/* | |
* 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 "mbedtls/platform_util.h" | |
#include <string.h> | |
/* Parameter validation macros based on platform_util.h */ | |
#define ECDH_VALIDATE_RET( cond ) \ | |
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA ) | |
#define ECDH_VALIDATE( cond ) \ | |
MBEDTLS_INTERNAL_VALIDATE( cond ) | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
typedef mbedtls_ecdh_context mbedtls_ecdh_context_mbed; | |
#endif | |
static mbedtls_ecp_group_id mbedtls_ecdh_grp_id( | |
const mbedtls_ecdh_context *ctx ) | |
{ | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ctx->grp.id ); | |
#else | |
return( ctx->grp_id ); | |
#endif | |
} | |
#if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT) | |
/* | |
* Generate public key (restartable version) | |
* | |
* Note: this internal function relies on its caller preserving the value of | |
* the output parameter 'd' across continuation calls. This would not be | |
* acceptable for a public function but is OK here as we control call sites. | |
*/ | |
static int ecdh_gen_public_restartable( mbedtls_ecp_group *grp, | |
mbedtls_mpi *d, mbedtls_ecp_point *Q, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
mbedtls_ecp_restart_ctx *rs_ctx ) | |
{ | |
int ret; | |
/* If multiplication is in progress, we already generated a privkey */ | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( rs_ctx == NULL || rs_ctx->rsm == NULL ) | |
#endif | |
MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, Q, d, &grp->G, | |
f_rng, p_rng, rs_ctx ) ); | |
cleanup: | |
return( ret ); | |
} | |
/* | |
* Generate public key | |
*/ | |
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 ) | |
{ | |
ECDH_VALIDATE_RET( grp != NULL ); | |
ECDH_VALIDATE_RET( d != NULL ); | |
ECDH_VALIDATE_RET( Q != NULL ); | |
ECDH_VALIDATE_RET( f_rng != NULL ); | |
return( ecdh_gen_public_restartable( grp, d, Q, f_rng, p_rng, NULL ) ); | |
} | |
#endif /* !MBEDTLS_ECDH_GEN_PUBLIC_ALT */ | |
#if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT) | |
/* | |
* Compute shared secret (SEC1 3.3.1) | |
*/ | |
static int ecdh_compute_shared_restartable( 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, | |
mbedtls_ecp_restart_ctx *rs_ctx ) | |
{ | |
int ret; | |
mbedtls_ecp_point P; | |
mbedtls_ecp_point_init( &P ); | |
MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, &P, d, Q, | |
f_rng, p_rng, rs_ctx ) ); | |
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 ); | |
} | |
/* | |
* 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 ) | |
{ | |
ECDH_VALIDATE_RET( grp != NULL ); | |
ECDH_VALIDATE_RET( Q != NULL ); | |
ECDH_VALIDATE_RET( d != NULL ); | |
ECDH_VALIDATE_RET( z != NULL ); | |
return( ecdh_compute_shared_restartable( grp, z, Q, d, | |
f_rng, p_rng, NULL ) ); | |
} | |
#endif /* !MBEDTLS_ECDH_COMPUTE_SHARED_ALT */ | |
static void ecdh_init_internal( mbedtls_ecdh_context_mbed *ctx ) | |
{ | |
mbedtls_ecp_group_init( &ctx->grp ); | |
mbedtls_mpi_init( &ctx->d ); | |
mbedtls_ecp_point_init( &ctx->Q ); | |
mbedtls_ecp_point_init( &ctx->Qp ); | |
mbedtls_mpi_init( &ctx->z ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
mbedtls_ecp_restart_init( &ctx->rs ); | |
#endif | |
} | |
/* | |
* Initialize context | |
*/ | |
void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx ) | |
{ | |
ECDH_VALIDATE( ctx != NULL ); | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
ecdh_init_internal( ctx ); | |
mbedtls_ecp_point_init( &ctx->Vi ); | |
mbedtls_ecp_point_init( &ctx->Vf ); | |
mbedtls_mpi_init( &ctx->_d ); | |
#else | |
memset( ctx, 0, sizeof( mbedtls_ecdh_context ) ); | |
ctx->var = MBEDTLS_ECDH_VARIANT_NONE; | |
#endif | |
ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED; | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
ctx->restart_enabled = 0; | |
#endif | |
} | |
static int ecdh_setup_internal( mbedtls_ecdh_context_mbed *ctx, | |
mbedtls_ecp_group_id grp_id ) | |
{ | |
int ret; | |
ret = mbedtls_ecp_group_load( &ctx->grp, grp_id ); | |
if( ret != 0 ) | |
{ | |
return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE ); | |
} | |
return( 0 ); | |
} | |
/* | |
* Setup context | |
*/ | |
int mbedtls_ecdh_setup( mbedtls_ecdh_context *ctx, mbedtls_ecp_group_id grp_id ) | |
{ | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_setup_internal( ctx, grp_id ) ); | |
#else | |
switch( grp_id ) | |
{ | |
default: | |
ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED; | |
ctx->var = MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0; | |
ctx->grp_id = grp_id; | |
ecdh_init_internal( &ctx->ctx.mbed_ecdh ); | |
return( ecdh_setup_internal( &ctx->ctx.mbed_ecdh, grp_id ) ); | |
} | |
#endif | |
} | |
static void ecdh_free_internal( mbedtls_ecdh_context_mbed *ctx ) | |
{ | |
mbedtls_ecp_group_free( &ctx->grp ); | |
mbedtls_mpi_free( &ctx->d ); | |
mbedtls_ecp_point_free( &ctx->Q ); | |
mbedtls_ecp_point_free( &ctx->Qp ); | |
mbedtls_mpi_free( &ctx->z ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
mbedtls_ecp_restart_free( &ctx->rs ); | |
#endif | |
} | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
/* | |
* Enable restartable operations for context | |
*/ | |
void mbedtls_ecdh_enable_restart( mbedtls_ecdh_context *ctx ) | |
{ | |
ECDH_VALIDATE( ctx != NULL ); | |
ctx->restart_enabled = 1; | |
} | |
#endif | |
/* | |
* Free context | |
*/ | |
void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx ) | |
{ | |
if( ctx == NULL ) | |
return; | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
mbedtls_ecp_point_free( &ctx->Vi ); | |
mbedtls_ecp_point_free( &ctx->Vf ); | |
mbedtls_mpi_free( &ctx->_d ); | |
ecdh_free_internal( ctx ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
ecdh_free_internal( &ctx->ctx.mbed_ecdh ); | |
break; | |
default: | |
break; | |
} | |
ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED; | |
ctx->var = MBEDTLS_ECDH_VARIANT_NONE; | |
ctx->grp_id = MBEDTLS_ECP_DP_NONE; | |
#endif | |
} | |
static int ecdh_make_params_internal( mbedtls_ecdh_context_mbed *ctx, | |
size_t *olen, int point_format, | |
unsigned char *buf, size_t blen, | |
int (*f_rng)(void *, | |
unsigned char *, | |
size_t), | |
void *p_rng, | |
int restart_enabled ) | |
{ | |
int ret; | |
size_t grp_len, pt_len; | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
mbedtls_ecp_restart_ctx *rs_ctx = NULL; | |
#endif | |
if( ctx->grp.pbits == 0 ) | |
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( restart_enabled ) | |
rs_ctx = &ctx->rs; | |
#else | |
(void) restart_enabled; | |
#endif | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q, | |
f_rng, p_rng, rs_ctx ) ) != 0 ) | |
return( ret ); | |
#else | |
if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, | |
f_rng, p_rng ) ) != 0 ) | |
return( ret ); | |
#endif /* MBEDTLS_ECP_RESTARTABLE */ | |
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, point_format, | |
&pt_len, buf, blen ) ) != 0 ) | |
return( ret ); | |
*olen = grp_len + pt_len; | |
return( 0 ); | |
} | |
/* | |
* 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 restart_enabled = 0; | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
ECDH_VALIDATE_RET( olen != NULL ); | |
ECDH_VALIDATE_RET( buf != NULL ); | |
ECDH_VALIDATE_RET( f_rng != NULL ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
restart_enabled = ctx->restart_enabled; | |
#else | |
(void) restart_enabled; | |
