Denislam Valeev / Mbed OS Nucleo_rtos_basic

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mbed-os/features/mbedtls/src/ecdh.c@0:e056ac8fecf8, 2018-03-13 (annotated)

Committer:
valeyev
Date:
Tue Mar 13 07:17:50 2018 +0000
Revision:
0:e056ac8fecf8
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Who changed what in which revision?

UserRevisionLine numberNew contents of line
valeyev 0:e056ac8fecf8 1 /*
valeyev 0:e056ac8fecf8 2 * Elliptic curve Diffie-Hellman
valeyev 0:e056ac8fecf8 3 *
valeyev 0:e056ac8fecf8 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
valeyev 0:e056ac8fecf8 5 * SPDX-License-Identifier: Apache-2.0
valeyev 0:e056ac8fecf8 6 *
valeyev 0:e056ac8fecf8 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
valeyev 0:e056ac8fecf8 8 * not use this file except in compliance with the License.
valeyev 0:e056ac8fecf8 9 * You may obtain a copy of the License at
valeyev 0:e056ac8fecf8 10 *
valeyev 0:e056ac8fecf8 11 * http://www.apache.org/licenses/LICENSE-2.0
valeyev 0:e056ac8fecf8 12 *
valeyev 0:e056ac8fecf8 13 * Unless required by applicable law or agreed to in writing, software
valeyev 0:e056ac8fecf8 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
valeyev 0:e056ac8fecf8 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
valeyev 0:e056ac8fecf8 16 * See the License for the specific language governing permissions and
valeyev 0:e056ac8fecf8 17 * limitations under the License.
valeyev 0:e056ac8fecf8 18 *
valeyev 0:e056ac8fecf8 19 * This file is part of mbed TLS (https://tls.mbed.org)
valeyev 0:e056ac8fecf8 20 */
valeyev 0:e056ac8fecf8 21
valeyev 0:e056ac8fecf8 22 /*
valeyev 0:e056ac8fecf8 23 * References:
valeyev 0:e056ac8fecf8 24 *
valeyev 0:e056ac8fecf8 25 * SEC1 http://www.secg.org/index.php?action=secg,docs_secg
valeyev 0:e056ac8fecf8 26 * RFC 4492
valeyev 0:e056ac8fecf8 27 */
valeyev 0:e056ac8fecf8 28
valeyev 0:e056ac8fecf8 29 #if !defined(MBEDTLS_CONFIG_FILE)
valeyev 0:e056ac8fecf8 30 #include "mbedtls/config.h"
valeyev 0:e056ac8fecf8 31 #else
valeyev 0:e056ac8fecf8 32 #include MBEDTLS_CONFIG_FILE
valeyev 0:e056ac8fecf8 33 #endif
valeyev 0:e056ac8fecf8 34
valeyev 0:e056ac8fecf8 35 #if defined(MBEDTLS_ECDH_C)
valeyev 0:e056ac8fecf8 36
valeyev 0:e056ac8fecf8 37 #include "mbedtls/ecdh.h"
valeyev 0:e056ac8fecf8 38
valeyev 0:e056ac8fecf8 39 #include <string.h>
valeyev 0:e056ac8fecf8 40
valeyev 0:e056ac8fecf8 41 #if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT)
valeyev 0:e056ac8fecf8 42 /*
valeyev 0:e056ac8fecf8 43 * Generate public key: simple wrapper around mbedtls_ecp_gen_keypair
valeyev 0:e056ac8fecf8 44 */
valeyev 0:e056ac8fecf8 45 int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q,
