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wireshark/packet-tacacs.c

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/* packet-tacacs.c
* Routines for cisco tacacs/xtacacs/tacacs+ packet dissection
* Copyright 2001, Paul Ionescu <paul@acorp.ro>
*
* Full Tacacs+ parsing with decryption by
* Emanuele Caratti <wiz@iol.it>
*
* $Id: packet-tacacs.c,v 1.32 2003/12/19 19:03:13 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* Copyright 1998 Gerald Combs
*
* Copied from old packet-tacacs.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* rfc-1492 for tacacs and xtacacs
* draft-grant-tacacs-02.txt for tacacs+ (tacplus)
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <string.h>
#include <glib.h>
#include <epan/packet.h>
#include "prefs.h"
#include "crypt-md5.h"
#include "packet-tacacs.h"
static void md5_xor( guint8 *data, char *key, int data_len, guint8 *session_id, guint8 version, guint8 seq_no );
static int proto_tacacs = -1;
static int hf_tacacs_version = -1;
static int hf_tacacs_type = -1;
static int hf_tacacs_nonce = -1;
static int hf_tacacs_userlen = -1;
static int hf_tacacs_passlen = -1;
static int hf_tacacs_response = -1;
static int hf_tacacs_reason = -1;
static int hf_tacacs_result1 = -1;
static int hf_tacacs_destaddr = -1;
static int hf_tacacs_destport = -1;
static int hf_tacacs_line = -1;
static int hf_tacacs_result2 = -1;
static int hf_tacacs_result3 = -1;
static gint ett_tacacs = -1;
static char *tacplus_opt_key;
static GSList *tacplus_keys = NULL;
#define VERSION_TACACS 0x00
#define VERSION_XTACACS 0x80
static const value_string tacacs_version_vals[] = {
{ VERSION_TACACS, "TACACS" },
{ VERSION_XTACACS, "XTACACS" },
{ 0, NULL }
};
#define TACACS_LOGIN 1
#define TACACS_RESPONSE 2
#define TACACS_CHANGE 3
#define TACACS_FOLLOW 4
#define TACACS_CONNECT 5
#define TACACS_SUPERUSER 6
#define TACACS_LOGOUT 7
#define TACACS_RELOAD 8
#define TACACS_SLIP_ON 9
#define TACACS_SLIP_OFF 10
#define TACACS_SLIP_ADDR 11
static const value_string tacacs_type_vals[] = {
{ TACACS_LOGIN, "Login" },
{ TACACS_RESPONSE, "Response" },
{ TACACS_CHANGE, "Change" },
{ TACACS_FOLLOW, "Follow" },
{ TACACS_CONNECT, "Connect" },
{ TACACS_SUPERUSER, "Superuser" },
{ TACACS_LOGOUT, "Logout" },
{ TACACS_RELOAD, "Reload" },
{ TACACS_SLIP_ON, "SLIP on" },
{ TACACS_SLIP_OFF, "SLIP off" },
{ TACACS_SLIP_ADDR, "SLIP Addr" },
{ 0, NULL }};
static const value_string tacacs_reason_vals[] = {
{ 0 , "none" },
{ 1 , "expiring" },
{ 2 , "password" },
{ 3 , "denied" },
{ 4 , "quit" },
{ 5 , "idle" },
{ 6 , "drop" },
{ 7 , "bad" },
{ 0 , NULL }
};
static const value_string tacacs_resp_vals[] = {
{ 0 , "this is not a response" },
{ 1 , "accepted" },
{ 2 , "rejected" },
{ 0 , NULL }
};
#define UDP_PORT_TACACS 49
#define TCP_PORT_TACACS 49
static void
dissect_tacacs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree *tacacs_tree;
proto_item *ti;
guint8 txt_buff[255+1],version,type,userlen,passlen;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TACACS");
if (check_col(pinfo->cinfo, COL_INFO))
col_clear(pinfo->cinfo, COL_INFO);
version = tvb_get_guint8(tvb,0);
if (version != 0) {
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "XTACACS");
}
type = tvb_get_guint8(tvb,1);
if (check_col(pinfo->cinfo, COL_INFO))
col_add_str(pinfo->cinfo, COL_INFO,
val_to_str(type, tacacs_type_vals, "Unknown (0x%02x)"));
if (tree)
{
ti = proto_tree_add_protocol_format(tree, proto_tacacs,
tvb, 0, -1, version==0?"TACACS":"XTACACS");
tacacs_tree = proto_item_add_subtree(ti, ett_tacacs);
proto_tree_add_uint(tacacs_tree, hf_tacacs_version, tvb, 0, 1,
version);
proto_tree_add_uint(tacacs_tree, hf_tacacs_type, tvb, 1, 1,
type);
proto_tree_add_item(tacacs_tree, hf_tacacs_nonce, tvb, 2, 2,
FALSE);
if (version==0)
{
if (type!=TACACS_RESPONSE)
{
userlen=tvb_get_guint8(tvb,4);
proto_tree_add_uint(tacacs_tree, hf_tacacs_userlen, tvb, 4, 1,
