forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
"tvb_memcpy()"ing to it, and putting in a null terminator; "tvb_get_string()" will check whether all bytes of the string are present before allocating the buffer, so that you don't leak memory if the copy throws an exception, and don't crash if the length is absurdly large. Use "tvb_memdup()" instead of allocating a buffer and "tvb_memcpy()"ing to it, so that an exception is thrown before you try to allocate the buffer (for the same reasons as listed above). Before allocating a buffer used when processing a chunk of data from a packet, get a pointer to the chunk with "tvb_get_ptr()", or check that the data is all there with "tvb_ensure_bytes_exist()", so that an exception is thrown before you try to allocate the buffer (for the same reasons as listed above). Fix up the lengths of the tvbuff used when dissecting ONC RPC opaque data with a particular dissector. svn path=/trunk/; revision=10236
521 lines
14 KiB
C
521 lines
14 KiB
C
/* packet-xdmcp.c
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* Routines for XDMCP message dissection
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* Copyright 2002, Pasi Eronen <pasi.eronen@nixu.com>
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*
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* $Id: packet-xdmcp.c,v 1.5 2004/02/25 09:31:07 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <string.h>
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#include <glib.h>
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#include <epan/packet.h>
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#define UDP_PORT_XDMCP 177
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#define XDMCP_PROTOCOL_VERSION 1
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#define XDMCP_BROADCAST_QUERY 1
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#define XDMCP_QUERY 2
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#define XDMCP_INDIRECT_QUERY 3
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#define XDMCP_FORWARD_QUERY 4
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#define XDMCP_WILLING 5
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#define XDMCP_UNWILLING 6
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#define XDMCP_REQUEST 7
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#define XDMCP_ACCEPT 8
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#define XDMCP_DECLINE 9
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#define XDMCP_MANAGE 10
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#define XDMCP_REFUSE 11
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#define XDMCP_FAILED 12
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#define XDMCP_KEEPALIVE 13
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#define XDMCP_ALIVE 14
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static const value_string opcode_vals[] = {
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{ XDMCP_BROADCAST_QUERY, "Broadcast_query" },
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{ XDMCP_QUERY, "Query" },
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{ XDMCP_INDIRECT_QUERY, "Indirect_query" },
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{ XDMCP_FORWARD_QUERY, "Forward_query" },
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{ XDMCP_WILLING, "Willing" },
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{ XDMCP_UNWILLING, "Unwilling" },
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{ XDMCP_REQUEST, "Request" },
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{ XDMCP_ACCEPT, "Accept "},
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{ XDMCP_DECLINE, "Decline" },
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{ XDMCP_MANAGE, "Manage" },
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{ XDMCP_REFUSE, "Refuse" },
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{ XDMCP_FAILED, "Failed" },
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{ XDMCP_KEEPALIVE, "Keepalive" },
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{ XDMCP_ALIVE, "Alive" },
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{ 0, NULL }
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};
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/* Copied from packet-x11.c */
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static const value_string family_vals[] = {
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{ 0, "Internet" },
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{ 1, "DECnet" },
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{ 2, "Chaos" },
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{ 0, NULL }
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};
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static gint proto_xdmcp = -1;
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static gint hf_xdmcp_version = -1;
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static gint hf_xdmcp_opcode = -1;
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static gint hf_xdmcp_length = -1;
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static gint hf_xdmcp_authentication_name = -1;
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static gint hf_xdmcp_authorization_name = -1;
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static gint hf_xdmcp_hostname = -1;
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static gint hf_xdmcp_status = -1;
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static gint hf_xdmcp_session_id = -1;
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static gint hf_xdmcp_display_number = -1;
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static gint ett_xdmcp = -1;
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static gint ett_xdmcp_authorization_names = -1;
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static gint ett_xdmcp_connections = -1;
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static gint ett_xdmcp_connection = -1;
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/* Copied from packet-x11.c */
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static void stringCopy(char *dest, const char *source, int length)
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{
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guchar c;
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while(length--) {
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c = *source++;
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if (!isgraph(c) && c != ' ') c = '.';
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*dest++ = c;
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}
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*dest++ = '\0';
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}
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static gint xdmcp_add_string(proto_tree *tree, gint hf,
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tvbuff_t *tvb, gint offset)
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{
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const guint8 *p;
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char *str;
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guint len;
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len = tvb_get_ntohs(tvb, offset);
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p = tvb_get_ptr(tvb, offset+2, len);
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str = g_malloc(len+1);
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stringCopy(str, p, len);
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proto_tree_add_string(tree, hf, tvb, offset, len+2, str);
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g_free(str);
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return len+2;
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}
