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wireshark/epan/dissectors/packet-ippusb.c

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/* packet-ippusb.c
* Routines for IPPUSB packet disassembly
* https://robots.org.uk/IPPOverUSB
*
* Jamie Hare <jamienh@umich.edu>
*
* PROTONAME: Internet Printing Protocol Over USB
* PROTOSHORTNAME: IPPUSB
* PROTOABBREV: ippusb
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/strutil.h>
#include <epan/to_str.h>
#include <epan/conversation.h>
#include <epan/wmem_scopes.h>
#include <reassemble.h>
#include <packet-usb.h>
/*
* IPPUSB transfer_type values
*/
#define HTTP 0
/* As also defined in IPP dissector */
#define PRINT_JOB 0x0002
#define SEND_DOCUMENT 0x0006
#define TAG_END_OF_ATTRIBUTES 0x03
#define NEWLINE 0x0a
#define CHUNK_LENGTH_MIN 5
#define BITS_PER_BYTE 8
static const guint8 CHUNKED_END[] = { 0x30, 0x0d, 0x0a, 0x0d, 0x0a };
static const guint8 RETURN_NEWLINE[] = { 0x0d, 0x0a };
static tvbuff_t *return_newline_tvb = NULL;
void proto_register_ippusb(void);
void proto_reg_handoff_ippusb(void);
static gint is_http_header(guint first_linelen, const guchar *first_line);
static gint proto_ippusb = -1;
static gint ett_ippusb = -1;
static gint ett_ippusb_as = -1;
static gint ett_ippusb_attr = -1;
static gint ett_ippusb_member = -1;
static gint ett_ippusb_fragment= -1;
static gint ett_ippusb_fragments = -1;
/* For reassembly */
static gint32 ippusb_last_pdu = -1;
static gint hf_ippusb_fragments = -1;
static gint hf_ippusb_fragment = -1;
static gint hf_ippusb_fragment_overlap = -1;
static gint hf_ippusb_fragment_overlap_conflict = -1;
static gint hf_ippusb_fragment_multiple_tails = -1;
static gint hf_ippusb_fragment_too_long_fragment = -1;
static gint hf_ippusb_fragment_error = -1;
static gint hf_ippusb_fragment_count = -1;
static gint hf_ippusb_reassembled_in = -1;
static gint hf_ippusb_reassembled_length = -1;
static gint hf_ippusb_reassembled_data = -1;
/* Reassemble by default */
static gboolean global_ippusb_reassemble = TRUE;
static const fragment_items ippusb_frag_items = {
&ett_ippusb_fragment,
&ett_ippusb_fragments,
&hf_ippusb_fragments,
&hf_ippusb_fragment,
&hf_ippusb_fragment_overlap,
&hf_ippusb_fragment_overlap_conflict,
&hf_ippusb_fragment_multiple_tails,
&hf_ippusb_fragment_too_long_fragment,
&hf_ippusb_fragment_error,
&hf_ippusb_fragment_count,
&hf_ippusb_reassembled_in,
&hf_ippusb_reassembled_length,
&hf_ippusb_reassembled_data,
"IPPUSB fragments"
};
struct ippusb_multisegment_pdu {
guint nxtpdu;
guint32 first_frame;
guint32 running_size;
gboolean finished;
gboolean reassembled;
gboolean is_ipp;
guint32 document;
#define MSP_HAS_DOCUMENT 0x00000001
#define MSP_DOCUMENT_TRUNCATED 0x00000002
guint32 flags;
#define MSP_FLAGS_REASSEMBLE_ENTIRE_SEGMENT 0x00000001
#define MSP_FLAGS_GOT_ALL_SEGMENTS 0x00000002
#define MSP_FLAGS_MISSING_FIRST_SEGMENT 0x00000004
};
static struct ippusb_multisegment_pdu *
pdu_store(packet_info *pinfo, wmem_tree_t *multisegment_pdus, guint32 first_frame, gboolean is_ipp, guint document)
{
struct ippusb_multisegment_pdu *msp;
msp = wmem_new(wmem_file_scope(), struct ippusb_multisegment_pdu);
msp->first_frame = first_frame;
msp->finished = FALSE;
msp->reassembled = FALSE;
msp->is_ipp = is_ipp;
msp->document = document;
msp->flags = 0;
wmem_tree_insert32(multisegment_pdus, pinfo->num, (void *)msp);
return msp;
}
struct ippusb_analysis {
