--- /dev/null
+/* packet-wireguard.c
+ * Routines for WireGuard dissection
+ * Copyright 2018, Peter Wu <peter@lekensteyn.nl>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+/*
+ * Protocol details: https://www.wireguard.com/protocol/
+ */
+
+#include <config.h>
+
+#include <epan/packet.h>
+#include <epan/expert.h>
+#include <epan/prefs.h>
+
+void proto_reg_handoff_wg(void);
+void proto_register_wg(void);
+
+static int proto_wg = -1;
+static int hf_wg_type = -1;
+static int hf_wg_reserved = -1;
+static int hf_wg_sender = -1;
+static int hf_wg_ephemeral = -1;
+static int hf_wg_encrypted_static = -1;
+static int hf_wg_encrypted_timestamp = -1;
+static int hf_wg_mac1 = -1;
+static int hf_wg_mac2 = -1;
+static int hf_wg_receiver = -1;
+static int hf_wg_encrypted_empty = -1;
+static int hf_wg_nonce = -1;
+static int hf_wg_encrypted_cookie = -1;
+static int hf_wg_counter = -1;
+static int hf_wg_encrypted_packet = -1;
+
+static gint ett_wg = -1;
+
+static expert_field ei_wg_bad_packet_length = EI_INIT;
+static expert_field ei_wg_keepalive = EI_INIT;
+
+
+// Length of AEAD authentication tag
+#define AUTH_TAG_LENGTH 16
+
+typedef enum {
+ WG_TYPE_HANDSHAKE_INITIATION = 1,
+ WG_TYPE_HANDSHAKE_RESPONSE = 2,
+ WG_TYPE_COOKIE_REPLY = 3,
+ WG_TYPE_TRANSPORT_DATA = 4
+} wg_message_type;
+
+static const value_string wg_type_names[] = {
+ { 0x01, "Handshake Initiation" },
+ { 0x02, "Handshake Response" },
+ { 0x03, "Cookie Reply" },
+ { 0x04, "Transport Data" },
+ { 0x00, NULL }
+};
+
+static void
+wg_dissect_pubkey(proto_tree *tree, tvbuff_t *tvb, int offset, gboolean is_ephemeral)
+{
+ const guint8 *pubkey = tvb_get_ptr(tvb, offset, 32);
+ gchar *str = g_base64_encode(pubkey, 32);
+ gchar *key_str = wmem_strdup(wmem_packet_scope(), str);
+ g_free(str);
+
+ int hf_id = is_ephemeral ? hf_wg_ephemeral : -1; // TODO extend for static keys
+ proto_tree_add_string(tree, hf_id, tvb, offset, 32, key_str);
+}
+
+static int
+wg_dissect_handshake_initiation(tvbuff_t *tvb, packet_info *pinfo, proto_tree *wg_tree)
+{
+ guint32 sender_id;
+
+ proto_tree_add_item_ret_uint(wg_tree, hf_wg_sender, tvb, 4, 4, ENC_LITTLE_ENDIAN, &sender_id);
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", sender=0x%08X", sender_id);
+ wg_dissect_pubkey(wg_tree, tvb, 8, TRUE);
+ proto_tree_add_item(wg_tree, hf_wg_encrypted_static, tvb, 40, 32 + AUTH_TAG_LENGTH, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_encrypted_timestamp, tvb, 88, 12 + AUTH_TAG_LENGTH, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_mac1, tvb, 116, 16, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_mac2, tvb, 132, 16, ENC_NA);
+
+ return 148;
+}
+
+static int
+wg_dissect_handshake_response(tvbuff_t *tvb, packet_info *pinfo, proto_tree *wg_tree)
+{
+ guint32 sender_id, receiver_id;
+
+ proto_tree_add_item_ret_uint(wg_tree, hf_wg_sender, tvb, 4, 4, ENC_LITTLE_ENDIAN, &sender_id);
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", sender=0x%08X", sender_id);
+ proto_tree_add_item_ret_uint(wg_tree, hf_wg_receiver, tvb, 8, 4, ENC_LITTLE_ENDIAN, &receiver_id);
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", receiver=0x%08X", receiver_id);
+ wg_dissect_pubkey(wg_tree, tvb, 12, TRUE);
