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/* Copyright (C) 2007-2010 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 Brian Rectanus <brectanu@gmail.com>
*
* Implements the seq keyword.
*/
#include "suricata-common.h"
#include "debug.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-seq.h"
#include "util-byte.h"
#include "util-unittest.h"
#include "util-unittest-helper.h"
#include "util-debug.h"
static int DetectSeqSetup(DetectEngineCtx *, Signature *, char *);
static int DetectSeqMatch(ThreadVars *, DetectEngineThreadCtx *,
Packet *, Signature *, const SigMatchCtx *);
static void DetectSeqRegisterTests(void);
static void DetectSeqFree(void *);
void DetectSeqRegister(void)
{
sigmatch_table[DETECT_SEQ].name = "seq";
sigmatch_table[DETECT_SEQ].desc = "check for a specific TCP sequence number";
sigmatch_table[DETECT_SEQ].url = "https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Header_keywords#seq";
sigmatch_table[DETECT_SEQ].Match = DetectSeqMatch;
sigmatch_table[DETECT_SEQ].Setup = DetectSeqSetup;
sigmatch_table[DETECT_SEQ].Free = DetectSeqFree;
sigmatch_table[DETECT_SEQ].RegisterTests = DetectSeqRegisterTests;
}
/**
* \internal
* \brief This function is used to match packets with a given Seq number
*
* \param t pointer to thread vars
* \param det_ctx pointer to the pattern matcher thread
* \param p pointer to the current packet
* \param m pointer to the sigmatch that we will cast into DetectSeqData
*
* \retval 0 no match
* \retval 1 match
*/
static int DetectSeqMatch(ThreadVars *t, DetectEngineThreadCtx *det_ctx,
Packet *p, Signature *s, const SigMatchCtx *ctx)
{
const DetectSeqData *data = (const DetectSeqData *)ctx;
/* This is only needed on TCP packets */
if (!(PKT_IS_TCP(p)) || PKT_IS_PSEUDOPKT(p)) {
return 0;
}
return (data->seq == TCP_GET_SEQ(p)) ? 1 : 0;
}
/**
* \internal
* \brief this function is used to add the seq option into the signature
*
* \param de_ctx pointer to the Detection Engine Context
* \param s pointer to the Current Signature
* \param optstr pointer to the user provided options
*
* \retval 0 on Success
* \retval -1 on Failure
*/
static int DetectSeqSetup (DetectEngineCtx *de_ctx, Signature *s, char *optstr)
{
DetectSeqData *data = NULL;
SigMatch *sm = NULL;
data = SCMalloc(sizeof(DetectSeqData));
if (unlikely(data == NULL))
goto error;
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_SEQ;
if (-1 == ByteExtractStringUint32(&data->seq, 10, 0, optstr)) {
goto error;
}
sm->ctx = (SigMatchCtx*)data;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
s->flags |= SIG_FLAG_REQUIRE_PACKET;
return 0;
error:
if (data)
SCFree(data);
if (sm)
SigMatchFree(sm);
return -1;
}
/**
* \internal
* \brief this function will free memory associated with seq option
*
* \param data pointer to seq configuration data
*/
static void DetectSeqFree(void *ptr)
{
DetectSeqData *data = (DetectSeqData *)ptr;
SCFree(data);
}
#ifdef UNITTESTS
/**
* \test DetectSeqSigTest01 tests parses
*/
static int DetectSeqSigTest01(void)
{
int result = 0;
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL)
goto end;
/* These three are crammed in here as there is no Parse */
if (SigInit(de_ctx,
"alert tcp any any -> any any "
"(msg:\"Testing seq\";seq:foo;sid:1;)") != NULL)
{
printf("invalid seq accepted: ");
goto cleanup;
}
if (SigInit(de_ctx,
"alert tcp any any -> any any "
"(msg:\"Testing seq\";seq:9999999999;sid:1;)") != NULL)
{
printf("overflowing seq accepted: ");
goto cleanup;
}
if (SigInit(de_ctx,
"alert tcp any any -> any any "
"(msg:\"Testing seq\";seq:-100;sid:1;)") != NULL)
{
printf("negative seq accepted: ");
goto cleanup;
}
result = 1;
cleanup:
if (de_ctx) {
SigGroupCleanup(de_ctx);
SigCleanSignatures(de_ctx);
DetectEngineCtxFree(de_ctx);
}
end:
return result;
}
/**
* \test DetectSeqSigTest02 tests seq keyword
*/
static int DetectSeqSigTest02(void)
{
int result = 0;
uint8_t *buf = (uint8_t *)"Hi all!";
uint16_t buflen = strlen((char *)buf);
Packet *p[3];
p[0] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
p[1] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
p[2] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_ICMP);
if (p[0] == NULL || p[1] == NULL ||p[2] == NULL)
goto end;
/* TCP w/seq=42 */
p[0]->tcph->th_seq = htonl(42);
/* TCP w/seq=100 */
p[1]->tcph->th_seq = htonl(100);
char *sigs[2];
sigs[0]= "alert tcp any any -> any any (msg:\"Testing seq\"; seq:41; sid:1;)";
sigs[1]= "alert tcp any any -> any any (msg:\"Testing seq\"; seq:42; sid:2;)";
uint32_t sid[2] = {1, 2};
uint32_t results[3][2] = {
/* packet 0 match sid 1 but should not match sid 2 */
{0, 1},
/* packet 1 should not match */
{0, 0},
/* packet 2 should not match */
{0, 0} };
result = UTHGenericTest(p, 3, sigs, sid, (uint32_t *) results, 2);
UTHFreePackets(p, 3);
end:
return result;
}
#endif /* UNITTESTS */
/**
* \internal
* \brief This function registers unit tests for DetectSeq
*/
static void DetectSeqRegisterTests(void)
{
#ifdef UNITTESTS
UtRegisterTest("DetectSeqSigTest01", DetectSeqSigTest01, 1);
UtRegisterTest("DetectSeqSigTest02", DetectSeqSigTest02, 1);
#endif /* UNITTESTS */
}
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