Avnet / WNCInterface

The WDCInterface is is a drop-in replacement for an EthernetInterface class that allows the user to connect to the Internet with a Wistron NeWeb Corporation (WNC) M14A2A Series data module using the standard network Socket API's. This interface class is used in the AT&T Cellular IoT Starter Kit which is sold by Avnet (http://cloudconnectkits.org/product/att-cellular-iot-starter-kit).

Dependencies:   WncControllerK64F

Dependents:   WNCProximityMqtt Pubnub_ATT_IoT_SK_WNC_sync BluemixDemo BluemixQS ... more

See the WNCInterface README in the Wiki tab for detailed information on this library.

mbedtls/source/dhm.c@12:0071cb144c7a, 2016-11-01 (annotated)

Committer:
JMF
Date:
Tue Nov 01 14:22:56 2016 +0000
Revision:
12:0071cb144c7a
Adding mbedtls files

Who changed what in which revision?

UserRevisionLine numberNew contents of line
JMF 12:0071cb144c7a 1 /*
JMF 12:0071cb144c7a 2 * Diffie-Hellman-Merkle key exchange
JMF 12:0071cb144c7a 3 *
JMF 12:0071cb144c7a 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
JMF 12:0071cb144c7a 5 * SPDX-License-Identifier: Apache-2.0
JMF 12:0071cb144c7a 6 *
JMF 12:0071cb144c7a 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
JMF 12:0071cb144c7a 8 * not use this file except in compliance with the License.
JMF 12:0071cb144c7a 9 * You may obtain a copy of the License at
JMF 12:0071cb144c7a 10 *
JMF 12:0071cb144c7a 11 * http://www.apache.org/licenses/LICENSE-2.0
JMF 12:0071cb144c7a 12 *
JMF 12:0071cb144c7a 13 * Unless required by applicable law or agreed to in writing, software
JMF 12:0071cb144c7a 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
JMF 12:0071cb144c7a 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
JMF 12:0071cb144c7a 16 * See the License for the specific language governing permissions and
JMF 12:0071cb144c7a 17 * limitations under the License.
JMF 12:0071cb144c7a 18 *
JMF 12:0071cb144c7a 19 * This file is part of mbed TLS (https://tls.mbed.org)
JMF 12:0071cb144c7a 20 */
JMF 12:0071cb144c7a 21 /*
JMF 12:0071cb144c7a 22 * The following sources were referenced in the design of this implementation
JMF 12:0071cb144c7a 23 * of the Diffie-Hellman-Merkle algorithm:
JMF 12:0071cb144c7a 24 *
JMF 12:0071cb144c7a 25 * [1] Handbook of Applied Cryptography - 1997, Chapter 12
JMF 12:0071cb144c7a 26 * Menezes, van Oorschot and Vanstone
JMF 12:0071cb144c7a 27 *
JMF 12:0071cb144c7a 28 */
JMF 12:0071cb144c7a 29
JMF 12:0071cb144c7a 30 #if !defined(MBEDTLS_CONFIG_FILE)
JMF 12:0071cb144c7a 31 #include "mbedtls/config.h"
JMF 12:0071cb144c7a 32 #else
JMF 12:0071cb144c7a 33 #include MBEDTLS_CONFIG_FILE
JMF 12:0071cb144c7a 34 #endif
JMF 12:0071cb144c7a 35
JMF 12:0071cb144c7a 36 #if defined(MBEDTLS_DHM_C)
JMF 12:0071cb144c7a 37
JMF 12:0071cb144c7a 38 #include "mbedtls/dhm.h"
JMF 12:0071cb144c7a 39
JMF 12:0071cb144c7a 40 #include <string.h>
JMF 12:0071cb144c7a 41
JMF 12:0071cb144c7a 42 #if defined(MBEDTLS_PEM_PARSE_C)
JMF 12:0071cb144c7a 43 #include "mbedtls/pem.h"
JMF 12:0071cb144c7a 44 #endif
JMF 12:0071cb144c7a 45
JMF 12:0071cb144c7a 46 #if defined(MBEDTLS_ASN1_PARSE_C)
JMF 12:0071cb144c7a 47 #include "mbedtls/asn1.h"
JMF 12:0071cb144c7a 48 #endif
JMF 12:0071cb144c7a 49
JMF 12:0071cb144c7a 50 #if defined(MBEDTLS_PLATFORM_C)
JMF 12:0071cb144c7a 51 #include "mbedtls/platform.h"
JMF 12:0071cb144c7a 52 #else
JMF 12:0071cb144c7a 53 #include <stdlib.h>
JMF 12:0071cb144c7a 54 #include <stdio.h>
JMF 12:0071cb144c7a 55 #define mbedtls_printf pc.printf
JMF 12:0071cb144c7a 56 #define mbedtls_calloc calloc
JMF 12:0071cb144c7a 57 #define mbedtls_free free
JMF 12:0071cb144c7a 58 #endif
JMF 12:0071cb144c7a 59
JMF 12:0071cb144c7a 60 /* Implementation that should never be optimized out by the compiler */
JMF 12:0071cb144c7a 61 static void mbedtls_zeroize( void *v, size_t n ) {
