![AndersBroman](/assets/img/avatar_default.png)
Change-Id: I859597ebc957a58f659800ef63318f94e80feabf Reviewed-on: https://code.wireshark.org/review/1104 Reviewed-by: Anders Broman <a.broman58@gmail.com>
328 lines
9.5 KiB
C
328 lines
9.5 KiB
C
/* packet-bencode.c
|
|
* Routines for bencode dissection
|
|
* Copyright (C) 2004,2013 Jelmer Vernooij <jelmer@samba.org>
|
|
*
|
|
* Wireshark - Network traffic analyzer
|
|
* By Gerald Combs <gerald@wireshark.org>
|
|
* Copyright 1998 Gerald Combs
|
|
*
|
|
* Copied from packet-pop.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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*/
|
|
|
|
#include "config.h"
|
|
|
|
#include <glib.h>
|
|
#include <epan/prefs.h>
|
|
#include <epan/conversation.h>
|
|
#include <epan/packet.h>
|
|
#include <epan/strutil.h>
|
|
|
|
#include "packet-tcp.h"
|
|
|
|
void proto_register_bencode(void);
|
|
|
|
static int proto_bencode = -1;
|
|
|
|
static gint hf_bencode_str_length = -1;
|
|
static gint hf_bencode_str = -1;
|
|
static gint hf_bencode_int = -1;
|
|
static gint hf_bencode_dict = -1;
|
|
static gint hf_bencode_dict_entry = -1;
|
|
static gint hf_bencode_list = -1;
|
|
|
|
static gint ett_bencode_dict = -1;
|
|
static gint ett_bencode_dict_entry = -1;
|
|
static gint ett_bencode_list = -1;
|
|
|
|
static int dissect_bencoding_str(tvbuff_t *tvb, packet_info *pinfo _U_,
|
|
int offset, int length, proto_tree *tree, proto_item *ti, int treeadd)
|
|
{
|
|
guint8 ch;
|
|
int stringlen = 0, nextstringlen;
|
|
int used;
|
|
int izero = 0;
|
|
|
|
if (length<2) {
|
|
proto_tree_add_text(tree, tvb, offset, length, "Decode Aborted: Invalid String");
|
|
return -1;
|
|
}
|
|
|
|
used = 0;
|
|
|
|
while (length>=1) {
|
|
ch = tvb_get_guint8(tvb, offset+used);
|
|
length--;
|
|
used++;
|
|
|
|
if (ch==':' && used>1) {
|
|
if (stringlen>length || stringlen<0) {
|
|
proto_tree_add_text(tree, tvb, offset, length, "Decode Aborted: Invalid String Length");
|
|
return -1;
|
|
}
|
|
if (tree) {
|
|
proto_tree_add_uint(tree, hf_bencode_str_length, tvb, offset, used, stringlen);
|
|
proto_tree_add_item(tree, hf_bencode_str, tvb, offset+used, stringlen, ENC_ASCII|ENC_NA);
|
|
|
|
if (treeadd==1) {
|
|
proto_item_append_text(ti, " Key: %s", format_text((guchar *)tvb_memdup(wmem_packet_scope(), tvb, offset+used, stringlen), stringlen));
|
|
}
|
|
if (treeadd==2) {
|
|
proto_item_append_text(ti, " Value: %s", format_text((guchar *)tvb_memdup(wmem_packet_scope(), tvb, offset+used, stringlen), stringlen));
|
|
}
|
|
}
|
|
return used+stringlen;
|
|
}
|
|
|
|
if (!izero && ch>='0' && ch<='9') {
|
|
if (ch=='0' && used==1) {
|
|
izero = 1;
|
|
}
|
|
|
|
nextstringlen = (stringlen * 10) + (ch - '0');
|
|
if (nextstringlen>=stringlen) {
|
|
stringlen = nextstringlen;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
proto_tree_add_text(tree, tvb, offset, length, "Decode Aborted: Invalid String");
|
|
return -1;
|
|
}
|
|
|
|
proto_tree_add_text(tree, tvb, offset, length, "Truncated Data");
