Kev Mann / mbed-dev-OS5_10_4

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features/mbedtls/src/rsa_internal.c@0:38ceb79fef03, 2018-11-28 (annotated)

Committer:
kevman
Date:
Wed Nov 28 15:10:15 2018 +0000
Revision:
0:38ceb79fef03
RTC modified

Who changed what in which revision?

UserRevisionLine numberNew contents of line
kevman 0:38ceb79fef03 1 /*
kevman 0:38ceb79fef03 2 * Helper functions for the RSA module
kevman 0:38ceb79fef03 3 *
kevman 0:38ceb79fef03 4 * Copyright (C) 2006-2017, ARM Limited, All Rights Reserved
kevman 0:38ceb79fef03 5 * SPDX-License-Identifier: Apache-2.0
kevman 0:38ceb79fef03 6 *
kevman 0:38ceb79fef03 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
kevman 0:38ceb79fef03 8 * not use this file except in compliance with the License.
kevman 0:38ceb79fef03 9 * You may obtain a copy of the License at
kevman 0:38ceb79fef03 10 *
kevman 0:38ceb79fef03 11 * http://www.apache.org/licenses/LICENSE-2.0
kevman 0:38ceb79fef03 12 *
kevman 0:38ceb79fef03 13 * Unless required by applicable law or agreed to in writing, software
kevman 0:38ceb79fef03 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
kevman 0:38ceb79fef03 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
kevman 0:38ceb79fef03 16 * See the License for the specific language governing permissions and
kevman 0:38ceb79fef03 17 * limitations under the License.
kevman 0:38ceb79fef03 18 *
kevman 0:38ceb79fef03 19 * This file is part of mbed TLS (https://tls.mbed.org)
kevman 0:38ceb79fef03 20 *
kevman 0:38ceb79fef03 21 */
kevman 0:38ceb79fef03 22
kevman 0:38ceb79fef03 23 #if !defined(MBEDTLS_CONFIG_FILE)
kevman 0:38ceb79fef03 24 #include "mbedtls/config.h"
kevman 0:38ceb79fef03 25 #else
kevman 0:38ceb79fef03 26 #include MBEDTLS_CONFIG_FILE
kevman 0:38ceb79fef03 27 #endif
kevman 0:38ceb79fef03 28
kevman 0:38ceb79fef03 29 #if defined(MBEDTLS_RSA_C)
kevman 0:38ceb79fef03 30
kevman 0:38ceb79fef03 31 #include "mbedtls/rsa.h"
kevman 0:38ceb79fef03 32 #include "mbedtls/bignum.h"
kevman 0:38ceb79fef03 33 #include "mbedtls/rsa_internal.h"
kevman 0:38ceb79fef03 34
kevman 0:38ceb79fef03 35 /*
kevman 0:38ceb79fef03 36 * Compute RSA prime factors from public and private exponents
kevman 0:38ceb79fef03 37 *
kevman 0:38ceb79fef03 38 * Summary of algorithm:
kevman 0:38ceb79fef03 39 * Setting F := lcm(P-1,Q-1), the idea is as follows:
kevman 0:38ceb79fef03 40 *
kevman 0:38ceb79fef03 41 * (a) For any 1 <= X < N with gcd(X,N)=1, we have X^F = 1 modulo N, so X^(F/2)
kevman 0:38ceb79fef03 42 * is a square root of 1 in Z/NZ. Since Z/NZ ~= Z/PZ x Z/QZ by CRT and the
kevman 0:38ceb79fef03 43 * square roots of 1 in Z/PZ and Z/QZ are +1 and -1, this leaves the four
kevman 0:38ceb79fef03 44 * possibilities X^(F/2) = (+-1, +-1). If it happens that X^(F/2) = (-1,+1)
kevman 0:38ceb79fef03 45 * or (+1,-1), then gcd(X^(F/2) + 1, N) will be equal to one of the prime
kevman 0:38ceb79fef03 46 * factors of N.
kevman 0:38ceb79fef03 47 *
kevman 0:38ceb79fef03 48 * (b) If we don't know F/2 but (F/2) * K for some odd (!) K, then the same
kevman 0:38ceb79fef03 49 * construction still applies since (-)^K is the identity on the set of
kevman 0:38ceb79fef03 50 * roots of 1 in Z/NZ.
