/*

 * Copyright (C) 2001-2012 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/>

 *

 */

#include "gnutls_int.h"

#include "errors.h"

#include "auth.h"

#include "auth.h"

#include "algorithms.h"

#include <auth/cert.h>

#include <auth/psk.h>

#include <auth/anon.h>

#include <datum.h>

/* The functions here are used in order for authentication algorithms

 * to be able to retrieve the needed credentials eg public and private

 * key etc.

 */

/**

 * gnutls_credentials_clear:

 * @session: is a #gnutls_session_t type.

 *

 * Clears all the credentials previously set in this session.

 **/

void gnutls_credentials_clear(gnutls_session_t session)

{

	if (session->key.cred) {	/* beginning of the list */

		auth_cred_st *ccred, *ncred;

		ccred = session->key.cred;

		while (ccred != NULL) {

			ncred = ccred->next;

			gnutls_free(ccred);

			ccred = ncred;

		}

		session->key.cred = NULL;

	}

}

/* 

 * This creates a linked list of the form:

 * { algorithm, credentials, pointer to next }

 */

/**

 * gnutls_credentials_set:

 * @session: is a #gnutls_session_t type.

 * @type: is the type of the credentials

 * @cred: the credentials to set

 *

 * Sets the needed credentials for the specified type.  E.g. username,

 * password - or public and private keys etc.  The @cred parameter is

 * a structure that depends on the specified type and on the current

 * session (client or server).

 *

 * In order to minimize memory usage, and share credentials between

 * several threads gnutls keeps a pointer to cred, and not the whole

 * cred structure.  Thus you will have to keep the structure allocated

 * until you call gnutls_deinit().

 *

 * For %GNUTLS_CRD_ANON, @cred should be

 * #gnutls_anon_client_credentials_t in case of a client.  In case of

 * a server it should be #gnutls_anon_server_credentials_t.

 *

 * For %GNUTLS_CRD_SRP, @cred should be #gnutls_srp_client_credentials_t

 * in case of a client, and #gnutls_srp_server_credentials_t, in case

 * of a server.

 *

 * For %GNUTLS_CRD_CERTIFICATE, @cred should be

 * #gnutls_certificate_credentials_t.

 *

 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,

 *   otherwise a negative error code is returned.

 **/

int

gnutls_credentials_set(gnutls_session_t session,

		       gnutls_credentials_type_t type, void *cred)

{

	auth_cred_st *ccred = NULL, *pcred = NULL;

	int exists = 0;

	if (session->key.cred == NULL) {	/* beginning of the list */

		session->key.cred = gnutls_malloc(sizeof(auth_cred_st));

		if (session->key.cred == NULL)

			return GNUTLS_E_MEMORY_ERROR;

		/* copy credentials locally */

		session->key.cred->credentials = cred;

		session->key.cred->next = NULL;

		session->key.cred->algorithm = type;

	} else {

		ccred = session->key.cred;

		while (ccred != NULL) {

			if (ccred->algorithm == type) {

				exists = 1;

				break;

			}

			pcred = ccred;

			ccred = ccred->next;

		}

		/* After this, pcred is not null.

		 */

		if (exists == 0) {	/* new entry */

			pcred->next = gnutls_malloc(sizeof(auth_cred_st));

			if (pcred->next == NULL)

				return GNUTLS_E_MEMORY_ERROR;

			ccred = pcred->next;

			/* copy credentials locally */

			ccred->credentials = cred;

			ccred->next = NULL;

			ccred->algorithm = type;

		} else {	/* modify existing entry */

			ccred->credentials = cred;

		}

	}

	/* sanity tests */

	if (type == GNUTLS_CRD_CERTIFICATE) {

		gnutls_certificate_credentials_t c = cred;

		unsigned i;

		bool allow_tls13 = 0;

		unsigned key_usage;

		if (c != NULL && c->ncerts != 0) {

			for (i = 0; i < c->ncerts; i++) {

				key_usage = get_key_usage(session, c->certs[i].cert_list[0].pubkey);

				if (key_usage == 0 || (key_usage & GNUTLS_KEY_DIGITAL_SIGNATURE)) {

					allow_tls13 = 1;

					break;

				}

			}

			if (session->security_parameters.entity == GNUTLS_SERVER &&

			    !c->tls13_ok)

				allow_tls13 = 0;

			if (!allow_tls13) {

				/* to prevent the server random indicate TLS1.3 support */

				session->internals.flags |= INT_FLAG_NO_TLS13;

			}

		}

	}

	return 0;

}

/**

 * gnutls_credentials_get:

 * @session: is a #gnutls_session_t type.

