/*
 *
 * FIPS-180-2 compliant SHA-256 implementation
 * Copyright (C) 2010 Paul Bakker.
 * Originally written (2003-2006) by Christophe Devine.
 *
 * This code is free software; you can redistribute it and/or
 * modify it, as a part of the International Chemical Identifier (InChI)
 * software, under the terms of the MIT license
 * https://opensource.org/license/mit
 *
 * Note that this licensing is only valid in combination with the InChI
 * software package, for all other cases contact Paul Bakker.
 */

/*
 *  The SHA-256 standard was published by NIST in 2002.
 *
 *  http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
 */

#ifndef _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_DEPRECATE 1
#endif

#include <string.h>
#include <stdio.h>

#include "sha2.h"

#include "mode.h"

#include "bcf_s.h"

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n, b, i)                                                                                                                            \
    {                                                                                                                                                     \
        (n) = ((unsigned long)(b)[(i)] << 24) | ((unsigned long)(b)[(i) + 1] << 16) | ((unsigned long)(b)[(i) + 2] << 8) | ((unsigned long)(b)[(i) + 3]); \
    }
#endif
#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n, b, i)                     \
    {                                              \
        (b)[(i)] = (unsigned char)((n) >> 24);     \
        (b)[(i) + 1] = (unsigned char)((n) >> 16); \
        (b)[(i) + 2] = (unsigned char)((n) >> 8);  \
        (b)[(i) + 3] = (unsigned char)((n));       \
    }
#endif

/*
 * SHA-2 context setup
 */
void sha2_starts(sha2_context *ctx)
{
    ctx->total[0] = 0;
    ctx->total[1] = 0;

    ctx->state[0] = 0x6A09E667;
    ctx->state[1] = 0xBB67AE85;
    ctx->state[2] = 0x3C6EF372;
    ctx->state[3] = 0xA54FF53A;
    ctx->state[4] = 0x510E527F;
    ctx->state[5] = 0x9B05688C;
    ctx->state[6] = 0x1F83D9AB;
    ctx->state[7] = 0x5BE0CD19;
}

static void sha2_process(sha2_context *ctx, unsigned char data[64])
{
    unsigned long temp1, temp2, W[64];
    unsigned long A, B, C, D, E, F, G, H;

    GET_UINT32_BE(W[0], data, 0);
    GET_UINT32_BE(W[1], data, 4);
    GET_UINT32_BE(W[2], data, 8);
    GET_UINT32_BE(W[3], data, 12);
    GET_UINT32_BE(W[4], data, 16);
    GET_UINT32_BE(W[5], data, 20);
    GET_UINT32_BE(W[6], data, 24);
    GET_UINT32_BE(W[7], data, 28);
    GET_UINT32_BE(W[8], data, 32);
    GET_UINT32_BE(W[9], data, 36);
    GET_UINT32_BE(W[10], data, 40);
    GET_UINT32_BE(W[11], data, 44);
    GET_UINT32_BE(W[12], data, 48);
    GET_UINT32_BE(W[13], data, 52);
    GET_UINT32_BE(W[14], data, 56);
    GET_UINT32_BE(W[15], data, 60);

#define SHR(x, n) ((x & 0xFFFFFFFF) >> n)
#define ROTR(x, n) (SHR(x, n) | (x << (32 - n)))

#define S0(x) (ROTR(x, 7) ^ ROTR(x, 18) ^ SHR(x, 3))
#define S1(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHR(x, 10))

#define S2(x) (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S3(x) (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))

#define F0(x, y, z) ((x & y) | (z & (x | y)))
#define F1(x, y, z) (z ^ (x & (y ^ z)))

#define R(t)                             \
    (                                    \
        W[t] = S1(W[t - 2]) + W[t - 7] + \
               S0(W[t - 15]) + W[t - 16])

#define P(a, b, c, d, e, f, g, h, x, K)          \
    {                                            \
        temp1 = h + S3(e) + F1(e, f, g) + K + x; \
        temp2 = S2(a) + F0(a, b, c);             \
        d += temp1;                              \
        h = temp1 + temp2;                       \
    }

    A = ctx->state[0];
    B = ctx->state[1];
    C = ctx->state[2];
    D = ctx->state[3];
    E = ctx->state[4];
    F = ctx->state[5];
    G = ctx->state[6];
    H = ctx->state[7];

