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360 lines
12 KiB
C
360 lines
12 KiB
C
/* Copyright (C) 2007-2020 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 Breno Silva <breno.silva@gmail.com>
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* \author Victor Julien <victor@inliniac.net>
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*
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* Implements fragbits keyword
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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 "rust.h"
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#include "detect.h"
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#include "detect-parse.h"
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#include "detect-engine-prefilter.h"
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#include "detect-engine-prefilter-common.h"
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#include "detect-engine-uint.h"
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#include "flow-var.h"
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#include "decode-events.h"
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#include "app-layer.h"
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#include "app-layer-detect-proto.h"
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#include "detect-fragbits.h"
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#include "util-unittest.h"
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#include "util-debug.h"
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#include "pkt-var.h"
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#include "host.h"
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#include "util-profiling.h"
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static int DetectFragBitsMatch (DetectEngineThreadCtx *, Packet *,
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const Signature *, const SigMatchCtx *);
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static int DetectFragBitsSetup (DetectEngineCtx *, Signature *, const char *);
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static void DetectFragBitsFree(DetectEngineCtx *, void *);
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static int PrefilterSetupFragBits(DetectEngineCtx *de_ctx, SigGroupHead *sgh);
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static bool PrefilterFragBitsIsPrefilterable(const Signature *s);
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#ifdef UNITTESTS
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static void FragBitsRegisterTests(void);
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#endif
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/**
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* \brief Registration function for fragbits: keyword
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*/
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void DetectFragBitsRegister (void)
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{
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sigmatch_table[DETECT_FRAGBITS].name = "fragbits";
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sigmatch_table[DETECT_FRAGBITS].desc = "check if the fragmentation and reserved bits are set in the IP header";
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sigmatch_table[DETECT_FRAGBITS].url = "/rules/header-keywords.html#fragbits-ip-fragmentation";
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sigmatch_table[DETECT_FRAGBITS].Match = DetectFragBitsMatch;
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sigmatch_table[DETECT_FRAGBITS].Setup = DetectFragBitsSetup;
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sigmatch_table[DETECT_FRAGBITS].Free = DetectFragBitsFree;
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#ifdef UNITTESTS
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sigmatch_table[DETECT_FRAGBITS].RegisterTests = FragBitsRegisterTests;
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#endif
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sigmatch_table[DETECT_FRAGBITS].SetupPrefilter = PrefilterSetupFragBits;
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sigmatch_table[DETECT_FRAGBITS].SupportsPrefilter = PrefilterFragBitsIsPrefilterable;
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sigmatch_table[DETECT_FRAGBITS].flags = SIGMATCH_INFO_UINT16 | SIGMATCH_INFO_BITFLAGS_UINT;
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}
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/**
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* \internal
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* \brief This function is used to match fragbits on a packet with those passed via fragbits:
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*
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* \param t pointer to thread vars
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* \param det_ctx pointer to the pattern matcher thread
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* \param p pointer to the current packet
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* \param s pointer to the Signature
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* \param m pointer to the sigmatch
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*
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* \retval 0 no match
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* \retval 1 match
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*/
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static int DetectFragBitsMatch (DetectEngineThreadCtx *det_ctx,
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Packet *p, const Signature *s, const SigMatchCtx *ctx)
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{
