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113 lines
3.3 KiB
C
113 lines
3.3 KiB
C
/* Copyright (C) 2015-2021 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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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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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \ingroup decode
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*
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* @{
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*/
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/**
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* \file
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*
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* \author XXX Your Name <your@email.com>
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*
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* Decodes XXX describe the protocol
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*/
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#include "suricata-common.h"
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#include "suricata.h"
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#include "decode.h"
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#include "decode-events.h"
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#include "decode-template.h"
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#include "util-validate.h"
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/**
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* \brief Function to decode TEMPLATE packets
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* \param tv thread vars
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* \param dtv decoder thread vars
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* \param p packet
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* \param pkt raw packet data
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* \param len length in bytes of pkt array
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* \retval TM_ECODE_OK or TM_ECODE_FAILED on serious error
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*/
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int DecodeTEMPLATE(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p,
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const uint8_t *pkt, uint32_t len)
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{
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DEBUG_VALIDATE_BUG_ON(pkt == NULL);
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/* TODO add counter for your type of packet to DecodeThreadVars,
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* and register it in DecodeRegisterPerfCounters */
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//StatsIncr(tv, dtv->counter_template);
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/* Validation: make sure that the input data is big enough to hold
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* the header */
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if (len < sizeof(TemplateHdr)) {
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/* in case of errors, we set events. Events are defined in
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* decode-events.h, and are then exposed to the detection
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* engine through detect-engine-events.h */
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//ENGINE_SET_EVENT(p,TEMPLATE_HEADER_TOO_SMALL);
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return TM_ECODE_FAILED;
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}
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/* Each packet keeps a count of decoded layers
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* This function increases it and returns false
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* if we have too many decoded layers, such as
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* ethernet/MPLS/ethernet/MPLS... which may
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* lead to stack overflow by a too deep recursion
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*/
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if (!PacketIncreaseCheckLayers(p)) {
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return TM_ECODE_FAILED;
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}
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/* Now we can access the header */
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const TemplateHdr *hdr = (const TemplateHdr *)pkt;
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/* lets assume we have UDP encapsulated */
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if (hdr->proto == 17) {
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/* we need to pass on the pkt and it's length minus the current
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* header */
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size_t hdr_len = sizeof(TemplateHdr);
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/* in this example it's clear that hdr_len can't be bigger than
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* 'len', but in more complex cases checking that we can't underflow
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* len is very important
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if (hdr_len >= len) {
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ENGINE_SET_EVENT(p,TEMPLATE_MALFORMED_HDRLEN);
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return TM_ECODE_FAILED;
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}
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*/
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if (unlikely(len - hdr_len > USHRT_MAX)) {
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return TM_ECODE_FAILED;
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}
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/* invoke the next decoder on the remainder of the data */
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return DecodeUDP(tv, dtv, p, (uint8_t *)pkt + hdr_len, (uint16_t)(len - hdr_len));
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} else {
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//ENGINE_SET_EVENT(p,TEMPLATE_UNSUPPORTED_PROTOCOL);
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return TM_ECODE_FAILED;
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}
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return TM_ECODE_OK;
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}
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/**
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* @}
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*/
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