kevman 0:38ceb79fef03 51 *
kevman 0:38ceb79fef03 52 * The public and private key primitives (-)^E and (-)^D are mutually inverse
kevman 0:38ceb79fef03 53 * bijections on Z/NZ if and only if (-)^(DE) is the identity on Z/NZ, i.e.
kevman 0:38ceb79fef03 54 * if and only if DE - 1 is a multiple of F, say DE - 1 = F * L.
kevman 0:38ceb79fef03 55 * Splitting L = 2^t * K with K odd, we have
kevman 0:38ceb79fef03 56 *
kevman 0:38ceb79fef03 57 * DE - 1 = FL = (F/2) * (2^(t+1)) * K,
kevman 0:38ceb79fef03 58 *
kevman 0:38ceb79fef03 59 * so (F / 2) * K is among the numbers
kevman 0:38ceb79fef03 60 *
kevman 0:38ceb79fef03 61 * (DE - 1) >> 1, (DE - 1) >> 2, ..., (DE - 1) >> ord
kevman 0:38ceb79fef03 62 *
kevman 0:38ceb79fef03 63 * where ord is the order of 2 in (DE - 1).
kevman 0:38ceb79fef03 64 * We can therefore iterate through these numbers apply the construction
kevman 0:38ceb79fef03 65 * of (a) and (b) above to attempt to factor N.
kevman 0:38ceb79fef03 66 *
kevman 0:38ceb79fef03 67 */
kevman 0:38ceb79fef03 68 int mbedtls_rsa_deduce_primes( mbedtls_mpi const *N,
kevman 0:38ceb79fef03 69 mbedtls_mpi const *E, mbedtls_mpi const *D,
kevman 0:38ceb79fef03 70 mbedtls_mpi *P, mbedtls_mpi *Q )
kevman 0:38ceb79fef03 71 {
kevman 0:38ceb79fef03 72 int ret = 0;
kevman 0:38ceb79fef03 73
kevman 0:38ceb79fef03 74 uint16_t attempt; /* Number of current attempt */
kevman 0:38ceb79fef03 75 uint16_t iter; /* Number of squares computed in the current attempt */
kevman 0:38ceb79fef03 76
kevman 0:38ceb79fef03 77 uint16_t order; /* Order of 2 in DE - 1 */
kevman 0:38ceb79fef03 78
kevman 0:38ceb79fef03 79 mbedtls_mpi T; /* Holds largest odd divisor of DE - 1 */
kevman 0:38ceb79fef03 80 mbedtls_mpi K; /* Temporary holding the current candidate */
kevman 0:38ceb79fef03 81
kevman 0:38ceb79fef03 82 const unsigned char primes[] = { 2,
kevman 0:38ceb79fef03 83 3, 5, 7, 11, 13, 17, 19, 23,
kevman 0:38ceb79fef03 84 29, 31, 37, 41, 43, 47, 53, 59,
kevman 0:38ceb79fef03 85 61, 67, 71, 73, 79, 83, 89, 97,
kevman 0:38ceb79fef03 86 101, 103, 107, 109, 113, 127, 131, 137,
kevman 0:38ceb79fef03 87 139, 149, 151, 157, 163, 167, 173, 179,
kevman 0:38ceb79fef03 88 181, 191, 193, 197, 199, 211, 223, 227,
kevman 0:38ceb79fef03 89 229, 233, 239, 241, 251
kevman 0:38ceb79fef03 90 };
kevman 0:38ceb79fef03 91
kevman 0:38ceb79fef03 92 const size_t num_primes = sizeof( primes ) / sizeof( *primes );
kevman 0:38ceb79fef03 93
kevman 0:38ceb79fef03 94 if( P == NULL || Q == NULL || P->p != NULL || Q->p != NULL )
kevman 0:38ceb79fef03 95 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
kevman 0:38ceb79fef03 96
kevman 0:38ceb79fef03 97 if( mbedtls_mpi_cmp_int( N, 0 ) <= 0 ||
kevman 0:38ceb79fef03 98 mbedtls_mpi_cmp_int( D, 1 ) <= 0 ||
kevman 0:38ceb79fef03 99 mbedtls_mpi_cmp_mpi( D, N ) >= 0 ||
kevman 0:38ceb79fef03 100 mbedtls_mpi_cmp_int( E, 1 ) <= 0 ||
kevman 0:38ceb79fef03 101 mbedtls_mpi_cmp_mpi( E, N ) >= 0 )
kevman 0:38ceb79fef03 102 {
kevman 0:38ceb79fef03 103 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
kevman 0:38ceb79fef03 104 }
kevman 0:38ceb79fef03 105
