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mbed-os/features/mbedtls/src/rsa_internal.c@0:9b3d4731edbb, 2018-06-21 (annotated)

Committer:
WFKnight
Date:
Thu Jun 21 13:51:43 2018 +0000
Revision:
0:9b3d4731edbb
UART, RTOS, LED

Who changed what in which revision?

UserRevisionLine numberNew contents of line
WFKnight 0:9b3d4731edbb 1 /*
WFKnight 0:9b3d4731edbb 2 * Helper functions for the RSA module
WFKnight 0:9b3d4731edbb 3 *
WFKnight 0:9b3d4731edbb 4 * Copyright (C) 2006-2017, ARM Limited, All Rights Reserved
WFKnight 0:9b3d4731edbb 5 * SPDX-License-Identifier: Apache-2.0
WFKnight 0:9b3d4731edbb 6 *
WFKnight 0:9b3d4731edbb 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may
WFKnight 0:9b3d4731edbb 8 * not use this file except in compliance with the License.
WFKnight 0:9b3d4731edbb 9 * You may obtain a copy of the License at
WFKnight 0:9b3d4731edbb 10 *
WFKnight 0:9b3d4731edbb 11 * http://www.apache.org/licenses/LICENSE-2.0
WFKnight 0:9b3d4731edbb 12 *
WFKnight 0:9b3d4731edbb 13 * Unless required by applicable law or agreed to in writing, software
WFKnight 0:9b3d4731edbb 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WFKnight 0:9b3d4731edbb 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
WFKnight 0:9b3d4731edbb 16 * See the License for the specific language governing permissions and
WFKnight 0:9b3d4731edbb 17 * limitations under the License.
WFKnight 0:9b3d4731edbb 18 *
WFKnight 0:9b3d4731edbb 19 * This file is part of mbed TLS (https://tls.mbed.org)
WFKnight 0:9b3d4731edbb 20 *
WFKnight 0:9b3d4731edbb 21 */
WFKnight 0:9b3d4731edbb 22
WFKnight 0:9b3d4731edbb 23 #if !defined(MBEDTLS_CONFIG_FILE)
WFKnight 0:9b3d4731edbb 24 #include "mbedtls/config.h"
WFKnight 0:9b3d4731edbb 25 #else
WFKnight 0:9b3d4731edbb 26 #include MBEDTLS_CONFIG_FILE
WFKnight 0:9b3d4731edbb 27 #endif
WFKnight 0:9b3d4731edbb 28
WFKnight 0:9b3d4731edbb 29 #if defined(MBEDTLS_RSA_C)
WFKnight 0:9b3d4731edbb 30
WFKnight 0:9b3d4731edbb 31 #include "mbedtls/rsa.h"
WFKnight 0:9b3d4731edbb 32 #include "mbedtls/bignum.h"
WFKnight 0:9b3d4731edbb 33 #include "mbedtls/rsa_internal.h"
WFKnight 0:9b3d4731edbb 34
WFKnight 0:9b3d4731edbb 35 /*
WFKnight 0:9b3d4731edbb 36 * Compute RSA prime factors from public and private exponents
WFKnight 0:9b3d4731edbb 37 *
WFKnight 0:9b3d4731edbb 38 * Summary of algorithm:
WFKnight 0:9b3d4731edbb 39 * Setting F := lcm(P-1,Q-1), the idea is as follows:
WFKnight 0:9b3d4731edbb 40 *
WFKnight 0:9b3d4731edbb 41 * (a) For any 1 <= X < N with gcd(X,N)=1, we have X^F = 1 modulo N, so X^(F/2)
WFKnight 0:9b3d4731edbb 42 * is a square root of 1 in Z/NZ. Since Z/NZ ~= Z/PZ x Z/QZ by CRT and the
WFKnight 0:9b3d4731edbb 43 * square roots of 1 in Z/PZ and Z/QZ are +1 and -1, this leaves the four
WFKnight 0:9b3d4731edbb 44 * possibilities X^(F/2) = (+-1, +-1). If it happens that X^(F/2) = (-1,+1)
WFKnight 0:9b3d4731edbb 45 * or (+1,-1), then gcd(X^(F/2) + 1, N) will be equal to one of the prime
WFKnight 0:9b3d4731edbb 46 * factors of N.
WFKnight 0:9b3d4731edbb 47 *
WFKnight 0:9b3d4731edbb 48 * (b) If we don't know F/2 but (F/2) * K for some odd (!) K, then the same
WFKnight 0:9b3d4731edbb 49 * construction still applies since (-)^K is the identity on the set of
WFKnight 0:9b3d4731edbb 50 * roots of 1 in Z/NZ.
