[398] | 1 | /*
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| 2 | * Diffie-Hellman-Merkle key exchange
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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 | * The following sources were referenced in the design of this implementation
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| 23 | * of the Diffie-Hellman-Merkle algorithm:
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| 24 | *
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| 25 | * [1] Handbook of Applied Cryptography - 1997, Chapter 12
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| 26 | * Menezes, van Oorschot and Vanstone
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| 27 | *
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| 28 | */
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| 29 |
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| 30 | #if !defined(MBEDTLS_CONFIG_FILE)
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| 31 | #include "mbedtls/config.h"
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| 32 | #else
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| 33 | #include MBEDTLS_CONFIG_FILE
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| 34 | #endif
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| 35 |
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| 36 | #if defined(MBEDTLS_DHM_C)
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| 37 |
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| 38 | #include "mbedtls/dhm.h"
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| 39 | #include "mbedtls/platform_util.h"
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| 40 |
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| 41 | #include <string.h>
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| 42 |
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| 43 | #if defined(MBEDTLS_PEM_PARSE_C)
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| 44 | #include "mbedtls/pem.h"
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| 45 | #endif
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| 46 |
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| 47 | #if defined(MBEDTLS_ASN1_PARSE_C)
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| 48 | #include "mbedtls/asn1.h"
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| 49 | #endif
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| 50 |
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| 51 | #if defined(MBEDTLS_PLATFORM_C)
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| 52 | #include "mbedtls/platform.h"
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| 53 | #else
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| 54 | #include <stdlib.h>
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| 55 | #include <stdio.h>
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| 56 | #define mbedtls_printf printf
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| 57 | #define mbedtls_calloc calloc
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| 58 | #define mbedtls_free free
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| 59 | #endif
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| 60 |
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| 61 | #if !defined(MBEDTLS_DHM_ALT)
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| 62 |
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| 63 | #define DHM_VALIDATE_RET( cond ) \
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| 64 | MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_DHM_BAD_INPUT_DATA )
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| 65 | #define DHM_VALIDATE( cond ) \
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| 66 | MBEDTLS_INTERNAL_VALIDATE( cond )
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| 67 |
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| 68 | /*
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| 69 | * helper to validate the mbedtls_mpi size and import it
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| 70 | */
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| 71 | static int dhm_read_bignum( mbedtls_mpi *X,
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| 72 | unsigned char **p,
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| 73 | const unsigned char *end )
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| 74 | {
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| 75 | int ret, n;
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| 76 |
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| 77 | if( end - *p < 2 )
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| 78 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
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| 79 |
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| 80 | n = ( (*p)[0] << 8 ) | (*p)[1];
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| 81 | (*p) += 2;
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| 82 |
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| 83 | if( (int)( end - *p ) < n )
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| 84 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
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| 85 |
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| 86 | if( ( ret = mbedtls_mpi_read_binary( X, *p, n ) ) != 0 )
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| 87 | return( MBEDTLS_ERR_DHM_READ_PARAMS_FAILED + ret );
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| 88 |
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| 89 | (*p) += n;
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| 90 |
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| 91 | return( 0 );
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| 92 | }
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| 93 |
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| 94 | /*
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| 95 | * Verify sanity of parameter with regards to P
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| 96 | *
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| 97 | * Parameter should be: 2 <= public_param <= P - 2
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| 98 | *
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| 99 | * This means that we need to return an error if
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| 100 | * public_param < 2 or public_param > P-2
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| 101 | *
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| 102 | * For more information on the attack, see:
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| 103 | * http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf
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| 104 | * http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643
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| 105 | */
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| 106 | static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P )
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| 107 | {
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| 108 | mbedtls_mpi L, U;
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| 109 | int ret = 0;
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| 110 |
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| 111 | mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U );
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| 112 |
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| 113 | MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) );
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| 114 | MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) );
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| 115 |
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| 116 | if( mbedtls_mpi_cmp_mpi( param, &L ) < 0 ||
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| 117 | mbedtls_mpi_cmp_mpi( param, &U ) > 0 )
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| 118 | {
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| 119 | ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA;
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| 120 | }
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| 121 |
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| 122 | cleanup:
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| 123 | mbedtls_mpi_free( &L ); mbedtls_mpi_free( &U );
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| 124 | return( ret );
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| 125 | }
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| 126 |
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| 127 | void mbedtls_dhm_init( mbedtls_dhm_context *ctx )