wmem_tree_t *multisegment_pdus;
};
static struct ippusb_analysis *
init_ippusb_conversation_data(void)
{
struct ippusb_analysis *ippusbd;
ippusbd = wmem_new0(wmem_file_scope(), struct ippusb_analysis);
ippusbd->multisegment_pdus = wmem_tree_new(wmem_file_scope());
return ippusbd;
}
static struct ippusb_analysis *
get_ippusb_conversation_data(conversation_t *conv, packet_info *pinfo)
{
struct ippusb_analysis *ippusbd;
if(conv == NULL ) {
conv = find_or_create_conversation(pinfo);
}
ippusbd = (struct ippusb_analysis *)conversation_get_proto_data(conv, proto_ippusb);
if (!ippusbd) {
ippusbd = init_ippusb_conversation_data();
conversation_add_proto_data(conv, proto_ippusb, ippusbd);
}
return ippusbd;
}
static gpointer ippusb_temporary_key(const packet_info *pinfo _U_, const guint32 id _U_, const void *data)
{
return (gpointer)data;
}
static gpointer ippusb_persistent_key(const packet_info *pinfo _U_, const guint32 id _U_, const void *data)
{
return (gpointer)data;
}
static void ippusb_free_temporary_key(gpointer ptr _U_) { }
static void ippusb_free_persistent_key(gpointer ptr _U_) { }
static reassembly_table_functions ippusb_reassembly_table_functions =
{
g_direct_hash,
g_direct_equal,
ippusb_temporary_key,
ippusb_persistent_key,
ippusb_free_temporary_key,
ippusb_free_persistent_key
};
static dissector_table_t ippusb_dissector_table;
static reassembly_table ippusb_reassembly_table;
/* Main dissector function */
static int
dissect_ippusb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
gint offset = 0;
gint ret = 0;
guint first_linelen;
const guchar *first_line;
gint next_offset;
guint8 last;
guint8 status_code;
const guchar *last_chunk = NULL;
struct ippusb_analysis *ippusbd = NULL;
conversation_t *conv = NULL;
struct ippusb_multisegment_pdu *new_msp = NULL;
struct ippusb_multisegment_pdu *current_msp = NULL;
struct ippusb_multisegment_pdu *previous_msp = NULL;
gint reported_length = tvb_reported_length(tvb);
gint captured_length = tvb_captured_length(tvb);
if((conv = find_conversation_pinfo(pinfo, 0)) != NULL) {
/* Update how far the conversation reaches */
if (pinfo->num > conv->last_frame) {
conv->last_frame = pinfo->num;
}
}
else {
conv = conversation_new(pinfo->num, &pinfo->src, &pinfo->dst, CONVERSATION_TCP,
pinfo->srcport, pinfo->destport, 0);
}
ippusbd = get_ippusb_conversation_data(conv, pinfo);
first_linelen = tvb_find_line_end(tvb, offset, tvb_ensure_captured_length_remaining(tvb, offset), &next_offset, TRUE);
first_line = tvb_get_ptr(tvb, offset, first_linelen);
/* Get last byte of segment */
last = tvb_get_guint8(tvb, captured_length - 1);
status_code = tvb_get_bits8(tvb, 3 * BITS_PER_BYTE, BITS_PER_BYTE);
/* If segment has length of last chunk from chunk transfer */
if(captured_length == CHUNK_LENGTH_MIN){
last_chunk = tvb_get_ptr(tvb, offset, captured_length);
}
if (is_http_header(first_linelen, first_line) && last == TAG_END_OF_ATTRIBUTES && status_code != PRINT_JOB && status_code != SEND_DOCUMENT) {
/* An indiviual ippusb packet with http header */
proto_tree_add_item(tree, proto_ippusb, tvb, offset, -1, 0);
if (ippusb_last_pdu >= 0 && !pinfo->fd->visited) {
ippusb_last_pdu = -1;
}
ret = dissector_try_uint_new(ippusb_dissector_table, HTTP, tvb, pinfo, tree, TRUE, data);
}
else if (global_ippusb_reassemble) {
/* If reassembly is wanted */
if (!pinfo->fd->visited) {
/* First time this segment is ever seen */
