1 files changed, 147 insertions, 0 deletions
diff --git a/lib/ext/early_data.c b/lib/ext/early_data.c
new file mode 100644
index 0000000..28c3182
--- /dev/null
+++ b/lib/ext/early_data.c
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2018 Red Hat, Inc.
+ *
+ * Author: Daiki Ueno
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>
+ *
+ */
+
+/* This file contains the code for the Early Data TLS 1.3 extension.
+ */
+
+#include "gnutls_int.h"
+#include "errors.h"
+#include "num.h"
+#include "hello_ext_lib.h"
+#include <ext/early_data.h>
+
+static int early_data_recv_params(gnutls_session_t session,
+				  const uint8_t * data,
+				  size_t data_size);
+static int early_data_send_params(gnutls_session_t session,
+				  gnutls_buffer_st * extdata);
+
+const hello_ext_entry_st ext_mod_early_data = {
+	.name = "Early Data",
+	.tls_id = 42,
+	.gid = GNUTLS_EXTENSION_EARLY_DATA,
+	.validity = GNUTLS_EXT_FLAG_TLS | GNUTLS_EXT_FLAG_CLIENT_HELLO | GNUTLS_EXT_FLAG_EE,
+	.client_parse_point = GNUTLS_EXT_MANDATORY, /* force parsing prior to EXT_TLS extensions */
+	.server_parse_point = GNUTLS_EXT_MANDATORY, /* force parsing prior to EXT_TLS extensions */
+	.recv_func = early_data_recv_params,
+	.send_func = early_data_send_params,
+	.pack_func = NULL,
+	.unpack_func = NULL,
+	.deinit_func = _gnutls_hello_ext_default_deinit,
+	.cannot_be_overriden = 0
+};
+
+static int
+early_data_recv_params(gnutls_session_t session,
+		       const uint8_t * data, size_t _data_size)
+{
+	const version_entry_st *vers = get_version(session);
+
+	if (!vers || !vers->tls13_sem)
+		return gnutls_assert_val(0);
+
+	if (session->security_parameters.entity == GNUTLS_SERVER) {
+		/* Whether to accept early data is decided during processing the
+		 * pre_shared_key extension in the later phase.
+		 */
+		session->internals.hsk_flags |= HSK_EARLY_DATA_IN_FLIGHT;
+	} else {
+		if (_gnutls_ext_get_msg(session) == GNUTLS_EXT_FLAG_EE)
+			session->internals.hsk_flags |= HSK_EARLY_DATA_ACCEPTED;
+	}
+
+	return 0;
+}
+
+/* returns data_size or a negative number on failure
+ */
+static int
+early_data_send_params(gnutls_session_t session,
+		       gnutls_buffer_st * extdata)
+{
+	if (session->security_parameters.entity == GNUTLS_SERVER) {
+		if (session->internals.hsk_flags & HSK_EARLY_DATA_ACCEPTED)
+			return GNUTLS_E_INT_RET_0;
+	} else {
+		/* early data is enabled and resuming a TLS 1.3 session */
+		if (session->internals.flags & GNUTLS_ENABLE_EARLY_DATA &&
+		    !(session->internals.resumption_requested == 0 &&
+		      session->internals.premaster_set == 0) &&
+		    session->internals.resumed_security_parameters.pversion &&
+		    session->internals.resumed_security_parameters.pversion->tls13_sem) {
+			session->internals.hsk_flags |= HSK_EARLY_DATA_IN_FLIGHT;
+			return GNUTLS_E_INT_RET_0;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * gnutls_record_get_max_early_data_size:
+ * @session: is a #gnutls_session_t type.
+ *
+ * This function returns the maximum early data size in this connection.
+ * This property can only be set to servers.  The client may be
+ * provided with the maximum allowed size through the "early_data"
+ * extension of the NewSessionTicket handshake message.
+ *
+ * Returns: The maximum early data size in this connection.
+ *
+ * Since: 3.6.5
+ **/
+size_t
+gnutls_record_get_max_early_data_size(gnutls_session_t session)
+{
+	return session->security_parameters.max_early_data_size;
+}
+
+/**
+ * gnutls_record_set_max_early_data_size:
+ * @session: is a #gnutls_session_t type.
+ * @size: is the new size
+ *
+ * This function sets the maximum early data size in this connection.
+ * This property can only be set to servers.  The client may be
+ * provided with the maximum allowed size through the "early_data"
+ * extension of the NewSessionTicket handshake message.
+ *
+ * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned,
+ *   otherwise a negative error code is returned.
+ *
+ * Since: 3.6.4
+ **/
+int
+gnutls_record_set_max_early_data_size(gnutls_session_t session,
+				      size_t size)
+{
+	if (session->security_parameters.entity == GNUTLS_CLIENT)
+		return GNUTLS_E_INVALID_REQUEST;
+
+	/* Reject zero as well, as it is useless. */
+	if (size == 0 || size > UINT32_MAX)
+		return GNUTLS_E_INVALID_REQUEST;
+
+	session->security_parameters.max_early_data_size = (uint32_t) size;
+
+	return 0;
+}