JMF 12:0071cb144c7a 62 volatile unsigned char *p = v; while( n-- ) *p++ = 0;
JMF 12:0071cb144c7a 63 }
JMF 12:0071cb144c7a 64
JMF 12:0071cb144c7a 65 /*
JMF 12:0071cb144c7a 66 * helper to validate the mbedtls_mpi size and import it
JMF 12:0071cb144c7a 67 */
JMF 12:0071cb144c7a 68 static int dhm_read_bignum( mbedtls_mpi *X,
JMF 12:0071cb144c7a 69 unsigned char **p,
JMF 12:0071cb144c7a 70 const unsigned char *end )
JMF 12:0071cb144c7a 71 {
JMF 12:0071cb144c7a 72 int ret, n;
JMF 12:0071cb144c7a 73
JMF 12:0071cb144c7a 74 if( end - *p < 2 )
JMF 12:0071cb144c7a 75 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 76
JMF 12:0071cb144c7a 77 n = ( (*p)[0] << 8 ) | (*p)[1];
JMF 12:0071cb144c7a 78 (*p) += 2;
JMF 12:0071cb144c7a 79
JMF 12:0071cb144c7a 80 if( (int)( end - *p ) < n )
JMF 12:0071cb144c7a 81 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 82
JMF 12:0071cb144c7a 83 if( ( ret = mbedtls_mpi_read_binary( X, *p, n ) ) != 0 )
JMF 12:0071cb144c7a 84 return( MBEDTLS_ERR_DHM_READ_PARAMS_FAILED + ret );
JMF 12:0071cb144c7a 85
JMF 12:0071cb144c7a 86 (*p) += n;
JMF 12:0071cb144c7a 87
JMF 12:0071cb144c7a 88 return( 0 );
JMF 12:0071cb144c7a 89 }
JMF 12:0071cb144c7a 90
JMF 12:0071cb144c7a 91 /*
JMF 12:0071cb144c7a 92 * Verify sanity of parameter with regards to P
JMF 12:0071cb144c7a 93 *
JMF 12:0071cb144c7a 94 * Parameter should be: 2 <= public_param <= P - 2
JMF 12:0071cb144c7a 95 *
JMF 12:0071cb144c7a 96 * For more information on the attack, see:
JMF 12:0071cb144c7a 97 * http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf
JMF 12:0071cb144c7a 98 * http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643
JMF 12:0071cb144c7a 99 */
JMF 12:0071cb144c7a 100 static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P )
JMF 12:0071cb144c7a 101 {
JMF 12:0071cb144c7a 102 mbedtls_mpi L, U;
JMF 12:0071cb144c7a 103 int ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
JMF 12:0071cb144c7a 104
JMF 12:0071cb144c7a 105 mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U );
JMF 12:0071cb144c7a 106
JMF 12:0071cb144c7a 107 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) );
JMF 12:0071cb144c7a 108 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) );
JMF 12:0071cb144c7a 109
JMF 12:0071cb144c7a 110 if( mbedtls_mpi_cmp_mpi( param, &L ) >= 0 &&
JMF 12:0071cb144c7a 111 mbedtls_mpi_cmp_mpi( param, &U ) <= 0 )
JMF 12:0071cb144c7a 112 {
JMF 12:0071cb144c7a 113 ret = 0;
JMF 12:0071cb144c7a 114 }
JMF 12:0071cb144c7a 115
JMF 12:0071cb144c7a 116 cleanup:
JMF 12:0071cb144c7a 117 mbedtls_mpi_free( &L ); mbedtls_mpi_free( &U );
JMF 12:0071cb144c7a 118 return( ret );
JMF 12:0071cb144c7a 119 }
JMF 12:0071cb144c7a 120
JMF 12:0071cb144c7a 121 void mbedtls_dhm_init( mbedtls_dhm_context *ctx )
JMF 12:0071cb144c7a 122 {
JMF 12:0071cb144c7a 123 memset( ctx, 0, sizeof( mbedtls_dhm_context ) );
JMF 12:0071cb144c7a 124 }
JMF 12:0071cb144c7a 125
JMF 12:0071cb144c7a 126 /*
JMF 12:0071cb144c7a 127 * Parse the ServerKeyExchange parameters
JMF 12:0071cb144c7a 128 */
JMF 12:0071cb144c7a 129 int mbedtls_dhm_read_params( mbedtls_dhm_context *ctx,
JMF 12:0071cb144c7a 130 unsigned char **p,
JMF 12:0071cb144c7a 131 const unsigned char *end )
JMF 12:0071cb144c7a 132 {
JMF 12:0071cb144c7a 133 int ret;
JMF 12:0071cb144c7a 134
JMF 12:0071cb144c7a 135 if( ( ret = dhm_read_bignum( &ctx->P, p, end ) ) != 0 ||
JMF 12:0071cb144c7a 136 ( ret = dhm_read_bignum( &ctx->G, p, end ) ) != 0 ||
JMF 12:0071cb144c7a 137 ( ret = dhm_read_bignum( &ctx->GY, p, end ) ) != 0 )
JMF 12:0071cb144c7a 138 return( ret );
JMF 12:0071cb144c7a 139
JMF 12:0071cb144c7a 140 if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 )
JMF 12:0071cb144c7a 141 return( ret );
JMF 12:0071cb144c7a 142
JMF 12:0071cb144c7a 143 ctx->len = mbedtls_mpi_size( &ctx->P );
JMF 12:0071cb144c7a 144
JMF 12:0071cb144c7a 145 return( 0 );
JMF 12:0071cb144c7a 146 }
JMF 12:0071cb144c7a 147