kevman 0:38ceb79fef03 106 /*
kevman 0:38ceb79fef03 107 * Initializations and temporary changes
kevman 0:38ceb79fef03 108 */
kevman 0:38ceb79fef03 109
kevman 0:38ceb79fef03 110 mbedtls_mpi_init( &K );
kevman 0:38ceb79fef03 111 mbedtls_mpi_init( &T );
kevman 0:38ceb79fef03 112
kevman 0:38ceb79fef03 113 /* T := DE - 1 */
kevman 0:38ceb79fef03 114 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, D, E ) );
kevman 0:38ceb79fef03 115 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &T, &T, 1 ) );
kevman 0:38ceb79fef03 116
kevman 0:38ceb79fef03 117 if( ( order = (uint16_t) mbedtls_mpi_lsb( &T ) ) == 0 )
kevman 0:38ceb79fef03 118 {
kevman 0:38ceb79fef03 119 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
kevman 0:38ceb79fef03 120 goto cleanup;
kevman 0:38ceb79fef03 121 }
kevman 0:38ceb79fef03 122
kevman 0:38ceb79fef03 123 /* After this operation, T holds the largest odd divisor of DE - 1. */
kevman 0:38ceb79fef03 124 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &T, order ) );
kevman 0:38ceb79fef03 125
kevman 0:38ceb79fef03 126 /*
kevman 0:38ceb79fef03 127 * Actual work
kevman 0:38ceb79fef03 128 */
kevman 0:38ceb79fef03 129
kevman 0:38ceb79fef03 130 /* Skip trying 2 if N == 1 mod 8 */
kevman 0:38ceb79fef03 131 attempt = 0;
kevman 0:38ceb79fef03 132 if( N->p[0] % 8 == 1 )
kevman 0:38ceb79fef03 133 attempt = 1;
kevman 0:38ceb79fef03 134
kevman 0:38ceb79fef03 135 for( ; attempt < num_primes; ++attempt )
kevman 0:38ceb79fef03 136 {
kevman 0:38ceb79fef03 137 mbedtls_mpi_lset( &K, primes[attempt] );
kevman 0:38ceb79fef03 138
kevman 0:38ceb79fef03 139 /* Check if gcd(K,N) = 1 */
kevman 0:38ceb79fef03 140 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( P, &K, N ) );
kevman 0:38ceb79fef03 141 if( mbedtls_mpi_cmp_int( P, 1 ) != 0 )
kevman 0:38ceb79fef03 142 continue;
kevman 0:38ceb79fef03 143
kevman 0:38ceb79fef03 144 /* Go through K^T + 1, K^(2T) + 1, K^(4T) + 1, ...
kevman 0:38ceb79fef03 145 * and check whether they have nontrivial GCD with N. */
kevman 0:38ceb79fef03 146 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &K, &K, &T, N,
kevman 0:38ceb79fef03 147 Q /* temporarily use Q for storing Montgomery
kevman 0:38ceb79fef03 148 * multiplication helper values */ ) );
kevman 0:38ceb79fef03 149
kevman 0:38ceb79fef03 150 for( iter = 1; iter <= order; ++iter )
kevman 0:38ceb79fef03 151 {
kevman 0:38ceb79fef03 152 /* If we reach 1 prematurely, there's no point
kevman 0:38ceb79fef03 153 * in continuing to square K */
kevman 0:38ceb79fef03 154 if( mbedtls_mpi_cmp_int( &K, 1 ) == 0 )
kevman 0:38ceb79fef03 155 break;
kevman 0:38ceb79fef03 156
kevman 0:38ceb79fef03 157 MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &K, &K, 1 ) );
kevman 0:38ceb79fef03 158 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( P, &K, N ) );
kevman 0:38ceb79fef03 159
kevman 0:38ceb79fef03 160 if( mbedtls_mpi_cmp_int( P, 1 ) == 1 &&
kevman 0:38ceb79fef03 161 mbedtls_mpi_cmp_mpi( P, N ) == -1 )
kevman 0:38ceb79fef03 162 {
kevman 0:38ceb79fef03 163 /*
kevman 0:38ceb79fef03 164 * Have found a nontrivial divisor P of N.
