/* test_ecc_utils.c - TinyCrypt common functions for ECC tests */

/*  Copyright (c) 2014, Kenneth MacKay
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
 *  * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.*/

/*
    Copyright (C) 2017 by Intel Corporation, All Rights Reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:

      - Redistributions of source code must retain the above copyright notice,
       this list of conditions and the following disclaimer.

      - Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

      - Neither the name of Intel Corporation nor the names of its contributors
      may be used to endorse or promote products derived from this software
      without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.

    test_ecc_utils.c -- Implementation of some common functions for ECC tests.

*/

#include <test_ecc_utils.h>
#include <tinycrypt/constants.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdbool.h>
#include <unistd.h>

int hex2int (char hex)
{
    uint8_t dec;

    if ('0' <= hex && hex <= '9') dec = hex - '0';
    else if ('a' <= hex && hex <= 'f') dec = hex - 'a' + 10;
    else if ('A' <= hex && hex <= 'F') dec = hex - 'A' + 10;
    else return -1;

    return dec;
}

/*
    Convert hex string to byte string
    Return number of bytes written to buf, or 0 on error
*/
int hex2bin(uint8_t* buf, const size_t buflen, const char* hex,
            const size_t hexlen)
{
    int dec;

    if (buflen < hexlen / 2 + hexlen % 2)
    {
        return false;
    }

    /* if hexlen is uneven, insert leading zero nibble */
    if (hexlen % 2)
    {
        dec = hex2int(hex[0]);

        if (dec == -1)
            return false;

        buf[0] = dec;
        buf++;
        hex++;
    }

    /* regular hex conversion */
    for (size_t i = 0; i < hexlen / 2; i++)
    {
        dec = hex2int(hex[2 * i]);

        if (dec == -1)
        {
            return false;
        }

        buf[i] = dec << 4;
        dec = hex2int(hex[ 2 * i + 1]);

        if (dec == -1)
        {
            return false;
        }

        buf[i] += dec;
    }

    return hexlen / 2 + hexlen % 2;
}

/*
    Convert hex string to zero-padded nanoECC scalar
*/
void string2scalar(unsigned int* scalar, unsigned int num_word32, char* str)
{
    unsigned int num_bytes = 4 * num_word32;
    uint8_t tmp[num_bytes];
    size_t hexlen = strlen(str);
    int padding;

    if (0 > (padding = 2 * num_bytes - strlen(str)))
    {
        printf("Error: 2 * num_bytes(%d) < strlen(hex) (%zu)\n",
               2 * num_bytes, strlen(str));
        exit(-1);
    }

    memset(tmp, 0, padding / 2);

    if (false == hex2bin(tmp + padding / 2, num_bytes, str, hexlen))
    {
        exit(-1);
    }

    uECC_vli_bytesToNative(scalar, tmp, num_bytes);
}

void vli_print_bytes(uint8_t* vli, unsigned int size)
{
    for(unsigned i = 0; i < size; ++i)
    {
        printf("%02X ", (unsigned)vli[i]);
    }
}

void print_ecc_scalar(const char* label, const unsigned int* p_vli,
                      unsigned int num_word32)
{
    unsigned int i;

    if (label)
    {
        printf("%s = { ", label);
    }

    for(i = 0; i < num_word32 - 1; ++i)
    {
        printf("0x%08lX, ", (unsigned long)p_vli[i]);
    }

    printf("0x%08lX", (unsigned long)p_vli[i]);

    if (label)
    {
        printf(" };\n");
    }
}

int check_ecc_result(const int num, const char* name,
                     const unsigned int* expected,
                     const unsigned int* computed,
                     const unsigned int num_word32, const bool verbose)
{
    uint32_t num_bytes = 4 * num_word32;

    if (memcmp(computed, expected, num_bytes))
    {
        TC_PRINT("\n  Vector #%02d check %s - FAILURE:\n\n", num, name);
        print_ecc_scalar("Expected", expected, num_word32);
        print_ecc_scalar("Computed", computed, num_word32);
        TC_PRINT("\n");
        return TC_FAIL;
    }

    if (verbose)
    {
        TC_PRINT("  Vector #%02d check %s - success\n", num, name);
    }

    return TC_PASS;
}

int check_code(const int num, const char* name, const int expected,
               const int computed, const int verbose)
{
    if (expected != computed)
    {
        TC_ERROR("\n  Vector #%02d check %s - FAILURE:\n", num, name);
        TC_ERROR("\n  Expected: %d, computed: %d\n\n", expected, computed);
        return TC_FAIL;
    }

    if (verbose)
    {
        TC_PRINT("  Vector #%02d check %s - success (%d=%d)\n", num, name,
                 expected, computed);
    }

    return TC_PASS;
}

/* Test ecc_make_keys, and also as keygen part of other tests */
int keygen_vectors(char** d_vec, char** qx_vec, char** qy_vec, int tests,
                   bool verbose)
{
    unsigned int pub[2 * NUM_ECC_WORDS];
    unsigned int d[NUM_ECC_WORDS];
    unsigned int prv[NUM_ECC_WORDS];
    unsigned int result = TC_PASS;
    /* expected outputs (converted input vectors) */
    unsigned int exp_pub[2 * NUM_ECC_WORDS];
    unsigned int exp_prv[NUM_ECC_WORDS];

    for (int i = 0; i < tests; i++)
    {
        string2scalar(exp_prv, NUM_ECC_WORDS, d_vec[i]);
        string2scalar(exp_pub, NUM_ECC_WORDS, qx_vec[i]);
        string2scalar(exp_pub + NUM_ECC_WORDS, NUM_ECC_WORDS, qy_vec[i]);
        /*
            Feed prvkey vector as padded random seed into ecc_make_key.
            Internal mod-reduction will be zero-op and generate correct prv/pub
        */
        memset(d, 0, NUM_ECC_WORDS);
        string2scalar(d, NUM_ECC_WORDS, d_vec[i]);
        uint8_t pub_bytes[2*NUM_ECC_BYTES];
        uint8_t prv_bytes[NUM_ECC_BYTES];
        uECC_make_key_with_d(pub_bytes, prv_bytes, d, uECC_secp256r1());
        uECC_vli_bytesToNative(prv, prv_bytes, NUM_ECC_BYTES);
        uECC_vli_bytesToNative(pub, pub_bytes, NUM_ECC_BYTES);
        uECC_vli_bytesToNative(pub + NUM_ECC_WORDS, pub_bytes + NUM_ECC_BYTES, NUM_ECC_BYTES);
        /* validate correctness of vector conversion and make_key() */
        result = check_ecc_result(i, "prv  ", exp_prv, prv,  NUM_ECC_WORDS, verbose);

        if (result == TC_FAIL)
        {
            return result;
        }

        result = check_ecc_result(i, "pub.x", exp_pub, pub,  NUM_ECC_WORDS, verbose);

        if (result == TC_FAIL)
        {
            return result;
        }

        result = check_ecc_result(i, "pub.y", exp_pub + NUM_ECC_WORDS, pub + NUM_ECC_WORDS,  NUM_ECC_WORDS, verbose);

        if (result == TC_FAIL)
        {
            return result;
        }
    }

    return result;
}
