// Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <openssl/cast.h>
#include <openssl/cipher.h>
#include <openssl/obj.h>

#include <assert.h>

#include "../../crypto/fipsmodule/cipher/internal.h"
#include "../../crypto/internal.h"
#include "../macros.h"
#include "internal.h"


using namespace bssl;

void CAST_ecb_encrypt(const uint8_t in[CAST_BLOCK], uint8_t out[CAST_BLOCK],
                      const CAST_KEY *ks, int enc) {
  uint32_t d[2];

  n2l(in, d[0]);
  n2l(in, d[1]);
  if (enc) {
    CAST_encrypt(d, ks);
  } else {
    CAST_decrypt(d, ks);
  }
  l2n(d[0], out);
  l2n(d[1], out);
}

#define E_CAST(n, key, L, R, OP1, OP2, OP3)                          \
  {                                                                  \
    uint32_t a, b, c, d;                                             \
    t = (key[n * 2] OP1 R) & 0xffffffff;                             \
    t = CRYPTO_rotl_u32(t, (key[n * 2 + 1]));                        \
    a = CAST_S_table0[(t >> 8) & 0xff];                              \
    b = CAST_S_table1[(t) & 0xff];                                   \
    c = CAST_S_table2[(t >> 24) & 0xff];                             \
    d = CAST_S_table3[(t >> 16) & 0xff];                             \
    L ^= (((((a OP2 b) & 0xffffffffL) OP3 c) & 0xffffffffL) OP1 d) & \
         0xffffffffL;                                                \
  }

void CAST_encrypt(uint32_t data[2], const CAST_KEY *key) {
  uint32_t l, r, t;
  const uint32_t *k;

  k = &key->data[0];
  l = data[0];
  r = data[1];

  E_CAST(0, k, l, r, +, ^, -);
  E_CAST(1, k, r, l, ^, -, +);
  E_CAST(2, k, l, r, -, +, ^);
  E_CAST(3, k, r, l, +, ^, -);
  E_CAST(4, k, l, r, ^, -, +);
  E_CAST(5, k, r, l, -, +, ^);
  E_CAST(6, k, l, r, +, ^, -);
  E_CAST(7, k, r, l, ^, -, +);
  E_CAST(8, k, l, r, -, +, ^);
  E_CAST(9, k, r, l, +, ^, -);
  E_CAST(10, k, l, r, ^, -, +);
  E_CAST(11, k, r, l, -, +, ^);

  if (!key->short_key) {
    E_CAST(12, k, l, r, +, ^, -);
    E_CAST(13, k, r, l, ^, -, +);
    E_CAST(14, k, l, r, -, +, ^);
    E_CAST(15, k, r, l, +, ^, -);
  }

  data[1] = l & 0xffffffffL;
  data[0] = r & 0xffffffffL;
}

void CAST_decrypt(uint32_t data[2], const CAST_KEY *key) {
  uint32_t l, r, t;
  const uint32_t *k;

  k = &key->data[0];
  l = data[0];
  r = data[1];

  if (!key->short_key) {
    E_CAST(15, k, l, r, +, ^, -);
    E_CAST(14, k, r, l, -, +, ^);
    E_CAST(13, k, l, r, ^, -, +);
    E_CAST(12, k, r, l, +, ^, -);
  }

  E_CAST(11, k, l, r, -, +, ^);
  E_CAST(10, k, r, l, ^, -, +);
  E_CAST(9, k, l, r, +, ^, -);
  E_CAST(8, k, r, l, -, +, ^);
  E_CAST(7, k, l, r, ^, -, +);
  E_CAST(6, k, r, l, +, ^, -);
  E_CAST(5, k, l, r, -, +, ^);
  E_CAST(4, k, r, l, ^, -, +);
  E_CAST(3, k, l, r, +, ^, -);
  E_CAST(2, k, r, l, -, +, ^);
  E_CAST(1, k, l, r, ^, -, +);
  E_CAST(0, k, r, l, +, ^, -);

  data[1] = l & 0xffffffffL;
  data[0] = r & 0xffffffffL;
}

void CAST_cbc_encrypt(const uint8_t *in, uint8_t *out, size_t length,
                      const CAST_KEY *ks, uint8_t iv[8], int enc) {
  assert(length % CAST_BLOCK == 0);
  uint32_t tin0, tin1;
  uint32_t tout0, tout1, xor0, xor1;
  size_t l = length;
  uint32_t tin[2];

