_tls13_derive_secret: define secret argument

TLS 1.3 exporters need to derive a secret from exporter_master_secret
or early_exporter_master_secret, not the handshake or application
secret stored in temp_secret.  Add a new argument @secret to
_tls13_derive_secret to specify any secret.

Signed-off-by: Daiki Ueno <dueno@redhat.com>

1 files changed, 5 insertions, 18 deletions

diff --git a/lib/secrets.c b/lib/secrets.c
index 2f0750dc92..1042fba2c5 100644
--- a/lib/secrets.c
+++ b/lib/secrets.c
@@ -61,12 +61,11 @@ int _tls13_update_secret(gnutls_session_t session, const uint8_t *key, size_t ke
 				session->key.temp_secret);
 }
 
-static
-int _tls13_expand_hash_secret(gnutls_session_t session,
+/* Derive-Secret(Secret, Label, Messages) */
+int _tls13_derive_secret(gnutls_session_t session,
 			 const char *label, unsigned label_size,
 			 const uint8_t *tbh, size_t tbh_size,
-			 const uint8_t secret[MAX_CIPHER_KEY_SIZE],
-			 unsigned out_size,
+			 const uint8_t secret[MAX_HASH_SIZE],
 			 void *out)
 {
 	uint8_t digest[MAX_HASH_SIZE];
@@ -81,14 +80,14 @@ int _tls13_expand_hash_secret(gnutls_session_t session,
 	if (ret < 0)
 		return gnutls_assert_val(ret);
 
-	return _tls13_expand_secret(session, label, label_size, digest, digest_size, secret, out_size, out);
+	return _tls13_expand_secret(session, label, label_size, digest, digest_size, secret, digest_size, out);
 }
 
 /* HKDF-Expand-Label(Secret, Label, HashValue, Length) */
 int _tls13_expand_secret(gnutls_session_t session,
 			 const char *label, unsigned label_size,
 			 const uint8_t *msg, size_t msg_size,
-			 const uint8_t secret[MAX_CIPHER_KEY_SIZE],
+			 const uint8_t secret[MAX_HASH_SIZE],
 			 unsigned out_size,
 			 void *out)
 {
@@ -161,15 +160,3 @@ int _tls13_expand_secret(gnutls_session_t session,
 	_gnutls_buffer_clear(&str);
 	return ret;
 }
-
-/* Derive-Secret(Secret, Label, Messages) */
-int _tls13_derive_secret(gnutls_session_t session,
-			 const char *label, unsigned label_size,
-			 const uint8_t *msg, size_t msg_size,
-			 void *out)
-{
-	return _tls13_expand_hash_secret(session, label, label_size, msg, msg_size,
-				         session->key.temp_secret,
-				         session->key.temp_secret_size,
-				         out);
-}