/* packet-syslog.c * Routines for syslog message dissection * * Copyright 2000, Gerald Combs * * Support for passing SS7 MSUs (from the Cisco ITP Packet Logging * facility) to the MTP3 dissector by Abhik Sarkar * with some rework by Jeff Morriss * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #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: */