  if (enc) {
    n2l(iv, tout0);
    n2l(iv, tout1);
    iv -= 8;
    while (l >= 8) {
      n2l(in, tin0);
      n2l(in, tin1);
      tin0 ^= tout0;
      tin1 ^= tout1;
      tin[0] = tin0;
      tin[1] = tin1;
      CAST_encrypt(tin, ks);
      tout0 = tin[0];
      tout1 = tin[1];
      l2n(tout0, out);
      l2n(tout1, out);
      l -= 8;
    }
    if (l != 0) {
      n2ln(in, tin0, tin1, l);
      tin0 ^= tout0;
      tin1 ^= tout1;
      tin[0] = tin0;
      tin[1] = tin1;
      CAST_encrypt(tin, ks);
      tout0 = tin[0];
      tout1 = tin[1];
      l2n(tout0, out);
      l2n(tout1, out);
    }
    l2n(tout0, iv);
    l2n(tout1, iv);
  } else {
    n2l(iv, xor0);
    n2l(iv, xor1);
    iv -= 8;
    while (l >= 8) {
      n2l(in, tin0);
      n2l(in, tin1);
      tin[0] = tin0;
      tin[1] = tin1;
      CAST_decrypt(tin, ks);
      tout0 = tin[0] ^ xor0;
      tout1 = tin[1] ^ xor1;
      l2n(tout0, out);
      l2n(tout1, out);
      xor0 = tin0;
      xor1 = tin1;
      l -= 8;
    }
    if (l != 0) {
      n2l(in, tin0);
      n2l(in, tin1);
      tin[0] = tin0;
      tin[1] = tin1;
      CAST_decrypt(tin, ks);
      tout0 = tin[0] ^ xor0;
      tout1 = tin[1] ^ xor1;
      l2nn(tout0, tout1, out, l);
      xor0 = tin0;
      xor1 = tin1;
    }
    l2n(xor0, iv);
    l2n(xor1, iv);
  }
  tin0 = tin1 = tout0 = tout1 = xor0 = xor1 = 0;
  tin[0] = tin[1] = 0;
}

#define CAST_exp(l, A, a, n)   \
  A[n / 4] = l;                \
  a[n + 3] = (l) & 0xff;       \
  a[n + 2] = (l >> 8) & 0xff;  \
  a[n + 1] = (l >> 16) & 0xff; \
  a[n + 0] = (l >> 24) & 0xff;
#define S4 bssl::CAST_S_table4
#define S5 bssl::CAST_S_table5
#define S6 bssl::CAST_S_table6
#define S7 bssl::CAST_S_table7

void CAST_set_key(CAST_KEY *key, size_t len, const uint8_t *data) {
  uint32_t x[16];
  uint32_t z[16];
  uint32_t k[32];
  uint32_t X[4], Z[4];
  uint32_t l, *K;
  size_t i;

  for (i = 0; i < 16; i++) {
    x[i] = 0;
  }

  if (len > 16) {
    len = 16;
  }

  for (i = 0; i < len; i++) {
    x[i] = data[i];
  }

  if (len <= 10) {
    key->short_key = 1;
  } else {
    key->short_key = 0;
  }

  K = &k[0];
  X[0] = ((x[0] << 24) | (x[1] << 16) | (x[2] << 8) | x[3]) & 0xffffffffL;
  X[1] = ((x[4] << 24) | (x[5] << 16) | (x[6] << 8) | x[7]) & 0xffffffffL;
  X[2] = ((x[8] << 24) | (x[9] << 16) | (x[10] << 8) | x[11]) & 0xffffffffL;
  X[3] = ((x[12] << 24) | (x[13] << 16) | (x[14] << 8) | x[15]) & 0xffffffffL;

  for (;;) {
    l = X[0] ^ S4[x[13]] ^ S5[x[15]] ^ S6[x[12]] ^ S7[x[14]] ^ S6[x[8]];
    CAST_exp(l, Z, z, 0);
    l = X[2] ^ S4[z[0]] ^ S5[z[2]] ^ S6[z[1]] ^ S7[z[3]] ^ S7[x[10]];
    CAST_exp(l, Z, z, 4);
    l = X[3] ^ S4[z[7]] ^ S5[z[6]] ^ S6[z[5]] ^ S7[z[4]] ^ S4[x[9]];
    CAST_exp(l, Z, z, 8);
    l = X[1] ^ S4[z[10]] ^ S5[z[9]] ^ S6[z[11]] ^ S7[z[8]] ^ S5[x[11]];
    CAST_exp(l, Z, z, 12);

