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entropy_nv_seed: cope with SHA-256

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This test case was only executed if the SHA-512 module was enabled and
MBEDTLS_ENTROPY_FORCE_SHA256 was not enabled, so "config.pl full"
didn't have a chance to reach it even if that enabled
MBEDTLS_PLATFORM_NV_SEED_ALT.

Now all it takes to enable this test is MBEDTLS_PLATFORM_NV_SEED_ALT
and its requirements, and the near-ubiquitous MD module.
This commit is contained in:
Gilles Peskine 2019-06-12 19:33:42 +02:00
parent e39b903de5
commit 66afcca5a9
1 changed files with 37 additions and 22 deletions
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59
tests/suites/test_suite_entropy.function
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@ -301,10 +301,19 @@ void entropy_nv_seed_std_io( )
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_PLATFORM_NV_SEED_ALT:MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
/* BEGIN_CASE depends_on:MBEDTLS_MD_C:MBEDTLS_ENTROPY_NV_SEED:MBEDTLS_PLATFORM_NV_SEED_ALT */
void entropy_nv_seed( data_t * read_seed )
{
mbedtls_sha512_context accumulator;
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
const mbedtls_md_info_t *md_info =
mbedtls_md_info_from_type( MBEDTLS_MD_SHA512 );
#elif defined(MBEDTLS_ENTROPY_SHA256_ACCUMULATOR)
const mbedtls_md_info_t *md_info =
mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 );
#else
#error "Unsupported entropy accumulator"
#endif
mbedtls_md_context_t accumulator;
mbedtls_entropy_context ctx;
int (*original_mbedtls_nv_seed_read)( unsigned char *buf, size_t buf_len ) =
mbedtls_nv_seed_read;
@ -320,17 +329,14 @@ void entropy_nv_seed( data_t * read_seed )
memset( entropy, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
memset( buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
memset( buffer_seed, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
memset( empty, 0, MBEDTLS_ENTROPY_BLOCK_SIZE );
memset( check_seed, 2, MBEDTLS_ENTROPY_BLOCK_SIZE );
memset( check_entropy, 3, MBEDTLS_ENTROPY_BLOCK_SIZE );
// Set the initial NV seed to read
memcpy( buffer_seed, read_seed->x, read_seed->len );
// Make sure we read/write NV seed from our buffers
mbedtls_platform_set_nv_seed( buffer_nv_seed_read, buffer_nv_seed_write );
mbedtls_md_init( &accumulator );
mbedtls_entropy_init( &ctx );
entropy_clear_sources( &ctx );
@ -338,45 +344,54 @@ void entropy_nv_seed( data_t * read_seed )
MBEDTLS_ENTROPY_BLOCK_SIZE,
MBEDTLS_ENTROPY_SOURCE_STRONG ) == 0 );
// Set the initial NV seed to read
TEST_ASSERT( read_seed->len >= MBEDTLS_ENTROPY_BLOCK_SIZE );
memcpy( buffer_seed, read_seed->x, MBEDTLS_ENTROPY_BLOCK_SIZE );
// Do an entropy run
TEST_ASSERT( mbedtls_entropy_func( &ctx, entropy, sizeof( entropy ) ) == 0 );
// Determine what should have happened with manual entropy internal logic
// Only use the SHA-512 version to check
// Init accumulator
header[1] = MBEDTLS_ENTROPY_BLOCK_SIZE;
mbedtls_sha512_starts( &accumulator, 0 );
TEST_ASSERT( mbedtls_md_setup( &accumulator, md_info, 0 ) == 0 );
// First run for updating write_seed
header[0] = 0;
mbedtls_sha512_update( &accumulator, header, 2 );
mbedtls_sha512_update( &accumulator, read_seed->x, read_seed->len );
mbedtls_sha512_finish( &accumulator, buf );
TEST_ASSERT( mbedtls_md_starts( &accumulator ) == 0 );
TEST_ASSERT( mbedtls_md_update( &accumulator, header, 2 ) == 0 );
TEST_ASSERT( mbedtls_md_update( &accumulator,
read_seed->x, MBEDTLS_ENTROPY_BLOCK_SIZE ) == 0 );
TEST_ASSERT( mbedtls_md_finish( &accumulator, buf ) == 0 );
memset( &accumulator, 0, sizeof( mbedtls_sha512_context ) );
mbedtls_sha512_starts( &accumulator, 0 );
mbedtls_sha512_update( &accumulator, buf, MBEDTLS_ENTROPY_BLOCK_SIZE );
TEST_ASSERT( mbedtls_md_starts( &accumulator ) == 0 );
TEST_ASSERT( mbedtls_md_update( &accumulator,
buf, MBEDTLS_ENTROPY_BLOCK_SIZE ) == 0 );
mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, check_seed, 0 );
TEST_ASSERT( mbedtls_md( md_info, buf, MBEDTLS_ENTROPY_BLOCK_SIZE,
check_seed ) == 0 );
// Second run for actual entropy (triggers mbedtls_entropy_update_nv_seed)
header[0] = MBEDTLS_ENTROPY_SOURCE_MANUAL;
mbedtls_sha512_update( &accumulator, header, 2 );
mbedtls_sha512_update( &accumulator, empty, MBEDTLS_ENTROPY_BLOCK_SIZE );
TEST_ASSERT( mbedtls_md_update( &accumulator, header, 2 ) == 0 );
TEST_ASSERT( mbedtls_md_update( &accumulator,
empty, MBEDTLS_ENTROPY_BLOCK_SIZE ) == 0 );
header[0] = 0;
mbedtls_sha512_update( &accumulator, header, 2 );
mbedtls_sha512_update( &accumulator, check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE );
mbedtls_sha512_finish( &accumulator, buf );
TEST_ASSERT( mbedtls_md_update( &accumulator, header, 2 ) == 0 );
TEST_ASSERT( mbedtls_md_update( &accumulator,
check_seed, MBEDTLS_ENTROPY_BLOCK_SIZE ) == 0 );
TEST_ASSERT( mbedtls_md_finish( &accumulator, buf ) == 0 );
mbedtls_sha512( buf, MBEDTLS_ENTROPY_BLOCK_SIZE, check_entropy, 0 );
TEST_ASSERT( mbedtls_md( md_info, buf, MBEDTLS_ENTROPY_BLOCK_SIZE,
check_entropy ) == 0 );
// Check result of both NV file and entropy received with the manual calculations
TEST_ASSERT( memcmp( check_seed, buffer_seed, MBEDTLS_ENTROPY_BLOCK_SIZE ) == 0 );
TEST_ASSERT( memcmp( check_entropy, entropy, MBEDTLS_ENTROPY_BLOCK_SIZE ) == 0 );
exit:
mbedtls_md_free( &accumulator );
mbedtls_entropy_free( &ctx );
mbedtls_nv_seed_read = original_mbedtls_nv_seed_read;
mbedtls_nv_seed_write = original_mbedtls_nv_seed_write;