userlen);
passlen=tvb_get_guint8(tvb,5);
proto_tree_add_uint(tacacs_tree, hf_tacacs_passlen, tvb, 5, 1,
passlen);
tvb_get_nstringz0(tvb,6,userlen+1,txt_buff);
proto_tree_add_text(tacacs_tree, tvb, 6, userlen, "Username: %s",txt_buff);
tvb_get_nstringz0(tvb,6+userlen,passlen+1,txt_buff);
proto_tree_add_text(tacacs_tree, tvb, 6+userlen, passlen, "Password: %s",txt_buff);
}
else
{
proto_tree_add_item(tacacs_tree, hf_tacacs_response, tvb, 4, 1,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_reason, tvb, 5, 1,
FALSE);
}
}
else
{
userlen=tvb_get_guint8(tvb,4);
proto_tree_add_uint(tacacs_tree, hf_tacacs_userlen, tvb, 4, 1,
userlen);
passlen=tvb_get_guint8(tvb,5);
proto_tree_add_uint(tacacs_tree, hf_tacacs_passlen, tvb, 5, 1,
passlen);
proto_tree_add_item(tacacs_tree, hf_tacacs_response, tvb, 6, 1,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_reason, tvb, 7, 1,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_result1, tvb, 8, 4,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_destaddr, tvb, 12, 4,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_destport, tvb, 16, 2,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_line, tvb, 18, 2,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_result2, tvb, 20, 4,
FALSE);
proto_tree_add_item(tacacs_tree, hf_tacacs_result3, tvb, 24, 2,
FALSE);
if (type!=TACACS_RESPONSE)
{
tvb_get_nstringz0(tvb,26,userlen+1,txt_buff);
proto_tree_add_text(tacacs_tree, tvb, 26, userlen, "Username: %s",txt_buff);
tvb_get_nstringz0(tvb,26+userlen,passlen+1,txt_buff);
proto_tree_add_text(tacacs_tree, tvb, 26+userlen, passlen, "Password; %s",txt_buff);
}
}
}
}
void
proto_register_tacacs(void)
{
static hf_register_info hf[] = {
{ &hf_tacacs_version,
{ "Version", "tacacs.version",
FT_UINT8, BASE_HEX, VALS(tacacs_version_vals), 0x0,
"Version", HFILL }},
{ &hf_tacacs_type,
{ "Type", "tacacs.type",
FT_UINT8, BASE_DEC, VALS(tacacs_type_vals), 0x0,
"Type", HFILL }},
{ &hf_tacacs_nonce,
{ "Nonce", "tacacs.nonce",
FT_UINT16, BASE_HEX, NULL, 0x0,
"Nonce", HFILL }},
{ &hf_tacacs_userlen,
{ "Username length", "tacacs.userlen",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Username length", HFILL }},
{ &hf_tacacs_passlen,
{ "Password length", "tacacs.passlen",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Password length", HFILL }},
{ &hf_tacacs_response,
{ "Response", "tacacs.response",
FT_UINT8, BASE_DEC, VALS(tacacs_resp_vals), 0x0,
"Response", HFILL }},
{ &hf_tacacs_reason,
{ "Reason", "tacacs.reason",
FT_UINT8, BASE_DEC, VALS(tacacs_reason_vals), 0x0,
"Reason", HFILL }},
{ &hf_tacacs_result1,
{ "Result 1", "tacacs.result1",
FT_UINT32, BASE_HEX, NULL, 0x0,
"Result 1", HFILL }},
{ &hf_tacacs_destaddr,
{ "Destination address", "tacacs.destaddr",
FT_IPv4, BASE_NONE, NULL, 0x0,
"Destination address", HFILL }},
{ &hf_tacacs_destport,
{ "Destination port", "tacacs.destport",
FT_UINT16, BASE_DEC, NULL, 0x0,
"Destination port", HFILL }},
{ &hf_tacacs_line,
{ "Line", "tacacs.line",
FT_UINT16, BASE_DEC, NULL, 0x0,
"Line", HFILL }},
{ &hf_tacacs_result2,
{ "Result 2", "tacacs.result2",
FT_UINT32, BASE_HEX, NULL, 0x0,
"Result 2", HFILL }},
{ &hf_tacacs_result3,
{ "Result 3", "tacacs.result3",
FT_UINT16, BASE_HEX, NULL, 0x0,
"Result 3", HFILL }},
};
static gint *ett[] = {
&ett_tacacs,
};
proto_tacacs = proto_register_protocol("TACACS", "TACACS", "tacacs");
proto_register_field_array(proto_tacacs, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_tacacs(void)
{
dissector_handle_t tacacs_handle;
tacacs_handle = create_dissector_handle(dissect_tacacs, proto_tacacs);
dissector_add("udp.port", UDP_PORT_TACACS, tacacs_handle);
}
static int proto_tacplus = -1;
static int hf_tacplus_response = -1;
static int hf_tacplus_request = -1;
static int hf_tacplus_majvers = -1;
static int hf_tacplus_minvers = -1;
static int hf_tacplus_type = -1;
