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wireshark/epan/dissectors/packet-syslog.c

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/* packet-syslog.c
* Routines for syslog message dissection
*
* Copyright 2000, Gerald Combs <gerald[AT]wireshark.org>
*
* Support for passing SS7 MSUs (from the Cisco ITP Packet Logging
* facility) to the MTP3 dissector by Abhik Sarkar <sarkar.abhik[AT]gmail.com>
* with some rework by Jeff Morriss <jeff.morriss.ws [AT] gmail.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald[AT]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 "packet-syslog.h"
#include "packet-acdr.h"
#define UDP_PORT_SYSLOG 514
#define PRIORITY_MASK 0x0007 /* 0000 0111 */
#define FACILITY_MASK 0x03f8 /* 1111 1000 */
void proto_reg_handoff_syslog(void);
void proto_register_syslog(void);
/* The maximum number if priority digits to read in. */
#define MAX_DIGITS 3
static const value_string short_level_vals[] = {
{ LEVEL_EMERG, "EMERG" },
{ LEVEL_ALERT, "ALERT" },
{ LEVEL_CRIT, "CRIT" },
{ LEVEL_ERR, "ERR" },
{ LEVEL_WARNING, "WARNING" },
{ LEVEL_NOTICE, "NOTICE" },
{ LEVEL_INFO, "INFO" },
{ LEVEL_DEBUG, "DEBUG" },
{ 0, NULL }
};
static const value_string short_facility_vals[] = {
{ FAC_KERN, "KERN" },
{ FAC_USER, "USER" },
{ FAC_MAIL, "MAIL" },
{ FAC_DAEMON, "DAEMON" },
{ FAC_AUTH, "AUTH" },
{ FAC_SYSLOG, "SYSLOG" },
{ FAC_LPR, "LPR" },
{ FAC_NEWS, "NEWS" },
{ FAC_UUCP, "UUCP" },
{ FAC_CRON, "CRON" }, /* The BSDs, Linux, and others */
{ FAC_AUTHPRIV, "AUTHPRIV" },
{ FAC_FTP, "FTP" },
{ FAC_NTP, "NTP" },
{ FAC_LOGAUDIT, "LOGAUDIT" },
{ FAC_LOGALERT, "LOGALERT" },
{ FAC_CRON_SOL, "CRON" }, /* Solaris */
{ FAC_LOCAL0, "LOCAL0" },
{ FAC_LOCAL1, "LOCAL1" },
{ FAC_LOCAL2, "LOCAL2" },
{ FAC_LOCAL3, "LOCAL3" },
{ FAC_LOCAL4, "LOCAL4" },
{ FAC_LOCAL5, "LOCAL5" },
{ FAC_LOCAL6, "LOCAL6" },
{ FAC_LOCAL7, "LOCAL7" },
{ 0, NULL }
};
static gint proto_syslog = -1;
static gint hf_syslog_level = -1;
static gint hf_syslog_facility = -1;
static gint hf_syslog_msg = -1;
static gint hf_syslog_msu_present = -1;
static gint hf_syslog_version = -1;
static gint hf_syslog_timestamp = -1;
static gint hf_syslog_timestamp_old = -1;
static gint hf_syslog_hostname = -1;
static gint hf_syslog_appname = -1;
static gint hf_syslog_procid = -1;
static gint hf_syslog_msgid = -1;
static gint hf_syslog_msgid_utf8 = -1;
static gint hf_syslog_msgid_bom = -1;
static gint ett_syslog = -1;
static gint ett_syslog_msg = -1;
static dissector_handle_t syslog_handle;
static dissector_handle_t mtp_handle;
/* The Cisco ITP's packet logging facility allows selected (SS7) MSUs to be
* to be encapsulated in syslog UDP datagrams and sent to a monitoring tool.
* However, no actual tool to monitor/decode the MSUs is provided. The aim
* of this routine is to extract the hex dump of the MSU from the syslog
* packet so that it can be passed on to the mtp3 dissector for decoding.