kevman 0:38ceb79fef03 165 * Set Q := N / P.
kevman 0:38ceb79fef03 166 */
kevman 0:38ceb79fef03 167
kevman 0:38ceb79fef03 168 MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( Q, NULL, N, P ) );
kevman 0:38ceb79fef03 169 goto cleanup;
kevman 0:38ceb79fef03 170 }
kevman 0:38ceb79fef03 171
kevman 0:38ceb79fef03 172 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
kevman 0:38ceb79fef03 173 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, &K, &K ) );
kevman 0:38ceb79fef03 174 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, N ) );
kevman 0:38ceb79fef03 175 }
kevman 0:38ceb79fef03 176
kevman 0:38ceb79fef03 177 /*
kevman 0:38ceb79fef03 178 * If we get here, then either we prematurely aborted the loop because
kevman 0:38ceb79fef03 179 * we reached 1, or K holds primes[attempt]^(DE - 1) mod N, which must
kevman 0:38ceb79fef03 180 * be 1 if D,E,N were consistent.
kevman 0:38ceb79fef03 181 * Check if that's the case and abort if not, to avoid very long,
kevman 0:38ceb79fef03 182 * yet eventually failing, computations if N,D,E were not sane.
kevman 0:38ceb79fef03 183 */
kevman 0:38ceb79fef03 184 if( mbedtls_mpi_cmp_int( &K, 1 ) != 0 )
kevman 0:38ceb79fef03 185 {
kevman 0:38ceb79fef03 186 break;
kevman 0:38ceb79fef03 187 }
kevman 0:38ceb79fef03 188 }
kevman 0:38ceb79fef03 189
kevman 0:38ceb79fef03 190 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
kevman 0:38ceb79fef03 191
kevman 0:38ceb79fef03 192 cleanup:
kevman 0:38ceb79fef03 193
kevman 0:38ceb79fef03 194 mbedtls_mpi_free( &K );
kevman 0:38ceb79fef03 195 mbedtls_mpi_free( &T );
kevman 0:38ceb79fef03 196 return( ret );
kevman 0:38ceb79fef03 197 }
kevman 0:38ceb79fef03 198
kevman 0:38ceb79fef03 199 /*
kevman 0:38ceb79fef03 200 * Given P, Q and the public exponent E, deduce D.
kevman 0:38ceb79fef03 201 * This is essentially a modular inversion.
kevman 0:38ceb79fef03 202 */
kevman 0:38ceb79fef03 203 int mbedtls_rsa_deduce_private_exponent( mbedtls_mpi const *P,
kevman 0:38ceb79fef03 204 mbedtls_mpi const *Q,
kevman 0:38ceb79fef03 205 mbedtls_mpi const *E,
kevman 0:38ceb79fef03 206 mbedtls_mpi *D )
kevman 0:38ceb79fef03 207 {
kevman 0:38ceb79fef03 208 int ret = 0;
kevman 0:38ceb79fef03 209 mbedtls_mpi K, L;
kevman 0:38ceb79fef03 210
kevman 0:38ceb79fef03 211 if( D == NULL || mbedtls_mpi_cmp_int( D, 0 ) != 0 )
kevman 0:38ceb79fef03 212 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
kevman 0:38ceb79fef03 213
kevman 0:38ceb79fef03 214 if( mbedtls_mpi_cmp_int( P, 1 ) <= 0 ||
kevman 0:38ceb79fef03 215 mbedtls_mpi_cmp_int( Q, 1 ) <= 0 ||
kevman 0:38ceb79fef03 216 mbedtls_mpi_cmp_int( E, 0 ) == 0 )
kevman 0:38ceb79fef03 217 {
kevman 0:38ceb79fef03 218 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
kevman 0:38ceb79fef03 219 }
kevman 0:38ceb79fef03 220
kevman 0:38ceb79fef03 221 mbedtls_mpi_init( &K );
kevman 0:38ceb79fef03 222 mbedtls_mpi_init( &L );
kevman 0:38ceb79fef03 223
kevman 0:38ceb79fef03 224 /* Temporarily put K := P-1 and L := Q-1 */
kevman 0:38ceb79fef03 225 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, P, 1 ) );
kevman 0:38ceb79fef03 226 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &L, Q, 1 ) );