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DEBUG_VALIDATE_BUG_ON(PKT_IS_PSEUDOPKT(p));
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if (!ctx || !PacketIsIPv4(p))
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return 0;
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const IPV4Hdr *ip4h = PacketGetIPv4(p);
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DetectU16Data *du16 = (DetectU16Data *)ctx;
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return DetectU16Match(IPV4_GET_RAW_IPOFFSET(ip4h), du16);
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}
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/**
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* \internal
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* \brief this function is used to add the parsed fragbits into the current signature
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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 m pointer to the Current SigMatch
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* \param rawstr pointer to the user provided fragbits options
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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 DetectFragBitsSetup (DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
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{
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DetectU16Data *du16 = SCDetectIpv4FragbitsParse(rawstr);
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if (du16 == NULL)
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return -1;
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if (SCSigMatchAppendSMToList(
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de_ctx, s, DETECT_FRAGBITS, (SigMatchCtx *)du16, DETECT_SM_LIST_MATCH) == NULL) {
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goto error;
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}
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s->flags |= SIG_FLAG_REQUIRE_PACKET;
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return 0;
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error:
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if (du16)
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DetectFragBitsFree(NULL, du16);
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return -1;
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}
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/**
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* \internal
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* \brief this function will free memory associated with DetectU16Data
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*
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* \param de pointer to DetectU16Data
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*/
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static void DetectFragBitsFree(DetectEngineCtx *de_ctx, void *de_ptr)
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{
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SCDetectU16Free(de_ptr);
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}
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static void
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PrefilterPacketFragBitsMatch(DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx)
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{
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DEBUG_VALIDATE_BUG_ON(PKT_IS_PSEUDOPKT(p));
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const PrefilterPacketHeaderCtx *ctx = pectx;
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if (!PacketIsIPv4(p))
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return;
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const IPV4Hdr *ip4h = PacketGetIPv4(p);
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DetectU16Data du16;
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du16.mode = ctx->v1.u8[0];
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du16.arg1 = ctx->v1.u16[1];
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du16.arg2 = ctx->v1.u16[2];
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if (DetectU16Match(IPV4_GET_RAW_IPOFFSET(ip4h), &du16)) {
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PrefilterAddSids(&det_ctx->pmq, ctx->sigs_array, ctx->sigs_cnt);
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}
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}
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static int PrefilterSetupFragBits(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
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{
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return PrefilterSetupPacketHeader(de_ctx, sgh, DETECT_FRAGBITS, SIG_MASK_REQUIRE_REAL_PKT,
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PrefilterPacketU16Set, PrefilterPacketU16Compare, PrefilterPacketFragBitsMatch);
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}
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static bool PrefilterFragBitsIsPrefilterable(const Signature *s)
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{
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return PrefilterIsPrefilterableById(s, DETECT_FRAGBITS);
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}
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/*
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* ONLY TESTS BELOW THIS COMMENT
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*/
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#ifdef UNITTESTS
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#include "util-unittest-helper.h"
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#include "packet.h"
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/**
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* \test FragBitsTestParse03 test if DONT FRAG is set. Must return success
