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/* packet-rdpudp.c
* Routines for RDP multi transport packet dissection
* Copyright 2021, David Fort
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include <epan/conversation.h>
#include "packet-rdp.h"
#include "packet-rdpudp.h"
#define PNAME "Remote Desktop Protocol Multi-transport"
#define PSNAME "RDPMT"
#define PFNAME "rdpmt"
void proto_register_rdpmt(void);
void proto_reg_handoff_rdpmt(void);
static dissector_handle_t rdpmt_handle;
static int proto_rdpmt = -1;
static int pf_mt_action = -1;
static int pf_mt_flags = -1;
static int pf_mt_payload_len = -1;
static int pf_mt_header_len = -1;
static int pf_mt_subheader_len = -1;
static int pf_mt_subheader_type = -1;
static int pf_mt_createreq_reqId = -1;
static int pf_mt_createreq_reserved = -1;
static int pf_mt_createreq_cookie = -1;
static int pf_mt_createresp_hrResponse = -1;
static int ett_rdpmt = -1;
static int ett_rdpudp_subheaders = -1;
static int ett_rdpmt_create_req = -1;
static int ett_rdpmt_create_resp = -1;
static int ett_rdpmt_data = -1;
static dissector_handle_t drdynvcDissector;
static const value_string rdpmt_action_vals[] = {
{ 0x00, "CreateRequest"},
{ 0x01, "CreateResponse"},
{ 0x02, "Data"},
{ 0x00, NULL}
};
static const value_string rdpmt_subheader_type_vals[] = {
{ 0x0, "auto detect request" },
{ 0x1, "auto detect response" },
{ 0x0, NULL}
};
enum {
RDPMT_TUNNEL_CREATE_REQ = 0,
RDPMT_TUNNEL_CREATE_RESP = 1,
RDPMT_TUNNEL_DATA = 2,
};
static int
dissect_rdpmt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
proto_item *item;
proto_tree *tree, *subtree;
guint8 action, subheader_len;
guint16 payload_len;
int offset = 0;
item = proto_tree_add_item(parent_tree, proto_rdpmt, tvb, 0, -1, ENC_NA);
tree = proto_item_add_subtree(item, ett_rdpmt);
action = tvb_get_guint8(tvb, offset) & 0x0f;
proto_tree_add_item(tree, pf_mt_action, tvb, offset, 1, ENC_NA);
proto_tree_add_item(tree, pf_mt_flags, tvb, offset, 1, ENC_NA);
offset++;
payload_len = tvb_get_guint16(tvb, offset, ENC_LITTLE_ENDIAN);
proto_tree_add_item(tree, pf_mt_payload_len, tvb, offset, 2, ENC_LITTLE_ENDIAN);
offset += 2;
subheader_len = tvb_get_guint8(tvb, offset);
proto_tree_add_item(tree, pf_mt_header_len, tvb, offset, 1, ENC_NA);
offset += 1;
if (subheader_len > 4) {
tvbuff_t *subheaders = tvb_new_subset_length(tvb, offset, subheader_len-4);
proto_tree *subheaders_tree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_rdpudp_subheaders, NULL, "SubHeaders");
dissect_rdp_bandwidth_req(subheaders, 0, pinfo, subheaders_tree, !!rdp_isServerAddressTarget(pinfo));
}
offset += subheader_len - 4;
switch (action) {
case RDPMT_TUNNEL_CREATE_REQ: {
guint8 cookie[16];
guint32 reqId;
conversation_t *conv = find_or_create_conversation(pinfo);
col_set_str(pinfo->cinfo, COL_INFO, "TunnelCreateRequest");
subtree = proto_tree_add_subtree(tree, tvb, offset, payload_len, ett_rdpmt_create_req, NULL, "TunnelCreateRequest");
proto_tree_add_item(subtree, pf_mt_createreq_reqId, tvb, offset, 4, ENC_LITTLE_ENDIAN);
reqId = tvb_get_guint32(tvb, offset, ENC_LITTLE_ENDIAN);
offset += 4;
proto_tree_add_item(subtree, pf_mt_createreq_reserved, tvb, offset, 4, ENC_LITTLE_ENDIAN);
offset += 4;
proto_tree_add_item(subtree, pf_mt_createreq_cookie, tvb, offset, 16, ENC_NA);
tvb_memcpy(tvb, cookie, offset, 16);
offset += 4;
rdp_transport_set_udp_conversation(&pinfo->dst, pinfo->destport, rdpudp_is_reliable_transport(pinfo), reqId, cookie, conv);
break;
}
case RDPMT_TUNNEL_CREATE_RESP:
col_set_str(pinfo->cinfo, COL_INFO, "TunnelCreateResponse");
