Edison Ai | 7b07920 | 2018-02-28 15:01:47 +0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: Apache-2.0 |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 2 | /* |
| 3 | * Diffie-Hellman-Merkle key exchange |
| 4 | * |
| 5 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 6 | * |
| 7 | * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| 8 | * not use this file except in compliance with the License. |
| 9 | * You may obtain a copy of the License at |
| 10 | * |
| 11 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | * |
| 13 | * Unless required by applicable law or agreed to in writing, software |
| 14 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| 15 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | * See the License for the specific language governing permissions and |
| 17 | * limitations under the License. |
| 18 | * |
| 19 | * This file is part of mbed TLS (https://tls.mbed.org) |
| 20 | */ |
| 21 | /* |
| 22 | * The following sources were referenced in the design of this implementation |
| 23 | * of the Diffie-Hellman-Merkle algorithm: |
| 24 | * |
| 25 | * [1] Handbook of Applied Cryptography - 1997, Chapter 12 |
| 26 | * Menezes, van Oorschot and Vanstone |
| 27 | * |
| 28 | */ |
| 29 | |
| 30 | #if !defined(MBEDTLS_CONFIG_FILE) |
| 31 | #include "mbedtls/config.h" |
| 32 | #else |
| 33 | #include MBEDTLS_CONFIG_FILE |
| 34 | #endif |
| 35 | |
| 36 | #if defined(MBEDTLS_DHM_C) |
| 37 | |
| 38 | #include "mbedtls/dhm.h" |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 39 | #include "mbedtls/platform_util.h" |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 40 | |
| 41 | #include <string.h> |
| 42 | |
| 43 | #if defined(MBEDTLS_PEM_PARSE_C) |
| 44 | #include "mbedtls/pem.h" |
| 45 | #endif |
| 46 | |
| 47 | #if defined(MBEDTLS_ASN1_PARSE_C) |
| 48 | #include "mbedtls/asn1.h" |
| 49 | #endif |
| 50 | |
| 51 | #if defined(MBEDTLS_PLATFORM_C) |
| 52 | #include "mbedtls/platform.h" |
| 53 | #else |
| 54 | #include <stdlib.h> |
| 55 | #include <stdio.h> |
| 56 | #define mbedtls_printf printf |
| 57 | #define mbedtls_calloc calloc |
| 58 | #define mbedtls_free free |
| 59 | #endif |
| 60 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 61 | #if !defined(MBEDTLS_DHM_ALT) |
| 62 | |
| 63 | #define DHM_VALIDATE_RET( cond ) \ |
| 64 | MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_DHM_BAD_INPUT_DATA ) |
| 65 | #define DHM_VALIDATE( cond ) \ |
| 66 | MBEDTLS_INTERNAL_VALIDATE( cond ) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 67 | |
| 68 | /* |
| 69 | * helper to validate the mbedtls_mpi size and import it |
| 70 | */ |
| 71 | static int dhm_read_bignum( mbedtls_mpi *X, |
| 72 | unsigned char **p, |
| 73 | const unsigned char *end ) |
| 74 | { |
| 75 | int ret, n; |
| 76 | |
| 77 | if( end - *p < 2 ) |
| 78 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 79 | |
| 80 | n = ( (*p)[0] << 8 ) | (*p)[1]; |
| 81 | (*p) += 2; |
| 82 | |
| 83 | if( (int)( end - *p ) < n ) |
| 84 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 85 | |
| 86 | if( ( ret = mbedtls_mpi_read_binary( X, *p, n ) ) != 0 ) |
| 87 | return( MBEDTLS_ERR_DHM_READ_PARAMS_FAILED + ret ); |
| 88 | |
| 89 | (*p) += n; |
| 90 | |
| 91 | return( 0 ); |
| 92 | } |
| 93 | |
| 94 | /* |
| 95 | * Verify sanity of parameter with regards to P |
| 96 | * |
| 97 | * Parameter should be: 2 <= public_param <= P - 2 |
| 98 | * |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 99 | * This means that we need to return an error if |
| 100 | * public_param < 2 or public_param > P-2 |
| 101 | * |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 102 | * For more information on the attack, see: |
