mbedtls_ctr_drbg_update_ret: correct doc for input length limit
Unlike mbedtls_ctr_drbg_update, this function returns an error if the
length limit is exceeded, rather than silently truncating the input.
diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
index 9a3aba0..10f9389 100644
--- a/include/mbedtls/ctr_drbg.h
+++ b/include/mbedtls/ctr_drbg.h
@@ -239,16 +239,15 @@
/**
* \brief This function updates the state of the CTR_DRBG context.
*
- * \note If \p add_len is greater than
- * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT, only the first
- * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT Bytes are used.
- * The remaining Bytes are silently discarded.
- *
* \param ctx The CTR_DRBG context.
* \param additional The data to update the state with.
- * \param add_len Length of \p additional data.
+ * \param add_len Length of \p additional in bytes. This must be at
+ * most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
*
* \return \c 0 on success.
+ * \return #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if
+ * \p add_len is more than
+ * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
* \return An error from the underlying AES cipher on failure.
*/
int mbedtls_ctr_drbg_update_ret( mbedtls_ctr_drbg_context *ctx,