 * @type: is the type of the credentials to return

 * @cred: will contain the credentials.

 *

 * Returns the previously provided credentials structures.

 *

 * For %GNUTLS_CRD_ANON, @cred will be

 * #gnutls_anon_client_credentials_t in case of a client.  In case of

 * a server it should be #gnutls_anon_server_credentials_t.

 *

 * For %GNUTLS_CRD_SRP, @cred will be #gnutls_srp_client_credentials_t

 * in case of a client, and #gnutls_srp_server_credentials_t, in case

 * of a server.

 *

 * For %GNUTLS_CRD_CERTIFICATE, @cred will be

 * #gnutls_certificate_credentials_t.

 *

 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,

 *   otherwise a negative error code is returned.

 *

 * Since: 3.3.3

 **/

int

gnutls_credentials_get(gnutls_session_t session,

		       gnutls_credentials_type_t type, void **cred)

{

	const void *_cred;

	_cred = _gnutls_get_cred(session, type);

	if (_cred == NULL)

		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

	if (cred)

		*cred = (void*)_cred;

	return 0;

}

/**

 * gnutls_auth_get_type:

 * @session: is a #gnutls_session_t type.

 *

 * Returns type of credentials for the current authentication schema.

 * The returned information is to be used to distinguish the function used

 * to access authentication data.

 *

 * Eg. for CERTIFICATE ciphersuites (key exchange algorithms:

 * %GNUTLS_KX_RSA, %GNUTLS_KX_DHE_RSA), the same function are to be

 * used to access the authentication data.

 *

 * Note that on resumed sessions, this function returns the schema

 * used in the original session authentication.

 *

 * Returns: The type of credentials for the current authentication

 *   schema, a #gnutls_credentials_type_t type.

 **/

gnutls_credentials_type_t gnutls_auth_get_type(gnutls_session_t session)

{

	if (session->security_parameters.entity == GNUTLS_SERVER)

		return gnutls_auth_client_get_type(session);

	else

		return gnutls_auth_server_get_type(session);

}

/**

 * gnutls_auth_server_get_type:

 * @session: is a #gnutls_session_t type.

 *

 * Returns the type of credentials that were used for server authentication.

 * The returned information is to be used to distinguish the function used

 * to access authentication data.

 *

 * Note that on resumed sessions, this function returns the schema

 * used in the original session authentication.

 *

 * Returns: The type of credentials for the server authentication

 *   schema, a #gnutls_credentials_type_t type.

 **/

gnutls_credentials_type_t

gnutls_auth_server_get_type(gnutls_session_t session)

{

	return session->security_parameters.server_auth_type;

}

/**

 * gnutls_auth_client_get_type:

 * @session: is a #gnutls_session_t type.

 *

 * Returns the type of credentials that were used for client authentication.

 * The returned information is to be used to distinguish the function used

 * to access authentication data.

 *

 * Note that on resumed sessions, this function returns the schema

 * used in the original session authentication.

 *

 * Returns: The type of credentials for the client authentication

 *   schema, a #gnutls_credentials_type_t type.

 **/

gnutls_credentials_type_t

gnutls_auth_client_get_type(gnutls_session_t session)

{

	return session->security_parameters.client_auth_type;

}

/* 

 * This returns a pointer to the linked list. Don't

 * free that!!!

 */

const void *_gnutls_get_kx_cred(gnutls_session_t session,

				gnutls_kx_algorithm_t algo)

{

	int server =

	    session->security_parameters.entity == GNUTLS_SERVER ? 1 : 0;

	return _gnutls_get_cred(session,

				_gnutls_map_kx_get_cred(algo, server));

}

const void *_gnutls_get_cred(gnutls_session_t session,

			     gnutls_credentials_type_t type)

{

	auth_cred_st *ccred;

	gnutls_key_st *key = &session->key;

	ccred = key->cred;

	while (ccred != NULL) {

		if (ccred->algorithm == type) {

			break;

		}

		ccred = ccred->next;

	}

	if (ccred == NULL)

		return NULL;

	return ccred->credentials;

}

/*-

 * _gnutls_free_auth_info - Frees the auth info structure

 * @session: is a #gnutls_session_t type.

