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>
diff --git a/tests/suites/test_suite_ctr_drbg.function b/tests/suites/test_suite_ctr_drbg.function
index 5e4cd26..c3ffe3b 100644
--- a/tests/suites/test_suite_ctr_drbg.function
+++ b/tests/suites/test_suite_ctr_drbg.function
@@ -240,6 +240,9 @@
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 @@
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 @@
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 ) ,