| 103 | * http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf |
| 104 | * http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643 |
| 105 | */ |
| 106 | static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P ) |
| 107 | { |
| 108 | mbedtls_mpi L, U; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 109 | int ret = 0; |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 110 | |
| 111 | mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U ); |
| 112 | |
| 113 | MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) ); |
| 114 | MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) ); |
| 115 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 116 | if( mbedtls_mpi_cmp_mpi( param, &L ) < 0 || |
| 117 | mbedtls_mpi_cmp_mpi( param, &U ) > 0 ) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 118 | { |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 119 | ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA; |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 120 | } |
| 121 | |
| 122 | cleanup: |
| 123 | mbedtls_mpi_free( &L ); mbedtls_mpi_free( &U ); |
| 124 | return( ret ); |
| 125 | } |
| 126 | |
| 127 | void mbedtls_dhm_init( mbedtls_dhm_context *ctx ) |
| 128 | { |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 129 | DHM_VALIDATE( ctx != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 130 | memset( ctx, 0, sizeof( mbedtls_dhm_context ) ); |
| 131 | } |
| 132 | |
| 133 | /* |
| 134 | * Parse the ServerKeyExchange parameters |
| 135 | */ |
| 136 | int mbedtls_dhm_read_params( mbedtls_dhm_context *ctx, |
| 137 | unsigned char **p, |
| 138 | const unsigned char *end ) |
| 139 | { |
| 140 | int ret; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 141 | DHM_VALIDATE_RET( ctx != NULL ); |
| 142 | DHM_VALIDATE_RET( p != NULL && *p != NULL ); |
| 143 | DHM_VALIDATE_RET( end != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 144 | |
| 145 | if( ( ret = dhm_read_bignum( &ctx->P, p, end ) ) != 0 || |
| 146 | ( ret = dhm_read_bignum( &ctx->G, p, end ) ) != 0 || |
| 147 | ( ret = dhm_read_bignum( &ctx->GY, p, end ) ) != 0 ) |
| 148 | return( ret ); |
| 149 | |
| 150 | if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 ) |
| 151 | return( ret ); |
| 152 | |
| 153 | ctx->len = mbedtls_mpi_size( &ctx->P ); |
| 154 | |
| 155 | return( 0 ); |
| 156 | } |
| 157 | |
| 158 | /* |
| 159 | * Setup and write the ServerKeyExchange parameters |
| 160 | */ |
| 161 | int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size, |
| 162 | unsigned char *output, size_t *olen, |
| 163 | int (*f_rng)(void *, unsigned char *, size_t), |
| 164 | void *p_rng ) |
| 165 | { |
| 166 | int ret, count = 0; |
| 167 | size_t n1, n2, n3; |
| 168 | unsigned char *p; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 169 | DHM_VALIDATE_RET( ctx != NULL ); |
| 170 | DHM_VALIDATE_RET( output != NULL ); |
| 171 | DHM_VALIDATE_RET( olen != NULL ); |
| 172 | DHM_VALIDATE_RET( f_rng != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 173 | |
| 174 | if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) |
| 175 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 176 | |
| 177 | /* |
| 178 | * Generate X as large as possible ( < P ) |
| 179 | */ |
| 180 | do |
| 181 | { |
| 182 | MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) ); |
| 183 | |
| 184 | while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 ) |
| 185 | MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) ); |
| 186 | |
| 187 | if( count++ > 10 ) |
| 188 | return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED ); |
| 189 | } |