valeyev 0:e056ac8fecf8 46 int (*f_rng)(void *, unsigned char *, size_t),
valeyev 0:e056ac8fecf8 47 void *p_rng )
valeyev 0:e056ac8fecf8 48 {
valeyev 0:e056ac8fecf8 49 return mbedtls_ecp_gen_keypair( grp, d, Q, f_rng, p_rng );
valeyev 0:e056ac8fecf8 50 }
valeyev 0:e056ac8fecf8 51 #endif /* MBEDTLS_ECDH_GEN_PUBLIC_ALT */
valeyev 0:e056ac8fecf8 52
valeyev 0:e056ac8fecf8 53 #if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT)
valeyev 0:e056ac8fecf8 54 /*
valeyev 0:e056ac8fecf8 55 * Compute shared secret (SEC1 3.3.1)
valeyev 0:e056ac8fecf8 56 */
valeyev 0:e056ac8fecf8 57 int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z,
valeyev 0:e056ac8fecf8 58 const mbedtls_ecp_point *Q, const mbedtls_mpi *d,
valeyev 0:e056ac8fecf8 59 int (*f_rng)(void *, unsigned char *, size_t),
valeyev 0:e056ac8fecf8 60 void *p_rng )
valeyev 0:e056ac8fecf8 61 {
valeyev 0:e056ac8fecf8 62 int ret;
valeyev 0:e056ac8fecf8 63 mbedtls_ecp_point P;
valeyev 0:e056ac8fecf8 64
valeyev 0:e056ac8fecf8 65 mbedtls_ecp_point_init( &P );
valeyev 0:e056ac8fecf8 66
valeyev 0:e056ac8fecf8 67 /*
valeyev 0:e056ac8fecf8 68 * Make sure Q is a valid pubkey before using it
valeyev 0:e056ac8fecf8 69 */
valeyev 0:e056ac8fecf8 70 MBEDTLS_MPI_CHK( mbedtls_ecp_check_pubkey( grp, Q ) );
valeyev 0:e056ac8fecf8 71
valeyev 0:e056ac8fecf8 72 MBEDTLS_MPI_CHK( mbedtls_ecp_mul( grp, &P, d, Q, f_rng, p_rng ) );
valeyev 0:e056ac8fecf8 73
valeyev 0:e056ac8fecf8 74 if( mbedtls_ecp_is_zero( &P ) )
valeyev 0:e056ac8fecf8 75 {
valeyev 0:e056ac8fecf8 76 ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
valeyev 0:e056ac8fecf8 77 goto cleanup;
valeyev 0:e056ac8fecf8 78 }
valeyev 0:e056ac8fecf8 79
valeyev 0:e056ac8fecf8 80 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( z, &P.X ) );
valeyev 0:e056ac8fecf8 81
valeyev 0:e056ac8fecf8 82 cleanup:
valeyev 0:e056ac8fecf8 83 mbedtls_ecp_point_free( &P );
valeyev 0:e056ac8fecf8 84
valeyev 0:e056ac8fecf8 85 return( ret );
valeyev 0:e056ac8fecf8 86 }
valeyev 0:e056ac8fecf8 87 #endif /* MBEDTLS_ECDH_COMPUTE_SHARED_ALT */
valeyev 0:e056ac8fecf8 88
valeyev 0:e056ac8fecf8 89 /*
valeyev 0:e056ac8fecf8 90 * Initialize context
valeyev 0:e056ac8fecf8 91 */
valeyev 0:e056ac8fecf8 92 void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx )
valeyev 0:e056ac8fecf8 93 {
valeyev 0:e056ac8fecf8 94 memset( ctx, 0, sizeof( mbedtls_ecdh_context ) );
valeyev 0:e056ac8fecf8 95 }
valeyev 0:e056ac8fecf8 96
valeyev 0:e056ac8fecf8 97 /*
valeyev 0:e056ac8fecf8 98 * Free context
valeyev 0:e056ac8fecf8 99 */
valeyev 0:e056ac8fecf8 100 void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx )
valeyev 0:e056ac8fecf8 101 {
valeyev 0:e056ac8fecf8 102 if( ctx == NULL )
valeyev 0:e056ac8fecf8 103 return;
valeyev 0:e056ac8fecf8 104
