/**
 * Copyright (c) 2013-2014 Tomas Dzetkulic
 * Copyright (c) 2013-2014 Pavol Rusnak
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
 * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include "pbkdf2.h"
#include <string.h>
#include "hmac.h"
#include "memzero.h"
#include "sha2.h"

void pbkdf2_hmac_sha256_Init(PBKDF2_HMAC_SHA256_CTX *pctx, const uint8_t *pass,
                             int passlen, const uint8_t *salt, int saltlen,
                             uint32_t blocknr) {
  SHA256_CTX ctx;
#if BYTE_ORDER == LITTLE_ENDIAN
  REVERSE32(blocknr, blocknr);
#endif

  hmac_sha256_prepare(pass, passlen, pctx->odig, pctx->idig);
  memzero(pctx->g, sizeof(pctx->g));
  pctx->g[8] = 0x80000000;
  pctx->g[15] = (SHA256_BLOCK_LENGTH + SHA256_DIGEST_LENGTH) * 8;

  memcpy(ctx.state, pctx->idig, sizeof(pctx->idig));
  ctx.bitcount = SHA256_BLOCK_LENGTH * 8;
  sha256_Update(&ctx, salt, saltlen);
  sha256_Update(&ctx, (uint8_t *)&blocknr, sizeof(blocknr));
  sha256_Final(&ctx, (uint8_t *)pctx->g);
#if BYTE_ORDER == LITTLE_ENDIAN
  for (uint32_t k = 0; k < SHA256_DIGEST_LENGTH / sizeof(uint32_t); k++) {
    REVERSE32(pctx->g[k], pctx->g[k]);
  }
#endif
  sha256_Transform(pctx->odig, pctx->g, pctx->g);
  memcpy(pctx->f, pctx->g, SHA256_DIGEST_LENGTH);
  pctx->first = 1;
}

void pbkdf2_hmac_sha256_Update(PBKDF2_HMAC_SHA256_CTX *pctx,
                               uint32_t iterations) {
  for (uint32_t i = pctx->first; i < iterations; i++) {
    sha256_Transform(pctx->idig, pctx->g, pctx->g);
    sha256_Transform(pctx->odig, pctx->g, pctx->g);
    for (uint32_t j = 0; j < SHA256_DIGEST_LENGTH / sizeof(uint32_t); j++) {
      pctx->f[j] ^= pctx->g[j];
    }
  }
  pctx->first = 0;
}

void pbkdf2_hmac_sha256_Final(PBKDF2_HMAC_SHA256_CTX *pctx, uint8_t *key) {
#if BYTE_ORDER == LITTLE_ENDIAN
  for (uint32_t k = 0; k < SHA256_DIGEST_LENGTH / sizeof(uint32_t); k++) {
    REVERSE32(pctx->f[k], pctx->f[k]);
  }
#endif
  memcpy(key, pctx->f, SHA256_DIGEST_LENGTH);
  memzero(pctx, sizeof(PBKDF2_HMAC_SHA256_CTX));
}

void pbkdf2_hmac_sha256(const uint8_t *pass, int passlen, const uint8_t *salt,
                        int saltlen, uint32_t iterations, uint8_t *key,
                        int keylen) {
  uint32_t last_block_size = keylen % SHA256_DIGEST_LENGTH;
  uint32_t blocks_count = keylen / SHA256_DIGEST_LENGTH;
  if (last_block_size) {
    blocks_count++;
  } else {
    last_block_size = SHA256_DIGEST_LENGTH;
  }
  for (uint32_t blocknr = 1; blocknr <= blocks_count; blocknr++) {
    PBKDF2_HMAC_SHA256_CTX pctx;
    pbkdf2_hmac_sha256_Init(&pctx, pass, passlen, salt, saltlen, blocknr);
    pbkdf2_hmac_sha256_Update(&pctx, iterations);
    uint8_t digest[SHA256_DIGEST_LENGTH];
    pbkdf2_hmac_sha256_Final(&pctx, digest);
    uint32_t key_offset = (blocknr - 1) * SHA256_DIGEST_LENGTH;
    if (blocknr < blocks_count) {
      memcpy(key + key_offset, digest, SHA256_DIGEST_LENGTH);
    } else {
      memcpy(key + key_offset, digest, last_block_size);
    }
  }
}

