329 lines
10 KiB
C
329 lines
10 KiB
C
/* packet-kpasswd.c
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* Routines for kpasswd packet dissection
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* Ronnie Sahlberg 2003
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*
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* See RFC 3244
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/asn1.h>
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#include "packet-tcp.h"
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#include "packet-kerberos.h"
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#include <epan/prefs.h>
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void proto_register_kpasswd(void);
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void proto_reg_handoff_kpasswd(void);
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/* Desegment Kerberos over TCP messages */
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static gboolean kpasswd_desegment = TRUE;
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static int proto_kpasswd = -1;
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static int hf_kpasswd_message_len = -1;
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static int hf_kpasswd_version = -1;
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static int hf_kpasswd_result = -1;
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static int hf_kpasswd_result_string = -1;
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static int hf_kpasswd_ap_req_len = -1;
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static int hf_kpasswd_ap_req_data = -1;
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static int hf_kpasswd_krb_priv_message = -1;
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static int hf_kpasswd_ChangePasswdData = -1;
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static gint ett_kpasswd = -1;
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static gint ett_ap_req_data = -1;
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static gint ett_krb_priv_message = -1;
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#define UDP_PORT_KPASSWD 464
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#define TCP_PORT_KPASSWD 464
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static const value_string vers_vals[] = {
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{ 0x0001, "Reply" },
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{ 0xff80, "Request" },
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{ 0, NULL },
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};
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/** Dissects AP-REQ or AP-REP part of password change. */
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static void
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dissect_kpasswd_ap_req_data(packet_info *pinfo _U_, tvbuff_t *tvb, proto_tree *parent_tree)
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{
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proto_item *it;
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proto_tree *tree;
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it=proto_tree_add_item(parent_tree, hf_kpasswd_ap_req_data, tvb, 0, -1, ENC_NA);
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tree=proto_item_add_subtree(it, ett_ap_req_data);
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dissect_kerberos_main(tvb, pinfo, tree, FALSE, NULL);
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}
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static int
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dissect_kpasswd_user_data_request(packet_info *pinfo, tvbuff_t *tvb, proto_tree *tree)
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{
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int offset=0;
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asn1_ctx_t asn1_ctx;
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asn1_ctx_init(&asn1_ctx, ASN1_ENC_BER, TRUE, pinfo);
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offset=dissect_kerberos_ChangePasswdData (FALSE, tvb, offset, &asn1_ctx, tree, hf_kpasswd_ChangePasswdData);
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return offset;
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}
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static kerberos_callbacks cb_req[] = {
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{ KRB_CBTAG_PRIV_USER_DATA, dissect_kpasswd_user_data_request },
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{ 0, NULL }
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};
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#define KRB5_KPASSWD_SUCCESS 0
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#define KRB5_KPASSWD_MALFORMED 1
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#define KRB5_KPASSWD_HARDERROR 2
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#define KRB5_KPASSWD_AUTHERROR 3
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#define KRB5_KPASSWD_SOFTERROR 4
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#define KRB5_KPASSWD_ACCESSDENIED 5
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#define KRB5_KPASSWD_BAD_VERSION 6
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#define KRB5_KPASSWD_INITIAL_FLAG_NEEDED 7
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static const value_string kpasswd_result_types[] = {
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{ KRB5_KPASSWD_SUCCESS, "Success" },
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{ KRB5_KPASSWD_MALFORMED, "Malformed" },
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{ KRB5_KPASSWD_HARDERROR, "HardError" },
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{ KRB5_KPASSWD_AUTHERROR, "AuthError" },
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{ KRB5_KPASSWD_SOFTERROR, "SoftError" },
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{ KRB5_KPASSWD_ACCESSDENIED, "AccessDenied" },
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{ KRB5_KPASSWD_BAD_VERSION, "BadVersion" },
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{ KRB5_KPASSWD_INITIAL_FLAG_NEEDED, "InitialFlagNeeded" },
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{ 0, NULL }
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};
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static int
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dissect_kpasswd_user_data_reply(packet_info *pinfo, tvbuff_t *tvb, proto_tree *tree)
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{
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int offset=0;
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guint16 result;
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/* result */
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result = tvb_get_ntohs(tvb, offset);
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proto_tree_add_uint(tree, hf_kpasswd_result, tvb, offset, 2, result);
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offset+=2;
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col_add_str(pinfo->cinfo, COL_INFO,
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val_to_str(result, kpasswd_result_types, "Result: %u"));
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/* optional result string */
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if(tvb_reported_length_remaining(tvb, offset) > 0){
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proto_tree_add_item(tree, hf_kpasswd_result_string, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII|ENC_NA);
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offset = tvb_reported_length(tvb);
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}
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return offset;
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}
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static kerberos_callbacks cb_rep[] = {
