[398] | 1 | /*
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| 2 | * Elliptic curve Diffie-Hellman
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| 3 | *
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| 4 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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| 5 | * SPDX-License-Identifier: Apache-2.0
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| 6 | *
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| 7 | * Licensed under the Apache License, Version 2.0 (the "License"); you may
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| 8 | * not use this file except in compliance with the License.
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| 9 | * You may obtain a copy of the License at
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| 10 | *
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| 11 | * http://www.apache.org/licenses/LICENSE-2.0
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| 12 | *
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| 13 | * Unless required by applicable law or agreed to in writing, software
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| 14 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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| 15 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 16 | * See the License for the specific language governing permissions and
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| 17 | * limitations under the License.
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| 18 | *
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| 19 | * This file is part of mbed TLS (https://tls.mbed.org)
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| 20 | */
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| 21 |
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| 22 | /*
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| 23 | * References:
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| 24 | *
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| 25 | * SEC1 http://www.secg.org/index.php?action=secg,docs_secg
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| 26 | * RFC 4492
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| 27 | */
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| 28 |
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| 29 | #if !defined(MBEDTLS_CONFIG_FILE)
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| 30 | #include "mbedtls/config.h"
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| 31 | #else
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| 32 | #include MBEDTLS_CONFIG_FILE
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| 33 | #endif
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| 34 |
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| 35 | #if defined(MBEDTLS_ECDH_C)
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| 36 |
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| 37 | #include "mbedtls/ecdh.h"
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| 38 | #include "mbedtls/platform_util.h"
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| 39 |
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| 40 | #include <string.h>
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| 41 |
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| 42 | /* Parameter validation macros based on platform_util.h */
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| 43 | #define ECDH_VALIDATE_RET( cond ) \
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| 44 | MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA )
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| 45 | #define ECDH_VALIDATE( cond ) \
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| 46 | MBEDTLS_INTERNAL_VALIDATE( cond )
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| 47 |
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| 48 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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| 49 | typedef mbedtls_ecdh_context mbedtls_ecdh_context_mbed;
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| 50 | #endif
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| 51 |
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| 52 | #if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
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| 53 | /*
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| 54 | * Generate public key (restartable version)
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| 55 | *
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| 56 | * Note: this internal function relies on its caller preserving the value of
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| 57 | * the output parameter 'd' across continuation calls. This would not be
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| 58 | * acceptable for a public function but is OK here as we control call sites.
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| 59 | */
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| 60 | static int ecdh_gen_public_restartable( mbedtls_ecp_group *grp,
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| 61 | mbedtls_mpi *d, mbedtls_ecp_point *Q,
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| 62 | int (*f_rng)(void *, unsigned char *, size_t),
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| 63 | void *p_rng,
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| 64 | mbedtls_ecp_restart_ctx *rs_ctx )
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| 65 | {
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| 66 | int ret;
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| 67 |
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| 68 | /* If multiplication is in progress, we already generated a privkey */
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| 69 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 70 | if( rs_ctx == NULL || rs_ctx->rsm == NULL )
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| 71 | #endif
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| 72 | MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) );
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| 73 |
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| 74 | MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, Q, d, &grp->G,
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| 75 | f_rng, p_rng, rs_ctx ) );
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| 76 |
