Allow compile-time configuration of PRNG in SSL module
Introduces MBEDTLS_SSL_CONF_RNG to allow configuring the
RNG to be used by the SSL module at compile-time.
Impact on code-size:
| | GCC 8.2.1 | ARMC5 5.06 | ARMC6 6.12 |
| --- | --- | --- | --- |
| `libmbedtls.a` before | 23535 | 24089 | 27103 |
| `libmbedtls.a` after | 23471 | 24077 | 27045 |
| gain in Bytes | 64 | 12 | 58 |
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 95dd4cd..597f2a3 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -3601,6 +3601,13 @@
//#define MBEDTLS_SSL_CONF_CID_LEN 0
//#define MBEDTLS_SSL_CONF_IGNORE_UNEXPECTED_CID MBEDTLS_SSL_UNEXPECTED_CID_IGNORE
+/* The PRNG to use by the SSL module. If defined, this must
+ * evaluate to the name on externally defined function with signature
+ * int (*f_rng)(void *, unsigned char *, size_t),
+ * e.g. mbedtls_ctr_drbg_random or mbedtls_hmac_drbg_random.
+ */
+//#define MBEDTLS_SSL_CONF_RNG mbedtls_ctr_drbg_random
+
/* ExtendedMasterSecret extension
* The following two options must be set/unset simultaneously. */
//#define MBEDTLS_SSL_CONF_EXTENDED_MASTER_SECRET MBEDTLS_SSL_EXTENDED_MS_ENABLED