Allow maximum label length in Hkdf-Expand-Label
Previously, the length of the label was limited to the maximal length
that would be used in the TLS 1.3 key schedule. With the keying material
exporter, labels of up to 249 bytes may be used.
Signed-off-by: Max Fillinger <maximilian.fillinger@foxcrypto.com>
diff --git a/library/ssl_tls13_keys.h b/library/ssl_tls13_keys.h
index 31ffe44..14f6e48 100644
--- a/library/ssl_tls13_keys.h
+++ b/library/ssl_tls13_keys.h
@@ -60,8 +60,9 @@
mbedtls_ssl_tls13_labels.LABEL, \
MBEDTLS_SSL_TLS1_3_LBL_LEN(LABEL)
-#define MBEDTLS_SSL_TLS1_3_KEY_SCHEDULE_MAX_LABEL_LEN \
- sizeof(union mbedtls_ssl_tls13_labels_union)
+/* Maximum length of the label field in the HkdfLabel struct defined in
+ * RFC 8446, Section 7.1, excluding the "tls13 " prefix. */
+#define MBEDTLS_SSL_TLS1_3_HKDF_LABEL_MAX_LABEL_LEN 249
/* The maximum length of HKDF contexts used in the TLS 1.3 standard.
* Since contexts are always hashes of message transcripts, this can