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| 77 | cleanup:
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| 78 | return( ret );
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| 79 | }
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| 80 |
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| 81 | /*
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| 82 | * Generate public key
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| 83 | */
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| 84 | int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
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| 85 | int (*f_rng)(void *, unsigned char *, size_t),
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| 86 | void *p_rng )
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| 87 | {
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| 88 | ECDH_VALIDATE_RET( grp != NULL );
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| 89 | ECDH_VALIDATE_RET( d != NULL );
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| 90 | ECDH_VALIDATE_RET( Q != NULL );
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| 91 | ECDH_VALIDATE_RET( f_rng != NULL );
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| 92 | return( ecdh_gen_public_restartable( grp, d, Q, f_rng, p_rng, NULL ) );
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| 93 | }
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| 94 | #endif /* !MBEDTLS_ECDH_GEN_PUBLIC_ALT */
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| 95 |
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| 96 | #if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT)
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| 97 | /*
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| 98 | * Compute shared secret (SEC1 3.3.1)
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| 99 | */
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| 100 | static int ecdh_compute_shared_restartable( mbedtls_ecp_group *grp,
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| 101 | mbedtls_mpi *z,
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| 102 | const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
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| 103 | int (*f_rng)(void *, unsigned char *, size_t),
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| 104 | void *p_rng,
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| 105 | mbedtls_ecp_restart_ctx *rs_ctx )
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| 106 | {
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| 107 | int ret;
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| 108 | mbedtls_ecp_point P;
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| 109 |
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| 110 | mbedtls_ecp_point_init( &P );
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| 111 |
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| 112 | MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, &P, d, Q,
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| 113 | f_rng, p_rng, rs_ctx ) );
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| 114 |
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| 115 | if( mbedtls_ecp_is_zero( &P ) )
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| 116 | {
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| 117 | ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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| 118 | goto cleanup;
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| 119 | }
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| 120 |
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| 121 | MBEDTLS_MPI_CHK( mbedtls_mpi_copy( z, &P.X ) );
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| 122 |
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| 123 | cleanup:
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| 124 | mbedtls_ecp_point_free( &P );
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| 125 |
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| 126 | return( ret );
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| 127 | }
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| 128 |
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| 129 | /*
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| 130 | * Compute shared secret (SEC1 3.3.1)
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| 131 | */
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| 132 | int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
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| 133 | const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
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| 134 | int (*f_rng)(void *, unsigned char *, size_t),
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| 135 | void *p_rng )
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| 136 | {
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| 137 | ECDH_VALIDATE_RET( grp != NULL );
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| 138 | ECDH_VALIDATE_RET( Q != NULL );
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| 139 | ECDH_VALIDATE_RET( d != NULL );
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| 140 | ECDH_VALIDATE_RET( z != NULL );
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| 141 | return( ecdh_compute_shared_restartable( grp, z, Q, d,
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| 142 | f_rng, p_rng, NULL ) );
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| 143 | }
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| 144 | #endif /* !MBEDTLS_ECDH_COMPUTE_SHARED_ALT */
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| 145 |
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| 146 | static void ecdh_init_internal( mbedtls_ecdh_context_mbed *ctx )
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| 147 | {
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| 148 | mbedtls_ecp_group_init( &ctx->grp );
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| 149 | mbedtls_mpi_init( &ctx->d );
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| 150 | mbedtls_ecp_point_init( &ctx->Q );
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| 151 | mbedtls_ecp_point_init( &ctx->Qp );
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| 152 | mbedtls_mpi_init( &ctx->z );
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| 153 |