| 190 | while( dhm_check_range( &ctx->X, &ctx->P ) != 0 ); |
| 191 | |
| 192 | /* |
| 193 | * Calculate GX = G^X mod P |
| 194 | */ |
| 195 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X, |
| 196 | &ctx->P , &ctx->RP ) ); |
| 197 | |
| 198 | if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 ) |
| 199 | return( ret ); |
| 200 | |
| 201 | /* |
| 202 | * export P, G, GX |
| 203 | */ |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 204 | #define DHM_MPI_EXPORT( X, n ) \ |
| 205 | do { \ |
| 206 | MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( ( X ), \ |
| 207 | p + 2, \ |
| 208 | ( n ) ) ); \ |
| 209 | *p++ = (unsigned char)( ( n ) >> 8 ); \ |
| 210 | *p++ = (unsigned char)( ( n ) ); \ |
| 211 | p += ( n ); \ |
| 212 | } while( 0 ) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 213 | |
| 214 | n1 = mbedtls_mpi_size( &ctx->P ); |
| 215 | n2 = mbedtls_mpi_size( &ctx->G ); |
| 216 | n3 = mbedtls_mpi_size( &ctx->GX ); |
| 217 | |
| 218 | p = output; |
| 219 | DHM_MPI_EXPORT( &ctx->P , n1 ); |
| 220 | DHM_MPI_EXPORT( &ctx->G , n2 ); |
| 221 | DHM_MPI_EXPORT( &ctx->GX, n3 ); |
| 222 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 223 | *olen = p - output; |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 224 | |
| 225 | ctx->len = n1; |
| 226 | |
| 227 | cleanup: |
| 228 | |
| 229 | if( ret != 0 ) |
| 230 | return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED + ret ); |
| 231 | |
| 232 | return( 0 ); |
| 233 | } |
| 234 | |
| 235 | /* |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 236 | * Set prime modulus and generator |
| 237 | */ |
| 238 | int mbedtls_dhm_set_group( mbedtls_dhm_context *ctx, |
| 239 | const mbedtls_mpi *P, |
| 240 | const mbedtls_mpi *G ) |
| 241 | { |
| 242 | int ret; |
| 243 | DHM_VALIDATE_RET( ctx != NULL ); |
| 244 | DHM_VALIDATE_RET( P != NULL ); |
| 245 | DHM_VALIDATE_RET( G != NULL ); |
| 246 | |
| 247 | if( ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 || |
| 248 | ( ret = mbedtls_mpi_copy( &ctx->G, G ) ) != 0 ) |
| 249 | { |
| 250 | return( MBEDTLS_ERR_DHM_SET_GROUP_FAILED + ret ); |
| 251 | } |
| 252 | |
| 253 | ctx->len = mbedtls_mpi_size( &ctx->P ); |
| 254 | return( 0 ); |
| 255 | } |
| 256 | |
| 257 | /* |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 258 | * Import the peer's public value G^Y |
| 259 | */ |
| 260 | int mbedtls_dhm_read_public( mbedtls_dhm_context *ctx, |
| 261 | const unsigned char *input, size_t ilen ) |
| 262 | { |
| 263 | int ret; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 264 | DHM_VALIDATE_RET( ctx != NULL ); |
| 265 | DHM_VALIDATE_RET( input != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 266 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 267 | if( ilen < 1 || ilen > ctx->len ) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 268 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 269 | |
| 270 | if( ( ret = mbedtls_mpi_read_binary( &ctx->GY, input, ilen ) ) != 0 ) |
| 271 | return( MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED + ret ); |
| 272 | |
| 273 | return( 0 ); |
| 274 | } |
| 275 | |
| 276 | /* |
| 277 | * Create own private value X and export G^X |
| 278 | */ |
| 279 | int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size, |
| 280 | unsigned char *output, size_t olen, |
| 281 | int (*f_rng)(void *, unsigned char *, size_t), |
| 282 | void *p_rng ) |
| 283 | { |
| 284 | int ret, count = 0; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 285 | DHM_VALIDATE_RET( ctx != NULL ); |
| 286 | DHM_VALIDATE_RET( output != NULL ); |