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static gint xdmcp_add_text(proto_tree *tree, const char *text,
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tvbuff_t *tvb, gint offset)
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{
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const guint8 *p;
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char *str;
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guint len;
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len = tvb_get_ntohs(tvb, offset);
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p = tvb_get_ptr(tvb, offset+2, len);
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str = g_malloc(len+1);
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stringCopy(str, p, len);
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proto_tree_add_text(tree, tvb, offset, len+2, "%s: %s", text, str);
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g_free(str);
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return len+2;
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}
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static gint xdmcp_add_bytes(proto_tree *tree, const char *text,
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tvbuff_t *tvb, gint offset)
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{
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guint len;
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len = tvb_get_ntohs(tvb, offset);
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proto_tree_add_text(tree, tvb, offset, len+2,
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"%s (%u byte%s)", text, len, plurality(len, "", "s"));
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return len+2;
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}
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static gint xdmcp_add_authorization_names(proto_tree *tree,
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tvbuff_t *tvb, gint offset)
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{
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proto_tree *anames_tree;
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proto_item *anames_ti;
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gint anames_len, anames_start_offset;
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anames_start_offset = offset;
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anames_len = tvb_get_guint8(tvb, offset);
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anames_ti = proto_tree_add_text(tree, tvb,
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anames_start_offset, -1,
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"Authorization names (%d)",
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anames_len);
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anames_tree = proto_item_add_subtree(anames_ti,
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ett_xdmcp_authorization_names);
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anames_len = tvb_get_guint8(tvb, offset);
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offset++;
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while (anames_len > 0) {
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offset += xdmcp_add_string(anames_tree, hf_xdmcp_authorization_name,
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tvb, offset);
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anames_len--;
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}
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proto_item_set_len(anames_ti, offset - anames_start_offset);
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return offset - anames_start_offset;
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}
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/*
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* I didn't find any documentation for the XDMCP protocol, so
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* this is reverse-engineered from XFree86 source files
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* xc/programs/xdm/xdmcp.c and xc/programs/Xserver/os/xdmcp.c.
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*/
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static void dissect_xdmcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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gint version = -1, opcode = -1;
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gint offset = 0;
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proto_item *ti;
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proto_tree *xdmcp_tree = 0;
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version = tvb_get_ntohs(tvb, offset);
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if (version != XDMCP_PROTOCOL_VERSION) {
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/* Only version 1 exists, so this probably is not XDMCP at all... */
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return;
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}
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "XDMCP");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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if (tree) {
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ti = proto_tree_add_item(tree, proto_xdmcp, tvb, offset, -1, FALSE);
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xdmcp_tree = proto_item_add_subtree(ti, ett_xdmcp);
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proto_tree_add_uint(xdmcp_tree, hf_xdmcp_version, tvb,
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offset, 2, version);
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}
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offset += 2;
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opcode = tvb_get_ntohs(tvb, offset);
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if (tree) {
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proto_tree_add_uint(xdmcp_tree, hf_xdmcp_opcode, tvb,
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offset, 2, opcode);
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}
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offset += 2;
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_add_fstr(pinfo->cinfo, COL_INFO, "%s",
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val_to_str(opcode, opcode_vals, "Unknown (0x%04x)"));
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}
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if (tree) {
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_length, tvb,
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offset, 2, FALSE);
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offset += 2;
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switch (opcode) {
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case XDMCP_FORWARD_QUERY:
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{
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gint alen, plen;
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alen = tvb_get_ntohs(tvb, offset);
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/* I have never seen anything except IPv4 addresses here,
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* but in theory the protocol should support other address
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* families. */
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if (alen == 4) {
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proto_tree_add_text(xdmcp_tree, tvb, offset, alen+2,
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"Client address: %s",
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ip_to_str(tvb_get_ptr(tvb, offset+2, 4)));
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offset += 6;
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} else {