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| 154 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 155 | mbedtls_ecp_restart_init( &ctx->rs );
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| 156 | #endif
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| 157 | }
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| 158 |
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| 159 | /*
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| 160 | * Initialize context
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| 161 | */
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| 162 | void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx )
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| 163 | {
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| 164 | ECDH_VALIDATE( ctx != NULL );
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| 165 |
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| 166 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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| 167 | ecdh_init_internal( ctx );
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| 168 | mbedtls_ecp_point_init( &ctx->Vi );
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| 169 | mbedtls_ecp_point_init( &ctx->Vf );
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| 170 | mbedtls_mpi_init( &ctx->_d );
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| 171 | #else
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| 172 | memset( ctx, 0, sizeof( mbedtls_ecdh_context ) );
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| 173 |
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| 174 | ctx->var = MBEDTLS_ECDH_VARIANT_NONE;
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| 175 | #endif
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| 176 | ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED;
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| 177 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 178 | ctx->restart_enabled = 0;
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| 179 | #endif
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| 180 | }
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| 181 |
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| 182 | static int ecdh_setup_internal( mbedtls_ecdh_context_mbed *ctx,
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| 183 | mbedtls_ecp_group_id grp_id )
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| 184 | {
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| 185 | int ret;
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| 186 |
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| 187 | ret = mbedtls_ecp_group_load( &ctx->grp, grp_id );
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| 188 | if( ret != 0 )
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| 189 | {
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| 190 | return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE );
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| 191 | }
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| 192 |
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| 193 | return( 0 );
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| 194 | }
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| 195 |
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| 196 | /*
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| 197 | * Setup context
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| 198 | */
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| 199 | int mbedtls_ecdh_setup( mbedtls_ecdh_context *ctx, mbedtls_ecp_group_id grp_id )
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| 200 | {
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| 201 | ECDH_VALIDATE_RET( ctx != NULL );
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| 202 |
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| 203 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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| 204 | return( ecdh_setup_internal( ctx, grp_id ) );
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| 205 | #else
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| 206 | switch( grp_id )
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| 207 | {
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| 208 | default:
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| 209 | ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED;
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| 210 | ctx->var = MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0;
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| 211 | ctx->grp_id = grp_id;
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| 212 | ecdh_init_internal( &ctx->ctx.mbed_ecdh );
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| 213 | return( ecdh_setup_internal( &ctx->ctx.mbed_ecdh, grp_id ) );
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| 214 | }
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| 215 | #endif
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| 216 | }
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| 217 |
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| 218 | static void ecdh_free_internal( mbedtls_ecdh_context_mbed *ctx )
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| 219 | {
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| 220 | mbedtls_ecp_group_free( &ctx->grp );
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| 221 | mbedtls_mpi_free( &ctx->d );
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| 222 | mbedtls_ecp_point_free( &ctx->Q );
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| 223 | mbedtls_ecp_point_free( &ctx->Qp );
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| 224 | mbedtls_mpi_free( &ctx->z );
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| 225 |
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| 226 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 227 | mbedtls_ecp_restart_free( &ctx->rs );
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| 228 | #endif
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| 229 | }
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| 230 |
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| 231 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 232 | /*
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| 233 | * Enable restartable operations for context
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| 234 | */