JMF 12:0071cb144c7a 148 /*
JMF 12:0071cb144c7a 149 * Setup and write the ServerKeyExchange parameters
JMF 12:0071cb144c7a 150 */
JMF 12:0071cb144c7a 151 int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size,
JMF 12:0071cb144c7a 152 unsigned char *output, size_t *olen,
JMF 12:0071cb144c7a 153 int (*f_rng)(void *, unsigned char *, size_t),
JMF 12:0071cb144c7a 154 void *p_rng )
JMF 12:0071cb144c7a 155 {
JMF 12:0071cb144c7a 156 int ret, count = 0;
JMF 12:0071cb144c7a 157 size_t n1, n2, n3;
JMF 12:0071cb144c7a 158 unsigned char *p;
JMF 12:0071cb144c7a 159
JMF 12:0071cb144c7a 160 if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 )
JMF 12:0071cb144c7a 161 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 162
JMF 12:0071cb144c7a 163 /*
JMF 12:0071cb144c7a 164 * Generate X as large as possible ( < P )
JMF 12:0071cb144c7a 165 */
JMF 12:0071cb144c7a 166 do
JMF 12:0071cb144c7a 167 {
JMF 12:0071cb144c7a 168 mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng );
JMF 12:0071cb144c7a 169
JMF 12:0071cb144c7a 170 while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
JMF 12:0071cb144c7a 171 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
JMF 12:0071cb144c7a 172
JMF 12:0071cb144c7a 173 if( count++ > 10 )
JMF 12:0071cb144c7a 174 return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED );
JMF 12:0071cb144c7a 175 }
JMF 12:0071cb144c7a 176 while( dhm_check_range( &ctx->X, &ctx->P ) != 0 );
JMF 12:0071cb144c7a 177
JMF 12:0071cb144c7a 178 /*
JMF 12:0071cb144c7a 179 * Calculate GX = G^X mod P
JMF 12:0071cb144c7a 180 */
JMF 12:0071cb144c7a 181 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X,
JMF 12:0071cb144c7a 182 &ctx->P , &ctx->RP ) );
JMF 12:0071cb144c7a 183
JMF 12:0071cb144c7a 184 if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 )
JMF 12:0071cb144c7a 185 return( ret );
JMF 12:0071cb144c7a 186
JMF 12:0071cb144c7a 187 /*
JMF 12:0071cb144c7a 188 * export P, G, GX
JMF 12:0071cb144c7a 189 */
JMF 12:0071cb144c7a 190 #define DHM_MPI_EXPORT(X,n) \
JMF 12:0071cb144c7a 191 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, p + 2, n ) ); \
JMF 12:0071cb144c7a 192 *p++ = (unsigned char)( n >> 8 ); \
JMF 12:0071cb144c7a 193 *p++ = (unsigned char)( n ); p += n;
JMF 12:0071cb144c7a 194
JMF 12:0071cb144c7a 195 n1 = mbedtls_mpi_size( &ctx->P );
JMF 12:0071cb144c7a 196 n2 = mbedtls_mpi_size( &ctx->G );
JMF 12:0071cb144c7a 197 n3 = mbedtls_mpi_size( &ctx->GX );
JMF 12:0071cb144c7a 198
JMF 12:0071cb144c7a 199 p = output;
JMF 12:0071cb144c7a 200 DHM_MPI_EXPORT( &ctx->P , n1 );
JMF 12:0071cb144c7a 201 DHM_MPI_EXPORT( &ctx->G , n2 );
JMF 12:0071cb144c7a 202 DHM_MPI_EXPORT( &ctx->GX, n3 );
JMF 12:0071cb144c7a 203
JMF 12:0071cb144c7a 204 *olen = p - output;
JMF 12:0071cb144c7a 205
JMF 12:0071cb144c7a 206 ctx->len = n1;
JMF 12:0071cb144c7a 207
JMF 12:0071cb144c7a 208 cleanup:
JMF 12:0071cb144c7a 209
JMF 12:0071cb144c7a 210 if( ret != 0 )
JMF 12:0071cb144c7a 211 return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED + ret );
JMF 12:0071cb144c7a 212
JMF 12:0071cb144c7a 213 return( 0 );
JMF 12:0071cb144c7a 214 }
JMF 12:0071cb144c7a 215
JMF 12:0071cb144c7a 216 /*
JMF 12:0071cb144c7a 217 * Import the peer's public value G^Y
JMF 12:0071cb144c7a 218 */
JMF 12:0071cb144c7a 219 int mbedtls_dhm_read_public( mbedtls_dhm_context *ctx,
JMF 12:0071cb144c7a 220 const unsigned char *input, size_t ilen )
JMF 12:0071cb144c7a 221 {
JMF 12:0071cb144c7a 222 int ret;
JMF 12:0071cb144c7a 223
JMF 12:0071cb144c7a 224 if( ctx == NULL || ilen < 1 || ilen > ctx->len )
JMF 12:0071cb144c7a 225 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 226
JMF 12:0071cb144c7a 227 if( ( ret = mbedtls_mpi_read_binary( &ctx->GY, input, ilen ) ) != 0 )
JMF 12:0071cb144c7a 228 return( MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED + ret );
JMF 12:0071cb144c7a 229
