/*

 * Copyright (C) 2011-2012 Free Software Foundation, 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-GCM cipher

 */

#include "errors.h"

#include "gnutls_int.h"

#ifdef HAVE_LIBNETTLE

#include <gnutls/crypto.h>

#include "errors.h"

#include <aes-x86.h>

#include <x86-common.h>

#include <byteswap.h>

#include <nettle/gcm.h>

#include <aes-padlock.h>

#define GCM_BLOCK_SIZE 16

/* GCM mode 

 * Actually padlock doesn't include GCM mode. We just use

 * the ECB part of padlock and nettle for everything else.

 */

struct gcm_padlock_aes_ctx GCM_CTX(struct padlock_ctx);

static void padlock_aes_encrypt(const void *_ctx,

				size_t length, uint8_t * dst,

				const uint8_t * src)

{

	struct padlock_ctx *ctx = (void*)_ctx;

	struct padlock_cipher_data *pce;

	pce = ALIGN16(&ctx->expanded_key);

	if (length > 0)

		padlock_ecb_encrypt(dst, src, pce, length);

}

static void padlock_aes128_set_encrypt_key(struct padlock_ctx *_ctx,

					const uint8_t * key)

{

	struct padlock_ctx *ctx = _ctx;

	ctx->enc = 1;

	padlock_aes_cipher_setkey(_ctx, key, 16);

}

static void padlock_aes256_set_encrypt_key(struct padlock_ctx *_ctx,

					const uint8_t * key)

{

	struct padlock_ctx *ctx = _ctx;

	ctx->enc = 1;

	padlock_aes_cipher_setkey(_ctx, key, 32);

}

static void aes_gcm_deinit(void *_ctx)

{

	struct padlock_ctx *ctx = _ctx;

	zeroize_temp_key(ctx, sizeof(*ctx));

	gnutls_free(ctx);

}

static int

aes_gcm_cipher_init(gnutls_cipher_algorithm_t algorithm, void **_ctx,

		    int enc)

{

	/* we use key size to distinguish */

	if (algorithm != GNUTLS_CIPHER_AES_128_GCM &&

	    algorithm != GNUTLS_CIPHER_AES_256_GCM)

		return GNUTLS_E_INVALID_REQUEST;

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

	if (*_ctx == NULL) {

		gnutls_assert();

		return GNUTLS_E_MEMORY_ERROR;

	}

	return 0;

}

static int

aes_gcm_cipher_setkey(void *_ctx, const void *key, size_t keysize)

{

	struct gcm_padlock_aes_ctx *ctx = _ctx;

	if (keysize == 16) {

		GCM_SET_KEY(ctx, padlock_aes128_set_encrypt_key, padlock_aes_encrypt,

			    key);

	} else if (keysize == 32) {

		GCM_SET_KEY(ctx, padlock_aes256_set_encrypt_key, padlock_aes_encrypt,

			    key);

	} else

		return GNUTLS_E_INVALID_REQUEST;

	return 0;

}

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

{

	struct gcm_padlock_aes_ctx *ctx = _ctx;

	if (iv_size != GCM_BLOCK_SIZE - 4)

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	GCM_SET_IV(ctx, iv_size, iv);

	return 0;

}

static int

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

		void *dst, size_t length)

{

	struct gcm_padlock_aes_ctx *ctx = _ctx;

	GCM_ENCRYPT(ctx, padlock_aes_encrypt, src_size, dst, src);

	return 0;

}

static int

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

		void *dst, size_t dst_size)

{

	struct gcm_padlock_aes_ctx *ctx = _ctx;

	GCM_DECRYPT(ctx, padlock_aes_encrypt, src_size, dst, src);

	return 0;

}

static int aes_gcm_auth(void *_ctx, const void *src, size_t src_size)

{

	struct gcm_padlock_aes_ctx *ctx = _ctx;

	GCM_UPDATE(ctx, src_size, src);

	return 0;

}

static void aes_gcm_tag(void *_ctx, void *tag, size_t tagsize)

{

	struct gcm_padlock_aes_ctx *ctx = _ctx;

	GCM_DIGEST(ctx, padlock_aes_encrypt, tagsize, tag);

}

#include "aes-gcm-aead.h"

const gnutls_crypto_cipher_st _gnutls_aes_gcm_padlock = {

	.init = aes_gcm_cipher_init,

	.setkey = aes_gcm_cipher_setkey,

	.setiv = aes_gcm_setiv,

	.encrypt = aes_gcm_encrypt,

	.decrypt = aes_gcm_decrypt,

	.aead_encrypt = aes_gcm_aead_encrypt,

	.aead_decrypt = aes_gcm_aead_decrypt,

	.deinit = aes_gcm_deinit,

	.tag = aes_gcm_tag,

	.auth = aes_gcm_auth,

};

#endif