/* packet-ms-nns.c * Routines for .NET NegotiateStream Protocol (MS-NNS) dissection * Copyright 2020, Uli Heilmeier * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ /* * Basic dissector for .NET NegotiateStream Protocol based on protocol reference found at * https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-NNS/%5bMS-NNS%5d.pdf */ #include #include #include /* Prototypes */ void proto_reg_handoff_nns(void); void proto_register_nns(void); static dissector_handle_t gssapi_handle; #define MS_NNS_MESSAGE_HANDSHAKE_DONE 20 #define MS_NNS_MESSAGE_HANDSHAKE_ERROR 21 #define MS_NNS_MESSAGE_HANDSHAKE_PROGRESS 22 static const value_string nns_message_id_vals[] = { { MS_NNS_MESSAGE_HANDSHAKE_DONE, "Handshake Done" }, { MS_NNS_MESSAGE_HANDSHAKE_ERROR, "Handshake Error" }, { MS_NNS_MESSAGE_HANDSHAKE_PROGRESS, "Handshake In Progress" }, { 0, NULL} }; struct nns_session_state { guint32 handshake_done; gboolean first_handshake_done; }; static int proto_nns = -1; static int hf_nns_message_id = -1; static int hf_nns_major_version = -1; static int hf_nns_minor_version = -1; static int hf_nns_auth_payload_size = -1; static int hf_nns_auth_payload = -1; static int hf_nns_payload_size = -1; static int hf_nns_payload = -1; static gint ett_nns = -1; static gint ett_nns_payload = -1; #define MS_NNS_MIN_LENGTH 4 static int dissect_nns(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_item *ti, *pti; proto_tree *nns_tree, *payload_tree; guint offset = 0; guint32 message_id; guint32 payload_size; conversation_t *conversation; tvbuff_t *nt_tvb; gint remaining; struct nns_session_state *session_state; if (tvb_reported_length(tvb) < MS_NNS_MIN_LENGTH) return 0; conversation = find_or_create_conversation(pinfo); session_state = (struct nns_session_state *)conversation_get_proto_data(conversation, proto_nns); if (!session_state) { session_state = wmem_new0(wmem_file_scope(), struct nns_session_state); conversation_add_proto_data(conversation, proto_nns, session_state); } col_set_str(pinfo->cinfo, COL_PROTOCOL, "MS-NNS"); col_clear(pinfo->cinfo, COL_INFO); ti = proto_tree_add_item(tree, proto_nns, tvb, 0, -1, ENC_NA); nns_tree = proto_item_add_subtree(ti, ett_nns); /* As it is unknown if there is a one-way Handshake Done or a two-way Handshake Done we check the first frame * after the first Handshake Done if it looks like a Handshake Done message (0x140100). */ if ( session_state->handshake_done && session_state->handshake_done < pinfo->num && !(session_state->first_handshake_done && tvb_get_ntoh24(tvb, offset) == 0x140100)) { proto_tree_add_item_ret_uint(nns_tree, hf_nns_payload_size, tvb, offset, 4, ENC_LITTLE_ENDIAN, &payload_size); offset += 4; col_append_str(pinfo->cinfo, COL_INFO, "Data"); if ( payload_size > 0) { remaining = tvb_reported_length_remaining(tvb, offset); if ((guint32) remaining < payload_size) { pinfo->desegment_offset = offset - 4; pinfo->desegment_len = payload_size - remaining; return (offset - 4); } proto_tree_add_item(nns_tree, hf_nns_payload, tvb, offset, payload_size, ENC_NA); offset += payload_size; session_state->first_handshake_done = FALSE; } } else { proto_tree_add_item_ret_uint(nns_tree, hf_nns_message_id, tvb, offset, 1, ENC_NA, &message_id); offset += 1; col_append_sep_fstr(pinfo->cinfo, COL_INFO, ", ", "%s", val_to_str_const(message_id, nns_message_id_vals, "Unknown Record")); proto_tree_add_item(nns_tree, hf_nns_major_version, tvb, offset, 1, ENC_NA); offset += 1; proto_tree_add_item(nns_tree, hf_nns_minor_version, tvb, offset, 1, ENC_NA); offset += 1; proto_tree_add_item_ret_uint(nns_tree, hf_nns_auth_payload_size, tvb, offset, 2, ENC_BIG_ENDIAN, &payload_size); offset += 2; if ( payload_size > 0) { if ((guint32) tvb_reported_length_remaining(tvb, offset) < payload_size) { pinfo->desegment_offset = offset - 5; pinfo->desegment_len = payload_size; return (offset - 5); } pti = proto_tree_add_item(nns_tree, hf_nns_auth_payload, tvb, offset, payload_size, ENC_NA); if (message_id == MS_NNS_MESSAGE_HANDSHAKE_DONE || message_id == MS_NNS_MESSAGE_HANDSHAKE_PROGRESS) { nt_tvb = tvb_new_subset_length(tvb, offset, payload_size); payload_tree = proto_item_add_subtree(pti, ett_nns_payload); call_dissector(gssapi_handle, nt_tvb, pinfo, payload_tree); } offset += payload_size; } if ( message_id == MS_NNS_MESSAGE_HANDSHAKE_DONE) { session_state->handshake_done = pinfo->num; session_state->first_handshake_done = (session_state->first_handshake_done ? FALSE : TRUE); } } return offset; } void proto_register_nns(void) { static hf_register_info hf[] = { { &hf_nns_message_id, { "MessageID", "ms-nns.message_id", FT_UINT8, BASE_DEC, VALS(nns_message_id_vals), 0x0, NULL, HFILL } }, { &hf_nns_major_version, { "Major Version", "ms-nns.major_version", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_nns_minor_version, { "Minor Version", "ms-nns.minor_version", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_nns_auth_payload_size, { "Auth Payload Size", "ms-nns.auth_payload_size", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_nns_auth_payload, { "Auth Payload", "ms-nns.known_encoding", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, { &hf_nns_payload_size, { "Payload Size", "ms-nns.payload_size", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_nns_payload, { "Payload", "ms-nns.payload", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } } }; static gint *ett[] = { &ett_nns, &ett_nns_payload }; proto_nns = proto_register_protocol(".NET NegotiateStream Protocol", "MS-NNS", "ms-nns"); proto_register_field_array(proto_nns, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); register_dissector("ms-nns", dissect_nns, proto_nns); } void proto_reg_handoff_nns(void) { gssapi_handle = find_dissector("gssapi"); } /* * 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: */