/*

 * Copyright (C) 2000-2012 Free Software Foundation, Inc.

 * Copyright (C) 2017 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/>

 *

 */

#ifndef GNUTLS_LIB_ALGORITHMS_H

#define GNUTLS_LIB_ALGORITHMS_H

#include "auth.h"

#ifdef DISABLE_SYSTEM_CONFIG

# define SYSTEM_CONFIG_OR_CONST const

#else

# define SYSTEM_CONFIG_OR_CONST

#endif

#define version_to_entry _gnutls_version_to_entry

#define GNUTLS_RENEGO_PROTECTION_REQUEST_MAJOR 0x00

#define GNUTLS_RENEGO_PROTECTION_REQUEST_MINOR 0xFF

#define GNUTLS_FALLBACK_SCSV_MAJOR 0x56

#define GNUTLS_FALLBACK_SCSV_MINOR 0x00

#define IS_GOSTEC(x) (((x)==GNUTLS_PK_GOST_01)	|| \

		      ((x)==GNUTLS_PK_GOST_12_256)|| \

		      ((x)==GNUTLS_PK_GOST_12_512))

#define IS_EC(x) (((x)==GNUTLS_PK_ECDSA)|| \

		  ((x)==GNUTLS_PK_ECDH_X25519)||((x)==GNUTLS_PK_EDDSA_ED25519)|| \

		  ((x)==GNUTLS_PK_ECDH_X448)||((x)==GNUTLS_PK_EDDSA_ED448))

#define SIG_SEM_PRE_TLS12 (1<<1)

#define SIG_SEM_TLS13 (1<<2)

#define SIG_SEM_DEFAULT (SIG_SEM_PRE_TLS12|SIG_SEM_TLS13)

#define TLS_SIGN_AID_UNKNOWN {{255, 255}, 0}

#define HAVE_UNKNOWN_SIGAID(aid) ((aid)->id[0] == 255 && (aid)->id[1] == 255)

#define CS_INVALID_MAJOR 0x00

#define CS_INVALID_MINOR 0x00

/* Functions for version handling. */

const version_entry_st *version_to_entry(gnutls_protocol_t version);

const version_entry_st *nversion_to_entry(uint8_t major, uint8_t minor);

const version_entry_st *_gnutls_version_lowest(gnutls_session_t session);

const version_entry_st *_gnutls_legacy_version_max(gnutls_session_t session);

const version_entry_st *_gnutls_version_max(gnutls_session_t session);

int _gnutls_version_priority(gnutls_session_t session,

			     gnutls_protocol_t version);

int _gnutls_nversion_is_supported(gnutls_session_t session,

				  unsigned char major, unsigned char minor);

gnutls_protocol_t _gnutls_version_get(uint8_t major, uint8_t minor);

unsigned _gnutls_version_is_too_high(gnutls_session_t session, uint8_t major, uint8_t minor);

int _gnutls_write_supported_versions(gnutls_session_t session, uint8_t *buffer, ssize_t buffer_size);

/* Functions for feature checks */

int

_gnutls_figure_common_ciphersuite(gnutls_session_t session,

				  const ciphersuite_list_st *peer_clist,

				  const gnutls_cipher_suite_entry_st **ce);

inline static int

_gnutls_version_has_selectable_prf(const version_entry_st * ver)

{

	if (unlikely(ver == NULL))

		return 0;

	return ver->selectable_prf;

}

inline static int

_gnutls_version_has_selectable_sighash(const version_entry_st * ver)

{

	if (unlikely(ver == NULL))

		return 0;

	return ver->selectable_sighash;

}

inline static

int _gnutls_version_has_extensions(const version_entry_st * ver)

{

	if (unlikely(ver == NULL))

		return 0;

	return ver->extensions;

}

inline static

int _gnutls_version_has_explicit_iv(const version_entry_st * ver)

{

	if (unlikely(ver == NULL))

		return 0;

	return ver->explicit_iv;

}

/* Functions for MACs. */

const mac_entry_st *_gnutls_mac_to_entry(gnutls_mac_algorithm_t c);

#define mac_to_entry(x) _gnutls_mac_to_entry(x)

#define hash_to_entry(x) mac_to_entry((gnutls_mac_algorithm_t)(x))

inline static int _gnutls_mac_is_ok(const mac_entry_st * e)

{

	if (unlikely(e == NULL) || e->id == 0)

		return 0;

	else

		return 1;

}

/*-

 * _gnutls_mac_get_algo_len:

 * @algorithm: is an encryption algorithm

 *

 * Get size of MAC key.

 *

 * Returns: length (in bytes) of the MAC output size, or 0 if the

 *   given MAC algorithm is invalid.