#endif | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_make_params_internal( ctx, olen, ctx->point_format, buf, blen, | |
f_rng, p_rng, restart_enabled ) ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
return( ecdh_make_params_internal( &ctx->ctx.mbed_ecdh, olen, | |
ctx->point_format, buf, blen, | |
f_rng, p_rng, | |
restart_enabled ) ); | |
default: | |
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; | |
} | |
#endif | |
} | |
static int ecdh_read_params_internal( mbedtls_ecdh_context_mbed *ctx, | |
const unsigned char **buf, | |
const unsigned char *end ) | |
{ | |
return( mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, buf, | |
end - *buf ) ); | |
} | |
/* | |
* 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; | |
mbedtls_ecp_group_id grp_id; | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
ECDH_VALIDATE_RET( buf != NULL ); | |
ECDH_VALIDATE_RET( *buf != NULL ); | |
ECDH_VALIDATE_RET( end != NULL ); | |
if( ( ret = mbedtls_ecp_tls_read_group_id( &grp_id, buf, end - *buf ) ) | |
!= 0 ) | |
return( ret ); | |
if( ( ret = mbedtls_ecdh_setup( ctx, grp_id ) ) != 0 ) | |
return( ret ); | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_read_params_internal( ctx, buf, end ) ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
return( ecdh_read_params_internal( &ctx->ctx.mbed_ecdh, | |
buf, end ) ); | |
default: | |
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; | |
} | |
#endif | |
} | |
static int ecdh_get_params_internal( mbedtls_ecdh_context_mbed *ctx, | |
const mbedtls_ecp_keypair *key, | |
mbedtls_ecdh_side side ) | |
{ | |
int 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 ); | |
} | |
/* | |
* 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; | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
ECDH_VALIDATE_RET( key != NULL ); | |
ECDH_VALIDATE_RET( side == MBEDTLS_ECDH_OURS || | |
side == MBEDTLS_ECDH_THEIRS ); | |
if( mbedtls_ecdh_grp_id( ctx ) == MBEDTLS_ECP_DP_NONE ) | |
{ | |
/* This is the first call to get_params(). Set up the context | |
* for use with the group. */ | |
if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 ) | |
return( ret ); | |
} | |
else | |
{ | |
/* This is not the first call to get_params(). Check that the | |
* current key's group is the same as the context's, which was set | |
* from the first key's group. */ | |
if( mbedtls_ecdh_grp_id( ctx ) != key->grp.id ) | |
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); | |
} | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_get_params_internal( ctx, key, side ) ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
return( ecdh_get_params_internal( &ctx->ctx.mbed_ecdh, | |
key, side ) ); | |
default: | |
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; | |
} | |
#endif | |
} | |
static int ecdh_make_public_internal( mbedtls_ecdh_context_mbed *ctx, | |
size_t *olen, int point_format, | |
unsigned char *buf, size_t blen, | |
int (*f_rng)(void *, | |
unsigned char *, | |
size_t), | |
void *p_rng, | |
int restart_enabled ) | |
{ | |
int ret; | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
mbedtls_ecp_restart_ctx *rs_ctx = NULL; | |
#endif | |
if( ctx->grp.pbits == 0 ) | |
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( restart_enabled ) | |
rs_ctx = &ctx->rs; | |
#else | |
(void) restart_enabled; | |
#endif | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q, | |
f_rng, p_rng, rs_ctx ) ) != 0 ) | |
return( ret ); | |
#else | |
if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, | |
f_rng, p_rng ) ) != 0 ) | |
return( ret ); | |
#endif /* MBEDTLS_ECP_RESTARTABLE */ | |
return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, point_format, olen, | |
buf, blen ); | |
} | |
/* | |