kevman 0:38ceb79fef03 227
kevman 0:38ceb79fef03 228 /* Temporarily put D := gcd(P-1, Q-1) */
kevman 0:38ceb79fef03 229 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( D, &K, &L ) );
kevman 0:38ceb79fef03 230
kevman 0:38ceb79fef03 231 /* K := LCM(P-1, Q-1) */
kevman 0:38ceb79fef03 232 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, &K, &L ) );
kevman 0:38ceb79fef03 233 MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &K, NULL, &K, D ) );
kevman 0:38ceb79fef03 234
kevman 0:38ceb79fef03 235 /* Compute modular inverse of E in LCM(P-1, Q-1) */
kevman 0:38ceb79fef03 236 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( D, E, &K ) );
kevman 0:38ceb79fef03 237
kevman 0:38ceb79fef03 238 cleanup:
kevman 0:38ceb79fef03 239
kevman 0:38ceb79fef03 240 mbedtls_mpi_free( &K );
kevman 0:38ceb79fef03 241 mbedtls_mpi_free( &L );
kevman 0:38ceb79fef03 242
kevman 0:38ceb79fef03 243 return( ret );
kevman 0:38ceb79fef03 244 }
kevman 0:38ceb79fef03 245
kevman 0:38ceb79fef03 246 /*
kevman 0:38ceb79fef03 247 * Check that RSA CRT parameters are in accordance with core parameters.
kevman 0:38ceb79fef03 248 */
kevman 0:38ceb79fef03 249 int mbedtls_rsa_validate_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q,
kevman 0:38ceb79fef03 250 const mbedtls_mpi *D, const mbedtls_mpi *DP,
kevman 0:38ceb79fef03 251 const mbedtls_mpi *DQ, const mbedtls_mpi *QP )
kevman 0:38ceb79fef03 252 {
kevman 0:38ceb79fef03 253 int ret = 0;
kevman 0:38ceb79fef03 254
kevman 0:38ceb79fef03 255 mbedtls_mpi K, L;
kevman 0:38ceb79fef03 256 mbedtls_mpi_init( &K );
kevman 0:38ceb79fef03 257 mbedtls_mpi_init( &L );
kevman 0:38ceb79fef03 258
kevman 0:38ceb79fef03 259 /* Check that DP - D == 0 mod P - 1 */
kevman 0:38ceb79fef03 260 if( DP != NULL )
kevman 0:38ceb79fef03 261 {
kevman 0:38ceb79fef03 262 if( P == NULL )
kevman 0:38ceb79fef03 263 {
kevman 0:38ceb79fef03 264 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
kevman 0:38ceb79fef03 265 goto cleanup;
kevman 0:38ceb79fef03 266 }
kevman 0:38ceb79fef03 267
kevman 0:38ceb79fef03 268 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, P, 1 ) );
kevman 0:38ceb79fef03 269 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &L, DP, D ) );
kevman 0:38ceb79fef03 270 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &L, &L, &K ) );
kevman 0:38ceb79fef03 271
kevman 0:38ceb79fef03 272 if( mbedtls_mpi_cmp_int( &L, 0 ) != 0 )
kevman 0:38ceb79fef03 273 {
kevman 0:38ceb79fef03 274 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 275 goto cleanup;
kevman 0:38ceb79fef03 276 }
kevman 0:38ceb79fef03 277 }
kevman 0:38ceb79fef03 278
kevman 0:38ceb79fef03 279 /* Check that DQ - D == 0 mod Q - 1 */
kevman 0:38ceb79fef03 280 if( DQ != NULL )
kevman 0:38ceb79fef03 281 {
kevman 0:38ceb79fef03 282 if( Q == NULL )
kevman 0:38ceb79fef03 283 {
kevman 0:38ceb79fef03 284 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
kevman 0:38ceb79fef03 285 goto cleanup;
kevman 0:38ceb79fef03 286 }
kevman 0:38ceb79fef03 287
kevman 0:38ceb79fef03 288 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, Q, 1 ) );
kevman 0:38ceb79fef03 289 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &L, DQ, D ) );
