![Ronnie Sahlberg](/assets/img/avatar_default.png)
change two gmemchunks in smtp to se_alloc() and remove one now redundant init routine. svn path=/trunk/; revision=15308
577 lines
16 KiB
C
577 lines
16 KiB
C
/* packet-smtp.c
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* Routines for SMTP packet disassembly
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*
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* $Id$
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*
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* Copyright (c) 2000 by Richard Sharpe <rsharpe@ns.aus.com>
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1999 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <time.h>
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#include <glib.h>
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#include <string.h>
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#include <epan/packet.h>
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#include <epan/conversation.h>
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#include <epan/addr_resolv.h>
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#include <epan/prefs.h>
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#include <epan/strutil.h>
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#include <epan/emem.h>
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#define TCP_PORT_SMTP 25
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static int proto_smtp = -1;
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static int hf_smtp_req = -1;
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static int hf_smtp_rsp = -1;
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static int hf_smtp_req_command = -1;
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static int hf_smtp_req_parameter = -1;
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static int hf_smtp_rsp_code = -1;
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static int hf_smtp_rsp_parameter = -1;
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static int ett_smtp = -1;
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static int ett_smtp_cmdresp = -1;
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/* desegmentation of SMTP command and response lines */
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static gboolean smtp_desegment = TRUE;
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/*
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* A CMD is an SMTP command, MESSAGE is the message portion, and EOM is the
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* last part of a message
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*/
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#define SMTP_PDU_CMD 0
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#define SMTP_PDU_MESSAGE 1
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#define SMTP_PDU_EOM 2
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struct smtp_proto_data {
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guint16 pdu_type;
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};
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/*
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* State information stored with a conversation.
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*/
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struct smtp_request_val {
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gboolean reading_data; /* Reading message data, not commands */
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guint16 crlf_seen; /* Have we seen a CRLF on the end of a packet */
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};
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static void
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dissect_smtp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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struct smtp_proto_data *frame_data;
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proto_tree *smtp_tree;
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proto_tree *cmdresp_tree;
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proto_item *ti;
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int offset = 0;
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int request = 0;
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conversation_t *conversation;
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struct smtp_request_val *request_val;
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const guchar *line;
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guint32 code;
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int linelen;
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gint length_remaining;
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gboolean eom_seen = FALSE;
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gint next_offset;
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gboolean is_continuation_line;
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int cmdlen;
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/* As there is no guarantee that we will only see frames in the
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* the SMTP conversation once, and that we will see them in
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* order - in Ethereal, the user could randomly click on frames
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* in the conversation in any order in which they choose - we
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* have to store information with each frame indicating whether
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* it contains commands or data or an EOM indication.
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*
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* XXX - what about frames that contain *both*? TCP is a
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* byte-stream protocol, and there are no guarantees that
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* TCP segment boundaries will correspond to SMTP commands
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* or EOM indications.
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*
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* We only need that for the client->server stream; responses
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* are easy to manage.
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*
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* If we have per frame data, use that, else, we must be on the first
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* pass, so we figure it out on the first pass.
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*/
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/* Find out what conversation this packet is part of ... but only
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* if we have no information on this packet, so find the per-frame
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* info first.
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*/
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/* SMTP messages have a simple format ... */
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request = pinfo -> destport == pinfo -> match_port;
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/*
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* Get the first line from the buffer.
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*
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* Note that "tvb_find_line_end()" will, if it doesn't return
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* -1, return a value that is not longer than what's in the buffer,
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* and "tvb_find_line_end()" will always return a value that is not
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* longer than what's in the buffer, so the "tvb_get_ptr()" call
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* won't throw an exception.
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*/
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linelen = tvb_find_line_end(tvb, offset, -1, &next_offset,
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smtp_desegment && pinfo->can_desegment);
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if (linelen == -1) {
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/*
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* We didn't find a line ending, and we're doing desegmentation;
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* tell the TCP dissector where the data for this message starts
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* in the data it handed us, and tell it we need one more byte
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* (we may need more, but we'll try again if what we get next
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* isn't enough), and return.