| 287 | DHM_VALIDATE_RET( f_rng != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 288 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 289 | if( olen < 1 || olen > ctx->len ) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 290 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 291 | |
| 292 | if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) |
| 293 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 294 | |
| 295 | /* |
| 296 | * generate X and calculate GX = G^X mod P |
| 297 | */ |
| 298 | do |
| 299 | { |
| 300 | MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) ); |
| 301 | |
| 302 | while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 ) |
| 303 | MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) ); |
| 304 | |
| 305 | if( count++ > 10 ) |
| 306 | return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED ); |
| 307 | } |
| 308 | while( dhm_check_range( &ctx->X, &ctx->P ) != 0 ); |
| 309 | |
| 310 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X, |
| 311 | &ctx->P , &ctx->RP ) ); |
| 312 | |
| 313 | if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 ) |
| 314 | return( ret ); |
| 315 | |
| 316 | MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) ); |
| 317 | |
| 318 | cleanup: |
| 319 | |
| 320 | if( ret != 0 ) |
| 321 | return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED + ret ); |
| 322 | |
| 323 | return( 0 ); |
| 324 | } |
| 325 | |
| 326 | /* |
| 327 | * Use the blinding method and optimisation suggested in section 10 of: |
| 328 | * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, |
| 329 | * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer |
| 330 | * Berlin Heidelberg, 1996. p. 104-113. |
| 331 | */ |
| 332 | static int dhm_update_blinding( mbedtls_dhm_context *ctx, |
| 333 | int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) |
| 334 | { |
| 335 | int ret, count; |
| 336 | |
| 337 | /* |
| 338 | * Don't use any blinding the first time a particular X is used, |
| 339 | * but remember it to use blinding next time. |
| 340 | */ |
| 341 | if( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->pX ) != 0 ) |
| 342 | { |
| 343 | MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &ctx->pX, &ctx->X ) ); |
| 344 | MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vi, 1 ) ); |
| 345 | MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vf, 1 ) ); |
| 346 | |
| 347 | return( 0 ); |
| 348 | } |
| 349 | |
| 350 | /* |
| 351 | * Ok, we need blinding. Can we re-use existing values? |
| 352 | * If yes, just update them by squaring them. |
| 353 | */ |
| 354 | if( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 ) |
| 355 | { |
| 356 | MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) ); |
| 357 | MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->P ) ); |
| 358 | |
| 359 | MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) ); |
| 360 | MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) ); |
| 361 | |
| 362 | return( 0 ); |
| 363 | } |
| 364 | |
| 365 | /* |
| 366 | * We need to generate blinding values from scratch |
| 367 | */ |
| 368 | |
| 369 | /* Vi = random( 2, P-1 ) */ |
| 370 | count = 0; |
| 371 | do |
| 372 | { |
| 373 | MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng ) ); |
| 374 | |
| 375 | while( mbedtls_mpi_cmp_mpi( &ctx->Vi, &ctx->P ) >= 0 ) |
| 376 | MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->Vi, 1 ) ); |
| 377 | |
| 378 | if( count++ > 10 ) |
| 379 | return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ); |
| 380 | } |
| 381 | while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) <= 0 ); |
| 382 | |
| 383 | /* Vf = Vi^-X mod P */ |
| 384 | MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vf, &ctx->Vi, &ctx->P ) ); |