* 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 restart_enabled = 0; | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
ECDH_VALIDATE_RET( olen != NULL ); | |
ECDH_VALIDATE_RET( buf != NULL ); | |
ECDH_VALIDATE_RET( f_rng != NULL ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
restart_enabled = ctx->restart_enabled; | |
#endif | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_make_public_internal( ctx, olen, ctx->point_format, buf, blen, | |
f_rng, p_rng, restart_enabled ) ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
return( ecdh_make_public_internal( &ctx->ctx.mbed_ecdh, olen, | |
ctx->point_format, buf, blen, | |
f_rng, p_rng, | |
restart_enabled ) ); | |
default: | |
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; | |
} | |
#endif | |
} | |
static int ecdh_read_public_internal( mbedtls_ecdh_context_mbed *ctx, | |
const unsigned char *buf, size_t blen ) | |
{ | |
int ret; | |
const unsigned char *p = buf; | |
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 ); | |
} | |
/* | |
* Parse and import the client's public value | |
*/ | |
int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx, | |
const unsigned char *buf, size_t blen ) | |
{ | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
ECDH_VALIDATE_RET( buf != NULL ); | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_read_public_internal( ctx, buf, blen ) ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
return( ecdh_read_public_internal( &ctx->ctx.mbed_ecdh, | |
buf, blen ) ); | |
default: | |
return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; | |
} | |
#endif | |
} | |
static int ecdh_calc_secret_internal( mbedtls_ecdh_context_mbed *ctx, | |
size_t *olen, unsigned char *buf, | |
size_t blen, | |
int (*f_rng)(void *, | |
unsigned char *, | |
size_t), | |
void *p_rng, | |
int restart_enabled ) | |
{ | |
int ret; | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
mbedtls_ecp_restart_ctx *rs_ctx = NULL; | |
#endif | |
if( ctx == NULL || ctx->grp.pbits == 0 ) | |
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( restart_enabled ) | |
rs_ctx = &ctx->rs; | |
#else | |
(void) restart_enabled; | |
#endif | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
if( ( ret = ecdh_compute_shared_restartable( &ctx->grp, &ctx->z, &ctx->Qp, | |
&ctx->d, f_rng, p_rng, | |
rs_ctx ) ) != 0 ) | |
{ | |
return( ret ); | |
} | |
#else | |
if( ( ret = mbedtls_ecdh_compute_shared( &ctx->grp, &ctx->z, &ctx->Qp, | |
&ctx->d, f_rng, p_rng ) ) != 0 ) | |
{ | |
return( ret ); | |
} | |
#endif /* MBEDTLS_ECP_RESTARTABLE */ | |
if( mbedtls_mpi_size( &ctx->z ) > blen ) | |
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); | |
*olen = ctx->grp.pbits / 8 + ( ( ctx->grp.pbits % 8 ) != 0 ); | |
if( mbedtls_ecp_get_type( &ctx->grp ) == MBEDTLS_ECP_TYPE_MONTGOMERY ) | |
return mbedtls_mpi_write_binary_le( &ctx->z, buf, *olen ); | |
return mbedtls_mpi_write_binary( &ctx->z, buf, *olen ); | |
} | |
/* | |
* 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 restart_enabled = 0; | |
ECDH_VALIDATE_RET( ctx != NULL ); | |
ECDH_VALIDATE_RET( olen != NULL ); | |
ECDH_VALIDATE_RET( buf != NULL ); | |
#if defined(MBEDTLS_ECP_RESTARTABLE) | |
restart_enabled = ctx->restart_enabled; | |
#endif | |
#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) | |
return( ecdh_calc_secret_internal( ctx, olen, buf, blen, f_rng, p_rng, | |
restart_enabled ) ); | |
#else | |
switch( ctx->var ) | |
{ | |
case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: | |
return( ecdh_calc_secret_internal( &ctx->ctx.mbed_ecdh, olen, buf, | |
blen, f_rng, p_rng, | |
restart_enabled ) ); | |
default: | |
return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); | |
} | |
#endif | |
} | |
#endif /* MBEDTLS_ECDH_C */ |