static int hf_tacplus_seqno = -1;
static int hf_tacplus_flags = -1;
static int hf_tacplus_flags_payload_type = -1;
static int hf_tacplus_flags_connection_type = -1;
static int hf_tacplus_acct_flags = -1;
static int hf_tacplus_session_id = -1;
static int hf_tacplus_packet_len = -1;
static gint ett_tacplus = -1;
static gint ett_tacplus_body = -1;
static gint ett_tacplus_body_chap = -1;
static gint ett_tacplus_flags = -1;
static gint ett_tacplus_acct_flags = -1;
typedef struct _tacplus_key_entry {
address *s; /* Server address */
address *c; /* client address */
char *k; /* Key */
} tacplus_key_entry;
static gint
tacplus_decrypted_tvb_setup( tvbuff_t *tvb, tvbuff_t **dst_tvb, packet_info *pinfo, guint32 len, guint8 version, char *key )
{
guint8 *buff;
guint8 session_id[4];
/* TODO Check the possibility to use pinfo->decrypted_data */
/* session_id is in NETWORK Byte Order, and is used as byte array in the md5_xor */
tvb_memcpy(tvb, (guint8*)session_id, 4,4);
buff = tvb_memdup(tvb, TAC_PLUS_HDR_SIZE, len);
md5_xor( buff, key, len, session_id,version, tvb_get_guint8(tvb,2) );
/* Allocate a new tvbuff, referring to the decrypted data. */
*dst_tvb = tvb_new_real_data( buff, len, len );
/* Arrange that the allocated packet data copy be freed when the
tvbuff is freed. */
tvb_set_free_cb( *dst_tvb, g_free );
/* Add the tvbuff to the list of tvbuffs to which the tvbuff we
were handed refers, so it'll get cleaned up when that tvbuff
is cleaned up. */
tvb_set_child_real_data_tvbuff( tvb, *dst_tvb );
/* Add the decrypted data to the data source list. */
add_new_data_source(pinfo, *dst_tvb, "TACACS+ Decrypted");
return 0;
}
static void
dissect_tacplus_args_list( tvbuff_t *tvb, proto_tree *tree, int data_off, int len_off, int arg_cnt )
{
int i;
guint8 buff[257];
for(i=0;i<arg_cnt;i++){
int len=tvb_get_guint8(tvb,len_off+i);
proto_tree_add_text( tree, tvb, len_off+i, 1, "Arg[%d] length: %d", i, len );
tvb_get_nstringz0(tvb, data_off, len+1, buff);
proto_tree_add_text( tree, tvb, data_off, len, "Arg[%d] value: %s", i, buff );
data_off+=len;
}
}
static int
proto_tree_add_tacplus_common_fields( tvbuff_t *tvb, proto_tree *tree, int offset, int var_off )
{
int val;
guint8 buff[257];
/* priv_lvl */
proto_tree_add_text( tree, tvb, offset, 1,
"Privilege Level: %d", tvb_get_guint8(tvb,offset) );
offset++;
/* authen_type */
val=tvb_get_guint8(tvb,offset);
proto_tree_add_text( tree, tvb, offset, 1,
"Authentication type: %s",
val_to_str( val, tacplus_authen_type_vals, "Unknown Packet" ) );
offset++;
/* service */
val=tvb_get_guint8(tvb,offset);
proto_tree_add_text( tree, tvb, offset, 1,
"Service: %s",
val_to_str( val, tacplus_authen_service_vals, "Unknown Packet" ) );
offset++;
/* user_len && user */
val=tvb_get_guint8(tvb,offset);
proto_tree_add_text( tree, tvb, offset, 1, "User len: %d", val );
if( val ){
tvb_get_nstringz0(tvb, var_off, val+1, buff);
proto_tree_add_text( tree, tvb, var_off, val, "User: %s", buff );
var_off+=val;
}
offset++;
/* port_len && port */
val=tvb_get_guint8(tvb,offset);
proto_tree_add_text( tree, tvb, offset, 1, "Port len: %d", val );
if( val ){
tvb_get_nstringz0(tvb, var_off, val+1, buff);
proto_tree_add_text( tree, tvb, var_off, val, "Port: %s", buff );
var_off+=val;
}
offset++;
/* rem_addr_len && rem_addr */
val=tvb_get_guint8(tvb,offset);
proto_tree_add_text( tree, tvb, offset, 1, "Remaddr len: %d", val );
if( val ){
tvb_get_nstringz0(tvb, var_off, val+1, buff);
proto_tree_add_text( tree, tvb, var_off, val, "Remote Address: %s", buff );
var_off+=val;
}
return var_off;
}
static void
dissect_tacplus_body_authen_req_login( tvbuff_t* tvb, proto_tree *tree, int var_off )
{
guint8 buff[257];
guint8 val;
val=tvb_get_guint8( tvb, AUTHEN_S_DATA_LEN_OFF );
switch ( tvb_get_guint8(tvb, AUTHEN_S_AUTHEN_TYPE_OFF ) ) { /* authen_type */
case TAC_PLUS_AUTHEN_TYPE_ASCII:
proto_tree_add_text( tree, tvb, AUTHEN_S_DATA_LEN_OFF, 1, "Data: %d (not used)", val );
if( val )
proto_tree_add_text( tree, tvb, var_off, val, "Data" );
break;
case TAC_PLUS_AUTHEN_TYPE_PAP:
proto_tree_add_text( tree, tvb, AUTHEN_S_DATA_LEN_OFF, 1, "Password Length %d", val );
if( val ) {
tvb_get_nstringz0( tvb, var_off, val+1, buff );
proto_tree_add_text( tree, tvb, var_off, val, "Password: %s", buff );
}
break;
case TAC_PLUS_AUTHEN_TYPE_CHAP:
proto_tree_add_text( tree, tvb, AUTHEN_S_DATA_LEN_OFF, 1, "CHAP Data Length %d", val );
if( val ) {
proto_item *pi;
proto_tree *pt;
guint8 chal_len=val-(1+16); /* Response field alwayes 16 octets */
pi = proto_tree_add_text(tree, tvb, var_off, val, "CHAP Data" );
pt = proto_item_add_subtree( pi, ett_tacplus_body_chap );
val= tvb_get_guint8( tvb, var_off );
proto_tree_add_text( pt, tvb, var_off, 1, "ID: %d", val );
var_off++;
tvb_get_nstringz0( tvb, var_off, chal_len+1, buff );
proto_tree_add_text( pt, tvb, var_off, chal_len, "Challenge: %s", buff );
var_off+=chal_len;
tvb_get_nstringz0( tvb, var_off, 16+1, buff );
proto_tree_add_text( pt, tvb, var_off, 16 , "Response: %s", buff );
}
break;
case TAC_PLUS_AUTHEN_TYPE_MSCHAP:
proto_tree_add_text( tree, tvb, AUTHEN_S_DATA_LEN_OFF, 1, "MSCHAP Data Length %d", val );
if( val ) {
proto_item *pi;
proto_tree *pt;
guint8 chal_len=val-(1+49); /* Response field alwayes 49 octets */
pi = proto_tree_add_text(tree, tvb, var_off, val, "MSCHAP Data" );
pt = proto_item_add_subtree( pi, ett_tacplus_body_chap );
val= tvb_get_guint8( tvb, var_off );
proto_tree_add_text( pt, tvb, var_off, 1, "ID: %d", val );
var_off++;
tvb_get_nstringz0( tvb, var_off, chal_len+1, buff );
proto_tree_add_text( pt, tvb, var_off, chal_len, "Challenge: %s", buff );
var_off+=chal_len;
tvb_get_nstringz0( tvb, var_off, 49+1, buff );
proto_tree_add_text( pt, tvb, var_off, 49 , "Response: %s", buff );
}
break;
case TAC_PLUS_AUTHEN_TYPE_ARAP:
proto_tree_add_text( tree, tvb, AUTHEN_S_DATA_LEN_OFF, 1, "ARAP Data Length %d", val );
if( val ) {
proto_item *pi;
proto_tree *pt;
pi = proto_tree_add_text(tree, tvb, var_off, val, "ARAP Data" );
pt = proto_item_add_subtree( pi, ett_tacplus_body_chap );
tvb_get_nstringz0( tvb, var_off, 8+1, buff );
proto_tree_add_text( pt, tvb, var_off, 8, "Nas Challenge: %s", buff );
var_off+=8;
tvb_get_nstringz0( tvb, var_off, 8+1, buff );
proto_tree_add_text( pt, tvb, var_off, 8, "Remote Challenge: %s", buff );
var_off+=8;
tvb_get_nstringz0( tvb, var_off, 8+1, buff );
proto_tree_add_text( pt, tvb, var_off, 8, "Remote Response: %s", buff );
var_off+=8;
}
break;
default: /* Should not be reached */
proto_tree_add_text( tree, tvb, AUTHEN_S_DATA_LEN_OFF, 1, "Data: %d", val );
if( val ){
proto_tree_add_text( tree, tvb, var_off, val, "Data" );
}
}
}
static void
dissect_tacplus_body_authen_req( tvbuff_t* tvb, proto_tree *tree )
{
guint8 val;
int var_off=AUTHEN_S_VARDATA_OFF;
/* Action */
val=tvb_get_guint8( tvb, AUTHEN_S_ACTION_OFF );
proto_tree_add_text( tree, tvb,
AUTHEN_S_ACTION_OFF, 1,
"Action: %s",
val_to_str( val, tacplus_authen_action_vals, "Unknown Packet" ) );
var_off=proto_tree_add_tacplus_common_fields( tvb, tree , AUTHEN_S_PRIV_LVL_OFF, AUTHEN_S_VARDATA_OFF );
switch( val ) {
case TAC_PLUS_AUTHEN_LOGIN:
dissect_tacplus_body_authen_req_login( tvb, tree, var_off );
break;
case TAC_PLUS_AUTHEN_SENDAUTH:
break;
}
}
static void
dissect_tacplus_body_authen_req_cont( tvbuff_t *tvb, proto_tree *tree )
{
int val;
int var_off=AUTHEN_C_VARDATA_OFF;
guint8 *buff=NULL;
val=tvb_get_guint8( tvb, AUTHEN_C_FLAGS_OFF );
proto_tree_add_text( tree, tvb,
AUTHEN_R_FLAGS_OFF, 1, "Flags: 0x%02x %s",
val,
(val&TAC_PLUS_CONTINUE_FLAG_ABORT?"(Abort)":"") );
val=tvb_get_ntohs( tvb, AUTHEN_C_USER_LEN_OFF );
proto_tree_add_text( tree, tvb, AUTHEN_C_USER_LEN_OFF, 2 , "User length: %d", val );
if( val ){
buff=tvb_get_string( tvb, var_off, val );