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offset += xdmcp_add_bytes(xdmcp_tree, "Client address", tvb, offset);
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}
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plen = tvb_get_ntohs(tvb, offset);
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if (plen == 2) {
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proto_tree_add_text(xdmcp_tree, tvb, offset, plen+2,
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"Client port: %u",
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tvb_get_ntohs(tvb, offset+2));
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offset += 4;
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} else {
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offset += xdmcp_add_bytes(xdmcp_tree, "Client port", tvb, offset);
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}
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}
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/* fall-through */
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case XDMCP_BROADCAST_QUERY:
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case XDMCP_QUERY:
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case XDMCP_INDIRECT_QUERY:
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offset += xdmcp_add_authorization_names(xdmcp_tree, tvb, offset);
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break;
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case XDMCP_WILLING:
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_authentication_name,
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tvb, offset);
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_hostname,
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tvb, offset);
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_status,
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tvb, offset);
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break;
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case XDMCP_UNWILLING:
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_hostname,
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tvb, offset);
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_status,
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tvb, offset);
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break;
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case XDMCP_REQUEST:
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{
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proto_tree *clist_tree;
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proto_item *clist_ti;
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gint ctypes_len, caddrs_len, n;
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gint ctypes_start_offset, caddrs_offset;
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_display_number, tvb,
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offset, 2, FALSE);
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offset += 2;
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ctypes_len = tvb_get_guint8(tvb, offset);
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ctypes_start_offset = offset;
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caddrs_offset = offset + 1 + 2*ctypes_len;
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caddrs_len = tvb_get_guint8(tvb, caddrs_offset);
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if (ctypes_len != caddrs_len) {
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proto_tree_add_text(xdmcp_tree, NULL, 0, 0,
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"Error: Connection type/address arrays don't match");
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return;
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}
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clist_ti = proto_tree_add_text(xdmcp_tree,
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tvb, ctypes_start_offset, -1,
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"Connections (%d)",
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ctypes_len);
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clist_tree = proto_item_add_subtree(clist_ti, ett_xdmcp_connections);
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offset++;
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caddrs_offset++;
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n = 1;
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while (ctypes_len > 0) {
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proto_item *connection_ti;
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proto_tree *connection_tree;
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const char *ip_string;
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gint alen;
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gint ctype = tvb_get_ntohs(tvb, offset);
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offset += 2;
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alen = tvb_get_ntohs(tvb, caddrs_offset);
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caddrs_offset += 2;
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if ((ctype == 0) && (alen == 4)) {
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ip_string = ip_to_str(tvb_get_ptr(tvb, caddrs_offset, 4));
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} else {
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ip_string = NULL;
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}
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connection_ti = proto_tree_add_text(clist_tree, NULL, 0, 0,
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"Connection %d%s%s", n,
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(ip_string ? ": " : ""),
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(ip_string ? ip_string : ""));
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connection_tree = proto_item_add_subtree(connection_ti,
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ett_xdmcp_connection);
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proto_tree_add_text(connection_tree, tvb, offset-2, 2,
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"Type: %s",
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val_to_str(ctype, family_vals,
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"Unknown (0x%04x)"));
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if ((ctype == 0) && (alen == 4)) {
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proto_tree_add_text(connection_tree, tvb, caddrs_offset-2, alen+2,
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"Address: %s", ip_string);
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} else {
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proto_tree_add_text(connection_tree, tvb, caddrs_offset-2, alen+2,
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"Address: (%u byte%s)", alen,
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plurality(alen, "", "s"));
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}
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caddrs_offset += alen;
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ctypes_len--;
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n++;
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}
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offset = caddrs_offset;
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proto_item_set_len(clist_ti, offset - ctypes_start_offset);
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_authentication_name,
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tvb, offset);
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offset += xdmcp_add_bytes(xdmcp_tree, "Authentication data",
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tvb, offset);