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*/
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pinfo->desegment_offset = offset;
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pinfo->desegment_len = 1;
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return;
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}
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line = tvb_get_ptr(tvb, offset, linelen);
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frame_data = p_get_proto_data(pinfo->fd, proto_smtp);
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if (!frame_data) {
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conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype,
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pinfo->srcport, pinfo->destport, 0);
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if (conversation == NULL) { /* No conversation, create one */
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conversation = conversation_new(pinfo->fd->num, &pinfo->src, &pinfo->dst, pinfo->ptype,
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pinfo->srcport, pinfo->destport, 0);
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}
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/*
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* Is there a request structure attached to this conversation?
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*/
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request_val = conversation_get_proto_data(conversation, proto_smtp);
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if (!request_val) {
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/*
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* No - create one and attach it.
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*/
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request_val = se_alloc(sizeof(struct smtp_request_val));
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request_val->reading_data = FALSE;
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request_val->crlf_seen = 0;
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conversation_add_proto_data(conversation, proto_smtp, request_val);
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}
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/*
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* Check whether or not this packet is an end of message packet
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* We should look for CRLF.CRLF and they may be split.
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* We have to keep in mind that we may see what we want on
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* two passes through here ...
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*/
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if (request_val->reading_data) {
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/*
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* The order of these is important ... We want to avoid
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* cases where there is a CRLF at the end of a packet and a
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* .CRLF at the begining of the same packet.
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*/
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if ((request_val->crlf_seen && tvb_strneql(tvb, offset, ".\r\n", 3) == 0) ||
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tvb_strneql(tvb, offset, "\r\n.\r\n", 5) == 0) {
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eom_seen = TRUE;
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}
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length_remaining = tvb_length_remaining(tvb, offset);
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if (length_remaining == tvb_reported_length_remaining(tvb, offset) &&
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tvb_strneql(tvb, offset + length_remaining - 2, "\r\n", 2) == 0) {
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request_val->crlf_seen = 1;
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}
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else {
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request_val->crlf_seen = 0;
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}
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}
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/*
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* OK, Check if we have seen a DATA request. We do it here for
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* simplicity, but we have to be careful below.
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*/
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if (request) {
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frame_data = se_alloc(sizeof(struct smtp_proto_data));
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if (request_val->reading_data) {
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/*
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* This is message data.
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*/
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if (eom_seen) { /* Seen the EOM */
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/*
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* EOM.
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* Everything that comes after it is commands.
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*
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* XXX - what if the EOM isn't at the beginning of
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* the TCP segment? It can occur anywhere....
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*/
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frame_data->pdu_type = SMTP_PDU_EOM;
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request_val->reading_data = FALSE;
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} else {
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/*
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* Message data with no EOM.
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*/
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frame_data->pdu_type = SMTP_PDU_MESSAGE;
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}
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} else {
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/*
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* This is commands - unless the capture started in the
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* middle of a session, and we're in the middle of data.
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* To quote RFC 821, "Command codes are four alphabetic
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* characters"; if we don't see four alphabetic characters
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* and, if there's anything else in the line, a space, we
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* assume it's not a command.
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* (We treat only A-Z and a-z as alphabetic.)
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*/
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#define ISALPHA(c) (((c) >= 'A' && (c) <= 'Z') || \
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((c) >= 'a' && (c) <= 'z'))
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if (linelen >= 4 && ISALPHA(line[0]) && ISALPHA(line[1]) &&
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ISALPHA(line[2]) && ISALPHA(line[3]) &&
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(linelen == 4 || line[4] == ' ')) {
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if (strncasecmp(line, "DATA", 4) == 0) {
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/*
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* DATA command.
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* This is a command, but everything that comes after it,
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* until an EOM, is data.
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*/
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frame_data->pdu_type = SMTP_PDU_CMD;
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request_val->reading_data = TRUE;
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} else {
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/*
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* Regular command.
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*/
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frame_data->pdu_type = SMTP_PDU_CMD;
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}
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} else {
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if ((linelen >= 7) && line[0] == 'X' && ( (strncasecmp(line, "X-EXPS ", 7) == 0) ||
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((linelen >=13) && (strncasecmp(line, "X-LINK2STATE ", 13) == 0)) ||
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((linelen >= 8) && (strncasecmp(line, "XEXCH50 ", 8) == 0)) ))
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frame_data->pdu_type = SMTP_PDU_CMD;
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else
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/*
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* Assume it's message data.
