148 lines
5.8 KiB
C
148 lines
5.8 KiB
C
/**
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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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#if defined(MBEDTLS_BIGNUM_C)
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#include "mbedtls/bignum.h"
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#endif
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#if defined(MBEDTLS_SSL_TLS_C)
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#include "ssl_misc.h"
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#endif
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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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unsigned mbedtls_cf_uint_mask( unsigned value );
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size_t mbedtls_cf_size_mask( size_t bit );
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size_t mbedtls_cf_size_mask_lt( size_t x, size_t y );
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size_t mbedtls_cf_size_mask_ge( size_t x, size_t y );
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size_t mbedtls_cf_size_bool_eq( size_t x, size_t y );
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unsigned mbedtls_cf_size_gt( size_t size, size_t max );
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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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unsigned mbedtls_cf_uint_if( unsigned cond, unsigned if1, unsigned if0 );
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int mbedtls_cf_cond_select_sign( int a, int b, unsigned char second );
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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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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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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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/** 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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#if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC)
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/** Compute the HMAC of variable-length data with constant flow.
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*
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* This function computes the HMAC of the concatenation of \p add_data and \p
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* data, and does with a code flow and memory access pattern that does not
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* depend on \p data_len_secret, but only on \p min_data_len and \p
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* max_data_len. In particular, this function always reads exactly \p
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* max_data_len bytes from \p data.
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*
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* \param ctx The HMAC context. It must have keys configured
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* with mbedtls_md_hmac_starts() and use one of the
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* following hashes: SHA-384, SHA-256, SHA-1 or MD-5.
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* It is reset using mbedtls_md_hmac_reset() after
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* the computation is complete to prepare for the
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* next computation.
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* \param add_data The additional data prepended to \p data. This
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* must point to a readable buffer of \p add_data_len
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* bytes.
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* \param add_data_len The length of \p add_data in bytes.
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* \param data The data appended to \p add_data. This must point
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* to a readable buffer of \p max_data_len bytes.
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* \param data_len_secret The length of the data to process in \p data.
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* This must be no less than \p min_data_len and no
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* greater than \p max_data_len.
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* \param min_data_len The minimal length of \p data in bytes.
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* \param max_data_len The maximal length of \p data in bytes.
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* \param output The HMAC will be written here. This must point to
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* a writable buffer of sufficient size to hold the
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* HMAC value.
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*
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* \retval 0 on success.
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* \retval MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED
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* The hardware accelerator failed.
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*/
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int mbedtls_ssl_cf_hmac(
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mbedtls_md_context_t *ctx,
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const unsigned char *add_data, size_t add_data_len,
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const unsigned char *data, size_t data_len_secret,
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size_t min_data_len, size_t max_data_len,
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unsigned char *output );
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#endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */
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