    K[0] = S4[z[8]] ^ S5[z[9]] ^ S6[z[7]] ^ S7[z[6]] ^ S4[z[2]];
    K[1] = S4[z[10]] ^ S5[z[11]] ^ S6[z[5]] ^ S7[z[4]] ^ S5[z[6]];
    K[2] = S4[z[12]] ^ S5[z[13]] ^ S6[z[3]] ^ S7[z[2]] ^ S6[z[9]];
    K[3] = S4[z[14]] ^ S5[z[15]] ^ S6[z[1]] ^ S7[z[0]] ^ S7[z[12]];

    l = Z[2] ^ S4[z[5]] ^ S5[z[7]] ^ S6[z[4]] ^ S7[z[6]] ^ S6[z[0]];
    CAST_exp(l, X, x, 0);
    l = Z[0] ^ S4[x[0]] ^ S5[x[2]] ^ S6[x[1]] ^ S7[x[3]] ^ S7[z[2]];
    CAST_exp(l, X, x, 4);
    l = Z[1] ^ S4[x[7]] ^ S5[x[6]] ^ S6[x[5]] ^ S7[x[4]] ^ S4[z[1]];
    CAST_exp(l, X, x, 8);
    l = Z[3] ^ S4[x[10]] ^ S5[x[9]] ^ S6[x[11]] ^ S7[x[8]] ^ S5[z[3]];
    CAST_exp(l, X, x, 12);

    K[4] = S4[x[3]] ^ S5[x[2]] ^ S6[x[12]] ^ S7[x[13]] ^ S4[x[8]];
    K[5] = S4[x[1]] ^ S5[x[0]] ^ S6[x[14]] ^ S7[x[15]] ^ S5[x[13]];
    K[6] = S4[x[7]] ^ S5[x[6]] ^ S6[x[8]] ^ S7[x[9]] ^ S6[x[3]];
    K[7] = S4[x[5]] ^ S5[x[4]] ^ S6[x[10]] ^ S7[x[11]] ^ S7[x[7]];

    l = X[0] ^ S4[x[13]] ^ S5[x[15]] ^ S6[x[12]] ^ S7[x[14]] ^ S6[x[8]];
    CAST_exp(l, Z, z, 0);
    l = X[2] ^ S4[z[0]] ^ S5[z[2]] ^ S6[z[1]] ^ S7[z[3]] ^ S7[x[10]];
    CAST_exp(l, Z, z, 4);
    l = X[3] ^ S4[z[7]] ^ S5[z[6]] ^ S6[z[5]] ^ S7[z[4]] ^ S4[x[9]];
    CAST_exp(l, Z, z, 8);
    l = X[1] ^ S4[z[10]] ^ S5[z[9]] ^ S6[z[11]] ^ S7[z[8]] ^ S5[x[11]];
    CAST_exp(l, Z, z, 12);

    K[8] = S4[z[3]] ^ S5[z[2]] ^ S6[z[12]] ^ S7[z[13]] ^ S4[z[9]];
    K[9] = S4[z[1]] ^ S5[z[0]] ^ S6[z[14]] ^ S7[z[15]] ^ S5[z[12]];
    K[10] = S4[z[7]] ^ S5[z[6]] ^ S6[z[8]] ^ S7[z[9]] ^ S6[z[2]];
    K[11] = S4[z[5]] ^ S5[z[4]] ^ S6[z[10]] ^ S7[z[11]] ^ S7[z[6]];

    l = Z[2] ^ S4[z[5]] ^ S5[z[7]] ^ S6[z[4]] ^ S7[z[6]] ^ S6[z[0]];
    CAST_exp(l, X, x, 0);
    l = Z[0] ^ S4[x[0]] ^ S5[x[2]] ^ S6[x[1]] ^ S7[x[3]] ^ S7[z[2]];
    CAST_exp(l, X, x, 4);
    l = Z[1] ^ S4[x[7]] ^ S5[x[6]] ^ S6[x[5]] ^ S7[x[4]] ^ S4[z[1]];
    CAST_exp(l, X, x, 8);
    l = Z[3] ^ S4[x[10]] ^ S5[x[9]] ^ S6[x[11]] ^ S7[x[8]] ^ S5[z[3]];
    CAST_exp(l, X, x, 12);

    K[12] = S4[x[8]] ^ S5[x[9]] ^ S6[x[7]] ^ S7[x[6]] ^ S4[x[3]];
    K[13] = S4[x[10]] ^ S5[x[11]] ^ S6[x[5]] ^ S7[x[4]] ^ S5[x[7]];
    K[14] = S4[x[12]] ^ S5[x[13]] ^ S6[x[3]] ^ S7[x[2]] ^ S6[x[8]];
    K[15] = S4[x[14]] ^ S5[x[15]] ^ S6[x[1]] ^ S7[x[0]] ^ S7[x[13]];
    if (K != k) {
      break;
    }
    K += 16;
  }

  for (i = 0; i < 16; i++) {
    key->data[i * 2] = k[i];
    key->data[i * 2 + 1] = ((k[i + 16]) + 16) & 0x1f;
  }
}

