Remove duplicated computation of TLS 1.3 HKDF label length
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/ssl_tls13_keys.c b/library/ssl_tls13_keys.c
index c985aaf..a899b7b 100644
--- a/library/ssl_tls13_keys.c
+++ b/library/ssl_tls13_keys.c
@@ -73,12 +73,17 @@
* the HkdfLabel structure on success.
*/
-#define SSL_TLS1_3_KEY_SCHEDULE_MAX_HKDF_LABEL_LEN \
+#define SSL_TLS1_3_KEY_SCHEDULE_HKDF_LABEL_LEN( label_len, context_len ) \
( 2 /* expansion length */ \
+ 1 /* label length */ \
- + MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_LABEL_LEN \
+ + label_len \
+ 1 /* context length */ \
- + MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_CONTEXT_LEN )
+ + context_len )
+
+#define SSL_TLS1_3_KEY_SCHEDULE_MAX_HKDF_LABEL_LEN \
+ SSL_TLS1_3_KEY_SCHEDULE_HKDF_LABEL_LEN( \
+ MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_LABEL_LEN, \
+ MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_CONTEXT_LEN )
static void ssl_tls1_3_hkdf_encode_label(
size_t desired_length,
@@ -89,11 +94,7 @@
const char label_prefix[6] = { 't', 'l', 's', '1', '3', ' ' };
size_t total_label_len = sizeof( label_prefix ) + llen;
size_t total_hkdf_lbl_len =
- 2 /* length of expanded key material */
- + 1 /* label length */
- + total_label_len /* actual label, incl. prefix */
- + 1 /* context length */
- + clen; /* actual context */
+ SSL_TLS1_3_KEY_SCHEDULE_HKDF_LABEL_LEN( total_label_len, clen );
unsigned char *p = dst;