/* | |
* Entropy accumulator implementation | |
* | |
* Copyright (C) 2006-2016, 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) | |
#if defined(MBEDTLS_TEST_NULL_ENTROPY) | |
#warning "**** WARNING! MBEDTLS_TEST_NULL_ENTROPY defined! " | |
#warning "**** THIS BUILD HAS NO DEFINED ENTROPY SOURCES " | |
#warning "**** THIS BUILD IS *NOT* SUITABLE FOR PRODUCTION USE " | |
#endif | |
#include "mbedtls/entropy.h" | |
#include "mbedtls/entropy_poll.h" | |
#include "mbedtls/platform_util.h" | |
#include <string.h> | |
#if defined(MBEDTLS_FS_IO) | |
#include <stdio.h> | |
#endif | |
#if defined(MBEDTLS_ENTROPY_NV_SEED) | |
#include "mbedtls/platform.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 | |
#define ENTROPY_MAX_LOOP 256 /**< Maximum amount to loop before error */ | |
void mbedtls_entropy_init( mbedtls_entropy_context *ctx ) | |
{ | |
ctx->source_count = 0; | |
memset( ctx->source, 0, sizeof( ctx->source ) ); | |
#if defined(MBEDTLS_THREADING_C) | |
mbedtls_mutex_init( &ctx->mutex ); | |
#endif | |
ctx->accumulator_started = 0; | |
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) | |
mbedtls_sha512_init( &ctx->accumulator ); | |
#else | |
mbedtls_sha256_init( &ctx->accumulator ); | |
#endif | |
#if defined(MBEDTLS_HAVEGE_C) | |
mbedtls_havege_init( &ctx->havege_data ); | |
#endif | |
/* Reminder: Update ENTROPY_HAVE_STRONG in the test files | |
* when adding more strong entropy sources here. */ | |
#if defined(MBEDTLS_TEST_NULL_ENTROPY) | |
mbedtls_entropy_add_source( ctx, mbedtls_null_entropy_poll, NULL, | |
1, MBEDTLS_ENTROPY_SOURCE_STRONG ); | |
#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 | |
#if defined(MBEDTLS_ENTROPY_NV_SEED) | |
mbedtls_entropy_add_source( ctx, mbedtls_nv_seed_poll, NULL, | |
MBEDTLS_ENTROPY_BLOCK_SIZE, | |
MBEDTLS_ENTROPY_SOURCE_STRONG ); | |
ctx->initial_entropy_run = 0; | |
#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 | |
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) | |
mbedtls_sha512_free( &ctx->accumulator ); | |
#else | |
mbedtls_sha256_free( &ctx->accumulator ); | |
#endif | |
#if defined(MBEDTLS_ENTROPY_NV_SEED) | |
ctx->initial_entropy_run = 0; | |
#endif | |
ctx->source_count = 0; | |
mbedtls_platform_zeroize( ctx->source, sizeof( ctx->source ) ); | |
ctx->accumulator_started = 0; | |
} | |
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 idx, ret = 0; | |
#if defined(MBEDTLS_THREADING_C) | |
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) | |
return( ret ); | |
#endif | |
idx = ctx->source_count; | |
if( idx >= MBEDTLS_ENTROPY_MAX_SOURCES ) | |
{ | |
ret = MBEDTLS_ERR_ENTROPY_MAX_SOURCES; | |
goto exit; | |
} | |
ctx->source[idx].f_source = f_source; | |
ctx->source[idx].p_source = p_source; | |
ctx->source[idx].threshold = threshold; | |
ctx->source[idx].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; | |
int ret = 0; | |
if( use_len > MBEDTLS_ENTROPY_BLOCK_SIZE ) | |
{ | |
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) | |
if( ( ret = mbedtls_sha512_ret( data, len, tmp, 0 ) ) != 0 ) | |
goto cleanup; | |
#else | |
if( ( ret = mbedtls_sha256_ret( data, len, tmp, 0 ) ) != 0 ) | |
goto cleanup; | |
#endif | |
p = tmp; | |
use_len = MBEDTLS_ENTROPY_BLOCK_SIZE; | |
} | |
header[0] = source_id; | |
header[1] = use_len & 0xFF; | |
/* | |
* Start the accumulator if this has not already happened. Note that | |
* it is sufficient to start the accumulator here only because all calls to | |
* gather entropy eventually execute this code. | |
*/ | |
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR) | |
if( ctx->accumulator_started == 0 && | |
( ret = mbedtls_sha512_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) | |
goto cleanup; | |
else | |
ctx->accumulator_started = 1; | |
if( ( ret = mbedtls_sha512_update_ret( &ctx->accumulator, header, 2 ) ) != 0 ) | |
goto cleanup; | |
ret = mbedtls_sha512_update_ret( &ctx->accumulator, p, use_len ); | |
#else | |
if( ctx->accumulator_started == 0 && | |
( ret = mbedtls_sha256_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) | |
goto cleanup; | |
else | |
ctx->accumulator_started = 1; | |
