Introduce configuration option for TLS 1.3 padding granularity
TLS 1.3 record protection allows the addition of an arbitrary amount
of padding.
This commit introduces a configuration option
```
MBEDTLS_SSL_TLS13_PADDING_GRANULARITY
```
The semantics of this option is that padding is chosen in a minimal
way so that the padded plaintext has a length which is a multiple of
MBEDTLS_SSL_TLS13_PADDING_GRANULARITY.
For example, setting MBEDTLS_SSL_TLS13_PADDING_GRANULARITY to 1024
means that padded plaintexts will have length 1024, 2048, ..., while
setting it to 1 means that no padding will be used.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 5869e15..4a6ea6c 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -277,6 +277,10 @@
#define MBEDTLS_SSL_CID_PADDING_GRANULARITY 16
#endif
+#if !defined(MBEDTLS_SSL_TLS13_PADDING_GRANULARITY)
+#define MBEDTLS_SSL_TLS13_PADDING_GRANULARITY 16
+#endif
+
/* \} name SECTION: Module settings */
/*