JMF 12:0071cb144c7a 230 return( 0 );
JMF 12:0071cb144c7a 231 }
JMF 12:0071cb144c7a 232
JMF 12:0071cb144c7a 233 /*
JMF 12:0071cb144c7a 234 * Create own private value X and export G^X
JMF 12:0071cb144c7a 235 */
JMF 12:0071cb144c7a 236 int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size,
JMF 12:0071cb144c7a 237 unsigned char *output, size_t olen,
JMF 12:0071cb144c7a 238 int (*f_rng)(void *, unsigned char *, size_t),
JMF 12:0071cb144c7a 239 void *p_rng )
JMF 12:0071cb144c7a 240 {
JMF 12:0071cb144c7a 241 int ret, count = 0;
JMF 12:0071cb144c7a 242
JMF 12:0071cb144c7a 243 if( ctx == NULL || olen < 1 || olen > ctx->len )
JMF 12:0071cb144c7a 244 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 245
JMF 12:0071cb144c7a 246 if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 )
JMF 12:0071cb144c7a 247 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 248
JMF 12:0071cb144c7a 249 /*
JMF 12:0071cb144c7a 250 * generate X and calculate GX = G^X mod P
JMF 12:0071cb144c7a 251 */
JMF 12:0071cb144c7a 252 do
JMF 12:0071cb144c7a 253 {
JMF 12:0071cb144c7a 254 mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng );
JMF 12:0071cb144c7a 255
JMF 12:0071cb144c7a 256 while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
JMF 12:0071cb144c7a 257 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
JMF 12:0071cb144c7a 258
JMF 12:0071cb144c7a 259 if( count++ > 10 )
JMF 12:0071cb144c7a 260 return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED );
JMF 12:0071cb144c7a 261 }
JMF 12:0071cb144c7a 262 while( dhm_check_range( &ctx->X, &ctx->P ) != 0 );
JMF 12:0071cb144c7a 263
JMF 12:0071cb144c7a 264 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X,
JMF 12:0071cb144c7a 265 &ctx->P , &ctx->RP ) );
JMF 12:0071cb144c7a 266
JMF 12:0071cb144c7a 267 if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 )
JMF 12:0071cb144c7a 268 return( ret );
JMF 12:0071cb144c7a 269
JMF 12:0071cb144c7a 270 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) );
JMF 12:0071cb144c7a 271
JMF 12:0071cb144c7a 272 cleanup:
JMF 12:0071cb144c7a 273
JMF 12:0071cb144c7a 274 if( ret != 0 )
JMF 12:0071cb144c7a 275 return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED + ret );
JMF 12:0071cb144c7a 276
JMF 12:0071cb144c7a 277 return( 0 );
JMF 12:0071cb144c7a 278 }
JMF 12:0071cb144c7a 279
JMF 12:0071cb144c7a 280 /*
JMF 12:0071cb144c7a 281 * Use the blinding method and optimisation suggested in section 10 of:
JMF 12:0071cb144c7a 282 * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
JMF 12:0071cb144c7a 283 * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer
JMF 12:0071cb144c7a 284 * Berlin Heidelberg, 1996. p. 104-113.
JMF 12:0071cb144c7a 285 */
JMF 12:0071cb144c7a 286 static int dhm_update_blinding( mbedtls_dhm_context *ctx,
JMF 12:0071cb144c7a 287 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
JMF 12:0071cb144c7a 288 {
JMF 12:0071cb144c7a 289 int ret, count;
JMF 12:0071cb144c7a 290
JMF 12:0071cb144c7a 291 /*
JMF 12:0071cb144c7a 292 * Don't use any blinding the first time a particular X is used,
JMF 12:0071cb144c7a 293 * but remember it to use blinding next time.
JMF 12:0071cb144c7a 294 */
JMF 12:0071cb144c7a 295 if( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->pX ) != 0 )
JMF 12:0071cb144c7a 296 {
JMF 12:0071cb144c7a 297 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &ctx->pX, &ctx->X ) );
JMF 12:0071cb144c7a 298 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vi, 1 ) );
JMF 12:0071cb144c7a 299 MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vf, 1 ) );
JMF 12:0071cb144c7a 300
JMF 12:0071cb144c7a 301 return( 0 );
JMF 12:0071cb144c7a 302 }
JMF 12:0071cb144c7a 303
JMF 12:0071cb144c7a 304 /*
JMF 12:0071cb144c7a 305 * Ok, we need blinding. Can we re-use existing values?
JMF 12:0071cb144c7a 306 * If yes, just update them by squaring them.
