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https://github.com/Mbed-TLS/mbedtls.git
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b62bad442e
We want to make sure that the value has at least as many limbs allocated as the modulus as we need this to be able to do any operations in constant time. An invariant of the API is that the residue values are canonical, make sure that the residue is compared to the entire modulus. Signed-off-by: Janos Follath <janos.follath@arm.com>
277 lines
6.6 KiB
C
277 lines
6.6 KiB
C
/**
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* Modular bignum functions
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "common.h"
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#if defined(MBEDTLS_BIGNUM_C)
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#include <string.h>
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#include "mbedtls/platform_util.h"
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#include "mbedtls/error.h"
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#include "mbedtls/bignum.h"
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#include "mbedtls/platform.h"
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#include "bignum_core.h"
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#include "bignum_mod.h"
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#include "bignum_mod_raw.h"
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#include "constant_time_internal.h"
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int mbedtls_mpi_mod_residue_setup( mbedtls_mpi_mod_residue *r,
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const mbedtls_mpi_mod_modulus *m,
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mbedtls_mpi_uint *p,
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size_t p_limbs )
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{
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if( p_limbs < m->limbs || !mbedtls_mpi_core_lt_ct( p, m->p, m->limbs ) )
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return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
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r->limbs = m->limbs;
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r->p = p;
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return( 0 );
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}
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void mbedtls_mpi_mod_residue_release( mbedtls_mpi_mod_residue *r )
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{
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if ( r == NULL )
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return;
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r->limbs = 0;
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r->p = NULL;
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}
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void mbedtls_mpi_mod_modulus_init( mbedtls_mpi_mod_modulus *m )
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{
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if ( m == NULL )
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return;
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m->p = NULL;
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m->limbs = 0;
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m->bits = 0;
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m->ext_rep = MBEDTLS_MPI_MOD_EXT_REP_INVALID;
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m->int_rep = MBEDTLS_MPI_MOD_REP_INVALID;
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}
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void mbedtls_mpi_mod_modulus_free( mbedtls_mpi_mod_modulus *m )
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{
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if ( m == NULL )
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return;
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switch( m->int_rep )
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{
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case MBEDTLS_MPI_MOD_REP_MONTGOMERY:
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if (m->rep.mont.rr != NULL)
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{
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mbedtls_platform_zeroize( (mbedtls_mpi_uint *) m->rep.mont.rr,
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m->limbs );
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mbedtls_free( (mbedtls_mpi_uint *)m->rep.mont.rr );
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m->rep.mont.rr = NULL;
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}
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m->rep.mont.mm = 0;
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break;
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case MBEDTLS_MPI_MOD_REP_OPT_RED:
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mbedtls_free( m->rep.ored );
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break;
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case MBEDTLS_MPI_MOD_REP_INVALID:
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break;
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}
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m->p = NULL;
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m->limbs = 0;
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m->bits = 0;
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m->ext_rep = MBEDTLS_MPI_MOD_EXT_REP_INVALID;
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m->int_rep = MBEDTLS_MPI_MOD_REP_INVALID;
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}
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static int set_mont_const_square( const mbedtls_mpi_uint **X,
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const mbedtls_mpi_uint *A,
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size_t limbs )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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mbedtls_mpi N;
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mbedtls_mpi RR;
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*X = NULL;
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mbedtls_mpi_init( &N );
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mbedtls_mpi_init( &RR );
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if ( A == NULL || limbs == 0 || limbs >= ( MBEDTLS_MPI_MAX_LIMBS / 2 ) - 2 )
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goto cleanup;
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if ( mbedtls_mpi_grow( &N, limbs ) )
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goto cleanup;
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memcpy( N.p, A, sizeof(mbedtls_mpi_uint) * limbs );
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ret = mbedtls_mpi_core_get_mont_r2_unsafe(&RR, &N);
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if ( ret == 0 )
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{
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*X = RR.p;
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RR.p = NULL;
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}
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cleanup:
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mbedtls_mpi_free(&N);
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mbedtls_mpi_free(&RR);
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ret = ( ret != 0 ) ? MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED : 0;
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return( ret );
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}
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int mbedtls_mpi_mod_modulus_setup( mbedtls_mpi_mod_modulus *m,
