/*

 * Copyright (C) 2011-2018 Free Software Foundation, Inc.

 * Copyright (C) 2018 Red Hat, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GnuTLS.

 *

 * The GnuTLS is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>

 *

 */

/*

 * The following code is an implementation of the AES-128-CBC cipher

 * using VIA Padlock instruction set. 

 */

#include "errors.h"

#include "gnutls_int.h"

#include <gnutls/crypto.h>

#include "errors.h"

#include <aes-x86.h>

#include <x86-common.h>

#include <nettle/aes.h>   /* for key generation in 192 and 256 bits */

#include <sha-padlock.h>

#include <aes-padlock.h>

static int

aes_cipher_init(gnutls_cipher_algorithm_t algorithm, void **_ctx, int enc)

{

  /* we use key size to distinguish */

  if (algorithm != GNUTLS_CIPHER_AES_128_CBC

      && algorithm != GNUTLS_CIPHER_AES_256_CBC

      && algorithm != GNUTLS_CIPHER_AES_192_CBC)

    return GNUTLS_E_INVALID_REQUEST;

  *_ctx = gnutls_calloc(1, sizeof(struct padlock_ctx));

  if (*_ctx == NULL) {

    gnutls_assert();

    return GNUTLS_E_MEMORY_ERROR;

  }

  ((struct padlock_ctx *)(*_ctx))->enc = enc;

  return 0;

}

int padlock_aes_cipher_setkey(void *_ctx, const void *userkey, size_t keysize)

{

  struct padlock_ctx *ctx = _ctx;

  struct padlock_cipher_data *pce;

  struct aes192_ctx nc192;

  struct aes256_ctx nc256;

  memset(_ctx, 0, sizeof(struct padlock_cipher_data));

  pce = ALIGN16(&ctx->expanded_key);

  pce->cword.b.encdec = (ctx->enc == 0);

  switch (keysize) {

  case 16:

    pce->cword.b.ksize = 0;

    pce->cword.b.rounds = 10;

    memcpy(pce->ks.rd_key, userkey, 16);

    pce->cword.b.keygen = 0;

    break;

  case 24:

    pce->cword.b.ksize = 1;

    pce->cword.b.rounds = 12;

    if (ctx->enc)

      aes192_set_encrypt_key(&nc192, userkey);

    else

      aes192_set_decrypt_key(&nc192, userkey);

    memcpy(pce->ks.rd_key, nc192.keys, sizeof(nc192.keys));

    pce->ks.rounds = _AES192_ROUNDS;

    pce->cword.b.keygen = 1;

    break;

  case 32:

    pce->cword.b.ksize = 2;

    pce->cword.b.rounds = 14;

    /* expand key using nettle */

    if (ctx->enc)

      aes256_set_encrypt_key(&nc256, userkey);

    else

      aes256_set_decrypt_key(&nc256, userkey);

    memcpy(pce->ks.rd_key, nc256.keys, sizeof(nc256.keys));

    pce->ks.rounds = _AES256_ROUNDS;

    pce->cword.b.keygen = 1;

    break;

  default:

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  }

  padlock_reload_key();

  return 0;

}

static int aes_setiv(void *_ctx, const void *iv, size_t iv_size)

{

  struct padlock_ctx *ctx = _ctx;

  struct padlock_cipher_data *pce;

  pce = ALIGN16(&ctx->expanded_key);

  if (iv_size != 16)

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  memcpy(pce->iv, iv, 16);

  return 0;

}

static int

padlock_aes_cbc_encrypt(void *_ctx, const void *src, size_t src_size,

      void *dst, size_t dst_size)

{

  struct padlock_ctx *ctx = _ctx;

  struct padlock_cipher_data *pce;

  int ret = 1;

  if (unlikely(dst_size < src_size))

    return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

  pce = ALIGN16(&ctx->expanded_key);

  if (src_size > 0)

    ret = padlock_cbc_encrypt(dst, src, pce, src_size);

  return ret ? 0 : GNUTLS_E_ENCRYPTION_FAILED;

}

static int

padlock_aes_cbc_decrypt(void *_ctx, const void *src, size_t src_size,

      void *dst, size_t dst_size)

{

  struct padlock_ctx *ctx = _ctx;

  struct padlock_cipher_data *pcd;

  int ret = 1;

  if (unlikely(dst_size < src_size))

    return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

  pcd = ALIGN16(&ctx->expanded_key);

  if (src_size > 0)

    padlock_cbc_encrypt(dst, src, pcd, src_size);

  return ret ? 0 : GNUTLS_E_ENCRYPTION_FAILED;

}

static void aes_deinit(void *_ctx)

{

  struct padlock_ctx *ctx = _ctx;

  zeroize_temp_key(ctx, sizeof(*ctx));

  gnutls_free(ctx);

}

const gnutls_crypto_cipher_st _gnutls_aes_padlock = {

  .init = aes_cipher_init,

  .setkey = padlock_aes_cipher_setkey,

  .setiv = aes_setiv,

  .encrypt = padlock_aes_cbc_encrypt,

  .decrypt = padlock_aes_cbc_decrypt,

  .deinit = aes_deinit,

};