kevman 0:38ceb79fef03 290 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &L, &L, &K ) );
kevman 0:38ceb79fef03 291
kevman 0:38ceb79fef03 292 if( mbedtls_mpi_cmp_int( &L, 0 ) != 0 )
kevman 0:38ceb79fef03 293 {
kevman 0:38ceb79fef03 294 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 295 goto cleanup;
kevman 0:38ceb79fef03 296 }
kevman 0:38ceb79fef03 297 }
kevman 0:38ceb79fef03 298
kevman 0:38ceb79fef03 299 /* Check that QP * Q - 1 == 0 mod P */
kevman 0:38ceb79fef03 300 if( QP != NULL )
kevman 0:38ceb79fef03 301 {
kevman 0:38ceb79fef03 302 if( P == NULL || Q == NULL )
kevman 0:38ceb79fef03 303 {
kevman 0:38ceb79fef03 304 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
kevman 0:38ceb79fef03 305 goto cleanup;
kevman 0:38ceb79fef03 306 }
kevman 0:38ceb79fef03 307
kevman 0:38ceb79fef03 308 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, QP, Q ) );
kevman 0:38ceb79fef03 309 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
kevman 0:38ceb79fef03 310 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, P ) );
kevman 0:38ceb79fef03 311 if( mbedtls_mpi_cmp_int( &K, 0 ) != 0 )
kevman 0:38ceb79fef03 312 {
kevman 0:38ceb79fef03 313 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 314 goto cleanup;
kevman 0:38ceb79fef03 315 }
kevman 0:38ceb79fef03 316 }
kevman 0:38ceb79fef03 317
kevman 0:38ceb79fef03 318 cleanup:
kevman 0:38ceb79fef03 319
kevman 0:38ceb79fef03 320 /* Wrap MPI error codes by RSA check failure error code */
kevman 0:38ceb79fef03 321 if( ret != 0 &&
kevman 0:38ceb79fef03 322 ret != MBEDTLS_ERR_RSA_KEY_CHECK_FAILED &&
kevman 0:38ceb79fef03 323 ret != MBEDTLS_ERR_RSA_BAD_INPUT_DATA )
kevman 0:38ceb79fef03 324 {
kevman 0:38ceb79fef03 325 ret += MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 326 }
kevman 0:38ceb79fef03 327
kevman 0:38ceb79fef03 328 mbedtls_mpi_free( &K );
kevman 0:38ceb79fef03 329 mbedtls_mpi_free( &L );
kevman 0:38ceb79fef03 330
kevman 0:38ceb79fef03 331 return( ret );
kevman 0:38ceb79fef03 332 }
kevman 0:38ceb79fef03 333
kevman 0:38ceb79fef03 334 /*
kevman 0:38ceb79fef03 335 * Check that core RSA parameters are sane.
kevman 0:38ceb79fef03 336 */
kevman 0:38ceb79fef03 337 int mbedtls_rsa_validate_params( const mbedtls_mpi *N, const mbedtls_mpi *P,
kevman 0:38ceb79fef03 338 const mbedtls_mpi *Q, const mbedtls_mpi *D,
kevman 0:38ceb79fef03 339 const mbedtls_mpi *E,
kevman 0:38ceb79fef03 340 int (*f_rng)(void *, unsigned char *, size_t),
kevman 0:38ceb79fef03 341 void *p_rng )
kevman 0:38ceb79fef03 342 {
kevman 0:38ceb79fef03 343 int ret = 0;
kevman 0:38ceb79fef03 344 mbedtls_mpi K, L;
kevman 0:38ceb79fef03 345
kevman 0:38ceb79fef03 346 mbedtls_mpi_init( &K );
kevman 0:38ceb79fef03 347 mbedtls_mpi_init( &L );
kevman 0:38ceb79fef03 348
kevman 0:38ceb79fef03 349 /*
kevman 0:38ceb79fef03 350 * Step 1: If PRNG provided, check that P and Q are prime
kevman 0:38ceb79fef03 351 */
kevman 0:38ceb79fef03 352
kevman 0:38ceb79fef03 353 #if defined(MBEDTLS_GENPRIME)
kevman 0:38ceb79fef03 354 if( f_rng != NULL && P != NULL &&
kevman 0:38ceb79fef03 355 ( ret = mbedtls_mpi_is_prime( P, f_rng, p_rng ) ) != 0 )
