/*

 * Copyright (C) 2011-2012 Free Software Foundation, Inc.

 * Copyright (C) 2020 Red Hat, Inc.

 *

 * Authors: Nikos Mavrogiannopoulos, Anderson Toshiyuki Sasaki

 *

 * 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 wraps the CRYPTOGAMS implementation of the AES-XTS cipher

 * using Intel's AES instruction set.

 */

#include "errors.h"

#include "gnutls_int.h"

#include "fips.h"

#include <gnutls/crypto.h>

#include "aes-x86.h"

#include "x86-common.h"

struct x86_aes_xts_ctx {

  AES_KEY block_key;

  AES_KEY tweak_key;

  uint8_t iv[16];

  int enc;

};

static int x86_aes_xts_cipher_init(gnutls_cipher_algorithm_t algorithm,

           void **_ctx, int enc)

{

  if (algorithm != GNUTLS_CIPHER_AES_128_XTS &&

      algorithm != GNUTLS_CIPHER_AES_256_XTS)

    return GNUTLS_E_INVALID_REQUEST;

  *_ctx = gnutls_calloc(1, sizeof(struct x86_aes_xts_ctx));

  if (*_ctx == NULL) {

    gnutls_assert();

    return GNUTLS_E_MEMORY_ERROR;

  }

  ((struct x86_aes_xts_ctx *)(*_ctx))->enc = enc;

  return 0;

}

static int x86_aes_xts_cipher_setkey(void *_ctx, const void *userkey,

             size_t keysize)

{

  struct x86_aes_xts_ctx *ctx = _ctx;

  int ret;

  size_t keybits;

  const uint8_t *key = userkey;

  if ((keysize != 32) && (keysize != 64))

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  /* Check key block according to FIPS-140-2 IG A.9 */

  if (_gnutls_fips_mode_enabled()) {

    if (gnutls_memcmp(key, key + (keysize / 2), keysize / 2) == 0) {

      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

    }

  }

  /* Size in bits of each half for block and tweak (=keysize * 8 / 2) */

  keybits = keysize * 4;

  if (ctx->enc)

    ret = aesni_set_encrypt_key(key, keybits,

              ALIGN16(&ctx->block_key));

  else

    ret = aesni_set_decrypt_key(key, keybits,

              ALIGN16(&ctx->block_key));

  if (ret != 0)

    return gnutls_assert_val(GNUTLS_E_ENCRYPTION_FAILED);

  ret = aesni_set_encrypt_key(key + (keysize / 2), keybits,

            ALIGN16(&ctx->tweak_key));

  if (ret != 0)

    return gnutls_assert_val(GNUTLS_E_ENCRYPTION_FAILED);

  return 0;

}

static int x86_aes_xts_setiv(void *_ctx, const void *iv, size_t iv_size)

{

  struct x86_aes_xts_ctx *ctx = _ctx;

  if (iv_size != 16)

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

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

  return 0;

}

static int x86_aes_xts_encrypt(void *_ctx, const void *src, size_t src_size,

             void *dst, size_t dst_size)

{

  struct x86_aes_xts_ctx *ctx = _ctx;

  if (unlikely(dst_size < src_size))

    return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

  if (src_size < 16)

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  aesni_xts_encrypt(src, dst, src_size, ALIGN16(&ctx->block_key),

        ALIGN16(&ctx->tweak_key), ctx->iv);

  return 0;

}

static int x86_aes_xts_decrypt(void *_ctx, const void *src, size_t src_size,

             void *dst, size_t dst_size)

{

  struct x86_aes_xts_ctx *ctx = _ctx;

  if (unlikely(dst_size < src_size))

    return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

  if (src_size < 16)

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  aesni_xts_decrypt(src, dst, src_size, ALIGN16(&ctx->block_key),

        ALIGN16(&ctx->tweak_key), ctx->iv);

  return 0;

}

static void x86_aes_xts_deinit(void *_ctx)

{

  struct x86_aes_xts_ctx *ctx = _ctx;

  zeroize_temp_key(ctx, sizeof(*ctx));

  gnutls_free(ctx);

}

const gnutls_crypto_cipher_st _gnutls_aes_xts_x86_aesni = {

  .init = x86_aes_xts_cipher_init,

  .setkey = x86_aes_xts_cipher_setkey,

  .setiv = x86_aes_xts_setiv,

  .encrypt = x86_aes_xts_encrypt,

  .decrypt = x86_aes_xts_decrypt,

  .deinit = x86_aes_xts_deinit,

};