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/* Copyright (C) 2007-2019 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
*
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-content-inspection.h"
#include "detect-fast-pattern.h"
#include "detect-udphdr.h"
/* prototypes */
static int DetectUdphdrSetup (DetectEngineCtx *, Signature *, const char *);
#ifdef UNITTESTS
void DetectUdphdrRegisterTests (void);
#endif
static int g_udphdr_buffer_id = 0;
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Packet *p, const int list_id);
/**
* \brief Registration function for udp.hdr: keyword
*/
void DetectUdphdrRegister(void)
{
sigmatch_table[DETECT_UDPHDR].name = "udp.hdr";
sigmatch_table[DETECT_UDPHDR].desc = "sticky buffer to match on the UDP header";
sigmatch_table[DETECT_UDPHDR].url = "/rules/header-keywords.html#udphdr";
sigmatch_table[DETECT_UDPHDR].Setup = DetectUdphdrSetup;
sigmatch_table[DETECT_UDPHDR].flags |= SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;
#ifdef UNITTESTS
sigmatch_table[DETECT_UDPHDR].RegisterTests = DetectUdphdrRegisterTests;
#endif
g_udphdr_buffer_id = DetectBufferTypeRegister("udp.hdr");
BUG_ON(g_udphdr_buffer_id < 0);
DetectBufferTypeSupportsPacket("udp.hdr");
DetectPktMpmRegister("udp.hdr", 2, PrefilterGenericMpmPktRegister, GetData);
DetectPktInspectEngineRegister("udp.hdr", GetData,
DetectEngineInspectPktBufferGeneric);
return;
}
/**
* \brief set up the udp.hdr sticky buffer
*
* \param de_ctx pointer to the Detection Engine Context
* \param s pointer to the Current Signature
* \param _unused unused
*
* \retval 0 on Success
* \retval -1 on Failure
*/
static int DetectUdphdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
{
if (!(DetectProtoContainsProto(&s->proto, IPPROTO_UDP)))
return -1;
s->flags |= SIG_FLAG_REQUIRE_PACKET;
if (DetectBufferSetActiveList(de_ctx, s, g_udphdr_buffer_id) < 0)
return -1;
return 0;
}
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Packet *p, const int list_id)
{
SCEnter();
InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
if (buffer->inspect == NULL) {
if (p->udph == NULL) {
return NULL;
}
if (((uint8_t *)p->udph + (ptrdiff_t)UDP_HEADER_LEN) >
((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
{
SCLogDebug("data out of range: %p > %p",
((uint8_t *)p->udph + (ptrdiff_t)UDP_HEADER_LEN),
((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
return NULL;
}
const uint32_t data_len = UDP_HEADER_LEN;
const uint8_t *data = (const uint8_t *)p->udph;
InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
#ifdef UNITTESTS
#include "tests/detect-udphdr.c"
#endif
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