    P(A, B, C, D, E, F, G, H, W[0], 0x428A2F98);
    P(H, A, B, C, D, E, F, G, W[1], 0x71374491);
    P(G, H, A, B, C, D, E, F, W[2], 0xB5C0FBCF);
    P(F, G, H, A, B, C, D, E, W[3], 0xE9B5DBA5);
    P(E, F, G, H, A, B, C, D, W[4], 0x3956C25B);
    P(D, E, F, G, H, A, B, C, W[5], 0x59F111F1);
    P(C, D, E, F, G, H, A, B, W[6], 0x923F82A4);
    P(B, C, D, E, F, G, H, A, W[7], 0xAB1C5ED5);
    P(A, B, C, D, E, F, G, H, W[8], 0xD807AA98);
    P(H, A, B, C, D, E, F, G, W[9], 0x12835B01);
    P(G, H, A, B, C, D, E, F, W[10], 0x243185BE);
    P(F, G, H, A, B, C, D, E, W[11], 0x550C7DC3);
    P(E, F, G, H, A, B, C, D, W[12], 0x72BE5D74);
    P(D, E, F, G, H, A, B, C, W[13], 0x80DEB1FE);
    P(C, D, E, F, G, H, A, B, W[14], 0x9BDC06A7);
    P(B, C, D, E, F, G, H, A, W[15], 0xC19BF174);
    P(A, B, C, D, E, F, G, H, R(16), 0xE49B69C1);
    P(H, A, B, C, D, E, F, G, R(17), 0xEFBE4786);
    P(G, H, A, B, C, D, E, F, R(18), 0x0FC19DC6);
    P(F, G, H, A, B, C, D, E, R(19), 0x240CA1CC);
    P(E, F, G, H, A, B, C, D, R(20), 0x2DE92C6F);
    P(D, E, F, G, H, A, B, C, R(21), 0x4A7484AA);
    P(C, D, E, F, G, H, A, B, R(22), 0x5CB0A9DC);
    P(B, C, D, E, F, G, H, A, R(23), 0x76F988DA);
    P(A, B, C, D, E, F, G, H, R(24), 0x983E5152);
    P(H, A, B, C, D, E, F, G, R(25), 0xA831C66D);
    P(G, H, A, B, C, D, E, F, R(26), 0xB00327C8);
    P(F, G, H, A, B, C, D, E, R(27), 0xBF597FC7);
    P(E, F, G, H, A, B, C, D, R(28), 0xC6E00BF3);
    P(D, E, F, G, H, A, B, C, R(29), 0xD5A79147);
    P(C, D, E, F, G, H, A, B, R(30), 0x06CA6351);
    P(B, C, D, E, F, G, H, A, R(31), 0x14292967);
    P(A, B, C, D, E, F, G, H, R(32), 0x27B70A85);
    P(H, A, B, C, D, E, F, G, R(33), 0x2E1B2138);
    P(G, H, A, B, C, D, E, F, R(34), 0x4D2C6DFC);
    P(F, G, H, A, B, C, D, E, R(35), 0x53380D13);
    P(E, F, G, H, A, B, C, D, R(36), 0x650A7354);
    P(D, E, F, G, H, A, B, C, R(37), 0x766A0ABB);
    P(C, D, E, F, G, H, A, B, R(38), 0x81C2C92E);
    P(B, C, D, E, F, G, H, A, R(39), 0x92722C85);
    P(A, B, C, D, E, F, G, H, R(40), 0xA2BFE8A1);
    P(H, A, B, C, D, E, F, G, R(41), 0xA81A664B);
    P(G, H, A, B, C, D, E, F, R(42), 0xC24B8B70);
    P(F, G, H, A, B, C, D, E, R(43), 0xC76C51A3);
    P(E, F, G, H, A, B, C, D, R(44), 0xD192E819);
    P(D, E, F, G, H, A, B, C, R(45), 0xD6990624);
    P(C, D, E, F, G, H, A, B, R(46), 0xF40E3585);
    P(B, C, D, E, F, G, H, A, R(47), 0x106AA070);
    P(A, B, C, D, E, F, G, H, R(48), 0x19A4C116);
    P(H, A, B, C, D, E, F, G, R(49), 0x1E376C08);
    P(G, H, A, B, C, D, E, F, R(50), 0x2748774C);
    P(F, G, H, A, B, C, D, E, R(51), 0x34B0BCB5);
    P(E, F, G, H, A, B, C, D, R(52), 0x391C0CB3);
    P(D, E, F, G, H, A, B, C, R(53), 0x4ED8AA4A);
    P(C, D, E, F, G, H, A, B, R(54), 0x5B9CCA4F);
    P(B, C, D, E, F, G, H, A, R(55), 0x682E6FF3);
    P(A, B, C, D, E, F, G, H, R(56), 0x748F82EE);
    P(H, A, B, C, D, E, F, G, R(57), 0x78A5636F);
    P(G, H, A, B, C, D, E, F, R(58), 0x84C87814);
    P(F, G, H, A, B, C, D, E, R(59), 0x8CC70208);
    P(E, F, G, H, A, B, C, D, R(60), 0x90BEFFFA);
    P(D, E, F, G, H, A, B, C, R(61), 0xA4506CEB);
    P(C, D, E, F, G, H, A, B, R(62), 0xBEF9A3F7);
    P(B, C, D, E, F, G, H, A, R(63), 0xC67178F2);