| 385 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP ) ); |
| 386 | |
| 387 | cleanup: |
| 388 | return( ret ); |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * Derive and export the shared secret (G^Y)^X mod P |
| 393 | */ |
| 394 | int mbedtls_dhm_calc_secret( mbedtls_dhm_context *ctx, |
| 395 | unsigned char *output, size_t output_size, size_t *olen, |
| 396 | int (*f_rng)(void *, unsigned char *, size_t), |
| 397 | void *p_rng ) |
| 398 | { |
| 399 | int ret; |
| 400 | mbedtls_mpi GYb; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 401 | DHM_VALIDATE_RET( ctx != NULL ); |
| 402 | DHM_VALIDATE_RET( output != NULL ); |
| 403 | DHM_VALIDATE_RET( olen != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 404 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 405 | if( output_size < ctx->len ) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 406 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); |
| 407 | |
| 408 | if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 ) |
| 409 | return( ret ); |
| 410 | |
| 411 | mbedtls_mpi_init( &GYb ); |
| 412 | |
| 413 | /* Blind peer's value */ |
| 414 | if( f_rng != NULL ) |
| 415 | { |
| 416 | MBEDTLS_MPI_CHK( dhm_update_blinding( ctx, f_rng, p_rng ) ); |
| 417 | MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &GYb, &ctx->GY, &ctx->Vi ) ); |
| 418 | MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &GYb, &GYb, &ctx->P ) ); |
| 419 | } |
| 420 | else |
| 421 | MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &GYb, &ctx->GY ) ); |
| 422 | |
| 423 | /* Do modular exponentiation */ |
| 424 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->K, &GYb, &ctx->X, |
| 425 | &ctx->P, &ctx->RP ) ); |
| 426 | |
| 427 | /* Unblind secret value */ |
| 428 | if( f_rng != NULL ) |
| 429 | { |
| 430 | MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->K, &ctx->K, &ctx->Vf ) ); |
| 431 | MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->K, &ctx->K, &ctx->P ) ); |
| 432 | } |
| 433 | |
| 434 | *olen = mbedtls_mpi_size( &ctx->K ); |
| 435 | |
| 436 | MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->K, output, *olen ) ); |
| 437 | |
| 438 | cleanup: |
| 439 | mbedtls_mpi_free( &GYb ); |
| 440 | |
| 441 | if( ret != 0 ) |
| 442 | return( MBEDTLS_ERR_DHM_CALC_SECRET_FAILED + ret ); |
| 443 | |
| 444 | return( 0 ); |
| 445 | } |
| 446 | |
| 447 | /* |
| 448 | * Free the components of a DHM key |
| 449 | */ |
| 450 | void mbedtls_dhm_free( mbedtls_dhm_context *ctx ) |
| 451 | { |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 452 | if( ctx == NULL ) |
| 453 | return; |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 454 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 455 | mbedtls_mpi_free( &ctx->pX ); |
| 456 | mbedtls_mpi_free( &ctx->Vf ); |
| 457 | mbedtls_mpi_free( &ctx->Vi ); |
| 458 | mbedtls_mpi_free( &ctx->RP ); |
| 459 | mbedtls_mpi_free( &ctx->K ); |
| 460 | mbedtls_mpi_free( &ctx->GY ); |
| 461 | mbedtls_mpi_free( &ctx->GX ); |
| 462 | mbedtls_mpi_free( &ctx->X ); |
| 463 | mbedtls_mpi_free( &ctx->G ); |
| 464 | mbedtls_mpi_free( &ctx->P ); |
| 465 | |
| 466 | mbedtls_platform_zeroize( ctx, sizeof( mbedtls_dhm_context ) ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 467 | } |
| 468 | |
| 469 | #if defined(MBEDTLS_ASN1_PARSE_C) |
| 470 | /* |
| 471 | * Parse DHM parameters |
| 472 | */ |
| 473 | int mbedtls_dhm_parse_dhm( mbedtls_dhm_context *dhm, const unsigned char *dhmin, |
| 474 | size_t dhminlen ) |
| 475 | { |
| 476 | int ret; |
| 477 | size_t len; |
| 478 | unsigned char *p, *end; |
| 479 | #if defined(MBEDTLS_PEM_PARSE_C) |