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| 235 | void mbedtls_ecdh_enable_restart( mbedtls_ecdh_context *ctx )
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| 236 | {
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| 237 | ECDH_VALIDATE( ctx != NULL );
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| 238 |
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| 239 | ctx->restart_enabled = 1;
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| 240 | }
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| 241 | #endif
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| 242 |
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| 243 | /*
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| 244 | * Free context
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| 245 | */
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| 246 | void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx )
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| 247 | {
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| 248 | if( ctx == NULL )
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| 249 | return;
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| 250 |
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| 251 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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| 252 | mbedtls_ecp_point_free( &ctx->Vi );
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| 253 | mbedtls_ecp_point_free( &ctx->Vf );
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| 254 | mbedtls_mpi_free( &ctx->_d );
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| 255 | ecdh_free_internal( ctx );
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| 256 | #else
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| 257 | switch( ctx->var )
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| 258 | {
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| 259 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
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| 260 | ecdh_free_internal( &ctx->ctx.mbed_ecdh );
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| 261 | break;
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| 262 | default:
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| 263 | break;
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| 264 | }
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| 265 |
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| 266 | ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED;
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| 267 | ctx->var = MBEDTLS_ECDH_VARIANT_NONE;
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| 268 | ctx->grp_id = MBEDTLS_ECP_DP_NONE;
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| 269 | #endif
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| 270 | }
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| 271 |
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| 272 | static int ecdh_make_params_internal( mbedtls_ecdh_context_mbed *ctx,
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| 273 | size_t *olen, int point_format,
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| 274 | unsigned char *buf, size_t blen,
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| 275 | int (*f_rng)(void *,
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| 276 | unsigned char *,
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| 277 | size_t),
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| 278 | void *p_rng,
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| 279 | int restart_enabled )
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| 280 | {
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| 281 | int ret;
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| 282 | size_t grp_len, pt_len;
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| 283 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 284 | mbedtls_ecp_restart_ctx *rs_ctx = NULL;
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| 285 | #endif
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| 286 |
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| 287 | if( ctx->grp.pbits == 0 )
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| 288 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
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| 289 |
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| 290 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 291 | if( restart_enabled )
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| 292 | rs_ctx = &ctx->rs;
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| 293 | #else
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| 294 | (void) restart_enabled;
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| 295 | #endif
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| 296 |
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| 297 |
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| 298 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 299 | if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
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| 300 | f_rng, p_rng, rs_ctx ) ) != 0 )
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| 301 | return( ret );
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| 302 | #else
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| 303 | if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q,
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| 304 | f_rng, p_rng ) ) != 0 )
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| 305 | return( ret );
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| 306 | #endif /* MBEDTLS_ECP_RESTARTABLE */
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| 307 |
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| 308 | if( ( ret = mbedtls_ecp_tls_write_group( &ctx->grp, &grp_len, buf,
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| 309 | blen ) ) != 0 )
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| 310 | return( ret );
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| 311 |
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| 312 | buf += grp_len;
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| 313 | blen -= grp_len;
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| 314 |
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| 315 | if( ( ret = mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, point_format,
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| 316 | &pt_len, buf, blen ) ) != 0 )
