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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-ipv4hdr.h"
/* prototypes */
static int DetectIpv4hdrSetup (DetectEngineCtx *, Signature *, const char *);
#ifdef UNITTESTS
void DetectIpv4hdrRegisterTests (void);
#endif
static int g_ipv4hdr_buffer_id = 0;
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Packet *p, const int list_id);
/**
* \brief Registration function for ipv4.hdr: keyword
*/
void DetectIpv4hdrRegister(void)
{
sigmatch_table[DETECT_IPV4HDR].name = "ipv4.hdr";
sigmatch_table[DETECT_IPV4HDR].desc = "sticky buffer to match on the IPV4 header";
sigmatch_table[DETECT_IPV4HDR].url = "/rules/header-keywords.html#ipv4hdr";
sigmatch_table[DETECT_IPV4HDR].Setup = DetectIpv4hdrSetup;
sigmatch_table[DETECT_IPV4HDR].flags |= SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;
#ifdef UNITTESTS
sigmatch_table[DETECT_IPV4HDR].RegisterTests = DetectIpv4hdrRegisterTests;
#endif
g_ipv4hdr_buffer_id = DetectBufferTypeRegister("ipv4.hdr");
BUG_ON(g_ipv4hdr_buffer_id < 0);
DetectBufferTypeSupportsPacket("ipv4.hdr");
DetectPktMpmRegister("ipv4.hdr", 2, PrefilterGenericMpmPktRegister, GetData);
DetectPktInspectEngineRegister("ipv4.hdr", GetData,
DetectEngineInspectPktBufferGeneric);
return;
}
/**
* \brief setup ipv4.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 DetectIpv4hdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
{
s->proto.flags |= DETECT_PROTO_IPV4; // TODO
s->flags |= SIG_FLAG_REQUIRE_PACKET;
if (DetectBufferSetActiveList(de_ctx, s, g_ipv4hdr_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->ip4h == NULL) {
// DETECT_PROTO_IPV4 does not prefilter
return NULL;
}
uint32_t hlen = IPV4_GET_HLEN(p);
if (((uint8_t *)p->ip4h + (ptrdiff_t)hlen) >
((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
{
SCLogDebug("data out of range: %p > %p",
((uint8_t *)p->ip4h + (ptrdiff_t)hlen),
((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
return NULL;
}
const uint32_t data_len = hlen;
const uint8_t *data = (const uint8_t *)p->ip4h;
InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
#ifdef UNITTESTS
#include "tests/detect-ipv4hdr.c"
#endif
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