| 480 | mbedtls_pem_context pem; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 481 | #endif /* MBEDTLS_PEM_PARSE_C */ |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 482 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 483 | DHM_VALIDATE_RET( dhm != NULL ); |
| 484 | DHM_VALIDATE_RET( dhmin != NULL ); |
| 485 | |
| 486 | #if defined(MBEDTLS_PEM_PARSE_C) |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 487 | mbedtls_pem_init( &pem ); |
| 488 | |
| 489 | /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */ |
| 490 | if( dhminlen == 0 || dhmin[dhminlen - 1] != '\0' ) |
| 491 | ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; |
| 492 | else |
| 493 | ret = mbedtls_pem_read_buffer( &pem, |
| 494 | "-----BEGIN DH PARAMETERS-----", |
| 495 | "-----END DH PARAMETERS-----", |
| 496 | dhmin, NULL, 0, &dhminlen ); |
| 497 | |
| 498 | if( ret == 0 ) |
| 499 | { |
| 500 | /* |
| 501 | * Was PEM encoded |
| 502 | */ |
| 503 | dhminlen = pem.buflen; |
| 504 | } |
| 505 | else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) |
| 506 | goto exit; |
| 507 | |
| 508 | p = ( ret == 0 ) ? pem.buf : (unsigned char *) dhmin; |
| 509 | #else |
| 510 | p = (unsigned char *) dhmin; |
| 511 | #endif /* MBEDTLS_PEM_PARSE_C */ |
| 512 | end = p + dhminlen; |
| 513 | |
| 514 | /* |
| 515 | * DHParams ::= SEQUENCE { |
| 516 | * prime INTEGER, -- P |
| 517 | * generator INTEGER, -- g |
| 518 | * privateValueLength INTEGER OPTIONAL |
| 519 | * } |
| 520 | */ |
| 521 | if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, |
| 522 | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) |
| 523 | { |
| 524 | ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret; |
| 525 | goto exit; |
| 526 | } |
| 527 | |
| 528 | end = p + len; |
| 529 | |
| 530 | if( ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->P ) ) != 0 || |
| 531 | ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->G ) ) != 0 ) |
| 532 | { |
| 533 | ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret; |
| 534 | goto exit; |
| 535 | } |
| 536 | |
| 537 | if( p != end ) |
| 538 | { |
| 539 | /* This might be the optional privateValueLength. |
| 540 | * If so, we can cleanly discard it */ |
| 541 | mbedtls_mpi rec; |
| 542 | mbedtls_mpi_init( &rec ); |
| 543 | ret = mbedtls_asn1_get_mpi( &p, end, &rec ); |
| 544 | mbedtls_mpi_free( &rec ); |
| 545 | if ( ret != 0 ) |
| 546 | { |
| 547 | ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + ret; |
| 548 | goto exit; |
| 549 | } |
| 550 | if ( p != end ) |
| 551 | { |
| 552 | ret = MBEDTLS_ERR_DHM_INVALID_FORMAT + |
| 553 | MBEDTLS_ERR_ASN1_LENGTH_MISMATCH; |
| 554 | goto exit; |
| 555 | } |
| 556 | } |
| 557 | |
| 558 | ret = 0; |
| 559 | |
| 560 | dhm->len = mbedtls_mpi_size( &dhm->P ); |
| 561 | |
| 562 | exit: |
| 563 | #if defined(MBEDTLS_PEM_PARSE_C) |
| 564 | mbedtls_pem_free( &pem ); |
| 565 | #endif |
| 566 | if( ret != 0 ) |
| 567 | mbedtls_dhm_free( dhm ); |
| 568 | |
| 569 | return( ret ); |
| 570 | } |
| 571 | |
| 572 | #if defined(MBEDTLS_FS_IO) |
| 573 | /* |
| 574 | * Load all data from a file into a given buffer. |
| 575 | * |
| 576 | * The file is expected to contain either PEM or DER encoded data. |
| 577 | * A terminating null byte is always appended. It is included in the announced |
| 578 | * length only if the data looks like it is PEM encoded. |
| 579 | */ |
| 580 | static int load_file( const char *path, unsigned char **buf, size_t *n ) |
| 581 | { |
| 582 | FILE *f; |
| 583 | long size; |
| 584 | |
| 585 | if( ( f = fopen( path, "rb" ) ) == NULL ) |
| 586 | return( MBEDTLS_ERR_DHM_FILE_IO_ERROR ); |
| 587 | |
| 588 | fseek( f, 0, SEEK_END ); |