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| 317 | return( ret );
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| 318 |
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| 319 | *olen = grp_len + pt_len;
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| 320 | return( 0 );
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| 321 | }
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| 322 |
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| 323 | /*
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| 324 | * Setup and write the ServerKeyExhange parameters (RFC 4492)
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| 325 | * struct {
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| 326 | * ECParameters curve_params;
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| 327 | * ECPoint public;
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| 328 | * } ServerECDHParams;
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| 329 | */
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| 330 | int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
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| 331 | unsigned char *buf, size_t blen,
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| 332 | int (*f_rng)(void *, unsigned char *, size_t),
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| 333 | void *p_rng )
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| 334 | {
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| 335 | int restart_enabled = 0;
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| 336 | ECDH_VALIDATE_RET( ctx != NULL );
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| 337 | ECDH_VALIDATE_RET( olen != NULL );
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| 338 | ECDH_VALIDATE_RET( buf != NULL );
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| 339 | ECDH_VALIDATE_RET( f_rng != NULL );
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| 340 |
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| 341 | #if defined(MBEDTLS_ECP_RESTARTABLE)
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| 342 | restart_enabled = ctx->restart_enabled;
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| 343 | #else
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| 344 | (void) restart_enabled;
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| 345 | #endif
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| 346 |
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| 347 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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| 348 | return( ecdh_make_params_internal( ctx, olen, ctx->point_format, buf, blen,
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| 349 | f_rng, p_rng, restart_enabled ) );
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| 350 | #else
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| 351 | switch( ctx->var )
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| 352 | {
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| 353 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
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| 354 | return( ecdh_make_params_internal( &ctx->ctx.mbed_ecdh, olen,
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| 355 | ctx->point_format, buf, blen,
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| 356 | f_rng, p_rng,
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| 357 | restart_enabled ) );
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| 358 | default:
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| 359 | return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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| 360 | }
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| 361 | #endif
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| 362 | }
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| 363 |
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| 364 | static int ecdh_read_params_internal( mbedtls_ecdh_context_mbed *ctx,
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| 365 | const unsigned char **buf,
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| 366 | const unsigned char *end )
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| 367 | {
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| 368 | return( mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, buf,
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| 369 | end - *buf ) );
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| 370 | }
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| 371 |
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| 372 | /*
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| 373 | * Read the ServerKeyExhange parameters (RFC 4492)
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| 374 | * struct {
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| 375 | * ECParameters curve_params;
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| 376 | * ECPoint public;
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| 377 | * } ServerECDHParams;
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| 378 | */
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| 379 | int mbedtls_ecdh_read_params( mbedtls_ecdh_context *ctx,
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| 380 | const unsigned char **buf,
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| 381 | const unsigned char *end )
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| 382 | {
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| 383 | int ret;
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| 384 | mbedtls_ecp_group_id grp_id;
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| 385 | ECDH_VALIDATE_RET( ctx != NULL );
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| 386 | ECDH_VALIDATE_RET( buf != NULL );
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| 387 | ECDH_VALIDATE_RET( *buf != NULL );
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| 388 | ECDH_VALIDATE_RET( end != NULL );
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| 389 |
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| 390 | if( ( ret = mbedtls_ecp_tls_read_group_id( &grp_id, buf, end - *buf ) )
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| 391 | != 0 )
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| 392 | return( ret );
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| 393 |