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*/
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frame_data->pdu_type = SMTP_PDU_MESSAGE;
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}
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}
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p_add_proto_data(pinfo->fd, proto_smtp, frame_data);
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}
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}
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/*
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* From here, we simply add items to the tree and info to the info
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* fields ...
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*/
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "SMTP");
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if (check_col(pinfo->cinfo, COL_INFO)) { /* Add the appropriate type here */
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/*
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* If it is a request, we have to look things up, otherwise, just
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* display the right things
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*/
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if (request) {
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/* We must have frame_data here ... */
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switch (frame_data->pdu_type) {
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case SMTP_PDU_MESSAGE:
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col_set_str(pinfo->cinfo, COL_INFO, "Message Body");
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break;
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case SMTP_PDU_EOM:
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col_add_fstr(pinfo->cinfo, COL_INFO, "EOM: %s",
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format_text(line, linelen));
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break;
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case SMTP_PDU_CMD:
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col_add_fstr(pinfo->cinfo, COL_INFO, "Command: %s",
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format_text(line, linelen));
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break;
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}
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}
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else {
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col_add_fstr(pinfo->cinfo, COL_INFO, "Response: %s",
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format_text(line, linelen));
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}
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}
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if (tree) { /* Build the tree info ... */
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ti = proto_tree_add_item(tree, proto_smtp, tvb, offset, -1, FALSE);
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smtp_tree = proto_item_add_subtree(ti, ett_smtp);
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if (request) {
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/*
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* Check out whether or not we can see a command in there ...
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* What we are looking for is not data_seen and the word DATA
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* and not eom_seen.
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*
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* We will see DATA and request_val->data_seen when we process the
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* tree view after we have seen a DATA packet when processing
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* the packet list pane.
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*
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* On the first pass, we will not have any info on the packets
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* On second and subsequent passes, we will.
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*/
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switch (frame_data->pdu_type) {
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case SMTP_PDU_MESSAGE:
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/*
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* Message body.
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* Put its lines into the protocol tree, a line at a time.
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*/
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while (tvb_offset_exists(tvb, offset)) {
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/*
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* Find the end of the line.
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*/
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tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
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/*
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* Put this line.
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*/
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proto_tree_add_text(smtp_tree, tvb, offset, next_offset - offset,
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"Message: %s",
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tvb_format_text(tvb, offset, next_offset - offset));
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/*
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* Step to the next line.
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*/
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offset = next_offset;
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}
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break;
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case SMTP_PDU_EOM:
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/*
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* End-of-message-body indicator.
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*
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* XXX - what about stuff after the first line?
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* Unlikely, as the client should wait for a response to the
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* DATA command this terminates before sending another
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* request, but we should probably handle it.
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*/
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proto_tree_add_text(smtp_tree, tvb, offset, linelen,
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"EOM: %s", format_text(line, linelen));
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break;
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case SMTP_PDU_CMD:
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/*
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* Command.
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*
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* XXX - what about stuff after the first line?
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* Unlikely, as the client should wait for a response to the
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* previous command before sending another request, but we
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* should probably handle it.
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*/
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if (linelen >= 4)
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cmdlen = 4;
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else
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cmdlen = linelen;
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proto_tree_add_boolean_hidden(smtp_tree, hf_smtp_req, tvb,
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0, 0, TRUE);
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/*
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* Put the command line into the protocol tree.
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*/
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ti = proto_tree_add_text(smtp_tree, tvb, offset, next_offset - offset,
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"Command: %s",
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tvb_format_text(tvb, offset, next_offset - offset));
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cmdresp_tree = proto_item_add_subtree(ti, ett_smtp_cmdresp);
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proto_tree_add_item(cmdresp_tree, hf_smtp_req_command, tvb,
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offset, cmdlen, FALSE);
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if (linelen > 5) {
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proto_tree_add_item(cmdresp_tree, hf_smtp_req_parameter, tvb,
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offset + 5, linelen - 5, FALSE);
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}
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}
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}
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else {
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/*
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* Process the response, a line at a time, until we hit a line
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* that doesn't have a continuation indication on it.