|
|
return -1;
|
|
}
|
|
|
|
static int dissect_bencoding_int(tvbuff_t *tvb, packet_info *pinfo _U_,
|
|
int offset, int length, proto_tree *tree, proto_item *ti, int treeadd)
|
|
{
|
|
gint32 ival=0;
|
|
int neg = 0;
|
|
int izero = 0;
|
|
int used;
|
|
guint8 ch;
|
|
|
|
if (length<3) {
|
|
proto_tree_add_text(tree, tvb, offset, length, "Decode Aborted: Invalid Integer");
|
|
return -1;
|
|
}
|
|
|
|
length--;
|
|
used = 1;
|
|
|
|
while (length>=1) {
|
|
ch = tvb_get_guint8(tvb, offset+used);
|
|
length--;
|
|
used++;
|
|
|
|
switch (ch) {
|
|
case 'e':
|
|
if (tree) {
|
|
if (neg) ival = -ival;
|
|
proto_tree_add_int(tree, hf_bencode_int, tvb, offset, used, ival);
|
|
if (treeadd==2) {
|
|
proto_item_append_text(ti, " Value: %d", ival);
|
|
}
|
|
}
|
|
return used;
|
|
|
|
case '-':
|
|
if (used==2) {
|
|
neg = 1;
|
|
break;
|
|
}
|
|
/* Fall through */
|
|
|
|
default:
|
|
if (!(ch=='0' && used==3 && neg)) { /* -0 is invalid */
|
|
if (ch=='0' && used==2) { /* as is 0[0-9]+ */
|
|
izero = 1;
|
|
break;
|
|
}
|
|
if (!izero && ch>='0' && ch<='9') {
|
|
ival = (ival * 10) + (ch - '0');
|
|
break;
|
|
}
|
|
}
|
|
|
|
proto_tree_add_text(tree, tvb, offset, length, "Decode Aborted: Invalid Integer");
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
proto_tree_add_text(tree, tvb, offset, length, "Truncated Data");
|
|
return -1;
|
|
}
|
|
|
|
static int dissect_bencoding_rec(tvbuff_t *tvb, packet_info *pinfo _U_,
|
|
int offset, int length, proto_tree *tree, int level, proto_item *treei, int treeadd)
|
|
{
|
|
guint8 op;
|
|
int oplen = 0, op1len, op2len;
|
|
int used;
|
|
|
|
proto_item *ti = NULL, *td = NULL;
|
|
proto_tree *itree = NULL, *dtree = NULL;
|
|
|
|
if (level>10) {
|
|
proto_tree_add_text(tree, tvb, offset, -1, "Decode Aborted: Nested Too Deep");
|
|
return -1;
|
|
}
|
|
if (length<1) {
|
|
proto_tree_add_text(tree, tvb, offset, -1, "Truncated Data");
|
|
return length;
|
|
}
|
|
|
|
op = tvb_get_guint8(tvb, offset);
|
|
if (tree) {
|
|
oplen = dissect_bencoding_rec(tvb, pinfo, offset, length, NULL, level, NULL, 0);
|
|
if (oplen<0) oplen = length;
|
|
}
|
|
|
|
switch (op) {
|
|
case 'd':
|
|
if (tree) {
|
|
td = proto_tree_add_item(tree, hf_bencode_dict, tvb, offset, oplen, ENC_NA);
|
|
dtree = proto_item_add_subtree(td, ett_bencode_dict);
|
|
}
|
|
|
|
used = 1;
|
|
length--;
|
|
|
|
while (length>=1) {
|
|
op = tvb_get_guint8(tvb, offset+used);
|
|
|
|
if (op=='e') {
|
|
return used+1;
|
|
}
|
|
|
|
op1len = dissect_bencoding_str(tvb, pinfo, offset+used, length, NULL, NULL, 0);
|
|
if (op1len<0) {
|
|
if (dtree) {
|
|
proto_tree_add_text(dtree, tvb, offset+used, -1, "Decode Aborted: Invalid Dictionary Key");
|
|
}
|
|
return op1len;
|
|
}
|
|
|
|
op2len = -1;
|
|
if (length-op1len>2)
|
|
op2len = dissect_bencoding_rec(tvb, pinfo, offset+used+op1len, length-op1len, NULL, level+1, NULL, 0);
|
|
if (op2len<0) {
|
|
if (dtree) {
|
|