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| 394 | if( ( ret = mbedtls_ecdh_setup( ctx, grp_id ) ) != 0 )
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| 395 | return( ret );
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| 396 |
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| 397 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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| 398 | return( ecdh_read_params_internal( ctx, buf, end ) );
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| 399 | #else
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| 400 | switch( ctx->var )
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| 401 | {
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| 402 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
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| 403 | return( ecdh_read_params_internal( &ctx->ctx.mbed_ecdh,
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| 404 | buf, end ) );
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| 405 | default:
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| 406 | return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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| 407 | }
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| 408 | #endif
|
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| 409 | }
|
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| 410 |
|
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| 411 | static int ecdh_get_params_internal( mbedtls_ecdh_context_mbed *ctx,
|
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| 412 | const mbedtls_ecp_keypair *key,
|
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| 413 | mbedtls_ecdh_side side )
|
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| 414 | {
|
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| 415 | int ret;
|
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| 416 |
|
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| 417 | /* If it's not our key, just import the public part as Qp */
|
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| 418 | if( side == MBEDTLS_ECDH_THEIRS )
|
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| 419 | return( mbedtls_ecp_copy( &ctx->Qp, &key->Q ) );
|
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| 420 |
|
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| 421 | /* Our key: import public (as Q) and private parts */
|
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| 422 | if( side != MBEDTLS_ECDH_OURS )
|
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| 423 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
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| 424 |
|
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| 425 | if( ( ret = mbedtls_ecp_copy( &ctx->Q, &key->Q ) ) != 0 ||
|
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| 426 | ( ret = mbedtls_mpi_copy( &ctx->d, &key->d ) ) != 0 )
|
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| 427 | return( ret );
|
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| 428 |
|
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| 429 | return( 0 );
|
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| 430 | }
|
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| 431 |
|
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| 432 | /*
|
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| 433 | * Get parameters from a keypair
|
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| 434 | */
|
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| 435 | int mbedtls_ecdh_get_params( mbedtls_ecdh_context *ctx,
|
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| 436 | const mbedtls_ecp_keypair *key,
|
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| 437 | mbedtls_ecdh_side side )
|
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| 438 | {
|
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| 439 | int ret;
|
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| 440 | ECDH_VALIDATE_RET( ctx != NULL );
|
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| 441 | ECDH_VALIDATE_RET( key != NULL );
|
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| 442 | ECDH_VALIDATE_RET( side == MBEDTLS_ECDH_OURS ||
|
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| 443 | side == MBEDTLS_ECDH_THEIRS );
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| 444 |
|
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| 445 | if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 )
|
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| 446 | return( ret );
|
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| 447 |
|
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| 448 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
|
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| 449 | return( ecdh_get_params_internal( ctx, key, side ) );
|
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| 450 | #else
|
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| 451 | switch( ctx->var )
|
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| 452 | {
|
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| 453 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
|
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| 454 | return( ecdh_get_params_internal( &ctx->ctx.mbed_ecdh,
|
---|
| 455 | key, side ) );
|
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| 456 | default:
|
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| 457 | return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
|
---|
| 458 | }
|
---|
| 459 | #endif
|
---|
| 460 | }
|
---|
| 461 |
|
---|
| 462 | static int ecdh_make_public_internal( mbedtls_ecdh_context_mbed *ctx,
|
---|
| 463 | size_t *olen, int point_format,
|
---|
| 464 | unsigned char *buf, size_t blen,
|
---|
| 465 | int (*f_rng)(void *,
|
---|
| 466 | unsigned char *,
|
---|
| 467 | size_t),
|
---|
| 468 | void *p_rng,
|
---|
| 469 | int restart_enabled )
|
---|
| 470 | {
|
---|
| 471 | int ret;
|
---|
| 472 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 473 | mbedtls_ecp_restart_ctx *rs_ctx = NULL;
|
---|
| 474 | #endif
|
---|
| 475 |
|
---|
| 476 | if( ctx->grp.pbits == 0 )
|
---|
| 477 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
---|
| 478 |
|
---|
| 479 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 480 | if( restart_enabled )
|
---|
| 481 | rs_ctx = &ctx->rs;
|
---|
| 482 | #else
|
---|
| 483 | (void) restart_enabled;
|
---|
| 484 | #endif
|
---|
| 485 |
|
---|
| 486 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 487 | if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