valeyev 0:e056ac8fecf8 105 mbedtls_ecp_group_free( &ctx->grp );
valeyev 0:e056ac8fecf8 106 mbedtls_ecp_point_free( &ctx->Q );
valeyev 0:e056ac8fecf8 107 mbedtls_ecp_point_free( &ctx->Qp );
valeyev 0:e056ac8fecf8 108 mbedtls_ecp_point_free( &ctx->Vi );
valeyev 0:e056ac8fecf8 109 mbedtls_ecp_point_free( &ctx->Vf );
valeyev 0:e056ac8fecf8 110 mbedtls_mpi_free( &ctx->d );
valeyev 0:e056ac8fecf8 111 mbedtls_mpi_free( &ctx->z );
valeyev 0:e056ac8fecf8 112 mbedtls_mpi_free( &ctx->_d );
valeyev 0:e056ac8fecf8 113 }
valeyev 0:e056ac8fecf8 114
valeyev 0:e056ac8fecf8 115 /*
valeyev 0:e056ac8fecf8 116 * Setup and write the ServerKeyExhange parameters (RFC 4492)
valeyev 0:e056ac8fecf8 117 * struct {
valeyev 0:e056ac8fecf8 118 * ECParameters curve_params;
valeyev 0:e056ac8fecf8 119 * ECPoint public;
valeyev 0:e056ac8fecf8 120 * } ServerECDHParams;
valeyev 0:e056ac8fecf8 121 */
valeyev 0:e056ac8fecf8 122 int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
valeyev 0:e056ac8fecf8 123 unsigned char *buf, size_t blen,
valeyev 0:e056ac8fecf8 124 int (*f_rng)(void *, unsigned char *, size_t),
valeyev 0:e056ac8fecf8 125 void *p_rng )
valeyev 0:e056ac8fecf8 126 {
valeyev 0:e056ac8fecf8 127 int ret;
valeyev 0:e056ac8fecf8 128 size_t grp_len, pt_len;
valeyev 0:e056ac8fecf8 129
valeyev 0:e056ac8fecf8 130 if( ctx == NULL || ctx->grp.pbits == 0 )
valeyev 0:e056ac8fecf8 131 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 132
valeyev 0:e056ac8fecf8 133 if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) )
valeyev 0:e056ac8fecf8 134 != 0 )
valeyev 0:e056ac8fecf8 135 return( ret );
valeyev 0:e056ac8fecf8 136
valeyev 0:e056ac8fecf8 137 if( ( ret = mbedtls_ecp_tls_write_group( &ctx->grp, &grp_len, buf, blen ) )
valeyev 0:e056ac8fecf8 138 != 0 )
valeyev 0:e056ac8fecf8 139 return( ret );
valeyev 0:e056ac8fecf8 140
valeyev 0:e056ac8fecf8 141 buf += grp_len;
valeyev 0:e056ac8fecf8 142 blen -= grp_len;
valeyev 0:e056ac8fecf8 143
valeyev 0:e056ac8fecf8 144 if( ( ret = mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, ctx->point_format,
valeyev 0:e056ac8fecf8 145 &pt_len, buf, blen ) ) != 0 )
valeyev 0:e056ac8fecf8 146 return( ret );
valeyev 0:e056ac8fecf8 147
valeyev 0:e056ac8fecf8 148 *olen = grp_len + pt_len;
valeyev 0:e056ac8fecf8 149 return( 0 );
valeyev 0:e056ac8fecf8 150 }
valeyev 0:e056ac8fecf8 151
valeyev 0:e056ac8fecf8 152 /*
valeyev 0:e056ac8fecf8 153 * Read the ServerKeyExhange parameters (RFC 4492)
valeyev 0:e056ac8fecf8 154 * struct {
valeyev 0:e056ac8fecf8 155 * ECParameters curve_params;
valeyev 0:e056ac8fecf8 156 * ECPoint public;
valeyev 0:e056ac8fecf8 157 * } ServerECDHParams;
valeyev 0:e056ac8fecf8 158 */
valeyev 0:e056ac8fecf8 159 int mbedtls_ecdh_read_params( mbedtls_ecdh_context *ctx,