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*/
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proto_tree_add_boolean_hidden(smtp_tree, hf_smtp_rsp, tvb,
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0, 0, TRUE);
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while (tvb_offset_exists(tvb, offset)) {
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/*
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* Find the end of the line.
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*/
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linelen = tvb_find_line_end(tvb, offset, -1, &next_offset, FALSE);
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/*
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* Put it into the protocol tree.
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*/
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ti = proto_tree_add_text(smtp_tree, tvb, offset,
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next_offset - offset, "Response: %s",
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tvb_format_text(tvb, offset,
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next_offset - offset));
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cmdresp_tree = proto_item_add_subtree(ti, ett_smtp_cmdresp);
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/*
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* Is it a continuation line?
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*/
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is_continuation_line =
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(linelen >= 4 && tvb_get_guint8(tvb, offset + 3) == '-');
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/*
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* Put the response code and parameters into the protocol tree.
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*/
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line = tvb_get_ptr(tvb, offset, linelen);
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if (linelen >= 3 && isdigit(line[0]) && isdigit(line[1])
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&& isdigit(line[2])) {
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/*
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* We have a 3-digit response code.
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*/
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code = (line[0] - '0')*100 + (line[1] - '0')*10 + (line[2] - '0');
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proto_tree_add_uint(cmdresp_tree, hf_smtp_rsp_code, tvb, offset, 3,
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code);
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if (linelen >= 4) {
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proto_tree_add_item(cmdresp_tree, hf_smtp_rsp_parameter, tvb,
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offset + 4, linelen - 4, FALSE);
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}
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}
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/*
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* Step past this line.
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*/
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offset = next_offset;
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/*
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* If it's not a continuation line, quit.
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*/
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if (!is_continuation_line)
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break;
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}
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}
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}
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}
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/* Register all the bits needed by the filtering engine */
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void
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proto_register_smtp(void)
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{
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static hf_register_info hf[] = {
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{ &hf_smtp_req,
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{ "Request", "smtp.req", FT_BOOLEAN, BASE_NONE, NULL, 0x0, "", HFILL }},
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{ &hf_smtp_rsp,
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{ "Response", "smtp.rsp", FT_BOOLEAN, BASE_NONE, NULL, 0x0, "", HFILL }},
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{ &hf_smtp_req_command,
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{ "Command", "smtp.req.command", FT_STRING, BASE_NONE, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_smtp_req_parameter,
|
|
{ "Request parameter", "smtp.req.parameter", FT_STRING, BASE_NONE, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_smtp_rsp_code,
|
|
{ "Response code", "smtp.response.code", FT_UINT32, BASE_DEC, NULL, 0x0,
|
|
"", HFILL }},
|
|
|
|
{ &hf_smtp_rsp_parameter,
|
|
{ "Response parameter", "smtp.rsp.parameter", FT_STRING, BASE_NONE, NULL, 0x0,
|
|
"", HFILL }}
|
|
};
|
|
static gint *ett[] = {
|
|
&ett_smtp,
|
|
&ett_smtp_cmdresp,
|
|
};
|
|
module_t *smtp_module;
|
|
|
|
/* No Configuration options to register? */
|
|
|
|
proto_smtp = proto_register_protocol("Simple Mail Transfer Protocol",
|
|
"SMTP", "smtp");
|
|
|
|
proto_register_field_array(proto_smtp, hf, array_length(hf));
|
|
proto_register_subtree_array(ett, array_length(ett));
|
|
|
|
smtp_module = prefs_register_protocol(proto_smtp, NULL);
|
|
prefs_register_bool_preference(smtp_module, "desegment_lines",
|
|
"Reassemble SMTP command and response lines\nspanning multiple TCP segments",
|
|
"Whether the SMTP dissector should reassemble command and response lines spanning multiple TCP segments."
|
|
" To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
|
|
&smtp_desegment);
|
|
}
|
|
|
|
/* The registration hand-off routine */
|
|
void
|
|
proto_reg_handoff_smtp(void)
|
|
{
|
|
dissector_handle_t smtp_handle;
|
|
|
|
smtp_handle = create_dissector_handle(dissect_smtp, proto_smtp);
|
|
dissector_add("tcp.port", TCP_PORT_SMTP, smtp_handle);
|
|
}
|