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| 128 | {
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| 129 | DHM_VALIDATE( ctx != NULL );
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| 130 | memset( ctx, 0, sizeof( mbedtls_dhm_context ) );
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| 131 | }
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| 132 |
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| 133 | /*
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| 134 | * Parse the ServerKeyExchange parameters
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| 135 | */
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| 136 | int mbedtls_dhm_read_params( mbedtls_dhm_context *ctx,
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| 137 | unsigned char **p,
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| 138 | const unsigned char *end )
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| 139 | {
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| 140 | int ret;
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| 141 | DHM_VALIDATE_RET( ctx != NULL );
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| 142 | DHM_VALIDATE_RET( p != NULL && *p != NULL );
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| 143 | DHM_VALIDATE_RET( end != NULL );
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| 144 |
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| 145 | if( ( ret = dhm_read_bignum( &ctx->P, p, end ) ) != 0 ||
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| 146 | ( ret = dhm_read_bignum( &ctx->G, p, end ) ) != 0 ||
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| 147 | ( ret = dhm_read_bignum( &ctx->GY, p, end ) ) != 0 )
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| 148 | return( ret );
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| 149 |
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| 150 | if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 )
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| 151 | return( ret );
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| 152 |
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| 153 | ctx->len = mbedtls_mpi_size( &ctx->P );
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| 154 |
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| 155 | return( 0 );
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| 156 | }
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| 157 |
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| 158 | /*
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| 159 | * Setup and write the ServerKeyExchange parameters
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| 160 | */
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| 161 | int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size,
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| 162 | unsigned char *output, size_t *olen,
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| 163 | int (*f_rng)(void *, unsigned char *, size_t),
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| 164 | void *p_rng )
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| 165 | {
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| 166 | int ret, count = 0;
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| 167 | size_t n1, n2, n3;
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| 168 | unsigned char *p;
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| 169 | DHM_VALIDATE_RET( ctx != NULL );
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| 170 | DHM_VALIDATE_RET( output != NULL );
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| 171 | DHM_VALIDATE_RET( olen != NULL );
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| 172 | DHM_VALIDATE_RET( f_rng != NULL );
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| 173 |
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| 174 | if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 )
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| 175 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
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| 176 |
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| 177 | /*
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| 178 | * Generate X as large as possible ( < P )
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| 179 | */
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| 180 | do
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| 181 | {
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| 182 | MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) );
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| 183 |
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| 184 | while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
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| 185 | MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
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| 186 |
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| 187 | if( count++ > 10 )
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| 188 | return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED );
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| 189 | }
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| 190 | while( dhm_check_range( &ctx->X, &ctx->P ) != 0 );
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| 191 |
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| 192 | /*
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| 193 | * Calculate GX = G^X mod P
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| 194 | */
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| 195 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X,
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| 196 | &ctx->P , &ctx->RP ) );
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| 197 |
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| 198 | if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 )
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| 199 | return( ret );
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| 200 |
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| 201 | /*
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| 202 | * export P, G, GX
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| 203 | */
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| 204 | #define DHM_MPI_EXPORT( X, n ) \
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| 205 | do { \
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| 206 | MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( ( X ), \
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| 207 | p + 2, \
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| 208 | ( n ) ) ); \
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| 209 | *p++ = (unsigned char)( ( n ) >> 8 ); \
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| 210 | *p++ = (unsigned char)( ( n ) ); \
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| 211 | p += ( n ); \
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| 212 | } while( 0 )
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| 213 |
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| 214 | n1 = mbedtls_mpi_size( &ctx->P );
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| 215 | n2 = mbedtls_mpi_size( &ctx->G );
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| 216 | n3 = mbedtls_mpi_size( &ctx->GX );
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| 217 |
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| 218 | p = output;
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| 219 | DHM_MPI_EXPORT( &ctx->P , n1 );
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| 220 | DHM_MPI_EXPORT( &ctx->G , n2 );
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| 221 | DHM_MPI_EXPORT( &ctx->GX, n3 );
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| 222 |
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| 223 | *olen = p - output;
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| 224 |
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| 225 | ctx->len = n1;
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| 226 |
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| 227 | cleanup:
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| 228 |
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| 229 | if( ret != 0 )
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| 230 | return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED + ret );
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| 231 |
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| 232 | return( 0 );
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| 233 | }
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| 234 |
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| 235 | /*
