Add tests with a fake entropy source

Add tests with a fake entropy source to check that the required amount
of entropy is one block, fed in one or more steps.
This commit is contained in:
Gilles Peskine 2018-11-20 22:41:50 +01:00
parent 5e76952235
commit ebe770c693
2 changed files with 93 additions and 4 deletions

View File

@ -24,3 +24,18 @@ custom_entropy_sources:0x0000ffff:PSA_SUCCESS
Custom entropy sources: none
custom_entropy_sources:0:PSA_ERROR_INSUFFICIENT_ENTROPY
Fake entropy: never returns anything
fake_entropy_source:MBEDTLS_ENTROPY_BLOCK_SIZE:0:0:0:0:PSA_ERROR_INSUFFICIENT_ENTROPY
Fake entropy: less than the block size
fake_entropy_source:MBEDTLS_ENTROPY_BLOCK_SIZE:MBEDTLS_ENTROPY_BLOCK_SIZE - 1:-1:-1:-1:PSA_ERROR_INSUFFICIENT_ENTROPY
Fake entropy: one block eventually
fake_entropy_source:MBEDTLS_ENTROPY_BLOCK_SIZE:0:0:0:MBEDTLS_ENTROPY_BLOCK_SIZE:PSA_SUCCESS
Fake entropy: one block in two steps
fake_entropy_source:MBEDTLS_ENTROPY_BLOCK_SIZE:MBEDTLS_ENTROPY_BLOCK_SIZE - 1:1:-1:-1:PSA_SUCCESS
Fake entropy: more than one block in two steps
fake_entropy_source:MBEDTLS_ENTROPY_BLOCK_SIZE:MBEDTLS_ENTROPY_BLOCK_SIZE - 1:MBEDTLS_ENTROPY_BLOCK_SIZE - 1:-1:-1:PSA_SUCCESS

View File

@ -12,12 +12,41 @@
#include "mbedtls/entropy.h"
#include "mbedtls/entropy_poll.h"
#define MIN( x, y ) ( ( x ) < ( y ) ? ( x ) : ( y ) )
typedef struct
{
size_t threshold; /* Minimum bytes to make mbedtls_entropy_func happy */
size_t max_steps;
size_t *length_sequence;
size_t step;
} fake_entropy_state_t;
static int fake_entropy_source( void *state_arg,
unsigned char *output, size_t len,
size_t *olen )
{
fake_entropy_state_t *state = state_arg;
size_t i;
if( state->step >= state->max_steps )
return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
*olen = MIN( len, state->length_sequence[state->step] );
for( i = 0; i < *olen; i++ )
output[i] = i;
++state->step;
return( 0 );
};
#define ENTROPY_SOURCE_PLATFORM 0x00000001
#define ENTROPY_SOURCE_TIMING 0x00000002
#define ENTROPY_SOURCE_HAVEGE 0x00000004
#define ENTROPY_SOURCE_HARDWARE 0x00000008
#define ENTROPY_SOURCE_NV_SEED 0x00000010
#define ENTROPY_SOURCE_FAKE 0x40000000
static uint32_t custom_entropy_sources_mask;
static fake_entropy_state_t fake_entropy_state;
/* This is a modified version of mbedtls_entropy_init() from entropy.c
* which chooses entropy sources dynamically. */
@ -71,6 +100,12 @@ static void custom_entropy_init( mbedtls_entropy_context *ctx )
MBEDTLS_ENTROPY_SOURCE_STRONG );
ctx->initial_entropy_run = 0;
#endif
if( custom_entropy_sources_mask & ENTROPY_SOURCE_FAKE )
mbedtls_entropy_add_source( ctx,
fake_entropy_source, &fake_entropy_state,
fake_entropy_state.threshold,
MBEDTLS_ENTROPY_SOURCE_STRONG );
}
/* END_HEADER */
@ -147,7 +182,6 @@ void validate_module_init_key_based( int count )
void custom_entropy_sources( int sources_arg, int expected_init_status_arg )
{
psa_status_t expected_init_status = expected_init_status_arg;
int inited = 0;
uint8_t random[10] = { 0 };
custom_entropy_sources_mask = sources_arg;
@ -158,13 +192,53 @@ void custom_entropy_sources( int sources_arg, int expected_init_status_arg )
TEST_ASSERT( psa_crypto_init( ) == expected_init_status );
if( expected_init_status != PSA_SUCCESS )
goto exit;
inited = 1;
TEST_ASSERT( psa_generate_random( random, sizeof( random ) ) ==
PSA_SUCCESS );
exit:
if( inited )
mbedtls_psa_crypto_free( );
mbedtls_psa_crypto_free( );
}
/* END_CASE */
/* BEGIN_CASE */
void fake_entropy_source( int threshold,
int amount1,
int amount2,
int amount3,
int amount4,
int expected_init_status_arg )
{
psa_status_t expected_init_status = expected_init_status_arg;
uint8_t random[10] = { 0 };
size_t lengths[4];
fake_entropy_state.threshold = threshold;
fake_entropy_state.step = 0;
fake_entropy_state.max_steps = 0;
if( amount1 >= 0 )
lengths[fake_entropy_state.max_steps++] = amount1;
if( amount2 >= 0 )
lengths[fake_entropy_state.max_steps++] = amount2;
if( amount3 >= 0 )
lengths[fake_entropy_state.max_steps++] = amount3;
if( amount4 >= 0 )
lengths[fake_entropy_state.max_steps++] = amount4;
fake_entropy_state.length_sequence = lengths;
custom_entropy_sources_mask = ENTROPY_SOURCE_FAKE;
TEST_ASSERT( mbedtls_psa_crypto_configure_entropy_sources(
custom_entropy_init, mbedtls_entropy_free ) ==
PSA_SUCCESS );
TEST_ASSERT( psa_crypto_init( ) == expected_init_status );
if( expected_init_status != PSA_SUCCESS )
goto exit;
TEST_ASSERT( psa_generate_random( random, sizeof( random ) ) ==
PSA_SUCCESS );
exit:
mbedtls_psa_crypto_free( );
}
/* END_CASE */