JMF 12:0071cb144c7a 307 */
JMF 12:0071cb144c7a 308 if( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 )
JMF 12:0071cb144c7a 309 {
JMF 12:0071cb144c7a 310 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
JMF 12:0071cb144c7a 311 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->P ) );
JMF 12:0071cb144c7a 312
JMF 12:0071cb144c7a 313 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
JMF 12:0071cb144c7a 314 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) );
JMF 12:0071cb144c7a 315
JMF 12:0071cb144c7a 316 return( 0 );
JMF 12:0071cb144c7a 317 }
JMF 12:0071cb144c7a 318
JMF 12:0071cb144c7a 319 /*
JMF 12:0071cb144c7a 320 * We need to generate blinding values from scratch
JMF 12:0071cb144c7a 321 */
JMF 12:0071cb144c7a 322
JMF 12:0071cb144c7a 323 /* Vi = random( 2, P-1 ) */
JMF 12:0071cb144c7a 324 count = 0;
JMF 12:0071cb144c7a 325 do
JMF 12:0071cb144c7a 326 {
JMF 12:0071cb144c7a 327 mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng );
JMF 12:0071cb144c7a 328
JMF 12:0071cb144c7a 329 while( mbedtls_mpi_cmp_mpi( &ctx->Vi, &ctx->P ) >= 0 )
JMF 12:0071cb144c7a 330 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->Vi, 1 ) );
JMF 12:0071cb144c7a 331
JMF 12:0071cb144c7a 332 if( count++ > 10 )
JMF 12:0071cb144c7a 333 return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE );
JMF 12:0071cb144c7a 334 }
JMF 12:0071cb144c7a 335 while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) <= 0 );
JMF 12:0071cb144c7a 336
JMF 12:0071cb144c7a 337 /* Vf = Vi^-X mod P */
JMF 12:0071cb144c7a 338 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vf, &ctx->Vi, &ctx->P ) );
JMF 12:0071cb144c7a 339 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP ) );
JMF 12:0071cb144c7a 340
JMF 12:0071cb144c7a 341 cleanup:
JMF 12:0071cb144c7a 342 return( ret );
JMF 12:0071cb144c7a 343 }
JMF 12:0071cb144c7a 344
JMF 12:0071cb144c7a 345 /*
JMF 12:0071cb144c7a 346 * Derive and export the shared secret (G^Y)^X mod P
JMF 12:0071cb144c7a 347 */
JMF 12:0071cb144c7a 348 int mbedtls_dhm_calc_secret( mbedtls_dhm_context *ctx,
JMF 12:0071cb144c7a 349 unsigned char *output, size_t output_size, size_t *olen,
JMF 12:0071cb144c7a 350 int (*f_rng)(void *, unsigned char *, size_t),
JMF 12:0071cb144c7a 351 void *p_rng )
JMF 12:0071cb144c7a 352 {
JMF 12:0071cb144c7a 353 int ret;
JMF 12:0071cb144c7a 354 mbedtls_mpi GYb;
JMF 12:0071cb144c7a 355
JMF 12:0071cb144c7a 356 if( ctx == NULL || output_size < ctx->len )
JMF 12:0071cb144c7a 357 return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
JMF 12:0071cb144c7a 358
JMF 12:0071cb144c7a 359 if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 )
JMF 12:0071cb144c7a 360 return( ret );
JMF 12:0071cb144c7a 361
JMF 12:0071cb144c7a 362 mbedtls_mpi_init( &GYb );
JMF 12:0071cb144c7a 363
JMF 12:0071cb144c7a 364 /* Blind peer's value */
JMF 12:0071cb144c7a 365 if( f_rng != NULL )
JMF 12:0071cb144c7a 366 {
JMF 12:0071cb144c7a 367 MBEDTLS_MPI_CHK( dhm_update_blinding( ctx, f_rng, p_rng ) );
JMF 12:0071cb144c7a 368 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &GYb, &ctx->GY, &ctx->Vi ) );
JMF 12:0071cb144c7a 369 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &GYb, &GYb, &ctx->P ) );
JMF 12:0071cb144c7a 370 }
JMF 12:0071cb144c7a 371 else
JMF 12:0071cb144c7a 372 MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &GYb, &ctx->GY ) );
JMF 12:0071cb144c7a 373
JMF 12:0071cb144c7a 374 /* Do modular exponentiation */
JMF 12:0071cb144c7a 375 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->K, &GYb, &ctx->X,
JMF 12:0071cb144c7a 376 &ctx->P, &ctx->RP ) );
JMF 12:0071cb144c7a 377
JMF 12:0071cb144c7a 378 /* Unblind secret value */
JMF 12:0071cb144c7a 379 if( f_rng != NULL )
JMF 12:0071cb144c7a 380 {
JMF 12:0071cb144c7a 381 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->K, &ctx->K, &ctx->Vf ) );
JMF 12:0071cb144c7a 382 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->K, &ctx->K, &ctx->P ) );
JMF 12:0071cb144c7a 383 }
JMF 12:0071cb144c7a 384
JMF 12:0071cb144c7a 385 *olen = mbedtls_mpi_size( &ctx->K );
JMF 12:0071cb144c7a 386
JMF 12:0071cb144c7a 387 MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->K, output, *olen ) );
