/* * Interface to code from Project Everest * * Copyright 2016-2018 INRIA and Microsoft Corporation * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * This file is part of Mbed TLS (https://tls.mbed.org). */ #ifndef MBEDTLS_EVEREST_H #define MBEDTLS_EVEREST_H #include "everest/x25519.h" #ifdef __cplusplus extern "C" { #endif /** * Defines the source of the imported EC key. */ typedef enum { MBEDTLS_EVEREST_ECDH_OURS, /**< Our key. */ MBEDTLS_EVEREST_ECDH_THEIRS, /**< The key of the peer. */ } mbedtls_everest_ecdh_side; typedef struct { mbedtls_x25519_context ctx; } mbedtls_ecdh_context_everest; /** * \brief This function sets up the ECDH context with the information * given. * * This function should be called after mbedtls_ecdh_init() but * before mbedtls_ecdh_make_params(). There is no need to call * this function before mbedtls_ecdh_read_params(). * * This is the first function used by a TLS server for ECDHE * ciphersuites. * * \param ctx The ECDH context to set up. * \param grp_id The group id of the group to set up the context for. * * \return \c 0 on success. */ int mbedtls_everest_setup( mbedtls_ecdh_context_everest *ctx, int grp_id ); /** * \brief This function frees a context. * * \param ctx The context to free. */ void mbedtls_everest_free( mbedtls_ecdh_context_everest *ctx ); /** * \brief This function generates a public key and a TLS * ServerKeyExchange payload. * * This is the second function used by a TLS server for ECDHE * ciphersuites. (It is called after mbedtls_ecdh_setup().) * * \note This function assumes that the ECP group (grp) of the * \p ctx context has already been properly set, * for example, using mbedtls_ecp_group_load(). * * \see ecp.h * * \param ctx The ECDH context. * \param olen The number of characters written. * \param buf The destination buffer. * \param blen The length of the destination buffer. * \param f_rng The RNG function. * \param p_rng The RNG context. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. */ int mbedtls_everest_make_params( mbedtls_ecdh_context_everest *ctx, size_t *olen, unsigned char *buf, size_t blen, int( *f_rng )( void *, unsigned char *, size_t ), void *p_rng ); /** * \brief This function parses and processes a TLS ServerKeyExhange * payload. * * This is the first function used by a TLS client for ECDHE * ciphersuites. * * \see ecp.h * * \param ctx The ECDH context. * \param buf The pointer to the start of the input buffer. * \param end The address for one Byte past the end of the buffer. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. * */ int mbedtls_everest_read_params( mbedtls_ecdh_context_everest *ctx, const unsigned char **buf, const unsigned char *end ); /** * \brief This function parses and processes a TLS ServerKeyExhange * payload. * * This is the first function used by a TLS client for ECDHE * ciphersuites. * * \see ecp.h * * \param ctx The ECDH context. * \param buf The pointer to the start of the input buffer. * \param end The address for one Byte past the end of the buffer. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. * */ int mbedtls_everest_read_params( mbedtls_ecdh_context_everest *ctx, const unsigned char **buf, const unsigned char *end ); /** * \brief This function sets up an ECDH context from an EC key. * * It is used by clients and servers in place of the * ServerKeyEchange for static ECDH, and imports ECDH * parameters from the EC key information of a certificate. * * \see ecp.h * * \param ctx The ECDH context to set up. * \param key The EC key to use. * \param side Defines the source of the key: 1: Our key, or * 0: The key of the peer. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. * */ int mbedtls_everest_get_params( mbedtls_ecdh_context_everest *ctx, const mbedtls_ecp_keypair *key, mbedtls_everest_ecdh_side side ); /** * \brief This function generates a public key and a TLS * ClientKeyExchange payload. * * This is the second function used by a TLS client for ECDH(E) * ciphersuites. * * \see ecp.h * * \param ctx The ECDH context. * \param olen The number of Bytes written. * \param buf The destination buffer. * \param blen The size of the destination buffer. * \param f_rng The RNG function. * \param p_rng The RNG context. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. */ int mbedtls_everest_make_public( mbedtls_ecdh_context_everest *ctx, size_t *olen, unsigned char *buf, size_t blen, int( *f_rng )( void *, unsigned char *, size_t ), void *p_rng ); /** * \brief This function parses and processes a TLS ClientKeyExchange * payload. * * This is the third function used by a TLS server for ECDH(E) * ciphersuites. (It is called after mbedtls_ecdh_setup() and * mbedtls_ecdh_make_params().) * * \see ecp.h * * \param ctx The ECDH context. * \param buf The start of the input buffer. * \param blen The length of the input buffer. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. */ int mbedtls_everest_read_public( mbedtls_ecdh_context_everest *ctx, const unsigned char *buf, size_t blen ); /** * \brief This function derives and exports the shared secret. * * This is the last function used by both TLS client * and servers. * * \note If \p f_rng is not NULL, it is used to implement * countermeasures against side-channel attacks. * For more information, see mbedtls_ecp_mul(). * * \see ecp.h * * \param ctx The ECDH context. * \param olen The number of Bytes written. * \param buf The destination buffer. * \param blen The length of the destination buffer. * \param f_rng The RNG function. * \param p_rng The RNG context. * * \return \c 0 on success. * \return An \c MBEDTLS_ERR_ECP_XXX error code on failure. */ int mbedtls_everest_calc_secret( mbedtls_ecdh_context_everest *ctx, size_t *olen, unsigned char *buf, size_t blen, int( *f_rng )( void *, unsigned char *, size_t ), void *p_rng ); #ifdef __cplusplus } #endif #endif /* MBEDTLS_EVEREST_H */