mbedtls/tests/suites/test_suite_hmac_drbg.function
Gavin Acquroff 6aceb51e43 Support set *_drbg reseed interval before seed
mbedtls_ctr_drbg_set_reseed_interval() and
mbedtls_hmac_drbg_set_reseed_interval() can now be called before
their seed functions and the reseed_interval value will persist.
Previously it would be overwritten with the default value.

*_drbg_reseed_interval is now set in init() and free().

mbedtls_ctr_drbg_free() and mbedtls_hmac_drbg_free() now
reset the drbg context to the state immediately after init().

Tests:
- Added test to check that DRBG reseeds when reseed_counter
reaches reseed_interval, if reseed_interval set before seed
and reseed_interval is less than MBEDTLS_CTR_DRBG_RESEED_INTERVAL.

Signed-off-by: gacquroff <gavina352@gmail.com>
2020-11-25 14:25:56 -08:00

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/* BEGIN_HEADER */
#include "mbedtls/hmac_drbg.h"
#include "string.h"
typedef struct
{
unsigned char *p;
size_t len;
} entropy_ctx;
static int mbedtls_test_entropy_func( void *data, unsigned char *buf, size_t len )
{
entropy_ctx *ctx = (entropy_ctx *) data;
if( len > ctx->len )
return( -1 );
memcpy( buf, ctx->p, len );
ctx->p += len;
ctx->len -= len;
return( 0 );
}
/* END_HEADER */
/* BEGIN_DEPENDENCIES
* depends_on:MBEDTLS_HMAC_DRBG_C
* END_DEPENDENCIES
*/
/* BEGIN_CASE */
void hmac_drbg_entropy_usage( int md_alg )
{
unsigned char out[16];
unsigned char buf[1024];
const mbedtls_md_info_t *md_info;
mbedtls_hmac_drbg_context ctx;
entropy_ctx entropy;
size_t i, reps = 10;
size_t default_entropy_len;
size_t expected_consumed_entropy = 0;
mbedtls_hmac_drbg_init( &ctx );
memset( buf, 0, sizeof( buf ) );
memset( out, 0, sizeof( out ) );
entropy.len = sizeof( buf );
entropy.p = buf;
md_info = mbedtls_md_info_from_type( md_alg );
TEST_ASSERT( md_info != NULL );
if( mbedtls_md_get_size( md_info ) <= 20 )
default_entropy_len = 16;
else if( mbedtls_md_get_size( md_info ) <= 28 )
default_entropy_len = 24;
else
default_entropy_len = 32;
/* Set reseed interval before seed */
mbedtls_hmac_drbg_set_reseed_interval( &ctx, 2 * reps );
/* Init must use entropy */
TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &entropy,
NULL, 0 ) == 0 );
/* default_entropy_len of entropy, plus half as much for the nonce */
expected_consumed_entropy += default_entropy_len * 3 / 2;
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
/* By default, PR is off, and reseed interval was set to
* 2 * reps so the next few calls should not use entropy */
for( i = 0; i < reps; i++ )
{
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) - 4 ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, out, sizeof( out ) - 4,
buf, 16 ) == 0 );
}
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
/* While at it, make sure we didn't write past the requested length */
TEST_ASSERT( out[sizeof( out ) - 4] == 0 );
TEST_ASSERT( out[sizeof( out ) - 3] == 0 );
TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
TEST_ASSERT( out[sizeof( out ) - 1] == 0 );
/* There have been 2 * reps calls to random. The next call should reseed */
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_consumed_entropy += default_entropy_len;
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
/* Set reseed interval after seed */
mbedtls_hmac_drbg_set_reseed_interval( &ctx, 4 * reps + 1);
/* The new few calls should not reseed */
for( i = 0; i < (2 * reps); i++ )
{
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, out, sizeof( out ) ,
buf, 16 ) == 0 );
}
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
/* Now enable PR, so the next few calls should all reseed */
mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_consumed_entropy += default_entropy_len;
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
/* Finally, check setting entropy_len */
mbedtls_hmac_drbg_set_entropy_len( &ctx, 42 );
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_consumed_entropy += 42;
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
mbedtls_hmac_drbg_set_entropy_len( &ctx, 13 );
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_consumed_entropy += 13;
TEST_EQUAL( sizeof( buf ) - entropy.len, expected_consumed_entropy );
exit:
mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_FS_IO */
void hmac_drbg_seed_file( int md_alg, char * path, int ret )
{
const mbedtls_md_info_t *md_info;