+ proto_tree_add_item(wg_tree, hf_wg_encrypted_empty, tvb, 44, 16, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_mac1, tvb, 60, 16, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_mac2, tvb, 76, 16, ENC_NA);
+
+ return 92;
+}
+
+static int
+wg_dissect_handshake_cookie(tvbuff_t *tvb, packet_info *pinfo, proto_tree *wg_tree)
+{
+ guint32 receiver_id;
+
+ proto_tree_add_item_ret_uint(wg_tree, hf_wg_receiver, tvb, 4, 4, ENC_LITTLE_ENDIAN, &receiver_id);
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", receiver=0x%08X", receiver_id);
+ proto_tree_add_item(wg_tree, hf_wg_nonce, tvb, 8, 24, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_encrypted_cookie, tvb, 32, 16 + AUTH_TAG_LENGTH, ENC_NA);
+
+ return 64;
+}
+
+static int
+wg_dissect_data(tvbuff_t *tvb, packet_info *pinfo, proto_tree *wg_tree)
+{
+ guint32 receiver_id;
+ guint64 counter;
+ proto_item *ti;
+
+ proto_tree_add_item_ret_uint(wg_tree, hf_wg_receiver, tvb, 4, 4, ENC_LITTLE_ENDIAN, &receiver_id);
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", receiver=0x%08X", receiver_id);
+ proto_tree_add_item_ret_uint64(wg_tree, hf_wg_counter, tvb, 8, 8, ENC_LITTLE_ENDIAN, &counter);
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", counter=%" G_GUINT64_FORMAT, counter);
+
+ gint packet_length = tvb_captured_length_remaining(tvb, 16);
+ if (packet_length < AUTH_TAG_LENGTH) {
+ proto_tree_add_expert(wg_tree, pinfo, &ei_wg_bad_packet_length, tvb, 16, packet_length);
+ return 16 + packet_length;
+ } else if (packet_length != AUTH_TAG_LENGTH) {
+ /* Keepalive messages are already marked, no need to append data length. */
+ col_append_fstr(pinfo->cinfo, COL_INFO, ", datalen=%d", packet_length - AUTH_TAG_LENGTH);
+ }
+ ti = proto_tree_add_item(wg_tree, hf_wg_encrypted_packet, tvb, 16, packet_length, ENC_NA);
+
+ if (packet_length == AUTH_TAG_LENGTH) {
+ expert_add_info(pinfo, ti, &ei_wg_keepalive);
+ }
+
+ return 16 + packet_length;
+}
+
+static int
+dissect_wg(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
+{
+ proto_item *ti;
+ proto_tree *wg_tree;
+ guint32 message_type;
+ const char *message_type_str;
+
+ /* Heuristics check: check for reserved bits (zeros) and message type. */
+ if (tvb_reported_length(tvb) < 4 || tvb_get_ntoh24(tvb, 1) != 0)
+ return 0;
+
+ message_type = tvb_get_guint8(tvb, 0);
+ message_type_str = try_val_to_str(message_type, wg_type_names);
+ if (!message_type_str)
+ return 0;
+
+ /* Special case: zero-length data message is a Keepalive message. */
+ if (message_type == WG_TYPE_TRANSPORT_DATA && tvb_reported_length(tvb) == 32) {
+ message_type_str = "Keepalive";
+ }
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "WireGuard");
+ col_set_str(pinfo->cinfo, COL_INFO, message_type_str);
+
+ ti = proto_tree_add_item(tree, proto_wg, tvb, 0, -1, ENC_NA);
+ wg_tree = proto_item_add_subtree(ti, ett_wg);
+
+ proto_tree_add_item(wg_tree, hf_wg_type, tvb, 0, 1, ENC_NA);
+ proto_tree_add_item(wg_tree, hf_wg_reserved, tvb, 1, 3, ENC_NA);
+
+ switch ((wg_message_type)message_type) {
+ case WG_TYPE_HANDSHAKE_INITIATION:
+ return wg_dissect_handshake_initiation(tvb, pinfo, wg_tree);
+ case WG_TYPE_HANDSHAKE_RESPONSE:
+ return wg_dissect_handshake_response(tvb, pinfo, wg_tree);