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offset += xdmcp_add_authorization_names(xdmcp_tree, tvb, offset);
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offset += xdmcp_add_text(xdmcp_tree, "Manufacturer display ID",
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tvb, offset);
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break;
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}
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case XDMCP_ACCEPT:
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_session_id, tvb,
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offset, 4, FALSE);
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offset += 4;
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_authentication_name,
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tvb, offset);
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offset += xdmcp_add_bytes(xdmcp_tree, "Authentication data",
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tvb, offset);
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_authorization_name,
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tvb, offset);
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offset += xdmcp_add_bytes(xdmcp_tree, "Authorization data",
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tvb, offset);
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break;
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case XDMCP_DECLINE:
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_status,
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tvb, offset);
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_authentication_name,
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tvb, offset);
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offset += xdmcp_add_bytes(xdmcp_tree, "Authentication data",
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tvb, offset);
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break;
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case XDMCP_MANAGE:
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_session_id, tvb,
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offset, 4, FALSE);
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offset += 4;
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_display_number, tvb,
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offset, 2, FALSE);
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offset += 2;
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offset += xdmcp_add_text(xdmcp_tree, "Display class",
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tvb, offset);
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break;
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case XDMCP_REFUSE:
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_session_id, tvb,
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offset, 4, FALSE);
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offset += 4;
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break;
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case XDMCP_FAILED:
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_session_id, tvb,
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offset, 4, FALSE);
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offset += 4;
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offset += xdmcp_add_string(xdmcp_tree, hf_xdmcp_status,
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tvb, offset);
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break;
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case XDMCP_KEEPALIVE:
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_display_number, tvb,
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offset, 2, FALSE);
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offset += 2;
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_session_id, tvb,
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offset, 4, FALSE);
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offset += 4;
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break;
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case XDMCP_ALIVE:
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proto_tree_add_text(xdmcp_tree, tvb, offset, 1,
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"Session running: %s",
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(tvb_get_guint8(tvb, offset) ? "Yes" : "No"));
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offset++;
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proto_tree_add_item(xdmcp_tree, hf_xdmcp_session_id, tvb,
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offset, 4, FALSE);
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offset += 4;
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break;
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}
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}
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}
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/* Register the protocol with Ethereal */
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void proto_register_xdmcp(void)
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{
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/* Setup list of header fields */
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static hf_register_info hf[] = {
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{ &hf_xdmcp_version,
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{ "Version", "xdmcp.version",
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FT_UINT16, BASE_DEC, NULL, 0,
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"Protocol version", HFILL }
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},
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{ &hf_xdmcp_opcode,
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{ "Opcode", "xdmcp.opcode",
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FT_UINT16, BASE_HEX, VALS(opcode_vals), 0,
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"Opcode", HFILL }
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},
|
|
{ &hf_xdmcp_length,
|
|
{ "Message length", "xdmcp.length",
|
|
FT_UINT16, BASE_DEC, NULL, 0,
|
|
"Length of the remaining message", HFILL }
|
|
},
|
|
{ &hf_xdmcp_authentication_name,
|
|
{ "Authentication name", "xdmcp.authentication_name",
|
|
FT_STRING, BASE_DEC, NULL, 0,
|
|
"Authentication name", HFILL }
|
|
},
|
|
{ &hf_xdmcp_authorization_name,
|
|
{ "Authorization name", "xdmcp.authorization_name",
|
|
FT_STRING, BASE_DEC, NULL, 0,
|
|
"Authorization name", HFILL }
|
|
},
|
|
{ &hf_xdmcp_hostname,
|
|
{ "Hostname", "xdmcp.hostname",
|
|
FT_STRING, BASE_DEC, NULL, 0,
|
|
"Hostname", HFILL }
|
|
},
|
|
{ &hf_xdmcp_status,
|
|
{ "Status", "xdmcp.status",
|
|
FT_STRING, BASE_DEC, NULL, 0,
|
|
"Status", HFILL }
|
|
},
|
|
{ &hf_xdmcp_session_id,
|
|
{ "Session ID", "xdmcp.session_id",
|
|
FT_UINT32, BASE_HEX, NULL, 0,
|
|
"Session identifier", HFILL }
|
|
},
|
|
{ &hf_xdmcp_display_number,
|
|
{ "Display number", "xdmcp.display_number",
|
|
FT_UINT16, BASE_DEC, NULL, 0,
|
|
"Display number", HFILL }
|
|
},
|
|
};
|
|
|
|
/* Setup protocol subtree array */
|
|
static gint *ett[] = {
|
|
&ett_xdmcp,
|
|
&ett_xdmcp_authorization_names,
|
|
&ett_xdmcp_connections,
|
|
&ett_xdmcp_connection
|
|
};
|
|
|
|
/* Register the protocol name and description */
|
|
proto_xdmcp = proto_register_protocol("X Display Manager Control Protocol",
|
|
"XDMCP", "xdmcp");
|
|
|
|
/* Required function calls to register the header fields and subtrees used */
|
|
proto_register_field_array(proto_xdmcp, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_xdmcp(void)
|
|
{
|
|
dissector_handle_t xdmcp_handle;
|
|
|
|
xdmcp_handle = create_dissector_handle(dissect_xdmcp, proto_xdmcp);
|
|
dissector_add("udp.port", UDP_PORT_XDMCP, xdmcp_handle);
|
|
}
|