WFKnight 0:9b3d4731edbb 51 *
WFKnight 0:9b3d4731edbb 52 * The public and private key primitives (-)^E and (-)^D are mutually inverse
WFKnight 0:9b3d4731edbb 53 * bijections on Z/NZ if and only if (-)^(DE) is the identity on Z/NZ, i.e.
WFKnight 0:9b3d4731edbb 54 * if and only if DE - 1 is a multiple of F, say DE - 1 = F * L.
WFKnight 0:9b3d4731edbb 55 * Splitting L = 2^t * K with K odd, we have
WFKnight 0:9b3d4731edbb 56 *
WFKnight 0:9b3d4731edbb 57 * DE - 1 = FL = (F/2) * (2^(t+1)) * K,
WFKnight 0:9b3d4731edbb 58 *
WFKnight 0:9b3d4731edbb 59 * so (F / 2) * K is among the numbers
WFKnight 0:9b3d4731edbb 60 *
WFKnight 0:9b3d4731edbb 61 * (DE - 1) >> 1, (DE - 1) >> 2, ..., (DE - 1) >> ord
WFKnight 0:9b3d4731edbb 62 *
WFKnight 0:9b3d4731edbb 63 * where ord is the order of 2 in (DE - 1).
WFKnight 0:9b3d4731edbb 64 * We can therefore iterate through these numbers apply the construction
WFKnight 0:9b3d4731edbb 65 * of (a) and (b) above to attempt to factor N.
WFKnight 0:9b3d4731edbb 66 *
WFKnight 0:9b3d4731edbb 67 */
WFKnight 0:9b3d4731edbb 68 int mbedtls_rsa_deduce_primes( mbedtls_mpi const *N,
WFKnight 0:9b3d4731edbb 69 mbedtls_mpi const *E, mbedtls_mpi const *D,
WFKnight 0:9b3d4731edbb 70 mbedtls_mpi *P, mbedtls_mpi *Q )
WFKnight 0:9b3d4731edbb 71 {
WFKnight 0:9b3d4731edbb 72 int ret = 0;
WFKnight 0:9b3d4731edbb 73
WFKnight 0:9b3d4731edbb 74 uint16_t attempt; /* Number of current attempt */
WFKnight 0:9b3d4731edbb 75 uint16_t iter; /* Number of squares computed in the current attempt */
WFKnight 0:9b3d4731edbb 76
WFKnight 0:9b3d4731edbb 77 uint16_t order; /* Order of 2 in DE - 1 */
WFKnight 0:9b3d4731edbb 78
WFKnight 0:9b3d4731edbb 79 mbedtls_mpi T; /* Holds largest odd divisor of DE - 1 */
WFKnight 0:9b3d4731edbb 80 mbedtls_mpi K; /* Temporary holding the current candidate */
WFKnight 0:9b3d4731edbb 81
WFKnight 0:9b3d4731edbb 82 const unsigned char primes[] = { 2,
WFKnight 0:9b3d4731edbb 83 3, 5, 7, 11, 13, 17, 19, 23,
WFKnight 0:9b3d4731edbb 84 29, 31, 37, 41, 43, 47, 53, 59,
WFKnight 0:9b3d4731edbb 85 61, 67, 71, 73, 79, 83, 89, 97,
WFKnight 0:9b3d4731edbb 86 101, 103, 107, 109, 113, 127, 131, 137,
WFKnight 0:9b3d4731edbb 87 139, 149, 151, 157, 163, 167, 173, 179,
WFKnight 0:9b3d4731edbb 88 181, 191, 193, 197, 199, 211, 223, 227,
WFKnight 0:9b3d4731edbb 89 229, 233, 239, 241, 251
WFKnight 0:9b3d4731edbb 90 };
WFKnight 0:9b3d4731edbb 91
WFKnight 0:9b3d4731edbb 92 const size_t num_primes = sizeof( primes ) / sizeof( *primes );
WFKnight 0:9b3d4731edbb 93
WFKnight 0:9b3d4731edbb 94 if( P == NULL || Q == NULL || P->p != NULL || Q->p != NULL )
WFKnight 0:9b3d4731edbb 95 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
WFKnight 0:9b3d4731edbb 96
WFKnight 0:9b3d4731edbb 97 if( mbedtls_mpi_cmp_int( N, 0 ) <= 0 ||
WFKnight 0:9b3d4731edbb 98 mbedtls_mpi_cmp_int( D, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 99 mbedtls_mpi_cmp_mpi( D, N ) >= 0 ||
WFKnight 0:9b3d4731edbb 100 mbedtls_mpi_cmp_int( E, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 101 mbedtls_mpi_cmp_mpi( E, N ) >= 0 )
WFKnight 0:9b3d4731edbb 102 {
WFKnight 0:9b3d4731edbb 103 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
WFKnight 0:9b3d4731edbb 104 }
WFKnight 0:9b3d4731edbb 105