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*
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* \retval 1 on success
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* \retval 0 on failure
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*/
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static int FragBitsTestParse03 (void)
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{
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uint8_t raw_eth[] = {
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0x00 ,0x40 ,0x33 ,0xd9 ,0x7c ,0xfd ,0x00 ,0x00,
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0x39 ,0xcf ,0xd9 ,0xcd ,0x08 ,0x00 ,0x45 ,0x00,
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0x01 ,0x13 ,0x9c ,0x5d ,0x40 ,0x00 ,0xf6 ,0x11,
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0x44 ,0xca ,0x97 ,0xa4 ,0x01 ,0x08 ,0x0a ,0x00,
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0x00 ,0x06 ,0x00 ,0x35 ,0x04 ,0x0b ,0x00 ,0xff,
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0x3c ,0x87 ,0x7d ,0x9e ,0x85 ,0x80 ,0x00 ,0x01,
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0x00 ,0x01 ,0x00 ,0x05 ,0x00 ,0x05 ,0x06 ,0x70,
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0x69 ,0x63 ,0x61 ,0x72 ,0x64 ,0x07 ,0x75 ,0x74,
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0x68 ,0x73 ,0x63 ,0x73 ,0x61 ,0x03 ,0x65 ,0x64,
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0x75 ,0x00 ,0x00 ,0x01 ,0x00 ,0x01 ,0xc0 ,0x0c,
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0x00 ,0x01 ,0x00 ,0x01 ,0x00 ,0x00 ,0x0e ,0x10,
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0x00 ,0x04 ,0x81 ,0x6f ,0x1e ,0x1b ,0x07 ,0x75,
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0x74 ,0x68 ,0x73 ,0x63 ,0x73 ,0x61 ,0x03 ,0x65,
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0x64 ,0x75 ,0x00 ,0x00 ,0x02 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x09 ,0x06 ,0x6b ,0x65,
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0x6e ,0x6f ,0x62 ,0x69 ,0xc0 ,0x34 ,0xc0 ,0x34,
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0x00 ,0x02 ,0x00 ,0x01 ,0x00 ,0x00 ,0x0e ,0x10,
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0x00 ,0x07 ,0x04 ,0x6a ,0x69 ,0x6e ,0x6e ,0xc0,
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0x34 ,0xc0 ,0x34 ,0x00 ,0x02 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x0c ,0x04 ,0x64 ,0x6e,
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0x73 ,0x31 ,0x04 ,0x6e ,0x6a ,0x69 ,0x74 ,0xc0,
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0x3c ,0xc0 ,0x34 ,0x00 ,0x02 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x08 ,0x05 ,0x65 ,0x6c,
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0x7a ,0x69 ,0x70 ,0xc0 ,0x34 ,0xc0 ,0x34 ,0x00,
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0x02 ,0x00 ,0x01 ,0x00 ,0x00 ,0x0e ,0x10 ,0x00,
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0x08 ,0x05 ,0x61 ,0x72 ,0x77 ,0x65 ,0x6e ,0xc0,
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0x34 ,0xc0 ,0x4b ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x1a,
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0x06 ,0xc0 ,0x60 ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x1a,
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0x07 ,0xc0 ,0x73 ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x01 ,0x03 ,0x82 ,0x00 ,0x04 ,0x80 ,0xeb ,0xfb,
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0x0a ,0xc0 ,0x8b ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x01,
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0x0b ,0xc0 ,0x9f ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x0b,
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0x51};
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Packet *p = PacketGetFromAlloc();
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FAIL_IF(unlikely(p == NULL));
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&tv, 0, sizeof(ThreadVars));
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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dtv.app_tctx = AppLayerGetCtxThread();
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FlowInitConfig(FLOW_QUIET);
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DecodeEthernet(&tv, &dtv, p, raw_eth, sizeof(raw_eth));
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DetectU16Data *de = SCDetectIpv4FragbitsParse("D");
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FAIL_IF(de == NULL);
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FAIL_IF(de->arg1 != 0x4000);
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FAIL_IF(de->mode != DetectUintModeEqual);
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SigMatch *sm = SigMatchAlloc();
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FAIL_IF(sm == NULL);
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sm->type = DETECT_FRAGBITS;
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sm->ctx = (SigMatchCtx *)de;
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int ret = DetectFragBitsMatch(NULL, p, NULL, sm->ctx);
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FAIL_IF(ret == 0);
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DetectFragBitsFree(NULL, de);
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SCFree(sm);
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PacketFree(p);
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AppLayerDestroyCtxThread(dtv.app_tctx);
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FlowShutdown();
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PASS;
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}
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/**
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* \test FragBitsTestParse04 test if DONT FRAG is not set. Must fails.