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| 236 | * Set prime modulus and generator
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| 237 | */
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| 238 | int mbedtls_dhm_set_group( mbedtls_dhm_context *ctx,
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| 239 | const mbedtls_mpi *P,
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| 240 | const mbedtls_mpi *G )
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| 241 | {
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| 242 | int ret;
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| 243 | DHM_VALIDATE_RET( ctx != NULL );
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| 244 | DHM_VALIDATE_RET( P != NULL );
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| 245 | DHM_VALIDATE_RET( G != NULL );
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| 246 |
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| 247 | if( ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 ||
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| 248 | ( ret = mbedtls_mpi_copy( &ctx->G, G ) ) != 0 )
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| 249 | {
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| 250 | return( MBEDTLS_ERR_DHM_SET_GROUP_FAILED + ret );
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| 251 | }
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| 252 |
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| 253 | ctx->len = mbedtls_mpi_size( &ctx->P );
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| 254 | return( 0 );
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| 255 | }
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| 256 |
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| 257 | /*
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| 258 | * Import the peer's public value G^Y
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| 259 | */
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| 260 | int mbedtls_dhm_read_public( mbedtls_dhm_context *ctx,
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| 261 | const unsigned char *input, size_t ilen )
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| 262 | {
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| 263 | int ret;
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| 264 | DHM_VALIDATE_RET( ctx != NULL );
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| 265 | DHM_VALIDATE_RET( input != NULL );
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| 266 |
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| 267 | if( ilen < 1 || ilen > ctx->len )
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| 268 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
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| 269 |
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| 270 | if( ( ret = mbedtls_mpi_read_binary( &ctx->GY, input, ilen ) ) != 0 )
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| 271 | return( MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED + ret );
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| 272 |
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| 273 | return( 0 );
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| 274 | }
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| 275 |
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| 276 | /*
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| 277 | * Create own private value X and export G^X
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| 278 | */
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| 279 | int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size,
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| 280 | unsigned char *output, size_t olen,
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| 281 | int (*f_rng)(void *, unsigned char *, size_t),
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| 282 | void *p_rng )
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| 283 | {
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| 284 | int ret, count = 0;
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| 285 | DHM_VALIDATE_RET( ctx != NULL );
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| 286 | DHM_VALIDATE_RET( output != NULL );
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| 287 | DHM_VALIDATE_RET( f_rng != NULL );
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| 288 |
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| 289 | if( olen < 1 || olen > ctx->len )
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| 290 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
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| 291 |
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| 292 | if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 )
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| 293 | return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA );
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| 294 |
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| 295 | /*
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| 296 | * generate X and calculate GX = G^X mod P
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| 297 | */
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| 298 | do
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| 299 | {
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| 300 | MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) );
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| 301 |
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| 302 | while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 )
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| 303 | MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) );
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| 304 |
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| 305 | if( count++ > 10 )
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| 306 | return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED );
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| 307 | }
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| 308 | while( dhm_check_range( &ctx->X, &ctx->P ) != 0 );
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| 309 |
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| 310 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X,
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| 311 | &ctx->P , &ctx->RP ) );
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| 312 |
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| 313 | if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 )
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| 314 | return( ret );
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| 315 |
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| 316 | MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) );
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| 317 |
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| 318 | cleanup:
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| 319 |
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| 320 | if( ret != 0 )
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| 321 | return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED + ret );
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| 322 |
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| 323 | return( 0 );
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| 324 | }
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| 325 |
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| 326 | /*
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| 327 | * Use the blinding method and optimisation suggested in section 10 of:
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| 328 | * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA,
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| 329 | * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer
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| 330 | * Berlin Heidelberg, 1996. p. 104-113.
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| 331 | */
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| 332 | static int dhm_update_blinding( mbedtls_dhm_context *ctx,
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| 333 | int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
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| 334 | {
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| 335 | int ret, count;
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| 336 |
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| 337 | /*
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| 338 | * Don't use any blinding the first time a particular X is used,
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| 339 | * but remember it to use blinding next time.