| 589 | if( ( size = ftell( f ) ) == -1 ) |
| 590 | { |
| 591 | fclose( f ); |
| 592 | return( MBEDTLS_ERR_DHM_FILE_IO_ERROR ); |
| 593 | } |
| 594 | fseek( f, 0, SEEK_SET ); |
| 595 | |
| 596 | *n = (size_t) size; |
| 597 | |
| 598 | if( *n + 1 == 0 || |
| 599 | ( *buf = mbedtls_calloc( 1, *n + 1 ) ) == NULL ) |
| 600 | { |
| 601 | fclose( f ); |
| 602 | return( MBEDTLS_ERR_DHM_ALLOC_FAILED ); |
| 603 | } |
| 604 | |
| 605 | if( fread( *buf, 1, *n, f ) != *n ) |
| 606 | { |
| 607 | fclose( f ); |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 608 | |
| 609 | mbedtls_platform_zeroize( *buf, *n + 1 ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 610 | mbedtls_free( *buf ); |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 611 | |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 612 | return( MBEDTLS_ERR_DHM_FILE_IO_ERROR ); |
| 613 | } |
| 614 | |
| 615 | fclose( f ); |
| 616 | |
| 617 | (*buf)[*n] = '\0'; |
| 618 | |
| 619 | if( strstr( (const char *) *buf, "-----BEGIN " ) != NULL ) |
| 620 | ++*n; |
| 621 | |
| 622 | return( 0 ); |
| 623 | } |
| 624 | |
| 625 | /* |
| 626 | * Load and parse DHM parameters |
| 627 | */ |
| 628 | int mbedtls_dhm_parse_dhmfile( mbedtls_dhm_context *dhm, const char *path ) |
| 629 | { |
| 630 | int ret; |
| 631 | size_t n; |
| 632 | unsigned char *buf; |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 633 | DHM_VALIDATE_RET( dhm != NULL ); |
| 634 | DHM_VALIDATE_RET( path != NULL ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 635 | |
| 636 | if( ( ret = load_file( path, &buf, &n ) ) != 0 ) |
| 637 | return( ret ); |
| 638 | |
| 639 | ret = mbedtls_dhm_parse_dhm( dhm, buf, n ); |
| 640 | |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 641 | mbedtls_platform_zeroize( buf, n ); |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 642 | mbedtls_free( buf ); |
| 643 | |
| 644 | return( ret ); |
| 645 | } |
| 646 | #endif /* MBEDTLS_FS_IO */ |
| 647 | #endif /* MBEDTLS_ASN1_PARSE_C */ |
Jens Wiklander | 50a57cf | 2019-03-13 10:41:54 +0100 | [diff] [blame] | 648 | #endif /* MBEDTLS_DHM_ALT */ |
Jens Wiklander | 817466c | 2018-05-22 13:49:31 +0200 | [diff] [blame] | 649 | |
| 650 | #if defined(MBEDTLS_SELF_TEST) |
| 651 | |
| 652 | static const char mbedtls_test_dhm_params[] = |
| 653 | "-----BEGIN DH PARAMETERS-----\r\n" |
| 654 | "MIGHAoGBAJ419DBEOgmQTzo5qXl5fQcN9TN455wkOL7052HzxxRVMyhYmwQcgJvh\r\n" |
| 655 | "1sa18fyfR9OiVEMYglOpkqVoGLN7qd5aQNNi5W7/C+VBdHTBJcGZJyyP5B3qcz32\r\n" |
| 656 | "9mLJKudlVudV0Qxk5qUJaPZ/xupz0NyoVpviuiBOI1gNi8ovSXWzAgEC\r\n" |
| 657 | "-----END DH PARAMETERS-----\r\n"; |
| 658 | |
| 659 | static const size_t mbedtls_test_dhm_params_len = sizeof( mbedtls_test_dhm_params ); |
| 660 | |
| 661 | /* |
| 662 | * Checkup routine |
| 663 | */ |
| 664 | int mbedtls_dhm_self_test( int verbose ) |
| 665 | { |
| 666 | int ret; |
| 667 | mbedtls_dhm_context dhm; |
| 668 | |
| 669 | mbedtls_dhm_init( &dhm ); |
| 670 | |
| 671 | if( verbose != 0 ) |
| 672 | mbedtls_printf( " DHM parameter load: " ); |
| 673 | |
| 674 | if( ( ret = mbedtls_dhm_parse_dhm( &dhm, |
| 675 | (const unsigned char *) mbedtls_test_dhm_params, |
| 676 | mbedtls_test_dhm_params_len ) ) != 0 ) |
| 677 | { |
| 678 | if( verbose != 0 ) |
| 679 | mbedtls_printf( "failed\n" ); |
| 680 | |
| 681 | ret = 1; |
| 682 | goto exit; |
| 683 | } |
| 684 | |
| 685 | if( verbose != 0 ) |
| 686 | mbedtls_printf( "passed\n\n" ); |
| 687 | |
| 688 | exit: |
| 689 | mbedtls_dhm_free( &dhm ); |
| 690 | |
| 691 | return( ret ); |
| 692 | } |
| 693 | |
| 694 | #endif /* MBEDTLS_SELF_TEST */ |
| 695 | |
| 696 | #endif /* MBEDTLS_DHM_C */ |