diff options
Diffstat (limited to 'lib/mbedtls-2.27.0/library/entropy.c')
| -rw-r--r-- | lib/mbedtls-2.27.0/library/entropy.c | 737 |
1 files changed, 737 insertions, 0 deletions
diff --git a/lib/mbedtls-2.27.0/library/entropy.c b/lib/mbedtls-2.27.0/library/entropy.c new file mode 100644 index 0000000..12fd3b9 --- /dev/null +++ b/lib/mbedtls-2.27.0/library/entropy.c @@ -0,0 +1,737 @@ +/* + * Entropy accumulator implementation + * + * Copyright The Mbed TLS Contributors + * 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. + */ + +#include "common.h" + +#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 "mbedtls/error.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 the context was already free, don't call free() again. + * This is important for mutexes which don't allow double-free. */ + if( ctx->accumulator_started == -1 ) + return; + +#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 = -1; +} + +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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + +#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 = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; + int i; + int 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + +#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, thresholds_reached; + size_t strong_size; + 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; + + thresholds_reached = 1; + strong_size = 0; + for( i = 0; i < ctx->source_count; i++ ) + { + if( ctx->source[i].size < ctx->source[i].threshold ) + thresholds_reached = 0; + if( ctx->source[i].strong == MBEDTLS_ENTROPY_SOURCE_STRONG ) + strong_size += ctx->source[i].size; + } + } + while( ! thresholds_reached || strong_size < MBEDTLS_ENTROPY_BLOCK_SIZE ); + + 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_ERROR_CORRUPTION_DETECTED; + FILE *f = NULL; + unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE]; + + if( ( ret = mbedtls_entropy_func( ctx, buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) ) != 0 ) + { + ret = MBEDTLS_ERR_ENTROPY_SOURCE_FAILED; + goto exit; + } + + if( ( f = fopen( path, "wb" ) ) == NULL ) + { + ret = MBEDTLS_ERR_ENTROPY_FILE_IO_ERROR; + 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 ) ); + + if( f != NULL ) + 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 */ |