valeyev 0:e056ac8fecf8 160 const unsigned char **buf, const unsigned char *end )
valeyev 0:e056ac8fecf8 161 {
valeyev 0:e056ac8fecf8 162 int ret;
valeyev 0:e056ac8fecf8 163
valeyev 0:e056ac8fecf8 164 if( ( ret = mbedtls_ecp_tls_read_group( &ctx->grp, buf, end - *buf ) ) != 0 )
valeyev 0:e056ac8fecf8 165 return( ret );
valeyev 0:e056ac8fecf8 166
valeyev 0:e056ac8fecf8 167 if( ( ret = mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, buf, end - *buf ) )
valeyev 0:e056ac8fecf8 168 != 0 )
valeyev 0:e056ac8fecf8 169 return( ret );
valeyev 0:e056ac8fecf8 170
valeyev 0:e056ac8fecf8 171 return( 0 );
valeyev 0:e056ac8fecf8 172 }
valeyev 0:e056ac8fecf8 173
valeyev 0:e056ac8fecf8 174 /*
valeyev 0:e056ac8fecf8 175 * Get parameters from a keypair
valeyev 0:e056ac8fecf8 176 */
valeyev 0:e056ac8fecf8 177 int mbedtls_ecdh_get_params( mbedtls_ecdh_context *ctx, const mbedtls_ecp_keypair *key,
valeyev 0:e056ac8fecf8 178 mbedtls_ecdh_side side )
valeyev 0:e056ac8fecf8 179 {
valeyev 0:e056ac8fecf8 180 int ret;
valeyev 0:e056ac8fecf8 181
valeyev 0:e056ac8fecf8 182 if( ( ret = mbedtls_ecp_group_copy( &ctx->grp, &key->grp ) ) != 0 )
valeyev 0:e056ac8fecf8 183 return( ret );
valeyev 0:e056ac8fecf8 184
valeyev 0:e056ac8fecf8 185 /* If it's not our key, just import the public part as Qp */
valeyev 0:e056ac8fecf8 186 if( side == MBEDTLS_ECDH_THEIRS )
valeyev 0:e056ac8fecf8 187 return( mbedtls_ecp_copy( &ctx->Qp, &key->Q ) );
valeyev 0:e056ac8fecf8 188
valeyev 0:e056ac8fecf8 189 /* Our key: import public (as Q) and private parts */
valeyev 0:e056ac8fecf8 190 if( side != MBEDTLS_ECDH_OURS )
valeyev 0:e056ac8fecf8 191 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 192
valeyev 0:e056ac8fecf8 193 if( ( ret = mbedtls_ecp_copy( &ctx->Q, &key->Q ) ) != 0 ||
valeyev 0:e056ac8fecf8 194 ( ret = mbedtls_mpi_copy( &ctx->d, &key->d ) ) != 0 )
valeyev 0:e056ac8fecf8 195 return( ret );
valeyev 0:e056ac8fecf8 196
valeyev 0:e056ac8fecf8 197 return( 0 );
valeyev 0:e056ac8fecf8 198 }
valeyev 0:e056ac8fecf8 199
valeyev 0:e056ac8fecf8 200 /*
valeyev 0:e056ac8fecf8 201 * Setup and export the client public value
valeyev 0:e056ac8fecf8 202 */
valeyev 0:e056ac8fecf8 203 int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen,
valeyev 0:e056ac8fecf8 204 unsigned char *buf, size_t blen,
valeyev 0:e056ac8fecf8 205 int (*f_rng)(void *, unsigned char *, size_t),
valeyev 0:e056ac8fecf8 206 void *p_rng )
valeyev 0:e056ac8fecf8 207 {
valeyev 0:e056ac8fecf8 208 int ret;
valeyev 0:e056ac8fecf8 209
valeyev 0:e056ac8fecf8 210 if( ctx == NULL || ctx->grp.pbits == 0 )
valeyev 0:e056ac8fecf8 211 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 212