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*
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* \retval 1 on success
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* \retval 0 on failure
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*/
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static int FragBitsTestParse04 (void)
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{
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uint8_t raw_eth[] = {
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0x00 ,0x40 ,0x33 ,0xd9 ,0x7c ,0xfd ,0x00 ,0x00,
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0x39 ,0xcf ,0xd9 ,0xcd ,0x08 ,0x00 ,0x45 ,0x00,
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0x01 ,0x13 ,0x9c ,0x5d ,0x40 ,0x00 ,0xf6 ,0x11,
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0x44 ,0xca ,0x97 ,0xa4 ,0x01 ,0x08 ,0x0a ,0x00,
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0x00 ,0x06 ,0x00 ,0x35 ,0x04 ,0x0b ,0x00 ,0xff,
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0x3c ,0x87 ,0x7d ,0x9e ,0x85 ,0x80 ,0x00 ,0x01,
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0x00 ,0x01 ,0x00 ,0x05 ,0x00 ,0x05 ,0x06 ,0x70,
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0x69 ,0x63 ,0x61 ,0x72 ,0x64 ,0x07 ,0x75 ,0x74,
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0x68 ,0x73 ,0x63 ,0x73 ,0x61 ,0x03 ,0x65 ,0x64,
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0x75 ,0x00 ,0x00 ,0x01 ,0x00 ,0x01 ,0xc0 ,0x0c,
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0x00 ,0x01 ,0x00 ,0x01 ,0x00 ,0x00 ,0x0e ,0x10,
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0x00 ,0x04 ,0x81 ,0x6f ,0x1e ,0x1b ,0x07 ,0x75,
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0x74 ,0x68 ,0x73 ,0x63 ,0x73 ,0x61 ,0x03 ,0x65,
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0x64 ,0x75 ,0x00 ,0x00 ,0x02 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x09 ,0x06 ,0x6b ,0x65,
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0x6e ,0x6f ,0x62 ,0x69 ,0xc0 ,0x34 ,0xc0 ,0x34,
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0x00 ,0x02 ,0x00 ,0x01 ,0x00 ,0x00 ,0x0e ,0x10,
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0x00 ,0x07 ,0x04 ,0x6a ,0x69 ,0x6e ,0x6e ,0xc0,
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0x34 ,0xc0 ,0x34 ,0x00 ,0x02 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x0c ,0x04 ,0x64 ,0x6e,
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0x73 ,0x31 ,0x04 ,0x6e ,0x6a ,0x69 ,0x74 ,0xc0,
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0x3c ,0xc0 ,0x34 ,0x00 ,0x02 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x08 ,0x05 ,0x65 ,0x6c,
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0x7a ,0x69 ,0x70 ,0xc0 ,0x34 ,0xc0 ,0x34 ,0x00,
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0x02 ,0x00 ,0x01 ,0x00 ,0x00 ,0x0e ,0x10 ,0x00,
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0x08 ,0x05 ,0x61 ,0x72 ,0x77 ,0x65 ,0x6e ,0xc0,
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0x34 ,0xc0 ,0x4b ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x1a,
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0x06 ,0xc0 ,0x60 ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x1a,
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0x07 ,0xc0 ,0x73 ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x01 ,0x03 ,0x82 ,0x00 ,0x04 ,0x80 ,0xeb ,0xfb,
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0x0a ,0xc0 ,0x8b ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x01,
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0x0b ,0xc0 ,0x9f ,0x00 ,0x01 ,0x00 ,0x01 ,0x00,
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0x00 ,0x0e ,0x10 ,0x00 ,0x04 ,0x81 ,0x6f ,0x0b,
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0x51};
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Packet *p = PacketGetFromAlloc();
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FAIL_IF(unlikely(p == NULL));
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&tv, 0, sizeof(ThreadVars));
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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dtv.app_tctx = AppLayerGetCtxThread();
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FlowInitConfig(FLOW_QUIET);
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DecodeEthernet(&tv, &dtv, p, raw_eth, sizeof(raw_eth));
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DetectU16Data *de = SCDetectIpv4FragbitsParse("!D");
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FAIL_IF(de == NULL);
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FAIL_IF(de->arg1 != 0x4000);
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FAIL_IF(de->arg2 != 0x4000);
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FAIL_IF(de->mode != DetectUintModeNegBitmask);
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SigMatch *sm = SigMatchAlloc();
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FAIL_IF(sm == NULL);
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sm->type = DETECT_FRAGBITS;
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sm->ctx = (SigMatchCtx *)de;
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int ret = DetectFragBitsMatch(NULL, p, NULL, sm->ctx);
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FAIL_IF(ret);
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DetectFragBitsFree(NULL, de);
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SCFree(sm);
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PacketFree(p);
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AppLayerDestroyCtxThread(dtv.app_tctx);
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FlowShutdown();
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PASS;
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}
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/**
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* \brief this function registers unit tests for FragBits
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*/
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static void FragBitsRegisterTests(void)
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{
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UtRegisterTest("FragBitsTestParse03", FragBitsTestParse03);
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UtRegisterTest("FragBitsTestParse04", FragBitsTestParse04);
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}
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#endif /* UNITTESTS */
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