JMF 12:0071cb144c7a 388
JMF 12:0071cb144c7a 389 cleanup:
JMF 12:0071cb144c7a 390 mbedtls_mpi_free( &GYb );
JMF 12:0071cb144c7a 391
JMF 12:0071cb144c7a 392 if( ret != 0 )
JMF 12:0071cb144c7a 393 return( MBEDTLS_ERR_DHM_CALC_SECRET_FAILED + ret );
JMF 12:0071cb144c7a 394
JMF 12:0071cb144c7a 395 return( 0 );
JMF 12:0071cb144c7a 396 }
JMF 12:0071cb144c7a 397
JMF 12:0071cb144c7a 398 /*
JMF 12:0071cb144c7a 399 * Free the components of a DHM key
JMF 12:0071cb144c7a 400 */
JMF 12:0071cb144c7a 401 void mbedtls_dhm_free( mbedtls_dhm_context *ctx )
JMF 12:0071cb144c7a 402 {
JMF 12:0071cb144c7a 403 mbedtls_mpi_free( &ctx->pX); mbedtls_mpi_free( &ctx->Vf ); mbedtls_mpi_free( &ctx->Vi );
JMF 12:0071cb144c7a 404 mbedtls_mpi_free( &ctx->RP ); mbedtls_mpi_free( &ctx->K ); mbedtls_mpi_free( &ctx->GY );
JMF 12:0071cb144c7a 405 mbedtls_mpi_free( &ctx->GX ); mbedtls_mpi_free( &ctx->X ); mbedtls_mpi_free( &ctx->G );
JMF 12:0071cb144c7a 406 mbedtls_mpi_free( &ctx->P );
JMF 12:0071cb144c7a 407
JMF 12:0071cb144c7a 408 mbedtls_zeroize( ctx, sizeof( mbedtls_dhm_context ) );
JMF 12:0071cb144c7a 409 }
JMF 12:0071cb144c7a 410
JMF 12:0071cb144c7a 411 #if defined(MBEDTLS_ASN1_PARSE_C)
JMF 12:0071cb144c7a 412 /*
JMF 12:0071cb144c7a 413 * Parse DHM parameters
JMF 12:0071cb144c7a 414 */
JMF 12:0071cb144c7a 415 int mbedtls_dhm_parse_dhm( mbedtls_dhm_context *dhm, const unsigned char *dhmin,
JMF 12:0071cb144c7a 416 size_t dhminlen )
JMF 12:0071cb144c7a 417 {
JMF 12:0071cb144c7a 418 int ret;
JMF 12:0071cb144c7a 419 size_t len;
JMF 12:0071cb144c7a 420 unsigned char *p, *end;
JMF 12:0071cb144c7a 421 #if defined(MBEDTLS_PEM_PARSE_C)
JMF 12:0071cb144c7a 422 mbedtls_pem_context pem;
JMF 12:0071cb144c7a 423
JMF 12:0071cb144c7a 424 mbedtls_pem_init( &pem );
JMF 12:0071cb144c7a 425
JMF 12:0071cb144c7a 426 /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */
JMF 12:0071cb144c7a 427 if( dhminlen == 0 || dhmin[dhminlen - 1] != '\0' )
JMF 12:0071cb144c7a 428 ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
JMF 12:0071cb144c7a 429 else
JMF 12:0071cb144c7a 430 ret = mbedtls_pem_read_buffer( &pem,
JMF 12:0071cb144c7a 431 "-----BEGIN DH PARAMETERS-----",
JMF 12:0071cb144c7a 432 "-----END DH PARAMETERS-----",
JMF 12:0071cb144c7a 433 dhmin, NULL, 0, &dhminlen );
JMF 12:0071cb144c7a 434
JMF 12:0071cb144c7a 435 if( ret == 0 )
JMF 12:0071cb144c7a 436 {
JMF 12:0071cb144c7a 437 /*
JMF 12:0071cb144c7a 438 * Was PEM encoded
JMF 12:0071cb144c7a 439 */
JMF 12:0071cb144c7a 440 dhminlen = pem.buflen;
JMF 12:0071cb144c7a 441 }
JMF 12:0071cb144c7a 442 else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
JMF 12:0071cb144c7a 443 goto exit;
JMF 12:0071cb144c7a 444
JMF 12:0071cb144c7a 445 p = ( ret == 0 ) ? pem.buf : (unsigned char *) dhmin;
JMF 12:0071cb144c7a 446 #else
JMF 12:0071cb144c7a 447 p = (unsigned char *) dhmin;
JMF 12:0071cb144c7a 448 #endif /* MBEDTLS_PEM_PARSE_C */
JMF 12:0071cb144c7a 449 end = p + dhminlen;
JMF 12:0071cb144c7a 450
JMF 12:0071cb144c7a 451 /*
JMF 12:0071cb144c7a 452 * DHParams ::= SEQUENCE {
JMF 12:0071cb144c7a 453 * prime INTEGER, -- P
JMF 12:0071cb144c7a 454 * generator INTEGER, -- g
JMF 12:0071cb144c7a 455 * privateValueLength INTEGER OPTIONAL
JMF 12:0071cb144c7a 456 * }
JMF 12:0071cb144c7a 457 */
JMF 12:0071cb144c7a 458 if( ( ret = mbedtls_asn1_get_tag( &p, end, &len,
JMF 12:0071cb144c7a 459 MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
JMF 12:0071cb144c7a 460 {
JMF 12:0071cb144c7a 461 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret;
JMF 12:0071cb144c7a 462 goto exit;
JMF 12:0071cb144c7a 463 }
JMF 12:0071cb144c7a 464
JMF 12:0071cb144c7a 465 end = p + len;
JMF 12:0071cb144c7a 466
JMF 12:0071cb144c7a 467 if( ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->P ) ) != 0 ||
JMF 12:0071cb144c7a 468 ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->G ) ) != 0 )
JMF 12:0071cb144c7a 469 {
JMF 12:0071cb144c7a 470 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret;
JMF 12:0071cb144c7a 471 goto exit;
JMF 12:0071cb144c7a 472 }
JMF 12:0071cb144c7a 473
JMF 12:0071cb144c7a 474 if( p != end )
JMF 12:0071cb144c7a 475 {
JMF 12:0071cb144c7a 476 /* This might be the optional privateValueLength.