WFKnight 0:9b3d4731edbb 106 /*
WFKnight 0:9b3d4731edbb 107 * Initializations and temporary changes
WFKnight 0:9b3d4731edbb 108 */
WFKnight 0:9b3d4731edbb 109
WFKnight 0:9b3d4731edbb 110 mbedtls_mpi_init( &K );
WFKnight 0:9b3d4731edbb 111 mbedtls_mpi_init( &T );
WFKnight 0:9b3d4731edbb 112
WFKnight 0:9b3d4731edbb 113 /* T := DE - 1 */
WFKnight 0:9b3d4731edbb 114 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, D, E ) );
WFKnight 0:9b3d4731edbb 115 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &T, &T, 1 ) );
WFKnight 0:9b3d4731edbb 116
WFKnight 0:9b3d4731edbb 117 if( ( order = (uint16_t) mbedtls_mpi_lsb( &T ) ) == 0 )
WFKnight 0:9b3d4731edbb 118 {
WFKnight 0:9b3d4731edbb 119 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
WFKnight 0:9b3d4731edbb 120 goto cleanup;
WFKnight 0:9b3d4731edbb 121 }
WFKnight 0:9b3d4731edbb 122
WFKnight 0:9b3d4731edbb 123 /* After this operation, T holds the largest odd divisor of DE - 1. */
WFKnight 0:9b3d4731edbb 124 MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &T, order ) );
WFKnight 0:9b3d4731edbb 125
WFKnight 0:9b3d4731edbb 126 /*
WFKnight 0:9b3d4731edbb 127 * Actual work
WFKnight 0:9b3d4731edbb 128 */
WFKnight 0:9b3d4731edbb 129
WFKnight 0:9b3d4731edbb 130 /* Skip trying 2 if N == 1 mod 8 */
WFKnight 0:9b3d4731edbb 131 attempt = 0;
WFKnight 0:9b3d4731edbb 132 if( N->p[0] % 8 == 1 )
WFKnight 0:9b3d4731edbb 133 attempt = 1;
WFKnight 0:9b3d4731edbb 134
WFKnight 0:9b3d4731edbb 135 for( ; attempt < num_primes; ++attempt )
WFKnight 0:9b3d4731edbb 136 {
WFKnight 0:9b3d4731edbb 137 mbedtls_mpi_lset( &K, primes[attempt] );
WFKnight 0:9b3d4731edbb 138
WFKnight 0:9b3d4731edbb 139 /* Check if gcd(K,N) = 1 */
WFKnight 0:9b3d4731edbb 140 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( P, &K, N ) );
WFKnight 0:9b3d4731edbb 141 if( mbedtls_mpi_cmp_int( P, 1 ) != 0 )
WFKnight 0:9b3d4731edbb 142 continue;
WFKnight 0:9b3d4731edbb 143
WFKnight 0:9b3d4731edbb 144 /* Go through K^T + 1, K^(2T) + 1, K^(4T) + 1, ...
WFKnight 0:9b3d4731edbb 145 * and check whether they have nontrivial GCD with N. */
WFKnight 0:9b3d4731edbb 146 MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &K, &K, &T, N,
WFKnight 0:9b3d4731edbb 147 Q /* temporarily use Q for storing Montgomery
WFKnight 0:9b3d4731edbb 148 * multiplication helper values */ ) );
WFKnight 0:9b3d4731edbb 149
WFKnight 0:9b3d4731edbb 150 for( iter = 1; iter <= order; ++iter )
WFKnight 0:9b3d4731edbb 151 {
WFKnight 0:9b3d4731edbb 152 /* If we reach 1 prematurely, there's no point
WFKnight 0:9b3d4731edbb 153 * in continuing to square K */
WFKnight 0:9b3d4731edbb 154 if( mbedtls_mpi_cmp_int( &K, 1 ) == 0 )
WFKnight 0:9b3d4731edbb 155 break;
WFKnight 0:9b3d4731edbb 156
WFKnight 0:9b3d4731edbb 157 MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &K, &K, 1 ) );
WFKnight 0:9b3d4731edbb 158 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( P, &K, N ) );
WFKnight 0:9b3d4731edbb 159
WFKnight 0:9b3d4731edbb 160 if( mbedtls_mpi_cmp_int( P, 1 ) == 1 &&
WFKnight 0:9b3d4731edbb 161 mbedtls_mpi_cmp_mpi( P, N ) == -1 )
WFKnight 0:9b3d4731edbb 162 {
WFKnight 0:9b3d4731edbb 163 /*
WFKnight 0:9b3d4731edbb 164 * Have found a nontrivial divisor P of N.
