187 lines
5.8 KiB
C
187 lines
5.8 KiB
C
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/*
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* ECDH with curve-optimized implementation multiplexing
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*
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* Copyright 2016-2018 INRIA and Microsoft Corporation
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#include "common.h"
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#if defined(MBEDTLS_ECDH_C) && defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED)
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#include <mbedtls/ecdh.h>
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#if !(defined(__SIZEOF_INT128__) && (__SIZEOF_INT128__ == 16))
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#define KRML_VERIFIED_UINT128
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#endif
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#include <Hacl_Curve25519.h>
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#include <mbedtls/platform_util.h>
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#include "x25519.h"
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#include <string.h>
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/*
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* Initialize context
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*/
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void mbedtls_x25519_init( mbedtls_x25519_context *ctx )
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{
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mbedtls_platform_zeroize( ctx, sizeof( mbedtls_x25519_context ) );
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}
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/*
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* Free context
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*/
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void mbedtls_x25519_free( mbedtls_x25519_context *ctx )
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{
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if( ctx == NULL )
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return;
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mbedtls_platform_zeroize( ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
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mbedtls_platform_zeroize( ctx->peer_point, MBEDTLS_X25519_KEY_SIZE_BYTES );
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}
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int mbedtls_x25519_make_params( mbedtls_x25519_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int( *f_rng )(void *, unsigned char *, size_t),
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void *p_rng )
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{
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int ret = 0;
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uint8_t base[MBEDTLS_X25519_KEY_SIZE_BYTES] = {0};
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if( ( ret = f_rng( p_rng, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES ) ) != 0 )
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return ret;
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*olen = MBEDTLS_X25519_KEY_SIZE_BYTES + 4;
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if( blen < *olen )
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return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
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*buf++ = MBEDTLS_ECP_TLS_NAMED_CURVE;
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*buf++ = MBEDTLS_ECP_TLS_CURVE25519 >> 8;
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*buf++ = MBEDTLS_ECP_TLS_CURVE25519 & 0xFF;
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*buf++ = MBEDTLS_X25519_KEY_SIZE_BYTES;
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base[0] = 9;
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Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, base );
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base[0] = 0;
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if( memcmp( buf, base, MBEDTLS_X25519_KEY_SIZE_BYTES) == 0 )
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return MBEDTLS_ERR_ECP_RANDOM_FAILED;
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return( 0 );
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}
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int mbedtls_x25519_read_params( mbedtls_x25519_context *ctx,
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const unsigned char **buf, const unsigned char *end )
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{
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if( end - *buf < MBEDTLS_X25519_KEY_SIZE_BYTES + 1 )
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return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
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if( ( *(*buf)++ != MBEDTLS_X25519_KEY_SIZE_BYTES ) )
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return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
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memcpy( ctx->peer_point, *buf, MBEDTLS_X25519_KEY_SIZE_BYTES );
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*buf += MBEDTLS_X25519_KEY_SIZE_BYTES;
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return( 0 );
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}
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int mbedtls_x25519_get_params( mbedtls_x25519_context *ctx, const mbedtls_ecp_keypair *key,
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mbedtls_x25519_ecdh_side side )
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{
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size_t olen = 0;
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switch( side ) {
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case MBEDTLS_X25519_ECDH_THEIRS:
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return mbedtls_ecp_point_write_binary( &key->grp, &key->Q, MBEDTLS_ECP_PF_COMPRESSED, &olen, ctx->peer_point, MBEDTLS_X25519_KEY_SIZE_BYTES );
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case MBEDTLS_X25519_ECDH_OURS:
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return mbedtls_mpi_write_binary_le( &key->d, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
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default:
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return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
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}
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}
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int mbedtls_x25519_calc_secret( mbedtls_x25519_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int( *f_rng )(void *, unsigned char *, size_t),
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void *p_rng )
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{
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/* f_rng and p_rng are not used here because this implementation does not
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need blinding since it has constant trace. */
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(( void )f_rng);
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(( void )p_rng);
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*olen = MBEDTLS_X25519_KEY_SIZE_BYTES;
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if( blen < *olen )
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return( MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL );
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Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, ctx->peer_point);
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/* Wipe the DH secret and don't let the peer chose a small subgroup point */
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mbedtls_platform_zeroize( ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES );
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if( memcmp( buf, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES) == 0 )
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return MBEDTLS_ERR_ECP_RANDOM_FAILED;
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return( 0 );
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}
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int mbedtls_x25519_make_public( mbedtls_x25519_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int( *f_rng )(void *, unsigned char *, size_t),
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void *p_rng )
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{
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int ret = 0;
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unsigned char base[MBEDTLS_X25519_KEY_SIZE_BYTES] = { 0 };
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if( ctx == NULL )
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return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
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if( ( ret = f_rng( p_rng, ctx->our_secret, MBEDTLS_X25519_KEY_SIZE_BYTES ) ) != 0 )
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return ret;
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*olen = MBEDTLS_X25519_KEY_SIZE_BYTES + 1;
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if( blen < *olen )
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return(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL);
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*buf++ = MBEDTLS_X25519_KEY_SIZE_BYTES;
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base[0] = 9;
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Hacl_Curve25519_crypto_scalarmult( buf, ctx->our_secret, base );
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base[0] = 0;
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if( memcmp( buf, base, MBEDTLS_X25519_KEY_SIZE_BYTES ) == 0 )
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return MBEDTLS_ERR_ECP_RANDOM_FAILED;
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return( ret );
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}
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int mbedtls_x25519_read_public( mbedtls_x25519_context *ctx,
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const unsigned char *buf, size_t blen )
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{
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if( blen < MBEDTLS_X25519_KEY_SIZE_BYTES + 1 )
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return(MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL);
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if( (*buf++ != MBEDTLS_X25519_KEY_SIZE_BYTES) )
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return(MBEDTLS_ERR_ECP_BAD_INPUT_DATA);
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memcpy( ctx->peer_point, buf, MBEDTLS_X25519_KEY_SIZE_BYTES );
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return( 0 );
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}
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#endif /* MBEDTLS_ECDH_C && MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED */
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