gboolean save_fragmented = pinfo->fragmented;
pinfo->fragmented = TRUE;
proto_tree_add_item(tree, proto_ippusb, tvb, offset, -1, 0);
if (is_http_header(first_linelen, first_line)) {
/* The start of a new packet that will need to be reassembled */
new_msp = pdu_store(pinfo, ippusbd->multisegment_pdus, pinfo->num, TRUE, 0);
new_msp->running_size = captured_length;
fragment_add_check(&ippusb_reassembly_table, tvb, offset, pinfo, new_msp->first_frame,
GUINT_TO_POINTER(new_msp->first_frame), 0, captured_length, TRUE);
ippusb_last_pdu = pinfo->num;
}
else {
previous_msp = (struct ippusb_multisegment_pdu *)wmem_tree_lookup32_le(ippusbd->multisegment_pdus, ippusb_last_pdu);
if (previous_msp) {
previous_msp->nxtpdu = pinfo->num;
new_msp = pdu_store(pinfo, ippusbd->multisegment_pdus, previous_msp->first_frame, previous_msp->is_ipp, previous_msp->document);
new_msp->running_size = previous_msp->running_size + captured_length;
/* This packet has an HTTP header but is not an ipp packet */
if ((first_linelen >= strlen("Content-Type: ") && strncmp(first_line, "Content-Type: ", strlen("Content-Type: ")) == 0) &&
(first_linelen < strlen("Content-Type: application/ipp") || strncmp(first_line, "Content-Type: application/ipp", strlen("Content-Type: application/ipp")) != 0)) {
new_msp->is_ipp = FALSE;
}
/* This packet will have an attached document */
if (status_code == PRINT_JOB || status_code == SEND_DOCUMENT) {
new_msp->document |= MSP_HAS_DOCUMENT;
}
if(!(last_chunk && strncmp(last_chunk, CHUNKED_END, CHUNK_LENGTH_MIN) == 0)){
/* If this segment is not the last chunk in a chunked transfer */
if (captured_length < reported_length && (new_msp->document & MSP_HAS_DOCUMENT)) {
/* The attached document segment is smaller than it says it should be and cannot be reaseembled properly */
tvbuff_t *new_tvb = tvb_new_subset_length(tvb, 0, captured_length);
fragment_add_check(&ippusb_reassembly_table, new_tvb, offset, pinfo, new_msp->first_frame,
GUINT_TO_POINTER(new_msp->first_frame), previous_msp->running_size, captured_length, TRUE);
new_msp->document |= MSP_DOCUMENT_TRUNCATED;
}
else {
fragment_add_check(&ippusb_reassembly_table, tvb, offset, pinfo, new_msp->first_frame,
GUINT_TO_POINTER(new_msp->first_frame), previous_msp->running_size, captured_length, TRUE);
}
if (last != NEWLINE) {
fragment_add_check(&ippusb_reassembly_table, return_newline_tvb, offset, pinfo, new_msp->first_frame,
GUINT_TO_POINTER(new_msp->first_frame), new_msp->running_size, sizeof(RETURN_NEWLINE), TRUE);
new_msp->running_size += sizeof(RETURN_NEWLINE);
}
ippusb_last_pdu = pinfo->num;
}
else {
/* This segment contains the end of ipp chunked transfer information */
new_msp->finished = TRUE;
ippusb_last_pdu = -1;
fragment_head *head = fragment_add_check(&ippusb_reassembly_table, tvb, offset, pinfo, new_msp->first_frame,
GUINT_TO_POINTER(new_msp->first_frame), previous_msp->running_size, captured_length, FALSE);
tvbuff_t *processed_tvb = process_reassembled_data(tvb, offset, pinfo, "Reassembled IPPUSB", head, &ippusb_frag_items, NULL, tree);
new_msp->reassembled = TRUE;
pinfo->can_desegment = 0;
if(processed_tvb){
ret = dissector_try_uint_new(ippusb_dissector_table, HTTP, processed_tvb, pinfo, tree, TRUE, data);
col_append_fstr(pinfo->cinfo, COL_INFO, " Reassembled Data");
}
}
}
pinfo->fragmented = save_fragmented;
}
}
else {
/* Not the first time this segment is seen */