subtree = proto_tree_add_subtree(tree, tvb, offset, payload_len, ett_rdpmt_create_resp, NULL, "TunnelCreateResponse");
proto_tree_add_item(subtree, pf_mt_createresp_hrResponse, tvb, offset, 4, ENC_LITTLE_ENDIAN);
break;
case RDPMT_TUNNEL_DATA:
if (payload_len) {
tvbuff_t *payload = tvb_new_subset_length(tvb, offset, payload_len);
subtree = proto_tree_add_subtree(tree, tvb, offset, -1, ett_rdpmt_data, NULL, "Data");
call_dissector(drdynvcDissector, payload, pinfo, subtree);
}
break;
}
return offset;
}
void
proto_register_rdpmt(void) {
/* List of fields */
static hf_register_info hf[] = {
{ &pf_mt_action,
{"Action", "rdpmt.action", FT_UINT8, BASE_HEX, VALS(rdpmt_action_vals), 0x0F, NULL, HFILL}
},
{&pf_mt_flags,
{"Flags", "rdpmt.flags", FT_UINT8, BASE_HEX, NULL, 0xF0, NULL, HFILL}
},
{&pf_mt_payload_len,
{"Payload length", "rdpmt.payloadlen", FT_UINT16, BASE_DEC, NULL, 0, NULL, HFILL}
},
{&pf_mt_header_len,
{"Header length", "rdpmt.headerlen", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL}
},
{&pf_mt_subheader_len,
{"Sub header length", "rdpmt.subheaderlen", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL}
},
{&pf_mt_subheader_type,
{"Sub header type", "rdpmt.subheadertype", FT_UINT8, BASE_HEX, VALS(rdpmt_subheader_type_vals), 0, NULL, HFILL}
},
{&pf_mt_createreq_reqId,
{"RequestID", "rdpmt.createrequest.requestid", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL}
},
{&pf_mt_createreq_reserved,
{"Reserved", "rdpmt.createrequest.reserved", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL}
},
{&pf_mt_createreq_cookie,
{"Security cookie", "rdpmt.createrequest.cookie", FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL}
},
{&pf_mt_createresp_hrResponse,
{"hrResponse", "rdpmt.createresponse.hrresponse", FT_INT32, BASE_DEC, NULL, 0, NULL, HFILL}
}
};
/* List of subtrees */
static gint *ett[] = {
&ett_rdpmt,
&ett_rdpudp_subheaders,
&ett_rdpmt_create_req,
&ett_rdpmt_create_resp,
&ett_rdpmt_data
};
/* Register protocol */
proto_rdpmt = proto_register_protocol(PNAME, PSNAME, PFNAME);
/* Register fields and subtrees */
proto_register_field_array(proto_rdpmt, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
rdpmt_handle = register_dissector("rdpmt", dissect_rdpmt, proto_rdpmt);
}
static gboolean
rdpmt_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
guint8 action, header_len;
guint16 payload_len;
if (tvb_reported_length(tvb) <= 4)
return FALSE;
action = tvb_get_guint8(tvb, 0);
if (action > 2)
return FALSE;
payload_len = tvb_get_guint16(tvb, 1, ENC_LITTLE_ENDIAN);
header_len = tvb_get_guint8(tvb, 3);
if ((header_len < 4UL) || (tvb_reported_length_remaining(tvb, header_len) < payload_len))
return FALSE;
if (header_len > 4) {
guint8 subheader_len, subheader_type;
if(header_len < 6)
return FALSE;
subheader_len = tvb_get_guint8(tvb, 4);
if ((subheader_len < 2) || (subheader_len > header_len-4))
return FALSE;
subheader_type = tvb_get_guint8(tvb, 5);
if (subheader_type > 1) /* AUTODETECT_REQUEST or AUTODETECT_RESPONSE */
return FALSE;
}
return dissect_rdpmt(tvb, pinfo, tree, data) > 0;
}
void
proto_reg_handoff_rdpmt(void)
{
drdynvcDissector = find_dissector("rdp_drdynvc");
heur_dissector_add("tls", rdpmt_heur, "RDP MultiTransport", "rdpmt_tls_", proto_rdpmt, TRUE);
heur_dissector_add("dtls", rdpmt_heur, "RDP MultiTransport", "rdpmt_dtls", proto_rdpmt, TRUE);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local Variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
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