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| 340 | */
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| 341 | if( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->pX ) != 0 )
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| 342 | {
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| 343 | MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &ctx->pX, &ctx->X ) );
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| 344 | MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vi, 1 ) );
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| 345 | MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vf, 1 ) );
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| 346 |
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| 347 | return( 0 );
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| 348 | }
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| 349 |
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| 350 | /*
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| 351 | * Ok, we need blinding. Can we re-use existing values?
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| 352 | * If yes, just update them by squaring them.
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| 353 | */
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| 354 | if( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 )
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| 355 | {
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| 356 | MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) );
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| 357 | MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->P ) );
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| 358 |
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| 359 | MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) );
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| 360 | MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) );
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| 361 |
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| 362 | return( 0 );
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| 363 | }
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| 364 |
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| 365 | /*
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| 366 | * We need to generate blinding values from scratch
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| 367 | */
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| 368 |
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| 369 | /* Vi = random( 2, P-1 ) */
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| 370 | count = 0;
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| 371 | do
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| 372 | {
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| 373 | MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng ) );
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| 374 |
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| 375 | while( mbedtls_mpi_cmp_mpi( &ctx->Vi, &ctx->P ) >= 0 )
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| 376 | MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->Vi, 1 ) );
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| 377 |
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| 378 | if( count++ > 10 )
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| 379 | return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE );
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| 380 | }
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| 381 | while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) <= 0 );
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| 382 |
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| 383 | /* Vf = Vi^-X mod P */
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| 384 | MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vf, &ctx->Vi, &ctx->P ) );
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| 385 | MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP ) );
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| 386 |
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| 387 | cleanup:
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| 388 | return( ret );
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| 389 | }
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| 390 |
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| 391 | /*
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| 392 | * Derive and export the shared secret (G^Y)^X mod P
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| 393 | */
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| 394 | int mbedtls_dhm_calc_secret( mbedtls_dhm_context *ctx,
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| 395 | unsigned char *output, size_t output_size, size_t *olen,
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| 396 | int (*f_rng)(void *, unsigned char *, size_t),
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| 397 | void *p_rng )
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| 398 | {
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| 399 | int ret;
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| 400 | mbedtls_mpi GYb;
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| 401 | DHM_VALIDATE_RET( ctx != NULL );
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| 402 | DHM_VALIDATE_RET( output != NULL );
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| 403 | DHM_VALIDATE_RET( olen != NULL );
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| 404 |
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| 405 | if( output_size < ctx->len )
|
---|
| 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 | {
|
---|
| 452 | if( ctx == NULL )
|
---|
| 453 | return;
|
---|
| 454 |
|
---|
| 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 ) );
|
---|
| 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;
|
---|
| 481 | #endif /* MBEDTLS_PEM_PARSE_C */
|
---|
| 482 |
|
---|
| 483 | DHM_VALIDATE_RET( dhm != NULL );
|
---|
| 484 | DHM_VALIDATE_RET( dhmin != NULL );
|
---|
| 485 |
|
---|
| 486 | #if defined(MBEDTLS_PEM_PARSE_C)
|
---|
| 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 );
|
---|
| 608 |
|
---|
| 609 | mbedtls_platform_zeroize( *buf, *n + 1 );
|
---|
| 610 | mbedtls_free( *buf );
|
---|
| 611 |
|
---|
| 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;
|
---|
| 633 | DHM_VALIDATE_RET( dhm != NULL );
|
---|
| 634 | DHM_VALIDATE_RET( path != NULL );
|
---|
| 635 |
|
---|
| 636 | if( ( ret = load_file( path, &buf, &n ) ) != 0 )
|
---|
| 637 | return( ret );
|
---|
| 638 |
|
---|
| 639 | ret = mbedtls_dhm_parse_dhm( dhm, buf, n );
|
---|
| 640 |
|
---|
| 641 | mbedtls_platform_zeroize( buf, n );
|
---|
| 642 | mbedtls_free( buf );
|
---|
| 643 |
|
---|
| 644 | return( ret );
|
---|
| 645 | }
|
---|
| 646 | #endif /* MBEDTLS_FS_IO */
|
---|
| 647 | #endif /* MBEDTLS_ASN1_PARSE_C */
|
---|
| 648 | #endif /* MBEDTLS_DHM_ALT */
|
---|
| 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 */
|
---|