 *

 * This function frees the auth info structure and sets it to

 * null. It must be called since some structures contain malloced

 * elements.

 -*/

void _gnutls_free_auth_info(gnutls_session_t session)

{

	dh_info_st *dh_info;

	if (session == NULL) {

		gnutls_assert();

		return;

	}

	switch (session->key.auth_info_type) {

	case GNUTLS_CRD_SRP:

		break;

#ifdef ENABLE_ANON

	case GNUTLS_CRD_ANON:

		{

			anon_auth_info_t info =

			    _gnutls_get_auth_info(session, GNUTLS_CRD_ANON);

			if (info == NULL)

				break;

			dh_info = &info->dh;

			_gnutls_free_dh_info(dh_info);

		}

		break;

#endif

	case GNUTLS_CRD_PSK:

		{

			psk_auth_info_t info =

			    _gnutls_get_auth_info(session, GNUTLS_CRD_PSK);

			if (info == NULL)

				break;

#ifdef ENABLE_DHE

			dh_info = &info->dh;

			_gnutls_free_dh_info(dh_info);

#endif

		}

		break;

	case GNUTLS_CRD_CERTIFICATE:

		{

			unsigned int i;

			cert_auth_info_t info =

			    _gnutls_get_auth_info(session, GNUTLS_CRD_CERTIFICATE);

			if (info == NULL)

				break;

			dh_info = &info->dh;

			for (i = 0; i < info->ncerts; i++) {

				_gnutls_free_datum(&info->raw_certificate_list[i]);

			}

			for (i = 0; i < info->nocsp; i++) {

				_gnutls_free_datum(&info->raw_ocsp_list[i]);

			}

			gnutls_free(info->raw_certificate_list);

			gnutls_free(info->raw_ocsp_list);

			info->ncerts = 0;

			info->nocsp = 0;

#ifdef ENABLE_DHE

			_gnutls_free_dh_info(dh_info);

#endif

		}

		break;

	default:

		return;

	}

	gnutls_free(session->key.auth_info);

	session->key.auth_info_size = 0;

	session->key.auth_info_type = 0;

}

/* This function will create the auth info structure in the key

 * structure if needed.

 *

 * If allow change is !=0 then this will allow changing the auth

 * info structure to a different type.

 */

int

_gnutls_auth_info_init(gnutls_session_t session,

		      gnutls_credentials_type_t type, int size,

		      int allow_change)

{

	if (session->key.auth_info == NULL) {

		session->key.auth_info = gnutls_calloc(1, size);

		if (session->key.auth_info == NULL) {

			gnutls_assert();

			return GNUTLS_E_MEMORY_ERROR;

		}

		session->key.auth_info_type = type;

		session->key.auth_info_size = size;

	} else {

		if (allow_change == 0) {

			/* If the credentials for the current authentication scheme,

			 * are not the one we want to set, then it's an error.

			 * This may happen if a rehandshake is performed an the

			 * ciphersuite which is negotiated has different authentication

			 * schema.

			 */

			if (type != session->key.auth_info_type) {

				gnutls_assert();

				return GNUTLS_E_INVALID_REQUEST;

			}

		} else {

			/* The new behaviour: Here we reallocate the auth info structure

			 * in order to be able to negotiate different authentication

			 * types. Ie. perform an auth_anon and then authenticate again using a

			 * certificate (in order to prevent revealing the certificate's contents,

			 * to passive eavesdropers.

			 */

			if (type != session->key.auth_info_type) {

				_gnutls_free_auth_info(session);

				session->key.auth_info = calloc(1, size);

				if (session->key.auth_info == NULL) {

					gnutls_assert();

					return GNUTLS_E_MEMORY_ERROR;

				}

				session->key.auth_info_type = type;

				session->key.auth_info_size = size;

			}

		}

	}

	return 0;

}