mbedtls_hmac_drbg_context ctx;
mbedtls_hmac_drbg_init( &ctx );
md_info = mbedtls_md_info_from_type( md_alg );
TEST_ASSERT( md_info != NULL );
TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info,
mbedtls_test_rnd_std_rand, NULL,
NULL, 0 ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_write_seed_file( &ctx, path ) == ret );
TEST_ASSERT( mbedtls_hmac_drbg_update_seed_file( &ctx, path ) == ret );
exit:
mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void hmac_drbg_buf( int md_alg )
{
unsigned char out[16];
unsigned char buf[100];
const mbedtls_md_info_t *md_info;
mbedtls_hmac_drbg_context ctx;
size_t i;
mbedtls_hmac_drbg_init( &ctx );
memset( buf, 0, sizeof( buf ) );
memset( out, 0, sizeof( out ) );
md_info = mbedtls_md_info_from_type( md_alg );
TEST_ASSERT( md_info != NULL );
TEST_ASSERT( mbedtls_hmac_drbg_seed_buf( &ctx, md_info, buf, sizeof( buf ) ) == 0 );
/* Make sure it never tries to reseed (would segfault otherwise) */
mbedtls_hmac_drbg_set_reseed_interval( &ctx, 3 );
mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );
for( i = 0; i < 30; i++ )
TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
exit:
mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void hmac_drbg_no_reseed( int md_alg, data_t * entropy,
data_t * custom, data_t * add1,
data_t * add2, data_t * output )
{
unsigned char data[1024];
unsigned char my_output[512];
entropy_ctx p_entropy;
const mbedtls_md_info_t *md_info;
mbedtls_hmac_drbg_context ctx;
mbedtls_hmac_drbg_init( &ctx );
p_entropy.p = entropy->x;
p_entropy.len = entropy->len;
md_info = mbedtls_md_info_from_type( md_alg );
TEST_ASSERT( md_info != NULL );
/* Test the simplified buffer-based variant */
memcpy( data, entropy->x, p_entropy.len );
memcpy( data + p_entropy.len, custom->x, custom->len );
TEST_ASSERT( mbedtls_hmac_drbg_seed_buf( &ctx, md_info,
data, p_entropy.len + custom->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add1->x, add1->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add2->x, add2->len ) == 0 );
/* Reset context for second run */
mbedtls_hmac_drbg_free( &ctx );
TEST_ASSERT( memcmp( my_output, output->x, output->len ) == 0 );
/* And now the normal entropy-based variant */
TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &p_entropy,
custom->x, custom->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add1->x, add1->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add2->x, add2->len ) == 0 );
TEST_ASSERT( memcmp( my_output, output->x, output->len ) == 0 );
exit:
mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void hmac_drbg_nopr( int md_alg, data_t * entropy, data_t * custom,
data_t * add1, data_t * add2, data_t * add3,
data_t * output )
{
unsigned char my_output[512];
entropy_ctx p_entropy;
const mbedtls_md_info_t *md_info;
mbedtls_hmac_drbg_context ctx;
mbedtls_hmac_drbg_init( &ctx );
p_entropy.p = entropy->x;
p_entropy.len = entropy->len;
md_info = mbedtls_md_info_from_type( md_alg );
TEST_ASSERT( md_info != NULL );
TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &p_entropy,
custom->x, custom->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_reseed( &ctx, add1->x, add1->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add2->x, add2->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add3->x, add3->len ) == 0 );
TEST_ASSERT( memcmp( my_output, output->x, output->len ) == 0 );
exit:
mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void hmac_drbg_pr( int md_alg, data_t * entropy, data_t * custom,
data_t * add1, data_t * add2, data_t * output )
{
unsigned char my_output[512];
entropy_ctx p_entropy;
const mbedtls_md_info_t *md_info;
mbedtls_hmac_drbg_context ctx;
mbedtls_hmac_drbg_init( &ctx );
p_entropy.p = entropy->x;
p_entropy.len = entropy->len;
md_info = mbedtls_md_info_from_type( md_alg );
TEST_ASSERT( md_info != NULL );
TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_test_entropy_func, &p_entropy,
custom->x, custom->len ) == 0 );
mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add1->x, add1->len ) == 0 );
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add2->x, add2->len ) == 0 );
TEST_ASSERT( memcmp( my_output, output->x, output->len ) == 0 );
exit:
mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SELF_TEST */
void hmac_drbg_selftest( )
{
TEST_ASSERT( mbedtls_hmac_drbg_self_test( 1 ) == 0 );
}
/* END_CASE */