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{ KRB_CBTAG_PRIV_USER_DATA, dissect_kpasswd_user_data_reply },
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{ 0, NULL }
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};
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static gint
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dissect_kpasswd_krb_priv_message(packet_info *pinfo _U_, tvbuff_t *tvb, proto_tree *parent_tree, gboolean isrequest)
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{
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proto_item *it;
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proto_tree *tree=NULL;
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gint offset;
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if(parent_tree){
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it=proto_tree_add_item(parent_tree, hf_kpasswd_krb_priv_message, tvb, 0, -1, ENC_NA);
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tree=proto_item_add_subtree(it, ett_krb_priv_message);
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}
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if(isrequest){
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offset = dissect_kerberos_main(tvb, pinfo, tree, FALSE, cb_req);
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} else {
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offset = dissect_kerberos_main(tvb, pinfo, tree, FALSE, cb_rep);
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}
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/* offset is bytes consumed in child tvb given to us */
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return offset;
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}
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static gint
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dissect_kpasswd_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, gboolean have_rm)
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{
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proto_item *kpasswd_item=NULL;
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proto_tree *kpasswd_tree=NULL;
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int offset = 0;
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guint16 message_len, version, ap_req_len;
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tvbuff_t *next_tvb;
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/* TCP record mark and length */
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guint32 krb_rm = 0;
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gint krb_reclen = 0;
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gint krb_rm_size = 0; /* bytes consumed by record mark: 0 or 4 */
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "KPASSWD");
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col_clear(pinfo->cinfo, COL_INFO);
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/* can't pass have_rm to dissect_kerberos_main, so strip rm first */
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if (have_rm) {
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krb_rm = tvb_get_ntohl(tvb, offset);
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krb_reclen = kerberos_rm_to_reclen(krb_rm);
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krb_rm_size = 4;
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/*
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* What is a reasonable size limit?
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*/
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if (krb_reclen > 10 * 1024 * 1024) {
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return (-1);
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}
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offset += krb_rm_size;
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}
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/* it might be a KERBEROS ERROR */
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if(tvb_get_guint8(tvb, offset)==0x7e){
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/* TCP record mark, if any, not displayed. But hopefully
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* KRB-ERROR dissection will proceed correctly. */
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next_tvb=tvb_new_subset_remaining(tvb, offset);
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return dissect_kerberos_main(next_tvb, pinfo, tree, FALSE, NULL);
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}
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message_len=tvb_get_ntohs(tvb, offset);
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version=tvb_get_ntohs(tvb, offset+2);
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ap_req_len=tvb_get_ntohs(tvb, offset+4);
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if(tree){
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kpasswd_item=proto_tree_add_item(tree, proto_kpasswd, tvb, offset-krb_rm_size, message_len+krb_rm_size, ENC_NA);
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kpasswd_tree=proto_item_add_subtree(kpasswd_item, ett_kpasswd);
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if (have_rm) {
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show_krb_recordmark(kpasswd_tree, tvb, offset-krb_rm_size, krb_rm);
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}
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}
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proto_tree_add_uint(kpasswd_tree, hf_kpasswd_message_len, tvb, offset, 2, message_len);
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proto_tree_add_uint(kpasswd_tree, hf_kpasswd_version, tvb, offset+2, 2, version);
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col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(version, vers_vals, "Unknown command"));
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proto_tree_add_uint(kpasswd_tree, hf_kpasswd_ap_req_len, tvb, offset+4, 2, ap_req_len);
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offset+=6;
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/* AP-REQ / AP-REP data */
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next_tvb=tvb_new_subset_length(tvb, offset, ap_req_len);
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dissect_kpasswd_ap_req_data(pinfo, next_tvb, kpasswd_tree);
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offset+=ap_req_len;
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/* KRB-PRIV message */
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next_tvb=tvb_new_subset_remaining(tvb, offset);
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offset += dissect_kpasswd_krb_priv_message(pinfo, next_tvb, kpasswd_tree, (version==0xff80));
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proto_item_set_len(kpasswd_item, offset);
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return offset;
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}
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static int
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dissect_kpasswd_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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dissect_kpasswd_common(tvb, pinfo, tree, FALSE);
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return tvb_captured_length(tvb);
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}
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static int
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dissect_kpasswd_tcp_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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pinfo->fragmented = TRUE;
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if (dissect_kpasswd_common(tvb, pinfo, tree, TRUE) < 0) {
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/*
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* The dissector failed to recognize this as a valid
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* Kerberos message. Mark it as a continuation packet.