valeyev 0:e056ac8fecf8 213 if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, f_rng, p_rng ) )
valeyev 0:e056ac8fecf8 214 != 0 )
valeyev 0:e056ac8fecf8 215 return( ret );
valeyev 0:e056ac8fecf8 216
valeyev 0:e056ac8fecf8 217 return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, ctx->point_format,
valeyev 0:e056ac8fecf8 218 olen, buf, blen );
valeyev 0:e056ac8fecf8 219 }
valeyev 0:e056ac8fecf8 220
valeyev 0:e056ac8fecf8 221 /*
valeyev 0:e056ac8fecf8 222 * Parse and import the client's public value
valeyev 0:e056ac8fecf8 223 */
valeyev 0:e056ac8fecf8 224 int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx,
valeyev 0:e056ac8fecf8 225 const unsigned char *buf, size_t blen )
valeyev 0:e056ac8fecf8 226 {
valeyev 0:e056ac8fecf8 227 int ret;
valeyev 0:e056ac8fecf8 228 const unsigned char *p = buf;
valeyev 0:e056ac8fecf8 229
valeyev 0:e056ac8fecf8 230 if( ctx == NULL )
valeyev 0:e056ac8fecf8 231 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 232
valeyev 0:e056ac8fecf8 233 if( ( ret = mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, &p, blen ) ) != 0 )
valeyev 0:e056ac8fecf8 234 return( ret );
valeyev 0:e056ac8fecf8 235
valeyev 0:e056ac8fecf8 236 if( (size_t)( p - buf ) != blen )
valeyev 0:e056ac8fecf8 237 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 238
valeyev 0:e056ac8fecf8 239 return( 0 );
valeyev 0:e056ac8fecf8 240 }
valeyev 0:e056ac8fecf8 241
valeyev 0:e056ac8fecf8 242 /*
valeyev 0:e056ac8fecf8 243 * Derive and export the shared secret
valeyev 0:e056ac8fecf8 244 */
valeyev 0:e056ac8fecf8 245 int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
valeyev 0:e056ac8fecf8 246 unsigned char *buf, size_t blen,
valeyev 0:e056ac8fecf8 247 int (*f_rng)(void *, unsigned char *, size_t),
valeyev 0:e056ac8fecf8 248 void *p_rng )
valeyev 0:e056ac8fecf8 249 {
valeyev 0:e056ac8fecf8 250 int ret;
valeyev 0:e056ac8fecf8 251
valeyev 0:e056ac8fecf8 252 if( ctx == NULL )
valeyev 0:e056ac8fecf8 253 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 254
valeyev 0:e056ac8fecf8 255 if( ( ret = mbedtls_ecdh_compute_shared( &ctx->grp, &ctx->z, &ctx->Qp, &ctx->d,
valeyev 0:e056ac8fecf8 256 f_rng, p_rng ) ) != 0 )
valeyev 0:e056ac8fecf8 257 {
valeyev 0:e056ac8fecf8 258 return( ret );
valeyev 0:e056ac8fecf8 259 }
valeyev 0:e056ac8fecf8 260
valeyev 0:e056ac8fecf8 261 if( mbedtls_mpi_size( &ctx->z ) > blen )
valeyev 0:e056ac8fecf8 262 return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
valeyev 0:e056ac8fecf8 263
valeyev 0:e056ac8fecf8 264 *olen = ctx->grp.pbits / 8 + ( ( ctx->grp.pbits % 8 ) != 0 );
valeyev 0:e056ac8fecf8 265 return mbedtls_mpi_write_binary( &ctx->z, buf, *olen );
valeyev 0:e056ac8fecf8 266 }
valeyev 0:e056ac8fecf8 267
valeyev 0:e056ac8fecf8 268 #endif /* MBEDTLS_ECDH_C */