WFKnight 0:9b3d4731edbb 165 * Set Q := N / P.
WFKnight 0:9b3d4731edbb 166 */
WFKnight 0:9b3d4731edbb 167
WFKnight 0:9b3d4731edbb 168 MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( Q, NULL, N, P ) );
WFKnight 0:9b3d4731edbb 169 goto cleanup;
WFKnight 0:9b3d4731edbb 170 }
WFKnight 0:9b3d4731edbb 171
WFKnight 0:9b3d4731edbb 172 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
WFKnight 0:9b3d4731edbb 173 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, &K, &K ) );
WFKnight 0:9b3d4731edbb 174 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, N ) );
WFKnight 0:9b3d4731edbb 175 }
WFKnight 0:9b3d4731edbb 176
WFKnight 0:9b3d4731edbb 177 /*
WFKnight 0:9b3d4731edbb 178 * If we get here, then either we prematurely aborted the loop because
WFKnight 0:9b3d4731edbb 179 * we reached 1, or K holds primes[attempt]^(DE - 1) mod N, which must
WFKnight 0:9b3d4731edbb 180 * be 1 if D,E,N were consistent.
WFKnight 0:9b3d4731edbb 181 * Check if that's the case and abort if not, to avoid very long,
WFKnight 0:9b3d4731edbb 182 * yet eventually failing, computations if N,D,E were not sane.
WFKnight 0:9b3d4731edbb 183 */
WFKnight 0:9b3d4731edbb 184 if( mbedtls_mpi_cmp_int( &K, 1 ) != 0 )
WFKnight 0:9b3d4731edbb 185 {
WFKnight 0:9b3d4731edbb 186 break;
WFKnight 0:9b3d4731edbb 187 }
WFKnight 0:9b3d4731edbb 188 }
WFKnight 0:9b3d4731edbb 189
WFKnight 0:9b3d4731edbb 190 ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
WFKnight 0:9b3d4731edbb 191
WFKnight 0:9b3d4731edbb 192 cleanup:
WFKnight 0:9b3d4731edbb 193
WFKnight 0:9b3d4731edbb 194 mbedtls_mpi_free( &K );
WFKnight 0:9b3d4731edbb 195 mbedtls_mpi_free( &T );
WFKnight 0:9b3d4731edbb 196 return( ret );
WFKnight 0:9b3d4731edbb 197 }
WFKnight 0:9b3d4731edbb 198
WFKnight 0:9b3d4731edbb 199 /*
WFKnight 0:9b3d4731edbb 200 * Given P, Q and the public exponent E, deduce D.
WFKnight 0:9b3d4731edbb 201 * This is essentially a modular inversion.
WFKnight 0:9b3d4731edbb 202 */
WFKnight 0:9b3d4731edbb 203 int mbedtls_rsa_deduce_private_exponent( mbedtls_mpi const *P,
WFKnight 0:9b3d4731edbb 204 mbedtls_mpi const *Q,
WFKnight 0:9b3d4731edbb 205 mbedtls_mpi const *E,
WFKnight 0:9b3d4731edbb 206 mbedtls_mpi *D )
WFKnight 0:9b3d4731edbb 207 {
WFKnight 0:9b3d4731edbb 208 int ret = 0;
WFKnight 0:9b3d4731edbb 209 mbedtls_mpi K, L;
WFKnight 0:9b3d4731edbb 210
WFKnight 0:9b3d4731edbb 211 if( D == NULL || mbedtls_mpi_cmp_int( D, 0 ) != 0 )
WFKnight 0:9b3d4731edbb 212 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
WFKnight 0:9b3d4731edbb 213
WFKnight 0:9b3d4731edbb 214 if( mbedtls_mpi_cmp_int( P, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 215 mbedtls_mpi_cmp_int( Q, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 216 mbedtls_mpi_cmp_int( E, 0 ) == 0 )
WFKnight 0:9b3d4731edbb 217 {
WFKnight 0:9b3d4731edbb 218 return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
WFKnight 0:9b3d4731edbb 219 }
WFKnight 0:9b3d4731edbb 220
WFKnight 0:9b3d4731edbb 221 mbedtls_mpi_init( &K );
WFKnight 0:9b3d4731edbb 222 mbedtls_mpi_init( &L );
WFKnight 0:9b3d4731edbb 223
WFKnight 0:9b3d4731edbb 224 /* Temporarily put K := P-1 and L := Q-1 */
WFKnight 0:9b3d4731edbb 225 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, P, 1 ) );
WFKnight 0:9b3d4731edbb 226 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &L, Q, 1 ) );