proto_tree_add_text( tree, tvb, var_off, val, "User: %s", buff );
var_off+=val;
g_free(buff);
}
val=tvb_get_ntohs( tvb, AUTHEN_C_DATA_LEN_OFF );
proto_tree_add_text( tree, tvb, AUTHEN_C_DATA_LEN_OFF, 2 ,
"Data length: %d", val );
if( val ){
proto_tree_add_text( tree, tvb, var_off, val, "Data" );
}
}
/* Server REPLY */
static void
dissect_tacplus_body_authen_rep( tvbuff_t *tvb, proto_tree *tree )
{
int val;
int var_off=AUTHEN_R_VARDATA_OFF;
guint8 *buff=NULL;
val=tvb_get_guint8( tvb, AUTHEN_R_STATUS_OFF );
proto_tree_add_text(tree, tvb,
AUTHEN_R_STATUS_OFF, 1, "Status: 0x%01x (%s)", val,
val_to_str( val, tacplus_reply_status_vals, "Unknown Packet" ) );
val=tvb_get_guint8( tvb, AUTHEN_R_FLAGS_OFF );
proto_tree_add_text(tree, tvb,
AUTHEN_R_FLAGS_OFF, 1, "Flags: 0x%02x %s",
val, (val&TAC_PLUS_REPLY_FLAG_NOECHO?"(NoEcho)":"") );
val=tvb_get_ntohs(tvb, AUTHEN_R_SRV_MSG_LEN_OFF );
proto_tree_add_text( tree, tvb, AUTHEN_R_SRV_MSG_LEN_OFF, 2 ,
"Server message length: %d", val );
if( val ) {
buff=tvb_get_string(tvb, var_off, val );
proto_tree_add_text(tree, tvb, var_off, val, "Server message: %s", buff );
var_off+=val;
g_free(buff);
}
val=tvb_get_ntohs(tvb, AUTHEN_R_DATA_LEN_OFF );
proto_tree_add_text( tree, tvb, AUTHEN_R_DATA_LEN_OFF, 2 ,
"Data length: %d", val );
if( val ){
proto_tree_add_text(tree, tvb, var_off, val, "Data" );
}
}
static void
dissect_tacplus_body_author_req( tvbuff_t* tvb, proto_tree *tree )
{
int val;
int var_off;
val=tvb_get_guint8( tvb, AUTHOR_Q_AUTH_METH_OFF ) ;
proto_tree_add_text( tree, tvb, AUTHOR_Q_AUTH_METH_OFF, 1,
"Auth Method: %s", val_to_str( val, tacplus_authen_method, "Unknown Authen Method" ) );
val=tvb_get_guint8( tvb, AUTHOR_Q_ARGC_OFF );
var_off=proto_tree_add_tacplus_common_fields( tvb, tree ,
AUTHOR_Q_PRIV_LVL_OFF,
AUTHOR_Q_VARDATA_OFF + val );
proto_tree_add_text( tree, tvb, AUTHOR_Q_ARGC_OFF, 1, "Arg count: %d", val );
/* var_off points after rem_addr */
dissect_tacplus_args_list( tvb, tree, var_off, AUTHOR_Q_VARDATA_OFF, val );
}
static void
dissect_tacplus_body_author_rep( tvbuff_t* tvb, proto_tree *tree )
{
int offset=AUTHOR_R_VARDATA_OFF;
int val=tvb_get_guint8( tvb, AUTHOR_R_STATUS_OFF ) ;
proto_tree_add_text( tree, tvb, AUTHOR_R_STATUS_OFF , 1,
"Auth Status: 0x%01x (%s)", val,
val_to_str( val, tacplus_author_status, "Unknown Authorization Status" ));
val=tvb_get_ntohs( tvb, AUTHOR_R_SRV_MSG_LEN_OFF );
offset+=val;
proto_tree_add_text( tree, tvb, AUTHOR_R_SRV_MSG_LEN_OFF, 2, "Server Msg length: %d", val );
val=tvb_get_ntohs( tvb, AUTHOR_R_DATA_LEN_OFF );
offset+=val;
proto_tree_add_text( tree, tvb, AUTHOR_R_DATA_LEN_OFF, 2, "Data length: %d", val );
val=tvb_get_guint8( tvb, AUTHOR_R_ARGC_OFF);
offset+=val;
proto_tree_add_text( tree, tvb, AUTHOR_R_ARGC_OFF, 1, "Arg count: %d", val );
dissect_tacplus_args_list( tvb, tree, offset, AUTHOR_R_VARDATA_OFF, val );
}
static void
dissect_tacplus_body_acct_req( tvbuff_t* tvb, proto_tree *tree )
{
int val, var_off;
proto_item *tf;
proto_tree *flags_tree;
val=tvb_get_guint8( tvb, ACCT_Q_FLAGS_OFF );
tf = proto_tree_add_uint( tree, hf_tacplus_acct_flags, tvb, ACCT_Q_FLAGS_OFF, 1, val );
flags_tree = proto_item_add_subtree( tf, ett_tacplus_acct_flags );
proto_tree_add_text( flags_tree, tvb, ACCT_Q_FLAGS_OFF, 1, "%s",
decode_boolean_bitfield( val, TAC_PLUS_ACCT_FLAG_MORE, 8,
"More: Set", "More: Not set" ) );
proto_tree_add_text( flags_tree, tvb, ACCT_Q_FLAGS_OFF, 1, "%s",
decode_boolean_bitfield( val, TAC_PLUS_ACCT_FLAG_START, 8,
"Start: Set", "Start: Not set" ) );
proto_tree_add_text( flags_tree, tvb, ACCT_Q_FLAGS_OFF, 1, "%s",
decode_boolean_bitfield( val, TAC_PLUS_ACCT_FLAG_STOP, 8,
"Stop: Set", "Stop: Not set" ) );
proto_tree_add_text( flags_tree, tvb, ACCT_Q_FLAGS_OFF, 1, "%s",
decode_boolean_bitfield( val, TAC_PLUS_ACCT_FLAG_WATCHDOG, 8,
"Watchdog: Set", "Watchdog: Not set" ) );
val=tvb_get_guint8( tvb, ACCT_Q_METHOD_OFF );
