/*

 * Copyright (C) 2000-2012 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 <http://www.gnu.org/licenses/>

 *

 */

/* This file handles all the internal functions that cope with hashes

 * and HMACs.

 */

#include "gnutls_int.h"

#include <hash_int.h>

#include "errors.h"

#include <algorithms.h>

#include <fips.h>

int _gnutls_hash_init(digest_hd_st * dig, const mac_entry_st * e)

{

	int result;

	const gnutls_crypto_digest_st *cc = NULL;

	FAIL_IF_LIB_ERROR;

	if (unlikely(e == NULL || e->id == GNUTLS_MAC_NULL))

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	dig->e = e;

	/* check if a digest has been registered 

	 */

	cc = _gnutls_get_crypto_digest((gnutls_digest_algorithm_t)e->id);

	if (cc != NULL && cc->init) {

		if (cc->init((gnutls_digest_algorithm_t)e->id, &dig->handle) < 0) {

			gnutls_assert();

			return GNUTLS_E_HASH_FAILED;

		}

		dig->hash = cc->hash;

		dig->output = cc->output;

		dig->deinit = cc->deinit;

		return 0;

	}

	result = _gnutls_digest_ops.init((gnutls_digest_algorithm_t)e->id, &dig->handle);

	if (result < 0) {

		gnutls_assert();

		return result;

	}

	dig->hash = _gnutls_digest_ops.hash;

	dig->output = _gnutls_digest_ops.output;

	dig->deinit = _gnutls_digest_ops.deinit;

	return 0;

}

/* Returns true(non-zero) or false(0) if the 

 * provided hash exists

 */

int _gnutls_digest_exists(gnutls_digest_algorithm_t algo)

{

	const gnutls_crypto_digest_st *cc = NULL;

	cc = _gnutls_get_crypto_digest(algo);

	if (cc != NULL)

		return 1;

	return _gnutls_digest_ops.exists(algo);

}

void _gnutls_hash_deinit(digest_hd_st * handle, void *digest)

{

	if (handle->handle == NULL) {

		return;

	}

	if (digest != NULL)

		_gnutls_hash_output(handle, digest);

	handle->deinit(handle->handle);

	handle->handle = NULL;

}

int

_gnutls_hash_fast(gnutls_digest_algorithm_t algorithm,

		  const void *text, size_t textlen, void *digest)

{

	int ret;

	const gnutls_crypto_digest_st *cc = NULL;

	FAIL_IF_LIB_ERROR;

	/* check if a digest has been registered 

	 */

	cc = _gnutls_get_crypto_digest(algorithm);

	if (cc != NULL) {

		if (cc->fast(algorithm, text, textlen, digest) < 0) {

			gnutls_assert();

			return GNUTLS_E_HASH_FAILED;

		}

		return 0;

	}

	ret = _gnutls_digest_ops.fast(algorithm, text, textlen, digest);

	if (ret < 0) {

		gnutls_assert();

		return ret;

	}

	return 0;

}

/* HMAC interface */

int

_gnutls_mac_fast(gnutls_mac_algorithm_t algorithm, const void *key,

		 int keylen, const void *text, size_t textlen,

		 void *digest)

{

	int ret;

	const gnutls_crypto_mac_st *cc = NULL;

	FAIL_IF_LIB_ERROR;

	/* check if a digest has been registered 

	 */

	cc = _gnutls_get_crypto_mac(algorithm);

	if (cc != NULL) {

		if (cc->

		    fast(algorithm, NULL, 0, key, keylen, text, textlen,

			 digest) < 0) {

			gnutls_assert();

			return GNUTLS_E_HASH_FAILED;

		}

		return 0;

	}

	ret =

	    _gnutls_mac_ops.fast(algorithm, NULL, 0, key, keylen, text,

				 textlen, digest);

	if (ret < 0) {

		gnutls_assert();

		return ret;

	}

	return 0;

}

/* Returns true(non-zero) or false(0) if the 

 * provided hash exists

 */

int _gnutls_mac_exists(gnutls_mac_algorithm_t algo)

{

	const gnutls_crypto_mac_st *cc = NULL;

	/* exceptionally it exists, as it is not a real MAC */

	if (algo == GNUTLS_MAC_AEAD)

		return 1;

	cc = _gnutls_get_crypto_mac(algo);

	if (cc != NULL)

		return 1;

	return _gnutls_mac_ops.exists(algo);