WFKnight 0:9b3d4731edbb 227
WFKnight 0:9b3d4731edbb 228 /* Temporarily put D := gcd(P-1, Q-1) */
WFKnight 0:9b3d4731edbb 229 MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( D, &K, &L ) );
WFKnight 0:9b3d4731edbb 230
WFKnight 0:9b3d4731edbb 231 /* K := LCM(P-1, Q-1) */
WFKnight 0:9b3d4731edbb 232 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, &K, &L ) );
WFKnight 0:9b3d4731edbb 233 MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &K, NULL, &K, D ) );
WFKnight 0:9b3d4731edbb 234
WFKnight 0:9b3d4731edbb 235 /* Compute modular inverse of E in LCM(P-1, Q-1) */
WFKnight 0:9b3d4731edbb 236 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( D, E, &K ) );
WFKnight 0:9b3d4731edbb 237
WFKnight 0:9b3d4731edbb 238 cleanup:
WFKnight 0:9b3d4731edbb 239
WFKnight 0:9b3d4731edbb 240 mbedtls_mpi_free( &K );
WFKnight 0:9b3d4731edbb 241 mbedtls_mpi_free( &L );
WFKnight 0:9b3d4731edbb 242
WFKnight 0:9b3d4731edbb 243 return( ret );
WFKnight 0:9b3d4731edbb 244 }
WFKnight 0:9b3d4731edbb 245
WFKnight 0:9b3d4731edbb 246 /*
WFKnight 0:9b3d4731edbb 247 * Check that RSA CRT parameters are in accordance with core parameters.
WFKnight 0:9b3d4731edbb 248 */
WFKnight 0:9b3d4731edbb 249 int mbedtls_rsa_validate_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q,
WFKnight 0:9b3d4731edbb 250 const mbedtls_mpi *D, const mbedtls_mpi *DP,
WFKnight 0:9b3d4731edbb 251 const mbedtls_mpi *DQ, const mbedtls_mpi *QP )
WFKnight 0:9b3d4731edbb 252 {
WFKnight 0:9b3d4731edbb 253 int ret = 0;
WFKnight 0:9b3d4731edbb 254
WFKnight 0:9b3d4731edbb 255 mbedtls_mpi K, L;
WFKnight 0:9b3d4731edbb 256 mbedtls_mpi_init( &K );
WFKnight 0:9b3d4731edbb 257 mbedtls_mpi_init( &L );
WFKnight 0:9b3d4731edbb 258
WFKnight 0:9b3d4731edbb 259 /* Check that DP - D == 0 mod P - 1 */
WFKnight 0:9b3d4731edbb 260 if( DP != NULL )
WFKnight 0:9b3d4731edbb 261 {
WFKnight 0:9b3d4731edbb 262 if( P == NULL )
WFKnight 0:9b3d4731edbb 263 {
WFKnight 0:9b3d4731edbb 264 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
WFKnight 0:9b3d4731edbb 265 goto cleanup;
WFKnight 0:9b3d4731edbb 266 }
WFKnight 0:9b3d4731edbb 267
WFKnight 0:9b3d4731edbb 268 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, P, 1 ) );
WFKnight 0:9b3d4731edbb 269 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &L, DP, D ) );
WFKnight 0:9b3d4731edbb 270 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &L, &L, &K ) );
WFKnight 0:9b3d4731edbb 271
WFKnight 0:9b3d4731edbb 272 if( mbedtls_mpi_cmp_int( &L, 0 ) != 0 )
WFKnight 0:9b3d4731edbb 273 {
WFKnight 0:9b3d4731edbb 274 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 275 goto cleanup;
WFKnight 0:9b3d4731edbb 276 }
WFKnight 0:9b3d4731edbb 277 }
WFKnight 0:9b3d4731edbb 278
WFKnight 0:9b3d4731edbb 279 /* Check that DQ - D == 0 mod Q - 1 */
WFKnight 0:9b3d4731edbb 280 if( DQ != NULL )
WFKnight 0:9b3d4731edbb 281 {
WFKnight 0:9b3d4731edbb 282 if( Q == NULL )
WFKnight 0:9b3d4731edbb 283 {
WFKnight 0:9b3d4731edbb 284 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
WFKnight 0:9b3d4731edbb 285 goto cleanup;
WFKnight 0:9b3d4731edbb 286 }
WFKnight 0:9b3d4731edbb 287
WFKnight 0:9b3d4731edbb 288 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, Q, 1 ) );
WFKnight 0:9b3d4731edbb 289 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &L, DQ, D ) );