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const mbedtls_mpi_uint *p,
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size_t p_limbs,
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mbedtls_mpi_mod_ext_rep ext_rep,
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mbedtls_mpi_mod_rep_selector int_rep )
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{
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int ret = 0;
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m->p = p;
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m->limbs = p_limbs;
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m->bits = mbedtls_mpi_core_bitlen( p, p_limbs );
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switch( ext_rep )
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{
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case MBEDTLS_MPI_MOD_EXT_REP_LE:
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case MBEDTLS_MPI_MOD_EXT_REP_BE:
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m->ext_rep = ext_rep;
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break;
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default:
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ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
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goto exit;
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}
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switch( int_rep )
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{
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case MBEDTLS_MPI_MOD_REP_MONTGOMERY:
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m->int_rep = int_rep;
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m->rep.mont.mm = mbedtls_mpi_core_montmul_init( m->p );
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ret = set_mont_const_square( &m->rep.mont.rr, m->p, m->limbs );
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break;
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case MBEDTLS_MPI_MOD_REP_OPT_RED:
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m->int_rep = int_rep;
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m->rep.ored = NULL;
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break;
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default:
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ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
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goto exit;
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}
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exit:
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if( ret != 0 )
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{
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mbedtls_mpi_mod_modulus_free( m );
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}
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return( ret );
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}
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/* BEGIN MERGE SLOT 1 */
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/* END MERGE SLOT 1 */
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/* BEGIN MERGE SLOT 2 */
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/* END MERGE SLOT 2 */
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/* BEGIN MERGE SLOT 3 */
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/* END MERGE SLOT 3 */
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/* BEGIN MERGE SLOT 4 */
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/* END MERGE SLOT 4 */
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/* BEGIN MERGE SLOT 5 */
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/* END MERGE SLOT 5 */
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/* BEGIN MERGE SLOT 6 */
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/* END MERGE SLOT 6 */
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/* BEGIN MERGE SLOT 7 */
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int mbedtls_mpi_mod_read( mbedtls_mpi_mod_residue *r,
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const mbedtls_mpi_mod_modulus *m,
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const unsigned char *buf,
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size_t buflen )
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{
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int ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
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if ( r == NULL || m == NULL )
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goto cleanup;
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if ( r->p == NULL || m->p == NULL || r->limbs > m->limbs ||
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r->limbs == 0 || m->limbs == 0 )
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goto cleanup;
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ret = mbedtls_mpi_mod_raw_read( r->p, m, buf, buflen );
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if( ret != 0 )
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goto cleanup;
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r->limbs = m->limbs;
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if (m->int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY)
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ret = mbedtls_mpi_mod_raw_to_mont_rep(r->p, m);
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cleanup:
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return ( ret );
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}
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int mbedtls_mpi_mod_write( const mbedtls_mpi_mod_residue *r,
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const mbedtls_mpi_mod_modulus *m,
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unsigned char *buf,
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size_t buflen )
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{
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int ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA;
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if ( r == NULL || m == NULL )
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goto cleanup;
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if ( r->p == NULL || m->p == NULL || r->limbs > m->limbs ||
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r->limbs == 0 || m->limbs == 0 )
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goto cleanup;
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if ( m->int_rep == MBEDTLS_MPI_MOD_REP_MONTGOMERY)
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ret = mbedtls_mpi_mod_raw_from_mont_rep( r->p, m );
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ret = mbedtls_mpi_mod_raw_write( r->p, m, buf, buflen );
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cleanup:
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return ( ret );
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}
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/* END MERGE SLOT 7 */
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/* BEGIN MERGE SLOT 8 */
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/* END MERGE SLOT 8 */
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/* BEGIN MERGE SLOT 9 */
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/* END MERGE SLOT 9 */
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/* BEGIN MERGE SLOT 10 */
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/* END MERGE SLOT 10 */
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#endif /* MBEDTLS_BIGNUM_C */
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