    ctx->state[0] += A;
    ctx->state[1] += B;
    ctx->state[2] += C;
    ctx->state[3] += D;
    ctx->state[4] += E;
    ctx->state[5] += F;
    ctx->state[6] += G;
    ctx->state[7] += H;
}

/*
 * SHA-2 process buffer
 */
void sha2_update(sha2_context *ctx, unsigned char *input, int ilen)
{
    int fill;
    unsigned long left;

    if (ilen <= 0)
        return;

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if (ctx->total[0] < (unsigned long)ilen)
        ctx->total[1]++;

    if (left && ilen >= fill)
    {
        memcpy((void *)(ctx->buffer + left),
               (void *)input, fill);
        sha2_process(ctx, ctx->buffer);
        input += fill;
        ilen -= fill;
        left = 0;
    }

    while (ilen >= 64) 
    {
        sha2_process(ctx, input); /* djb-rwth: ignoring LLVM warning as ilen >= 64 just in test case */
        input += 64;
        ilen -= 64;
    }

    if (ilen > 0)
    {
        memcpy((void *)(ctx->buffer + left),
               (void *)input, ilen);
    }
}

static const unsigned char sha2_padding[64] =
    {
        0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

/*
 * SHA-2 final digest
 */
void sha2_finish(sha2_context *ctx, unsigned char output[32])
{
    unsigned long last, padn;
    unsigned long high, low;
    unsigned char msglen[8];

    high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
    low = (ctx->total[0] << 3);

    PUT_UINT32_BE(high, msglen, 0);
    PUT_UINT32_BE(low, msglen, 4);

    last = ctx->total[0] & 0x3F;
    padn = (last < 56) ? (56 - last) : (120 - last);

    sha2_update(ctx, (unsigned char *)sha2_padding, padn);
    sha2_update(ctx, msglen, 8);

    PUT_UINT32_BE(ctx->state[0], output, 0);
    PUT_UINT32_BE(ctx->state[1], output, 4);
    PUT_UINT32_BE(ctx->state[2], output, 8);
    PUT_UINT32_BE(ctx->state[3], output, 12);
    PUT_UINT32_BE(ctx->state[4], output, 16);
    PUT_UINT32_BE(ctx->state[5], output, 20);
    PUT_UINT32_BE(ctx->state[6], output, 24);
    PUT_UINT32_BE(ctx->state[7], output, 28);
}

/*
 * Output = SHA-2( file contents )
 */
int sha2_file(char *path, unsigned char output[32])
{
    FILE *f;
    size_t n;
    sha2_context ctx;
    unsigned char buf[1024];

    if ((f = fopen(path, "rb")) == NULL)
        return (1);

    sha2_starts(&ctx);

    while (!feof(f) && (n = fread(buf, 1, sizeof(buf), f)) > 0) /* djb-rwth: addressing LLVM warning */
        sha2_update(&ctx, buf, (int)n);

    sha2_finish(&ctx, output);

    fclose(f);
    return (0);
}

/*
 * Output = SHA-2( input buffer )
 */
void sha2_csum(unsigned char *input, int ilen,
               unsigned char output[32])
{
    sha2_context ctx;

    sha2_starts(&ctx);
    sha2_update(&ctx, input, ilen);
    sha2_finish(&ctx, output);
}

