
/*-
 * Copyright 2005,2007,2009 Colin Percival
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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 AUTHOR 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 AUTHOR 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.
 *
 */

#include "crypto_hash_sha256.h"
#include "utils.h"
#include "private/common.h"

#include <sys/types.h>

#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

static void
be32enc_vect(unsigned char *dst, const uint32_t *src, size_t len)
{
    size_t i;

    for (i = 0; i < len / 4; i++) {
        STORE32_BE(dst + i * 4, src[i]);
    }
}

static void
be32dec_vect(uint32_t *dst, const unsigned char *src, size_t len)
{
    size_t i;

    for (i = 0; i < len / 4; i++) {
        dst[i] = LOAD32_BE(src + i * 4);
    }
}

#define Ch(x, y, z)     ((x & (y ^ z)) ^ z)
#define Maj(x, y, z)    ((x & (y | z)) | (y & z))
#define SHR(x, n)       (x >> n)
#define ROTR(x, n)      ((x >> n) | (x << (32 - n)))
#define S0(x)           (ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define S1(x)           (ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#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 RND(a, b, c, d, e, f, g, h, k)              \
    t0 = h + S1(e) + Ch(e, f, g) + k;               \
    t1 = S0(a) + Maj(a, b, c);                      \
    d += t0;                                        \
    h  = t0 + t1;

#define RNDr(S, W, i, k)                    \
    RND(S[(64 - i) % 8], S[(65 - i) % 8],   \
        S[(66 - i) % 8], S[(67 - i) % 8],   \
        S[(68 - i) % 8], S[(69 - i) % 8],   \
        S[(70 - i) % 8], S[(71 - i) % 8],   \
        W[i] + k)

static void
SHA256_Transform(uint32_t *state, const unsigned char block[64])
{
    uint32_t W[64];
    uint32_t S[8];
    uint32_t t0, t1;
    int i;

    be32dec_vect(W, block, 64);
    for (i = 16; i < 64; i++) {
        W[i] = s1(W[i - 2]) + W[i - 7] + s0(W[i - 15]) + W[i - 16];
    }

    memcpy(S, state, 32);

    RNDr(S, W, 0, 0x428a2f98);
    RNDr(S, W, 1, 0x71374491);
    RNDr(S, W, 2, 0xb5c0fbcf);
    RNDr(S, W, 3, 0xe9b5dba5);
    RNDr(S, W, 4, 0x3956c25b);
    RNDr(S, W, 5, 0x59f111f1);
    RNDr(S, W, 6, 0x923f82a4);
    RNDr(S, W, 7, 0xab1c5ed5);
    RNDr(S, W, 8, 0xd807aa98);
    RNDr(S, W, 9, 0x12835b01);
    RNDr(S, W, 10, 0x243185be);
    RNDr(S, W, 11, 0x550c7dc3);
    RNDr(S, W, 12, 0x72be5d74);
    RNDr(S, W, 13, 0x80deb1fe);
    RNDr(S, W, 14, 0x9bdc06a7);
    RNDr(S, W, 15, 0xc19bf174);
    RNDr(S, W, 16, 0xe49b69c1);
    RNDr(S, W, 17, 0xefbe4786);
    RNDr(S, W, 18, 0x0fc19dc6);
    RNDr(S, W, 19, 0x240ca1cc);
    RNDr(S, W, 20, 0x2de92c6f);
    RNDr(S, W, 21, 0x4a7484aa);
    RNDr(S, W, 22, 0x5cb0a9dc);
    RNDr(S, W, 23, 0x76f988da);
    RNDr(S, W, 24, 0x983e5152);
    RNDr(S, W, 25, 0xa831c66d);
    RNDr(S, W, 26, 0xb00327c8);
    RNDr(S, W, 27, 0xbf597fc7);
    RNDr(S, W, 28, 0xc6e00bf3);
    RNDr(S, W, 29, 0xd5a79147);
    RNDr(S, W, 30, 0x06ca6351);
    RNDr(S, W, 31, 0x14292967);
    RNDr(S, W, 32, 0x27b70a85);
    RNDr(S, W, 33, 0x2e1b2138);
    RNDr(S, W, 34, 0x4d2c6dfc);
    RNDr(S, W, 35, 0x53380d13);
    RNDr(S, W, 36, 0x650a7354);
    RNDr(S, W, 37, 0x766a0abb);
    RNDr(S, W, 38, 0x81c2c92e);
    RNDr(S, W, 39, 0x92722c85);
    RNDr(S, W, 40, 0xa2bfe8a1);
    RNDr(S, W, 41, 0xa81a664b);
    RNDr(S, W, 42, 0xc24b8b70);
    RNDr(S, W, 43, 0xc76c51a3);
    RNDr(S, W, 44, 0xd192e819);
    RNDr(S, W, 45, 0xd6990624);
    RNDr(S, W, 46, 0xf40e3585);
    RNDr(S, W, 47, 0x106aa070);
    RNDr(S, W, 48, 0x19a4c116);
    RNDr(S, W, 49, 0x1e376c08);
    RNDr(S, W, 50, 0x2748774c);
    RNDr(S, W, 51, 0x34b0bcb5);
    RNDr(S, W, 52, 0x391c0cb3);
    RNDr(S, W, 53, 0x4ed8aa4a);
    RNDr(S, W, 54, 0x5b9cca4f);
    RNDr(S, W, 55, 0x682e6ff3);
    RNDr(S, W, 56, 0x748f82ee);
    RNDr(S, W, 57, 0x78a5636f);
    RNDr(S, W, 58, 0x84c87814);
    RNDr(S, W, 59, 0x8cc70208);
    RNDr(S, W, 60, 0x90befffa);
    RNDr(S, W, 61, 0xa4506ceb);
    RNDr(S, W, 62, 0xbef9a3f7);
    RNDr(S, W, 63, 0xc67178f2);