|
---|
| 488 | f_rng, p_rng, rs_ctx ) ) != 0 )
|
---|
| 489 | return( ret );
|
---|
| 490 | #else
|
---|
| 491 | if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q,
|
---|
| 492 | f_rng, p_rng ) ) != 0 )
|
---|
| 493 | return( ret );
|
---|
| 494 | #endif /* MBEDTLS_ECP_RESTARTABLE */
|
---|
| 495 |
|
---|
| 496 | return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, point_format, olen,
|
---|
| 497 | buf, blen );
|
---|
| 498 | }
|
---|
| 499 |
|
---|
| 500 | /*
|
---|
| 501 | * Setup and export the client public value
|
---|
| 502 | */
|
---|
| 503 | int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
|
---|
| 504 | unsigned char *buf, size_t blen,
|
---|
| 505 | int (*f_rng)(void *, unsigned char *, size_t),
|
---|
| 506 | void *p_rng )
|
---|
| 507 | {
|
---|
| 508 | int restart_enabled = 0;
|
---|
| 509 | ECDH_VALIDATE_RET( ctx != NULL );
|
---|
| 510 | ECDH_VALIDATE_RET( olen != NULL );
|
---|
| 511 | ECDH_VALIDATE_RET( buf != NULL );
|
---|
| 512 | ECDH_VALIDATE_RET( f_rng != NULL );
|
---|
| 513 |
|
---|
| 514 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 515 | restart_enabled = ctx->restart_enabled;
|
---|
| 516 | #endif
|
---|
| 517 |
|
---|
| 518 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
|
---|
| 519 | return( ecdh_make_public_internal( ctx, olen, ctx->point_format, buf, blen,
|
---|
| 520 | f_rng, p_rng, restart_enabled ) );
|
---|
| 521 | #else
|
---|
| 522 | switch( ctx->var )
|
---|
| 523 | {
|
---|
| 524 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
|
---|
| 525 | return( ecdh_make_public_internal( &ctx->ctx.mbed_ecdh, olen,
|
---|
| 526 | ctx->point_format, buf, blen,
|
---|
| 527 | f_rng, p_rng,
|
---|
| 528 | restart_enabled ) );
|
---|
| 529 | default:
|
---|
| 530 | return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
|
---|
| 531 | }
|
---|
| 532 | #endif
|
---|
| 533 | }
|
---|
| 534 |
|
---|
| 535 | static int ecdh_read_public_internal( mbedtls_ecdh_context_mbed *ctx,
|
---|
| 536 | const unsigned char *buf, size_t blen )
|
---|
| 537 | {
|
---|
| 538 | int ret;
|
---|
| 539 | const unsigned char *p = buf;
|
---|
| 540 |
|
---|
| 541 | if( ( ret = mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, &p,
|
---|
| 542 | blen ) ) != 0 )
|
---|
| 543 | return( ret );
|
---|
| 544 |
|
---|
| 545 | if( (size_t)( p - buf ) != blen )
|
---|
| 546 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
---|
| 547 |
|
---|
| 548 | return( 0 );
|
---|
| 549 | }
|
---|
| 550 |
|
---|
| 551 | /*
|
---|
| 552 | * Parse and import the client's public value
|
---|
| 553 | */
|
---|
| 554 | int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx,
|
---|
| 555 | const unsigned char *buf, size_t blen )
|
---|
| 556 | {
|
---|
| 557 | ECDH_VALIDATE_RET( ctx != NULL );
|
---|
| 558 | ECDH_VALIDATE_RET( buf != NULL );
|
---|
| 559 |
|
---|
| 560 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
|
---|
| 561 | return( ecdh_read_public_internal( ctx, buf, blen ) );
|
---|
| 562 | #else
|
---|
| 563 | switch( ctx->var )
|
---|
| 564 | {
|
---|
| 565 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
|
---|
| 566 | return( ecdh_read_public_internal( &ctx->ctx.mbed_ecdh,
|
---|
| 567 | buf, blen ) );
|
---|
| 568 | default:
|
---|
| 569 | return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
|
---|
| 570 | }
|
---|
| 571 | #endif
|
---|
| 572 | }
|
---|
| 573 |
|
---|
| 574 | static int ecdh_calc_secret_internal( mbedtls_ecdh_context_mbed *ctx,
|
---|
| 575 | size_t *olen, unsigned char *buf,
|
---|
| 576 | size_t blen,
|
---|
| 577 | int (*f_rng)(void *,
|
---|
| 578 | unsigned char *,
|
---|
| 579 | size_t),
|
---|
| 580 | void *p_rng,
|
---|
| 581 | int restart_enabled )
|
---|
| 582 | {
|
---|
| 583 | int ret;
|
---|
| 584 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 585 | mbedtls_ecp_restart_ctx *rs_ctx = NULL;
|
---|
| 586 | #endif
|
---|
| 587 |
|
---|
| 588 | if( ctx == NULL || ctx->grp.pbits == 0 )
|
---|
| 589 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
---|
| 590 |
|
---|
| 591 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 592 | if( restart_enabled )
|
---|
| 593 | rs_ctx = &ctx->rs;
|
---|
| 594 | #else
|
---|
| 595 | (void) restart_enabled;
|
---|
| 596 | #endif
|
---|
| 597 |
|
---|
| 598 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 599 | if( ( ret = ecdh_compute_shared_restartable( &ctx->grp, &ctx->z, &ctx->Qp,
|
---|
| 600 | &ctx->d, f_rng, p_rng,
|
---|
| 601 | rs_ctx ) ) != 0 )
|
---|
| 602 | {
|
---|
| 603 | return( ret );
|
---|
| 604 | }
|
---|
| 605 | #else
|
---|
| 606 | if( ( ret = mbedtls_ecdh_compute_shared( &ctx->grp, &ctx->z, &ctx->Qp,
|
---|
| 607 | &ctx->d, f_rng, p_rng ) ) != 0 )
|
---|
| 608 | {
|
---|
| 609 | return( ret );
|
---|
| 610 | }
|
---|
| 611 | #endif /* MBEDTLS_ECP_RESTARTABLE */
|
---|
| 612 |
|
---|
| 613 | if( mbedtls_mpi_size( &ctx->z ) > blen )
|
---|
| 614 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
---|
| 615 |
|
---|
| 616 | *olen = ctx->grp.pbits / 8 + ( ( ctx->grp.pbits % 8 ) != 0 );
|
---|
| 617 | return mbedtls_mpi_write_binary( &ctx->z, buf, *olen );
|
---|
| 618 | }
|
---|
| 619 |
|
---|
| 620 | /*
|
---|
| 621 | * Derive and export the shared secret
|
---|
| 622 | */
|
---|
| 623 | int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
|
---|
| 624 | unsigned char *buf, size_t blen,
|
---|
| 625 | int (*f_rng)(void *, unsigned char *, size_t),
|
---|
| 626 | void *p_rng )
|
---|
| 627 | {
|
---|
| 628 | int restart_enabled = 0;
|
---|
| 629 | ECDH_VALIDATE_RET( ctx != NULL );
|
---|
| 630 | ECDH_VALIDATE_RET( olen != NULL );
|
---|
| 631 | ECDH_VALIDATE_RET( buf != NULL );
|
---|
| 632 |
|
---|
| 633 | #if defined(MBEDTLS_ECP_RESTARTABLE)
|
---|
| 634 | restart_enabled = ctx->restart_enabled;
|
---|
| 635 | #endif
|
---|
| 636 |
|
---|
| 637 | #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
|
---|
| 638 | return( ecdh_calc_secret_internal( ctx, olen, buf, blen, f_rng, p_rng,
|
---|
| 639 | restart_enabled ) );
|
---|
| 640 | #else
|
---|
| 641 | switch( ctx->var )
|
---|
| 642 | {
|
---|
| 643 | case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
|
---|
| 644 | return( ecdh_calc_secret_internal( &ctx->ctx.mbed_ecdh, olen, buf,
|
---|
| 645 | blen, f_rng, p_rng,
|
---|
| 646 | restart_enabled ) );
|
---|
| 647 | default:
|
---|
| 648 | return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
|
---|
| 649 | }
|
---|
| 650 | #endif
|
---|
| 651 | }
|
---|
| 652 |
|
---|
| 653 | #endif /* MBEDTLS_ECDH_C */
|
---|