 -*/

inline static size_t _gnutls_mac_get_algo_len(const mac_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	else

		return e->output_size;

}

inline static const char *_gnutls_x509_mac_to_oid(const mac_entry_st * e)

{

	if (unlikely(e == NULL))

		return NULL;

	else

		return e->oid;

}

inline static const char *_gnutls_mac_get_name(const mac_entry_st * e)

{

	if (unlikely(e == NULL))

		return NULL;

	else

		return e->name;

}

inline static int _gnutls_mac_block_size(const mac_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	else

		return e->block_size;

}

inline static int _gnutls_mac_get_key_size(const mac_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	else

		return e->key_size;

}

/* Functions for digests. */

#define _gnutls_x509_digest_to_oid _gnutls_x509_mac_to_oid

#define _gnutls_digest_get_name _gnutls_mac_get_name

#define _gnutls_hash_get_algo_len _gnutls_mac_get_algo_len

/* Security against pre-image attacks */

inline static int _gnutls_digest_is_secure(const mac_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	else

		return !(e->flags & GNUTLS_MAC_FLAG_PREIMAGE_INSECURE);

}

/* Functions for cipher suites. */

int _gnutls_get_client_ciphersuites(gnutls_session_t session,

	gnutls_buffer_st * cdata, const version_entry_st *minver,

	unsigned add_scsv);

int _gnutls_supported_ciphersuites(gnutls_session_t session,

				   uint8_t * cipher_suites,

				   unsigned int max_cipher_suite_size);

const gnutls_cipher_suite_entry_st

    *cipher_suite_get(gnutls_kx_algorithm_t kx_algorithm,

		      gnutls_cipher_algorithm_t cipher_algorithm,

		      gnutls_mac_algorithm_t mac_algorithm);

const char *_gnutls_cipher_suite_get_name(const uint8_t suite[2]);

gnutls_kx_algorithm_t _gnutls_cipher_suite_get_kx_algo(const uint8_t

						       suite[2]);

int

_gnutls_cipher_suite_get_id(gnutls_kx_algorithm_t kx_algorithm,

			    gnutls_cipher_algorithm_t cipher_algorithm,

			    gnutls_mac_algorithm_t mac_algorithm,

			    uint8_t suite[2]);

const gnutls_cipher_suite_entry_st *ciphersuite_to_entry(const uint8_t suite[2]);

/* Functions for ciphers. */

const cipher_entry_st *_gnutls_cipher_to_entry(gnutls_cipher_algorithm_t c);

#define cipher_to_entry(x) _gnutls_cipher_to_entry(x)

const cipher_entry_st *cipher_name_to_entry(const char *name);

inline static cipher_type_t _gnutls_cipher_type(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return CIPHER_AEAD; /* doesn't matter */

	return e->type;

}

inline static int _gnutls_cipher_get_block_size(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	return e->blocksize;

}

inline static int

_gnutls_cipher_get_implicit_iv_size(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	return e->implicit_iv;

}

inline static int

_gnutls_cipher_get_iv_size(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	return e->cipher_iv;

}

inline static int

_gnutls_cipher_get_explicit_iv_size(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	return e->explicit_iv;

}

inline static int _gnutls_cipher_get_key_size(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	return e->keysize;

}

inline static const char *_gnutls_cipher_get_name(const cipher_entry_st *

						  e)

{

	if (unlikely(e == NULL))

		return NULL;

	return e->name;

}

inline static int _gnutls_cipher_algo_is_aead(const cipher_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	return (e->type == CIPHER_AEAD)?1:0;

}

inline static int _gnutls_cipher_is_ok(const cipher_entry_st * e)

{

	if (unlikely(e == NULL) || e->id == 0)

		return 0;

	else

		return 1;

}

inline static int _gnutls_cipher_get_tag_size(const cipher_entry_st * e)

{

	size_t ret = 0;

	if (unlikely(e == NULL))

		return ret;

	/* non-AEAD have 0 as tag size */

	return e->tagsize;

}

/* Functions for key exchange. */

bool _gnutls_kx_needs_dh_params(gnutls_kx_algorithm_t algorithm);

bool _gnutls_kx_allows_false_start(gnutls_session_t session);

mod_auth_st *_gnutls_kx_auth_struct(gnutls_kx_algorithm_t algorithm);

int _gnutls_kx_is_ok(gnutls_kx_algorithm_t algorithm);

int _gnutls_kx_get_id(const char *name);

gnutls_credentials_type_t _gnutls_map_kx_get_cred(gnutls_kx_algorithm_t

						  algorithm, int server);