proto_tree_add_text(dtree, tvb, offset+used+op1len, -1, "Decode Aborted: Invalid Dictionary Value");
|
|
}
|
|
return op2len;
|
|
}
|
|
|
|
if (dtree) {
|
|
ti = proto_tree_add_item(dtree, hf_bencode_dict_entry, tvb, offset+used, op1len+op2len, ENC_NA);
|
|
itree = proto_item_add_subtree(ti, ett_bencode_dict_entry);
|
|
|
|
dissect_bencoding_str(tvb, pinfo, offset+used, length, itree, ti, 1);
|
|
dissect_bencoding_rec(tvb, pinfo, offset+used+op1len, length-op1len, itree, level+1, ti, 2);
|
|
}
|
|
|
|
used += op1len+op2len;
|
|
length -= op1len+op2len;
|
|
}
|
|
if (dtree) {
|
|
proto_tree_add_text(dtree, tvb, offset+used, -1, "Truncated Data");
|
|
}
|
|
return -1;
|
|
|
|
case 'l':
|
|
if (tree) {
|
|
ti = proto_tree_add_item(tree, hf_bencode_list, tvb, offset, oplen, ENC_NA);
|
|
itree = proto_item_add_subtree(ti, ett_bencode_list);
|
|
}
|
|
|
|
used = 1;
|
|
length--;
|
|
|
|
while (length>=1) {
|
|
op = tvb_get_guint8(tvb, offset+used);
|
|
|
|
if (op=='e') {
|
|
return used+1;
|
|
}
|
|
|
|
oplen = dissect_bencoding_rec(tvb, pinfo, offset+used, length, itree, level+1, ti, 0);
|
|
if (oplen<1) return oplen;
|
|
|
|
used += oplen;
|
|
length -= oplen;
|
|
}
|
|
if (itree) {
|
|
proto_tree_add_text(itree, tvb, offset+used, -1, "Truncated Data");
|
|
}
|
|
return -1;
|
|
|
|
case 'i':
|
|
return dissect_bencoding_int(tvb, pinfo, offset, length, tree, treei, treeadd);
|
|
|
|
default:
|
|
if (op>='1' && op<='9') {
|
|
return dissect_bencoding_str(tvb, pinfo, offset, length, tree, treei, treeadd);
|
|
}
|
|
|
|
proto_tree_add_text(tree, tvb, offset, -1, "Decode Aborted: Invalid Bencoding");
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
static void dissect_bencoding(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
|
|
{
|
|
dissect_bencoding_rec(tvb, pinfo, 0, tvb_length(tvb), tree, 0, NULL, 0);
|
|
}
|
|
|
|
void
|
|
proto_register_bencode(void)
|
|
{
|
|
static hf_register_info hf[] = {
|
|
{ &hf_bencode_str_length,
|
|
{ "String Length", "bencode.str.length", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL }
|
|
},
|
|
{ &hf_bencode_str,
|
|
{ "String", "bencode.str", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL }
|
|
},
|
|
{ &hf_bencode_int,
|
|
{ "Integer", "bencode.int", FT_INT32, BASE_DEC, NULL, 0x0, NULL, HFILL }
|
|
},
|
|
{ &hf_bencode_dict,
|
|
{ "Dictionary", "bencode.dict", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }
|
|
},
|
|
{ &hf_bencode_dict_entry,
|
|
{ "Entry", "bencode.dict.entry", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }
|
|
},
|
|
{ &hf_bencode_list,
|
|
{ "List", "bencode.list", FT_NONE, BASE_NONE, NULL, 0x0, NULL, HFILL }
|
|
},
|
|
};
|
|
|
|
static gint *ett[] = {
|
|
&ett_bencode_dict,
|
|
&ett_bencode_dict_entry,
|
|
&ett_bencode_list,
|
|
};
|
|
|
|
proto_bencode = proto_register_protocol("Bencode", "Bencode", "bencode");
|
|
register_dissector("bencode", dissect_bencoding, proto_bencode);
|
|
proto_register_field_array(proto_bencode, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
}
|