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130 lines
3.9 KiB
C
130 lines
3.9 KiB
C
/* Copyright (C) 2007-2019 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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* \file
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*
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* \author Victor Julien <victor@inliniac.net>
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*
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*/
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#include "suricata-common.h"
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#include "detect.h"
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#include "detect-parse.h"
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#include "detect-engine.h"
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#include "detect-engine-mpm.h"
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#include "detect-engine-prefilter.h"
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#include "detect-engine-content-inspection.h"
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#include "detect-fast-pattern.h"
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#include "detect-ipv4hdr.h"
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/* prototypes */
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static int DetectIpv4hdrSetup (DetectEngineCtx *, Signature *, const char *);
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#ifdef UNITTESTS
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void DetectIpv4hdrRegisterTests (void);
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#endif
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static int g_ipv4hdr_buffer_id = 0;
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static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
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const DetectEngineTransforms *transforms, Packet *p, const int list_id);
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/**
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* \brief Registration function for ipv4.hdr: keyword
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*/
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void DetectIpv4hdrRegister(void)
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{
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sigmatch_table[DETECT_IPV4HDR].name = "ipv4.hdr";
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sigmatch_table[DETECT_IPV4HDR].desc = "sticky buffer to match on the IPV4 header";
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sigmatch_table[DETECT_IPV4HDR].url = "/rules/header-keywords.html#ipv4hdr";
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sigmatch_table[DETECT_IPV4HDR].Setup = DetectIpv4hdrSetup;
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sigmatch_table[DETECT_IPV4HDR].flags |= SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;
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#ifdef UNITTESTS
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sigmatch_table[DETECT_IPV4HDR].RegisterTests = DetectIpv4hdrRegisterTests;
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#endif
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g_ipv4hdr_buffer_id = DetectBufferTypeRegister("ipv4.hdr");
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BUG_ON(g_ipv4hdr_buffer_id < 0);
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DetectBufferTypeSupportsPacket("ipv4.hdr");
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DetectPktMpmRegister("ipv4.hdr", 2, PrefilterGenericMpmPktRegister, GetData);
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DetectPktInspectEngineRegister("ipv4.hdr", GetData,
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DetectEngineInspectPktBufferGeneric);
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return;
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}
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/**
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* \brief setup ipv4.hdr sticky buffer
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*
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* \param de_ctx pointer to the Detection Engine Context
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* \param s pointer to the Current Signature
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* \param _unused unused
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*
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* \retval 0 on Success
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* \retval -1 on Failure
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*/
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static int DetectIpv4hdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
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{
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s->proto.flags |= DETECT_PROTO_IPV4; // TODO
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s->flags |= SIG_FLAG_REQUIRE_PACKET;
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if (DetectBufferSetActiveList(s, g_ipv4hdr_buffer_id) < 0)
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return -1;
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return 0;
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}
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static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
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const DetectEngineTransforms *transforms, Packet *p, const int list_id)
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{
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SCEnter();
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InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
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if (buffer->inspect == NULL) {
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if (p->ip4h == NULL) {
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// DETECT_PROTO_IPV4 does not prefilter
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return NULL;
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}
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uint32_t hlen = IPV4_GET_HLEN(p);
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if (((uint8_t *)p->ip4h + (ptrdiff_t)hlen) >
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((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
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{
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SCLogDebug("data out of range: %p > %p",
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((uint8_t *)p->ip4h + (ptrdiff_t)hlen),
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((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
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return NULL;
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}
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const uint32_t data_len = hlen;
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const uint8_t *data = (const uint8_t *)p->ip4h;
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InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
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InspectionBufferApplyTransforms(buffer, transforms);
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}
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return buffer;
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}
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#ifdef UNITTESTS
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#include "tests/detect-ipv4hdr.c"
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#endif
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