forked from LeenkxTeam/LNXSDK
269 lines
7.4 KiB
C
269 lines
7.4 KiB
C
/*
|
|
* Elliptic curve Diffie-Hellman
|
|
*
|
|
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
|
|
* 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)
|
|
*/
|
|
|
|
/*
|
|
* References:
|
|
*
|
|
* SEC1 http://www.secg.org/index.php?action=secg,docs_secg
|
|
* RFC 4492
|
|
*/
|
|
|
|
#if !defined(MBEDTLS_CONFIG_FILE)
|
|
#include "mbedtls/config.h"
|
|
#else
|
|
#include MBEDTLS_CONFIG_FILE
|
|
#endif
|
|
|
|
#if defined(MBEDTLS_ECDH_C)
|
|
|
|
#include "mbedtls/ecdh.h"
|
|
|
|
#include <string.h>
|
|
|
|
#if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
|
|
/*
|
|
* Generate public key: simple wrapper around mbedtls_ecp_gen_keypair
|
|
*/
|
|
int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
|
|
int (*f_rng)(void *, unsigned char *, size_t),
|
|
void *p_rng )
|
|
{
|
|
return mbedtls_ecp_gen_keypair( grp, d, Q, f_rng, p_rng );
|
|
}
|
|
#endif /* MBEDTLS_ECDH_GEN_PUBLIC_ALT */
|
|
|
|
#if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT)
|
|
/*
|
|
* Compute shared secret (SEC1 3.3.1)
|
|
*/
|
|
int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
|
|
const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
|
|
int (*f_rng)(void *, unsigned char *, size_t),
|
|
void *p_rng )
|
|
{
|
|
int ret;
|
|
mbedtls_ecp_point P;
|
|
|
|
mbedtls_ecp_point_init( &P );
|
|
|
|
/*
|
|
* Make sure Q is a valid pubkey before using it
|
|
*/
|
|
MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, Q ) );
|
|
|
|
MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, &P, d, Q, f_rng, p_rng ) );
|
|
|
|
if( mbedtls_ecp_is_zero( &P ) )
|
|
{
|
|
ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
|
|
goto cleanup;
|
|
}
|
|
|
|
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( z, &P.X ) );
|
|
|
|
cleanup:
|
|
mbedtls_ecp_point_free( &P );
|
|
|
|
return( ret );
|
|
}
|
|
#endif /* MBEDTLS_ECDH_COMPUTE_SHARED_ALT */
|
|
|
|
/*
|
|
* Initialize context
|
|
*/
|
|
void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx )
|
|
{
|
|
memset( ctx, 0, sizeof( mbedtls_ecdh_context ) );
|
|
}
|
|
|
|
/*
|
|
* Free context
|
|
*/
|
|
void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx )
|
|
{
|
|
if( ctx == NULL )
|
|
return;
|
|
|
|
mbedtls_ecp_group_free( &ctx->grp );
|
|
mbedtls_ecp_point_free( &ctx->Q );
|
|
mbedtls_ecp_point_free( &ctx->Qp );
|
|
mbedtls_ecp_point_free( &ctx->Vi );
|
|
mbedtls_ecp_point_free( &ctx->Vf );
|
|
mbedtls_mpi_free( &ctx->d );
|
|
mbedtls_mpi_free( &ctx->z );
|
|
mbedtls_mpi_free( &ctx->_d );
|
|
}
|
|
|
|
/*
|
|
* Setup and write the ServerKeyExhange parameters (RFC 4492)
|
|
* struct {
|
|
* ECParameters curve_params;
|
|
* ECPoint public;
|
|
* } ServerECDHParams;
|
|
*/
|
|
int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
|
|
unsigned char *buf, size_t blen,
|
|
int (*f_rng)(void *, unsigned char *, size_t),
|
|
void *p_rng )
|
|
{
|
|
int ret;
|
|
size_t grp_len, pt_len;
|
|
|
|
if( ctx == NULL || ctx->grp.pbits == 0 )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) )
|
|
!= 0 )
|
|
return( ret );
|
|
|
|
if( ( ret = mbedtls_ecp_tls_write_group( &ctx->grp, &grp_len, buf, blen ) )
|
|
!= 0 )
|
|
return( ret );
|
|
|
|
buf += grp_len;
|
|
blen -= grp_len;
|
|
|
|
