2021-09-27 11:28:54 +02:00
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/**
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* Constant-time 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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2021-09-27 12:55:33 +02:00
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#if defined(MBEDTLS_BIGNUM_C)
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#include "mbedtls/bignum.h"
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#endif
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2021-09-27 11:28:54 +02:00
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#include <stddef.h>
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int mbedtls_ssl_safer_memcmp( const void *a, const void *b, size_t n );
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int mbedtls_constant_time_memcmp( const void *v1, const void *v2, size_t len );
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unsigned char mbedtls_nist_kw_safer_memcmp( const void *a, const void *b, size_t n );
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int mbedtls_safer_memcmp( const void *a, const void *b, size_t n );
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2021-09-27 11:40:03 +02:00
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unsigned mbedtls_cf_uint_mask( unsigned value );
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2021-09-27 11:49:42 +02:00
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size_t mbedtls_cf_size_mask( size_t bit );
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2021-09-27 11:53:54 +02:00
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size_t mbedtls_cf_size_mask_lt( size_t x, size_t y );
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2021-09-27 11:58:31 +02:00
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size_t mbedtls_cf_size_mask_ge( size_t x, size_t y );
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2021-09-27 12:15:19 +02:00
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size_t mbedtls_cf_size_bool_eq( size_t x, size_t y );
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2021-09-27 12:25:07 +02:00
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unsigned mbedtls_cf_size_gt( size_t size, size_t max );
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2021-09-27 12:55:33 +02:00
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#if defined(MBEDTLS_BIGNUM_C)
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unsigned mbedtls_cf_mpi_uint_lt( const mbedtls_mpi_uint x,
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const mbedtls_mpi_uint y );
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#endif /* MBEDTLS_BIGNUM_C */
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2021-09-27 12:59:30 +02:00
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unsigned mbedtls_cf_uint_if( unsigned cond, unsigned if1, unsigned if0 );
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2021-09-27 13:03:57 +02:00
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int mbedtls_cf_cond_select_sign( int a, int b, unsigned char second );
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2021-09-27 13:17:15 +02:00
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#if defined(MBEDTLS_BIGNUM_C)
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void mbedtls_cf_mpi_uint_cond_assign( size_t n,
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mbedtls_mpi_uint *dest,
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const mbedtls_mpi_uint *src,
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unsigned char assign );
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#endif /* MBEDTLS_BIGNUM_C */
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2021-09-27 13:31:06 +02:00
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void mbedtls_cf_mem_move_to_left( void *start,
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size_t total,
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size_t offset );
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2021-09-27 13:34:25 +02:00
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void mbedtls_cf_memcpy_if_eq( unsigned char *dst,
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const unsigned char *src,
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size_t len,
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size_t c1, size_t c2 );
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2021-09-27 13:57:45 +02:00
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/** Copy data from a secret position with constant flow.
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*
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* This function copies \p len bytes from \p src_base + \p offset_secret to \p
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* dst, with a code flow and memory access pattern that does not depend on \p
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* offset_secret, but only on \p offset_min, \p offset_max and \p len.
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*
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* \param dst The destination buffer. This must point to a writable
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* buffer of at least \p len bytes.
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* \param src_base The base of the source buffer. This must point to a
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* readable buffer of at least \p offset_max + \p len
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* bytes.
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* \param offset_secret The offset in the source buffer from which to copy.
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* This must be no less than \p offset_min and no greater
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* than \p offset_max.
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* \param offset_min The minimal value of \p offset_secret.
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* \param offset_max The maximal value of \p offset_secret.
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* \param len The number of bytes to copy.
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*/
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void mbedtls_cf_memcpy_offset( unsigned char *dst,
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const unsigned char *src_base,
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size_t offset_secret,
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size_t offset_min, size_t offset_max,
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size_t len );
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