    for (i = 0; i < 8; i++) {
        state[i] += S[i];
    }

    sodium_memzero((void *) W, sizeof W);
    sodium_memzero((void *) S, sizeof S);
    sodium_memzero((void *) &t0, sizeof t0);
    sodium_memzero((void *) &t1, sizeof t1);
}

static unsigned char PAD[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
};

static void
SHA256_Pad(crypto_hash_sha256_state *state)
{
    unsigned char len[8];
    uint32_t r, plen;

    STORE64_BE(len, state->count);

    r = (state->count >> 3) & 0x3f;
    plen = (r < 56) ? (56 - r) : (120 - r);
    crypto_hash_sha256_update(state, PAD, (unsigned long long) plen);

    crypto_hash_sha256_update(state, len, 8);
}

int
crypto_hash_sha256_init(crypto_hash_sha256_state *state)
{
    static const uint32_t sha256_initstate[8] = {
        0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
        0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
    };

    state->count = (uint64_t) 0U;
    memcpy(state->state, sha256_initstate, sizeof sha256_initstate);

    return 0;
}

int
crypto_hash_sha256_update(crypto_hash_sha256_state *state,
                          const unsigned char *in,
                          unsigned long long inlen)
{
    unsigned long long i;
    uint32_t r;

    if (inlen <= 0U) {
        return 0;
    }
    r = (state->count >> 3) & 0x3f;
    state->count += (uint64_t)(inlen) << 3;

    if (inlen < 64 - r) {
        for (i = 0; i < inlen; i++) {
            state->buf[r + i] = in[i];
        }
        return 0;
    }
    for (i = 0; i < 64 - r; i++) {
        state->buf[r + i] = in[i];
    }
    SHA256_Transform(state->state, state->buf);
    in += 64 - r;
    inlen -= 64 - r;

    while (inlen >= 64) {
        SHA256_Transform(state->state, in);
        in += 64;
        inlen -= 64;
    }
    inlen &= 63;
    for (i = 0; i < inlen; i++) {
        state->buf[i] = in[i];
    }
    return 0;
}

int
crypto_hash_sha256_final(crypto_hash_sha256_state *state,
                         unsigned char *out)
{
    SHA256_Pad(state);
    be32enc_vect(out, state->state, 32);
    sodium_memzero((void *) state, sizeof *state);

    return 0;
}

int
crypto_hash_sha256(unsigned char *out, const unsigned char *in,
                   unsigned long long inlen)
{
    crypto_hash_sha256_state state;

    crypto_hash_sha256_init(&state);
    crypto_hash_sha256_update(&state, in, inlen);
    crypto_hash_sha256_final(&state, out);

    return 0;
}
