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mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-07-29 11:41:15 +03:00

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>
This commit is contained in:
Gavin Acquroff
2020-03-01 17:06:11 -08:00
committed by gacquroff
parent 662deb38d6
commit 6aceb51e43
6 changed files with 54 additions and 21 deletions

View File

@ -240,6 +240,9 @@ void ctr_drbg_entropy_usage( int entropy_nonce_len )
if( entropy_nonce_len >= 0 )
TEST_ASSERT( mbedtls_ctr_drbg_set_nonce_len( &ctx, entropy_nonce_len ) == 0 );
/* Set reseed interval before seed */
mbedtls_ctr_drbg_set_reseed_interval( &ctx, 2 * reps );
/* Init must use entropy */
TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, mbedtls_test_entropy_func, entropy, NULL, 0 ) == 0 );
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
@ -249,8 +252,8 @@ void ctr_drbg_entropy_usage( int entropy_nonce_len )
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN;
TEST_EQUAL( test_offset_idx, expected_idx );
/* By default, PR is off and reseed_interval is large,
* so the next few calls should not use 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_ctr_drbg_random( &ctx, out, sizeof( out ) - 4 ) == 0 );
@ -265,15 +268,16 @@ void ctr_drbg_entropy_usage( int entropy_nonce_len )
TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
TEST_ASSERT( out[sizeof( out ) - 1] == 0 );
/* Set reseed_interval to the number of calls done,
* so the next call should reseed */
mbedtls_ctr_drbg_set_reseed_interval( &ctx, 2 * reps );
/* There have been 2 * reps calls to random. The next call should reseed */
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
expected_idx += MBEDTLS_CTR_DRBG_ENTROPY_LEN;
TEST_EQUAL( test_offset_idx, expected_idx );
/* The new few calls should not reseed */
for( i = 0; i < reps / 2; i++ )
/* Set reseed interval after seed */
mbedtls_ctr_drbg_set_reseed_interval( &ctx, 4 * reps + 1 );
/* The next few calls should not reseed */
for( i = 0; i < (2 * reps); i++ )
{
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) ,

View File

@ -57,6 +57,9 @@ void hmac_drbg_entropy_usage( int md_alg )
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 );
@ -64,8 +67,8 @@ void hmac_drbg_entropy_usage( int md_alg )
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 is large,
* so the next few calls should not use 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 );
@ -80,15 +83,16 @@ void hmac_drbg_entropy_usage( int md_alg )
TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
TEST_ASSERT( out[sizeof( out ) - 1] == 0 );
/* Set reseed_interval to the number of calls done,
* so the next call should reseed */
mbedtls_hmac_drbg_set_reseed_interval( &ctx, 2 * reps );
/* 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 < reps / 2; i++ )
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 ) ,
@ -199,7 +203,7 @@ void hmac_drbg_no_reseed( int md_alg, data_t * entropy,
TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, output->len,
add2->x, add2->len ) == 0 );
/* clear for second run */
/* Reset context for second run */
mbedtls_hmac_drbg_free( &ctx );
TEST_ASSERT( memcmp( my_output, output->x, output->len ) == 0 );