}

int

_gnutls_mac_init(mac_hd_st * mac, const mac_entry_st * e,

		 const void *key, int keylen)

{

	int result;

	const gnutls_crypto_mac_st *cc = NULL;

	FAIL_IF_LIB_ERROR;

	if (unlikely(e == NULL || e->id == GNUTLS_MAC_NULL))

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	mac->e = e;

	mac->mac_len = _gnutls_mac_get_algo_len(e);

	/* check if a digest has been registered 

	 */

	cc = _gnutls_get_crypto_mac(e->id);

	if (cc != NULL && cc->init != NULL) {

		if (cc->init(e->id, &mac->handle) < 0) {

			gnutls_assert();

			return GNUTLS_E_HASH_FAILED;

		}

		if (cc->setkey(mac->handle, key, keylen) < 0) {

			gnutls_assert();

			cc->deinit(mac->handle);

			return GNUTLS_E_HASH_FAILED;

		}

		mac->hash = cc->hash;

		mac->setnonce = cc->setnonce;

		mac->output = cc->output;

		mac->deinit = cc->deinit;

		return 0;

	}

	result = _gnutls_mac_ops.init(e->id, &mac->handle);

	if (result < 0) {

		gnutls_assert();

		return result;

	}

	mac->hash = _gnutls_mac_ops.hash;

	mac->setnonce = _gnutls_mac_ops.setnonce;

	mac->output = _gnutls_mac_ops.output;

	mac->deinit = _gnutls_mac_ops.deinit;

	if (_gnutls_mac_ops.setkey(mac->handle, key, keylen) < 0) {

		gnutls_assert();

		mac->deinit(mac->handle);

		return GNUTLS_E_HASH_FAILED;

	}

	return 0;

}

void _gnutls_mac_deinit(mac_hd_st * handle, void *digest)

{

	if (handle->handle == NULL) {

		return;

	}

	if (digest)

		_gnutls_mac_output(handle, digest);

	handle->deinit(handle->handle);

	handle->handle = NULL;

}

#ifdef ENABLE_SSL3

inline static int get_padsize(gnutls_mac_algorithm_t algorithm)

{

	switch (algorithm) {

	case GNUTLS_MAC_MD5:

		return 48;

	case GNUTLS_MAC_SHA1:

		return 40;

	default:

		return 0;

	}

}

/* Special functions for SSL3 MAC

 */

int

_gnutls_mac_init_ssl3(digest_hd_st * ret, const mac_entry_st * e,

		      void *key, int keylen)

{

	uint8_t ipad[48];

	int padsize, result;

	FAIL_IF_LIB_ERROR;

	padsize = get_padsize(e->id);

	if (padsize == 0) {

		gnutls_assert();

		return GNUTLS_E_HASH_FAILED;

	}

	memset(ipad, 0x36, padsize);

	result = _gnutls_hash_init(ret, e);

	if (result < 0) {

		gnutls_assert();

		return result;

	}

	ret->key = key;

	ret->keysize = keylen;

	if (keylen > 0)

		_gnutls_hash(ret, key, keylen);

	_gnutls_hash(ret, ipad, padsize);

	return 0;

}

int _gnutls_mac_output_ssl3(digest_hd_st * handle, void *digest)

{

	uint8_t ret[MAX_HASH_SIZE];

	digest_hd_st td;

	uint8_t opad[48];

	int padsize;

	int block, rc;

	padsize = get_padsize(handle->e->id);

	if (padsize == 0) {

		gnutls_assert();

		return GNUTLS_E_INTERNAL_ERROR;

	}

	memset(opad, 0x5C, padsize);

	rc = _gnutls_hash_init(&td, handle->e);

	if (rc < 0) {

		gnutls_assert();

		return rc;

	}

	if (handle->keysize > 0)

		_gnutls_hash(&td, handle->key, handle->keysize);

	_gnutls_hash(&td, opad, padsize);

	block = _gnutls_mac_get_algo_len(handle->e);

	_gnutls_hash_output(handle, ret);	/* get the previous hash */

	_gnutls_hash(&td, ret, block);

	_gnutls_hash_deinit(&td, digest);

	/* reset handle */

	memset(opad, 0x36, padsize);

	if (handle->keysize > 0)

		_gnutls_hash(handle, handle->key, handle->keysize);

	_gnutls_hash(handle, opad, padsize);

	return 0;

