290 lines
9.5 KiB
C
290 lines
9.5 KiB
C
/**
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* \file entropy.h
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*
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* \brief Entropy accumulator implementation
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*/
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/*
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* Copyright (C) 2006-2016, ARM Limited, All Rights Reserved
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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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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#ifndef MBEDTLS_ENTROPY_H
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#define MBEDTLS_ENTROPY_H
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#include <stddef.h>
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#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256)
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#include "sha512.h"
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#define MBEDTLS_ENTROPY_SHA512_ACCUMULATOR
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#else
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#if defined(MBEDTLS_SHA256_C)
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#define MBEDTLS_ENTROPY_SHA256_ACCUMULATOR
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#include "sha256.h"
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#endif
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#endif
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#if defined(MBEDTLS_THREADING_C)
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#include "threading.h"
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#endif
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#if defined(MBEDTLS_HAVEGE_C)
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#include "havege.h"
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#endif
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#define MBEDTLS_ERR_ENTROPY_SOURCE_FAILED -0x003C /**< Critical entropy source failure. */
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#define MBEDTLS_ERR_ENTROPY_MAX_SOURCES -0x003E /**< No more sources can be added. */
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#define MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED -0x0040 /**< No sources have been added to poll. */
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#define MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE -0x003D /**< No strong sources have been added to poll. */
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#define MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR -0x003F /**< Read/write error in file. */
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/**
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* \name SECTION: Module settings
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*
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* The configuration options you can set for this module are in this section.
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* Either change them in config.h or define them on the compiler command line.
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* \{
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*/
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#if !defined(MBEDTLS_ENTROPY_MAX_SOURCES)
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#define MBEDTLS_ENTROPY_MAX_SOURCES 20 /**< Maximum number of sources supported */
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#endif
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#if !defined(MBEDTLS_ENTROPY_MAX_GATHER)
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#define MBEDTLS_ENTROPY_MAX_GATHER 128 /**< Maximum amount requested from entropy sources */
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#endif
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/* \} name SECTION: Module settings */
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#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
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#define MBEDTLS_ENTROPY_BLOCK_SIZE 64 /**< Block size of entropy accumulator (SHA-512) */
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#else
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#define MBEDTLS_ENTROPY_BLOCK_SIZE 32 /**< Block size of entropy accumulator (SHA-256) */
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#endif
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#define MBEDTLS_ENTROPY_MAX_SEED_SIZE 1024 /**< Maximum size of seed we read from seed file */
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#define MBEDTLS_ENTROPY_SOURCE_MANUAL MBEDTLS_ENTROPY_MAX_SOURCES
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#define MBEDTLS_ENTROPY_SOURCE_STRONG 1 /**< Entropy source is strong */
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#define MBEDTLS_ENTROPY_SOURCE_WEAK 0 /**< Entropy source is weak */
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* \brief Entropy poll callback pointer
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*
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* \param data Callback-specific data pointer
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* \param output Data to fill
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* \param len Maximum size to provide
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* \param olen The actual amount of bytes put into the buffer (Can be 0)
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*
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* \return 0 if no critical failures occurred,
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* MBEDTLS_ERR_ENTROPY_SOURCE_FAILED otherwise
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*/
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typedef int (*mbedtls_entropy_f_source_ptr)(void *data, unsigned char *output, size_t len,
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size_t *olen);
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/**
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* \brief Entropy source state
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*/
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typedef struct mbedtls_entropy_source_state
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{
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mbedtls_entropy_f_source_ptr f_source; /**< The entropy source callback */
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void * p_source; /**< The callback data pointer */
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size_t size; /**< Amount received in bytes */
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size_t threshold; /**< Minimum bytes required before release */
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int strong; /**< Is the source strong? */
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}
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mbedtls_entropy_source_state;
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/**
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* \brief Entropy context structure
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*/
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typedef struct mbedtls_entropy_context
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{
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int accumulator_started;
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#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
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mbedtls_sha512_context accumulator;
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#else
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mbedtls_sha256_context accumulator;
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#endif
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int source_count;
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mbedtls_entropy_source_state source[MBEDTLS_ENTROPY_MAX_SOURCES];
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#if defined(MBEDTLS_HAVEGE_C)
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mbedtls_havege_state havege_data;
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#endif
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#if defined(MBEDTLS_THREADING_C)
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mbedtls_threading_mutex_t mutex; /*!< mutex */
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#endif
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#if defined(MBEDTLS_ENTROPY_NV_SEED)
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int initial_entropy_run;
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#endif
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}
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mbedtls_entropy_context;
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/**
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* \brief Initialize the context
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*
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* \param ctx Entropy context to initialize
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*/
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void mbedtls_entropy_init( mbedtls_entropy_context *ctx );
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/**
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* \brief Free the data in the context
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*
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* \param ctx Entropy context to free
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*/
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void mbedtls_entropy_free( mbedtls_entropy_context *ctx );
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/**
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* \brief Adds an entropy source to poll
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* (Thread-safe if MBEDTLS_THREADING_C is enabled)
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*
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* \param ctx Entropy context
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* \param f_source Entropy function
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* \param p_source Function data
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* \param threshold Minimum required from source before entropy is released
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* ( with mbedtls_entropy_func() ) (in bytes)
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* \param strong MBEDTLS_ENTROPY_SOURCE_STRONG or
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* MBEDTLS_ENTROPY_SOURCE_WEAK.
