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/* packet-credssp.c
* Routines for CredSSP (Credential Security Support Provider) packet dissection
* Graeme Lunt 2011
*
* 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/asn1.h>
#include <epan/tap.h>
#include <epan/exported_pdu.h>
#include "packet-ber.h"
#include "packet-credssp.h"
#define PNAME "Credential Security Support Provider"
#define PSNAME "CredSSP"
#define PFNAME "credssp"
#define TS_PASSWORD_CREDS 1
#define TS_SMARTCARD_CREDS 2
static gint creds_type;
static gint exported_pdu_tap = -1;
/* Initialize the protocol and registered fields */
static int proto_credssp = -1;
/* List of dissectors to call for negoToken data */
static heur_dissector_list_t credssp_heur_subdissector_list;
static int hf_credssp_TSPasswordCreds = -1; /* TSPasswordCreds */
static int hf_credssp_TSSmartCardCreds = -1; /* TSSmartCardCreds */
static int hf_credssp_TSCredentials = -1; /* TSCredentials */
#include "packet-credssp-hf.c"
/* Initialize the subtree pointers */
static gint ett_credssp = -1;
#include "packet-credssp-ett.c"
#include "packet-credssp-fn.c"
/*
* Dissect CredSSP PDUs
*/
static int
dissect_credssp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data)
{
proto_item *item=NULL;
proto_tree *tree=NULL;
if(parent_tree){
item = proto_tree_add_item(parent_tree, proto_credssp, tvb, 0, -1, ENC_NA);
tree = proto_item_add_subtree(item, ett_credssp);
}
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CredSSP");
col_clear(pinfo->cinfo, COL_INFO);
creds_type = -1;
return dissect_TSRequest_PDU(tvb, pinfo, tree, data);
}
static gboolean
dissect_credssp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
{
asn1_ctx_t asn1_ctx;
int offset = 0;
gint8 ber_class;
gboolean pc;
gint32 tag;
guint32 length;
gint8 ver;
asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);
/* Look for SEQUENCE, CONTEXT 0, and INTEGER 2 */
if(tvb_captured_length(tvb) > 7) {
offset = get_ber_identifier(tvb, offset, &ber_class, &pc, &tag);
if((ber_class == BER_CLASS_UNI) && (tag == BER_UNI_TAG_SEQUENCE) && (pc == TRUE)) {
offset = get_ber_length(tvb, offset, NULL, NULL);
offset = get_ber_identifier(tvb, offset, &ber_class, &pc, &tag);
if((ber_class == BER_CLASS_CON) && (tag == 0)) {
offset = get_ber_length(tvb, offset, NULL, NULL);
offset = get_ber_identifier(tvb, offset, &ber_class, &pc, &tag);
if((ber_class == BER_CLASS_UNI) && (tag == BER_UNI_TAG_INTEGER)) {
offset = get_ber_length(tvb, offset, &length, NULL);
ver = tvb_get_guint8(tvb, offset);
if((length == 1) && ((ver == 2) || (ver == 3))) {
if (have_tap_listener(exported_pdu_tap)) {
exp_pdu_data_t *exp_pdu_data = export_pdu_create_common_tags(pinfo, "credssp", EXP_PDU_TAG_PROTO_NAME);
exp_pdu_data->tvb_captured_length = tvb_captured_length(tvb);
exp_pdu_data->tvb_reported_length = tvb_reported_length(tvb);
exp_pdu_data->pdu_tvb = tvb;
tap_queue_packet(exported_pdu_tap, pinfo, exp_pdu_data);
}
dissect_credssp(tvb, pinfo, parent_tree, NULL);
return TRUE;
}
}
}
}
}
return FALSE;
}
/*--- proto_register_credssp -------------------------------------------*/
void proto_register_credssp(void) {
/* List of fields */
static hf_register_info hf[] =
{
{ &hf_credssp_TSPasswordCreds,
{ "TSPasswordCreds", "credssp.TSPasswordCreds",
FT_NONE, BASE_NONE, NULL, 0,
NULL, HFILL }},
{ &hf_credssp_TSSmartCardCreds,
{ "TSSmartCardCreds", "credssp.TSSmartCardCreds",
FT_NONE, BASE_NONE, NULL, 0,
NULL, HFILL }},
{ &hf_credssp_TSCredentials,
{ "TSCredentials", "credssp.TSCredentials",
FT_NONE, BASE_NONE, NULL, 0,
NULL, HFILL }},
#include "packet-credssp-hfarr.c"
};
/* List of subtrees */
static gint *ett[] = {
&ett_credssp,
#include "packet-credssp-ettarr.c"
};
/* Register protocol */
proto_credssp = proto_register_protocol(PNAME, PSNAME, PFNAME);
register_dissector("credssp", dissect_credssp, proto_credssp);
/* Register fields and subtrees */
proto_register_field_array(proto_credssp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* heuristic dissectors for any premable e.g. CredSSP before RDP */
credssp_heur_subdissector_list = register_heur_dissector_list("credssp", proto_credssp);
}
/*--- proto_reg_handoff_credssp --- */
void proto_reg_handoff_credssp(void) {
heur_dissector_add("tls", dissect_credssp_heur, "CredSSP over TLS", "credssp_tls", proto_credssp, HEURISTIC_ENABLE);
exported_pdu_tap = find_tap_id(EXPORT_PDU_TAP_NAME_LAYER_7);
}
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