JMF 12:0071cb144c7a 477 * If so, we can cleanly discard it */
JMF 12:0071cb144c7a 478 mbedtls_mpi rec;
JMF 12:0071cb144c7a 479 mbedtls_mpi_init( &rec );
JMF 12:0071cb144c7a 480 ret = mbedtls_asn1_get_mpi( &p, end, &rec );
JMF 12:0071cb144c7a 481 mbedtls_mpi_free( &rec );
JMF 12:0071cb144c7a 482 if ( ret != 0 )
JMF 12:0071cb144c7a 483 {
JMF 12:0071cb144c7a 484 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret;
JMF 12:0071cb144c7a 485 goto exit;
JMF 12:0071cb144c7a 486 }
JMF 12:0071cb144c7a 487 if ( p != end )
JMF 12:0071cb144c7a 488 {
JMF 12:0071cb144c7a 489 ret = MBEDTLS_ERR_DHM_INVALID_FORMAT +
JMF 12:0071cb144c7a 490 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH;
JMF 12:0071cb144c7a 491 goto exit;
JMF 12:0071cb144c7a 492 }
JMF 12:0071cb144c7a 493 }
JMF 12:0071cb144c7a 494
JMF 12:0071cb144c7a 495 ret = 0;
JMF 12:0071cb144c7a 496
JMF 12:0071cb144c7a 497 dhm->len = mbedtls_mpi_size( &dhm->P );
JMF 12:0071cb144c7a 498
JMF 12:0071cb144c7a 499 exit:
JMF 12:0071cb144c7a 500 #if defined(MBEDTLS_PEM_PARSE_C)
JMF 12:0071cb144c7a 501 mbedtls_pem_free( &pem );
JMF 12:0071cb144c7a 502 #endif
JMF 12:0071cb144c7a 503 if( ret != 0 )
JMF 12:0071cb144c7a 504 mbedtls_dhm_free( dhm );
JMF 12:0071cb144c7a 505
JMF 12:0071cb144c7a 506 return( ret );
JMF 12:0071cb144c7a 507 }
JMF 12:0071cb144c7a 508
JMF 12:0071cb144c7a 509 #if defined(MBEDTLS_FS_IO)
JMF 12:0071cb144c7a 510 /*
JMF 12:0071cb144c7a 511 * Load all data from a file into a given buffer.
JMF 12:0071cb144c7a 512 *
JMF 12:0071cb144c7a 513 * The file is expected to contain either PEM or DER encoded data.
JMF 12:0071cb144c7a 514 * A terminating null byte is always appended. It is included in the announced
JMF 12:0071cb144c7a 515 * length only if the data looks like it is PEM encoded.
JMF 12:0071cb144c7a 516 */
JMF 12:0071cb144c7a 517 static int load_file( const char *path, unsigned char **buf, size_t *n )
JMF 12:0071cb144c7a 518 {
JMF 12:0071cb144c7a 519 FILE *f;
JMF 12:0071cb144c7a 520 long size;
JMF 12:0071cb144c7a 521
JMF 12:0071cb144c7a 522 if( ( f = fopen( path, "rb" ) ) == NULL )
JMF 12:0071cb144c7a 523 return( MBEDTLS_ERR_DHM_FILE_IO_ERROR );
JMF 12:0071cb144c7a 524
JMF 12:0071cb144c7a 525 fseek( f, 0, SEEK_END );
JMF 12:0071cb144c7a 526 if( ( size = ftell( f ) ) == -1 )
JMF 12:0071cb144c7a 527 {
JMF 12:0071cb144c7a 528 fclose( f );
JMF 12:0071cb144c7a 529 return( MBEDTLS_ERR_DHM_FILE_IO_ERROR );
JMF 12:0071cb144c7a 530 }
JMF 12:0071cb144c7a 531 fseek( f, 0, SEEK_SET );
JMF 12:0071cb144c7a 532
JMF 12:0071cb144c7a 533 *n = (size_t) size;
JMF 12:0071cb144c7a 534
JMF 12:0071cb144c7a 535 if( *n + 1 == 0 ||
JMF 12:0071cb144c7a 536 ( *buf = mbedtls_calloc( 1, *n + 1 ) ) == NULL )
JMF 12:0071cb144c7a 537 {
JMF 12:0071cb144c7a 538 fclose( f );
JMF 12:0071cb144c7a 539 return( MBEDTLS_ERR_DHM_ALLOC_FAILED );
JMF 12:0071cb144c7a 540 }
JMF 12:0071cb144c7a 541
JMF 12:0071cb144c7a 542 if( fread( *buf, 1, *n, f ) != *n )
JMF 12:0071cb144c7a 543 {
JMF 12:0071cb144c7a 544 fclose( f );
JMF 12:0071cb144c7a 545 mbedtls_free( *buf );
JMF 12:0071cb144c7a 546 return( MBEDTLS_ERR_DHM_FILE_IO_ERROR );
JMF 12:0071cb144c7a 547 }
JMF 12:0071cb144c7a 548
JMF 12:0071cb144c7a 549 fclose( f );
JMF 12:0071cb144c7a 550
JMF 12:0071cb144c7a 551 (*buf)[*n] = '\0';
JMF 12:0071cb144c7a 552