/*
 * Output = HMAC-SHA-2( input buffer, hmac key )
 */
void sha2_hmac(unsigned char *key, int keylen,
               unsigned char *input, int ilen,
               unsigned char output[32])
{
    int i;
    sha2_context ctx;
    unsigned char k_ipad[64];
    unsigned char k_opad[64];
    unsigned char tmpbuf[32];

    memset(k_ipad, 0x36, 64); /* djb-rwth: memset_s C11/Annex K variant? */
    memset(k_opad, 0x5C, 64); /* djb-rwth: memset_s C11/Annex K variant? */

    for (i = 0; i < keylen; i++)
    {
        if (i >= 64)
            break;

        k_ipad[i] ^= key[i];
        k_opad[i] ^= key[i];
    }

    sha2_starts(&ctx);
    sha2_update(&ctx, k_ipad, 64);
    sha2_update(&ctx, input, ilen);
    sha2_finish(&ctx, tmpbuf);

    sha2_starts(&ctx);
    sha2_update(&ctx, k_opad, 64);
    sha2_update(&ctx, tmpbuf, 32);
    sha2_finish(&ctx, output);

    memset(k_ipad, 0, 64);                 /* djb-rwth: memset_s C11/Annex K variant? */
    memset(k_opad, 0, 64);                 /* djb-rwth: memset_s C11/Annex K variant? */
    memset(tmpbuf, 0, 32);                 /* djb-rwth: memset_s C11/Annex K variant? */
    memset(&ctx, 0, sizeof(sha2_context)); /* djb-rwth: memset_s C11/Annex K variant? */
}

#ifdef SELF_TEST
/*
 * FIPS-180-2 test vectors
 */
static const char sha2_test_str[3][57] =
    {
        {"abc"},
        {"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"},
        {""}};

static const unsigned char sha2_test_sum[3][32] =
    {
        {0xBA, 0x78, 0x16, 0xBF, 0x8F, 0x01, 0xCF, 0xEA,
         0x41, 0x41, 0x40, 0xDE, 0x5D, 0xAE, 0x22, 0x23,
         0xB0, 0x03, 0x61, 0xA3, 0x96, 0x17, 0x7A, 0x9C,
         0xB4, 0x10, 0xFF, 0x61, 0xF2, 0x00, 0x15, 0xAD},
        {0x24, 0x8D, 0x6A, 0x61, 0xD2, 0x06, 0x38, 0xB8,
         0xE5, 0xC0, 0x26, 0x93, 0x0C, 0x3E, 0x60, 0x39,
         0xA3, 0x3C, 0xE4, 0x59, 0x64, 0xFF, 0x21, 0x67,
         0xF6, 0xEC, 0xED, 0xD4, 0x19, 0xDB, 0x06, 0xC1},
        {0xCD, 0xC7, 0x6E, 0x5C, 0x99, 0x14, 0xFB, 0x92,
         0x81, 0xA1, 0xC7, 0xE2, 0x84, 0xD7, 0x3E, 0x67,
         0xF1, 0x80, 0x9A, 0x48, 0xA4, 0x97, 0x20, 0x0E,
         0x04, 0x6D, 0x39, 0xCC, 0xC7, 0x11, 0x2C, 0xD0}};

/*
 * Checkup routine
 */
int sha2_self_test(void)
{
    int i, j;
    unsigned char buf[1000];
    unsigned char sha2sum[32];
    sha2_context ctx;

    for (i = 0; i < 3; i++)
    {
        printf("  SHA-256 test #%d: ", i + 1);

        sha2_starts(&ctx);

        if (i < 2)
            sha2_update(&ctx, (unsigned char *)sha2_test_str[i],
                        strlen(sha2_test_str[i]));
        else
        {
            memset(buf, 'a', 1000);
            for (j = 0; j < 1000; j++)
                sha2_update(&ctx, buf, 1000);
        }

        sha2_finish(&ctx, sha2sum);

        if (memcmp(sha2sum, sha2_test_sum[i], 20) != 0)
        {
            printf("failed\n");
            return (1);
        }

        printf("passed\n");
    }

    printf("\n");
    return (0);
}
#else
int sha2_self_test(void)
{
    return (0);
}

#endif