*/
static tvbuff_t *
mtp3_msu_present(tvbuff_t *tvb, packet_info *pinfo, gint fac, gint level, const char *msg_str, gint chars_truncated)
{
size_t nbytes;
size_t len;
gchar **split_string, *msu_hex_dump;
tvbuff_t *mtp3_tvb = NULL;
guint8 *byte_array;
/* In the sample capture I have, all MSUs are LOCAL0.DEBUG.
* Try to optimize this routine for most syslog users by short-cutting
* out here.
*/
if (!(fac == FAC_LOCAL0 && level == LEVEL_DEBUG))
return NULL;
if (strstr(msg_str, "msu=") == NULL)
return NULL;
split_string = g_strsplit(msg_str, "msu=", 2);
msu_hex_dump = split_string[1];
if (msu_hex_dump && (len = strlen(msu_hex_dump))) {
/* convert_string_to_hex() will return NULL if it gets an incomplete
* byte. If we have an odd string length then chop off the remaining
* nibble so we can get at least a partial MSU (chances are the
* subdissector will except out, of course).
*/
if (len % 2)
msu_hex_dump[len - 1] = '\0';
byte_array = convert_string_to_hex(msu_hex_dump, &nbytes);
if (byte_array) {
mtp3_tvb = tvb_new_child_real_data(tvb, byte_array, (guint)nbytes,
(guint)nbytes + chars_truncated / 2);
tvb_set_free_cb(mtp3_tvb, g_free);
/* ...and add the encapsulated MSU as a new data source so that it gets
* its own tab in the packet bytes pane.
*/
add_new_data_source(pinfo, mtp3_tvb, "Encapsulated MSU");
}
}
g_strfreev(split_string);
return(mtp3_tvb);
}
static gboolean dissect_syslog_info(proto_tree* tree, tvbuff_t* tvb, guint* offset, gint hfindex)
{
gint end_offset = tvb_find_guint8(tvb, *offset, -1, ' ');
if (end_offset == -1)
return FALSE;
proto_tree_add_item(tree, hfindex, tvb, *offset, end_offset - *offset, ENC_NA);
*offset = end_offset + 1;
return TRUE;
}
/* Dissect message as defined in RFC5424 */
static void
dissect_syslog_message(proto_tree* tree, tvbuff_t* tvb, guint offset)
{
gint end_offset;
if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_version))
return;
end_offset = tvb_find_guint8(tvb, offset, -1, ' ');
if (end_offset == -1)
return;
if ((guint)end_offset != offset) {
/* do not call proto_tree_add_time_item with a length of 0 */
proto_tree_add_time_item(tree, hf_syslog_timestamp, tvb, offset, end_offset - offset, ENC_ISO_8601_DATE_TIME,
NULL, NULL, NULL);
}
offset = end_offset + 1;
if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_hostname))
return;
if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_appname))
return;
if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_procid))
return;
if (tvb_get_guint24(tvb, offset, ENC_BIG_ENDIAN) == 0xefbbbf) {
proto_tree_add_item(tree, hf_syslog_msgid_bom, tvb, offset, 3, ENC_BIG_ENDIAN);
offset += 3;
proto_tree_add_item(tree, hf_syslog_msgid_utf8, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_UTF_8);
} else {
proto_tree_add_item(tree, hf_syslog_msgid, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII);
}
}
/* Dissect message as defined in RFC3164 */
static void
dissect_rfc3164_syslog_message(proto_tree* tree, tvbuff_t* tvb, guint offset)
{
guint tvb_offset = 0;
/* Simple check if the first 16 bytes look like TIMESTAMP "Mmm dd hh:mm:ss"
