Added support for the extended master secret calculation

That is performed implicitly unless GNUTLS_NO_EXTENSIONS is specified.
The implementation follows draft-ietf-tls-session-hash-02.

1 files changed, 66 insertions, 0 deletions

diff --git a/lib/gnutls_handshake.c b/lib/gnutls_handshake.c
index 28e4a7eafe..9ddcfbce3e 100644
--- a/lib/gnutls_handshake.c
+++ b/lib/gnutls_handshake.c
@@ -3571,3 +3571,69 @@ gnutls_handshake_get_last_out(gnutls_session_t session)
 {
 	return session->internals.last_handshake_out;
 }
+
+/* This returns the session hash as in draft-ietf-tls-session-hash-02.
+ *
+ * FIXME: It duplicates some of the actions in _gnutls_handshake_sign_crt_vrfy*.
+ * See whether they can be merged.
+ */
+int _gnutls_handshake_get_session_hash(gnutls_session_t session, gnutls_datum_t *shash)
+{
+	const version_entry_st *ver = get_version(session);
+	int ret;
+	const mac_entry_st *me;
+	uint8_t concat[2*MAX_HASH_SIZE];
+	digest_hd_st td_md5;
+	digest_hd_st td_sha;
+
+	if (unlikely(ver == NULL))
+		return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
+
+	if (_gnutls_version_has_selectable_prf(ver)) { /* TLS 1.2+ */
+		gnutls_mac_algorithm_t prf;
+
+		prf = _gnutls_cipher_suite_get_prf(session->security_parameters.cipher_suite);
+		if (prf == GNUTLS_MAC_UNKNOWN)
+			return gnutls_assert_val(GNUTLS_E_UNKNOWN_PK_ALGORITHM);
+
+		me = mac_to_entry(prf);
+
+		ret =
+		    _gnutls_hash_fast((gnutls_digest_algorithm_t)me->id,
+				      session->internals.handshake_hash_buffer.
+				      data,
+				      session->internals.handshake_hash_buffer.
+				      length, concat);
+		if (ret < 0)
+			return gnutls_assert_val(ret);
+
+		return _gnutls_set_datum(shash, concat, me->output_size);
+	} else {
+		ret = _gnutls_hash_init(&td_sha, hash_to_entry(GNUTLS_DIG_SHA1));
+		if (ret < 0) {
+			gnutls_assert();
+			return ret;
+		}
+
+		_gnutls_hash(&td_sha,
+			     session->internals.handshake_hash_buffer.data,
+			     session->internals.handshake_hash_buffer.length);
+
+		_gnutls_hash_deinit(&td_sha, &concat[16]);
+
+		ret =
+		    _gnutls_hash_init(&td_md5,
+				      hash_to_entry(GNUTLS_DIG_MD5));
+		if (ret < 0)
+			return gnutls_assert_val(ret);
+
+		_gnutls_hash(&td_md5,
+			     session->internals.handshake_hash_buffer.data,
+			     session->internals.handshake_hash_buffer.
+			     length);
+
+		_gnutls_hash_deinit(&td_md5, concat);
+
+		return _gnutls_set_datum(shash, concat, 36);
+	}
+}