/* KX to PK mapping. */

unsigned

_gnutls_kx_supports_pk(gnutls_kx_algorithm_t kx_algorithm,

		       gnutls_pk_algorithm_t pk_algorithm);

unsigned

_gnutls_kx_supports_pk_usage(gnutls_kx_algorithm_t kx_algorithm,

		       gnutls_pk_algorithm_t pk_algorithm,

		       unsigned key_usage);

enum encipher_type { CIPHER_ENCRYPT = 0, CIPHER_SIGN = 1, CIPHER_IGN };

enum encipher_type _gnutls_kx_encipher_type(gnutls_kx_algorithm_t

					    kx_algorithm);

/* Functions for sign algorithms. */

typedef enum hash_security_level_t {

	_SECURE,

	_INSECURE_FOR_CERTS,

	_INSECURE

} hash_security_level_t;

int _gnutls_ecc_curve_mark_disabled(const char *name);

int _gnutls_sign_mark_insecure(const char *name, hash_security_level_t);

int _gnutls_digest_mark_insecure(const char *name);

unsigned _gnutls_digest_is_insecure(gnutls_digest_algorithm_t dig);

int _gnutls_version_mark_disabled(const char *name);

gnutls_protocol_t _gnutls_protocol_get_id_if_supported(const char *name);

#define GNUTLS_SIGN_FLAG_TLS13_OK	1 /* if it is ok to use under TLS1.3 */

#define GNUTLS_SIGN_FLAG_CRT_VRFY_REVERSE (1 << 1) /* reverse order of bytes in CrtVrfy signature */

struct gnutls_sign_entry_st {

	const char *name;

	const char *oid;

	gnutls_sign_algorithm_t id;

	gnutls_pk_algorithm_t pk;

	gnutls_digest_algorithm_t hash;

	/* if non-zero it must be the algorithm of the

	 * private key used or certificate. This is for algorithms

	 * which can have a different public key type than the

	 * private key (e.g., RSA PKCS#1 1.5 certificate, but

	 * an RSA-PSS private key, or an RSA private key and

	 * an RSA-PSS certificate). */

	gnutls_pk_algorithm_t priv_pk;

	gnutls_pk_algorithm_t cert_pk;

	unsigned flags;

	/* if this signature algorithm is restricted to a curve

	 * under TLS 1.3. */

	gnutls_ecc_curve_t curve;

	/* See RFC 5246 HashAlgorithm and SignatureAlgorithm

	   for values to use in aid struct. */

	const sign_algorithm_st aid;

	hash_security_level_t slevel;	/* contains values of hash_security_level_t */

	/* 0 if it matches the predefined hash output size, otherwise

	 * it is truncated or expanded (with XOF) */

	unsigned hash_output_size;

};

typedef struct gnutls_sign_entry_st gnutls_sign_entry_st;

const gnutls_sign_entry_st *_gnutls_sign_to_entry(gnutls_sign_algorithm_t sign);

const gnutls_sign_entry_st *_gnutls_pk_to_sign_entry(gnutls_pk_algorithm_t pk, gnutls_digest_algorithm_t hash);

const gnutls_sign_entry_st *_gnutls_oid_to_sign_entry(const char *oid);

/* returns true if that signature can be generated

 * from the given private key algorithm. */

inline static unsigned

sign_supports_priv_pk_algorithm(const gnutls_sign_entry_st *se, gnutls_pk_algorithm_t pk)

{

	if (pk == se->pk || (se->priv_pk && se->priv_pk == pk))

		return 1;

	return 0;

}

/* returns true if that signature can be verified with

 * the given public key algorithm. */

inline static unsigned

sign_supports_cert_pk_algorithm(const gnutls_sign_entry_st *se, gnutls_pk_algorithm_t pk)

{

	if ((!se->cert_pk && pk == se->pk) || (se->cert_pk && se->cert_pk == pk))

		return 1;

	return 0;

}

bool _gnutls_sign_is_secure2(const gnutls_sign_entry_st *se, unsigned int flags);

gnutls_pk_algorithm_t _gnutls_x509_sign_to_pk(gnutls_sign_algorithm_t

					      sign);

const char *_gnutls_x509_sign_to_oid(gnutls_pk_algorithm_t,

				     gnutls_digest_algorithm_t mac);

const gnutls_sign_entry_st *

_gnutls_tls_aid_to_sign_entry(uint8_t id0, uint8_t id1, const version_entry_st *ver);

gnutls_sign_algorithm_t

_gnutls_tls_aid_to_sign(uint8_t id0, uint8_t id1, const version_entry_st *ver);

const sign_algorithm_st *_gnutls_sign_to_tls_aid(gnutls_sign_algorithm_t

						 sign);

const gnutls_sign_entry_st *

_gnutls13_sign_get_compatible_with_privkey(gnutls_privkey_t privkey);

unsigned int _gnutls_pk_bits_to_subgroup_bits(unsigned int pk_bits);

gnutls_digest_algorithm_t _gnutls_pk_bits_to_sha_hash(unsigned int pk_bits);

gnutls_digest_algorithm_t _gnutls_hash_size_to_sha_hash(unsigned int size);

bool _gnutls_pk_is_not_prehashed(gnutls_pk_algorithm_t algorithm);