// The input and output encrypted as though 64bit cfb mode is being used. The
// extra state information to record how much of the 64bit block we have used
// is contained in *num.
void CAST_cfb64_encrypt(const uint8_t *in, uint8_t *out, size_t length,
                        const CAST_KEY *schedule, uint8_t ivec[8], int *num,
                        int enc) {
  uint32_t v0, v1, t;
  int n = *num;
  size_t l = length;
  uint32_t ti[2];
  uint8_t *iv, c, cc;

  iv = ivec;
  if (enc) {
    while (l--) {
      if (n == 0) {
        n2l(iv, v0);
        ti[0] = v0;
        n2l(iv, v1);
        ti[1] = v1;
        CAST_encrypt((uint32_t *)ti, schedule);
        iv = ivec;
        t = ti[0];
        l2n(t, iv);
        t = ti[1];
        l2n(t, iv);
        iv = ivec;
      }
      c = *(in++) ^ iv[n];
      *(out++) = c;
      iv[n] = c;
      n = (n + 1) & 0x07;
    }
  } else {
    while (l--) {
      if (n == 0) {
        n2l(iv, v0);
        ti[0] = v0;
        n2l(iv, v1);
        ti[1] = v1;
        CAST_encrypt((uint32_t *)ti, schedule);
        iv = ivec;
        t = ti[0];
        l2n(t, iv);
        t = ti[1];
        l2n(t, iv);
        iv = ivec;
      }
      cc = *(in++);
      c = iv[n];
      iv[n] = cc;
      *(out++) = c ^ cc;
      n = (n + 1) & 0x07;
    }
  }
  v0 = v1 = ti[0] = ti[1] = t = c = cc = 0;
  *num = n;
}

static int cast_init_key(EVP_CIPHER_CTX *ctx, const uint8_t *key,
                         const uint8_t *iv, int enc) {
  CAST_KEY *cast_key = reinterpret_cast<CAST_KEY *>(ctx->cipher_data);
  CAST_set_key(cast_key, ctx->key_len, key);
  return 1;
}

static int cast_ecb_cipher_update(EVP_CIPHER_CTX *ctx, uint8_t *out,
                                  const uint8_t *in, size_t len) {
  CAST_KEY *cast_key = reinterpret_cast<CAST_KEY *>(ctx->cipher_data);

  while (len >= CAST_BLOCK) {
    CAST_ecb_encrypt(in, out, cast_key, ctx->encrypt);
    in += CAST_BLOCK;
    out += CAST_BLOCK;
    len -= CAST_BLOCK;
  }
  assert(len == 0);

  return 1;
}

static int cast_cbc_cipher_update(EVP_CIPHER_CTX *ctx, uint8_t *out,
                                  const uint8_t *in, size_t len) {
  CAST_KEY *cast_key = reinterpret_cast<CAST_KEY *>(ctx->cipher_data);
  CAST_cbc_encrypt(in, out, len, cast_key, ctx->iv, ctx->encrypt);
  return 1;
}

static const EVP_CIPHER cast5_ecb = {
    /* nid= */ NID_cast5_ecb,
    /* block_size= */ CAST_BLOCK,
    /* key_len= */ CAST_KEY_LENGTH,
    /* iv_len= */ CAST_BLOCK,
    /* ctx_size= */ sizeof(CAST_KEY),
    /* flags= */ EVP_CIPH_ECB_MODE | EVP_CIPH_VARIABLE_LENGTH,
    /* init= */ cast_init_key,
    /* cipher_update= */ cast_ecb_cipher_update,
    /* cipher_final= */ nullptr,
    /* update_aad= */ nullptr,
    /* cleanup= */ nullptr,
    /* ctrl= */ nullptr,
};

static const EVP_CIPHER cast5_cbc = {
    /* nid= */ NID_cast5_cbc,
    /* block_size= */ CAST_BLOCK,
    /* key_len= */ CAST_KEY_LENGTH,
    /* iv_len= */ CAST_BLOCK,
    /* ctx_size= */ sizeof(CAST_KEY),
    /* flags= */ EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH,
    /* init= */ cast_init_key,
    /* cipher_update= */ cast_cbc_cipher_update,
    /* cipher_final= */ nullptr,
    /* update_aad= */ nullptr,
    /* cleanup= */ nullptr,
    /* ctrl= */ nullptr,
};

const EVP_CIPHER *EVP_cast5_ecb() { return &cast5_ecb; }

const EVP_CIPHER *EVP_cast5_cbc() { return &cast5_cbc; }