if( ( ret = mbedtls_sha256_update_ret( &ctx->accumulator, header, 2 ) ) != 0 ) | |
goto cleanup; | |
ret = mbedtls_sha256_update_ret( &ctx->accumulator, p, use_len ); | |
#endif | |
cleanup: | |
mbedtls_platform_zeroize( tmp, sizeof( tmp ) ); | |
return( ret ); | |
} | |
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 ) | |
{ | |
goto cleanup; | |
} | |
/* | |
* Add if we actually gathered something | |
*/ | |
if( olen > 0 ) | |
{ | |
if( ( ret = entropy_update( ctx, (unsigned char) i, | |
buf, olen ) ) != 0 ) | |
return( ret ); | |
ctx->source[i].size += olen; | |
} | |
} | |
if( have_one_strong == 0 ) | |
ret = MBEDTLS_ERR_ENTROPY_NO_STRONG_SOURCE; | |
cleanup: | |
mbedtls_platform_zeroize( buf, sizeof( buf ) ); | |
return( ret ); | |
} | |
/* | |
* 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_ENTROPY_NV_SEED) | |
/* Update the NV entropy seed before generating any entropy for outside | |
* use. | |
*/ | |
if( ctx->initial_entropy_run == 0 ) | |
{ | |
ctx->initial_entropy_run = 1; | |
if( ( ret = mbedtls_entropy_update_nv_seed( ctx ) ) != 0 ) | |
return( ret ); | |
} | |
#endif | |
#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) | |
/* | |
* Note that at this stage it is assumed that the accumulator was started | |
* in a previous call to entropy_update(). If this is not guaranteed, the | |
* code below will fail. | |
*/ | |
if( ( ret = mbedtls_sha512_finish_ret( &ctx->accumulator, buf ) ) != 0 ) | |
goto exit; | |
/* | |
* Reset accumulator and counters and recycle existing entropy | |
*/ | |
mbedtls_sha512_free( &ctx->accumulator ); | |
mbedtls_sha512_init( &ctx->accumulator ); | |
if( ( ret = mbedtls_sha512_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_sha512_update_ret( &ctx->accumulator, buf, | |
MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) | |
goto exit; | |
/* | |
* Perform second SHA-512 on entropy | |
*/ | |
if( ( ret = mbedtls_sha512_ret( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, | |
buf, 0 ) ) != 0 ) | |
goto exit; | |
#else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */ | |
if( ( ret = mbedtls_sha256_finish_ret( &ctx->accumulator, buf ) ) != 0 ) | |
goto exit; | |
/* | |
* Reset accumulator and counters and recycle existing entropy | |
*/ | |
mbedtls_sha256_free( &ctx->accumulator ); | |
mbedtls_sha256_init( &ctx->accumulator ); | |
if( ( ret = mbedtls_sha256_starts_ret( &ctx->accumulator, 0 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_sha256_update_ret( &ctx->accumulator, buf, | |
MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) | |
goto exit; | |
/* | |
* Perform second SHA-256 on entropy | |
*/ | |
if( ( ret = mbedtls_sha256_ret( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, | |
buf, 0 ) ) != 0 ) | |
goto exit; | |
#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: | |
mbedtls_platform_zeroize( buf, sizeof( buf ) ); | |
#if defined(MBEDTLS_THREADING_C) | |
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) | |
return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); | |
#endif | |
return( ret ); | |
} | |
#if defined(MBEDTLS_ENTROPY_NV_SEED) | |
int mbedtls_entropy_update_nv_seed( mbedtls_entropy_context *ctx ) | |
{ | |
int ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; | |
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; | |
/* Read new seed and write it to NV */ | |
if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) | |
return( ret ); | |
if( mbedtls_nv_seed_write( buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) < 0 ) | |
return( MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR ); | |
/* Manually update the remaining stream with a separator value to diverge */ | |
memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE ); | |
ret = mbedtls_entropy_update_manual( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ); | |
return( ret ); | |
} | |
#endif /* MBEDTLS_ENTROPY_NV_SEED */ | |
#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: | |
mbedtls_platform_zeroize( buf, sizeof( buf ) ); | |
fclose( f ); | |
return( ret ); | |
} | |
int mbedtls_entropy_update_seed_file( mbedtls_entropy_context *ctx, const char *path ) | |