gboolean save_fragmented = pinfo->fragmented;
pinfo->fragmented = TRUE;
current_msp = (struct ippusb_multisegment_pdu *)wmem_tree_lookup32_le(ippusbd->multisegment_pdus, pinfo->num);
/* This is not an ipp packet */
if(current_msp && !(current_msp->is_ipp)){
return captured_length;
}
if (current_msp && !current_msp->finished && current_msp->nxtpdu == 0) {
/* This is a packet that was not completed and assembly will be attempted */
proto_tree_add_item(tree, proto_ippusb, tvb, offset, -1, 0);
fragment_head *head;
if (!current_msp->reassembled) {
/* The first time this segment is passed over after the initial round
* it will be added to the pdu and reassembled */
pinfo->fd->visited = FALSE;
if (captured_length < reported_length && (current_msp->document & MSP_HAS_DOCUMENT)) {
/* The attached document segment is smaller than it says it should be and cannot be reaseembled properly */
tvbuff_t *new_tvb = tvb_new_subset_length(tvb, 0, captured_length);
head = fragment_add_check(&ippusb_reassembly_table, new_tvb, offset, pinfo, current_msp->first_frame,
GUINT_TO_POINTER(current_msp->first_frame), current_msp->running_size - captured_length, captured_length, FALSE);
current_msp->document |= MSP_DOCUMENT_TRUNCATED;
}
else {
head = fragment_add_check(&ippusb_reassembly_table, tvb, 0, pinfo, current_msp->first_frame,
GUINT_TO_POINTER(current_msp->first_frame), current_msp->running_size - captured_length, captured_length, FALSE);
}
pinfo->fd->visited = TRUE;
current_msp->reassembled = TRUE;
}
else {
/* Packet has already been reassembled */
head = fragment_get_reassembled_id(&ippusb_reassembly_table, pinfo, current_msp->first_frame);
}
tvbuff_t *processed_tvb = process_reassembled_data(tvb, offset, pinfo, " Reassembled IPPUSB", head, &ippusb_frag_items, NULL, tree);
if (processed_tvb) {
pinfo->can_desegment = 0;
ret = dissector_try_uint_new(ippusb_dissector_table, HTTP, processed_tvb, pinfo, tree, TRUE, data);
if (current_msp->document & MSP_DOCUMENT_TRUNCATED) {
col_append_fstr(pinfo->cinfo, COL_INFO, " Document Truncated");
}
}
}
else if (current_msp &&last_chunk && strncmp(last_chunk, CHUNKED_END, CHUNK_LENGTH_MIN) == 0) {
/* This is the last segment of the chunked transfer and reassembled packet */
proto_tree_add_item(tree, proto_ippusb, tvb, offset, -1, 0);
fragment_head *head = fragment_get_reassembled_id(&ippusb_reassembly_table, pinfo, current_msp->first_frame);
tvbuff_t *processed_tvb = process_reassembled_data(tvb, offset, pinfo, " Reassembled IPPUSB", head, &ippusb_frag_items, NULL, tree);
if (processed_tvb) {
pinfo->can_desegment = 0;
ret = dissector_try_uint_new(ippusb_dissector_table, HTTP, processed_tvb, pinfo, tree, TRUE, data);
col_append_fstr(pinfo->cinfo, COL_INFO, " Reassembled Data");
/* If the document was truncated mark it as such in the UX */
if (current_msp->document & MSP_DOCUMENT_TRUNCATED) {
col_append_fstr(pinfo->cinfo, COL_INFO, " Document Truncated");
}
}
}
pinfo->fragmented = save_fragmented;
}
}
if (ret) {
return tvb_captured_length(tvb);
}
else {
return 0;
}
}
static gint
is_http_header(guint first_linelen, const guchar *first_line) {
if ((first_linelen >= strlen("HTTP/") && strncmp(first_line, "HTTP/", strlen("HTTP/")) == 0) ||
(first_linelen >= strlen("POST /ipp") && strncmp(first_line, "POST /ipp", strlen("POST /ipp")) == 0) ||
(first_linelen >= strlen("POST / HTTP") && strncmp(first_line, "POST / HTTP", strlen("POST / HTTP")) == 0)) {