* by checking for spaces and colons. Otherwise return without processing
* the message. */
if (tvb_get_guint8(tvb, offset + 3) == ' ' && tvb_get_guint8(tvb, offset + 6) == ' ' &&
tvb_get_guint8(tvb, offset + 9) == ':' && tvb_get_guint8(tvb, offset + 12) == ':' &&
tvb_get_guint8(tvb, offset + 15) == ' ') {
proto_tree_add_item(tree, hf_syslog_timestamp_old, tvb, offset, 15, ENC_ASCII);
offset += 16;
} else {
return;
}
if (!dissect_syslog_info(tree, tvb, &offset, hf_syslog_hostname))
return;
for (tvb_offset=offset; tvb_offset < offset+32; tvb_offset++){
guint8 octet;
octet = tvb_get_guint8(tvb, tvb_offset);
if (!g_ascii_isalnum(octet)){
proto_tree_add_item(tree, hf_syslog_procid, tvb, offset, tvb_offset - offset, ENC_ASCII);
offset = tvb_offset;
break;
}
}
proto_tree_add_item(tree, hf_syslog_msgid, tvb, offset, tvb_reported_length_remaining(tvb, offset), ENC_ASCII);
}
/* The message format is defined in RFC 3164 */
static int
dissect_syslog(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
gint pri = -1, lev = -1, fac = -1;
gint msg_off = 0, msg_len, reported_msg_len;
proto_item *ti;
proto_tree *syslog_tree;
proto_tree *syslog_message_tree;
const char *msg_str;
tvbuff_t *mtp3_tvb;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "Syslog");
col_clear(pinfo->cinfo, COL_INFO);
if (tvb_get_guint8(tvb, msg_off) == '<') {
/* A facility and level follow. */
msg_off++;
pri = 0;
while (tvb_bytes_exist(tvb, msg_off, 1) &&
g_ascii_isdigit(tvb_get_guint8(tvb, msg_off)) && msg_off <= MAX_DIGITS) {
pri = pri * 10 + (tvb_get_guint8(tvb, msg_off) - '0');
msg_off++;
}
if (tvb_get_guint8(tvb, msg_off) == '>')
msg_off++;
fac = (pri & FACILITY_MASK) >> 3;
lev = pri & PRIORITY_MASK;
}
msg_len = tvb_ensure_captured_length_remaining(tvb, msg_off);
msg_str = tvb_format_text(pinfo->pool, tvb, msg_off, msg_len);
reported_msg_len = tvb_reported_length_remaining(tvb, msg_off);
mtp3_tvb = mtp3_msu_present(tvb, pinfo, fac, lev, msg_str,
(reported_msg_len - msg_len));
if (mtp3_tvb == NULL) {
if (pri >= 0) {
col_add_fstr(pinfo->cinfo, COL_INFO, "%s.%s: %s",
val_to_str_const(fac, short_facility_vals, "UNKNOWN"),
val_to_str_const(lev, short_level_vals, "UNKNOWN"), msg_str);
} else {
col_add_str(pinfo->cinfo, COL_INFO, msg_str);
}
}
if (tree) {
if (pri >= 0) {
ti = proto_tree_add_protocol_format(tree, proto_syslog, tvb, 0, -1,
"Syslog message: %s.%s: %s",
val_to_str_const(fac, short_facility_vals, "UNKNOWN"),
val_to_str_const(lev, short_level_vals, "UNKNOWN"), msg_str);
} else {
ti = proto_tree_add_protocol_format(tree, proto_syslog, tvb, 0, -1,
"Syslog message: (unknown): %s", msg_str);
}
syslog_tree = proto_item_add_subtree(ti, ett_syslog);
if (pri >= 0) {
proto_tree_add_uint(syslog_tree, hf_syslog_facility, tvb, 0,
msg_off, pri);
proto_tree_add_uint(syslog_tree, hf_syslog_level, tvb, 0,
msg_off, pri);
}
ti = proto_tree_add_item(syslog_tree, hf_syslog_msg, tvb, msg_off,
msg_len, ENC_UTF_8);
syslog_message_tree = proto_item_add_subtree(ti, ett_syslog_msg);
/* RFC5424 defines a version field which is currently defined as '1'
* followed by a space (0x3120). Otherwise the message is probable
* a RFC3164 message.