{ | |
int ret = 0; | |
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 ) | |
ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; | |
else | |
ret = mbedtls_entropy_update_manual( ctx, buf, n ); | |
fclose( f ); | |
mbedtls_platform_zeroize( buf, sizeof( buf ) ); | |
if( ret != 0 ) | |
return( ret ); | |
return( mbedtls_entropy_write_seed_file( ctx, path ) ); | |
} | |
#endif /* MBEDTLS_FS_IO */ | |
#if defined(MBEDTLS_SELF_TEST) | |
#if !defined(MBEDTLS_TEST_NULL_ENTROPY) | |
/* | |
* 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 ); | |
} | |
#endif /* !MBEDTLS_TEST_NULL_ENTROPY */ | |
#if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) | |
static int mbedtls_entropy_source_self_test_gather( unsigned char *buf, size_t buf_len ) | |
{ | |
int ret = 0; | |
size_t entropy_len = 0; | |
size_t olen = 0; | |
size_t attempts = buf_len; | |
while( attempts > 0 && entropy_len < buf_len ) | |
{ | |
if( ( ret = mbedtls_hardware_poll( NULL, buf + entropy_len, | |
buf_len - entropy_len, &olen ) ) != 0 ) | |
return( ret ); | |
entropy_len += olen; | |
attempts--; | |
} | |
if( entropy_len < buf_len ) | |
{ | |
ret = 1; | |
} | |
return( ret ); | |
} | |
static int mbedtls_entropy_source_self_test_check_bits( const unsigned char *buf, | |
size_t buf_len ) | |
{ | |
unsigned char set= 0xFF; | |
unsigned char unset = 0x00; | |
size_t i; | |
for( i = 0; i < buf_len; i++ ) | |
{ | |
set &= buf[i]; | |
unset |= buf[i]; | |
} | |
return( set == 0xFF || unset == 0x00 ); | |
} | |
/* | |
* A test to ensure hat the entropy sources are functioning correctly | |
* and there is no obvious failure. The test performs the following checks: | |
* - The entropy source is not providing only 0s (all bits unset) or 1s (all | |
* bits set). | |
* - The entropy source is not providing values in a pattern. Because the | |
* hardware could be providing data in an arbitrary length, this check polls | |
* the hardware entropy source twice and compares the result to ensure they | |
* are not equal. | |
* - The error code returned by the entropy source is not an error. | |
*/ | |
int mbedtls_entropy_source_self_test( int verbose ) | |
{ | |
int ret = 0; | |
unsigned char buf0[2 * sizeof( unsigned long long int )]; | |
unsigned char buf1[2 * sizeof( unsigned long long int )]; | |
if( verbose != 0 ) | |
mbedtls_printf( " ENTROPY_BIAS test: " ); | |
memset( buf0, 0x00, sizeof( buf0 ) ); | |
memset( buf1, 0x00, sizeof( buf1 ) ); | |
if( ( ret = mbedtls_entropy_source_self_test_gather( buf0, sizeof( buf0 ) ) ) != 0 ) | |
goto cleanup; | |
if( ( ret = mbedtls_entropy_source_self_test_gather( buf1, sizeof( buf1 ) ) ) != 0 ) | |
goto cleanup; | |
/* Make sure that the returned values are not all 0 or 1 */ | |
if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf0, sizeof( buf0 ) ) ) != 0 ) | |
goto cleanup; | |
if( ( ret = mbedtls_entropy_source_self_test_check_bits( buf1, sizeof( buf1 ) ) ) != 0 ) | |
goto cleanup; | |
/* Make sure that the entropy source is not returning values in a | |
* pattern */ | |
ret = memcmp( buf0, buf1, sizeof( buf0 ) ) == 0; | |
cleanup: | |
if( verbose != 0 ) | |
{ | |
if( ret != 0 ) | |
mbedtls_printf( "failed\n" ); | |
else | |
mbedtls_printf( "passed\n" ); | |
mbedtls_printf( "\n" ); | |
} | |
return( ret != 0 ); | |
} | |
#endif /* MBEDTLS_ENTROPY_HARDWARE_ALT */ | |
/* | |
* 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 = 1; | |
#if !defined(MBEDTLS_TEST_NULL_ENTROPY) | |
mbedtls_entropy_context ctx; | |
unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 }; | |
unsigned char acc[MBEDTLS_ENTROPY_BLOCK_SIZE] = { 0 }; | |
size_t i, j; | |
#endif /* !MBEDTLS_TEST_NULL_ENTROPY */ | |
if( verbose != 0 ) | |
mbedtls_printf( " ENTROPY test: " ); | |
#if !defined(MBEDTLS_TEST_NULL_ENTROPY) | |
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; | |
} | |
} | |
#if defined(MBEDTLS_ENTROPY_HARDWARE_ALT) | |
if( ( ret = mbedtls_entropy_source_self_test( 0 ) ) != 0 ) | |
goto cleanup; | |
#endif | |
cleanup: | |
mbedtls_entropy_free( &ctx ); | |
#endif /* !MBEDTLS_TEST_NULL_ENTROPY */ | |
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 */ |