return TRUE;
}
else {
return FALSE;
}
}
static void
ippusb_shutdown(void) {
tvb_free(return_newline_tvb);
}
void
proto_register_ippusb(void)
{
static hf_register_info hf[] = {
/* Reassembly */
{ &hf_ippusb_fragment,
{ "Fragment", "ippusb.fragment", FT_FRAMENUM, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ &hf_ippusb_fragments,
{ "Fragments", "ippusb.fragments", FT_BYTES, BASE_NONE,
NULL, 0x0, NULL, HFILL }},
{ &hf_ippusb_fragment_overlap,
{ "Fragment overlap", "ippusb.fragment.overlap", FT_BOOLEAN, BASE_NONE,
NULL, 0x0, "Fragment overlaps with other fragments", HFILL }},
{ &hf_ippusb_fragment_overlap_conflict,
{ "Conflicting data in fragment overlap", "ippusb.fragment.overlap.conflict",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"Overlapping fragments contained conflicting data", HFILL }},
{ &hf_ippusb_fragment_multiple_tails,
{ "Multiple tail fragments found", "ippusb.fragment.multipletails",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"Several tails were found when defragmenting the packet", HFILL }},
{ &hf_ippusb_fragment_too_long_fragment,
{ "Fragment too long", "ippusb.fragment.toolongfragment",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"Fragment contained data past end of packet", HFILL }},
{ &hf_ippusb_fragment_error,
{ "Defragmentation error", "ippusb.fragment.error", FT_FRAMENUM, BASE_NONE,
NULL, 0x0, "Defragmentation error due to illegal fragments", HFILL }},
{ &hf_ippusb_fragment_count,
{ "Fragment count", "ippusb.fragment.count", FT_UINT32, BASE_DEC,
NULL, 0x0, NULL, HFILL }},
{ &hf_ippusb_reassembled_in,
{ "Reassembled payload in frame", "ippusb.reassembled_in", FT_FRAMENUM, BASE_NONE,
NULL, 0x0, "This payload packet is reassembled in this frame", HFILL }},
{ &hf_ippusb_reassembled_length,
{ "Reassembled payload length", "ippusb.reassembled.length", FT_UINT32, BASE_DEC,
NULL, 0x0, "The total length of the reassembled payload", HFILL }},
{ &hf_ippusb_reassembled_data,
{ "Reassembled data", "ippusb.reassembled.data", FT_BYTES, BASE_NONE,
NULL, 0x0, "The reassembled payload", HFILL }},
};
static gint *ett[] = {
&ett_ippusb,
&ett_ippusb_as,
&ett_ippusb_attr,
&ett_ippusb_member,
&ett_ippusb_fragments,
&ett_ippusb_fragment
};
proto_ippusb = proto_register_protocol("Internet Printing Protocol Over USB", "IPPUSB", "ippusb");
ippusb_dissector_table = register_dissector_table("ippusb", "IPP Over USB", proto_ippusb, FT_UINT8, BASE_DEC);
proto_register_field_array(proto_ippusb, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Register reassembly table. */
reassembly_table_register(&ippusb_reassembly_table, &ippusb_reassembly_table_functions);
/* Preferences */
module_t *ippusb_module = prefs_register_protocol(proto_ippusb, NULL);
/* Reassembly, made an option due to memory costs */
prefs_register_bool_preference(ippusb_module, "attempt_reassembly", "Reassemble payload", "", &global_ippusb_reassemble);
return_newline_tvb = tvb_new_real_data(RETURN_NEWLINE, sizeof(RETURN_NEWLINE), sizeof(RETURN_NEWLINE));
register_shutdown_routine(ippusb_shutdown);
}
void
proto_reg_handoff_ippusb(void)
{
dissector_handle_t ippusb_handle;
ippusb_handle = create_dissector_handle(dissect_ippusb, proto_ippusb);
dissector_add_uint("usb.bulk", IF_CLASS_PRINTER, ippusb_handle);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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