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/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
index 6c48ec1..7f1d232 100644
--- a/include/mbedtls/ctr_drbg.h
+++ b/include/mbedtls/ctr_drbg.h
@@ -210,6 +210,11 @@
* and prepares it for mbedtls_ctr_drbg_seed()
* or mbedtls_ctr_drbg_free().
*
+ * \note The reseed interval is
+ * #MBEDTLS_CTR_DRBG_RESEED_INTERVAL by default.
+ * You can override it by calling
+ * mbedtls_ctr_drbg_set_reseed_interval().
+ *
* \param ctx The CTR_DRBG context to initialize.
*/
void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx );
@@ -309,7 +314,8 @@
size_t len );
/**
- * \brief This function clears CTR_CRBG context data.
+ * \brief This function resets CTR_DRBG context to the state immediately
+ * after initial call of mbedtls_ctr_drbg_init().
*
* \param ctx The CTR_DRBG context to clear.
*/
diff --git a/include/mbedtls/hmac_drbg.h b/include/mbedtls/hmac_drbg.h
index 57ce9d9..9116541 100644
--- a/include/mbedtls/hmac_drbg.h
+++ b/include/mbedtls/hmac_drbg.h
@@ -111,6 +111,10 @@
* This function makes the context ready for mbedtls_hmac_drbg_seed(),
* mbedtls_hmac_drbg_seed_buf() or mbedtls_hmac_drbg_free().
*
+ * \note The reseed interval is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL
+ * by default. Override this value by calling
+ * mbedtls_hmac_drbg_set_reseed_interval().
+ *
* \param ctx HMAC_DRBG context to be initialized.
*/
void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx );
@@ -334,7 +338,8 @@
int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );
/**
- * \brief Free an HMAC_DRBG context
+ * \brief This function resets HMAC_DRBG context to the state immediately
+ * after initial call of mbedtls_hmac_drbg_init().
*
* \param ctx The HMAC_DRBG context to free.
*/