+ case WG_TYPE_COOKIE_REPLY:
+ return wg_dissect_handshake_cookie(tvb, pinfo, wg_tree);
+ case WG_TYPE_TRANSPORT_DATA:
+ return wg_dissect_data(tvb, pinfo, wg_tree);
+ }
+
+ DISSECTOR_ASSERT_NOT_REACHED();
+}
+
+void
+proto_register_wg(void)
+{
+ expert_module_t *expert_wg;
+
+ static hf_register_info hf[] = {
+ /* Initiation message */
+ { &hf_wg_type,
+ { "Type", "wg.type",
+ FT_UINT8, BASE_DEC, VALS(wg_type_names), 0x0,
+ NULL, HFILL }
+ },
+ { &hf_wg_reserved,
+ { "Reserved", "wg.reserved",
+ FT_NONE, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+ { &hf_wg_sender,
+ { "Sender", "wg.sender",
+ FT_UINT32, BASE_HEX, NULL, 0x0,
+ "Identifier as chosen by the sender", HFILL }
+ },
+ { &hf_wg_ephemeral,
+ { "Ephemeral", "wg.ephemeral",
+ FT_STRING, BASE_NONE, NULL, 0x0,
+ "Ephemeral public key of sender", HFILL }
+ },
+ { &hf_wg_encrypted_static,
+ { "Encrypted Static", "wg.encrypted_static",
+ FT_NONE, BASE_NONE, NULL, 0x0,
+ "Encrypted long-term static public key of sender", HFILL }
+ },
+ { &hf_wg_encrypted_timestamp,
+ { "Encrypted Timestamp", "wg.encrypted_timestamp",
+ FT_NONE, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+ { &hf_wg_mac1,
+ { "mac1", "wg.mac1",
+ FT_BYTES, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+ { &hf_wg_mac2,
+ { "mac2", "wg.mac2",
+ FT_BYTES, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+
+ /* Response message */
+ { &hf_wg_receiver,
+ { "Receiver", "wg.receiver",
+ FT_UINT32, BASE_HEX, NULL, 0x0,
+ "Identifier as chosen by receiver", HFILL }
+ },
+ { &hf_wg_encrypted_empty,
+ { "Encrypted Empty", "wg.encrypted_empty",
+ FT_NONE, BASE_NONE, NULL, 0x0,
+ "Authenticated encryption of an empty string", HFILL }
+ },
+
+ /* Cookie message */
+ { &hf_wg_nonce,
+ { "Nonce", "wg.nonce",
+ FT_BYTES, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+ { &hf_wg_encrypted_cookie,
+ { "Encrypted Cookie", "wg.encrypted_cookie",
+ FT_BYTES, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+ /* TODO decrypted cookie field. */
+
+ /* Data message */
+ { &hf_wg_counter,
+ { "Counter", "wg.counter",
+ FT_UINT64, BASE_DEC, NULL, 0x0,
+ NULL, HFILL }
+ },
+ { &hf_wg_encrypted_packet,
+ { "Encrypted Packet", "wg.encrypted_packet",
+ FT_NONE, BASE_NONE, NULL, 0x0,
+ NULL, HFILL }
+ },
+ };
+
+ static gint *ett[] = {
+ &ett_wg,
+ };
+
+ static ei_register_info ei[] = {
+ { &ei_wg_bad_packet_length,
+ { "wg.bad_packet_length", PI_MALFORMED, PI_ERROR,
+ "Packet length is too small", EXPFILL }
+ },
+ { &ei_wg_keepalive,
+ { "wg.keepalive", PI_SEQUENCE, PI_CHAT,
+ "This is a Keepalive message", EXPFILL }
+ },
+ };
+
+ proto_wg = proto_register_protocol("WireGuard Protocol", "WireGuard", "wg");
+
+ proto_register_field_array(proto_wg, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+
+ expert_wg = expert_register_protocol(proto_wg);
+ expert_register_field_array(expert_wg, ei, array_length(ei));
+
+ register_dissector("wg", dissect_wg, proto_wg);
+}
+
+void
+proto_reg_handoff_wg(void)
+{
+ heur_dissector_add("udp", dissect_wg, "WireGuard", "wg", proto_wg, HEURISTIC_ENABLE);
+}
+
+/*
+ * Editor modelines - https://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */
git.samba.org / metze / wireshark / wip.git / commitdiff