}

int _gnutls_mac_deinit_ssl3(digest_hd_st * handle, void *digest)

{

	int ret = 0;

	if (digest != NULL)

		ret = _gnutls_mac_output_ssl3(handle, digest);

	_gnutls_hash_deinit(handle, NULL);

	return ret;

}

int

_gnutls_mac_deinit_ssl3_handshake(digest_hd_st * handle,

				  void *digest, uint8_t * key,

				  uint32_t key_size)

{

	uint8_t ret[MAX_HASH_SIZE];

	digest_hd_st td;

	uint8_t opad[48];

	uint8_t ipad[48];

	int padsize;

	int block, rc;

	padsize = get_padsize(handle->e->id);

	if (padsize == 0) {

		gnutls_assert();

		rc = GNUTLS_E_INTERNAL_ERROR;

		goto cleanup;

	}

	memset(opad, 0x5C, padsize);

	memset(ipad, 0x36, padsize);

	rc = _gnutls_hash_init(&td, handle->e);

	if (rc < 0) {

		gnutls_assert();

		goto cleanup;

	}

	if (key_size > 0)

		_gnutls_hash(&td, key, key_size);

	_gnutls_hash(&td, opad, padsize);

	block = _gnutls_mac_get_algo_len(handle->e);

	if (key_size > 0)

		_gnutls_hash(handle, key, key_size);

	_gnutls_hash(handle, ipad, padsize);

	_gnutls_hash_deinit(handle, ret);	/* get the previous hash */

	_gnutls_hash(&td, ret, block);

	_gnutls_hash_deinit(&td, digest);

	return 0;

      cleanup:

	_gnutls_hash_deinit(handle, NULL);

	return rc;

}

static int

ssl3_sha(int i, uint8_t * secret, int secret_len,

	 uint8_t * rnd, int rnd_len, void *digest)

{

	int j, ret;

	uint8_t text1[26];

	digest_hd_st td;

	for (j = 0; j < i + 1; j++) {

		text1[j] = 65 + i;	/* A==65 */

	}

	ret = _gnutls_hash_init(&td, mac_to_entry(GNUTLS_MAC_SHA1));

	if (ret < 0) {

		gnutls_assert();

		return ret;

	}

	_gnutls_hash(&td, text1, i + 1);

	_gnutls_hash(&td, secret, secret_len);

	_gnutls_hash(&td, rnd, rnd_len);

	_gnutls_hash_deinit(&td, digest);

	return 0;

}

#define SHA1_DIGEST_OUTPUT 20

#define MD5_DIGEST_OUTPUT 16

static int

ssl3_md5(int i, uint8_t * secret, int secret_len,

	 uint8_t * rnd, int rnd_len, void *digest)

{

	uint8_t tmp[MAX_HASH_SIZE];

	digest_hd_st td;

	int ret;

	ret = _gnutls_hash_init(&td, mac_to_entry(GNUTLS_MAC_MD5));

	if (ret < 0) {

		gnutls_assert();

		return ret;

	}

	_gnutls_hash(&td, secret, secret_len);

	ret = ssl3_sha(i, secret, secret_len, rnd, rnd_len, tmp);

	if (ret < 0) {

		gnutls_assert();

		_gnutls_hash_deinit(&td, digest);

		return ret;

	}

	_gnutls_hash(&td, tmp, SHA1_DIGEST_OUTPUT);

	_gnutls_hash_deinit(&td, digest);

	return 0;

}

int

_gnutls_ssl3_generate_random(void *secret, int secret_len,

			     void *rnd, int rnd_len,

			     int ret_bytes, uint8_t * ret)

{

	int i = 0, copy, output_bytes;

	uint8_t digest[MAX_HASH_SIZE];

	int block = MD5_DIGEST_OUTPUT;

	int result, times;

	output_bytes = 0;

	do {

		output_bytes += block;

	}

	while (output_bytes < ret_bytes);

	times = output_bytes / block;

	for (i = 0; i < times; i++) {

		result =

		    ssl3_md5(i, secret, secret_len, rnd, rnd_len, digest);

		if (result < 0) {

			gnutls_assert();

			return result;

		}

		if ((1 + i) * block < ret_bytes) {

			copy = block;

		} else {

			copy = ret_bytes - (i) * block;

		}

		memcpy(&ret[i * block], digest, copy);

	}

	return 0;

}

#endif