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_*_DRBG_RESEED_INTERVAL.
Signed-off-by: gacquroff <gavina352@gmail.com>
diff --git a/library/hmac_drbg.c b/library/hmac_drbg.c
index f24a66c..26b15e9 100644
--- a/library/hmac_drbg.c
+++ b/library/hmac_drbg.c
@@ -87,6 +87,8 @@
{
memset( ctx, 0, sizeof( mbedtls_hmac_drbg_context ) );
+ ctx->reseed_interval = MBEDTLS_HMAC_DRBG_RESEED_INTERVAL;
+
#if defined(MBEDTLS_THREADING_C)
mbedtls_mutex_init( &ctx->mutex );
#endif
@@ -298,8 +300,6 @@
ctx->f_entropy = f_entropy;
ctx->p_entropy = p_entropy;
- ctx->reseed_interval = MBEDTLS_HMAC_DRBG_RESEED_INTERVAL;
-
if( ctx->entropy_len == 0 )
{
/*
@@ -444,7 +444,8 @@
}
/*
- * Free an HMAC_DRBG context
+ * This function resets HMAC_DRBG context to the state immediately
+ * after initial call of mbedtls_hmac_drbg_init().
*/
void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx )
{
@@ -456,6 +457,10 @@
#endif
mbedtls_md_free( &ctx->md_ctx );
mbedtls_zeroize( ctx, sizeof( mbedtls_hmac_drbg_context ) );
+ ctx->reseed_interval = MBEDTLS_HMAC_DRBG_RESEED_INTERVAL;
+#if defined(MBEDTLS_THREADING_C)
+ mbedtls_mutex_init( &ctx->mutex );
+#endif
}
#if defined(MBEDTLS_FS_IO)