JMF 12:0071cb144c7a 553 if( strstr( (const char *) *buf, "-----BEGIN " ) != NULL )
JMF 12:0071cb144c7a 554 ++*n;
JMF 12:0071cb144c7a 555
JMF 12:0071cb144c7a 556 return( 0 );
JMF 12:0071cb144c7a 557 }
JMF 12:0071cb144c7a 558
JMF 12:0071cb144c7a 559 /*
JMF 12:0071cb144c7a 560 * Load and parse DHM parameters
JMF 12:0071cb144c7a 561 */
JMF 12:0071cb144c7a 562 int mbedtls_dhm_parse_dhmfile( mbedtls_dhm_context *dhm, const char *path )
JMF 12:0071cb144c7a 563 {
JMF 12:0071cb144c7a 564 int ret;
JMF 12:0071cb144c7a 565 size_t n;
JMF 12:0071cb144c7a 566 unsigned char *buf;
JMF 12:0071cb144c7a 567
JMF 12:0071cb144c7a 568 if( ( ret = load_file( path, &buf, &n ) ) != 0 )
JMF 12:0071cb144c7a 569 return( ret );
JMF 12:0071cb144c7a 570
JMF 12:0071cb144c7a 571 ret = mbedtls_dhm_parse_dhm( dhm, buf, n );
JMF 12:0071cb144c7a 572
JMF 12:0071cb144c7a 573 mbedtls_zeroize( buf, n );
JMF 12:0071cb144c7a 574 mbedtls_free( buf );
JMF 12:0071cb144c7a 575
JMF 12:0071cb144c7a 576 return( ret );
JMF 12:0071cb144c7a 577 }
JMF 12:0071cb144c7a 578 #endif /* MBEDTLS_FS_IO */
JMF 12:0071cb144c7a 579 #endif /* MBEDTLS_ASN1_PARSE_C */
JMF 12:0071cb144c7a 580
JMF 12:0071cb144c7a 581 #if defined(MBEDTLS_SELF_TEST)
JMF 12:0071cb144c7a 582
JMF 12:0071cb144c7a 583 static const char mbedtls_test_dhm_params[] =
JMF 12:0071cb144c7a 584 "-----BEGIN DH PARAMETERS-----\r\n"
JMF 12:0071cb144c7a 585 "MIGHAoGBAJ419DBEOgmQTzo5qXl5fQcN9TN455wkOL7052HzxxRVMyhYmwQcgJvh\r\n"
JMF 12:0071cb144c7a 586 "1sa18fyfR9OiVEMYglOpkqVoGLN7qd5aQNNi5W7/C+VBdHTBJcGZJyyP5B3qcz32\r\n"
JMF 12:0071cb144c7a 587 "9mLJKudlVudV0Qxk5qUJaPZ/xupz0NyoVpviuiBOI1gNi8ovSXWzAgEC\r\n"
JMF 12:0071cb144c7a 588 "-----END DH PARAMETERS-----\r\n";
JMF 12:0071cb144c7a 589
JMF 12:0071cb144c7a 590 static const size_t mbedtls_test_dhm_params_len = sizeof( mbedtls_test_dhm_params );
JMF 12:0071cb144c7a 591
JMF 12:0071cb144c7a 592 /*
JMF 12:0071cb144c7a 593 * Checkup routine
JMF 12:0071cb144c7a 594 */
JMF 12:0071cb144c7a 595 int mbedtls_dhm_self_test( int verbose )
JMF 12:0071cb144c7a 596 {
JMF 12:0071cb144c7a 597 int ret;
JMF 12:0071cb144c7a 598 mbedtls_dhm_context dhm;
JMF 12:0071cb144c7a 599
JMF 12:0071cb144c7a 600 mbedtls_dhm_init( &dhm );
JMF 12:0071cb144c7a 601
JMF 12:0071cb144c7a 602 if( verbose != 0 )
JMF 12:0071cb144c7a 603 mbedtls_printf( " DHM parameter load: " );
JMF 12:0071cb144c7a 604
JMF 12:0071cb144c7a 605 if( ( ret = mbedtls_dhm_parse_dhm( &dhm,
JMF 12:0071cb144c7a 606 (const unsigned char *) mbedtls_test_dhm_params,
JMF 12:0071cb144c7a 607 mbedtls_test_dhm_params_len ) ) != 0 )
JMF 12:0071cb144c7a 608 {
JMF 12:0071cb144c7a 609 if( verbose != 0 )
JMF 12:0071cb144c7a 610 mbedtls_printf( "failed\n" );
JMF 12:0071cb144c7a 611
JMF 12:0071cb144c7a 612 ret = 1;
JMF 12:0071cb144c7a 613 goto exit;
JMF 12:0071cb144c7a 614 }
JMF 12:0071cb144c7a 615
JMF 12:0071cb144c7a 616 if( verbose != 0 )
JMF 12:0071cb144c7a 617 mbedtls_printf( "passed\n\n" );
JMF 12:0071cb144c7a 618
JMF 12:0071cb144c7a 619 exit:
JMF 12:0071cb144c7a 620 mbedtls_dhm_free( &dhm );
JMF 12:0071cb144c7a 621
JMF 12:0071cb144c7a 622 return( ret );
JMF 12:0071cb144c7a 623 }
JMF 12:0071cb144c7a 624
JMF 12:0071cb144c7a 625 #endif /* MBEDTLS_SELF_TEST */
JMF 12:0071cb144c7a 626
JMF 12:0071cb144c7a 627 #endif /* MBEDTLS_DHM_C */