/* ECC */

typedef struct gnutls_ecc_curve_entry_st {

	const char *name;

	const char *oid;

	gnutls_ecc_curve_t id;

	gnutls_pk_algorithm_t pk;

	unsigned size;		/* the size in bytes */

	unsigned sig_size;	/* the size of curve signatures in bytes (EdDSA) */

	unsigned gost_curve;

	bool supported;

	gnutls_group_t group;

} gnutls_ecc_curve_entry_st;

const gnutls_ecc_curve_entry_st

    *_gnutls_ecc_curve_get_params(gnutls_ecc_curve_t curve);

unsigned _gnutls_ecc_curve_is_supported(gnutls_ecc_curve_t);

gnutls_group_t _gnutls_ecc_curve_get_group(gnutls_ecc_curve_t);

const gnutls_group_entry_st *_gnutls_tls_id_to_group(unsigned num);

const gnutls_group_entry_st * _gnutls_id_to_group(unsigned id);

gnutls_ecc_curve_t _gnutls_ecc_bits_to_curve(gnutls_pk_algorithm_t pk, int bits);

#define MAX_ECC_CURVE_SIZE 66

gnutls_pk_algorithm_t _gnutls_oid_to_pk_and_curve(const char *oid, gnutls_ecc_curve_t *curve);

inline static int _curve_is_eddsa(const gnutls_ecc_curve_entry_st * e)

{

	if (unlikely(e == NULL))

		return 0;

	if (e->pk == GNUTLS_PK_EDDSA_ED25519 ||

	    e->pk == GNUTLS_PK_EDDSA_ED448)

		return 1;

	return 0;

}

inline static int curve_is_eddsa(gnutls_ecc_curve_t id)

{

	const gnutls_ecc_curve_entry_st *e = _gnutls_ecc_curve_get_params(id);

	return _curve_is_eddsa(e);

}

static inline int _gnutls_kx_is_ecc(gnutls_kx_algorithm_t kx)

{

	if (kx == GNUTLS_KX_ECDHE_RSA || kx == GNUTLS_KX_ECDHE_ECDSA ||

	    kx == GNUTLS_KX_ANON_ECDH || kx == GNUTLS_KX_ECDHE_PSK)

		return 1;

	return 0;

}

static inline int _gnutls_kx_is_psk(gnutls_kx_algorithm_t kx)

{

	if (kx == GNUTLS_KX_PSK || kx == GNUTLS_KX_DHE_PSK ||

	    kx == GNUTLS_KX_ECDHE_PSK || kx == GNUTLS_KX_RSA_PSK)

		return 1;

	return 0;

}

static inline int _gnutls_kx_is_dhe(gnutls_kx_algorithm_t kx)

{

	if (kx == GNUTLS_KX_DHE_RSA || kx == GNUTLS_KX_DHE_DSS ||

	    kx == GNUTLS_KX_ANON_DH || kx == GNUTLS_KX_DHE_PSK)

		return 1;

	return 0;

}

static inline unsigned _gnutls_kx_is_vko_gost(gnutls_kx_algorithm_t kx)

{

	if (kx == GNUTLS_KX_VKO_GOST_12)

		return 1;

	return 0;

}

static inline bool

_sign_is_gost(const gnutls_sign_entry_st *se)

{

	gnutls_pk_algorithm_t pk = se->pk;

	return  (pk == GNUTLS_PK_GOST_01) ||

		(pk == GNUTLS_PK_GOST_12_256) ||

		(pk == GNUTLS_PK_GOST_12_512);

}

static inline int _sig_is_ecdsa(gnutls_sign_algorithm_t sig)

{

	if (sig == GNUTLS_SIGN_ECDSA_SHA1 || sig == GNUTLS_SIGN_ECDSA_SHA224 ||

	    sig == GNUTLS_SIGN_ECDSA_SHA256 || sig == GNUTLS_SIGN_ECDSA_SHA384 ||

	    sig == GNUTLS_SIGN_ECDSA_SHA512)

		return 1;

	return 0;

}

bool _gnutls_pk_are_compat(gnutls_pk_algorithm_t pk1, gnutls_pk_algorithm_t pk2);

unsigned _gnutls_sign_get_hash_strength(gnutls_sign_algorithm_t sign);

#endif /* GNUTLS_LIB_ALGORITHMS_H */