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/* show_exception.c
*
* Routines to put exception information into the protocol tree
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 2000 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#define WS_LOG_DOMAIN LOG_DOMAIN_EPAN
#include <glib.h>
#include <epan/packet.h>
#include <epan/exceptions.h>
#include <epan/expert.h>
#include <epan/prefs.h>
#include <epan/prefs-int.h>
#include <epan/show_exception.h>
#include <wsutil/ws_assert.h>
#include <wsutil/wslog.h>
static int proto_short;
static int proto_dissector_bug;
static int proto_malformed;
static int proto_unreassembled;
static expert_field ei_dissector_bug;
static expert_field ei_malformed_reassembly;
static expert_field ei_malformed;
static expert_field ei_unreassembled;
void
register_show_exception(void)
{
static ei_register_info ei_dissector_bug_set[] = {
{ &ei_dissector_bug, { "_ws.dissector_bug", PI_DISSECTOR_BUG, PI_ERROR, "Dissector bug", EXPFILL }},
};
static ei_register_info ei_malformed_set[] = {
{ &ei_malformed_reassembly, { "_ws.malformed.reassembly", PI_MALFORMED, PI_ERROR, "Reassembly error", EXPFILL }},
{ &ei_malformed, { "_ws.malformed.expert", PI_MALFORMED, PI_ERROR, "Malformed Packet (Exception occurred)", EXPFILL }},
};
static ei_register_info ei_unreassembled_set[] = {
{ &ei_unreassembled, { "_ws.unreassembled.expert", PI_REASSEMBLE, PI_NOTE, "Unreassembled fragment (change preferences to enable reassembly)", EXPFILL }},
};
expert_module_t* expert_dissector_bug;
expert_module_t* expert_malformed;
expert_module_t* expert_unreassembled;
proto_short = proto_register_protocol("Short Frame", "Short frame", "_ws.short");
proto_dissector_bug = proto_register_protocol("Dissector Bug",
"Dissector bug", "_ws.dissector_bug");
proto_malformed = proto_register_protocol("Malformed Packet",
"Malformed packet", "_ws.malformed");
proto_unreassembled = proto_register_protocol(
"Unreassembled Fragmented Packet",
"Unreassembled fragmented packet", "_ws.unreassembled");
expert_dissector_bug = expert_register_protocol(proto_dissector_bug);
expert_register_field_array(expert_dissector_bug, ei_dissector_bug_set, array_length(ei_dissector_bug_set));
expert_malformed = expert_register_protocol(proto_malformed);
expert_register_field_array(expert_malformed, ei_malformed_set, array_length(ei_malformed_set));
expert_unreassembled = expert_register_protocol(proto_unreassembled);
expert_register_field_array(expert_unreassembled, ei_unreassembled_set, array_length(ei_unreassembled_set));
/* "Short Frame", "Dissector Bug", "Malformed Packet", and
"Unreassembled Fragmented Packet" aren't really protocols,
they're error indications; disabling them makes no sense. */
proto_set_cant_toggle(proto_short);
proto_set_cant_toggle(proto_dissector_bug);
proto_set_cant_toggle(proto_malformed);
proto_set_cant_toggle(proto_unreassembled);
}
void
show_exception(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
unsigned long exception, const char *exception_message)
{
static const char dissector_error_nomsg[] =
"Dissector writer didn't bother saying what the error was";
proto_item *item;
if ((exception == ReportedBoundsError || exception == ContainedBoundsError) && pinfo->fragmented)
exception = FragmentBoundsError;
switch (exception) {
case ScsiBoundsError:
col_append_str(pinfo->cinfo, COL_INFO, "[SCSI transfer limited due to allocation_length too small]");
proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
"SCSI transfer limited due to allocation_length too small: %s truncated]", pinfo->current_proto);
/* Don't record ScsiBoundsError exceptions as expert events - they merely
* reflect a normal SCSI condition.