WFKnight 0:9b3d4731edbb 290 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &L, &L, &K ) );
WFKnight 0:9b3d4731edbb 291
WFKnight 0:9b3d4731edbb 292 if( mbedtls_mpi_cmp_int( &L, 0 ) != 0 )
WFKnight 0:9b3d4731edbb 293 {
WFKnight 0:9b3d4731edbb 294 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 295 goto cleanup;
WFKnight 0:9b3d4731edbb 296 }
WFKnight 0:9b3d4731edbb 297 }
WFKnight 0:9b3d4731edbb 298
WFKnight 0:9b3d4731edbb 299 /* Check that QP * Q - 1 == 0 mod P */
WFKnight 0:9b3d4731edbb 300 if( QP != NULL )
WFKnight 0:9b3d4731edbb 301 {
WFKnight 0:9b3d4731edbb 302 if( P == NULL || Q == NULL )
WFKnight 0:9b3d4731edbb 303 {
WFKnight 0:9b3d4731edbb 304 ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
WFKnight 0:9b3d4731edbb 305 goto cleanup;
WFKnight 0:9b3d4731edbb 306 }
WFKnight 0:9b3d4731edbb 307
WFKnight 0:9b3d4731edbb 308 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, QP, Q ) );
WFKnight 0:9b3d4731edbb 309 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
WFKnight 0:9b3d4731edbb 310 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, P ) );
WFKnight 0:9b3d4731edbb 311 if( mbedtls_mpi_cmp_int( &K, 0 ) != 0 )
WFKnight 0:9b3d4731edbb 312 {
WFKnight 0:9b3d4731edbb 313 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 314 goto cleanup;
WFKnight 0:9b3d4731edbb 315 }
WFKnight 0:9b3d4731edbb 316 }
WFKnight 0:9b3d4731edbb 317
WFKnight 0:9b3d4731edbb 318 cleanup:
WFKnight 0:9b3d4731edbb 319
WFKnight 0:9b3d4731edbb 320 /* Wrap MPI error codes by RSA check failure error code */
WFKnight 0:9b3d4731edbb 321 if( ret != 0 &&
WFKnight 0:9b3d4731edbb 322 ret != MBEDTLS_ERR_RSA_KEY_CHECK_FAILED &&
WFKnight 0:9b3d4731edbb 323 ret != MBEDTLS_ERR_RSA_BAD_INPUT_DATA )
WFKnight 0:9b3d4731edbb 324 {
WFKnight 0:9b3d4731edbb 325 ret += MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 326 }
WFKnight 0:9b3d4731edbb 327
WFKnight 0:9b3d4731edbb 328 mbedtls_mpi_free( &K );
WFKnight 0:9b3d4731edbb 329 mbedtls_mpi_free( &L );
WFKnight 0:9b3d4731edbb 330
WFKnight 0:9b3d4731edbb 331 return( ret );
WFKnight 0:9b3d4731edbb 332 }
WFKnight 0:9b3d4731edbb 333
WFKnight 0:9b3d4731edbb 334 /*
WFKnight 0:9b3d4731edbb 335 * Check that core RSA parameters are sane.
WFKnight 0:9b3d4731edbb 336 */
WFKnight 0:9b3d4731edbb 337 int mbedtls_rsa_validate_params( const mbedtls_mpi *N, const mbedtls_mpi *P,
WFKnight 0:9b3d4731edbb 338 const mbedtls_mpi *Q, const mbedtls_mpi *D,
WFKnight 0:9b3d4731edbb 339 const mbedtls_mpi *E,
WFKnight 0:9b3d4731edbb 340 int (*f_rng)(void *, unsigned char *, size_t),
WFKnight 0:9b3d4731edbb 341 void *p_rng )
WFKnight 0:9b3d4731edbb 342 {
WFKnight 0:9b3d4731edbb 343 int ret = 0;
WFKnight 0:9b3d4731edbb 344 mbedtls_mpi K, L;
WFKnight 0:9b3d4731edbb 345
WFKnight 0:9b3d4731edbb 346 mbedtls_mpi_init( &K );
WFKnight 0:9b3d4731edbb 347 mbedtls_mpi_init( &L );
WFKnight 0:9b3d4731edbb 348
WFKnight 0:9b3d4731edbb 349 /*
WFKnight 0:9b3d4731edbb 350 * Step 1: If PRNG provided, check that P and Q are prime
WFKnight 0:9b3d4731edbb 351 */
WFKnight 0:9b3d4731edbb 352
WFKnight 0:9b3d4731edbb 353 #if defined(MBEDTLS_GENPRIME)
WFKnight 0:9b3d4731edbb 354 if( f_rng != NULL && P != NULL &&
WFKnight 0:9b3d4731edbb 355 ( ret = mbedtls_mpi_is_prime( P, f_rng, p_rng ) ) != 0 )