kevman 0:38ceb79fef03 356 {
kevman 0:38ceb79fef03 357 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 358 goto cleanup;
kevman 0:38ceb79fef03 359 }
kevman 0:38ceb79fef03 360
kevman 0:38ceb79fef03 361 if( f_rng != NULL && Q != NULL &&
kevman 0:38ceb79fef03 362 ( ret = mbedtls_mpi_is_prime( Q, f_rng, p_rng ) ) != 0 )
kevman 0:38ceb79fef03 363 {
kevman 0:38ceb79fef03 364 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 365 goto cleanup;
kevman 0:38ceb79fef03 366 }
kevman 0:38ceb79fef03 367 #else
kevman 0:38ceb79fef03 368 ((void) f_rng);
kevman 0:38ceb79fef03 369 ((void) p_rng);
kevman 0:38ceb79fef03 370 #endif /* MBEDTLS_GENPRIME */
kevman 0:38ceb79fef03 371
kevman 0:38ceb79fef03 372 /*
kevman 0:38ceb79fef03 373 * Step 2: Check that 1 < N = P * Q
kevman 0:38ceb79fef03 374 */
kevman 0:38ceb79fef03 375
kevman 0:38ceb79fef03 376 if( P != NULL && Q != NULL && N != NULL )
kevman 0:38ceb79fef03 377 {
kevman 0:38ceb79fef03 378 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, P, Q ) );
kevman 0:38ceb79fef03 379 if( mbedtls_mpi_cmp_int( N, 1 ) <= 0 ||
kevman 0:38ceb79fef03 380 mbedtls_mpi_cmp_mpi( &K, N ) != 0 )
kevman 0:38ceb79fef03 381 {
kevman 0:38ceb79fef03 382 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 383 goto cleanup;
kevman 0:38ceb79fef03 384 }
kevman 0:38ceb79fef03 385 }
kevman 0:38ceb79fef03 386
kevman 0:38ceb79fef03 387 /*
kevman 0:38ceb79fef03 388 * Step 3: Check and 1 < D, E < N if present.
kevman 0:38ceb79fef03 389 */
kevman 0:38ceb79fef03 390
kevman 0:38ceb79fef03 391 if( N != NULL && D != NULL && E != NULL )
kevman 0:38ceb79fef03 392 {
kevman 0:38ceb79fef03 393 if ( mbedtls_mpi_cmp_int( D, 1 ) <= 0 ||
kevman 0:38ceb79fef03 394 mbedtls_mpi_cmp_int( E, 1 ) <= 0 ||
kevman 0:38ceb79fef03 395 mbedtls_mpi_cmp_mpi( D, N ) >= 0 ||
kevman 0:38ceb79fef03 396 mbedtls_mpi_cmp_mpi( E, N ) >= 0 )
kevman 0:38ceb79fef03 397 {
kevman 0:38ceb79fef03 398 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 399 goto cleanup;
kevman 0:38ceb79fef03 400 }
kevman 0:38ceb79fef03 401 }
kevman 0:38ceb79fef03 402
kevman 0:38ceb79fef03 403 /*
kevman 0:38ceb79fef03 404 * Step 4: Check that D, E are inverse modulo P-1 and Q-1
kevman 0:38ceb79fef03 405 */
kevman 0:38ceb79fef03 406
kevman 0:38ceb79fef03 407 if( P != NULL && Q != NULL && D != NULL && E != NULL )
kevman 0:38ceb79fef03 408 {
kevman 0:38ceb79fef03 409 if( mbedtls_mpi_cmp_int( P, 1 ) <= 0 ||
kevman 0:38ceb79fef03 410 mbedtls_mpi_cmp_int( Q, 1 ) <= 0 )
kevman 0:38ceb79fef03 411 {
kevman 0:38ceb79fef03 412 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 413 goto cleanup;
kevman 0:38ceb79fef03 414 }
kevman 0:38ceb79fef03 415
kevman 0:38ceb79fef03 416 /* Compute DE-1 mod P-1 */
kevman 0:38ceb79fef03 417 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, D, E ) );
kevman 0:38ceb79fef03 418 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
kevman 0:38ceb79fef03 419 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &L, P, 1 ) );
kevman 0:38ceb79fef03 420 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, &L ) );
kevman 0:38ceb79fef03 421 if( mbedtls_mpi_cmp_int( &K, 0 ) != 0 )