*/
if (msg_len > 2 && tvb_get_ntohs(tvb, msg_off) == 0x3120) {
dissect_syslog_message(syslog_message_tree, tvb, msg_off);
} else if ( msg_len > 15) {
dissect_rfc3164_syslog_message(syslog_message_tree, tvb, msg_off);
}
if (mtp3_tvb) {
proto_item *mtp3_item;
mtp3_item = proto_tree_add_boolean(syslog_tree, hf_syslog_msu_present,
tvb, msg_off, msg_len, TRUE);
proto_item_set_generated(mtp3_item);
}
}
/* Call MTP dissector if encapsulated MSU was found... */
if (mtp3_tvb) {
call_dissector(mtp_handle, mtp3_tvb, pinfo, tree);
}
return tvb_captured_length(tvb);
}
/* Register the protocol with Wireshark */
void proto_register_syslog(void)
{
/* Setup list of header fields */
static hf_register_info hf[] = {
{ &hf_syslog_facility,
{ "Facility", "syslog.facility",
FT_UINT8, BASE_DEC, VALS(syslog_facility_vals), FACILITY_MASK,
"Message facility", HFILL }
},
{ &hf_syslog_level,
{ "Level", "syslog.level",
FT_UINT8, BASE_DEC, VALS(syslog_level_vals), PRIORITY_MASK,
"Message level", HFILL }
},
{ &hf_syslog_msg,
{ "Message", "syslog.msg",
FT_STRING, BASE_NONE, NULL, 0x0,
"Message Text", HFILL }
},
{ &hf_syslog_msu_present,
{ "SS7 MSU present", "syslog.msu_present",
FT_BOOLEAN, BASE_NONE, NULL, 0x0,
"True if an SS7 MSU was detected in the syslog message",
HFILL }
},
{ &hf_syslog_version,
{ "Syslog version", "syslog.version",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_timestamp,
{ "Syslog timestamp", "syslog.timestamp",
FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_timestamp_old,
{ "Syslog timestamp (RFC3164)", "syslog.timestamp_rfc3164",
FT_STRING, ENC_ASCII, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_hostname,
{ "Syslog hostname", "syslog.hostname",
FT_STRING, ENC_ASCII, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_appname,
{ "Syslog app name", "syslog.appname",
FT_STRING, ENC_ASCII, NULL, 0x0,
"The name of the app that generated this message",
HFILL }
},
{ &hf_syslog_procid,
{ "Syslog process id", "syslog.procid",
FT_STRING, ENC_ASCII, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_msgid,
{ "Syslog message id", "syslog.msgid",
FT_STRING, ENC_ASCII, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_msgid_utf8,
{ "Syslog message id", "syslog.msgid",
FT_STRING, BASE_NONE, NULL, 0x0,
NULL,
HFILL }
},
{ &hf_syslog_msgid_bom,
{ "Syslog BOM", "syslog.msgid.bom",
FT_UINT24, BASE_HEX, NULL, 0x0,
NULL,
HFILL }
}
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_syslog,
&ett_syslog_msg
};
/* Register the protocol name and description */
proto_syslog = proto_register_protocol("Syslog message", "Syslog", "syslog");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_syslog, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
syslog_handle = register_dissector("syslog", dissect_syslog, proto_syslog);
}
void
proto_reg_handoff_syslog(void)
{
dissector_add_uint_with_preference("udp.port", UDP_PORT_SYSLOG, syslog_handle);
dissector_add_for_decode_as_with_preference("tcp.port", syslog_handle);
dissector_add_uint("acdr.media_type", ACDR_Info, syslog_handle);
/* Find the mtp3 dissector */
mtp_handle = find_dissector_add_dependency("mtp3", proto_syslog);
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local Variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
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