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* At least one strong source needs to be added.
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* Weaker sources (such as the cycle counter) can be used as
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* a complement.
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*
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* \return 0 if successful or MBEDTLS_ERR_ENTROPY_MAX_SOURCES
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*/
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int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx,
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mbedtls_entropy_f_source_ptr f_source, void *p_source,
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size_t threshold, int strong );
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/**
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* \brief Trigger an extra gather poll for the accumulator
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* (Thread-safe if MBEDTLS_THREADING_C is enabled)
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*
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* \param ctx Entropy context
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*
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* \return 0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
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*/
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int mbedtls_entropy_gather( mbedtls_entropy_context *ctx );
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/**
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* \brief Retrieve entropy from the accumulator
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* (Maximum length: MBEDTLS_ENTROPY_BLOCK_SIZE)
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* (Thread-safe if MBEDTLS_THREADING_C is enabled)
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*
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* \param data Entropy context
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* \param output Buffer to fill
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* \param len Number of bytes desired, must be at most MBEDTLS_ENTROPY_BLOCK_SIZE
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*
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* \return 0 if successful, or MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
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*/
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int mbedtls_entropy_func( void *data, unsigned char *output, size_t len );
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/**
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* \brief Add data to the accumulator manually
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* (Thread-safe if MBEDTLS_THREADING_C is enabled)
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*
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* \param ctx Entropy context
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* \param data Data to add
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* \param len Length of data
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*
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* \return 0 if successful
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*/
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int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx,
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const unsigned char *data, size_t len );
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#if defined(MBEDTLS_ENTROPY_NV_SEED)
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/**
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* \brief Trigger an update of the seed file in NV by using the
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* current entropy pool.
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*
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* \param ctx Entropy context
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*
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* \return 0 if successful
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*/
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int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx );
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#endif /* MBEDTLS_ENTROPY_NV_SEED */
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#if defined(MBEDTLS_FS_IO)
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/**
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* \brief Write a seed file
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*
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* \param ctx Entropy context
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* \param path Name of the file
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*
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* \return 0 if successful,
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* MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR on file error, or
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* MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
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*/
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int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path );
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/**
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* \brief Read and update a seed file. Seed is added to this
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* instance. No more than MBEDTLS_ENTROPY_MAX_SEED_SIZE bytes are
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* read from the seed file. The rest is ignored.
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*
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* \param ctx Entropy context
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* \param path Name of the file
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*
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* \return 0 if successful,
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* MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR on file error,
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* MBEDTLS_ERR_ENTROPY_SOURCE_FAILED
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*/
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int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path );
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#endif /* MBEDTLS_FS_IO */
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#if defined(MBEDTLS_SELF_TEST)
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/**
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* \brief Checkup routine
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*
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* This module self-test also calls the entropy self-test,
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* mbedtls_entropy_source_self_test();
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*
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* \return 0 if successful, or 1 if a test failed
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*/
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int mbedtls_entropy_self_test( int verbose );
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#if defined(MBEDTLS_ENTROPY_HARDWARE_ALT)
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/**
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* \brief Checkup routine
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*
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* Verifies the integrity of the hardware entropy source
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* provided by the function 'mbedtls_hardware_poll()'.
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*
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* Note this is the only hardware entropy source that is known
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* at link time, and other entropy sources configured
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* dynamically at runtime by the function
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* mbedtls_entropy_add_source() will not be tested.
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*
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* \return 0 if successful, or 1 if a test failed
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*/
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int mbedtls_entropy_source_self_test( int verbose );
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#endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */
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#endif /* MBEDTLS_SELF_TEST */
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#ifdef __cplusplus
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}
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#endif
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#endif /* entropy.h */
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