WFKnight 0:9b3d4731edbb 356 {
WFKnight 0:9b3d4731edbb 357 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 358 goto cleanup;
WFKnight 0:9b3d4731edbb 359 }
WFKnight 0:9b3d4731edbb 360
WFKnight 0:9b3d4731edbb 361 if( f_rng != NULL && Q != NULL &&
WFKnight 0:9b3d4731edbb 362 ( ret = mbedtls_mpi_is_prime( Q, f_rng, p_rng ) ) != 0 )
WFKnight 0:9b3d4731edbb 363 {
WFKnight 0:9b3d4731edbb 364 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 365 goto cleanup;
WFKnight 0:9b3d4731edbb 366 }
WFKnight 0:9b3d4731edbb 367 #else
WFKnight 0:9b3d4731edbb 368 ((void) f_rng);
WFKnight 0:9b3d4731edbb 369 ((void) p_rng);
WFKnight 0:9b3d4731edbb 370 #endif /* MBEDTLS_GENPRIME */
WFKnight 0:9b3d4731edbb 371
WFKnight 0:9b3d4731edbb 372 /*
WFKnight 0:9b3d4731edbb 373 * Step 2: Check that 1 < N = P * Q
WFKnight 0:9b3d4731edbb 374 */
WFKnight 0:9b3d4731edbb 375
WFKnight 0:9b3d4731edbb 376 if( P != NULL && Q != NULL && N != NULL )
WFKnight 0:9b3d4731edbb 377 {
WFKnight 0:9b3d4731edbb 378 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, P, Q ) );
WFKnight 0:9b3d4731edbb 379 if( mbedtls_mpi_cmp_int( N, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 380 mbedtls_mpi_cmp_mpi( &K, N ) != 0 )
WFKnight 0:9b3d4731edbb 381 {
WFKnight 0:9b3d4731edbb 382 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 383 goto cleanup;
WFKnight 0:9b3d4731edbb 384 }
WFKnight 0:9b3d4731edbb 385 }
WFKnight 0:9b3d4731edbb 386
WFKnight 0:9b3d4731edbb 387 /*
WFKnight 0:9b3d4731edbb 388 * Step 3: Check and 1 < D, E < N if present.
WFKnight 0:9b3d4731edbb 389 */
WFKnight 0:9b3d4731edbb 390
WFKnight 0:9b3d4731edbb 391 if( N != NULL && D != NULL && E != NULL )
WFKnight 0:9b3d4731edbb 392 {
WFKnight 0:9b3d4731edbb 393 if ( mbedtls_mpi_cmp_int( D, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 394 mbedtls_mpi_cmp_int( E, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 395 mbedtls_mpi_cmp_mpi( D, N ) >= 0 ||
WFKnight 0:9b3d4731edbb 396 mbedtls_mpi_cmp_mpi( E, N ) >= 0 )
WFKnight 0:9b3d4731edbb 397 {
WFKnight 0:9b3d4731edbb 398 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 399 goto cleanup;
WFKnight 0:9b3d4731edbb 400 }
WFKnight 0:9b3d4731edbb 401 }
WFKnight 0:9b3d4731edbb 402
WFKnight 0:9b3d4731edbb 403 /*
WFKnight 0:9b3d4731edbb 404 * Step 4: Check that D, E are inverse modulo P-1 and Q-1
WFKnight 0:9b3d4731edbb 405 */
WFKnight 0:9b3d4731edbb 406
WFKnight 0:9b3d4731edbb 407 if( P != NULL && Q != NULL && D != NULL && E != NULL )
WFKnight 0:9b3d4731edbb 408 {
WFKnight 0:9b3d4731edbb 409 if( mbedtls_mpi_cmp_int( P, 1 ) <= 0 ||
WFKnight 0:9b3d4731edbb 410 mbedtls_mpi_cmp_int( Q, 1 ) <= 0 )
WFKnight 0:9b3d4731edbb 411 {
WFKnight 0:9b3d4731edbb 412 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 413 goto cleanup;
WFKnight 0:9b3d4731edbb 414 }
WFKnight 0:9b3d4731edbb 415
WFKnight 0:9b3d4731edbb 416 /* Compute DE-1 mod P-1 */
WFKnight 0:9b3d4731edbb 417 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, D, E ) );
WFKnight 0:9b3d4731edbb 418 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
WFKnight 0:9b3d4731edbb 419 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &L, P, 1 ) );
WFKnight 0:9b3d4731edbb 420 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, &L ) );
WFKnight 0:9b3d4731edbb 421 if( mbedtls_mpi_cmp_int( &K, 0 ) != 0 )