void pbkdf2_hmac_sha512_Init(PBKDF2_HMAC_SHA512_CTX *pctx, const uint8_t *pass,
                             int passlen, const uint8_t *salt, int saltlen,
                             uint32_t blocknr) {
  SHA512_CTX ctx;
#if BYTE_ORDER == LITTLE_ENDIAN
  REVERSE32(blocknr, blocknr);
#endif

  hmac_sha512_prepare(pass, passlen, pctx->odig, pctx->idig);
  memzero(pctx->g, sizeof(pctx->g));
  pctx->g[8] = 0x8000000000000000;
  pctx->g[15] = (SHA512_BLOCK_LENGTH + SHA512_DIGEST_LENGTH) * 8;

  memcpy(ctx.state, pctx->idig, sizeof(pctx->idig));
  ctx.bitcount[0] = SHA512_BLOCK_LENGTH * 8;
  ctx.bitcount[1] = 0;
  sha512_Update(&ctx, salt, saltlen);
  sha512_Update(&ctx, (uint8_t *)&blocknr, sizeof(blocknr));
  sha512_Final(&ctx, (uint8_t *)pctx->g);
#if BYTE_ORDER == LITTLE_ENDIAN
  for (uint32_t k = 0; k < SHA512_DIGEST_LENGTH / sizeof(uint64_t); k++) {
    REVERSE64(pctx->g[k], pctx->g[k]);
  }
#endif
  sha512_Transform(pctx->odig, pctx->g, pctx->g);
  memcpy(pctx->f, pctx->g, SHA512_DIGEST_LENGTH);
  pctx->first = 1;
}

void pbkdf2_hmac_sha512_Update(PBKDF2_HMAC_SHA512_CTX *pctx,
                               uint32_t iterations) {
  for (uint32_t i = pctx->first; i < iterations; i++) {
    sha512_Transform(pctx->idig, pctx->g, pctx->g);
    sha512_Transform(pctx->odig, pctx->g, pctx->g);
    for (uint32_t j = 0; j < SHA512_DIGEST_LENGTH / sizeof(uint64_t); j++) {
      pctx->f[j] ^= pctx->g[j];
    }
  }
  pctx->first = 0;
}

void pbkdf2_hmac_sha512_Final(PBKDF2_HMAC_SHA512_CTX *pctx, uint8_t *key) {
#if BYTE_ORDER == LITTLE_ENDIAN
  for (uint32_t k = 0; k < SHA512_DIGEST_LENGTH / sizeof(uint64_t); k++) {
    REVERSE64(pctx->f[k], pctx->f[k]);
  }
#endif
  memcpy(key, pctx->f, SHA512_DIGEST_LENGTH);
  memzero(pctx, sizeof(PBKDF2_HMAC_SHA512_CTX));
}

void pbkdf2_hmac_sha512(const uint8_t *pass, int passlen, const uint8_t *salt,
                        int saltlen, uint32_t iterations, uint8_t *key,
                        int keylen) {
  uint32_t last_block_size = keylen % SHA512_DIGEST_LENGTH;
  uint32_t blocks_count = keylen / SHA512_DIGEST_LENGTH;
  if (last_block_size) {
    blocks_count++;
  } else {
    last_block_size = SHA512_DIGEST_LENGTH;
  }
  for (uint32_t blocknr = 1; blocknr <= blocks_count; blocknr++) {
    PBKDF2_HMAC_SHA512_CTX pctx;
    pbkdf2_hmac_sha512_Init(&pctx, pass, passlen, salt, saltlen, blocknr);
    pbkdf2_hmac_sha512_Update(&pctx, iterations);
    uint8_t digest[SHA512_DIGEST_LENGTH];
    pbkdf2_hmac_sha512_Final(&pctx, digest);
    uint32_t key_offset = (blocknr - 1) * SHA512_DIGEST_LENGTH;
    if (blocknr < blocks_count) {
      memcpy(key + key_offset, digest, SHA512_DIGEST_LENGTH);
    } else {
      memcpy(key + key_offset, digest, last_block_size);
    }
  }
}