kevman 0:38ceb79fef03 422 {
kevman 0:38ceb79fef03 423 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 424 goto cleanup;
kevman 0:38ceb79fef03 425 }
kevman 0:38ceb79fef03 426
kevman 0:38ceb79fef03 427 /* Compute DE-1 mod Q-1 */
kevman 0:38ceb79fef03 428 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, D, E ) );
kevman 0:38ceb79fef03 429 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
kevman 0:38ceb79fef03 430 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &L, Q, 1 ) );
kevman 0:38ceb79fef03 431 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, &L ) );
kevman 0:38ceb79fef03 432 if( mbedtls_mpi_cmp_int( &K, 0 ) != 0 )
kevman 0:38ceb79fef03 433 {
kevman 0:38ceb79fef03 434 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 435 goto cleanup;
kevman 0:38ceb79fef03 436 }
kevman 0:38ceb79fef03 437 }
kevman 0:38ceb79fef03 438
kevman 0:38ceb79fef03 439 cleanup:
kevman 0:38ceb79fef03 440
kevman 0:38ceb79fef03 441 mbedtls_mpi_free( &K );
kevman 0:38ceb79fef03 442 mbedtls_mpi_free( &L );
kevman 0:38ceb79fef03 443
kevman 0:38ceb79fef03 444 /* Wrap MPI error codes by RSA check failure error code */
kevman 0:38ceb79fef03 445 if( ret != 0 && ret != MBEDTLS_ERR_RSA_KEY_CHECK_FAILED )
kevman 0:38ceb79fef03 446 {
kevman 0:38ceb79fef03 447 ret += MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
kevman 0:38ceb79fef03 448 }
kevman 0:38ceb79fef03 449
kevman 0:38ceb79fef03 450 return( ret );
kevman 0:38ceb79fef03 451 }
kevman 0:38ceb79fef03 452
kevman 0:38ceb79fef03 453 int mbedtls_rsa_deduce_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q,
kevman 0:38ceb79fef03 454 const mbedtls_mpi *D, mbedtls_mpi *DP,
kevman 0:38ceb79fef03 455 mbedtls_mpi *DQ, mbedtls_mpi *QP )
kevman 0:38ceb79fef03 456 {
kevman 0:38ceb79fef03 457 int ret = 0;
kevman 0:38ceb79fef03 458 mbedtls_mpi K;
kevman 0:38ceb79fef03 459 mbedtls_mpi_init( &K );
kevman 0:38ceb79fef03 460
kevman 0:38ceb79fef03 461 /* DP = D mod P-1 */
kevman 0:38ceb79fef03 462 if( DP != NULL )
kevman 0:38ceb79fef03 463 {
kevman 0:38ceb79fef03 464 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, P, 1 ) );
kevman 0:38ceb79fef03 465 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( DP, D, &K ) );
kevman 0:38ceb79fef03 466 }
kevman 0:38ceb79fef03 467
kevman 0:38ceb79fef03 468 /* DQ = D mod Q-1 */
kevman 0:38ceb79fef03 469 if( DQ != NULL )
kevman 0:38ceb79fef03 470 {
kevman 0:38ceb79fef03 471 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, Q, 1 ) );
kevman 0:38ceb79fef03 472 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( DQ, D, &K ) );
kevman 0:38ceb79fef03 473 }
kevman 0:38ceb79fef03 474
kevman 0:38ceb79fef03 475 /* QP = Q^{-1} mod P */
kevman 0:38ceb79fef03 476 if( QP != NULL )
kevman 0:38ceb79fef03 477 {
kevman 0:38ceb79fef03 478 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( QP, Q, P ) );
kevman 0:38ceb79fef03 479 }
kevman 0:38ceb79fef03 480
kevman 0:38ceb79fef03 481 cleanup:
kevman 0:38ceb79fef03 482 mbedtls_mpi_free( &K );
kevman 0:38ceb79fef03 483
kevman 0:38ceb79fef03 484 return( ret );
kevman 0:38ceb79fef03 485 }
kevman 0:38ceb79fef03 486
kevman 0:38ceb79fef03 487 #endif /* MBEDTLS_RSA_C */