proto_tree_add_text( tree, tvb, ACCT_Q_METHOD_OFF, 1,
"Authen Method: 0x%01x (%s)",
val, val_to_str( val, tacplus_authen_method, "Unknown Authen Method" ) );
val=tvb_get_guint8( tvb, ACCT_Q_ARG_CNT_OFF );
/* authen_type */
var_off=proto_tree_add_tacplus_common_fields( tvb, tree ,
ACCT_Q_PRIV_LVL_OFF,
ACCT_Q_VARDATA_OFF+val
);
proto_tree_add_text( tree, tvb, ACCT_Q_ARG_CNT_OFF, 1,
"Arg Cnt: %d", val );
dissect_tacplus_args_list( tvb, tree, var_off, ACCT_Q_VARDATA_OFF, val );
}
static void
dissect_tacplus_body_acct_rep( tvbuff_t* tvb, proto_tree *tree )
{
int val, var_off=ACCT_Q_VARDATA_OFF;
guint8 *buff=NULL;
/* Status */
val=tvb_get_guint8( tvb, ACCT_R_STATUS_OFF );
proto_tree_add_text( tree, tvb, ACCT_R_STATUS_OFF, 1, "Status: 0x%02x (%s)", val,
val_to_str( val, tacplus_acct_status, "Bogus status..") );
/* Server Message */
val=tvb_get_ntohs( tvb, ACCT_R_SRV_MSG_LEN_OFF );
proto_tree_add_text( tree, tvb, ACCT_R_SRV_MSG_LEN_OFF, 2 ,
"Server message length: %d", val );
if( val ) {
buff=tvb_get_string( tvb, var_off, val );
proto_tree_add_text( tree, tvb, var_off,
val, "Server message: %s", buff );
var_off+=val;
g_free(buff);
}
/* Data */
val=tvb_get_ntohs( tvb, ACCT_R_DATA_LEN_OFF );
proto_tree_add_text( tree, tvb, ACCT_R_DATA_LEN_OFF, 2 ,
"Data length: %d", val );
if( val ) {
buff= tvb_get_string( tvb, var_off, val );
proto_tree_add_text( tree, tvb, var_off,
val, "Data: %s", buff );
g_free(buff);
}
}
static void
dissect_tacplus_body(tvbuff_t * hdr_tvb, tvbuff_t * tvb, proto_tree * tree )
{
int type = tvb_get_guint8( hdr_tvb, H_TYPE_OFF );
int seq_no = tvb_get_guint8( hdr_tvb, H_SEQ_NO_OFF );
switch (type) {
case TAC_PLUS_AUTHEN:
if ( seq_no & 0x01) {
if ( seq_no == 1 )
dissect_tacplus_body_authen_req( tvb, tree );
else
dissect_tacplus_body_authen_req_cont( tvb, tree );
} else {
dissect_tacplus_body_authen_rep( tvb, tree );
}
return;
break;
case TAC_PLUS_AUTHOR:
if ( seq_no & 0x01)
dissect_tacplus_body_author_req( tvb, tree );
else
dissect_tacplus_body_author_rep( tvb, tree );
return;
break;
case TAC_PLUS_ACCT:
if ( seq_no & 0x01)
dissect_tacplus_body_acct_req( tvb, tree );
else
dissect_tacplus_body_acct_rep( tvb, tree );
return;
break;
}
proto_tree_add_text( tree, tvb, 0, tvb_length( tvb ), "Bogus..");
}
#ifdef DEB_TACPLUS
static void
tacplus_print_key_entry( gpointer data, gpointer user_data )
{
tacplus_key_entry *tacplus_data=(tacplus_key_entry *)data;
if( user_data ) {
printf("%s:%s=%s\n", address_to_str( tacplus_data->s ),
address_to_str( tacplus_data->c ), tacplus_data->k );
} else {
printf("%s:%s\n", address_to_str( tacplus_data->s ),
address_to_str( tacplus_data->c ) );
}
}
#endif
static int
cmp_conv_address( gconstpointer p1, gconstpointer p2 )
{
tacplus_key_entry *a1=(tacplus_key_entry*)p1;
tacplus_key_entry *a2=(tacplus_key_entry*)p2;
gint32 ret;
/*
printf("p1=>");
tacplus_print_key_entry( p1, NULL );
printf("p2=>");
tacplus_print_key_entry( p2, NULL );
*/
ret=CMP_ADDRESS( a1->s, a2->s );
if( !ret ) {
ret=CMP_ADDRESS( a1->c, a2->c );
/*
if(ret)
printf("No Client found!"); */
} else {
/* printf("No Server found!"); */
}
return ret;
}
static char*
find_key( address *srv, address *cln )
{
tacplus_key_entry data;
GSList *match;
data.s=srv;
data.c=cln;
/* printf("Looking for: ");
tacplus_print_key_entry( (gconstpointer)&data, NULL ); */
match=g_slist_find_custom( tacplus_keys, (gpointer)&data, cmp_conv_address );
/* printf("Finished (%p)\n", match); */
if( match )
return ((tacplus_key_entry*)match->data)->k;
return (tacplus_keys?NULL:tacplus_opt_key);
}
#define AF_INET 2
int inet_pton(int , const char*, void*);
static void
mkipv4_address( address **addr, char *str_addr )
{
*addr=g_malloc( sizeof(address) );
(*addr)->type=AT_IPv4;
(*addr)->len=4;
(*addr)->data=g_malloc( 4 );
inet_pton( AF_INET, (const char*)str_addr, (void*)(*addr)->data );
}
static void