* (any case where it's caused by something else is a bug). */
break;
case BoundsError:
{
bool display_info = true;
module_t * frame_module = prefs_find_module("frame");
if (frame_module != NULL)
{
pref_t *display_pref = prefs_find_preference(frame_module, "disable_packet_size_limited_in_summary");
if (display_pref)
{
if (prefs_get_bool_value(display_pref, pref_current))
display_info = false;
}
}
if (display_info)
col_append_str(pinfo->cinfo, COL_INFO, "[Packet size limited during capture]");
proto_tree_add_protocol_format(tree, proto_short, tvb, 0, 0,
"[Packet size limited during capture: %s truncated]", pinfo->current_proto);
/* Don't record BoundsError exceptions as expert events - they merely
* reflect a capture done with a snapshot length too short to capture
* all of the packet
* (any case where it's caused by something else is a bug). */
}
break;
case FragmentBoundsError:
col_append_fstr(pinfo->cinfo, COL_INFO, "[BoundErrorUnreassembled Packet%s]", pinfo->noreassembly_reason);
item = proto_tree_add_protocol_format(tree, proto_unreassembled,
tvb, 0, 0, "[BoundError Unreassembled Packet%s: %s]",
pinfo->noreassembly_reason, pinfo->current_proto);
/* FragmentBoundsError merely reflect dissection done with
* reassembly turned off, so add a note to that effect
* (any case where it's caused by something else is a bug). */
expert_add_info(pinfo, item, &ei_unreassembled);
break;
case ContainedBoundsError:
col_append_fstr(pinfo->cinfo, COL_INFO, "[Malformed Packet: length of contained item exceeds length of containing item]");
item = proto_tree_add_protocol_format(tree, proto_malformed,
tvb, 0, 0, "[Malformed Packet: %s: length of contained item exceeds length of containing item]",
pinfo->current_proto);
expert_add_info(pinfo, item, &ei_malformed);
break;
case ReportedBoundsError:
show_reported_bounds_error(tvb, pinfo, tree);
break;
case DissectorError:
col_append_fstr(pinfo->cinfo, COL_INFO,
"[Dissector bug, protocol %s: %s]",
pinfo->current_proto,
exception_message == NULL ?
dissector_error_nomsg : exception_message);
item = proto_tree_add_protocol_format(tree, proto_dissector_bug, tvb, 0, 0,
"[Dissector bug, protocol %s: %s]",
pinfo->current_proto,
exception_message == NULL ?
dissector_error_nomsg : exception_message);
ws_log(WS_LOG_DOMAIN, LOG_LEVEL_WARNING,
"Dissector bug, protocol %s, in packet %u: %s",
pinfo->current_proto, pinfo->num,
exception_message == NULL ?
dissector_error_nomsg : exception_message);
expert_add_info_format(pinfo, item, &ei_dissector_bug, "%s",
exception_message == NULL ?
dissector_error_nomsg : exception_message);
break;
case ReassemblyError:
col_append_fstr(pinfo->cinfo, COL_INFO,
"[Reassembly error, protocol %s: %s]",
pinfo->current_proto,
exception_message == NULL ?
dissector_error_nomsg : exception_message);
item = proto_tree_add_protocol_format(tree, proto_malformed, tvb, 0, 0,
"[Reassembly error, protocol %s: %s]",
pinfo->current_proto,
exception_message == NULL ?
dissector_error_nomsg : exception_message);
expert_add_info_format(pinfo, item, &ei_malformed_reassembly, "%s",
exception_message == NULL ?
dissector_error_nomsg : exception_message);
break;
default:
/* XXX - we want to know, if an unknown exception passed until here, don't we? */
ws_assert_not_reached();
}
}
void
show_reported_bounds_error(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *item;
col_append_str(pinfo->cinfo, COL_INFO,
"[Malformed Packet]");
item = proto_tree_add_protocol_format(tree, proto_malformed,
tvb, 0, 0, "[Malformed Packet: %s]", pinfo->current_proto);
expert_add_info(pinfo, item, &ei_malformed);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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