if( ( ret = mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, ctx->point_format,
|
|
&pt_len, buf, blen ) ) != 0 )
|
|
return( ret );
|
|
|
|
*olen = grp_len + pt_len;
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Read the ServerKeyExhange parameters (RFC 4492)
|
|
* struct {
|
|
* ECParameters curve_params;
|
|
* ECPoint public;
|
|
* } ServerECDHParams;
|
|
*/
|
|
int mbedtls_ecdh_read_params( mbedtls_ecdh_context *ctx,
|
|
const unsigned char **buf, const unsigned char *end )
|
|
{
|
|
int ret;
|
|
|
|
if( ( ret = mbedtls_ecp_tls_read_group( &ctx->grp, buf, end - *buf ) ) != 0 )
|
|
return( ret );
|
|
|
|
if( ( ret = mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, buf, end - *buf ) )
|
|
!= 0 )
|
|
return( ret );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Get parameters from a keypair
|
|
*/
|
|
int mbedtls_ecdh_get_params( mbedtls_ecdh_context *ctx, const mbedtls_ecp_keypair *key,
|
|
mbedtls_ecdh_side side )
|
|
{
|
|
int ret;
|
|
|
|
if( ( ret = mbedtls_ecp_group_copy( &ctx->grp, &key->grp ) ) != 0 )
|
|
return( ret );
|
|
|
|
/* If it's not our key, just import the public part as Qp */
|
|
if( side == MBEDTLS_ECDH_THEIRS )
|
|
return( mbedtls_ecp_copy( &ctx->Qp, &key->Q ) );
|
|
|
|
/* Our key: import public (as Q) and private parts */
|
|
if( side != MBEDTLS_ECDH_OURS )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
if( ( ret = mbedtls_ecp_copy( &ctx->Q, &key->Q ) ) != 0 ||
|
|
( ret = mbedtls_mpi_copy( &ctx->d, &key->d ) ) != 0 )
|
|
return( ret );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Setup and export the client public value
|
|
*/
|
|
int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
|
|
unsigned char *buf, size_t blen,
|
|
int (*f_rng)(void *, unsigned char *, size_t),
|
|
void *p_rng )
|
|
{
|
|
int ret;
|
|
|
|
if( ctx == NULL || ctx->grp.pbits == 0 )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) )
|
|
!= 0 )
|
|
return( ret );
|
|
|
|
return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, ctx->point_format,
|
|
olen, buf, blen );
|
|
}
|
|
|
|
/*
|
|
* Parse and import the client's public value
|
|
*/
|
|
int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx,
|
|
const unsigned char *buf, size_t blen )
|
|
{
|
|
int ret;
|
|
const unsigned char *p = buf;
|
|
|
|
if( ctx == NULL )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
if( ( ret = mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, &p, blen ) ) != 0 )
|
|
return( ret );
|
|
|
|
if( (size_t)( p - buf ) != blen )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
return( 0 );
|
|
}
|
|
|
|
/*
|
|
* Derive and export the shared secret
|
|
*/
|
|
int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
|
|
unsigned char *buf, size_t blen,
|
|
int (*f_rng)(void *, unsigned char *, size_t),
|
|
void *p_rng )
|
|
{
|
|
int ret;
|
|
|
|
if( ctx == NULL )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
if( ( ret = mbedtls_ecdh_compute_shared( &ctx->grp, &ctx->z, &ctx->Qp, &ctx->d,
|
|
f_rng, p_rng ) ) != 0 )
|
|
{
|
|
return( ret );
|
|
}
|
|
|
|
if( mbedtls_mpi_size( &ctx->z ) > blen )
|
|
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
|
|
|
*olen = ctx->grp.pbits / 8 + ( ( ctx->grp.pbits % 8 ) != 0 );
|
|
return mbedtls_mpi_write_binary( &ctx->z, buf, *olen );
|
|
}
|
|
|
|
#endif /* MBEDTLS_ECDH_C */
|