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mbed client lightswitch demo
Dependencies: mbed Socket lwip-eth lwip-sys lwip
Fork of mbed-client-classic-example-lwip by
mbedtls/source/entropy.c
- Committer:
- mbedAustin
- Date:
- 2016-06-09
- Revision:
- 11:cada08fc8a70
File content as of revision 11:cada08fc8a70:
/* * Entropy accumulator implementation * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. * * This file is part of mbed TLS (https://tls.mbed.org) */ #if !defined(MBEDTLS_CONFIG_FILE) #include "mbedtls/config.h" #else #include MBEDTLS_CONFIG_FILE #endif #if defined(MBEDTLS_ENTROPY_C) #include "mbedtls/entropy.h" #include "mbedtls/entropy_poll.h" #include <string.h> #if defined(MBEDTLS_FS_IO) #include <stdio.h> #endif #if defined(MBEDTLS_SELF_TEST) #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include <stdio.h> #define mbedtls_printf printf #endif /* MBEDTLS_PLATFORM_C */ #endif /* MBEDTLS_SELF_TEST */ #if defined(MBEDTLS_HAVEGE_C) #include "mbedtls/havege.h" #endif /* Implementation that should never be optimized out by the compiler */ static void mbedtls_zeroize( void *v, size_t n ) { volatile unsigned char *p = v; while( n-- ) *p++ = 0; } #define ENTROPY_MAX_LOOP 256 /**< Maximum amount to loop before error */ void mbedtls_entropy_init( mbedtls_entropy_context *ctx ) { memset( ctx, 0, sizeof(mbedtls_entropy_context) ); #if defined(MBEDTLS_THREADING_C) mbedtls_mutex_init( &ctx->mutex ); #endif #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) mbedtls_sha512_starts( &ctx->accumulator, 0 ); #else mbedtls_sha256_starts( &ctx->accumulator, 0 ); #endif #if defined(MBEDTLS_HAVEGE_C) mbedtls_havege_init( &ctx->havege_data ); #endif #if !defined(MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES) #if !defined(MBEDTLS_NO_PLATFORM_ENTROPY) mbedtls_entropy_add_source( ctx, mbedtls_platform_entropy_poll, NULL, MBEDTLS_ENTROPY_MIN_PLATFORM, MBEDTLS_ENTROPY_SOURCE_STRONG ); #endif #if defined(MBEDTLS_TIMING_C) mbedtls_entropy_add_source( ctx, mbedtls_hardclock_poll, NULL, MBEDTLS_ENTROPY_MIN_HARDCLOCK, MBEDTLS_ENTROPY_SOURCE_WEAK ); #endif #if defined(MBEDTLS_HAVEGE_C) mbedtls_entropy_add_source( ctx, mbedtls_havege_poll, &ctx->havege_data, MBEDTLS_ENTROPY_MIN_HAVEGE, MBEDTLS_ENTROPY_SOURCE_STRONG ); #endif #if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) mbedtls_entropy_add_source( ctx, mbedtls_hardware_poll, NULL, MBEDTLS_ENTROPY_MIN_HARDWARE, MBEDTLS_ENTROPY_SOURCE_STRONG ); #endif #endif /* MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES */ } void mbedtls_entropy_free( mbedtls_entropy_context *ctx ) { #if defined(MBEDTLS_HAVEGE_C) mbedtls_havege_free( &ctx->havege_data ); #endif #if defined(MBEDTLS_THREADING_C) mbedtls_mutex_free( &ctx->mutex ); #endif mbedtls_zeroize( ctx, sizeof( mbedtls_entropy_context ) ); } int mbedtls_entropy_add_source( mbedtls_entropy_context *ctx, mbedtls_entropy_f_source_ptr f_source, void *p_source, size_t threshold, int strong ) { int index, ret = 0; #if defined(MBEDTLS_THREADING_C) if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) return( ret ); #endif index = ctx->source_count; if( index >= MBEDTLS_ENTROPY_MAX_SOURCES ) { ret = MBEDTLS_ERR_ENTROPY_MAX_SOURCES; goto exit; } ctx->source[index].f_source = f_source; ctx->source[index].p_source = p_source; ctx->source[index].threshold = threshold; ctx->source[index].strong = strong; ctx->source_count++; exit: #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); #endif return( ret ); } /* * Entropy accumulator update */ static int entropy_update( mbedtls_entropy_context *ctx, unsigned char source_id, const unsigned char *data, size_t len ) { unsigned char header[2]; unsigned char tmp[MBEDTLS_ENTROPY_BLOCK_SIZE]; size_t use_len = len; const unsigned char *p = data; if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE ) { #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) mbedtls_sha512( data, len, tmp, 0 ); #else mbedtls_sha256( data, len, tmp, 0 ); #endif p = tmp; use_len = MBEDTLS_ENTROPY_BLOCK_SIZE; } header[0] = source_id; header[1] = use_len & 0xFF; #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) mbedtls_sha512_update( &ctx->accumulator, header, 2 ); mbedtls_sha512_update( &ctx->accumulator, p, use_len ); #else mbedtls_sha256_update( &ctx->accumulator, header, 2 ); mbedtls_sha256_update( &ctx->accumulator, p, use_len ); #endif return( 0 ); } int mbedtls_entropy_update_manual( mbedtls_entropy_context *ctx, const unsigned char *data, size_t len ) { int ret; #if defined(MBEDTLS_THREADING_C) if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) return( ret ); #endif ret = entropy_update( ctx, MBEDTLS_ENTROPY_SOURCE_MANUAL, data, len ); #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); #endif return( ret ); } /* * Run through the different sources to add entropy to our accumulator */ static int entropy_gather_internal( mbedtls_entropy_context *ctx ) { int ret, i, have_one_strong = 0; unsigned char buf[MBEDTLS_ENTROPY_MAX_GATHER]; size_t olen; if( ctx->source_count == 0 ) return( MBEDTLS_ERR_ENTROPY_NO_SOURCES_DEFINED ); /* * Run through our entropy sources */ for( i = 0; i < ctx->source_count; i++ ) { if( ctx->source[i].strong == MBEDTLS_ENTROPY_SOURCE_STRONG ) have_one_strong = 1; olen = 0; if( ( ret = ctx->source[i].f_source( ctx->source[i].p_source, buf, MBEDTLS_ENTROPY_MAX_GATHER, &olen ) ) != 0 ) { return( ret ); } /* * Add if we actually gathered something */ if( olen > 0 ) { entropy_update( ctx, (unsigned char) i, buf, olen ); ctx->source[i].size += olen; } } if( have_one_strong == 0 ) return( MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE ); return( 0 ); } /* * Thread-safe wrapper for entropy_gather_internal() */ int mbedtls_entropy_gather( mbedtls_entropy_context *ctx ) { int ret; #if defined(MBEDTLS_THREADING_C) if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) return( ret ); #endif ret = entropy_gather_internal( ctx ); #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); #endif return( ret ); } int mbedtls_entropy_func( void *data, unsigned char *output, size_t len ) { int ret, count = 0, i, done; mbedtls_entropy_context *ctx = (mbedtls_entropy_context *) data; unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; if( len > MBEDTLS_ENTROPY_BLOCK_SIZE ) return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED ); #if defined(MBEDTLS_THREADING_C) if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) return( ret ); #endif /* * Always gather extra entropy before a call */ do { if( count++ > ENTROPY_MAX_LOOP ) { ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; goto exit; } if( ( ret = entropy_gather_internal( ctx ) ) != 0 ) goto exit; done = 1; for( i = 0; i < ctx->source_count; i++ ) if( ctx->source[i].size < ctx->source[i].threshold ) done = 0; } while( ! done ); memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE ); #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) mbedtls_sha512_finish( &ctx->accumulator, buf ); /* * Reset accumulator and counters and recycle existing entropy */ memset( &ctx->accumulator, 0, sizeof( mbedtls_sha512_context ) ); mbedtls_sha512_starts( &ctx->accumulator, 0 ); mbedtls_sha512_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ); /* * Perform second SHA-512 on entropy */ mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 ); #else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */ mbedtls_sha256_finish( &ctx->accumulator, buf ); /* * Reset accumulator and counters and recycle