parse_tuple( char *key_from_option )
{
char *client,*key;
tacplus_key_entry *tacplus_data=g_malloc( sizeof(tacplus_key_entry) );
/*
printf("keys: %s\n", key_from_option );
*/
client=strchr(key_from_option,'/');
if(!client)
return;
*client++='\0';
key=strchr(client,'=');
if(!key)
return;
*key++='\0';
/*
printf("%s %s => %s\n", key_from_option, client, key );
*/
mkipv4_address( &tacplus_data->s, key_from_option );
mkipv4_address( &tacplus_data->c, client );
tacplus_data->k=strdup( key );
tacplus_keys = g_slist_prepend( tacplus_keys, tacplus_data );
}
static
void
free_tacplus_keys( gpointer data, gpointer user_data _U_ )
{
g_free( ((tacplus_key_entry *)data)->k );
}
static
void
parse_tacplus_keys( char *keys_from_option )
{
char *s1,*s;
/* Drop old keys */
if( tacplus_keys ) {
g_slist_foreach( tacplus_keys, free_tacplus_keys, NULL );
g_slist_free( tacplus_keys );
tacplus_keys=NULL;
}
if( !strchr( keys_from_option, '/' ) ){
/* option not in client/server=key format */
return ;
}
s=strdup(keys_from_option);
s1=s;
keys_from_option = s;
while(keys_from_option){
if( (s=strchr( keys_from_option, ' ' )) != NULL )
*s++='\0';
parse_tuple( keys_from_option );
keys_from_option=s;
}
g_free( s1 );
#ifdef DEB_TACPLUS
g_slist_foreach( tacplus_keys, tacplus_print_key_entry, GINT_TO_POINTER(1) );
#endif
}
static void
dissect_tacplus(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
tvbuff_t *new_tvb=NULL;
proto_tree *tacplus_tree;
proto_item *ti;
guint8 version,flags;
proto_tree *flags_tree;
proto_item *tf;
proto_item *tmp_pi;
guint32 len;
gboolean request=( pinfo->destport == TCP_PORT_TACACS );
char *key=NULL;
if( request ) {
key=find_key( &pinfo->dst, &pinfo->src );
} else {
key=find_key( &pinfo->src, &pinfo->dst );
}
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "TACACS+");
if (check_col(pinfo->cinfo, COL_INFO))
{
int type = tvb_get_guint8(tvb,1);
col_add_fstr( pinfo->cinfo, COL_INFO, "%s: %s",
request ? "Q" : "R",
val_to_str(type, tacplus_type_vals, "Unknown (0x%02x)"));
}
if (tree)
{
ti = proto_tree_add_protocol_format(tree, proto_tacplus,
tvb, 0, -1, "TACACS+");
tacplus_tree = proto_item_add_subtree(ti, ett_tacplus);
if (pinfo->match_port == pinfo->destport)
{
proto_tree_add_boolean_hidden(tacplus_tree,
hf_tacplus_request, tvb, 0, 0, TRUE);
}
else
{
proto_tree_add_boolean_hidden(tacplus_tree,
hf_tacplus_response, tvb, 0, 0, TRUE);
}
version = tvb_get_guint8(tvb,0);
proto_tree_add_uint_format(tacplus_tree, hf_tacplus_majvers, tvb, 0, 1,
version,
"Major version: %s",
(version&0xf0)==0xc0?"TACACS+":"Unknown Version");
proto_tree_add_uint(tacplus_tree, hf_tacplus_minvers, tvb, 0, 1,
version&0xf);
proto_tree_add_item(tacplus_tree, hf_tacplus_type, tvb, 1, 1,
FALSE);
proto_tree_add_item(tacplus_tree, hf_tacplus_seqno, tvb, 2, 1,
FALSE);
flags = tvb_get_guint8(tvb,3);
tf = proto_tree_add_uint_format(tacplus_tree, hf_tacplus_flags,
tvb, 3, 1, flags,
"Flags: 0x%02x (%s payload, %s)",
flags,
(flags&FLAGS_UNENCRYPTED) ? "Unencrypted" :
"Encrypted",
(flags&FLAGS_SINGLE) ? "Single connection" :
"Multiple Connections" );
flags_tree = proto_item_add_subtree(tf, ett_tacplus_flags);
proto_tree_add_boolean(flags_tree, hf_tacplus_flags_payload_type,
tvb, 3, 1, flags);
proto_tree_add_boolean(flags_tree, hf_tacplus_flags_connection_type,
tvb, 3, 1, flags);
proto_tree_add_item(tacplus_tree, hf_tacplus_session_id, tvb, 4, 4,
FALSE);
len = tvb_get_ntohl(tvb,8);
proto_tree_add_uint(tacplus_tree, hf_tacplus_packet_len, tvb, 8, 4,
len);
tmp_pi = proto_tree_add_text(tacplus_tree, tvb, TAC_PLUS_HDR_SIZE, len, "%s%s",
((flags&FLAGS_UNENCRYPTED)?"":"Encrypted "), request?"Request":"Reply" );
if( flags&FLAGS_UNENCRYPTED ) {
new_tvb = tvb_new_subset( tvb, TAC_PLUS_HDR_SIZE, len, len );
} else {
new_tvb=NULL;
if( key && *key ){
tacplus_decrypted_tvb_setup( tvb, &new_tvb, pinfo, len, version, key );
}
}
