedtls_md_init(&ctx);
    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(md);
    mbedtls_md_setup(&ctx, md_info, 0);
    mbedtls_md_starts(&ctx);
    mbedtls_md_update(&ctx, input, len);
    mbedtls_md_finish(&ctx, output);
    mbedtls_md_free(&ctx);   
}

int aes_encrypt(const uint8_t *key, const uint8_t *iv, int key_size, int mode, uint8_t *data, int len) {
    mbedtls_aes_context aes;
    mbedtls_aes_init(&aes);
    uint8_t tmp_iv[IV_SIZE];
    size_t iv_offset = 0;
    memset(tmp_iv, 0, IV_SIZE);
    if (iv)
        memcpy(tmp_iv, iv, IV_SIZE);
    int r = mbedtls_aes_setkey_enc(&aes, key, key_size);
    if (r != 0)
        return CCID_EXEC_ERROR;
    if (mode == HSM_AES_MODE_CBC)
        return mbedtls_aes_crypt_cbc(&aes, MBEDTLS_AES_ENCRYPT, len, tmp_iv, data, data);
    return mbedtls_aes_crypt_cfb128(&aes, MBEDTLS_AES_ENCRYPT, len, &iv_offset, tmp_iv, data, data);
}

int aes_decrypt(const uint8_t *key, const uint8_t *iv, int key_size, int mode, uint8_t *data, int len) {
    mbedtls_aes_context aes;
    mbedtls_aes_init(&aes);
    uint8_t tmp_iv[IV_SIZE];
    size_t iv_offset = 0;
    memset(tmp_iv, 0, IV_SIZE);
    if (iv)
        memcpy(tmp_iv, iv, IV_SIZE);
    int r = mbedtls_aes_setkey_dec(&aes, key, key_size);
    if (r != 0)
        return CCID_EXEC_ERROR;
    if (mode == HSM_AES_MODE_CBC)
        return mbedtls_aes_crypt_cbc(&aes, MBEDTLS_AES_DECRYPT, len, tmp_iv, data, data);
    r = mbedtls_aes_setkey_enc(&aes, key, key_size); //CFB requires set_enc instead set_dec
    return mbedtls_aes_crypt_cfb128(&aes, MBEDTLS_AES_DECRYPT, len, &iv_offset, tmp_iv, data, data);
}

int aes_encrypt_cfb_256(const uint8_t *key, const uint8_t *iv, uint8_t *data, int len) {
    return aes_encrypt(key, iv, 256, HSM_AES_MODE_CFB, data, len);
}
int aes_decrypt_cfb_256(const uint8_t *key, const uint8_t *iv, uint8_t *data, int len) {
    return aes_decrypt(key, iv, 256, HSM_AES_MODE_CFB, data, len);
}

struct lv_data {
    unsigned char *value;
    uint8_t len;
};

struct ec_curve_mbed_id {
    struct lv_data curve;
    mbedtls_ecp_group_id id;
};
struct ec_curve_mbed_id ec_curves_mbed[] = {
    {   { (unsigned char *) "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFE\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 24}, MBEDTLS_ECP_DP_SECP192R1 },
    {   { (unsigned char *) "\xFF\xFF\xFF\xFF\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 32}, MBEDTLS_ECP_DP_SECP256R1 },
    {   { (unsigned char *) "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFE\xFF\xFF\xFF\xFF\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF\xFF\xFF", 48}, MBEDTLS_ECP_DP_SECP384R1 },
    {   { (unsigned char *) "\x01\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 66}, MBEDTLS_ECP_DP_SECP521R1 },
    {   { (unsigned char *) "\xA9\xFB\x57\xDB\xA1\xEE\xA9\xBC\x3E\x66\x0A\x90\x9D\x83\x8D\x72\x6E\x3B\xF6\x23\xD5\x26\x20\x28\x20\x13\x48\x1D\x1F\x6E\x53\x77", 32}, MBEDTLS_ECP_DP_BP256R1 },
    {   { (unsigned char *) "\x8C\xB9\x1E\x82\xA3\x38\x6D\x28\x0F\x5D\x6F\x7E\x50\xE6\x41\xDF\x15\x2F\x71\x09\xED\x54\x56\xB4\x12\xB1\xDA\x19\x7F\xB7\x11\x23\xAC\xD3\xA7\x29\x90\x1D\x1A\x71\x87\x47\x00\x13\x31\x07\xEC\x53", 48}, MBEDTLS_ECP_DP_BP384R1 },
    {   { (unsigned char *) "\xAA\xDD\x9D\xB8\xDB\xE9\xC4\x8B\x3F\xD4\xE6\xAE\x33\xC9\xFC\x07\xCB\x30\x8D\xB3\xB3\xC9\xD2\x0E\xD6\x63\x9C\xCA\x70\x33\x08\x71\x7D\x4D\x9B\x00\x9B\xC6\x68\x42\xAE\xCD\xA1\x2A\xE6\xA3\x80\xE6\x28\x81\xFF\x2F\x2D\x82\xC6\x85\x28\xAA\x60\x56\x58\x3A\x48\xF3", 64}, MBEDTLS_ECP_DP_BP512R1 },
    {   { (unsigned char *) "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFE\xFF\xFF\xEE\x37", 24}, MBEDTLS_ECP_DP_SECP192K1 },
    {   { (unsigned char *) "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFE\xFF\xFF\xFC\x2F", 32}, MBEDTLS_ECP_DP_SECP256K1 },
    {   { NULL, 0 }, MBEDTLS_ECP_DP_NONE }
};

mbedtls_ecp_group_id ec_get_curve_from_prime(const uint8_t *prime, size_t prime_len) {
    for (struct ec_curve_mbed_id *ec = ec_curves_mbed; ec->id != MBEDTLS_ECP_DP_NONE; ec++) {
        if (prime_len == ec->curve.len && memcmp(prime, ec->curve.value, prime_len) == 0) {
            return ec->id;
        }
    }
    return MBEDTLS_ECP_DP_NONE;
}