existing entropy */ memset( &ctx->accumulator, 0, sizeof( mbedtls_sha256_context ) ); mbedtls_sha256_starts( &ctx->accumulator, 0 ); mbedtls_sha256_update( &ctx->accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ); /* * Perform second SHA-256 on entropy */ mbedtls_sha256( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, buf, 0 ); #endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */ for( i = 0; i < ctx->source_count; i++ ) ctx->source[i].size = 0; memcpy( output, buf, len ); ret = 0; exit: #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); #endif return( ret ); } #if defined(MBEDTLS_FS_IO) int mbedtls_entropy_write_seed_file( mbedtls_entropy_context *ctx, const char *path ) { int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; FILE *f; unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; if( ( f = fopen( path, "wb" ) ) == NULL ) return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) goto exit; if( fwrite( buf, 1, MBEDTLS_ENTROPY_BLOCK_SIZE, f ) != MBEDTLS_ENTROPY_BLOCK_SIZE ) { ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; goto exit; } ret = 0; exit: fclose( f ); return( ret ); } int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path ) { FILE *f; size_t n; unsigned char buf[ MBEDTLS_ENTROPY_MAX_SEED_SIZE ]; if( ( f = fopen( path, "rb" ) ) == NULL ) return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); fseek( f, 0, SEEK_END ); n = (size_t) ftell( f ); fseek( f, 0, SEEK_SET ); if( n > MBEDTLS_ENTROPY_MAX_SEED_SIZE ) n = MBEDTLS_ENTROPY_MAX_SEED_SIZE; if( fread( buf, 1, n, f ) != n ) { fclose( f ); return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); } fclose( f ); mbedtls_entropy_update_manual( ctx, buf, n ); return( mbedtls_entropy_write_seed_file( ctx, path ) ); } #endif /* MBEDTLS_FS_IO */ #if defined(MBEDTLS_SELF_TEST) /* * Dummy source function */ static int entropy_dummy_source( void *data, unsigned char *output, size_t len, size_t *olen ) { ((void) data); memset( output, 0x2a, len ); *olen = len; return( 0 ); } /* * The actual entropy quality is hard to test, but we can at least * test that the functions don't cause errors and write the correct * amount of data to buffers. */ int mbedtls_entropy_self_test( int verbose ) { int ret = 0; mbedtls_entropy_context ctx; unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 }; unsigned char acc[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 }; size_t i, j; if( verbose != 0 ) mbedtls_printf( " ENTROPY test: " ); mbedtls_entropy_init( &ctx ); /* First do a gather to make sure we have default sources */ if( ( ret = mbedtls_entropy_gather( &ctx ) ) != 0 ) goto cleanup; ret = mbedtls_entropy_add_source( &ctx, entropy_dummy_source, NULL, 16, MBEDTLS_ENTROPY_SOURCE_WEAK ); if( ret != 0 ) goto cleanup; if( ( ret = mbedtls_entropy_update_manual( &ctx, buf, sizeof buf ) ) != 0 ) goto cleanup; /* * To test that mbedtls_entropy_func writes correct number of bytes: * - use the whole buffer and rely on ASan to detect overruns * - collect entropy 8 times and OR the result in an accumulator: * any byte should then be 0 with probably 2^(-64), so requiring * each of the 32 or 64 bytes to be non-zero has a false failure rate * of at most 2^(-58) which is acceptable. */ for( i = 0; i < 8; i++ ) { if( ( ret = mbedtls_entropy_func( &ctx, buf, sizeof( buf ) ) ) != 0 ) goto cleanup; for( j = 0; j < sizeof( buf ); j++ ) acc[j] |= buf[j]; } for( j = 0; j < sizeof( buf ); j++ ) { if( acc[j] == 0 ) { ret = 1; goto cleanup; } } cleanup: mbedtls_entropy_free( &ctx ); if( verbose != 0 ) { if( ret != 0 ) mbedtls_printf( "failed\n" ); else mbedtls_printf( "passed\n" ); mbedtls_printf( "\n" ); } return( ret != 0 ); } #endif /* MBEDTLS_SELF_TEST */ #endif /* MBEDTLS_ENTROPY_C */