if( new_tvb ) {
/* Check to see if I've a decrypted tacacs packet */
if( !(flags&FLAGS_UNENCRYPTED) ){
tmp_pi = proto_tree_add_text(tacplus_tree, new_tvb, 0, len, "Decrypted %s",
request?"Request":"Reply" );
}
dissect_tacplus_body( tvb, new_tvb, proto_item_add_subtree( tmp_pi, ett_tacplus_body ));
}
}
}
void
tacplus_pref_cb(void)
{
parse_tacplus_keys( tacplus_opt_key );
}
void
proto_register_tacplus(void)
{
static hf_register_info hf[] = {
{ &hf_tacplus_response,
{ "Response", "tacplus.response",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"TRUE if TACACS+ response", HFILL }},
{ &hf_tacplus_request,
{ "Request", "tacplus.request",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"TRUE if TACACS+ request", HFILL }},
{ &hf_tacplus_majvers,
{ "Major version", "tacplus.majvers",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Major version number", HFILL }},
{ &hf_tacplus_minvers,
{ "Minor version", "tacplus.minvers",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Minor version number", HFILL }},
{ &hf_tacplus_type,
{ "Type", "tacplus.type",
FT_UINT8, BASE_DEC, VALS(tacplus_type_vals), 0x0,
"Type", HFILL }},
{ &hf_tacplus_seqno,
{ "Sequence number", "tacplus.seqno",
FT_UINT8, BASE_DEC, NULL, 0x0,
"Sequence number", HFILL }},
{ &hf_tacplus_flags,
{ "Flags", "tacplus.flags",
FT_UINT8, BASE_HEX, NULL, 0x0,
"Flags", HFILL }},
{ &hf_tacplus_flags_payload_type,
{ "Unencrypted", "tacplus.flags.unencrypted",
FT_BOOLEAN, 8, TFS(&flags_set_truth), FLAGS_UNENCRYPTED,
"Is payload unencrypted?", HFILL }},
{ &hf_tacplus_flags_connection_type,
{ "Single Connection", "tacplus.flags.singleconn",
FT_BOOLEAN, 8, TFS(&flags_set_truth), FLAGS_SINGLE,
"Is this a single connection?", HFILL }},
{ &hf_tacplus_acct_flags,
{ "Flags", "tacplus.acct.flags",
FT_UINT8, BASE_HEX, NULL, 0x0,
"Flags", HFILL }},
{ &hf_tacplus_session_id,
{ "Session ID", "tacplus.session_id",
FT_UINT32, BASE_DEC, NULL, 0x0,
"Session ID", HFILL }},
{ &hf_tacplus_packet_len,
{ "Packet length", "tacplus.packet_len",
FT_UINT32, BASE_DEC, NULL, 0x0,
"Packet length", HFILL }}
};
static gint *ett[] = {
&ett_tacplus,
&ett_tacplus_flags,
&ett_tacplus_acct_flags,
&ett_tacplus_body,
&ett_tacplus_body_chap,
};
module_t *tacplus_module;
proto_tacplus = proto_register_protocol("TACACS+", "TACACS+", "tacplus");
proto_register_field_array(proto_tacplus, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
tacplus_module = prefs_register_protocol (proto_tacplus, tacplus_pref_cb );
prefs_register_string_preference ( tacplus_module, "key",
"TACACS+ Encryption Key", "TACACS+ Encryption Key", &tacplus_opt_key );
}
void
proto_reg_handoff_tacplus(void)
{
dissector_handle_t tacplus_handle;
tacplus_handle = create_dissector_handle(dissect_tacplus,
proto_tacplus);
dissector_add("tcp.port", TCP_PORT_TACACS, tacplus_handle);
}
#define MD5_LEN 16
static void
md5_xor( guint8 *data, char *key, int data_len, guint8 *session_id, guint8 version, guint8 seq_no )
{
int i,j,md5_len;
md5_byte_t *md5_buff;
md5_byte_t hash[MD5_LEN]; /* the md5 hash */
md5_byte_t *mdp;
md5_state_t mdcontext;
md5_len = 4 /* sizeof(session_id) */ + strlen(key)
+ sizeof(version) + sizeof(seq_no);
md5_buff = (md5_byte_t*)g_malloc(md5_len+MD5_LEN);
mdp = md5_buff;
*(guint32*)mdp = *(guint32*)session_id;
mdp += 4 ;
memcpy(mdp, key, strlen(key));
mdp += strlen(key);
*mdp++ = version;
*mdp++ = seq_no;
md5_init(&mdcontext);
md5_append(&mdcontext, md5_buff, md5_len);
md5_finish(&mdcontext,hash);
md5_len += MD5_LEN;
for (i = 0; i < data_len; i += 16) {
for (j = 0; j < 16; j++) {
if ((i + j) >= data_len) {
i = data_len+1; /* To exit from the external loop */
break;
}
data[i + j] ^= hash[j];
}
memcpy(mdp, hash, MD5_LEN);
md5_init(&mdcontext);
md5_append(&mdcontext, md5_buff, md5_len);
md5_finish(&mdcontext,hash);
}
g_free( md5_buff );
}
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