WFKnight 0:9b3d4731edbb 422 {
WFKnight 0:9b3d4731edbb 423 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 424 goto cleanup;
WFKnight 0:9b3d4731edbb 425 }
WFKnight 0:9b3d4731edbb 426
WFKnight 0:9b3d4731edbb 427 /* Compute DE-1 mod Q-1 */
WFKnight 0:9b3d4731edbb 428 MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &K, D, E ) );
WFKnight 0:9b3d4731edbb 429 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, &K, 1 ) );
WFKnight 0:9b3d4731edbb 430 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &L, Q, 1 ) );
WFKnight 0:9b3d4731edbb 431 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &K, &K, &L ) );
WFKnight 0:9b3d4731edbb 432 if( mbedtls_mpi_cmp_int( &K, 0 ) != 0 )
WFKnight 0:9b3d4731edbb 433 {
WFKnight 0:9b3d4731edbb 434 ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 435 goto cleanup;
WFKnight 0:9b3d4731edbb 436 }
WFKnight 0:9b3d4731edbb 437 }
WFKnight 0:9b3d4731edbb 438
WFKnight 0:9b3d4731edbb 439 cleanup:
WFKnight 0:9b3d4731edbb 440
WFKnight 0:9b3d4731edbb 441 mbedtls_mpi_free( &K );
WFKnight 0:9b3d4731edbb 442 mbedtls_mpi_free( &L );
WFKnight 0:9b3d4731edbb 443
WFKnight 0:9b3d4731edbb 444 /* Wrap MPI error codes by RSA check failure error code */
WFKnight 0:9b3d4731edbb 445 if( ret != 0 && ret != MBEDTLS_ERR_RSA_KEY_CHECK_FAILED )
WFKnight 0:9b3d4731edbb 446 {
WFKnight 0:9b3d4731edbb 447 ret += MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
WFKnight 0:9b3d4731edbb 448 }
WFKnight 0:9b3d4731edbb 449
WFKnight 0:9b3d4731edbb 450 return( ret );
WFKnight 0:9b3d4731edbb 451 }
WFKnight 0:9b3d4731edbb 452
WFKnight 0:9b3d4731edbb 453 int mbedtls_rsa_deduce_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q,
WFKnight 0:9b3d4731edbb 454 const mbedtls_mpi *D, mbedtls_mpi *DP,
WFKnight 0:9b3d4731edbb 455 mbedtls_mpi *DQ, mbedtls_mpi *QP )
WFKnight 0:9b3d4731edbb 456 {
WFKnight 0:9b3d4731edbb 457 int ret = 0;
WFKnight 0:9b3d4731edbb 458 mbedtls_mpi K;
WFKnight 0:9b3d4731edbb 459 mbedtls_mpi_init( &K );
WFKnight 0:9b3d4731edbb 460
WFKnight 0:9b3d4731edbb 461 /* DP = D mod P-1 */
WFKnight 0:9b3d4731edbb 462 if( DP != NULL )
WFKnight 0:9b3d4731edbb 463 {
WFKnight 0:9b3d4731edbb 464 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, P, 1 ) );
WFKnight 0:9b3d4731edbb 465 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( DP, D, &K ) );
WFKnight 0:9b3d4731edbb 466 }
WFKnight 0:9b3d4731edbb 467
WFKnight 0:9b3d4731edbb 468 /* DQ = D mod Q-1 */
WFKnight 0:9b3d4731edbb 469 if( DQ != NULL )
WFKnight 0:9b3d4731edbb 470 {
WFKnight 0:9b3d4731edbb 471 MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &K, Q, 1 ) );
WFKnight 0:9b3d4731edbb 472 MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( DQ, D, &K ) );
WFKnight 0:9b3d4731edbb 473 }
WFKnight 0:9b3d4731edbb 474
WFKnight 0:9b3d4731edbb 475 /* QP = Q^{-1} mod P */
WFKnight 0:9b3d4731edbb 476 if( QP != NULL )
WFKnight 0:9b3d4731edbb 477 {
WFKnight 0:9b3d4731edbb 478 MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( QP, Q, P ) );
WFKnight 0:9b3d4731edbb 479 }
WFKnight 0:9b3d4731edbb 480
WFKnight 0:9b3d4731edbb 481 cleanup:
WFKnight 0:9b3d4731edbb 482 mbedtls_mpi_free( &K );
WFKnight 0:9b3d4731edbb 483
WFKnight 0:9b3d4731edbb 484 return( ret );
WFKnight 0:9b3d4731edbb 485 }
WFKnight 0:9b3d4731edbb 486
WFKnight 0:9b3d4731edbb 487 #endif /* MBEDTLS_RSA_C */