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*/
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col_set_str(pinfo->cinfo, COL_INFO, "Continuation");
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}
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return tvb_captured_length(tvb);
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}
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static int
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dissect_kpasswd_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
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{
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "KPASSWD");
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col_clear(pinfo->cinfo, COL_INFO);
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tcp_dissect_pdus(tvb, pinfo, tree, kpasswd_desegment, 4, get_krb_pdu_len, dissect_kpasswd_tcp_pdu, data);
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return tvb_captured_length(tvb);
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}
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void
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proto_register_kpasswd(void)
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{
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static hf_register_info hf[] = {
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{ &hf_kpasswd_message_len,
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{ "Message Length", "kpasswd.message_len", FT_UINT16, BASE_DEC,
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NULL, 0, NULL, HFILL }},
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{ &hf_kpasswd_ap_req_len,
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{ "AP_REQ Length", "kpasswd.ap_req_len", FT_UINT16, BASE_DEC,
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NULL, 0, "Length of AP_REQ data", HFILL }},
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{ &hf_kpasswd_version,
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{ "Version", "kpasswd.version", FT_UINT16, BASE_HEX,
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VALS(vers_vals), 0, NULL, HFILL }},
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{ &hf_kpasswd_result,
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{ "Result", "kpasswd.result", FT_UINT16, BASE_DEC,
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VALS(kpasswd_result_types), 0, NULL, HFILL }},
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{ &hf_kpasswd_result_string,
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{ "Result String", "kpasswd.result_string", FT_STRING, BASE_NONE,
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NULL, 0, NULL, HFILL }},
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{ &hf_kpasswd_ap_req_data,
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{ "AP_REQ", "kpasswd.ap_req", FT_NONE, BASE_NONE,
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NULL, 0, "AP_REQ structure", HFILL }},
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{ &hf_kpasswd_krb_priv_message,
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{ "KRB-PRIV", "kpasswd.krb_priv", FT_NONE, BASE_NONE,
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NULL, 0, "KRB-PRIV message", HFILL }},
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{ &hf_kpasswd_ChangePasswdData, {
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"ChangePasswdData", "kpasswd.ChangePasswdData", FT_NONE, BASE_NONE,
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NULL, 0, "Change Password Data structure", HFILL }},
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};
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static gint *ett[] = {
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&ett_kpasswd,
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&ett_ap_req_data,
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&ett_krb_priv_message,
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};
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module_t *kpasswd_module;
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proto_kpasswd = proto_register_protocol("MS Kpasswd",
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"Kpasswd", "kpasswd");
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proto_register_field_array(proto_kpasswd, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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/* Register preferences */
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kpasswd_module = prefs_register_protocol(proto_kpasswd, NULL);
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prefs_register_bool_preference(kpasswd_module, "desegment",
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"Reassemble Kpasswd over TCP messages spanning multiple TCP segments",
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"Whether the Kpasswd dissector should reassemble messages spanning multiple TCP segments."
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" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
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&kpasswd_desegment);
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}
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void
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proto_reg_handoff_kpasswd(void)
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{
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dissector_handle_t kpasswd_handle_udp;
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dissector_handle_t kpasswd_handle_tcp;
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kpasswd_handle_udp = create_dissector_handle(dissect_kpasswd_udp, proto_kpasswd);
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kpasswd_handle_tcp = create_dissector_handle(dissect_kpasswd_tcp, proto_kpasswd);
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dissector_add_uint_with_preference("udp.port", UDP_PORT_KPASSWD, kpasswd_handle_udp);
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dissector_add_uint_with_preference("tcp.port", TCP_PORT_KPASSWD, kpasswd_handle_tcp);
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}
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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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